INTL SPACE STATION LENTICULAR 3D PUZZLE 50pc 9" NASA space satellite JAXA moon

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Seller: sidewaysstairsco ✉️ (1,180) 100%, Location: Santa Ana, California, US, Ships to: US & many other countries, Item: 204318493016 INTL SPACE STATION LENTICULAR 3D PUZZLE 50pc 9" NASA space satellite JAXA moon. Check out our other new and used items>>>>>HERE! (click me) FOR SALE: An awesome, NASA/space-themed lenticular 3D jigsaw puzzle 2020 DISCOVERY "SATELLITE IN SPACE" PUZZLE BY PRIME 3D (9" X 6") DETAILS: It's the Intl. Space Station in puzzle form! The Discovery "Satellite in Space" 50-piece lenticular jigsaw puzzle features a graphic that utilizes an official orbital photograph of the collaborative International Space Station. Discovery took some artistic liberty by adding more more mesmerizing color and shape to the background. And what makes the puzzle image even more awesome is that Prime 3D Global utilized their high-quality lenticular printing technology to make it "3D" art. The International Space Station is the largest low-earth-orbiting modular space station and involves five space agencies from the globe: the United States' NASA, Russia's Roscosmos, Japan's JAXA, Europe's ESA, and Canada's CSA. Today the I.S.S. has remained in Earth's orbit for nearly 25 years (November 20, 1998), is still operational, and still provides space agencies with assistance and data, though recently a de-orbiting plan was agreed on for January 2031. Prime 3D Global also printed the beautiful graphic on a separate lenticular card and attached it to the front of the box to showcase the puzzle's main feature. This small "3D" art jigsaw puzzle would look great framed! Hang on a deserving wall or display on a shelf or mantel. Perfect for a space-themed bar or man cave. A must have for the lenticular art and space fanatic especially those who collect all things NASA! Brand: Discovery Title: "Satellite in Space" Year: 2020 Piece Count: 50 Completed Size: 9 x 6 in. (22.9 x 15.2 cm) Manufacturer: Prime 3D Global Country: China CONDITION: New in box. Box may have shelf wear. Please see photos. To ensure safe delivery all items are carefully packaged before shipping out. THANK YOU FOR LOOKING. QUESTIONS? JUST ASK. *ALL PHOTOS AND TEXT ARE INTELLECTUAL PROPERTY OF SIDEWAYS STAIRS CO. ALL RIGHTS RESERVED.* "The International Space Station programme is tied together by a complex set of legal, political and financial agreements between the fifteen nations involved in the project, governing ownership of the various components, rights to crewing and utilisation, and responsibilities for crew rotation and resupply of the International Space Station. It was conceived in September 1993 by the United States and Russia after 1980s plans for separate American (Freedom) and Soviet (Mir-2) space stations failed due to budgetary reasons.[2] These agreements tie together the five space agencies and their respective International Space Station programmes and govern how they interact with each other on a daily basis to maintain station operations, from traffic control of spacecraft to and from the station, to utilisation of space and crew time. In March 2010, the International Space Station Program Managers from each of the five partner agencies were presented with Aviation Week's Laureate Award in the Space category,[3] and the ISS programme was awarded the 2009 Collier Trophy. History and conception In the early 1980s, NASA planned to launch a modular space station called Freedom as a counterpart to the Soviet Salyut and Mir space stations. In 1984 the ESA was invited to participate in Space Station Freedom, and the ESA approved the Columbus laboratory by 1987.[4] The Japanese Experiment Module (JEM), or Kibō, was announced in 1985, as part of the Freedom space station in response to a NASA request in 1982. In early 1985, science ministers from the European Space Agency (ESA) countries approved the Columbus programme, the most ambitious effort in space undertaken by that organisation at the time. The plan spearheaded by Germany and Italy included a module which would be attached to Freedom, and with the capability to evolve into a full-fledged European orbital outpost before the end of the century. The space station was also going to tie the emerging European and Japanese national space programmes closer to the US-led project, thereby preventing those nations from becoming major, independent competitors too.[5] In September 1993, American Vice-President Al Gore and Russian Prime Minister Viktor Chernomyrdin announced plans for a new space station, which eventually became the International Space Station.[6] They also agreed, in preparation for this new project, that the United States would be involved in the Mir programme, including American Shuttles docking, in the Shuttle–Mir programme.[7] On 12 April 2021, at a meeting with Russian President Vladimir Putin, then-Deputy Prime Minister Yury Borisov announced he had decided that Russia might withdraw from the ISS programme in 2025.[8][9] According to Russian authorities, the timeframe of the station's operations has expired and its condition leaves much to be desired.[8] On 26 July 2022, Borisov, who had become head of Roscosmos, submitted to Putin his plans for withdrawal from the programme after 2024.[10] However, Robyn Gatens, the NASA official in charge of space station operations, responded that NASA had not received any formal notices from Roscosmos concerning withdrawal plans.[11] On 21 September 2022, Borisov stated that Russia was "highly likely" to continue to participate in the ISS programme until 2028.[12] 1998 agreement A commemorative plaque honouring Space Station Intergovernmental Agreement signed on January 29, 1998 The legal structure that regulates the station is multi-layered. The primary layer establishing obligations and rights between the ISS partners is the Space Station Intergovernmental Agreement (IGA), an international treaty signed on January 28, 1998 by fifteen governments involved in the space station project. The ISS consists of Canada, Japan, the Russian Federation, the United States, and eleven Member States of the European Space Agency (Belgium, Denmark, France, Germany, Italy, The Netherlands, Norway, Spain, Sweden, Switzerland and the United Kingdom).[13] Article 1 outlines its purpose:     This Agreement is a long term international co-operative framework on the basis of genuine partnership, for the detailed design, development, operation, and utilization of a permanently inhabited civil Space Station for peaceful purposes, in accordance with international law.[14] The IGA sets the stage for a second layer of agreements between the partners referred to as 'Memoranda of Understanding' (MOUs), of which four exist between NASA and each of the four other partners. There are no MOUs between ESA, Roskosmos, CSA and JAXA because NASA is the designated manager of the ISS. The MOUs are used to describe the roles and responsibilities of the partners in more detail. A third layer consists of bartered contractual agreements or the trading of the partners' rights and duties, including the 2005 commercial framework agreement between NASA and Roscosmos that sets forth the terms and conditions under which NASA purchases seats on Soyuz crew transporters and cargo capacity on uncrewed Progress transporters. A fourth legal layer of agreements implements and supplements the four MOUs further. Notably among them is the ISS code of conduct made in 2000, setting out criminal jurisdiction, anti-harassment and certain other behavior rules for ISS crewmembers.[15] Programme operations Expeditions This section is an excerpt from International Space Station § Expeditions.[edit] Zarya and Unity were entered for the first time on 10 December 1998. Soyuz TM-31 being prepared to bring the first resident crew to the station in October 2000 Each permanent crew is given an expedition number. Expeditions run up to six months, from launch until undocking, an 'increment' covers the same time period, but includes cargo spacecraft and all activities. Expeditions 1 to 6 consisted of three-person crews. Expeditions 7 to 12 were reduced to the safe minimum of two following the destruction of the NASA Shuttle Columbia. From Expedition 13 the crew gradually increased to six around 2010.[16][17] With the arrival of crew on US commercial vehicles beginning in 2020,[18] NASA has indicated that expedition size may be increased to seven crew members, the number ISS was originally designed for.[19][20] Private flights This section is an excerpt from International Space Station § Private flights.[edit] Travellers who pay for their own passage into space are termed spaceflight participants by Roscosmos and NASA, and are sometimes referred to as "space tourists", a term they generally dislike.[a] As of 2021, seven space tourists have visited the ISS; all seven were transported to the ISS on Russian Soyuz spacecraft. When professional crews change over in numbers not divisible by the three seats in a Soyuz, and a short-stay crewmember is not sent, the spare seat is sold by MirCorp through Space Adventures. Space tourism was halted in 2011 when the Space Shuttle was retired and the station's crew size was reduced to six, as the partners relied on Russian transport seats for access to the station. Soyuz flight schedules increased after 2013, allowing five Soyuz flights (15 seats) with only two expeditions (12 seats) required.[28] The remaining seats were to be sold for around US$40 million to members of the public who could pass a medical exam. ESA and NASA criticised private spaceflight at the beginning of the ISS, and NASA initially resisted training Dennis Tito, the first person to pay for his own passage to the ISS.[b] Anousheh Ansari became the first self-funded woman to fly to the ISS as well as the first Iranian in space. Officials reported that her education and experience made her much more than a tourist, and her performance in training had been "excellent."[29] She did Russian and European studies involving medicine and microbiology during her 10-day stay. The 2009 documentary Space Tourists follows her journey to the station, where she fulfilled "an age-old dream of man: to leave our planet as a 'normal person' and travel into outer space."[30] In 2008, spaceflight participant Richard Garriott placed a geocache aboard the ISS during his flight.[31] This is currently the only non-terrestrial geocache in existence.[32] At the same time, the Immortality Drive, an electronic record of eight digitised human DNA sequences, was placed aboard the ISS.[33] Fleet operations This section is an excerpt from International Space Station § Fleet operations.[edit] Dragon and Cygnus cargo vessels were docked at the ISS together for the first time in April 2016. Japan's Kounotori 4 berthing Commercial Crew Program vehicles Starliner and Dragon A wide variety of crewed and uncrewed spacecraft have supported the station's activities. Flights to the ISS include 37 Space Shuttle missions, 83 Progress resupply spacecraft (including the modified M-MIM2, M-SO1 and M-UM module transports), 63 crewed Soyuz spacecraft, 5 European ATVs, 9 Japanese HTVs, 1 Boeing Starliner, 30 SpaceX Dragon ( both crewed and uncrewed) and 18 Cygnus missions.[34] There are currently twelve available docking ports for visiting spacecraft:[35]     Harmony forward (with IDA 2)     Harmony zenith (with IDA 3)     Harmony nadir     Unity nadir     Prichal nadir     Prichal aft     Prichal forward     Prichal starboard     Prichal port     Nauka forward[36]     Poisk zenith     Rassvet nadir     Zvezda aft Crewed This section is an excerpt from List of human spaceflights to the International Space Station.[edit] As of 29 March 2023, 266 people from 20 countries had visited the space station, many of them multiple times. The United States sent 162 people, Russia sent 57, 11 were Japanese, nine were Canadian, five were Italian, four were French, four were German, and there were one each from Belgium, two from the United Arab Emirates, one from Brazil, Denmark, Great Britain, Kazakhstan, Malaysia, the Netherlands, South Africa, South Korea, Spain, Sweden and Israel.[37] As of March 2023, the United Arab Emirates has sent its second astronaut. Uncrewed This paragraph is an excerpt from Uncrewed spaceflights to the International Space Station.[edit] Uncrewed spaceflights to the International Space Station (ISS) are made primarily to deliver cargo, however several Russian modules have also docked to the outpost following uncrewed launches. Resupply missions typically use the Russian Progress spacecraft, European Automated Transfer Vehicles, Japanese Kounotori vehicles, and the American Dragon and Cygnus spacecraft. The primary docking system for Progress spacecraft is the automated Kurs system, with the manual TORU system as a backup. ATVs also use Kurs, however they are not equipped with TORU. The other spacecraft — the Japanese HTV, the SpaceX Dragon (under CRS phase 1) and the Northrop Grumman[38] Cygnus — rendezvous with the station before being grappled using Canadarm2 and berthed at the nadir port of the Harmony or Unity module for one to two months. Progress, Cygnus and ATV can remain docked for up to six months.[39][40] Under CRS phase 2, Cargo Dragon docks autonomously at IDA-2 or 3 as the case may be. As of December 2022, Progress spacecraft have flown most of the uncrewed missions to the ISS. To avoid confusion, this list includes Soyuz MS-23, which was launched uncrewed and will land crewed, but does not include Soyuz MS-22, which was launched crewed and landed uncrewed, which is listed at List of human spaceflights to the International Space Station. Repairs This section is an excerpt from Maintenance of the International Space Station.[edit] Astronaut Scott Parazynski of STS-120 conducted a 7-hour, 19-minute spacewalk to repair (essentially sew) a damaged solar panel which helps supply power to the International Space Station. NASA considered the spacewalk dangerous with potential risk of electrical shock. Since construction started, the International Space Station programme has had to deal with several maintenance issues, unexpected problems and failures. These incidents have affected the assembly timeline, led to periods of reduced capabilities of the station and in some cases could have forced the crew to abandon the space station for safety reasons, had these problems not been resolved. Mission control centres The components of the ISS are operated and monitored by their respective space agencies at mission control centres across the globe, including:     Roscosmos' RKA Mission Control Center at Korolyov, Russia — manages the maintaining of the station, controls launches of the crewed missions, guides launches from Baikonur Cosmodrome     ESA's ATV Control Centre, at the Toulouse Space Centre (CST) in Toulouse, France – controlled flights of the uncrewed European Automated Transfer Vehicle[41]     JAXA's JEM Control Center and HTV Control Center at Tsukuba Space Center (TKSC) in Ibaraki, Japan – responsible for operating the Kibō complex and all flights of the White Stork HTV Cargo spacecraft, respectively[41]     NASA's Christopher C. Kraft Jr. Mission Control Center at Lyndon B. Johnson Space Center in Houston, Texas – serves as the primary control facility for the United States segment of the ISS[41]     NASA's Payload Operations and Integration Center at Marshall Space Flight Center in Huntsville, Alabama – coordinates payload operations in the USOS[41]     ESA's Columbus Control Center at the German Aerospace Center in Oberpfaffenhofen, Germany – manages the European Columbus research laboratory[41]     CSA's MSS Control at Saint-Hubert, Quebec, Canada – controls and monitors the Mobile Servicing System[41] A world map highlighting the locations of space centres. See adjacent text for details. Space centres involved with the ISS programme Politics This section is an excerpt from Politics of the International Space Station.[edit]    This article needs to be updated. Please help update this article to reflect recent events or newly available information. (July 2022) A world map highlighting Belgium, Denmark, France, Germany, Italy, Netherlands, Norway, Spain, Sweden and Switzerland in red and Brazil in pink. See adjacent text for details.   Primary contributing nations   Formerly contracted nations Politics of the International Space Station have been affected by superpower rivalries, international treaties and funding arrangements. The Cold War was an early factor, overtaken in recent years by the United States' distrust of China. The station has an international crew, with the use of their time, and that of equipment on the station, being governed by treaties between participant nations. Usage of crew and hardware This section is an excerpt from Politics of the International Space Station § Usage of crew and hardware.[edit] Four pie charts indicating how each part of the American segment of the ISS is allocated. See adjacent text for details. Allocation of US Orbital Segment hardware usage between nations. There is no fixed percentage of ownership for the whole space station. Rather, Article 5 of the IGA sets forth that each partner shall retain jurisdiction and control over the elements it registers and over personnel in or on the Space Station who are its nationals.[42] Therefore, for each ISS module only one partner retains sole ownership. Still, the agreements to use the space station facilities are more complex. The station is composed of two sides: the Russian Orbital Segment (ROS) and U.S. Orbital Segment (USOS).[43]     Russian Orbital Segment (mostly Russian ownership, except the Zarya module)         Zarya: first component of the Space Station, storage, USSR/Russia-built, U.S.-funded (hence U.S.-owned)         Zvezda: the functional centre of the Russian portion, living quarters, Russia-owned         Pirs: airlock, docking, Russia-owned (Decommissioned)         Poisk: redundancy for Pirs, Russia-owned         Rassvet: storage, docking, Russia-owned         Nauka: Russian multipurpose laboratory module     U.S. Orbital Segment (mixed U.S. and international ownership)         Columbus laboratory: 51% for ESA, 46.7% for NASA and 2.3% for CSA.[44]         Kibō laboratory: Japanese module, 51% for JAXA, 46.7% for NASA and 2.3% for CSA.[45]         Destiny laboratory: 97.7% for NASA and 2.3% for CSA.[46]         Crew time, electrical power and rights to purchase supporting services (such as data upload & download and communications) are divided 76.6% for NASA, 12.8% for JAXA, 8.3% for ESA, and 2.3% for CSA.[44][45][46] Future of the ISS The heads of the ISS agencies from Canada, Europe, Japan, Russia and the United States meet in Tokyo to review ISS cooperation. Former NASA Administrator Michael D. Griffin says the International Space Station has a role to play as NASA moves forward with a new focus for the crewed space programme, which is to go out beyond Earth orbit for purposes of human exploration and scientific discovery. "The International Space Station is now a stepping stone on the way, rather than being the end of the line," Griffin said.[47] Griffin has said that station crews will not only continue to learn how to live and work in space, but also will learn how to build hardware that can survive and function for the years required to make the round-trip voyage from Earth to Mars.[47] Despite this view, however, in an internal e-mail leaked to the press on August 18, 2008 from Griffin to NASA managers,[48][49][50] Griffin apparently communicated his belief that the current US administration had made no viable plan for US crews to participate in the ISS beyond 2011, and that the Office of Management and Budget (OMB) and Office of Science and Technology Policy (OSTP) were actually seeking its demise.[49] The e-mail appeared to suggest that Griffin believed the only reasonable solution was to extend the operation of the Space Shuttle beyond 2010, but noted that Executive Policy (i.e. the White House) was firm that there would be no extension of the Space Shuttle retirement date, and thus no US capability to launch crews into orbit until the Orion spacecraft would become operational in 2020 as part of the Constellation programme. He did not see purchase of Russian launches for NASA crews as politically viable following the 2008 South Ossetia war, and hoped the incoming Barack Obama administration would resolve the issue in 2009 by extending Space Shuttle operations beyond 2010. A solicitation issued by NASA JSC indicates NASA's intent to purchase from Roscosmos "a minimum of 3 Soyuz seats up to a maximum of 24 seats beginning in the Spring of 2012" to provide ISS crew transportation.[51][52] On September 7, 2008, NASA released a statement regarding the leaked email, in which Griffin said:     The leaked internal email fails to provide the contextual framework for my remarks, and my support for the administration's policies. Administration policy is to retire the shuttle in 2010 and purchase crew transport from Russia until Ares and Orion are available. The administration continues to support our request for an INKSNA exemption. Administration policy continues to be that we will take no action to preclude continued operation of the International Space Station past 2016. I strongly support these administration policies, as do OSTP and OMB.     — Michael D. Griffin[53] On October 15, 2008, President Bush signed the NASA Authorization Act of 2008, giving NASA funding for one additional mission to "deliver science experiments to the station".[54][55][56][57] The Act allows for an additional Space Shuttle flight, STS-134, to the ISS to install the Alpha Magnetic Spectrometer, which was previously cancelled.[58] President of the United States Barack Obama has supported the continued operation of the station, and supported the NASA Authorization Act of 2008.[58] Obama's plan for space exploration includes finishing the station and completion of the US programmes related to the Orion spacecraft.[59] End of mission This section is an excerpt from International Space Station § End of mission.[edit] Many ISS resupply spacecraft have already undergone atmospheric re-entry, such as Jules Verne ATV. According to the Outer Space Treaty, the United States and Russia are legally responsible for all modules they have launched.[60] Several possible disposal options were considered: Natural orbital decay with random reentry (as with Skylab), boosting the station to a higher altitude (which would delay reentry), and a controlled targeted de-orbit to a remote ocean area.[61] In late 2010, the preferred plan was to use a slightly modified Progress spacecraft to de-orbit the ISS.[62] This plan was seen as the simplest, cheapest and with the highest margin of safety.[clarify][62] OPSEK was previously intended to be constructed of modules from the Russian Orbital Segment after the ISS is decommissioned. The modules under consideration for removal from the current ISS included the Multipurpose Laboratory Module (Nauka), launched in July 2021, and the other new Russian modules that are proposed to be attached to Nauka. These newly launched modules would still be well within their useful lives in 2024.[63] At the end of 2011, the Exploration Gateway Platform concept also proposed using leftover USOS hardware and Zvezda 2 as a refuelling depot and service station located at one of the Earth–Moon Lagrange points. However, the entire USOS was not designed for disassembly and will be discarded.[64] On 30 September 2015, Boeing's contract with NASA as prime contractor for the ISS was extended to 30 September 2020. Part of Boeing's services under the contract related to extending the station's primary structural hardware past 2020 to the end of 2028.[65] There have also been suggestions in the commercial space industry that the station could be converted to commercial operations after it is retired by government entities.[66] In July 2018, the Space Frontier Act of 2018 was intended to extend operations of the ISS to 2030. This bill was unanimously approved in the Senate, but failed to pass in the U.S. House.[67][68] In September 2018, the Leading Human Spaceflight Act was introduced with the intent to extend operations of the ISS to 2030, and was confirmed in December 2018.[69][70][71] Congress later passed similar provisions in its CHIPS and Science Act, signed into law by President Joe Biden on 9 August 2022.[72][73] In January 2022, NASA announced a planned date of January 2031 to de-orbit the ISS using a deorbit module and direct any remnants into a remote area of the South Pacific Ocean.[74] New partners China has reportedly expressed interest in the project, especially if it would be able to work with the RKA. Due to national security concerns, the United States Congress passed a law prohibiting contact between US and Chinese space programmes.[75] As of 2019, China is not involved in the International Space Station.[76] In addition to national security concerns, United States objections include China's human rights record and issues surrounding technology transfer.[77][78] The heads of both the South Korean and Indian space agencies announced at the first plenary session of the 2009 International Astronautical Congress on 12 October that their nations intend to join the ISS programme. The talks began in 2010, and were not successful. The heads of agency also expressed support for extending ISS lifetime.[79] European countries not a part of the International Space Station programme will be allowed access to the station in a three-year trial period, ESA officials say.[80] The Indian Space Research Organisation has made it clear that it will not join the ISS and will instead build its own space station.[81] Cost This section is an excerpt from International Space Station § Cost.[edit] The ISS has been described as the most expensive single item ever constructed.[82] As of 2010, the total cost was US$150 billion. This includes NASA's budget of $58.7 billion ($89.73 billion in 2021 dollars) for the station from 1985 to 2015, Russia's $12 billion, Europe's $5 billion, Japan's $5 billion, Canada's $2 billion, and the cost of 36 shuttle flights to build the station, estimated at $1.4 billion each, or $50.4 billion in total. Assuming 20,000 person-days of use from 2000 to 2015 by two- to six-person crews, each person-day would cost $7.5 million, less than half the inflation-adjusted $19.6 million ($5.5 million before inflation) per person-day of Skylab." (wikipedia.org) "The project to create the International Space Station required the utilization and/or construction of new and existing manufacturing facilities around the world, mostly in the United States and Europe. The agencies overseeing the manufacturing involved NASA, Roscosmos, the European Space Agency, JAXA, and the Canadian Space Agency. Hundreds of contractors[1] working for the five space agencies were assigned the task of fabricating the modules, trusses, experiments and other hardware elements for the station. The fact that the project involved the co-operation of sixteen countries working together created engineering challenges that had to be overcome: most notably the differences in language, culture and politics, but also engineering processes, management, measuring standards and communication; to ensure that all elements connect together and function according to plan. The ISS agreement program also called for the station components to be made highly durable and versatile — as it is intended to be used by astronauts indefinitely. A series of new engineering and manufacturing processes and equipment were developed, and shipments of steel, aluminium alloys and other materials were needed for the construction of the space station components. History and planning The project began as Space Station Freedom, a US only effort, but was long delayed by funding and technical problems. Following the initial 1980's authorization (with an intended ten year construction period) by Ronald Reagan, the Station Freedom concept was designed and renamed in the 1990s to reduce costs and expand international involvement. In 1993, the United States and Russia agreed to merge their separate space station plans into a single facility integrating their respective modules and incorporating contributions from the European Space Agency and Japan.[2] In later months, an international agreement board recruited several more space agencies and companies to collaborate to the project. The International Organization for Standardization played a crucial role in unifying and overcoming different engineering methods (such as measurements and units), languages, standards and techniques to ensure quality, engineering communication and logistical management across all manufacturing activities of the station components.[citation needed] Engineering designs Engineering diagrams of various elements of the ISS, with annotations of various parts and systems on each module. Technical schematics     Manufacturing Information and Processes List of factories and manufacturing processes used in the construction and fabrication of the International Space Station modular components: Space Station component     Overseeing agency and contractor(s)     Manufacturing facility     Materials used     Manufacturing date     Mass (kg)     Manufacturing Processes     Factory view Zarya (FGB)[3]     NASA, Roscosmos     Nauka (MLM) European Robotic Arm[22]     Roscosmos     Khrunichev State Research and Production Space Center     Same as Zarya     2005/18     20,300     Same as Zarya, with additions     MLM Nauka 1.jpg Prichal     Roscosmos     RKK Energia     Khrunichev State Research and Production Space Center         2017/20             Mockup of Prichal Module.jpg Space Station component     Overseeing agency and contractor(s)     Manufacturing facility     Materials used     Manufacturing date     Mass (kg)     Manufacturing Processes     Factory view Decommissioned Components are shown in gray. Transportation The European Columbus module being unloaded from the Airbus Beluga at the Shuttle Landing Facility Node 2 inside its transportation container on its way by road to the SSPF, past the Vehicle Assembly Building from the SLF runway Once manufactured or fabricated sufficiently, most of the space station elements were transported by aircraft (usually the Airbus Beluga or the Antonov An-124) to the Kennedy Space Center Space Station Processing Facility for final manufacturing stages, checks and launch processing. Some elements arrived by ship at Port Canaveral.[23][24] Each module for aircraft transport was safely housed in a custom-designed shipping container with foam insulation and an outer shell of sheet metal, to protect it from damage and the elements. At their respective European, Russian and Japanese factories, the modules were transported to their nearest airport by road in their containers, loaded into the cargo aircraft and were flown to Kennedy Space Center's Shuttle Landing Facility for unloading and final transfers to the SSPF and or the Operations and Checkout Building in the KSC industrial area. The American and Canadian-built components such as the US lab, Node 1, Quest airlock, truss and solar array segments, and the Canadarm-2 were either flown by the Aero Spacelines Super Guppy to KSC, or transported by road and rail.[25] After final stages of manufacturing, systems testing and launch checkout, all ISS components are loaded into a payload transfer container in the shape of the Space Shuttle payload bay. This container safely carries the component in its launch configuration until it is hoisted vertically at the launch pad gantry for transfer to the Space Shuttle orbiter for launch and in-orbit assembly of the International Space Station.[26] With the exception of all but one Russian-built module — Rassvet, all ISS components end up here at either one or both of these buildings at Kennedy Space Center. Space Station Processing Facility At the SSPF, ISS modules, trusses and solar arrays are prepped and made ready for launch. In this iconic building are two large 100,000 class clean work environment areas.[27] Workers and engineers wear full non-contaminant clothing while working. Modules receive cleaning and polishing, and some areas are temporarily disassembled for the installation of cables, electrical systems and plumbing. Steel truss parts and module panels are assembled together with screws, bolts and connectors, some with insulation. In another area, shipments of spare materials are available for installation. International Standard Payload Rack frames are assembled and welded together, allowing the installation of instruments, machines and science experiment boxes to be fitted. Once racks are fully assembled, they are hoisted by a special manually operated robotic crane and carefully maneuvered into place inside the space station modules. Each rack weighs from 700 to 1,100 kg, and connect inside the module on special mounts with screws and latches.[28] Cargo bags for MPLM modules were filled with their cargo such as food packages, science experiments and other miscellaneous items on-site in the SSPF, and were loaded into the module by the same robotic crane and strapped in securely.     Overview of the SSPF factory floor filled with space station modules     Overview of the SSPF factory floor filled with space station modules     ExPRESS logistics carrier assembly     ExPRESS logistics carrier assembly     Workers in protective clothing inspect and clean the interior of Node 3     Workers in protective clothing inspect and clean the interior of Node 3     ISPR rack configuration in a typical module     ISPR rack configuration in a typical module     Robotic crane arm loading cargo bags in an MPLM     Robotic crane arm loading cargo bags in an MPLM     Workers fitting and inspecting the rack mounts     Workers fitting and inspecting the rack mounts     Workers loading rack covers     Workers loading rack covers     Leonardo MPLM in its housing jig     Leonardo MPLM in its housing jig     Checking and testing the antenna     Checking and testing the antenna     Columbus being hoisted to a manufacturing weigh stand     Columbus being hoisted to a manufacturing weigh stand     A rack being fitted in the Destiny laboratory     A rack being fitted in the Destiny laboratory     A worker assembles parts for the Japanese Experiment Module and its robotic arm     A worker assembles parts for the Japanese Experiment Module and its robotic arm Operations and Checkout Building Adjacent to the Space Station Processing Facility, the Operations and Checkout Building's spacecraft workshop is used for testing of the space station modules in a vacuum chamber to check for leaks which can be repaired on-site. Additionally, systems checking on various electrical elements and machines is conducted. Similar processing operations to the SSPF are conducted in this building if the SSPF area is full, or certain stages of preparation can only be done in the O&C." (wikipedia.org) "The process of assembling the International Space Station (ISS) has been under way since the 1990s. Zarya, the first ISS module, was launched by a Proton rocket on 20 November 1998. The STS-88 Space Shuttle mission followed two weeks after Zarya was launched, bringing Unity, the first of three node modules, and connecting it to Zarya. This bare 2-module core of the ISS remained uncrewed for the next one and a half years, until in July 2000 the Russian module Zvezda was launched by a Proton rocket, allowing a maximum crew of three astronauts or cosmonauts to be on the ISS permanently. The ISS has a pressurized volume of approximately 1,000 cubic metres (35,000 cu ft), a mass of approximately 410,000 kilograms (900,000 lb), approximately 100 kilowatts of power output, a truss 108.4 metres (356 ft) long, modules 74 metres (243 ft) long, and a crew of seven.[1] Building the complete station required more than 40 assembly flights. As of 2020, 36 Space Shuttle flights delivered ISS elements. Other assembly flights consisted of modules lifted by the Falcon 9, Russian Proton rocket or, in the case of Pirs and Poisk, the Soyuz-U rocket. Some of the larger modules include:     Zarya (launched 20 November 1998)     Unity Module (launched 4 December 1998, also known as Node 1)     Zvezda (launched 12 July 2000)     Destiny Laboratory Module (launched 7 February 2001)     Harmony Module (launched 23 October 2007, also known as Node 2)     Columbus orbital facility (launched 7 February 2008)     Japanese Experiment Module, also known as Kibō (launched in multiple flights between 2008–2009)     The truss, original and iROSA solar panels are also a large part of the station. (launched in multiple flights between 2000–2009)     Nauka (MLM-U) (launched 21 July 2021) Logistics International Space Station mockup at Johnson Space Center in Houston, Texas. The space station is located in orbit around the Earth at an altitude of approximately 410 km (250 mi), a type of orbit usually termed low Earth orbit (the actual height varies over time by several kilometers due to atmospheric drag and reboosts). It orbits Earth in a period of about 90 minutes; by August 2007 it had completed more than 50,000 orbits since launch of Zarya on 20 November 1998. A total of 14 main pressurized modules were scheduled to be part of the ISS by its completion date in 2010.[2] A number of smaller pressurized sections will be adjunct to them (Soyuz spacecraft (permanently 2 as lifeboats – 6 months rotations), Progress transporters (2 or more), the Quest and Pirs airlocks, as well as periodically the H-II Transfer Vehicle). The US Orbital Segment was completed in 2011 after the installation of the Alpha Magnetic Spectrometer during the STS-134 mission. The Russian Orbital Segment assembly has been on an indefinite hiatus since the installation of the Rassvet module in 2010 during the STS-132 mission. The Rassvet module on the ISS right now was originally supposed to be the on-ground dynamic testing mock-up of the now-cancelled Science Power Platform. The Nauka science laboratory module contains new crew quarters, life support equipment that can produce oxygen and water, and a new galley. The Nauka was originally supposed to be delivered to the ISS in 2007 but cost overruns and quality control problems delayed it for over a decade. The Nauka module finally launched in July 2021 and docked to the nadir port of Zvezda module after several days of free flight [3] followed by the Prichal which launched on 24 November 2021. There are plans to add 2 or 3 more modules that would attach to Prichal during the mid-2020s. Adding more Russian modules will help the Zvezda module greatly because Zvezda's originally installed central command computers no longer work (three ThinkPad laptops are now the Zvezda's central command computers) and its Elektron oxygen generators are not replaceable and failed again for a short time in 2020 after multiple malfunctions throughout their history. [4]In Russian modules all the hardware is launched with the equipment permanently installed. It is impossible to replace hardware like in the US Orbital Segment with its very wide 51 inch (105 cm) hatch openings between modules. This potential problem with the Zvezda was made apparent when in October 2020 the toilet, oven, and Elektron all malfunctioned at the same time and the cosmonauts onboard had to make emergency repairs.[5] The ISS, when completed, will consist of a set of communicating pressurized modules connected to a truss, on which four large pairs of photovoltaic modules (solar panels) are attached. The pressurized modules and the truss are perpendicular: the truss spanning from starboard to port and the habitable zone extending on the aft-forward axis. Although during the construction the station attitude may vary, when all four photovoltaic modules are in their definitive position the aft-forward axis will be parallel to the velocity vector.[6] In addition to the assembly and utilization flights, approximately 30 Progress spacecraft flights are required to provide logistics until 2010. Experimental equipment, fuel and consumables are and will be delivered by all vehicles visiting the ISS: the SpaceX Dragon, the Russian Progress, the European ATV and the Japanese HTV, and space station downmass will be carried back to Earth facilities on the Dragon.[7] Columbia disaster and changes in construction plans Columbia lifting off on its final mission. Disaster and consequences 10 March 2001 – The Leonardo Multi-Purpose Logistics Module rests in Space Shuttle Discovery's payload bay during STS-102. After the Space Shuttle Columbia disaster on 1 February 2003, there was some uncertainty over the future of the ISS. The subsequent two and a half-year suspension of the U.S. Space Shuttle program, followed by problems with resuming flight operations in 2005, were major obstacles.[citation needed] The Space Shuttle program resumed flight on 26 July 2005, with the STS-114 mission of Discovery. This mission to the ISS was intended both to test new safety measures implemented since the Columbia disaster and deliver supplies to the station. Although the mission succeeded safely, it was not without risk; foam was shed by the external tank, leading NASA to announce future missions would be grounded until this issue was resolved.[citation needed] Between the Columbia disaster and the resumption of Shuttle launches, crew exchanges were carried out solely using the Russian Soyuz spacecraft. Starting with Expedition 7, two-astronaut caretaker crews were launched in contrast to the previously launched crews of three. Because the ISS had not been visited by a shuttle for an extended period, a larger than planned amount of waste accumulated, temporarily hindering station operations in 2004. However Progress transports and the STS-114 shuttle flight took care of this problem.[citation needed] Changes in construction plans Construction of the International Space Station over New Zealand. Many changes were made to the originally planned ISS, even before the Columbia disaster. Modules and other structures were cancelled or replaced, and the number of Shuttle flights to the ISS was reduced from previously planned numbers. However, more than 80% of the hardware intended to be part of the ISS in the late 1990s was orbited and is now part of the ISS's configuration.[citation needed] During the shuttle stand-down, construction of the ISS was halted and the science conducted aboard was limited due to the crew size of two, adding to earlier delays due to Shuttle problems and the Russian space agency's budget constraints.[citation needed] In March 2006, a meeting of the heads of the five participating space agencies accepted the new ISS construction schedule that planned to complete the ISS by 2010.[8] As of May 2009, a crew of six has been established following 12 Shuttle construction flights after the second "Return to Flight" mission STS-121. Requirements for stepping up the crew size included enhanced environmental support on the ISS, a second Soyuz permanently docked on the station to function as a second 'lifeboat', more frequent Progress flights to provide double the amount of consumables, more fuel for orbit raising maneuvers, and a sufficient supply line of experimental equipment.[citation needed] As of November 2020, the crew capacity has increased to seven due to the launch of Crew Dragon by SpaceX, which can carry 4 astronauts to the ISS. Later additions included the Bigelow Expandable Activity Module (BEAM) in 2016, and numerous Russian components are planned as part of the in-orbit construction of OPSEK.[citation needed] Assembly sequence ISS elements Structure of the International Space Station in mid-December 2022, before the fourth iROSA installation [needs update] The ISS is made up of 16 pressurized modules: six Russian modules (Zarya, Zvezda, Poisk, Rassvet, Nauka, and Prichal), eight US modules (BEAM,[9] Leonardo, Harmony, Quest, Tranquility, Unity, Cupola, and Destiny), one Japanese module (Kibō) and one European module (Columbus). At least one Russian pressurized module (Pirs) is deorbited till now.[10] Although not permanently docked with the ISS, Multi-Purpose Logistics Modules (MPLMs) formed part of the ISS during some Shuttle missions. An MPLM was attached to Harmony (initially to Unity) and was used for resupply and logistics flights.[citation needed] Spacecraft attached to the ISS also extend the pressurized volume. At least one Soyuz spacecraft is always docked as a 'lifeboat' and is replaced every six months by a new Soyuz as part of crew rotation. Table below shows the sequence in which these components were added to the ISS.[11] Decommissioned and deorbited Modules are shown in gray. Element     Assembly flight     Launch date     Launch vehicle     Length     Diameter     Mass     Isolated View     Station View Zarya (FGB)     1A/R     1998-11-20     Proton-K     12.56 m (41.2 ft)     4.1 m (13 ft)     24,968 kg (55,045 lb)     Zarya from STS-88.jpg     Zarya from STS-88.jpg Unity (Node 1)     2A     1998-12-04     Space Shuttle Endeavour (STS-88)     5.5 m (18 ft)     4.3 m (14 ft)     11,895 kg (26,224 lb)     ISS Unity module.jpg     Sts088-703-019e.jpg PMA-1     1.86 m (6 ft 1 in)     1.9 m (6 ft 3 in)     1,589 kg (3,503 lb)     PMA-3 arrives in SSPF.jpg PMA-2     1.86 m (6 ft 1 in)     1.9 m (6 ft 3 in)     1,376 kg (3,034 lb)     PMA-3 arrives in SSPF.jpg Zvezda (Service Module)     1R     2000-07-12     Proton-K     13.1 m (43 ft)     4.2 m (14 ft)     24,604 kg (54,243 lb)     View of the bottom of Zvezda.jpg     Unity-Zarya-Zvezda STS-106.jpg Z1 Truss     3A     2000-10-11     Space Shuttle Discovery (STS-92)                 ISS Unity and Z1 truss structure from STS-92.jpg     S97e5009.jpg PMA-3     1.86 m (6 ft 1 in)     1.9 m (6 ft 3 in)     1,183 kg (2,608 lb)     PMA-3 arrives in SSPF.jpg P6 Truss & Solar Arrays     4A     2000-11-30     Space Shuttle Endeavour (STS-97)                 STS-97 ISS.jpg     STS-97 ISS.jpg Destiny (US Laboratory)     5A     2001-02-07     Space Shuttle Atlantis (STS-98)     9.2 m (30 ft)     4.3 m (14 ft)     14,515 kg (32,000 lb)     ISS Destiny Lab.jpg     Sts098-312-0020.jpg ESP-1     5A.1     2001-03-08     Space Shuttle Discovery (STS-102)                 STS-102 External Storage Platform 1 crop.jpg     S102e5350.jpg Canadarm2 (SSRMS)     6A     2001-04-19     Space Shuttle Endeavour (STS-100)                 STS-114 Steve Robinson on Canadarm2.jpg     S100e5958 cropped.jpg Quest (Joint Airlock)     7A     2001-07-12     Space Shuttle Atlantis (STS-104)     5.5 m (18 ft)     4.0 m (13.1 ft)     9,923 kg (21,876 lb)     ISS Quest airlock.jpg     ISS on 20 August 2001.jpg Pirs (Docking Compartment)     4R     2001-09-14     Soyuz-U (Progress M-SO1)     4.9 m (16 ft)     2.55 m (8.4 ft)     3,838 kg (8,461 lb)     Pirs docking module taken by STS-108.jpg     S108e5628.jpg S0 Truss[12]     8A     2002-04-08     Space Shuttle Atlantis (STS-110)                 S0 Truss lifted from Shuttles cargo bay.jpg     International Space Station.jpg Mobile Base System     UF2     2002-06-05     Space Shuttle Endeavour (STS-111)                 STS-111 Installation of Mobile Base System.jpg     Sts111-711-005.jpg S1 Truss     9A     2002-10-07     Space Shuttle Atlantis (STS-112)                 ISS S1 Truss.jpg     S112e05823.jpg P1 Truss     11A     2002-11-23     Space Shuttle Endeavour (STS-113)                 ISS Truss structure.jpg     ISS Mission STS-113.jpg ESP-2     LF1     2005-07-26     Space Shuttle Discovery (STS-114)                 STS-114 External Storage Platform 2 crop.jpg     ISS Aug2005.jpg P3/P4 Truss & Solar Arrays[13]     12A     2006-09-09     Space Shuttle Atlantis (STS-115)                 STS-115 EVA 2 on Day 5.jpg     STS-115 ISS after undocking.jpg P5 Truss[14]     12A.1     2006-12-09     Space Shuttle Discovery (STS-116)                 STS-116 - ISS P5 Truss awaits installation (NASA ISS014-E-09479).jpg     ISS after STS-116 in December 2006.jpg S3/S4 Truss & Solar Arrays     13A     2007-06-08     Space Shuttle Atlantis (STS-117)                 S3-S4 Truss Installed 2.jpg     ISS after STS-117 in June 2007.jpg S5 Truss     13A.1     2007-08-08     Space Shuttle Endeavour (STS-118)                 STS-116 - P5 Truss hand-off to ISS (NASA S116-E-05765).jpg     ISS after STS-118 in August 2007.jpg ESP-3                 STS-118 ESP-3 on RMS.jpg Harmony (Node 2)     10A     2007-10-23     Space Shuttle Discovery (STS-120)     7.2 m (24 ft)     4.4 m (14 ft)     14,300 kg (31,500 lb)     Harmony Relocation.jpg     ISS after STS-120 in November 2007.jpg Relocation of P6 Truss                 S6 Truss Transfer (STS-119).jpg Columbus (European Laboratory)[15]     1E     2008-02-07     Space Shuttle Atlantis (STS-122)     7 m (23 ft)     4.5 m (15 ft)     12,800 kg (28,219 lb)     Columbus module - cropped.jpg     STS-122 ISS Flyaround.jpg Dextre (SPDM)     1J/A     2008-03-11     Space Shuttle Endeavour (STS-123)                 S123 Dextre01.jpg     STS-123 ISS Flyaround cropped.jpg Experiment Logistics Module (ELM)     4.21 m (13.8 ft)     4.39 m (14.4 ft)     8,386 kg (18,488 lb)     Kibo ELM-PS on ISS.jpg JEM Pressurized Module (JEM-PM)[16][17]     1J     2008-05-31     Space Shuttle Discovery (STS-124)     11.19 m (36.7 ft)     4.39 m (14.4 ft)     15,900 kg (35,100 lb)     STS-124 Kibo.jpg     ISS after STS-124 06 2008.jpg JEM Remote Manipulator System (JEMRMS)             S6 Truss & Solar Arrays     15A     2009-03-15     Space Shuttle Discovery (STS-119)                 S6 Truss Transfer (STS-119).jpg     ISS March 2009.jpg Kibo Exposed Facility (JEM-EF)     2J/A     2009-07-15     Space Shuttle Endeavour (STS-127)                 STS-127 JEM-EF.jpg     ISS & Endeavour Shadow STS-127 2.jpg Poisk (MRM-2)[18][19]     5R     2009-11-10     Soyuz-U (Progress M-MIM2)                 Poisk.Jpeg     STS-129 Atlantis approaches below the ISS.jpg ELC-1     ULF3     2009-11-16     Space Shuttle Atlantis (STS-129)                 ELC2 STS 129.JPG     ISS ULF3 STS-129.jpg ELC-2                 ELC2 STS 129.JPG Tranquility (Node 3)     20A     2010-02-08     Space Shuttle Endeavour (STS-130)     6.706 m (22.00 ft)     4.48 m (14.7 ft)     19,000 kg (42,000 lb)     Tranquility-node3.JPG     ISSpoststs130.jpg Cupola                 Exterior of Cupola - Exp28.jpg Rassvet (MRM-1)[20]     ULF4     2010-05-14     Space Shuttle Atlantis (STS-132)                 STS-132 ISS-23 Rassvet Pirs and Progress M-05M.jpg     International Space Station after undocking of STS-132.jpg Nauka Science Airlock             Nauka RTOd Radiator             ERA portable workpost             Leonardo (PMM)     ULF5     2011-02-24     Space Shuttle Discovery (STS-133)     6.6 m (22 ft)     4.57 m (15.0 ft)     4,082 kg (8,999 lb)     STS-133 ISS-26 Permanent Multipurpose Module.jpg     STS-133 International Space Station after undocking.jpg ELC-4                 ELC2 STS 129.JPG AMS-02     ULF6     2011-05-16     Space Shuttle Endeavour (STS-134)                 Alpha Magnetic Spectrometer - 02.jpg     STS-134 International Space Station after undocking.jpg OBSS                 STS-120 OBSS repair.jpg ELC-3                 ELC2 STS 129.JPG HRSGF     CRS SpX-2     2013-03-13     Falcon 9 (SpaceX CRS-2)                     BEAM[21]     CRS SpX-8     2016-04-08     Falcon 9 (SpaceX CRS-8)                 Beam-instalation-space-station.jpg     ISS-56 International Space Station fly-around (04).jpg IDA-2[22][23]     CRS SpX-9     2016-07-18     Falcon 9 (SpaceX CRS-9)                 IDA-2 upright.jpg IDA-3[24]     CRS SpX-18     2019-07-25     Falcon 9 (SpaceX CRS-18)                 Bartolomeo[25]     CRS SpX-20     2020-03-06     Falcon 9 (SpaceX CRS-20).                     Nanoracks Bishop Airlock     CRS SpX-21     2020-12-06     Falcon 9 (SpaceX CRS-21)                 Bishop Airlock Module.jpg     iROSA 1 and 2     CRS SpX-22     2021-06-03     Falcon 9 (SpaceX CRS-22)                 ISS-52 Roll Out Solar Array (ROSA) (4).jpg     View of the ISS taken during Crew-2 flyaround (ISS066-E-080651).jpg Nauka (MLM-U)[26]     3R     2021-07-21     Proton-M     13 m (43 ft)     4.25 m (13.9 ft)     20,300 kg (44,800 lb)     Nauka Module as seen from Cupola during VKD-51 spacewalk.jpg     View of the ISS taken during Crew-2 flyaround (ISS066-E-080300).jpg European Robotic Arm     11.3 m (37 ft)         630 kg (1,390 lb) Nauka SSPA-GM temporary docking adapter             MLM Means of Attachment of Large payloads (LCCS Part)     79P     2021-10-28     Soyuz 2.1a (Progress MS-18)                     Prichal     6R     2021-11-24     Soyuz 2.1b (Progress M-UM)     4.91 m (16.1 ft)     3.3 m (11 ft)     3,890 kg (8,580 lb)     Russian Spacewalkers dwarfed by the Prichal module (cropped).jpg     MLM Means of Attachment of Large payloads (SCCS Part)     82P     2022-10-26     Soyuz 2.1a (Progress MS-21)                     iROSA 3 and 4     CRS SpX-26     2022-11-26     Falcon 9 (SpaceX CRS-26)                 ISS-52 Roll Out Solar Array (ROSA) (4).jpg     Future elements     In January 2021, NASA announced plans to upgrade the station's solar arrays by installing new arrays on top of six of the station's eight existing arrays.[27] Four were delivered in two pairs, each pair aboard SpaceX CRS-22 in June 2021 and SpaceX CRS-26 in November 2022.[28] Two more will be delivered in one pair aboard SpaceX CRS-28.[29]     Axiom Space plans on launching several modules to connect where PMA-2 is currently at as part of the commercial Axiom Station project. At the end of the ISS's life, Axiom Station could be detached from the ISS and continue in orbit as a commercial low orbit platform.[30] Cancelled modules Diagram of the planned ISS circa 1999     Interim Control Module – not needed once Zvezda was launched     ISS Propulsion Module – not needed once Zvezda was launched     Habitation Module (HAB) – With the cancellation of the Habitation Module, sleeping places are now spread throughout the station. There are two in the Russian segment and four in the US segment. It is not necessary to have a separate 'bunk' in space — many visitors just strap their sleeping bag to the wall of a module, get into it and sleep.     Crew Return Vehicle (CRV) – replaced by crewed spacecraft docked to the station at all times (Soyuz, SpaceX Dragon 2)     Centrifuge Accommodations Module (CAM) – would have been attached to Harmony (Node 2)     Nautilus-X Centrifuge Demonstration – If produced, this centrifuge would have been the first in-space demonstration of sufficient scale centrifuge for artificial partial-g effects. It was designed to become a sleep module for the ISS crew.[31]     Science Power Platform (SPP) – power will be provided to the Russian segments partly by the US solar cell platforms     Russian Research Modules (RM1 and RM2) – replaced by single Multipurpose Laboratory Module (Nauka)     Universal Docking Module (UDM) – cancelled along with the Research Modules which were to connect to it     Science Power Module (NEM) – cancelled in April 2021 and used as the core module of the proposed Russian Orbital Service Station (ROSS).[32][33] Unused modules The following module was built, but has not been used in future plans for the ISS as of January 2021.     American Node 4 – Also known as the Docking Hub System (DHS),[34] would allow the station to have more docking ports for visiting vehicles and would allow inflatable habitats and technology demonstrations to be tested as part of the station.[35] Cost The ISS is credited as the most expensive item ever built, costing around $150 billion (USD),[36] making it more expensive than Skylab (costing US$2.2 billion) [37] and Mir (US$4.2 billion)." (wikipedia.org) "The concepts of space stations and space habitats feature in science fiction. The difference between the two is that habitats are larger and more complex structures intended as permanent homes for substantial populations (though generation ships also fit this description, they are usually not considered space habitats as they are heading for a destination[1]), but the line between the two is fuzzy with significant overlap and the term space station is sometimes used for both concepts.[2][3] The first such artificial satellite in fiction was Edward Everett Hale's "The Brick Moon" in 1869,[2][4] a sphere of bricks 61 meters across accidentally launched into orbit around the Earth with people still onboard.[1][5] Space stations Space stations started appearing frequently in science fiction works following the release of the 1949 popular science book The Conquest of Space by Willy Ley, which deals with the subject.[2] They serve several disparate functions in different works. Among these are industry, health benefits due to low gravity, prisons, and means to observe alien worlds.[6] Several early works of the genre focused on space stations in Earth orbit or at Lagrange points as relay stations for interplanetary communication or transportation.[2] Military uses for space stations appear, but being portrayed as a direct threat is comparatively rare.[2][6] Occasionally, the space stations are connected to the planet they are orbiting via a space elevator, a concept which was introduced to science fiction separately by Arthur C. Clarke and Charles Sheffield in 1979.[6] In fiction, space stations were largely superseded by space habitats in the final quarter of the 20th century.[2] Space habitats The first fictional space habitat proper (not counting the unintentional one in "The Brick Moon") was featured in the 1931 novella "The Prince of Space" by Jack Williamson;[1] it is a cylinder 1,520 metres (5,000 ft) long and wide which rotates to create artificial gravity.[7] Besides cylinders, space habitats in fiction also come in the shapes of spheres, wheels, and hollowed-out asteroids, among others. A more unusual depiction is seen in James Blish's 1955 book Earthman, Come Home—as well as the rest of his Cities in Flight series—where they are cities roaming through space.[1] Space habitats featured only intermittently in science fiction until 1977, when Gerard K. O'Neill's speculative non-fiction book The High Frontier: Human Colonies in Space was published and went on to inspire numerous authors.[3][4][7] The works inspired by O'Neill range from utopian to dystopian; the latter foresee a wide variety of problems with space habitats, including dilapidation while humans are still living there, vulnerability to sabotage, and the potential for a wealthy elite in space to exploit the inhabitants of Earth.[7] A recurring theme in these works is tensions between the inhabitants of the habitats and planet-dwellers.[1] Inasmuch as they provide opportunities for telling stories of isolated populations with diverse cultures, space habitats serve the same function in space that islands serve on Earth in earlier speculative fiction,[3] though some science fiction works such as the TV series Star Trek: Deep Space Nine and Babylon 5 take the opposite approach of portraying space habitats as multicultural centres where members of different spacefaring civilizations coexist peacefully." (wikipedia.org) "A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station is an artificial satellite (i.e., a type of orbital spaceflight). Stations must have docking ports to allow other spacecraft to dock to transfer crew and supplies. The purpose of maintaining an orbital outpost varies depending on the program. Space stations have most often been launched for scientific purposes, but military launches have also occurred. Space stations have harboured so far the only long-duration direct human presence in space. After the first station, Salyut 1 (1971), and its tragic Soyuz 11 crew, space stations have been operated consecutively since Skylab (1973), having allowed a progression of long-duration direct human presence in space. Stations have been occupied by consecutive crews since 1987 with the Salyut successor Mir. Uninterrupted occupation of stations has been achieved since the operational transition from the Mir to the ISS, with its first occupation in 2000. The ISS has hosted the highest number of people in orbit at the same time, reaching 13 for the first time during the eleven day docking of STS-127 in 2009. As of 2023, there are two fully operational space stations in low Earth orbit (LEO) – the International Space Station (ISS) and China's Tiangong Space Station (TSS). The ISS has been permanently inhabited since October 2000 with the Expedition 1 crews and the TSS began continuous inhabitation with the Shenzhou 14 crews in June 2022. These stations are used to study the effects of spaceflight on the human body, as well as to provide a location to conduct a greater number and longer length of scientific studies than is possible on other space vehicles. In 2022, the TSS finished its phase 1 construction with the addition of two lab modules: Wentian ("Quest for the Heavens"), launched on 24 July 2022, and Mengtian ("Dreaming of the Heavens") launched on 31 October 2022, joining the ISS as the most recent space station operating in orbit. In July 2022, Russia announced intentions to withdraw from the ISS after 2024 in order to build its own space station.[1] There have been numerous decommissioned space stations, including the USSR's Salyuts, Russia's Mir, NASA's Skylab, and China's Tiangong 1 and Tiangong 2. History See also: List of space stations Starting with the ill-fated flight of the Soyuz 11 crew to Salyut 1, all recent human spaceflight duration records have been set aboard space stations. The duration record for a single spaceflight is 437.75 days, set by Valeri Polyakov aboard Mir from 1994 to 1995.[2] As of 2021, four cosmonauts have completed single missions of over a year, all aboard Mir. The last military-use space station was the Soviet Salyut 5, which was launched under the Almaz program and orbited between 1976 and 1977.[3][4][5] Early concepts The first mention of anything resembling a space station occurred in Edward Everett Hale's 1869 "The Brick Moon".[6] The first to give serious, scientifically grounded consideration to space stations were Konstantin Tsiolkovsky and Hermann Oberth about two decades apart in the early 20th century.[7] In 1929, Herman Potočnik's The Problem of Space Travel was published, the first to envision a "rotating wheel" space station to create artificial gravity.[6] Conceptualized during the Second World War, the "sun gun" was a theoretical orbital weapon orbiting Earth at a height of 8,200 kilometres (5,100 mi). No further research was ever conducted.[8] In 1951, Wernher von Braun published a concept for a rotating wheel space station in Collier's Weekly, referencing Potočnik's idea. However, development of a rotating station was never begun in the 20th century.[7] Salyut, Almaz and Skylab Main articles: Salyut, Almaz, and Skylab The U.S. Skylab station of the 1970s In 1971, the Soviet Union developed and launched the world's first space station, Salyut 1.[9] The Almaz and Salyut series were eventually joined by Skylab, Mir, and Tiangong-1 and Tiangong-2. The hardware developed during the initial Soviet efforts remains in use, with evolved variants comprising a considerable part of the ISS, orbiting today. Each crew member stays aboard the station for weeks or months but rarely more than a year. Early stations were monolithic designs that were constructed and launched in one piece, generally containing all their supplies and experimental equipment. A crew would then be launched to join the station and perform research. After the supplies had been used up, the station was abandoned.[9] The first space station was Salyut 1, which was launched by the Soviet Union on April 19, 1971. The early Soviet stations were all designated "Salyut", but among these, there were two distinct types: civilian and military. The military stations, Salyut 2, Salyut 3, and Salyut 5, were also known as Almaz stations.[10] The civilian stations Salyut 6 and Salyut 7 were built with two docking ports, which allowed a second crew to visit, bringing a new spacecraft with them; the Soyuz ferry could spend 90 days in space, at which point it needed to be replaced by a fresh Soyuz spacecraft.[11] This allowed for a crew to man the station continually. The American Skylab (1973–1979) was also equipped with two docking ports, like second-generation stations, but the extra port was never used. The presence of a second port on the new stations allowed Progress supply vehicles to be docked to the station, meaning that fresh supplies could be brought to aid long-duration missions. This concept was expanded on Salyut 7, which "hard docked" with a TKS tug shortly before it was abandoned; this served as a proof of concept for the use of modular space stations. The later Salyuts may reasonably be seen as a transition between the two groups.[10] Mir and Apollo–Soyuz Main articles: Mir and Apollo–Soyuz Mir station seen in 1998 Unlike previous stations, the Soviet space station Mir had a modular design; a core unit was launched, and additional modules, generally with a specific role, were later added to that. This method allows for greater flexibility in operation, as well as removing the need for a single immensely powerful launch vehicle. Modular stations are also designed from the outset to have their supplies provided by logistical support craft, which allows for a longer lifetime at the cost of requiring regular support launches.[12] International Space Station Main article: International Space Station View of the International Space Station in 2021 The ISS is divided into two main sections, the Russian Orbital Segment (ROS) and the US Orbital Segment (USOS). The first module of the International Space Station, Zarya, was launched in 1998.[13] The Russian Orbital Segment's "second-generation" modules were able to launch on Proton, fly to the correct orbit, and dock themselves without human intervention.[14] Connections are automatically made for power, data, gases, and propellants. The Russian autonomous approach allows the assembly of space stations prior to the launch of crew. The Russian "second-generation" modules are able to be reconfigured to suit changing needs. As of 2009, RKK Energia was considering the removal and reuse of some modules of the ROS on the Orbital Piloted Assembly and Experiment Complex after the end of mission is reached for the ISS.[15] However, in September 2017, the head of Roscosmos said that the technical feasibility of separating the station to form OPSEK had been studied, and there were now no plans to separate the Russian segment from the ISS.[16] In contrast, the main US modules launched on the Space Shuttle and were attached to the ISS by crews during EVAs. Connections for electrical power, data, propulsion, and cooling fluids are also made at this time, resulting in an integrated block of modules that is not designed for disassembly and must be deorbited as one mass.[17] The Axiom Orbital Segment is a planned commercial segment to be added to the ISS starting in the mid-2020s. Axiom Space gained NASA approval for the venture in January 2020. Up to three Axiom modules will attach to the International Space Station. The first module could be launched no later than 2024 and will be docked to the forward port of Harmony, requiring relocation of the PMA-2. Axiom Space plans to attach up to two additional modules to its first core module, and send private astronauts to inhabit the modules. The modules could one day detach into the Axiom Station in a manner similar to Russia's proposed OPSEK.[18] Tiangong program Main articles: Tiangong space station and Tiangong program Rendering of the completed Tiangong Space Station in November 2022 Rendering of the completed Tiangong Space Station in November 2022 China's first space laboratory, Tiangong-1 was launched in September 2011.[19] The uncrewed Shenzhou 8 then successfully performed an automatic rendezvous and docking in November 2011. The crewed Shenzhou 9 then docked with Tiangong-1 in June 2012, followed by the crewed Shenzhou 10 in 2013.[citation needed] According to the China Manned Space Engineering Office, Tiangong-1 reentered over the South Pacific Ocean, northwest of Tahiti, on 2 April 2018 at 00:15 UTC.[20][21] A second space laboratory Tiangong-2 was launched in September 2016, while a plan for Tiangong-3 was merged with Tiangong-2.[22] The station made a controlled reentry on 19 July 2019 and burned up over the South Pacific Ocean.[23] The Tiangong Space Station (Chinese: 天宫; pinyin: Tiāngōng; lit. 'Heavenly Palace'), the first module of which was launched on 29 April 2021,[24] is in low Earth orbit, 340 to 450 kilometres above the Earth at an orbital inclination of 42° to 43°. Its planned construction via 11 total launches across 2021-22 is intended to extend the core module with two laboratory modules, capable of hosting up to six crew.... Architecture Two types of space stations have been flown: monolithic and modular. Monolithic stations consist of a single vehicle and are launched by one rocket. Modular stations consist of two or more separate vehicles that are launched independently and docked on orbit. Modular stations are currently preferred due to lower costs and greater flexibility.[52][53] A space station is a complex vehicle that must incorporate many interrelated subsystems, including structure, electrical power, thermal control, attitude determination and control, orbital navigation and propulsion, automation and robotics, computing and communications, environmental and life support, crew facilities, and crew and cargo transportation. Stations must serve a useful role, which drives the capabilities required.[citation needed] Orbit and purpose Materials Main article: Manufacturing of the International Space Station See also: Bigelow Expandable Activity Module Space stations are made from durable materials that have to weather space radiation, internal pressure, micrometeoroids, and thermal effects of the sun and cold temperatures for very long periods of time. They are typically made from stainless steel, titanium and high-quality aluminum alloys, with layers of insulation such as Kevlar as a ballistics shield protection.[54] The International Space Station has a single inflatable module, the Bigelow Expandable Activity Module, which was installed in April 2016 after being delivered to the ISS on the SpaceX CRS-8 resupply mission.[55][56] This module, based on NASA research in the 1990s, weighed 1,400 kilograms (3,100 lb) and was transported while compressed before being attached to the ISS by the space station arm and inflated to provide a 16 cubic metres (21 cu yd) volume. Whilst it was initially designed for a 2 year lifetime it was still attached and being used for storage in August 2022.[57][58] Construction     Salyut 1 - first space station, launched in 1971     Skylab - launched in a single launch in May 1973     MIR - first modular space station assembled in orbit     International Space Station - modular space station assembled in orbit     Tiangong space station - Chinese space station Habitability Main article: Effect of spaceflight on the human body The space station environment presents a variety of challenges to human habitability, including short-term problems such as the limited supplies of air, water, and food and the need to manage waste heat, and long-term ones such as weightlessness and relatively high levels of ionizing radiation. These conditions can create long-term health problems for space-station inhabitants, including muscle atrophy, bone deterioration, balance disorders, eyesight disorders, and elevated risk of cancer.[59] Future space habitats may attempt to address these issues, and could be designed for occupation beyond the weeks or months that current missions typically last. Possible solutions include the creation of artificial gravity by a rotating structure, the inclusion of radiation shielding, and the development of on-site agricultural ecosystems. Some designs might even accommodate large numbers of people, becoming essentially "cities in space" where people would reside semi-permanently.[60] Molds that develop aboard space stations can produce acids that degrade metal, glass, and rubber. Despite an expanding array of molecular approaches for detecting microorganisms, rapid and robust means of assessing the differential viability of the microbial cells, as a function of phylogenetic lineage, remain elusive.[61] Power Main article: Solar panels on spacecraft See also: Electrical system of the International Space Station and Roll Out Solar Array Like uncrewed spacecraft close to the sun, space stations in the inner Solar System generally rely on solar panels to obtain power.[62] Life support Main articles: Environmental Control and Life Support System and Vika oxygen generator Space station air and water is brought up in spacecraft from Earth before being recycled. Supplemental oxygen can be supplied by a solid fuel oxygen generator.[63] Communications Main articles: Tracking and Data Relay Satellite System, Lira (ISS), and Amateur Radio on the International Space Station See also: Interplanetary Internet, InterPlaNet, and Optical Payload for Lasercomm Science Occupation Space stations have harboured so far the only long-duration direct human presence in space. After the first station, Salyut 1 (1971), and its tragic Soyuz 11 crew, space stations have been operated consecutively since Skylab (1973-1974), having allowed a progression of long-duration direct human presence in space. Long-duration resident crews have been joined by visiting crews since 1977 (Salyut 6), and stations have been occupied by consecutive crews since 1987 with the Salyut successor Mir. Uninterrupted occupation of stations has been achieved since the operational transition from the Mir to the ISS, with its first occupation in 2000. The ISS has hosted the highest number of people in orbit at the same time, reaching 13 for the first time during the eleven day docking of STS-127 in 2009.[64] Operations Resupply and crew vehicles Main article: List of crewed spacecraft Main article: Comparison of space station cargo vehicles See also: Commercial Resupply Services Many spacecraft are used to dock with the space stations. Soyuz flight T-15 in March to July 1986 was the first and as of 2016, only spacecraft to visit two different space stations, Mir and Salyut 7.[65] International Space Station Main articles: List of human spaceflights to the International Space Station and Uncrewed spaceflights to the International Space Station The International Space Station has been supported by many different spacecraft.     Future         Sierra Nevada Corporation Dream Chaser[66][67]         New Space-Station Resupply Vehicle (HTV-X)[68][69]         Roscosmos Orel[70][71]     Current         Northrop Grumman Cygnus (2013-present)[72][73]         Roscosmos Progress (multiple variants) (2000-present)[74][75]         Energia Soyuz (multiple variants) (2001-present)[76][77]         SpaceX Dragon 2 (2020-present)[78][79]     Retired         Automated Transfer Vehicle (ATV) (2008-2015)[80][81]         H-II Transfer Vehicle (HTV) (2009-2020)[82][83]         Space Shuttle (1998-2011)[84][85]         SpaceX Dragon (2012-2020)[86][87] Tiangong space station Main article: Tiangong space station The Tiangong space station is supported by the following spacecraft:     Shenzhou (2021-present)[88][89]     Tianzhou (2021-present)[90][91] Tiangong program Main article: Tiangong program The Tiangong program relied on the following spacecraft.     Shenzhou program (2011-2016)[92][93] Mir Main articles: List of human spaceflights to Mir and List of uncrewed spaceflights to Mir The Mir space station was in orbit from 1986 to 2001 and was supported and visited by the following spacecraft:     Roscosmos Progress (multiple variants) (1986-2000)[94][95] - An additional Progress spacecraft was used in 2001 to deorbit Mir.[96][97]     Energia Soyuz (multiple variants) (1986-2000)[65][98]     Space Shuttle (1995-1998)[99][100] Skylab Main article: Skylab     Apollo command and service module (1973-1974)[101][102] Salyut programme Main article: Salyut programme     Energia Soyuz (multiple variants) (1971–1986)[98][103] Docking and berthing Main article: Docking and berthing of spacecraft See also: International Docking System Standard and Chinese Docking Mechanism Maintenance Research Main article: Scientific research on the International Space Station Research conducted on the Mir included the first long term space based ESA research project EUROMIR 95 which lasted 179 days and included 35 scientific experiments.[104] During the first 20 years of operation of the International Space Station, there were around 3,000 scientific experiments in the areas of biology and biotech, technology development, educational activities, human research, physical science, and Earth and space science.[105][106] Materials research Space stations provide a useful platform to test the performance, stability, and survivability of materials in space. This research follows on from previous experiments such as the Long Duration Exposure Facility, a free flying experimental platform which flew from April 1984 until January 1990.[107][108]     Mir Environmental Effects Payload (1996-1997)[109][110]     Materials International Space Station Experiment (2001-present)[111][112] Human research Main articles: Effect of spaceflight on the human body and Bioastronautics See also: ISS year-long mission Botany Main article: Astrobotany Space tourism Main article: Orbital space tourism On the International Space Station, guests sometimes pay $50 million to spend the week living as an astronaut. Later, space tourism is slated to expand once launch costs are lowered sufficiently. By the end of the 2020s, space hotels may become relatively common.[citation needed] Finance As it currently costs on average $10,000 to $25,000 per kilogram to launch anything into orbit, space stations remain the exclusive province of government space agencies, which are primarily funded via taxation. In the case of the International Space Station, space tourism makes up another chunk of money to run it. Legacy Technology spinoffs See also: NASA spinoff technologies International cooperation Cultural impact This section is an excerpt from Space stations and habitats in fiction.[edit] "The Brick Moon" – an 1869 serial by Edward Everett Hale – was the first fictional space station or habitat. The concepts of space stations and space habitats feature in science fiction. The difference between the two is that habitats are larger and more complex structures intended as permanent homes for substantial populations (though generation ships also fit this description, they are usually not considered space habitats as they are heading for a destination[113]), but the line between the two is fuzzy with significant overlap and the term space station is sometimes used for both concepts.[114][115] The first such artificial satellite in fiction was Edward Everett Hale's "The Brick Moon" in 1869,[114][116] a sphere of bricks 61 meters across accidentally launched into orbit around the Earth with people still onboard.[113][117] Space habitat Main articles: Space habitat and Space habitat (facility) See also: Moonbase and Mars habitat" (wikipedia.org) "Human impact See also: Space debris, Space sustainability, List of artificial objects on the Moon, Space art § Art in space, Moonbase, Lunar resources § Mining, Tourism on the Moon, and Space archaeology Artifacts of human activity, Apollo 17's Lunar Surface Experiments Package[244] While the Moon has the lowest planetary protection target-categorization, its degradation as a pristine body and scientific place has been discussed.[245] If there is astronomy performed from the Moon, it will need to be free from any physical and radio pollution. While the Moon has no significant atmosphere, traffic and impacts on the Moon causes clouds of dust that can spread far and possibly contaminate the original state of the Moon and its special scientific content.[246] Scholar Alice Gorman asserts that, although the Moon is inhospitable, it is not dead, and that sustainable human activity would require treating the Moon's ecology as a co-participant.[247] The so-called "Tardigrade affair" of the 2019 crashed Beresheet lander and its carrying of tardigrades has been discussed as an example for lacking measures and lacking international regulation for planetary protection.[248] Space debris beyond Earth around the Moon has been considered as a future challenge with increasing numbers of missions to the Moon, particularly as a danger for such missions.[249][250] As such lunar waste management has been raised as an issue which future lunar missions, particularly on the surface, need to tackle.[251][252] Beside the remains of human activity on the Moon, there have been some intended permanent installations like the Moon Museum art piece, Apollo 11 goodwill messages, six lunar plaques, the Fallen Astronaut memorial, and other artifacts.[244] Longterm missions continuing to be active are some orbiters such as the 2009-launched Lunar Reconnaissance Orbiter surveilling the Moon for future missions, as well as some Landers such as the 2013-launched Chang'e 3 with its Lunar Ultraviolet Telescope still operational.[253] Five retroreflectors have been installed on the Moon since the 1970s and since used for accurate measurements of the physical librations through laser ranging to the Moon. There are several missions by different agencies and companies planned to establish a longterm human presence on the Moon, with the Lunar Gateway as the currently most advanced project as part of the Artemis program. Astronomy from the Moon Further information: Extraterrestrial sky § The Moon The LCRT concept for a radio telescope on the Moon For many years, the Moon has been recognized as an excellent site for telescopes.[254] It is relatively nearby; astronomical seeing is not a concern; certain craters near the poles are permanently dark and cold, and thus especially useful for infrared telescopes; and radio telescopes on the far side would be shielded from the radio chatter of Earth.[255] The lunar soil, although it poses a problem for any moving parts of telescopes, can be mixed with carbon nanotubes and epoxies and employed in the construction of mirrors up to 50 meters in diameter.[256] A lunar zenith telescope can be made cheaply with an ionic liquid.[257] In April 1972, the Apollo 16 mission recorded various astronomical photos and spectra in ultraviolet with the Far Ultraviolet Camera/Spectrograph.[258] The Moon has been also a site of Earth observation, particularly culturally as in the imagery called Earthrise. Living on the Moon Main article: Lunar habitation Astronaut Buzz Aldrin in life-supporting suit looking back at the first lunar habitat and base, the Lunar Module Eagle of Tranquility Base, during Apollo 11 (1969), the first crewed Moon landing The only instances of humans living on the Moon have taken place in an Apollo Lunar Module for several days at a time (for example, during the Apollo 17 mission).[259] One challenge to astronauts during their stay on the surface is that lunar dust sticks to their suits and is carried into their quarters. Astronauts could taste and smell the dust, calling it the "Apollo aroma".[260] This fine lunar dust can cause health issues.[260] In 2019, at least one plant seed sprouted in an experiment on the Chang'e 4 lander. It was carried from Earth along with other small life in its Lunar Micro Ecosystem.... Cultural representation Further information: Cultural astronomy, Archaeoastronomy, Lunar deity, Selene, Luna (goddess), Crescent, and Man in the Moon See also: Nocturne (painting) and Moon magic Recurring lunar aspects of lunar deities Sumerian cylinder seal and impression, dated c. 2100 BC, of Ḫašḫamer, ensi (governor) of Iškun-Sin c. 2100 BC. The seated figure is probably king Ur-Nammu, bestowing the governorship on Ḫašḫamer, who is led before him by Lamma (protective goddess).[291] The crescent (Nanna/Sîn, c. 2100 BC Luna on the Parabiago plate (2nd–5th century), featuring the crescent crown and chariot lunar aspect found in different cultures. Crescent headgear and chariot (Luna, 2nd–5th century) Rabbits are in a range of cultures identified with the Moon, from China to the Indigenous peoples of the Americas, as with the rabbit (on the left) of the Maya moon goddess (6th–9th century). A Moon rabbit (Mayan moon goddess, 6th–9th century) Since prehistoric and ancient times humans have drawn the Moon and have described a range of understandings of it, having prominent importance in different cosmologies, often exhibiting a spirit, being a deity or an aspect, particularly in astrology. For the representation of the Moon, especially its lunar phases, the crescent symbol (🌙) has been particularly used by many cultures. In writing systems such as Chinese the crescent has developed into the symbol 月, the word for Moon, and in ancient Egyptian it was the symbol 𓇹, which is spelled like the ancient Egyptian lunar deity Iah, meaning Moon.[292] Iconographically the crescent was used in Mesopotamia as the primary symbol of Nanna/Sîn,[293] the ancient Sumerian lunar deity,[294][293] who was the father of Innana/Ishtar, the goddess of the planet Venus (symbolized as the eight pointed Star of Ishtar),[294][293] and Utu/Shamash, the god of the Sun (symbolized as a disc, optionally with eight rays),[294][293] all three often depicted next to each other. Nanna was later known as Sîn,[293][294] and was particularly associated with magic and sorcery.[294] The crescent was further used as an element of lunar deities wearing headgears or crowns in an arrangement reminiscent of horns, as in the case of the ancient Greek Selene[295][296] or the ancient Egyptian Khonsu. Selene is associated with Artemis and paralleled by the Roman Luna, which both are occasionally depicted driving a chariot, like the Hindu lunar deity Chandra. The different or sharing aspects of deities within pantheons has been observed in many cultures, especially by later or contemporary culture, particularly forming triple deities. The Moon in Roman mythology for example has been associated with Juno and Diana, while Luna being identified as their byname and as part of a triplet (diva triformis) with Diana and Proserpina, Hecate being identified as their binding manifestation as trimorphos. The star and crescent (☪️) arrangement goes back to the Bronze Age, representing either the Sun and Moon, or the Moon and planet Venus, in combination. It came to represent the goddess Artemis or Hecate, and via the patronage of Hecate came to be used as a symbol of Byzantium, possibly influencing the development of the Ottoman flag, specifically the combination of the Turkish crescent with a star.[297] Since then the heraldric use of the star and crescent proliferated becoming a popular symbol for Islam (as the hilal of the Islamic calendar) and for a range of nations.[298] In Roman Catholic Marian veneration, the Virgin Mary (Queen of Heaven) has been depicted since the late Middle Ages on a crescent and adorned with stars. In Islam Muhammad is particularly attributed with the Moon through the so-called splitting of the Moon (Arabic: انشقاق القمر) miracle.[299] The contrast between the brighter highlands and the darker maria have been seen by different cultures forming abstract shapes, which are among others the Man in the Moon or the Moon Rabbit (e.g. the Chinese Tu'er Ye or in Indigenous American mythologies, as with the aspect of the Mayan Moon goddess).[291] In Western alchemy silver is associated with the Moon, and gold with the Sun.[300] Modern culture representation See also: Moon in science fiction and List of appearances of the Moon in fiction The Moon is prominently featured in Vincent van Gogh's 1889 painting, The Starry Night (left). An iconic image of the Man in the Moon from the first science-fiction film set in space, A Trip to the Moon (1902), inspired by a history of literature about going to the Moon (right). The perception of the Moon in modern times has been informed by telescope enabled modern astronomy and later by spaceflight enabled actual human activity at the Moon, particularly the culturally impactful lunar landings. These new insights inspired cultural references, connecting romantic reflections about the Moon[301] and speculative fiction such as science-fiction dealing with the Moon.[302][303] Contemporarily the Moon has been seen as a place for economic expansion into space, with missions prospecting for lunar resources. This has been accompanied with renewed public and critical reflection on humanity's cultural and legal relation to the celestial body, especially regarding colonialism,[248] as in the 1970 poem "Whitey on the Moon". In this light the Moon's nature has been invoked,[274] particularly for lunar conservation[250] and as a common.[304][268][276] Lunar effect Main article: Lunar effect The lunar effect is a purported unproven correlation between specific stages of the roughly 29.5-day lunar cycle and behavior and physiological changes in living beings on Earth, including humans. The Moon has long been associated with insanity and irrationality; the words lunacy and lunatic are derived from the Latin name for the Moon, Luna. Philosophers Aristotle and Pliny the Elder argued that the full moon induced insanity in susceptible individuals, believing that the brain, which is mostly water, must be affected by the Moon and its power over the tides, but the Moon's gravity is too slight to affect any single person.[305] Even today, people who believe in a lunar effect claim that admissions to psychiatric hospitals, traffic accidents, homicides or suicides increase during a full moon, but dozens of studies invalidate these claims." (wikipedia.org) "Space architecture is the theory and practice of designing and building inhabited environments in outer space.[1] This mission statement for space architecture was developed at the World Space Congress in Houston in 2002 by members of the Technical Aerospace Architecture Subcommittee of the American Institute of Aeronautics and Astronautics (AIAA). The architectural approach to spacecraft design addresses the total built environment. It is mainly based on the field of engineering (especially aerospace engineering), but also involves diverse disciplines such as physiology, psychology, and sociology. Like architecture on Earth, the attempt is to go beyond the component elements and systems and gain a broad understanding of the issues that affect design success.[2] Space architecture borrows from multiple forms of niche architecture to accomplish the task of ensuring human beings can live and work in space. These include the kinds of design elements one finds in “tiny housing, small living apartments/houses, vehicle design, capsule hotels, and more.”[3] Much space architecture work has been in designing concepts for orbital space stations and lunar and Martian exploration ships and surface bases for the world's space agencies, chiefly NASA. The practice of involving architects in the space program grew out of the Space Race, although its origins can be seen much earlier. The need for their involvement stemmed from the push to extend space mission durations and address the needs of astronauts including but beyond minimum survival needs. Space architecture is currently represented in several institutions. The Sasakawa International Center for Space Architecture (SICSA) is an academic organization with the University of Houston that offers a Master of Science in Space Architecture. SICSA also works design contracts with corporations and space agencies. In Europe, The Vienna University of Technology and the International Space University are involved in space architecture research. The TU Wien offers an EMBA in Space Architecture. The International Conference on Environmental Systems (ICES) meets annually to present sessions on human spaceflight and space human factors. Within the American Institute of Aeronautics and Astronautics (AIAA), the Space Architecture Technical Committee (SATC) has been formed. Despite the historical pattern of large government-led space projects and university-level conceptual design, the advent of space tourism threatens to shift the outlook for space architecture work. Etymology The word space in space architecture is referring to the outer space definition, which is from English outer and space. Outer can be defined as "situated on or toward the outside; external; exterior" and originated around 1350–1400 in Middle English.[4] Space is "an area, extent, expanse, lapse of time," the aphetic of Old French espace dating to 1300. Espace is from Latin spatium, "room, area, distance, stretch of time," and is of uncertain origin.[5] In space architecture, speaking of outer space usually means the region of the universe outside Earth's atmosphere, as opposed to outside the atmospheres of all terrestrial bodies. This allows the term to include such domains as the lunar and Martian surfaces. Architecture, the concatenation of architect and -ure, dates to 1563, coming from Middle French architecte. This term is of Latin origin, formerly architectus, which came from Greek arkhitekton. Arkitekton means "master builder" and is from the combination of arkhi- "chief" and tekton "builder".[6] The human experience is central to architecture – the primary difference between space architecture and spacecraft engineering. There is some debate over the terminology of space architecture. Some consider the field to be a specialty within architecture that applies architectural principles to space applications. Others such as Ted Hall of the University of Michigan see space architects as generalists, with what is traditionally considered architecture (Earth-bound or terrestrial architecture) being a subset of a broader space architecture.[7] Any structures that fly in space will likely remain for some time highly dependent on Earth-based infrastructure and personnel for financing, development, construction, launch, and operation. Therefore, it is a matter of discussion how much of these earthly assets are to be considered part of space architecture. The technicalities of the term space architecture are open to some level of interpretation. Origins Ideas of people traveling to space were first published in science fiction stories, like Jules Verne's 1865 From the Earth to the Moon. In this story several details of the mission (crew of three, spacecraft dimensions, Florida launch site) bear striking similarity to the Apollo Moon landings that took place more than 100 years later. Verne's aluminum capsule had shelves stocked with equipment needed for the journey such as a collapsing telescope, pickaxes and shovels, firearms, oxygen generators, and even trees to plant. A curved sofa was built into the floor and walls and windows near the tip of the spacecraft were accessible by ladder.[8] The projectile was shaped like a bullet because it was gun-launched from the ground, a method infeasible for transporting man to space due to the high acceleration forces produced. It would take rocketry to get humans to the cosmos." (wikipedia.org) "Space Station Freedom was a NASA project to construct a permanently crewed Earth-orbiting space station in the 1980s. Although approved by then-president Ronald Reagan and announced in the 1984 State of the Union address, Freedom was never constructed or completed as originally designed, and after several cutbacks, the project evolved into the International Space Station program. Space Station Freedom was a multinational collaborative project involving four participating space agencies: NASA (United States), NASDA (Japan), ESA (Europe), and CSA (Canada). Original proposal As the Apollo program began to wind down in the late 1960s, there were numerous proposals for what should follow it. Of the many proposals, large and small, three major themes emerged. Foremost among them was a crewed mission to Mars, using systems not unlike the ones used for Apollo. A permanent space station was also a major goal, both to help construct the large spacecraft needed for a Mars mission as well as to learn about long-term operations in space. Finally, a space logistics vehicle was intended to cheaply launch crews and cargo to that station. In the early 1970s, Spiro Agnew took these general plans to President Nixon, who was battling with a major federal budget deficit. When he presented the three concepts, Nixon told him to select one. After much debate, NASA selected the space logistics vehicle, which by this time was already known as the Space Shuttle. They argued that the Shuttle would so lower costs of launching cargo that it would make the construction of the station less expensive. From this point forward these plans were never seriously changed, in spite of dramatic changes to the funding environment and the complete redesign of the Shuttle concept. In the early 1980s, with the Space Shuttle completed, NASA proposed the creation of a large, permanently crewed space station, which then-NASA Administrator James M. Beggs called "the next logical step" in space. In some ways it was meant to be the U.S. answer to the Soviet Mir. NASA plans called for the station, which was later dubbed Space Station Freedom, to function as an orbiting repair shop for satellites, an assembly point for spacecraft, an observation post for astronomers, a microgravity laboratory for scientists, and a microgravity factory for companies. Reagan announced plans to build Space Station Freedom in 1984, stating: "We can follow our dreams to distant stars, living and working in space for peaceful economic and scientific gain." Design iterations Following the presidential announcement, NASA began a set of studies to determine the potential uses for the space station, both in research and in industry, in the U.S. or overseas. This led to the creation of a database of thousands of possible missions and payloads; studies were also carried out with a view to supporting potential planetary missions, as well as those in low Earth orbit. Several Space Shuttle missions in the 1980s and early 1990s included spacewalks to demonstrate and test space station construction techniques. After the establishment of the initial baseline design, the project evolved extensively, growing in scope and cost. "Power Tower" (1984) "Power Tower" space station concept (1984) In April 1984, the newly established Space Station Program Office at Johnson Space Center produced a first reference configuration; this design would serve as a baseline for further planning. The chosen design was the "Power Tower", a long central keel with most mass located at either end. This arrangement would provide enough gravity gradient stability to keep the station aligned with the keel pointed towards the Earth, reducing the need for thruster firings. Most designs featured a cluster of modules at the lower end and a set of articulated solar arrays at the upper end. It also contained a servicing bay. In April 1985, the program selected a set of contractors to carry out definition studies and preliminary design; various trade-offs were made in this process, balancing higher development costs against reduced long-term operating costs. Revised Baseline Configuration (1987) Revised Baseline Configuration (1987) At the same time, late 1986, NASA carried out a study into new configuration options to reduce development costs; options studied ranged from the use of a Skylab-type station to a phased development of the Dual-Keel configuration. This approach involved splitting assembly into two phases; Phase 1 would provide the central modules, and the transverse boom, but with no keels. The solar arrays would be augmented to ensure 75 kW of power would be provided, and the polar platform and servicing facility were again deferred. The study concluded that the project was viable, reducing development costs while minimizing negative impacts, and it was designated the Revised Baseline Configuration. This would have a development cost of US$15.3 billion (in FY1989 dollars) and FEL in the first quarter of 1994. This replanning was endorsed by the National Research Council in September 1987, which also recommended that the long-term national goals should be studied before committing to any particular Phase 2 design. During 1986 and 1987, various other studies were carried out on the future of the U.S. space program; the results of these often impacted the Space Station, and their recommendations were folded into the revised baseline as necessary. One of the results of these was to baseline the Station program as requiring five shuttle flights a year for operations and logistics, rotating four crew at a time with the aim of extending individual stay times to 180 days. Freedom (1988) to Alpha (1993) 1991 artist's conception of the completed Space Station Freedom in orbit. NASA signed final ten-year contracts for developing the Space Station in September 1988, and the project was finally moving into the hardware fabrication phase. The Space Station Freedom design was slightly modified in late 1989 after the program's Fiscal 1990 budget again was reduced — from $2.05 billion to $1.75 billion — when the design was found to be 23% overweight and over budget, too complicated to assemble, and providing little power for its users. The 1990 Space Exploration Initiative called for the construction of the Space Station Freedom. Congress consequently demanded yet another redesign in October 1990, and requested further cost reductions after the fiscal 1991 budget was cut from $2.5 billion to $1.9 billion. NASA unveiled its new space station design in March 1991. Repeated budget cuts had forced a postponement of the first launch by a year, to March 1995. The Station would be permanently crewed from June 1997 onwards, and completed in February 1998. In 1993, after more calls for the station to be redesigned again to reduce costs and include more international involvement,[1] the option that became known as Space Station 'Alpha' was chosen (from three competing concepts),[2][3] using 75 percent of the hardware designs originally intended for the Freedom program.[4] Cost escalation of the project and financial difficulties in Russia led to a briefing between NASA and NPO Energia on Mir-2 that same year, resulting in an option known briefly as the Russian Alpha (RAlpha).[5] In late 1993, Freedom, Mir-2, and the European and Japanese modules were incorporated into a single International Space Station Alpha (ISSA), with Alpha dropped from the name internally by early 1995.[6] In July 1995, the International Space Station Authorization Act of 1995 House report to U.S.Congress was released and the names Freedom, Alpha, and ISSA were no more.[7] By this time, the hardware meant for Space Station Freedom, then Alpha, that had already been designed and built or was in development, around 10 percent, became part of the ISS. Station program placed on hold Underestimates by NASA of the station program's cost and unwillingness by the U.S. Congress to appropriate funding for the space station resulted in delays of Freedom's design and construction; it was regularly redesigned and re-scoped. Between 1984 and 1993 it went through seven major re-designs, losing capacity and capabilities each time. Rather than being completed in a decade, as Reagan had predicted, Freedom was never built, and no Shuttle launches were made as part of the program. By 1993, Freedom was politically unviable; the administration had changed, and Congress was tiring of paying yet more money into the station program. In addition, there were open questions over the need for the station. Redesigns had cut most of the science capacity by this point, and the Space Race had ended in 1975 with the Apollo-Soyuz Test Project. NASA presented several options to President Clinton, but even the most limited of these was still seen as too expensive. In June 1993, an amendment to remove space station funding from NASA's appropriations bill failed by one vote in the House of Representatives.[8] That October, a meeting between NASA and the Russian Space Agency agreed to the merger of the projects into what would become the International Space Station. The merger of the project faced opposition by representatives such as Tim Roemer who feared Russia would break the Missile Technology Control Regime agreement and felt the program was far too costly.[9] Proposed bills did not pass Congress. Conversion to the International Space Station Main article: International Space Station International Space Station in May 2011 In 1993, the Clinton administration announced the transformation of Space Station Freedom into the International Space Station (ISS). NASA Administrator Daniel Goldin supervised the addition of Russia to the project. To accommodate reduced budgets, the station design was scaled back from 508 to 353 square feet (47 to 33 m²), the crew capacity of the NASA-provided part was reduced from 7 to 3 (while the complete station is crewed by 6 but may be increased to 7[10]), and the station's functions were reduced.[11] Its first component was launched into orbit in 1998,[12] with the first long-term residents arriving in November 2000." (wikipedia.org) "The Solar System[c] is the gravitationally bound system of the Sun and the objects that orbit it. It formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The vast majority (99.86%) of the system's mass is in the Sun, with most of the remaining mass contained in the planet Jupiter. The planetary system around the Sun contains eight planets. The four inner system planets—Mercury, Venus, Earth and Mars—are terrestrial planets, being composed primarily of rock and metal. The four giant planets of the outer system are substantially larger and more massive than the terrestrials. The two largest, Jupiter and Saturn, are gas giants, being composed mainly of hydrogen and helium; the next two, Uranus and Neptune, are ice giants, being composed mostly of volatile substances with relatively high melting points compared with hydrogen and helium, such as water, ammonia, and methane. All eight planets have nearly circular orbits that lie near the plane of Earth's orbit, called the ecliptic. There are an unknown number of smaller dwarf planets and innumerable small Solar System bodies orbiting the Sun.[d] Six of the major planets, the six largest possible dwarf planets, and many of the smaller bodies are orbited by natural satellites, commonly called "moons" after Earth's Moon. Two natural satellites, Jupiter's moon Ganymede and Saturn's moon Titan, are larger than Mercury, the smallest terrestrial planet, though less massive, and Jupiter's moon Callisto is nearly as large. Each of the giant planets and some smaller bodies are encircled by planetary rings of ice, dust and moonlets. The asteroid belt, which lies between the orbits of Mars and Jupiter, contains objects composed of rock, metal and ice. Beyond Neptune's orbit lie the Kuiper belt and scattered disc, which are populations of objects composed mostly of ice and rock. In the outer reaches of the Solar System lies a class of minor planets called detached objects. There is considerable debate as to how many such objects there will prove to be.[9] Some of these objects are large enough to have rounded under their own gravity and thus to be categorized as dwarf planets. Astronomers generally accept about nine objects as dwarf planets: the asteroid Ceres, the Kuiper-belt objects Pluto, Orcus, Haumea, Quaoar, and Makemake, and the scattered-disc objects Gonggong, Eris, and Sedna.[d] Various small-body populations, including comets, centaurs and interplanetary dust clouds, freely travel between the regions of the Solar System. The solar wind, a stream of charged particles flowing outwards from the Sun, creates a bubble-like region of interplanetary medium in the interstellar medium known as the heliosphere. The heliopause is the point at which pressure from the solar wind is equal to the opposing pressure of the interstellar medium; it extends out to the edge of the scattered disc. The Oort cloud, which is thought to be the source for long-period comets, may also exist at a distance roughly a thousand times further than the heliosphere. The Solar System is located 26,000 light-years from the center of the Milky Way galaxy in the Orion Arm, which contains most of the visible stars in the night sky. The nearest stars are within the so-called Local Bubble, with the closest, Proxima Centauri, at 4.2441 light-years.... Inner Solar System Overview of the Inner Solar System up to the Jovian System The inner Solar System is the region comprising the terrestrial planets and the asteroid belt.[87] Composed mainly of silicates and metals,[88] the objects of the inner Solar System are relatively close to the Sun; the radius of this entire region is less than the distance between the orbits of Jupiter and Saturn. This region is also within the frost line, which is a little less than 5 AU (750 million km; 460 million mi) from the Sun.[28] Inner planets Main article: Terrestrial planet The four terrestrial planets Mercury, Venus, Earth and Mars The four terrestrial or inner planets have dense, rocky compositions, few or no moons, and no ring systems. They are composed largely of refractory minerals such as the silicates—which form their crusts and mantles—and metals such as iron and nickel which form their cores. Three of the four inner planets (Venus, Earth and Mars) have atmospheres substantial enough to generate weather; all have impact craters and tectonic surface features, such as rift valleys and volcanoes. The term inner planet should not be confused with inferior planet, which designates those planets that are closer to the Sun than Earth is (i.e. Mercury and Venus).[89] Mercury Main article: Mercury (planet) Mercury (0.307–0.588 AU (45.9–88.0 million km; 28.5–54.7 million mi) from the Sun[90]) is the closest planet to the Sun. The smallest planet in the Solar System (0.055 MEarth), Mercury has no natural satellites. The dominant geological features are impact craters or basins with ejecta blankets, the remains of early volcanic activity including magma flows, and lobed ridges or rupes that were probably produced by a period of contraction early in the planet's history.[91] Mercury's very tenuous atmosphere consists of solar-wind particles trapped by Mercury's magnetic field, as well as atoms blasted off its surface by the solar wind.[92][93] Its relatively large iron core and thin mantle have not yet been adequately explained. Hypotheses include that its outer layers were stripped off by a giant impact, or that it was prevented from fully accreting by the young Sun's energy.[94][95] There have been searches for "Vulcanoids", asteroids in stable orbits between Mercury and the Sun, but none have been discovered.[96][97] Venus Main article: Venus Venus (0.718–0.728 AU (107.4–108.9 million km; 66.7–67.7 million mi) from the Sun[90]) is close in size to Earth (0.815 MEarth) and, like Earth, has a thick silicate mantle around an iron core, a substantial atmosphere, and evidence of internal geological activity. It is much drier than Earth, and its atmosphere is ninety times as dense. Venus has no natural satellites. It is the hottest planet, with surface temperatures over 400 °C (752 °F), mainly due to the amount of greenhouse gases in the atmosphere.[98] The planet has no magnetic field that would prevent depletion of its substantial atmosphere, which suggests that its atmosphere is being replenished by volcanic eruptions.[99] A relatively young planetary surface displays extensive evidence of volcanic activity, but is devoid of plate tectonics. It may undergo resurfacing episodes on a time scale of 700 million years.[100] Earth Main article: Earth Earth (0.983–1.017 AU (147.1–152.1 million km; 91.4–94.5 million mi) from the Sun) is the largest and densest of the inner planets, the only one known to have current geological activity, and the only place where life is known to exist.[101] Its liquid hydrosphere is unique among the terrestrial planets, and it is the only planet where plate tectonics has been observed.[102] Earth's atmosphere is radically different from those of the other planets, having been altered by the presence of life to contain 21% free oxygen.[103][104] The planetary magnetosphere shields the surface from solar and cosmic radiation, limiting atmospheric stripping and maintaining habitability.[105] It has one natural satellite, the Moon, the only large satellite of a terrestrial planet in the Solar System. Mars Main article: Mars Mars (1.382–1.666 AU (206.7–249.2 million km; 128.5–154.9 million mi) from the Sun) is smaller than Earth and Venus (0.107 MEarth). It has an atmosphere of mostly carbon dioxide with a surface pressure of 6.1 millibars (0.088 psi; 0.18 inHg); roughly 0.6% of that of Earth but sufficient to support weather phenomena.[106] Its surface, peppered with volcanoes, such as Olympus Mons, and rift valleys, such as Valles Marineris, shows geological activity that may have persisted until as recently as 2 million years ago.[107] Its red color comes from iron oxide (rust) in its soil.[108] Mars has two tiny natural satellites (Deimos and Phobos) thought to be either captured asteroids,[109] or ejected debris from a massive impact early in Mars's history.[110] Asteroid belt Main articles: Asteroid belt and Asteroid Linear map of the inner Solar System, showing many asteroid populations Asteroids except for the largest, Ceres, are classified as small Solar System bodies[d] and are composed mainly of refractory rocky and metallic minerals, with some ice.[111][112] They range from a few metres to hundreds of kilometres in size. Asteroids smaller than one meter are usually called meteoroids and micrometeoroids (grain-sized), with the exact division between the two categories being debated over the years.[113] As of 2017, the IAU designates asteroids having diameter between about 30 micrometres and 1 metre as micrometeroids, and terms smaller particles "dust".[114] The asteroid belt occupies the orbit between Mars and Jupiter, between 2.3 and 3.3 AU (340 and 490 million km; 210 and 310 million mi) from the Sun. It is thought to be remnants from the Solar System's formation that failed to coalesce because of the gravitational interference of Jupiter.[115] The asteroid belt contains tens of thousands, possibly millions, of objects over one kilometre in diameter.[116] Despite this, the total mass of the asteroid belt is unlikely to be more than a thousandth of that of Earth.[46] The asteroid belt is very sparsely populated; spacecraft routinely pass through without incident.[117] Ceres Main article: Ceres (dwarf planet) Ceres (2.77 AU (414 million km; 257 million mi) from the Sun) is the largest asteroid, a protoplanet, and a dwarf planet.[d] It has a diameter of slightly under 1,000 km (620 mi) and a mass large enough for its own gravity to pull it into a spherical shape. Ceres was considered a planet when it was discovered in 1801, but as further observations revealed additional asteroids, it became common to consider it as one of the minor rather than major planets.[118] It was then reclassified again as a dwarf planet in 2006 when the IAU definition of planet was established.[119]: 218  Pallas and Vesta Main articles: 2 Pallas and 4 Vesta Pallas (2.77 AU from the Sun) and Vesta (2.36 AU from the Sun) are the largest asteroids in the asteroid belt, after Ceres. They are the other two protoplanets that survive more or less intact. At about 520 km (320 mi) in diameter, they were large enough to have developed planetary geology in the past, but both have suffered large impacts and been battered out of being round.[120][121][122] Fragments from impacts upon these two bodies survive elsewhere in the asteroid belt, as the Pallas family and Vesta family. Both were considered planets upon their discoveries in 1802 and 1807 respectively, and then like Ceres generally considered as minor planets with the discovery of more asteroids. Some authors today have begun to consider Pallas and Vesta as planets again, along with Ceres, under geophysical definitions of the term.[5] Asteroid groups Asteroids in the asteroid belt are divided into asteroid groups and families based on their orbital characteristics. Kirkwood gaps are sharp dips in the distribution of asteroid orbits that correspond to orbital resonances with Jupiter.[123] Asteroid moons are asteroids that orbit larger asteroids. They are not as clearly distinguished as planetary moons, sometimes being almost as large as their partners (e.g. that of 90 Antiope). The asteroid belt includes main-belt comets, which may have been the source of Earth's water.[124] Jupiter trojans are located in either of Jupiter's L4 or L5 points (gravitationally stable regions leading and trailing a planet in its orbit); the term trojan is also used for small bodies in any other planetary or satellite Lagrange point. Hilda asteroids are in a 2:3 resonance with Jupiter; that is, they go around the Sun three times for every two Jupiter orbits.[125] The inner Solar System contains near-Earth asteroids, many of which cross the orbits of the inner planets.[126] Some of them are potentially hazardous objects.[127] Outer Solar System Plot of objects around the Kuiper belt and other asteroid populations, the J, S, U and N denotes Jupiter, Saturn, Uranus and Neptune The outer region of the Solar System is home to the giant planets and their large moons. The centaurs and many short-period comets also orbit in this region. Due to their greater distance from the Sun, the solid objects in the outer Solar System contain a higher proportion of volatiles, such as water, ammonia, and methane than those of the inner Solar System because the lower temperatures allow these compounds to remain solid.[16] Outer planets Main article: Giant planet The outer planets Jupiter, Saturn, Uranus and Neptune, compared to the inner planets Earth, Venus, Mars, and Mercury at the bottom right The four outer planets, also called giant planets or Jovian planets, collectively make up 99% of the mass known to orbit the Sun.[f] Jupiter and Saturn are together more than 400 times the mass of Earth and consist overwhelmingly of the gases hydrogen and helium, hence their designation as gas giants.[128] Uranus and Neptune are far less massive—less than 20 Earth masses (MEarth) each—and are composed primarily of ices. For these reasons, some astronomers suggest they belong in their own category, ice giants.[129] All four giant planets have rings, although only Saturn's ring system is easily observed from Earth. The term superior planet designates planets outside Earth's orbit and thus includes both the outer planets and Mars.[89] The ring–moon systems of Jupiter, Saturn, and Uranus are like miniature versions of the Solar System; that of Neptune is significantly different, having been disrupted by the capture of its largest moon Triton.[130] Jupiter Main article: Jupiter Jupiter (4.951–5.457 AU (740.7–816.4 million km; 460.2–507.3 million mi) from the Sun[90]), at 318 MEarth, is 2.5 times the mass of all the other planets put together. It is composed largely of hydrogen and helium. Jupiter's strong internal heat creates semi-permanent features in its atmosphere, such as cloud bands and the Great Red Spot. The planet possesses a 4.2–14 Gauss strength magnetosphere that spans 22–29 million km, making it, in certain respects, the largest object in the Solar System.[131] Jupiter has 95 known satellites. The four largest, Ganymede, Callisto, Io, and Europa, are called the Galilean moons: they show similarities to the terrestrial planets, such as volcanism and internal heating.[132] Ganymede, the largest satellite in the Solar System, is larger than Mercury; Callisto is almost as large.[133] Saturn Main article: Saturn Saturn (9.075–10.07 AU (1.3576–1.5065 billion km; 843.6–936.1 million mi) from the Sun[90]), distinguished by its extensive ring system, has several similarities to Jupiter, such as its atmospheric composition and magnetosphere. Although Saturn has 60% of Jupiter's volume, it is less than a third as massive, at 95 MEarth. Saturn is the only planet of the Solar System that is less dense than water. The rings of Saturn are made up of small ice and rock particles.[134] Saturn has 83 confirmed satellites composed largely of ice. Two of these, Titan and Enceladus, show signs of geological activity;[135] they, as well as five other Saturnian moons (Iapetus, Rhea, Dione, Tethys, and Mimas), are large enough to be round. Titan, the second-largest moon in the Solar System, is bigger than Mercury and the only satellite in the Solar System to have a substantial atmosphere.[136][137] Uranus Main article: Uranus Uranus (18.27–20.06 AU (2.733–3.001 billion km; 1.698–1.865 billion mi) from the Sun[90]), at 14 MEarth, has the lowest mass of the outer planets. Uniquely among the planets, it orbits the Sun on its side; its axial tilt is over ninety degrees to the ecliptic. This gives the planet extreme seasonal variation as each pole points toward and then away from the Sun.[138] It has a much colder core than the other giant planets and radiates very little heat into space.[139] As a consequence, it has the coldest planetary atmosphere in the Solar System.[140] Uranus has 27 known satellites, the largest ones being Titania, Oberon, Umbriel, Ariel, and Miranda.[141] Like the other giant planets, it possesses a ring system and magnetosphere.[142] Neptune Main article: Neptune Neptune (29.89–30.47 AU (4.471–4.558 billion km; 2.778–2.832 billion mi) from the Sun[90]), though slightly smaller than Uranus, is more massive (17 MEarth) and hence more dense. It radiates more internal heat than Uranus, but not as much as Jupiter or Saturn.[143] Neptune has 14 known satellites. The largest, Triton, is geologically active, with geysers of liquid nitrogen.[144] Triton is the only large satellite with a retrograde orbit, which indicates that it did not form with Neptune, but was probably captured from the Kuiper belt.[145] Neptune is accompanied in its orbit by several minor planets, termed Neptune trojans, that either lead or trail the planet by about one-sixth of the way around the Sun, positions known as Lagrange points.[146] Centaurs Main article: Centaur (small Solar System body) The centaurs are icy comet-like bodies whose orbits have semi-major axes greater than Jupiter's (5.5 AU (820 million km; 510 million mi)) and less than Neptune's (30 AU (4.5 billion km; 2.8 billion mi)). These are former Kuiper belt and scattered disc objects that were gravitationally perturbed closer to the Sun by the outer planets, and are expected to become comets or get ejected out of the Solar System.[45] While most centaurs are inactive and asteroid-like, some exhibit clear cometary activity, such as the first centaur discovered, 2060 Chiron, which has been classified as a comet (95P) because it develops a coma just as comets do when they approach the Sun.[147] The largest known centaur, 10199 Chariklo, has a diameter of about 250 km (160 mi) and is one of the only few minor planets known to possess a ring system." (wikipedia.org) "Outer space, commonly shortened to space, is an infinite expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty; it is a near-perfect vacuum[1] containing a low density of particles, predominantly a plasma of hydrogen and helium, as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins (−270 °C; −455 °F).[2] The plasma between galaxies is thought to account for about half of the baryonic (ordinary) matter in the universe, having a number density of less than one hydrogen atom per cubic metre and a kinetic temperature of millions of kelvins.[3] Local concentrations of matter have condensed into stars and galaxies. Intergalactic space takes up most of the volume of the universe, but even galaxies and star systems consist almost entirely of empty space. Most of the remaining mass-energy in the observable universe is made up of an unknown form, dubbed dark matter and dark energy.[4][5][6][7] Outer space does not begin at a definite altitude above Earth's surface. The Kármán line, an altitude of 100 km (62 mi) above sea level,[8][9] is conventionally used as the start of outer space in space treaties and for aerospace records keeping. Certain portions of the upper stratosphere and the mesosphere are sometimes referred to as "near space". The framework for international space law was established by the Outer Space Treaty, which entered into force on 10 October 1967. This treaty precludes any claims of national sovereignty and permits all states to freely explore outer space. Despite the drafting of UN resolutions for the peaceful uses of outer space, anti-satellite weapons have been tested in Earth orbit. Humans began the physical exploration of space during the 20th century with the advent of high-altitude balloon flights. This was followed by crewed rocket flights and, then, crewed Earth orbit, first achieved by Yuri Gagarin of the Soviet Union in 1961. The economic cost of putting objects, including humans, into space is very high, limiting human spaceflight to low Earth orbit and the Moon. On the other hand, uncrewed spacecraft have reached all of the known planets in the Solar System. Outer space represents a challenging environment for human exploration because of the hazards of vacuum and radiation. Microgravity has a negative effect on human physiology that causes both muscle atrophy and bone loss. Formation and state Main article: Big Bang This is an artist's concept of the metric expansion of space, where a volume of the Universe is represented at each time interval by the circular sections. At left is depicted the rapid inflation from the initial state, followed thereafter by steadier expansion to the present day, shown at right. A black background with luminous shapes of various sizes scattered randomly about. They typically have white, red or blue hues. Part of the Hubble Ultra-Deep Field image showing a typical section of space containing galaxies interspersed by deep vacuum. Given the finite speed of light, this view covers the past 13 billion years of the history of outer space. The size of the whole universe is unknown, and it might be infinite in extent.[10] According to the Big Bang theory, the very early Universe was an extremely hot and dense state about 13.8 billion years ago[11] which rapidly expanded. About 380,000 years later the Universe had cooled sufficiently to allow protons and electrons to combine and form hydrogen—the so-called recombination epoch. When this happened, matter and energy became decoupled, allowing photons to travel freely through the continually expanding space.[12] Matter that remained following the initial expansion has since undergone gravitational collapse to create stars, galaxies and other astronomical objects, leaving behind a deep vacuum that forms what is now called outer space.[13] As light has a finite velocity, this theory also constrains the size of the directly observable universe.[12] The present day shape of the universe has been determined from measurements of the cosmic microwave background using satellites like the Wilkinson Microwave Anisotropy Probe. These observations indicate that the spatial geometry of the observable universe is "flat", meaning that photons on parallel paths at one point remain parallel as they travel through space to the limit of the observable universe, except for local gravity.[14] The flat Universe, combined with the measured mass density of the Universe and the accelerating expansion of the Universe, indicates that space has a non-zero vacuum energy, which is called dark energy.[15] Estimates put the average energy density of the present day Universe at the equivalent of 5.9 protons per cubic meter, including dark energy, dark matter, and baryonic matter (ordinary matter composed of atoms). The atoms account for only 4.6% of the total energy density, or a density of one proton per four cubic meters.[16] The density of the Universe is clearly not uniform; it ranges from relatively high density in galaxies—including very high density in structures within galaxies, such as planets, stars, and black holes—to conditions in vast voids that have much lower density, at least in terms of visible matter.[17] Unlike matter and dark matter, dark energy seems not to be concentrated in galaxies: although dark energy may account for a majority of the mass-energy in the Universe, dark energy's influence is 5 orders of magnitude smaller than the influence of gravity from matter and dark matter within the Milky Way.[18] Environment The interplanetary dust cloud illuminated and visible as zodiacal light, with its parts the false dawn,[19] gegenschein and the rest of its band, which is visually crossed by the Milky Way Outer space is the closest known approximation to a perfect vacuum. It has effectively no friction, allowing stars, planets, and moons to move freely along their ideal orbits, following the initial formation stage. The deep vacuum of intergalactic space is not devoid of matter, as it contains a few hydrogen atoms per cubic meter.[20] By comparison, the air humans breathe contains about 1025 molecules per cubic meter.[21][22] The low density of matter in outer space means that electromagnetic radiation can travel great distances without being scattered: the mean free path of a photon in intergalactic space is about 1023 km, or 10 billion light years.[23] In spite of this, extinction, which is the absorption and scattering of photons by dust and gas, is an important factor in galactic and intergalactic astronomy.[24] Stars, planets, and moons retain their atmospheres by gravitational attraction. Atmospheres have no clearly delineated upper boundary: the density of atmospheric gas gradually decreases with distance from the object until it becomes indistinguishable from outer space.[25] The Earth's atmospheric pressure drops to about 0.032 Pa at 100 kilometres (62 miles) of altitude,[26] compared to 100,000 Pa for the International Union of Pure and Applied Chemistry (IUPAC) definition of standard pressure. Above this altitude, isotropic gas pressure rapidly becomes insignificant when compared to radiation pressure from the Sun and the dynamic pressure of the solar wind. The thermosphere in this range has large gradients of pressure, temperature and composition, and varies greatly due to space weather.[27] The temperature of outer space is measured in terms of the kinetic activity of the gas,[28] as it is on Earth. The radiation of outer space has a different temperature than the kinetic temperature of the gas, meaning that the gas and radiation are not in thermodynamic equilibrium.[29][30] All of the observable universe is filled with photons that were created during the Big Bang, which is known as the cosmic microwave background radiation (CMB). (There is quite likely a correspondingly large number of neutrinos called the cosmic neutrino background.[31]) The current black body temperature of the background radiation is about 3 K (−270 °C; −454 °F).[32] The gas temperatures in outer space can vary widely. For example, the temperature in the Boomerang Nebula is 1 K,[33] while the solar corona reaches temperatures over 1.2–2.6 million K.[34] Magnetic fields have been detected in the space around just about every class of celestial object. Star formation in spiral galaxies can generate small-scale dynamos, creating turbulent magnetic field strengths of around 5–10 μG. The Davis–Greenstein effect causes elongated dust grains to align themselves with a galaxy's magnetic field, resulting in weak optical polarization. This has been used to show ordered magnetic fields exist in several nearby galaxies. Magneto-hydrodynamic processes in active elliptical galaxies produce their characteristic jets and radio lobes. Non-thermal radio sources have been detected even among the most distant, high-z sources, indicating the presence of magnetic fields.[35] Outside a protective atmosphere and magnetic field, there are few obstacles to the passage through space of energetic subatomic particles known as cosmic rays. These particles have energies ranging from about 106 eV up to an extreme 1020 eV of ultra-high-energy cosmic rays.[36] The peak flux of cosmic rays occurs at energies of about 109 eV, with approximately 87% protons, 12% helium nuclei and 1% heavier nuclei. In the high energy range, the flux of electrons is only about 1% of that of protons.[37] Cosmic rays can damage electronic components and pose a health threat to space travelers.[38] According to astronauts, like Don Pettit, space has a burned/metallic odor that clings to their suits and equipment, similar to the scent of an arc welding torch.[39][40] Effect on biology and human bodies Main articles: Effect of spaceflight on the human body, Bioastronautics, Uncontrolled decompression, and Weightlessness See also: Astrobiology, Astrobotany, Plants in space, and Animals in space The lower half shows a blue planet with patchy white clouds. The upper half has a man in a white spacesuit and maneuvering unit against a black background. Because of the hazards of a vacuum, astronauts must wear a pressurized space suit while off-Earth and outside their spacecraft. Despite the harsh environment, several life forms have been found that can withstand extreme space conditions for extended periods. Species of lichen carried on the ESA BIOPAN facility survived exposure for ten days in 2007.[41] Seeds of Arabidopsis thaliana and Nicotiana tabacum germinated after being exposed to space for 1.5 years.[42] A strain of Bacillus subtilis has survived 559 days when exposed to low Earth orbit or a simulated martian environment.[43] The lithopanspermia hypothesis suggests that rocks ejected into outer space from life-harboring planets may successfully transport life forms to another habitable world. A conjecture is that just such a scenario occurred early in the history of the Solar System, with potentially microorganism-bearing rocks being exchanged between Venus, Earth, and Mars.[44] Even at relatively low altitudes in the Earth's atmosphere, conditions are hostile to the human body. The altitude where atmospheric pressure matches the vapor pressure of water at the temperature of the human body is called the Armstrong line, named after American physician Harry G. Armstrong. It is located at an altitude of around 19.14 km (11.89 mi). At or above the Armstrong line, fluids in the throat and lungs boil away. More specifically, exposed bodily liquids such as saliva, tears, and liquids in the lungs boil away. Hence, at this altitude, human survival requires a pressure suit, or a pressurized capsule.[45] Out in space, sudden exposure of an unprotected human to very low pressure, such as during a rapid decompression, can cause pulmonary barotrauma—a rupture of the lungs, due to the large pressure differential between inside and outside the chest.[46] Even if the subject's airway is fully open, the flow of air through the windpipe may be too slow to prevent the rupture.[47] Rapid decompression can rupture eardrums and sinuses, bruising and blood seep can occur in soft tissues, and shock can cause an increase in oxygen consumption that leads to hypoxia.[48] As a consequence of rapid decompression, oxygen dissolved in the blood empties into the lungs to try to equalize the partial pressure gradient. Once the deoxygenated blood arrives at the brain, humans lose consciousness after a few seconds and die of hypoxia within minutes.[49] Blood and other body fluids boil when the pressure drops below 6.3 kPa, and this condition is called ebullism.[50] The steam may bloat the body to twice its normal size and slow circulation, but tissues are elastic and porous enough to prevent rupture. Ebullism is slowed by the pressure containment of blood vessels, so some blood remains liquid.[51][52] Swelling and ebullism can be reduced by containment in a pressure suit. The Crew Altitude Protection Suit (CAPS), a fitted elastic garment designed in the 1960s for astronauts, prevents ebullism at pressures as low as 2 kPa.[53] Supplemental oxygen is needed at 8 km (5 mi) to provide enough oxygen for breathing and to prevent water loss, while above 20 km (12 mi) pressure suits are essential to prevent ebullism.[54] Most space suits use around 30–39 kPa of pure oxygen, about the same as on the Earth's surface. This pressure is high enough to prevent ebullism, but evaporation of nitrogen dissolved in the blood could still cause decompression sickness and gas embolisms if not managed.[55] Humans evolved for life in Earth gravity, and exposure to weightlessness has been shown to have deleterious effects on human health. Initially, more than 50% of astronauts experience space motion sickness. This can cause nausea and vomiting, vertigo, headaches, lethargy, and overall malaise. The duration of space sickness varies, but it typically lasts for 1–3 days, after which the body adjusts to the new environment. Longer-term exposure to weightlessness results in muscle atrophy and deterioration of the skeleton, or spaceflight osteopenia. These effects can be minimized through a regimen of exercise.[56] Other effects include fluid redistribution, slowing of the cardiovascular system, decreased production of red blood cells, balance disorders, and a weakening of the immune system. Lesser symptoms include loss of body mass, nasal congestion, sleep disturbance, and puffiness of the face.[57] During long-duration space travel, radiation can pose an acute health hazard. Exposure to high-energy, ionizing cosmic rays can result in fatigue, nausea, vomiting, as well as damage to the immune system and changes to the white blood cell count. Over longer durations, symptoms include an increased risk of cancer, plus damage to the eyes, nervous system, lungs and the gastrointestinal tract.[58] On a round-trip Mars mission lasting three years, a large fraction of the cells in an astronaut's body would be traversed and potentially damaged by high energy nuclei.[59] The energy of such particles is significantly diminished by the shielding provided by the walls of a spacecraft and can be further diminished by water containers and other barriers. The impact of the cosmic rays upon the shielding produces additional radiation that can affect the crew. Further research is needed to assess the radiation hazards and determine suitable countermeasures.... Interplanetary space Main article: Interplanetary medium At lower left, a white coma stands out against a black background. Nebulous material streams away to the top and left, slowly fading with distance. The sparse plasma (blue) and dust (white) in the tail of comet Hale–Bopp are being shaped by pressure from solar radiation and the solar wind, respectively. Interplanetary space is defined by the solar wind, a continuous stream of charged particles emanating from the Sun that creates a very tenuous atmosphere (the heliosphere) for billions of kilometers into space. This wind has a particle density of 5–10 protons/cm3 and is moving at a velocity of 350–400 km/s (780,000–890,000 mph).[105] Interplanetary space extends out to the heliopause where the influence of the galactic environment starts to dominate over the magnetic field and particle flux from the Sun.[83] The distance and strength of the heliopause varies depending on the activity level of the solar wind.[106] The heliopause in turn deflects away low-energy galactic cosmic rays, with this modulation effect peaking during solar maximum.[107] The volume of interplanetary space is a nearly total vacuum, with a mean free path of about one astronomical unit at the orbital distance of the Earth. This space is not completely empty, and is sparsely filled with cosmic rays, which include ionized atomic nuclei and various subatomic particles. There is also gas, plasma and dust,[108] small meteors, and several dozen types of organic molecules discovered to date by microwave spectroscopy.[109] A cloud of interplanetary dust is visible at night as a faint band called the zodiacal light.[110] Interplanetary space contains the magnetic field generated by the Sun.[105] There are also magnetospheres generated by planets such as Jupiter, Saturn, Mercury and the Earth that have their own magnetic fields. These are shaped by the influence of the solar wind into the approximation of a teardrop shape, with the long tail extending outward behind the planet. These magnetic fields can trap particles from the solar wind and other sources, creating belts of charged particles such as the Van Allen radiation belts. Planets without magnetic fields, such as Mars, have their atmospheres gradually eroded by the solar wind.[111] Interstellar space Main article: Interstellar medium "Interstellar space" redirects here. For the album, see Interstellar Space. Patchy orange and blue nebulosity against a black background, with a curved orange arc wrapping around a star at the center. Bow shock formed by the magnetosphere of the young star LL Orionis (center) as it collides with the Orion Nebula flow Interstellar space is the physical space within a galaxy beyond the influence each star has upon the encompassed plasma.[84] The contents of interstellar space are called the interstellar medium. Approximately 70% of the mass of the interstellar medium consists of lone hydrogen atoms; most of the remainder consists of helium atoms. This is enriched with trace amounts of heavier atoms formed through stellar nucleosynthesis. These atoms are ejected into the interstellar medium by stellar winds or when evolved stars begin to shed their outer envelopes such as during the formation of a planetary nebula.[112] The cataclysmic explosion of a supernova generates an expanding shock wave consisting of ejected materials that further enrich the medium.[113] The density of matter in the interstellar medium can vary considerably: the average is around 106 particles per m3,[114] but cold molecular clouds can hold 108–1012 per m3.[29][112] A number of molecules exist in interstellar space, as can tiny 0.1 μm dust particles.[115] The tally of molecules discovered through radio astronomy is steadily increasing at the rate of about four new species per year. Large regions of higher density matter known as molecular clouds allow chemical reactions to occur, including the formation of organic polyatomic species. Much of this chemistry is driven by collisions. Energetic cosmic rays penetrate the cold, dense clouds and ionize hydrogen and helium, resulting, for example, in the trihydrogen cation. An ionized helium atom can then split relatively abundant carbon monoxide to produce ionized carbon, which in turn can lead to organic chemical reactions.[116] The local interstellar medium is a region of space within 100 parsecs (pc) of the Sun, which is of interest both for its proximity and for its interaction with the Solar System. This volume nearly coincides with a region of space known as the Local Bubble, which is characterized by a lack of dense, cold clouds. It forms a cavity in the Orion Arm of the Milky Way galaxy, with dense molecular clouds lying along the borders, such as those in the constellations of Ophiuchus and Taurus. (The actual distance to the border of this cavity varies from 60 to 250 pc or more.) This volume contains about 104–105 stars and the local interstellar gas counterbalances the astrospheres that surround these stars, with the volume of each sphere varying depending on the local density of the interstellar medium. The Local Bubble contains dozens of warm interstellar clouds with temperatures of up to 7,000 K and radii of 0.5–5 pc.[117] When stars are moving at sufficiently high peculiar velocities, their astrospheres can generate bow shocks as they collide with the interstellar medium. For decades it was assumed that the Sun had a bow shock. In 2012, data from Interstellar Boundary Explorer (IBEX) and NASA's Voyager probes showed that the Sun's bow shock does not exist. Instead, these authors argue that a subsonic bow wave defines the transition from the solar wind flow to the interstellar medium.[118][119] A bow shock is the third boundary of an astrosphere after the termination shock and the astropause (called the heliopause in the Solar System).[119] Intergalactic space Structure of the Universe Large-scale matter distribution in a cubic section of the universe. The blue fiber structures represent the matter and the empty regions in between represent the cosmic voids of the intergalactic medium. Main articles: Warm–hot intergalactic medium, Intracluster medium, and Intergalactic dust Intergalactic space is the physical space between galaxies. Studies of the large-scale distribution of galaxies show that the Universe has a foam-like structure, with groups and clusters of galaxies lying along filaments that occupy about a tenth of the total space. The remainder forms huge voids that are mostly empty of galaxies. Typically, a void spans a distance of 7–30 megaparsecs.[120] Surrounding and stretching between galaxies, there is a rarefied plasma[121] that is organized in a galactic filamentary structure.[122] This material is called the intergalactic medium (IGM). The density of the IGM is 5–200 times the average density of the Universe.[123] It consists mostly of ionized hydrogen; i.e. a plasma consisting of equal numbers of electrons and protons. As gas falls into the intergalactic medium from the voids, it heats up to temperatures of 105 K to 107 K,[3] which is high enough so that collisions between atoms have enough energy to cause the bound electrons to escape from the hydrogen nuclei; this is why the IGM is ionized. At these temperatures, it is called the warm–hot intergalactic medium (WHIM). (Although the plasma is very hot by terrestrial standards, 105 K is often called "warm" in astrophysics.) Computer simulations and observations indicate that up to half of the atomic matter in the Universe might exist in this warm–hot, rarefied state.[123][124][125] When gas falls from the filamentary structures of the WHIM into the galaxy clusters at the intersections of the cosmic filaments, it can heat up even more, reaching temperatures of 108 K and above in the so-called intracluster medium (ICM)." (wikipedia.org) "The International Space Station (ISS) is the largest modular space station in low Earth orbit. The project involves five space agencies: the United States' NASA, Russia's Roscosmos, Japan's JAXA, Europe's ESA, and Canada's CSA.[9][10] The ownership and use of the space station is established by intergovernmental treaties and agreements.[11] The station serves as a microgravity and space environment research laboratory in which scientific research is conducted in astrobiology, astronomy, meteorology, physics, and other fields.[12][13] The ISS is suited for testing the spacecraft systems and equipment required for possible future long-duration missions to the Moon and Mars.[14] The ISS programme evolved from the Space Station Freedom, a 1984 American proposal to construct a permanently crewed Earth-orbiting station,[15] and the contemporaneous Soviet/Russian Mir-2 proposal from 1976 with similar aims. The ISS is the ninth space station to be inhabited by crews, following the Soviet and later Russian Salyut, Almaz, and Mir stations and the American Skylab. It is the largest artificial object in the solar system and the largest satellite in low Earth orbit, regularly visible to the naked eye from Earth's surface.[16][17] It maintains an orbit with an average altitude of 400 kilometres (250 mi) by means of reboost manoeuvres using the engines of the Zvezda Service Module or visiting spacecraft.[18] The ISS circles the Earth in roughly 93 minutes, completing 15.5 orbits per day.[19] The station is divided into two sections: the Russian Orbital Segment (ROS) is operated by Russia, while the United States Orbital Segment (USOS) is run by the United States as well as by the other states. The Russian segment includes six modules. The US segment includes ten modules, whose support services are distributed 76.6% for NASA, 12.8% for JAXA, 8.3% for ESA and 2.3% for CSA. The length along the major axis of the pressurized sections is 218 ft (66 m), and the total habitable volume of these sections is 13,696 cu ft (387.8 m3).[2] Roscosmos had previously[20][21] endorsed the continued operation of ROS through 2024,[22] having proposed using elements of the segment to construct a new Russian space station called OPSEK.[23] However, continued cooperation has been rendered uncertain by the 2022 Russian invasion of Ukraine and subsequent international sanctions on Russia, which may cause changes in funding on their side of the space station.[20][21] The first ISS component was launched in 1998, and the first long-term residents arrived on 2 November 2000 after being launched from the Baikonur Cosmodrome on 31 October 2000.[24] The station has since been continuously occupied for 22 years and 174 days,[25] the longest continuous human presence in low Earth orbit, having surpassed the previous record of 9 years and 357 days held by the Mir space station. The latest major pressurised module, Nauka, was fitted in 2021, a little over ten years after the previous major addition, Leonardo in 2011. In January 2022, the station's operation authorization was extended to 2030, with funding secured within the United States through that year.[26][27] There have been calls to privatize ISS operations after that point to pursue future Moon and Mars missions, with former NASA Administrator Jim Bridenstine stating: "given our current budget constraints, if we want to go to the moon and we want to go to Mars, we need to commercialize low Earth orbit and go on to the next step."[28] The ISS consists of pressurised habitation modules, structural trusses, photovoltaic solar arrays, thermal radiators, docking ports, experiment bays and robotic arms. Major ISS modules have been launched by Russian Proton and Soyuz rockets and US Space Shuttles.[29] The station is serviced by a variety of visiting spacecraft: the Russian Soyuz and Progress, the SpaceX Dragon 2, and the Northrop Grumman Space Systems Cygnus,[30] and formerly the European Automated Transfer Vehicle (ATV), the Japanese H-II Transfer Vehicle,[9] and SpaceX Dragon 1. The Dragon spacecraft allows the return of pressurised cargo to Earth, which is used, for example, to repatriate scientific experiments for further analysis. As of April 2022, 251 astronauts, cosmonauts, and space tourists from 20 different nations have visited the space station, many of them multiple times. History This section is an excerpt from International Space Station programme § History and conception.[edit] In the early 1980s, NASA planned to launch a modular space station called Freedom as a counterpart to the Soviet Salyut and Mir space stations. In 1984 the ESA was invited to participate in Space Station Freedom, and the ESA approved the Columbus laboratory by 1987.[31] The Japanese Experiment Module (JEM), or Kibō, was announced in 1985, as part of the Freedom space station in response to a NASA request in 1982. In early 1985, science ministers from the European Space Agency (ESA) countries approved the Columbus programme, the most ambitious effort in space undertaken by that organisation at the time. The plan spearheaded by Germany and Italy included a module which would be attached to Freedom, and with the capability to evolve into a full-fledged European orbital outpost before the end of the century. The space station was also going to tie the emerging European and Japanese national space programmes closer to the US-led project, thereby preventing those nations from becoming major, independent competitors too.[32] In September 1993, American Vice-President Al Gore and Russian Prime Minister Viktor Chernomyrdin announced plans for a new space station, which eventually became the International Space Station.[33] They also agreed, in preparation for this new project, that the United States would be involved in the Mir programme, including American Shuttles docking, in the Shuttle–Mir programme.[34] On 12 April 2021, at a meeting with Russian President Vladimir Putin, then-Deputy Prime Minister Yury Borisov announced he had decided that Russia might withdraw from the ISS programme in 2025.[35][36] According to Russian authorities, the timeframe of the station's operations has expired and its condition leaves much to be desired.[35] On 26 July 2022, Borisov, who had become head of Roscosmos, submitted to Putin his plans for withdrawal from the programme after 2024.[37] However, Robyn Gatens, the NASA official in charge of space station operations, responded that NASA had not received any formal notices from Roscosmos concerning withdrawal plans.[38] On 21 September 2022, Borisov stated that Russia was "highly likely" to continue to participate in the ISS programme until 2028.[39] Purpose The ISS was originally intended to be a laboratory, observatory, and factory while providing transportation, maintenance, and a low Earth orbit staging base for possible future missions to the Moon, Mars, and asteroids. However, not all of the uses envisioned in the initial memorandum of understanding between NASA and Roscosmos have been realised.[40] In the 2010 United States National Space Policy, the ISS was given additional roles of serving commercial, diplomatic,[41] and educational purposes.[42] Scientific research Main article: Scientific research on the International Space Station Comet Lovejoy photographed by Expedition 30 commander Dan Burbank Expedition 8 Commander and Science Officer Michael Foale conducts an inspection of the Microgravity Science Glovebox. Fisheye view of several labs and the Space Shuttle CubeSats are deployed by the NanoRacks CubeSat Deployer. The ISS provides a platform to conduct scientific research, with power, data, cooling, and crew available to support experiments. Small uncrewed spacecraft can also provide platforms for experiments, especially those involving zero gravity and exposure to space, but space stations offer a long-term environment where studies can be performed potentially for decades, combined with ready access by human researchers.[43][44] The ISS simplifies individual experiments by allowing groups of experiments to share the same launches and crew time. Research is conducted in a wide variety of fields, including astrobiology, astronomy, physical sciences, materials science, space weather, meteorology, and human research including space medicine and the life sciences.[12][13][45][46] Scientists on Earth have timely access to the data and can suggest experimental modifications to the crew. If follow-on experiments are necessary, the routinely scheduled launches of resupply craft allows new hardware to be launched with relative ease.[44] Crews fly expeditions of several months' duration, providing approximately 160 person-hours per week of labour with a crew of six. However, a considerable amount of crew time is taken up by station maintenance.[47] Perhaps the most notable ISS experiment is the Alpha Magnetic Spectrometer (AMS), which is intended to detect dark matter and answer other fundamental questions about our universe. According to NASA, the AMS is as important as the Hubble Space Telescope. Currently docked on station, it could not have been easily accommodated on a free flying satellite platform because of its power and bandwidth needs.[48][49] On 3 April 2013, scientists reported that hints of dark matter may have been detected by the AMS.[50][51][52][53][54][55] According to the scientists, "The first results from the space-borne Alpha Magnetic Spectrometer confirm an unexplained excess of high-energy positrons in Earth-bound cosmic rays". The space environment is hostile to life. Unprotected presence in space is characterised by an intense radiation field (consisting primarily of protons and other subatomic charged particles from the solar wind, in addition to cosmic rays), high vacuum, extreme temperatures, and microgravity.[56] Some simple forms of life called extremophiles,[57] as well as small invertebrates called tardigrades[58] can survive in this environment in an extremely dry state through desiccation. Medical research improves knowledge about the effects of long-term space exposure on the human body, including muscle atrophy, bone loss, and fluid shift. These data will be used to determine whether high duration human spaceflight and space colonisation are feasible. In 2006, data on bone loss and muscular atrophy suggested that there would be a significant risk of fractures and movement problems if astronauts landed on a planet after a lengthy interplanetary cruise, such as the six-month interval required to travel to Mars.[59][60] Medical studies are conducted aboard the ISS on behalf of the National Space Biomedical Research Institute (NSBRI). Prominent among these is the Advanced Diagnostic Ultrasound in Microgravity study in which astronauts perform ultrasound scans under the guidance of remote experts. The study considers the diagnosis and treatment of medical conditions in space. Usually, there is no physician on board the ISS and diagnosis of medical conditions is a challenge. It is anticipated that remotely guided ultrasound scans will have application on Earth in emergency and rural care situations where access to a trained physician is difficult.[61][62][63] In August 2020, scientists reported that bacteria from Earth, particularly Deinococcus radiodurans bacteria, which is highly resistant to environmental hazards, were found to survive for three years in outer space, based on studies conducted on the International Space Station. These findings supported the notion of panspermia, the hypothesis that life exists throughout the Universe, distributed in various ways, including space dust, meteoroids, asteroids, comets, planetoids or contaminated spacecraft.[64][65] Remote sensing of the Earth, astronomy, and deep space research on the ISS have dramatically increased during the 2010s after the completion of the US Orbital Segment in 2011. Throughout the more than 20 years of the ISS program researchers aboard the ISS and on the ground have examined aerosols, ozone, lightning, and oxides in Earth's atmosphere, as well as the Sun, cosmic rays, cosmic dust, antimatter, and dark matter in the universe. Examples of Earth-viewing remote sensing experiments that have flown on the ISS are the Orbiting Carbon Observatory 3, ISS-RapidScat, ECOSTRESS, the Global Ecosystem Dynamics Investigation, and the Cloud Aerosol Transport System. ISS-based astronomy telescopes and experiments include SOLAR, the Neutron Star Interior Composition Explorer, the Calorimetric Electron Telescope, the Monitor of All-sky X-ray Image (MAXI), and the Alpha Magnetic Spectrometer.[12][66] Freefall ISS crew member storing samples A comparison between the combustion of a candle on Earth (left) and in a free fall environment, such as that found on the ISS (right) Gravity at the altitude of the ISS is approximately 90% as strong as at Earth's surface, but objects in orbit are in a continuous state of freefall, resulting in an apparent state of weightlessness.[67] This perceived weightlessness is disturbed by five effects:[68]     Drag from the residual atmosphere.     Vibration from the movements of mechanical systems and the crew.     Actuation of the on-board attitude control moment gyroscopes.     Thruster firings for attitude or orbital changes.     Gravity-gradient effects, also known as tidal effects. Items at different locations within the ISS would, if not attached to the station, follow slightly different orbits. Being mechanically connected these items experience small forces that keep the station moving as a rigid body. Researchers are investigating the effect of the station's near-weightless environment on the evolution, development, growth and internal processes of plants and animals. In response to some of the data, NASA wants to investigate microgravity's effects on the growth of three-dimensional, human-like tissues and the unusual protein crystals that can be formed in space.[12] Investigating the physics of fluids in microgravity will provide better models of the behaviour of fluids. Because fluids can be almost completely combined in microgravity, physicists investigate fluids that do not mix well on Earth. Examining reactions that are slowed by low gravity and low temperatures will improve our understanding of superconductivity.[12] The study of materials science is an important ISS research activity, with the objective of reaping economic benefits through the improvement of techniques used on the ground.[69] Other areas of interest include the effect of low gravity on combustion, through the study of the efficiency of burning and control of emissions and pollutants. These findings may improve knowledge about energy production and lead to economic and environmental benefits.[12] Exploration A 3D plan of the Russia-based MARS-500 complex, used for conducting ground-based experiments that complement ISS-based preparations for a human mission to Mars The ISS provides a location in the relative safety of low Earth orbit to test spacecraft systems that will be required for long-duration missions to the Moon and Mars. This provides experience in operations, maintenance as well as repair and replacement activities on-orbit. This will help develop essential skills in operating spacecraft farther from Earth, reduce mission risks, and advance the capabilities of interplanetary spacecraft.[14] Referring to the MARS-500 experiment, a crew isolation experiment conducted on Earth, ESA states that "Whereas the ISS is essential for answering questions concerning the possible impact of weightlessness, radiation and other space-specific factors, aspects such as the effect of long-term isolation and confinement can be more appropriately addressed via ground-based simulations".[70] Sergey Krasnov, the head of human space flight programmes for Russia's space agency, Roscosmos, in 2011 suggested a "shorter version" of MARS-500 may be carried out on the ISS.[71] In 2009, noting the value of the partnership framework itself, Sergey Krasnov wrote, "When compared with partners acting separately, partners developing complementary abilities and resources could give us much more assurance of the success and safety of space exploration. The ISS is helping further advance near-Earth space exploration and realisation of prospective programmes of research and exploration of the Solar system, including the Moon and Mars."[72] A crewed mission to Mars may be a multinational effort involving space agencies and countries outside the current ISS partnership. In 2010, ESA Director-General Jean-Jacques Dordain stated his agency was ready to propose to the other four partners that China, India and South Korea be invited to join the ISS partnership.[73] NASA chief Charles Bolden stated in February 2011, "Any mission to Mars is likely to be a global effort".[74] Currently, US federal legislation prevents NASA co-operation with China on space projects.[75] Education and cultural outreach Original Jules Verne manuscripts displayed by crew inside the Jules Verne ATV The ISS crew provides opportunities for students on Earth by running student-developed experiments, making educational demonstrations, allowing for student participation in classroom versions of ISS experiments, and directly engaging students using radio, and email.[9][76] ESA offers a wide range of free teaching materials that can be downloaded for use in classrooms.[77] In one lesson, students can navigate a 3D model of the interior and exterior of the ISS, and face spontaneous challenges to solve in real time.[78] The Japanese Aerospace Exploration Agency (JAXA) aims to inspire children to "pursue craftsmanship" and to heighten their "awareness of the importance of life and their responsibilities in society".[79] Through a series of education guides, students develop a deeper understanding of the past and near-term future of crewed space flight, as well as that of Earth and life.[80][81] In the JAXA "Seeds in Space" experiments, the mutation effects of spaceflight on plant seeds aboard the ISS are explored by growing sunflower seeds that have flown on the ISS for about nine months. In the first phase of Kibō utilisation from 2008 to mid-2010, researchers from more than a dozen Japanese universities conducted experiments in diverse fields.[82] Cultural activities are another major objective of the ISS programme. Tetsuo Tanaka, the director of JAXA's Space Environment and Utilization Center, has said: "There is something about space that touches even people who are not interested in science."[83] Amateur Radio on the ISS (ARISS) is a volunteer programme that encourages students worldwide to pursue careers in science, technology, engineering, and mathematics, through amateur radio communications opportunities with the ISS crew. ARISS is an international working group, consisting of delegations from nine countries including several in Europe, as well as Japan, Russia, Canada, and the United States. In areas where radio equipment cannot be used, speakerphones connect students to ground stations which then connect the calls to the space station.[84] 0:45 Spoken voice recording by ESA astronaut Paolo Nespoli on the subject of the ISS, produced in November 2017 for Wikipedia First Orbit is a 2011 feature-length documentary film about Vostok 1, the first crewed space flight around the Earth. By matching the orbit of the ISS to that of Vostok 1 as closely as possible, in terms of ground path and time of day, documentary filmmaker Christopher Riley and ESA astronaut Paolo Nespoli were able to film the view that Yuri Gagarin saw on his pioneering orbital space flight. This new footage was cut together with the original Vostok 1 mission audio recordings sourced from the Russian State Archive. Nespoli is credited as the director of photography for this documentary film, as he recorded the majority of the footage himself during Expedition 26/27.[85] The film was streamed in a global YouTube premiere in 2011 under a free licence through the website firstorbit.org.[86] In May 2013, commander Chris Hadfield shot a music video of David Bowie's "Space Oddity" on board the station, which was released on YouTube.[87][88] It was the first music video ever to be filmed in space.[89] In November 2017, while participating in Expedition 52/53 on the ISS, Paolo Nespoli made two recordings of his spoken voice (one in English and the other in his native Italian), for use on Wikipedia articles. These were the first content made in space specifically for Wikipedia.[90][91] In November 2021, a virtual reality exhibit called The Infinite featuring life aboard the ISS was announced.[92] Construction Manufacturing Main article: Manufacturing of the International Space Station ISS module Node 2 manufacturing and processing in the Space Station Processing Facility An MPLM module in the SSPF at Cape Canaveral Since the International Space Station is a multi-national collaborative project, the components for in-orbit assembly were manufactured in various countries around the world. Beginning in the mid-1990s, the U.S. components Destiny, Unity, the Integrated Truss Structure, and the solar arrays were fabricated at the Marshall Space Flight Center and the Michoud Assembly Facility. These modules were delivered to the Operations and Checkout Building and the Space Station Processing Facility (SSPF) for final assembly and processing for launch.[93] The Russian modules, including Zarya and Zvezda, were manufactured at the Khrunichev State Research and Production Space Center in Moscow. Zvezda was initially manufactured in 1985 as a component for Mir-2, but was never launched and instead became the ISS Service Module.[94] The European Space Agency (ESA) Columbus module was manufactured at the EADS Astrium Space Transportation facilities in Bremen, Germany, along with many other contractors throughout Europe.[95] The other ESA-built modules – Harmony, Tranquility, the Leonardo MPLM, and the Cupola – were initially manufactured at the Thales Alenia Space factory in Turin, Italy.[96] The structural steel hulls of the modules were transported by aircraft to the Kennedy Space Center SSPF for launch processing.[97] The Japanese Experiment Module Kibō, was fabricated in various technology manufacturing facilities in Japan, at the NASDA (now JAXA) Tsukuba Space Center, and the Institute of Space and Astronautical Science. The Kibo module was transported by ship and flown by aircraft to the SSPF.[98] The Mobile Servicing System, consisting of the Canadarm2 and the Dextre grapple fixture, was manufactured at various factories in Canada (such as the David Florida Laboratory) and the United States, under contract by the Canadian Space Agency. The mobile base system, a connecting framework for Canadarm2 mounted on rails, was built by Northrop Grumman. Assembly Main articles: Assembly of the International Space Station and List of ISS spacewalks Animation of the assembly of the International Space Station The ISS was slowly assembled over more than a decade of spaceflights and crews. A view of the completed station as seen from Shuttle Atlantis during STS-132, 23 May 2010 The assembly of the International Space Station, a major endeavour in space architecture, began in November 1998.[6] Russian modules launched and docked robotically, with the exception of Rassvet. All other modules were delivered by the Space Shuttle, which required installation by ISS and Shuttle crewmembers using the Canadarm2 (SSRMS) and extra-vehicular activities (EVAs); by 5 June 2011, they had added 159 components during more than 1,000 hours of EVA. 127 of these spacewalks originated from the station, and the remaining 32 were launched from the airlocks of docked Space Shuttles.[99] The beta angle of the station had to be considered at all times during construction.[100] The first module of the ISS, Zarya, was launched on 20 November 1998 on an autonomous Russian Proton rocket. It provided propulsion, attitude control, communications, and electrical power, but lacked long-term life support functions. A passive NASA module, Unity, was launched two weeks later aboard Space Shuttle flight STS-88 and attached to Zarya by astronauts during EVAs. The Unity module has two Pressurised Mating Adapters (PMAs): one connects permanently to Zarya and the other allowed the Space Shuttle to dock to the space station. At that time, the Russian (Soviet) station Mir was still inhabited, and the ISS remained uncrewed for two years. On 12 July 2000, the Zvezda module was launched into orbit. Onboard preprogrammed commands deployed its solar arrays and communications antenna. Zvezda then became the passive target for a rendezvous with Zarya and Unity, maintaining a station-keeping orbit while the Zarya–Unity vehicle performed the rendezvous and docking via ground control and the Russian automated rendezvous and docking system. Zarya's computer transferred control of the station to Zvezda's computer soon after docking. Zvezda added sleeping quarters, a toilet, kitchen, CO2 scrubbers, dehumidifier, oxygen generators, and exercise equipment, plus data, voice and television communications with mission control, enabling permanent habitation of the station.[101][102] The first resident crew, Expedition 1, arrived in November 2000 on Soyuz TM-31. At the end of the first day on the station, astronaut Bill Shepherd requested the use of the radio call sign "Alpha", which he and cosmonaut Sergei Krikalev preferred to the more cumbersome "International Space Station".[103] The name "Alpha" had previously been used for the station in the early 1990s,[104] and its use was authorised for the whole of Expedition 1.[105] Shepherd had been advocating the use of a new name to project managers for some time. Referencing a naval tradition in a pre-launch news conference he had said: "For thousands of years, humans have been going to sea in ships. People have designed and built these vessels, launched them with a good feeling that a name will bring good fortune to the crew and success to their voyage."[106] Yuriy Semenov [ru], the President of Russian Space Corporation Energia at the time, disapproved of the name "Alpha" as he felt that Mir was the first modular space station, so the names "Beta" or "Mir 2" for the ISS would have been more fitting.[105][107][108] Expedition 1 arrived midway between the Space Shuttle flights of missions STS-92 and STS-97. These two flights each added segments of the station's Integrated Truss Structure, which provided the station with Ku-band communication for US television, additional attitude support needed for the additional mass of the USOS, and substantial solar arrays to supplement the station's four existing arrays.[109] Over the next two years, the station continued to expand. A Soyuz-U rocket delivered the Pirs docking compartment. The Space Shuttles Discovery, Atlantis, and Endeavour delivered the Destiny laboratory and Quest airlock, in addition to the station's main robot arm, the Canadarm2, and several more segments of the Integrated Truss Structure. The expansion schedule was interrupted in 2003 by the Space Shuttle Columbia disaster and a resulting hiatus in flights. The Space Shuttle was grounded until 2005 with STS-114 flown by Discovery.[110] Assembly resumed in 2006 with the arrival of STS-115 with Atlantis, which delivered the station's second set of solar arrays. Several more truss segments and a third set of arrays were delivered on STS-116, STS-117, and STS-118. As a result of the major expansion of the station's power-generating capabilities, more pressurised modules could be accommodated, and the Harmony node and Columbus European laboratory were added. These were soon followed by the first two components of Kibō. In March 2009, STS-119 completed the Integrated Truss Structure with the installation of the fourth and final set of solar arrays. The final section of Kibō was delivered in July 2009 on STS-127, followed by the Russian Poisk module. The third node, Tranquility, was delivered in February 2010 during STS-130 by the Space Shuttle Endeavour, alongside the Cupola, followed by the penultimate Russian module, Rassvet, in May 2010. Rassvet was delivered by Space Shuttle Atlantis on STS-132 in exchange for the Russian Proton delivery of the US-funded Zarya module in 1998.[111] The last pressurised module of the USOS, Leonardo, was brought to the station in February 2011 on the final flight of Discovery, STS-133.[112] The Alpha Magnetic Spectrometer was delivered by Endeavour on STS-134 the same year.[113] By June 2011, the station consisted of 15 pressurised modules and the Integrated Truss Structure. Two power modules called NEM-1 and NEM-2.[114] are still to be launched. Russia's new primary research module Nauka docked in July 2021,[115] along with the European Robotic Arm which will be able to relocate itself to different parts of the Russian modules of the station.[116] Russia's latest addition, the nodal module Prichal, docked in November 2021.[117] The gross mass of the station changes over time. The total launch mass of the modules on orbit is about 417,289 kg (919,965 lb) (as of 3 September 2011).[118] The mass of experiments, spare parts, personal effects, crew, foodstuff, clothing, propellants, water supplies, gas supplies, docked spacecraft, and other items add to the total mass of the station. Hydrogen gas is constantly vented overboard by the oxygen generators. Structure The ISS is a modular space station. Modular stations can allow modules to be added to or removed from the existing structure, allowing greater flexibility.     Technical blueprint of components     Technical blueprint of components     The ISS exterior and steelwork taken on 8 November 2021, from the departing SpaceX Crew-2 capsule     The ISS exterior and steelwork taken on 8 November 2021, from the departing SpaceX Crew-2 capsule     Diagram structure of International Space Station after installation of iROSA solar arrays (as of 2022)     Diagram structure of International Space Station after installation of iROSA solar arrays (as of 2022) Below is a diagram of major station components. The blue areas are pressurised sections accessible by the crew without using spacesuits. The station's unpressurised superstructure is indicated in red. Planned components are shown in white, non installed, temporarily defunct or non-commissioned components are shown in brown and former ones in gray. Other unpressurised components are yellow. The Unity node joins directly to the Destiny laboratory. For clarity, they are shown apart. Similar cases are also seen in other parts of the structure. Zarya (Russian: Заря, lit. 'Dawn'[b]), also known as the Functional Cargo Block or FGB (from the Russian: "Функционально-грузовой блок", lit. 'Funktsionalno-gruzovoy blok' or ФГБ), is the first module of the ISS to have been launched.[119] The FGB provided electrical power, storage, propulsion, and guidance to the ISS during the initial stage of assembly. With the launch and assembly in orbit of other modules with more specialized functionality, Zarya, as of August 2021, is primarily used for storage, both inside the pressurized section and in the externally mounted fuel tanks. The Zarya is a descendant of the TKS spacecraft designed for the Russian Salyut program. The name Zarya ("Dawn") was given to the FGB because it signified the dawn of a new era of international cooperation in space. Although it was built by a Russian company, it is owned by the United States.[120] Unity as seen by Space Shuttle Endeavour during STS-88 Unity Main article: Unity (ISS module) The Unity connecting module, also known as Node 1, is the first U.S.-built component of the ISS. It connects the Russian and U.S. segments of the station, and is where crew eat meals together.[121][122] The module is cylindrical in shape, with six berthing locations (forward, aft, port, starboard, zenith, and nadir) facilitating connections to other modules. Unity measures 4.57 metres (15.0 ft) in diameter, is 5.47 metres (17.9 ft) long, made of steel, and was built for NASA by Boeing in a manufacturing facility at the Marshall Space Flight Center in Huntsville, Alabama. Unity is the first of the three connecting modules; the other two are Harmony and Tranquility.[123] Zvezda as seen by Space Shuttle Endeavour during STS-97 Zvezda Main article: Zvezda (ISS module) Zvezda (Russian: Звезда, meaning "star"), Salyut DOS-8, is also known as the Zvezda Service Module. It was the third module launched to the station, and provides all of the station's life support systems, some of which are supplemented in the USOS, as well as living quarters for two crew members. It is the structural and functional center of the Russian Orbital Segment, which is the Russian part of the ISS. Crew assemble here to deal with emergencies on the station.[124][125][126] The module was manufactured by RKK Energia, with major sub-contracting work by GKNPTs Khrunichev.[127] Zvezda was launched on a Proton rocket on 12 July 2000, and docked with the Zarya module on 26 July 2000. The Destiny module being installed on the ISS Destiny Main article: Destiny (ISS module) The Destiny module, also known as the U.S. Lab, is the primary operating facility for U.S. research payloads aboard the ISS.[128][129] It was berthed to the Unity module and activated over a period of five days in February 2001.[130] Destiny is NASA's first permanent operating orbital research station since Skylab was vacated in February 1974. The Boeing Company began construction of the 14.5-tonne (32,000 lb) research laboratory in 1995 at the Michoud Assembly Facility and then the Marshall Space Flight Center in Huntsville, Alabama.[128] Destiny was shipped to the Kennedy Space Center in Florida in 1998, and was turned over to NASA for pre-launch preparations in August 2000. It launched on 7 February 2001, aboard the Space Shuttle Atlantis on STS-98.[130] Astronauts work inside the pressurized facility to conduct research in numerous scientific fields. Scientists throughout the world would use the results to enhance their studies in medicine, engineering, biotechnology, physics, materials science, and Earth science.[129] Quest Joint Airlock Module Quest Main article: Quest Joint Airlock The Joint Airlock (also known as "Quest") is provided by the U.S. and provides the capability for ISS-based Extravehicular Activity (EVA) using either a U.S. Extravehicular Mobility Unit (EMU) or Russian Orlan EVA suits. Before the launch of this airlock, EVAs were performed from either the U.S. Space Shuttle (while docked) or from the Transfer Chamber on the Service Module. Due to a variety of system and design differences, only U.S. space suits could be used from the Shuttle and only Russian suits could be used from the Service Module. The Joint Airlock alleviates this short-term problem by allowing either (or both) spacesuit systems to be used. The Joint Airlock was launched on ISS-7A / STS-104 in July 2001 and was attached to the right hand docking port of Node 1. The Joint Airlock is 20 ft. long, 13 ft. in diameter, and weighs 6.5 tons. The Joint Airlock was built by Boeing at Marshall Space Flight Center. The Joint Airlock was launched with the High Pressure Gas Assembly. The High Pressure Gas Assembly was mounted on the external surface of the Joint Airlock and will support EVAs operations with breathing gases and augments the Service Module's gas resupply system. The Joint Airlock has two main components: a crew airlock from which astronauts and cosmonauts exit the ISS and an equipment airlock designed for storing EVA gear and for so-called overnight "campouts" wherein Nitrogen is purged from astronaut's bodies overnight as pressure is dropped in preparation for spacewalks the following day. This alleviates the bends as the astronauts are repressurized after their EVA. The crew airlock was derived from the Space Shuttle's external airlock. It is equipped with lighting, external handrails, and an Umbilical Interface Assembly (UIA). The UIA is located on one wall of the crew airlock and provides a water supply line, a wastewater return line, and an oxygen supply line. The UIA also provides communication gear and spacesuit power interfaces and can support two spacesuits simultaneously. This can be either two American EMU spacesuits, two Russian ORLAN spacesuits, or one of each design. Poisk Main article: Poisk (ISS module) Poisk (Russian: По́иск, lit. 'Search') was launched on 10 November 2009[131][132] attached to a modified Progress spacecraft, called Progress M-MIM2, on a Soyuz-U rocket from Launch Pad 1 at the Baikonur Cosmodrome in Kazakhstan. Poisk is used as the Russian airlock module, containing two identical EVA hatches. An outward-opening hatch on the Mir space station failed after it swung open too fast after unlatching, because of a small amount of air pressure remaining in the airlock.[133] All EVA hatches on the ISS open inwards and are pressure-sealing. Poisk is used to store, service, and refurbish Russian Orlan suits and provides contingency entry for crew using the slightly bulkier American suits. The outermost docking port on the module allows docking of Soyuz and Progress spacecraft, and the automatic transfer of propellants to and from storage on the ROS.[134] Since the departure of the identical Pirs module on July 26, 2021, Poisk has served as the only airlock on the ROS. Harmony shown connected to Columbus, Kibo, and Destiny. PMA-2 faces. The nadir and zenith locations are open. Harmony Main article: Harmony (ISS module) Harmony, also known as Node 2, is the "utility hub" of the ISS. It connects the laboratory modules of the United States, Europe and Japan, as well as providing electrical power and electronic data. Sleeping cabins for four of the crew are housed here.[135] Harmony was successfully launched into space aboard Space Shuttle flight STS-120 on 23 October 2007.[136][137] After temporarily being attached to the port side of the Unity node,[138][139] it was moved to its permanent location on the forward end of the Destiny laboratory on 14 November 2007.[140] Harmony added 75.5 m3 (2,666 cu ft) to the station's living volume, an increase of almost 20 percent, from 424.8 to 500.2 m3 (15,000 to 17,666 cu ft). Its successful installation meant that from NASA's perspective, the station was considered to be "U.S. Core Complete". Tranquility in 2011 Tranquility Main article: Tranquility (ISS module) Tranquility, also known as Node 3, is a module of the ISS. It contains environmental control systems, life support systems, a toilet, exercise equipment, and an observation cupola. The European Space Agency and the Italian Space Agency had Tranquility manufactured by Thales Alenia Space. A ceremony on 20 November 2009 transferred ownership of the module to NASA.[141] On 8 February 2010, NASA launched the module on the Space Shuttle's STS-130 mission. The Columbus module on the ISS Columbus Main article: Columbus (ISS module) Columbus is a science laboratory that is part of the ISS and is the largest single contribution to the station made by the European Space Agency. Like the Harmony and Tranquility modules, the Columbus laboratory was constructed in Turin, Italy by Thales Alenia Space. The functional equipment and software of the lab was designed by EADS in Bremen, Germany. It was also integrated in Bremen before being flown to the Kennedy Space Center in Florida in an Airbus Beluga. It was launched aboard Space Shuttle Atlantis on 7 February 2008, on flight STS-122. It is designed for ten years of operation. The module is controlled by the Columbus Control Centre, located at the German Space Operations Center, part of the German Aerospace Center in Oberpfaffenhofen near Munich, Germany. The European Space Agency has spent €1.4 billion (about US$2 billion) on building Columbus, including the experiments it carries and the ground control infrastructure necessary to operate them.[142] Kibō Exposed Facility on the right Kibō Main article: Kibō (ISS module) The Japanese Experiment Module (JEM), nicknamed Kibō (きぼう, Kibō, Hope), is a Japanese science module for the International Space Station (ISS) developed by JAXA. It is the largest single ISS module, and is attached to the Harmony module. The first two pieces of the module were launched on Space Shuttle missions STS-123 and STS-124. The third and final components were launched on STS-127.[143] The Cupola's windows with shutters open Cupola Main article: Cupola (ISS module) The Cupola is an ESA-built observatory module of the ISS. Its name derives from the Italian word cupola, which means "dome". Its seven windows are used to conduct experiments, dockings and observations of Earth. It was launched aboard Space Shuttle mission STS-130 on 8 February 2010 and attached to the Tranquility (Node 3) module. With the Cupola attached, ISS assembly reached 85 percent completion. The Cupola's central window has a diameter of 80 cm (31 in).[144] Rassvet module with MLM-outfitting equipment (consisting of experiment airlock, RTOd radiators, and ERA workpost) at KSC Rassvet Main article: Rassvet (ISS module) Rassvet (Russian: Рассвет; lit. "dawn"), also known as the Mini-Research Module 1 (MRM-1) (Russian: Малый исследовательский модуль, МИМ 1) and formerly known as the Docking Cargo Module (DCM), is a component of the International Space Station (ISS). The module's design is similar to the Mir Docking Module launched on STS-74 in 1995. Rassvet is primarily used for cargo storage and as a docking port for visiting spacecraft. It was flown to the ISS aboard Space Shuttle Atlantis on the STS-132 mission on 14 May 2010,[145] and was connected to the ISS on 18 May 2010.[146] The hatch connecting Rassvet with the ISS was first opened on 20 May 2010.[147] On 28 June 2010, the Soyuz TMA-19 spacecraft performed the first docking with the module.[148] MLM outfittings MLM outfittings on Rassvet A wide-angle view of the new module (behind Rassvet) attached to the ROS as seen from the cupola In May 2010, equipment for Nauka was launched on STS-132 (as part of an agreement with NASA) and delivered by Space Shuttle Atlantis. Weighing 1.4 metric tons, the equipment was attached to the outside of Rassvet (MRM-1). It included a spare elbow joint for the European Robotic Arm (ERA) (which was launched with Nauka) and an ERA-portable workpost used during EVAs, as well as RTOd add-on heat radiator, internal hardware and an experiment airlock for launching CubeSats to be positioned on the modified passive forward port near the nadir end of the Nauka module.[149] Modified passive forward port for experiment airlock near the nadir end of Nauka The RTOd radiator adds additional cooling capability to Nauka, which enables the module to host more scientific experiments. The airlock will be used only to pass experiments inside and outside the module, with the aid of ERA – very similar to the Japanese airlock and Nanoracks Bishop Airlock on the U.S. segment of the station.[149] The ERA was used to remove the RTOd radiator and will be used to remove airlock Shk from Rassvet and transfer them over to Nauka. This process took several months. A portable work platform will also be transferred over in near future, which can attach to the end of the ERA to allow cosmonauts to "ride" on the end of the arm during spacewalks.[150] Another MLM outfitting is a 4 segment external payload interface called means of attachment of large payloads (Sredstva Krepleniya Krupnogabaritnykh Obyektov, SKKO).[151] Delivered in two parts to Nauka by Progress MS-18 (LCCS part) and Progress MS-21 (SCCCS part) as part of the module activation outfitting process.[152][153][154][155] It was taken outside and installed on the ERA aft facing base point on Nauka during the VKD-55 spacewalk.[156] Leonardo Permanent Multipurpose Module Leonardo Main article: Leonardo (ISS module) The Leonardo Permanent Multipurpose Module (PMM) is a module of the International Space Station. It was flown into space aboard the Space Shuttle on STS-133 on 24 February 2011 and installed on 1 March. Leonardo is primarily used for storage of spares, supplies and waste on the ISS, which was until then stored in many different places within the space station. It is also the personal hygiene area for the astronauts who live in the US Orbital Segment. The Leonardo PMM was a Multi-Purpose Logistics Module (MPLM) before 2011, but was modified into its current configuration. It was formerly one of two MPLM used for bringing cargo to and from the ISS with the Space Shuttle. The module was named for Italian polymath Leonardo da Vinci. Bigelow Expandable Activity Module Progression of the expansion of BEAM The Bigelow Expandable Activity Module (BEAM) is an experimental expandable space station module developed by Bigelow Aerospace, under contract to NASA, for testing as a temporary module on the International Space Station (ISS) from 2016 to at least 2020. It arrived at the ISS on 10 April 2016,[157] was berthed to the station on 16 April at Tranquility Node 3, and was expanded and pressurized on 28 May 2016. IDA-1 upright International Docking Adapters The International Docking Adapter (IDA) is a spacecraft docking system adapter developed to convert APAS-95 to the NASA Docking System (NDS). An IDA is placed on each of the ISS's two open Pressurized Mating Adapters (PMAs), both of which are connected to the Harmony module. Two International Docking Adapters are currently installed aboard the Station. Originally, IDA-1 was planned to be installed on PMA-2, located at Harmony's forward port, and IDA-2 would be installed on PMA-3 at Harmony's zenith. After IDA 1 was destroyed in a launch incident, IDA-2 was installed on PMA-2 on 19 August 2016,[158] while IDA-3 was later installed on PMA-3 on 21 August 2019.[159] NanoRacks Bishop airlock module installed on the ISS Bishop Airlock Module Main article: Nanoracks Bishop Airlock The NanoRacks Bishop Airlock Module is a commercially funded airlock module launched to the ISS on SpaceX CRS-21 on 6 December 2020.[160][161] The module was built by NanoRacks, Thales Alenia Space, and Boeing.[162] It will be used to deploy CubeSats, small satellites, and other external payloads for NASA, CASIS, and other commercial and governmental customers.[163] Nauka Main article: Nauka (ISS module) Nauka (Russian: Наука, lit. 'Science'), also known as the Multipurpose Laboratory Module-Upgrade (MLM-U), (Russian: Многоцелевой лабораторный модуль, усоверше́нствованный, or МЛМ-У), is a Roscosmos-funded component of the ISS that was launched on 21 July 2021, 14:58 UTC. In the original ISS plans, Nauka was to use the location of the Docking and Stowage Module (DSM), but the DSM was later replaced by the Rassvet module and moved to Zarya's nadir port. Nauka was successfully docked to Zvezda's nadir port on 29 July 2021, 13:29 UTC, replacing the Pirs module. Progress MS-17 undocking and taking the Nauka nadir temporary docking adapter with it[c][d] It had a temporary docking adapter on its nadir port for crewed and uncrewed missions until Prichal arrival, where just before its arrival it was removed by a departing Progress spacecraft.[164] Nauka and Prichal docked to ISS Prichal Main article: Prichal (ISS module) Prichal, also known as Uzlovoy Module or UM (Russian: Узловой Модуль Причал, lit. 'Nodal Module Berth'),[165] is a 4-tonne (8,800 lb)[166] ball-shaped module that will provide the Russian segment additional docking ports to receive Soyuz MS and Progress MS spacecraft. UM was launched in November 2021.[167] It was integrated with a special version of the Progress cargo spacecraft and launched by a standard Soyuz rocket, docking to the nadir port of the Nauka module. One port is equipped with an active hybrid docking port, which enables docking with the MLM module. The remaining five ports are passive hybrids, enabling docking of Soyuz and Progress vehicles, as well as heavier modules and future spacecraft with modified docking systems. The node module was intended to serve as the only permanent element of the cancelled Orbital Piloted Assembly and Experiment Complex (OPSEK).[167][168][169] Unpressurised elements ISS Truss Components breakdown showing Trusses and all ORUs in situ The ISS has a large number of external components that do not require pressurisation. The largest of these is the Integrated Truss Structure (ITS), to which the station's main solar arrays and thermal radiators are mounted.[170] The ITS consists of ten separate segments forming a structure 108.5 metres (356 ft) long.[6] The station was intended to have several smaller external components, such as six robotic arms, three External Stowage Platforms (ESPs) and four ExPRESS Logistics Carriers (ELCs).[171][172] While these platforms allow experiments (including MISSE, the STP-H3 and the Robotic Refueling Mission) to be deployed and conducted in the vacuum of space by providing electricity and processing experimental data locally, their primary function is to store spare Orbital Replacement Units (ORUs). ORUs are parts that can be replaced when they fail or pass their design life, including pumps, storage tanks, antennas, and battery units. Such units are replaced either by astronauts during EVA or by robotic arms.[173] Several shuttle missions were dedicated to the delivery of ORUs, including STS-129,[174] STS-133[175] and STS-134.[176] As of January 2011, only one other mode of transportation of ORUs had been utilised – the Japanese cargo vessel HTV-2 – which delivered an FHRC and CTC-2 via its Exposed Pallet (EP).[177][needs update] Construction of the Integrated Truss Structure over New Zealand There are also smaller exposure facilities mounted directly to laboratory modules; the Kibō Exposed Facility serves as an external "porch" for the Kibō complex,[178] and a facility on the European Columbus laboratory provides power and data connections for experiments such as the European Technology Exposure Facility[179][180] and the Atomic Clock Ensemble in Space.[181] A remote sensing instrument, SAGE III-ISS, was delivered to the station in February 2017 aboard CRS-10,[182] and the NICER experiment was delivered aboard CRS-11 in June 2017.[183] The largest scientific payload externally mounted to the ISS is the Alpha Magnetic Spectrometer (AMS), a particle physics experiment launched on STS-134 in May 2011, and mounted externally on the ITS. The AMS measures cosmic rays to look for evidence of dark matter and antimatter.[184][185] The commercial Bartolomeo External Payload Hosting Platform, manufactured by Airbus, was launched on 6 March 2020 aboard CRS-20 and attached to the European Columbus module. It will provide an additional 12 external payload slots, supplementing the eight on the ExPRESS Logistics Carriers, ten on Kibō, and four on Columbus. The system is designed to be robotically serviced and will require no astronaut intervention. It is named after Christopher Columbus's younger brother.[186][187][188] Robotic arms and cargo cranes Commander Volkov stands on Pirs with his back to the Soyuz whilst operating the manual Strela crane (which is holding photographer Oleg Kononenko). Dextre, like many of the station's experiments and robotic arms, can be operated from Earth, allowing tasks to be performed while the crew sleeps. The Integrated Truss Structure serves as a base for the station's primary remote manipulator system, the Mobile Servicing System (MSS), which is composed of three main components:     Canadarm2, the largest robotic arm on the ISS, has a mass of 1,800 kilograms (4,000 lb) and is used to: dock and manipulate spacecraft and modules on the USOS; hold crew members and equipment in place during EVAs; and move Dextre around to perform tasks.[189]     Dextre is a 1,560 kg (3,440 lb) robotic manipulator that has two arms and a rotating torso, with power tools, lights, and video for replacing orbital replacement units (ORUs) and performing other tasks requiring fine control.[190]     The Mobile Base System (MBS) is a platform that rides on rails along the length of the station's main truss, which serves as a mobile base for Canadarm2 and Dextre, allowing the robotic arms to reach all parts of the USOS.[191] A grapple fixture was added to Zarya on STS-134 to enable Canadarm2 to inchworm itself onto the Russian Orbital Segment.[192] Also installed during STS-134 was the 15 m (50 ft) Orbiter Boom Sensor System (OBSS), which had been used to inspect heat shield tiles on Space Shuttle missions and which can be used on the station to increase the reach of the MSS.[192] Staff on Earth or the ISS can operate the MSS components using remote control, performing work outside the station without the need for space walks. Japan's Remote Manipulator System, which services the Kibō Exposed Facility,[193] was launched on STS-124 and is attached to the Kibō Pressurised Module.[194] The arm is similar to the Space Shuttle arm as it is permanently attached at one end and has a latching end effector for standard grapple fixtures at the other. The European Robotic Arm, which will service the Russian Orbital Segment, was launched alongside the Nauka module.[195] The ROS does not require spacecraft or modules to be manipulated, as all spacecraft and modules dock automatically and may be discarded the same way. Crew use the two Strela (Russian: Стрела́, lit. 'Arrow') cargo cranes during EVAs for moving crew and equipment around the ROS. Each Strela crane has a mass of 45 kg (99 lb). Former module Pirs Main article: Pirs (ISS module) Pirs (Russian: Пирс, lit. 'Pier') was launched on 14 September 2001, as ISS Assembly Mission 4R, on a Russian Soyuz-U rocket, using a modified Progress spacecraft, Progress M-SO1, as an upper stage. Pirs was undocked by Progress MS-16 on 26 July 2021, 10:56 UTC, and deorbited on the same day at 14:51 UTC to make room for Nauka module to be attached to the space station. Prior to its departure, Pirs served as the primary Russian airlock on the station, being used to store and refurbish the Russian Orlan spacesuits. The Pirs module attached to the ISS ISS-65 Pirs docking compartment separates from the Space Station. Planned components Axiom segment Main article: Axiom Orbital Segment In January 2020, NASA awarded Axiom Space a contract to build a commercial module for the ISS with a launch date of 2024. The contract is under the NextSTEP2 program. NASA negotiated with Axiom on a firm fixed-price contract basis to build and deliver the module, which will attach to the forward port of the space station's Harmony (Node 2) module. Although NASA has only commissioned one module, Axiom plans to build an entire segment consisting of five modules, including a node module, an orbital research and manufacturing facility, a crew habitat, and a "large-windowed Earth observatory". The Axiom segment is expected to greatly increase the capabilities and value of the space station, allowing for larger crews and private spaceflight by other organisations. Axiom plans to convert the segment into a stand-alone space station once the ISS is decommissioned, with the intention that this would act as a successor to the ISS.[196][197][198] Canadarm 2 will also help to berth the Axiom Space Station modules to the ISS and will continue its operations on the Axiom Space Station after the retirement of ISS in late 2020s.[199] Proposed components Xbase Main article: B330 Made by Bigelow Aerospace. In August 2016 Bigelow negotiated an agreement with NASA to develop a full-sized ground prototype Deep Space Habitation based on the B330 under the second phase of Next Space Technologies for Exploration Partnerships. The module is called the Expandable Bigelow Advanced Station Enhancement (XBASE), as Bigelow hopes to test the module by attaching it to the International Space Station. Independence-1 Nanoracks, after finalizing its contract with NASA, and after winning NextSTEPs Phase II award, is now developing its concept Independence-1 (previously known as Ixion), which would turn spent rocket tanks into a habitable living area to be tested in space. In Spring 2018, Nanoracks announced that Ixion is now known as the Independence-1, the first 'outpost' in Nanoracks' Space Outpost Program. Nautilus-X Centrifuge Demonstration Main article: Nautilus-X If produced, this centrifuge will be the first in-space demonstration of sufficient scale centrifuge for artificial partial-g effects. It will be designed to become a sleep module for the ISS crew. Cancelled components The cancelled Habitation module under construction at Michoud in 1997 Several modules planned for the station were cancelled over the course of the ISS programme. Reasons include budgetary constraints, the modules becoming unnecessary, and station redesigns after the 2003 Columbia disaster. The US Centrifuge Accommodations Module would have hosted science experiments in varying levels of artificial gravity.[200] The US Habitation Module would have served as the station's living quarters. Instead, the living quarters are now spread throughout the station.[201] The US Interim Control Module and ISS Propulsion Module would have replaced the functions of Zvezda in case of a launch failure.[202] Two Russian Research Modules were planned for scientific research.[203] They would have docked to a Russian Universal Docking Module.[204] The Russian Science Power Platform would have supplied power to the Russian Orbital Segment independent of the ITS solar arrays. Science Power Modules 1 and 2 (Repurposed Components) Science Power Module 1 (SPM-1, also known as NEM-1) and Science Power Module 2 (SPM-2, also known as NEM-2) are modules that were originally planned to arrive at the ISS no earlier than 2024, and dock to the Prichal module, which is currently docked to the Nauka module.[169][205] In April 2021, Roscosmos announced that NEM-1 would be repurposed to function as the core module of the proposed Russian Orbital Service Station (ROSS), launching no earlier than 2027[206] and docking to the free-flying Nauka module either before or after the ISS has been deorbited.[207][208] NEM-2 may be converted into another core "base" module, which would be launched in 2028.[209] Onboard systems Life support Main articles: ISS ECLSS and Chemical oxygen generator The critical systems are the atmosphere control system, the water supply system, the food supply facilities, the sanitation and hygiene equipment, and fire detection and suppression equipment. The Russian Orbital Segment's life support systems are contained in the Zvezda service module. Some of these systems are supplemented by equipment in the USOS. The Nauka laboratory has a complete set of life support systems. Atmospheric control systems A flowchart diagram showing the components of the ISS life support system. The interactions between the components of the ISS Environmental Control and Life Support System (ECLSS) The atmosphere on board the ISS is similar to that of Earth.[210] Normal air pressure on the ISS is 101.3 kPa (14.69 psi);[211] the same as at sea level on Earth. An Earth-like atmosphere offers benefits for crew comfort, and is much safer than a pure oxygen atmosphere, because of the increased risk of a fire such as that responsible for the deaths of the Apollo 1 crew.[212][better source needed] Earth-like atmospheric conditions have been maintained on all Russian and Soviet spacecraft.[213] The Elektron system aboard Zvezda and a similar system in Destiny generate oxygen aboard the station.[214] The crew has a backup option in the form of bottled oxygen and Solid Fuel Oxygen Generation (SFOG) canisters, a chemical oxygen generator system.[215] Carbon dioxide is removed from the air by the Vozdukh system in Zvezda. Other by-products of human metabolism, such as methane from the intestines and ammonia from sweat, are removed by activated charcoal filters.[215] Part of the ROS atmosphere control system is the oxygen supply. Triple-redundancy is provided by the Elektron unit, solid fuel generators, and stored oxygen. The primary supply of oxygen is the Elektron unit which produces O2 and H2 by electrolysis of water and vents H2 overboard. The 1 kW (1.3 hp) system uses approximately one litre of water per crew member per day. This water is either brought from Earth or recycled from other systems. Mir was the first spacecraft to use recycled water for oxygen production. The secondary oxygen supply is provided by burning oxygen-producing Vika cartridges (see also ISS ECLSS). Each 'candle' takes 5–20 minutes to decompose at 450–500 °C (842–932 °F), producing 600 litres (130 imp gal; 160 US gal) of O2. This unit is manually operated.[216] The US Orbital Segment has redundant supplies of oxygen, from a pressurised storage tank on the Quest airlock module delivered in 2001, supplemented ten years later by ESA-built Advanced Closed-Loop System (ACLS) in the Tranquility module (Node 3), which produces O2 by electrolysis.[217] Hydrogen produced is combined with carbon dioxide from the cabin atmosphere and converted to water and methane. Power and thermal control Main articles: Electrical system of the International Space Station and External Active Thermal Control System Russian solar arrays, backlit by sunset One of the eight truss mounted pairs of USOS solar arrays ISS new roll out solar array as seen from a zoom camera on the P6 Truss Double-sided solar arrays provide electrical power to the ISS. These bifacial cells collect direct sunlight on one side and light reflected off from the Earth on the other, and are more efficient and operate at a lower temperature than single-sided cells commonly used on Earth.[218] The Russian segment of the station, like most spacecraft, uses 28 V low voltage DC from two rotating solar arrays mounted on Zvezda. The USOS uses 130–180 V DC from the USOS PV array, power is stabilised and distributed at 160 V DC and converted to the user-required 124 V DC. The higher distribution voltage allows smaller, lighter conductors, at the expense of crew safety. The two station segments share power with converters. The USOS solar arrays are arranged as four wing pairs, for a total production of 75 to 90 kilowatts.[219] These arrays normally track the Sun to maximise power generation. Each array is about 375 m2 (4,036 sq ft) in area and 58 m (190 ft) long. In the complete configuration, the solar arrays track the Sun by rotating the alpha gimbal once per orbit; the beta gimbal follows slower changes in the angle of the Sun to the orbital plane. The Night Glider mode aligns the solar arrays parallel to the ground at night to reduce the significant aerodynamic drag at the station's relatively low orbital altitude.[220] The station originally used rechargeable nickel–hydrogen batteries (NiH2) for continuous power during the 45 minutes of every 90-minute orbit that it is eclipsed by the Earth. The batteries are recharged on the day side of the orbit. They had a 6.5-year lifetime (over 37,000 charge/discharge cycles) and were regularly replaced over the anticipated 20-year life of the station.[221] Starting in 2016, the nickel–hydrogen batteries were replaced by lithium-ion batteries, which are expected to last until the end of the ISS program.[222] The station's large solar panels generate a high potential voltage difference between the station and the ionosphere. This could cause arcing through insulating surfaces and sputtering of conductive surfaces as ions are accelerated by the spacecraft plasma sheath. To mitigate this, plasma contactor units create current paths between the station and the ambient space plasma.[223] ISS External Active Thermal Control System (EATCS) diagram The station's systems and experiments consume a large amount of electrical power, almost all of which is converted to heat. To keep the internal temperature within workable limits, a passive thermal control system (PTCS) is made of external surface materials, insulation such as MLI, and heat pipes. If the PTCS cannot keep up with the heat load, an External Active Thermal Control System (EATCS) maintains the temperature. The EATCS consists of an internal, non-toxic, water coolant loop used to cool and dehumidify the atmosphere, which transfers collected heat into an external liquid ammonia loop. From the heat exchangers, ammonia is pumped into external radiators that emit heat as infrared radiation, then back to the station.[224] The EATCS provides cooling for all the US pressurised modules, including Kibō and Columbus, as well as the main power distribution electronics of the S0, S1 and P1 trusses. It can reject up to 70 kW. This is much more than the 14 kW of the Early External Active Thermal Control System (EEATCS) via the Early Ammonia Servicer (EAS), which was launched on STS-105 and installed onto the P6 Truss.[225] Communications and computers Main articles: Tracking and Data Relay Satellite and Luch (satellite) See also: ThinkPad § Use in space Diagram showing communications links between the ISS and other elements. The communications systems used by the ISS * Luch and the Space Shuttle are not in use as of 2020. Radio communications provide telemetry and scientific data links between the station and mission control centres. Radio links are also used during rendezvous and docking procedures and for audio and video communication between crew members, flight controllers and family members. As a result, the ISS is equipped with internal and external communication systems used for different purposes.[226] The Russian Orbital Segment communicates directly with the ground via the Lira antenna mounted to Zvezda.[9][227] The Lira antenna also has the capability to use the Luch data relay satellite system.[9] This system fell into disrepair during the 1990s, and so was not used during the early years of the ISS,[9][228][229] although two new Luch satellites – Luch-5A and Luch-5B – were launched in 2011 and 2012 respectively to restore the operational capability of the system.[230] Another Russian communications system is the Voskhod-M, which enables internal telephone communications between Zvezda, Zarya, Pirs, Poisk, and the USOS and provides a VHF radio link to ground control centres via antennas on Zvezda's exterior.[231] The US Orbital Segment (USOS) makes use of two separate radio links: S band (audio, telemetry, commanding – located on the P1/S1 truss) and Ku band (audio, video and data – located on the Z1 truss) systems. These transmissions are routed via the United States Tracking and Data Relay Satellite System (TDRSS) in geostationary orbit, allowing for almost continuous real-time communications with Christopher C. Kraft Jr. Mission Control Center (MCC-H) in Houston.[9][29][226] Data channels for the Canadarm2, European Columbus laboratory and Japanese Kibō modules were originally also routed via the S band and Ku band systems, with the European Data Relay System and a similar Japanese system intended to eventually complement the TDRSS in this role.[29][232] Communications between modules are carried on an internal wireless network.[233] An array of laptops in the US lab Laptop computers surround the Canadarm2 console. An error message displays a problem with hard drive on ISS laptop. UHF radio is used by astronauts and cosmonauts conducting EVAs and other spacecraft that dock to or undock from the station.[9] Automated spacecraft are fitted with their own communications equipment; the ATV uses a laser attached to the spacecraft and the Proximity Communications Equipment attached to Zvezda to accurately dock with the station.[234][235] The ISS is equipped with about 100 IBM/Lenovo ThinkPad and HP ZBook 15 laptop computers. The laptops have run Windows 95, Windows 2000, Windows XP, Windows 7, Windows 10 and Linux operating systems.[236] Each computer is a commercial off-the-shelf purchase which is then modified for safety and operation including updates to connectors, cooling and power to accommodate the station's 28V DC power system and weightless environment. Heat generated by the laptops does not rise but stagnates around the laptop, so additional forced ventilation is required. Portable Computer System (PCS) laptops connect to the Primary Command & Control computer (C&C MDM) as remote terminals via a USB to 1553 adapter.[237] Station Support Computer (SSC) laptops aboard the ISS are connected to the station's wireless LAN via Wi-Fi and ethernet, which connects to the ground via Ku band. While originally this provided speeds of 10 Mbit/s download and 3 Mbit/s upload from the station,[238][239] NASA upgraded the system in late August 2019 and increased the speeds to 600 Mbit/s.[240][241] Laptop hard drives occasionally fail and must be replaced.[242] Other computer hardware failures include instances in 2001, 2007 and 2017; some of these failures have required EVAs to replace computer modules in externally mounted devices.[243][244][245][246] The operating system used for key station functions is the Debian Linux distribution.[247] The migration from Microsoft Windows to Linux was made in May 2013 for reasons of reliability, stability and flexibility.[248] In 2017, an SG100 Cloud Computer was launched to the ISS as part of OA-7 mission.[249] It was manufactured by NCSIST of Taiwan and designed in collaboration with Academia Sinica, and National Central University under contract for NASA.[250] ISS crew members have access to the Internet, and thus the web.[251][252] This was first enabled in 2010,[251] allowing NASA astronaut T.J. Creamer to make the first tweet from space.[253] Access is achieved via an Internet-enabled computer in Houston, using remote desktop mode, thereby protecting the ISS from virus infection and hacking attempts.[251] Operations Expeditions See also: List of International Space Station expeditions Zarya and Unity were entered for the first time on 10 December 1998. Soyuz TM-31 being prepared to bring the first resident crew to the station in October 2000 Each permanent crew is given an expedition number. Expeditions run up to six months, from launch until undocking, an 'increment' covers the same time period, but includes cargo spacecraft and all activities. Expeditions 1 to 6 consisted of three-person crews. Expeditions 7 to 12 were reduced to the safe minimum of two following the destruction of the NASA Shuttle Columbia. From Expedition 13 the crew gradually increased to six around 2010.[254][255] With the arrival of crew on US commercial vehicles beginning in 2020,[256] NASA has indicated that expedition size may be increased to seven crew members, the number ISS was originally designed for.[257][258] Gennady Padalka, member of Expeditions 9, 19/20, 31/32, and 43/44, and Commander of Expedition 11, has spent more time in space than anyone else, a total of 878 days, 11 hours, and 29 minutes.[259] Peggy Whitson has spent the most time in space of any American, totalling 665 days, 22 hours, and 22 minutes during her time on Expeditions 5, 16, and 50/51/52.[260] Private flights See also: Space tourism Travellers who pay for their own passage into space are termed spaceflight participants by Roscosmos and NASA, and are sometimes referred to as "space tourists", a term they generally dislike.[e] As of 2021, seven space tourists have visited the ISS; all seven were transported to the ISS on Russian Soyuz spacecraft. When professional crews change over in numbers not divisible by the three seats in a Soyuz, and a short-stay crewmember is not sent, the spare seat is sold by MirCorp through Space Adventures. Space tourism was halted in 2011 when the Space Shuttle was retired and the station's crew size was reduced to six, as the partners relied on Russian transport seats for access to the station. Soyuz flight schedules increased after 2013, allowing five Soyuz flights (15 seats) with only two expeditions (12 seats) required.[268] The remaining seats were to be sold for around US$40 million to members of the public who could pass a medical exam. ESA and NASA criticised private spaceflight at the beginning of the ISS, and NASA initially resisted training Dennis Tito, the first person to pay for his own passage to the ISS.[f] Anousheh Ansari became the first self-funded woman to fly to the ISS as well as the first Iranian in space. Officials reported that her education and experience made her much more than a tourist, and her performance in training had been "excellent."[269] She did Russian and European studies involving medicine and microbiology during her 10-day stay. The 2009 documentary Space Tourists follows her journey to the station, where she fulfilled "an age-old dream of man: to leave our planet as a 'normal person' and travel into outer space."[270] In 2008, spaceflight participant Richard Garriott placed a geocache aboard the ISS during his flight.[271] This is currently the only non-terrestrial geocache in existence.[272] At the same time, the Immortality Drive, an electronic record of eight digitised human DNA sequences, was placed aboard the ISS.[273] Fleet operations Dragon and Cygnus cargo vessels were docked at the ISS together for the first time in April 2016. Japan's Kounotori 4 berthing Commercial Crew Program vehicles Starliner and Dragon A wide variety of crewed and uncrewed spacecraft have supported the station's activities. Flights to the ISS include 37 Space Shuttle missions, 83 Progress resupply spacecraft (including the modified M-MIM2, M-SO1 and M-UM module transports), 63 crewed Soyuz spacecraft, 5 European ATVs, 9 Japanese HTVs, 1 Boeing Starliner, 30 SpaceX Dragon ( both crewed and uncrewed) and 18 Cygnus missions.[274] As of 30 December 2021, 256 people from 20 countries had visited the space station, many of them multiple times. The United States sent 158 people, Russia sent 55, 11 were Japanese, nine were Canadian, five were Italian, four were French, four were German, and there were one each from Belgium, Brazil, Denmark, Great Britain, Kazakhstan, Malaysia, the Netherlands, South Africa, South Korea, Spain, Israel, Sweden and the United Arab Emirates.[277] Uncrewed Uncrewed spaceflights to the ISS are made primarily to deliver cargo, however several Russian modules have also docked to the outpost following uncrewed launches. Resupply missions typically use the Russian Progress spacecraft, former European ATVs, Japanese Kounotori vehicles, and the American Dragon and Cygnus spacecraft. The primary docking system for Progress spacecraft is the automated Kurs system, with the manual TORU system as a backup. ATVs also used Kurs, however they were not equipped with TORU. Progress and former ATV can remain docked for up to six months.[278][279] The other spacecraft – the Japanese HTV, the SpaceX Dragon (under CRS phase 1), and the Northrop Grumman[280] Cygnus – rendezvous with the station before being grappled using Canadarm2 and berthed at the nadir port of the Harmony or Unity module for one to two months. Under CRS phase 2, Cargo Dragon docks autonomously at IDA-2 or IDA-3. As of December 2020, Progress spacecraft have flown most of the uncrewed missions to the ISS. Soyuz MS-22 was launched in 2022. A micro-meteorite impact in December 2022 caused a coolant leak in its external radiator and it was considered risky for human landing. Thus MS-22 reentered uncrewed on 28 March 2023 and Soyuz MS-23 was launched uncrewed on 24 February 2023, to return the MS-22 crew.[281][282][283] Currently docked/berthed Rendering of the ISS Visiting Vehicle Launches, Arrivals and Departures. Live link at nasa.gov. Spacecraft     Type     Mission     Location     Arrival (UTC)     Departure (planned) Progress MS No. 452     Russia     Uncrewed     Progress MS-22     Zvezda aft     11 February 2023     21 August 2023 Soyuz MS No. 754     Russia     Crewed/ Uncrewed     Soyuz MS-23     Prichal nadir     26 February 2023     27 September 2023 Crew Dragon Endeavour     United States     Crewed     Crew-6     Harmony zenith     3 March 2023     27 August 2023 Modules/spacecraft pending relocation/installation Modules and spacecraft     Type     Current location     Relocated location     Relocation date (planned) Nauka Experiment Airlock     Russia     Module     Rassvet starboard     Nauka forward port     25 April 2023 ERA Portable Workpost     Russia     Module     Rassvet forward     Nauka forward     2023 Scheduled missions     All dates are UTC. Dates are the earliest possible dates and may change.     Forward ports are at the front of the station according to its normal direction of travel and orientation (attitude). Aft is at the rear of the station, used by spacecraft boosting the station's orbit. Nadir is closest the Earth, zenith is on top. Port is to the left if pointing one's feet towards the Earth and looking in the direction of travel; starboard to the right. Mission     Launch date (NET)     Spacecraft     Type     Launch vehicle     Launch site     Launch provider     Docking/berthing port NG-19     6 May 2023[284][285]     Cygnus     Uncrewed     Antares 230+     United States Wallops Pad OA     United States Northrop Grumman     Unity nadir AX-2     9 May 2023     Crew Dragon     Crewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Harmony forward Progress MS-23     24 May 2023[284][286]     Progress MS No. 453     Uncrewed     Soyuz-2.1a     Kazakhstan Baikonur Site 31/6     Russia Roscosmos     Poisk zenith SpX-28     1 June 2023[284][285]     Cargo Dragon     Uncrewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Harmony forward Module Boe-CFT     21 July 2023[287][284][285][288]     Boeing Starliner Calypso     Crewed     Atlas V N22     United States Cape Canaveral SLC-41     United States United Launch Alliance     Harmony forward SpaceX Crew-7     17 August 2023     Dragon 2     Crewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Harmony forward or zenith Progress MS-24     23 August 2023[284][286]     Progress MS No. 454     Uncrewed     Soyuz-2.1a     Kazakhstan Baikonur Site 31/6     Russia Roscosmos     Zvezda aft Soyuz MS-24     15 September 2023     Soyuz MS     Crewed     Soyuz-2.1a     Kazakhstan Baikonur Site 31/6     Russia Roscosmos     Rassvet nadir NG-20     November 2023[284][285]     Cygnus     Uncrewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Unity nadir AX-3     November 2023     Crew Dragon     Crewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Harmony zenith Progress MS-25     1 December 2023[284][286]     Progress MS No. 455     Uncrewed     Soyuz-2.1a     Kazakhstan Baikonur Site 31/6     Russia Roscosmos     Prichal nadir SNC-1     15 December 2023[284][285][289]     Dream Chaser Tenacity     Uncrewed     Vulcan Centaur VC4L     United States Cape Canaveral SLC-41     United States United Launch Alliance     Harmony nadir SpX-29     December 2023[284][285]     Cargo Dragon     Uncrewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Harmony zenith HTV-X1     3 January 2024[284]     HTV-X     Uncrewed     H3-24L     Japan Tanegashima LA-Y2     Japan JAXA     Harmony nadir SpaceX Crew-8     February 2023     Dragon 2     Crewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Harmony forward or zenith Progress MS-26     February 2024[284][286]     Progress MS No. 456     Uncrewed     Soyuz-2.1a     Kazakhstan Baikonur Site 31/6     Russia Roscosmos     Zvezda aft Soyuz MS-25     13 March 2023     Soyuz MS     Crewed     Soyuz-2.1a     Kazakhstan Baikonur Site 31/6     Russia Roscosmos     Prichal nadir AX-4     H1 2024     Crew Dragon     Crewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Harmony forward NG-21     April 2024[284][285]     Cygnus     Uncrewed     Falcon 9 Block 5     United States Kennedy LC-39A     United States SpaceX     Unity nadir Progress MS-27     June 2024[284][286]     Progress MS No. 457     Uncrewed     Soyuz-2.1a     Kazakhstan Baikonur Site 31/6     Russia Roscosmos     Poisk zenith Starliner-1     Q3 2024[284][285]     Boeing Starliner SC-2     Crewed     Atlas V N22     United States Cape Canaveral SLC-41     United States United Launch Alliance     Harmony forward Docking See also: Docking and berthing of spacecraft The Progress M-14M resupply vehicle approaching the ISS in 2012. More than 50 unpiloted Progress spacecraft have delivered supplies during the lifetime of the station. Space Shuttle Endeavour, ATV-2, Soyuz TMA-21, and Progress M-10M docked to the ISS, as seen from the departing Soyuz TMA-20 All Russian spacecraft and self-propelled modules are able to rendezvous and dock to the space station without human intervention using the Kurs radar docking system from over 200 kilometres away. The European ATV uses star sensors and GPS to determine its intercept course. When it catches up it uses laser equipment to optically recognise Zvezda, along with the Kurs system for redundancy. Crew supervise these craft, but do not intervene except to send abort commands in emergencies. Progress and ATV supply craft can remain at the ISS for six months,[290][291] allowing great flexibility in crew time for loading and unloading of supplies and trash. From the initial station programs, the Russians pursued an automated docking methodology that used the crew in override or monitoring roles. Although the initial development costs were high, the system has become very reliable with standardisations that provide significant cost benefits in repetitive operations.[292] Soyuz spacecraft used for crew rotation also serve as lifeboats for emergency evacuation; they are replaced every six months and were used after the Columbia disaster to return stranded crew from the ISS.[293] The average expedition requires 2,722 kg of supplies, and by 9 March 2011, crews had consumed a total of around 22,000 meals.[99] Soyuz crew rotation flights and Progress resupply flights visit the station on average two and three times respectively each year.[294] Other vehicles berth instead of docking. The Japanese H-II Transfer Vehicle parked itself in progressively closer orbits to the station, and then awaited 'approach' commands from the crew, until it was close enough for a robotic arm to grapple and berth the vehicle to the USOS. Berthed craft can transfer International Standard Payload Racks. Japanese spacecraft berth for one to two months.[295] The berthing Cygnus and SpaceX Dragon were contracted to fly cargo to the station under phase 1 of the Commercial Resupply Services program.[296][297] From 26 February 2011 to 7 March 2011 four of the governmental partners (United States, ESA, Japan and Russia) had their spacecraft (NASA Shuttle, ATV, HTV, Progress and Soyuz) docked at the ISS, the only time this has happened to date.[298] On 25 May 2012, SpaceX delivered the first commercial cargo with a Dragon spacecraft.[299] Launch and docking windows Prior to a spacecraft's docking to the ISS, navigation and attitude control (GNC) is handed over to the ground control of the spacecraft's country of origin. GNC is set to allow the station to drift in space, rather than fire its thrusters or turn using gyroscopes. The solar panels of the station are turned edge-on to the incoming spacecraft, so residue from its thrusters does not damage the cells. Before its retirement, Shuttle launches were often given priority over Soyuz, with occasional priority given to Soyuz arrivals carrying crew and time-critical cargoes, such as biological experiment materials.[300] Repairs Main article: Maintenance of the International Space Station Spare parts are called ORUs; some are externally stored on pallets called ELCs and ESPs. Two black and orange solar arrays, shown uneven and with a large tear visible. A crew member in a spacesuit, attached to the end of a robotic arm, holds a latticework between two solar sails. While anchored on the end of the OBSS during STS-120, astronaut Scott Parazynski performs makeshift repairs to a US solar array that damaged itself when unfolding. Mike Hopkins during a spacewalk Orbital Replacement Units (ORUs) are spare parts that can be readily replaced when a unit either passes its design life or fails. Examples of ORUs are pumps, storage tanks, controller boxes, antennas, and battery units. Some units can be replaced using robotic arms. Most are stored outside the station, either on small pallets called ExPRESS Logistics Carriers (ELCs) or share larger platforms called External Stowage Platforms which also hold science experiments. Both kinds of pallets provide electricity for many parts that could be damaged by the cold of space and require heating. The larger logistics carriers also have local area network (LAN) connections for telemetry to connect experiments. A heavy emphasis on stocking the USOS with ORU's occurred around 2011, before the end of the NASA shuttle programme, as its commercial replacements, Cygnus and Dragon, carry one tenth to one quarter the payload. Unexpected problems and failures have impacted the station's assembly time-line and work schedules leading to periods of reduced capabilities and, in some cases, could have forced abandonment of the station for safety reasons. Serious problems include an air leak from the USOS in 2004,[301] the venting of fumes from an Elektron oxygen generator in 2006,[302] and the failure of the computers in the ROS in 2007 during STS-117 that left the station without thruster, Elektron, Vozdukh and other environmental control system operations. In the latter case, the root cause was found to be condensation inside electrical connectors leading to a short circuit.[303] During STS-120 in 2007 and following the relocation of the P6 truss and solar arrays, it was noted during unfurling that the solar array had torn and was not deploying properly.[304] An EVA was carried out by Scott Parazynski, assisted by Douglas Wheelock. Extra precautions were taken to reduce the risk of electric shock, as the repairs were carried out with the solar array exposed to sunlight.[305] The issues with the array were followed in the same year by problems with the starboard Solar Alpha Rotary Joint (SARJ), which rotates the arrays on the starboard side of the station. Excessive vibration and high-current spikes in the array drive motor were noted, resulting in a decision to substantially curtail motion of the starboard SARJ until the cause was understood. Inspections during EVAs on STS-120 and STS-123 showed extensive contamination from metallic shavings and debris in the large drive gear and confirmed damage to the large metallic bearing surfaces, so the joint was locked to prevent further damage.[306][307] Repairs to the joints were carried out during STS-126 with lubrication and the replacement of 11 out of 12 trundle bearings on the joint.[308][309] In September 2008, damage to the S1 radiator was first noticed in Soyuz imagery. The problem was initially not thought to be serious.[310] The imagery showed that the surface of one sub-panel has peeled back from the underlying central structure, possibly because of micro-meteoroid or debris impact. On 15 May 2009 the damaged radiator panel's ammonia tubing was mechanically shut off from the rest of the cooling system by the computer-controlled closure of a valve. The same valve was then used to vent the ammonia from the damaged panel, eliminating the possibility of an ammonia leak.[310] It is also known that a Service Module thruster cover struck the S1 radiator after being jettisoned during an EVA in 2008, but its effect, if any, has not been determined. In the early hours of 1 August 2010, a failure in cooling Loop A (starboard side), one of two external cooling loops, left the station with only half of its normal cooling capacity and zero redundancy in some systems.[311][312][313] The problem appeared to be in the ammonia pump module that circulates the ammonia cooling fluid. Several subsystems, including two of the four CMGs, were shut down. Planned operations on the ISS were interrupted through a series of EVAs to address the cooling system issue. A first EVA on 7 August 2010, to replace the failed pump module, was not fully completed because of an ammonia leak in one of four quick-disconnects. A second EVA on 11 August successfully removed the failed pump module.[314][315] A third EVA was required to restore Loop A to normal functionality.[316][317] The USOS's cooling system is largely built by the US company Boeing,[318] which is also the manufacturer of the failed pump.[311] The four Main Bus Switching Units (MBSUs, located in the S0 truss), control the routing of power from the four solar array wings to the rest of the ISS. Each MBSU has two power channels that feed 160V DC from the arrays to two DC-to-DC power converters (DDCUs) that supply the 124V power used in the station. In late 2011 MBSU-1 ceased responding to commands or sending data confirming its health. While still routing power correctly, it was scheduled to be swapped out at the next available EVA. A spare MBSU was already on board, but a 30 August 2012 EVA failed to be completed when a bolt being tightened to finish installation of the spare unit jammed before the electrical connection was secured.[319] The loss of MBSU-1 limited the station to 75% of its normal power capacity, requiring minor limitations in normal operations until the problem could be addressed. On 5 September 2012, in a second six-hour EVA, astronauts Sunita Williams and Akihiko Hoshide successfully replaced MBSU-1 and restored the ISS to 100% power.[320] On 24 December 2013, astronauts installed a new ammonia pump for the station's cooling system. The faulty cooling system had failed earlier in the month, halting many of the station's science experiments. Astronauts had to brave a "mini blizzard" of ammonia while installing the new pump. It was only the second Christmas Eve spacewalk in NASA history.[321] Mission control centres Main article: International Space Station programme § Mission control centres The components of the ISS are operated and monitored by their respective space agencies at mission control centres across the globe, including RKA Mission Control Center, ATV Control Centre, JEM Control Center and HTV Control Center at Tsukuba Space Center, Christopher C. Kraft Jr. Mission Control Center, Payload Operations and Integration Center, Columbus Control Center and Mobile Servicing System Control. Life aboard Living quarters The living and working space on the International Space Station is larger than a six-bedroom house (complete with six sleeping quarters, two bathrooms, a gym, and a 360-degree view bay window).[322] Crew activities Engineer Gregory Chamitoff peering out of a window STS-122 mission specialists working on robotic equipment in the US lab A typical day for the crew begins with a wake-up at 06:00, followed by post-sleep activities and a morning inspection of the station. The crew then eats breakfast and takes part in a daily planning conference with Mission Control before starting work at around 08:10. The first scheduled exercise of the day follows, after which the crew continues work until 13:05. Following a one-hour lunch break, the afternoon consists of more exercise and work before the crew carries out its pre-sleep activities beginning at 19:30, including dinner and a crew conference. The scheduled sleep period begins at 21:30. In general, the crew works ten hours per day on a weekday, and five hours on Saturdays, with the rest of the time their own for relaxation or work catch-up.[323] The time zone used aboard the ISS is Coordinated Universal Time (UTC).[324] The windows are covered during night hours to give the impression of darkness because the station experiences 16 sunrises and sunsets per day. During visiting Space Shuttle missions, the ISS crew mostly followed the shuttle's Mission Elapsed Time (MET), which was a flexible time zone based on the launch time of the Space Shuttle mission.[325][326][327] The station provides crew quarters for each member of the expedition's crew, with two "sleep stations" in the Zvezda, one in Nauka and four more installed in Harmony.[328][329][330][331] The USOS quarters are private, approximately person-sized soundproof booths. The ROS crew quarters in Zvezda include a small window, but provide less ventilation and sound proofing. A crew member can sleep in a crew quarter in a tethered sleeping bag, listen to music, use a laptop, and store personal items in a large drawer or in nets attached to the module's walls. The module also provides a reading lamp, a shelf and a desktop.[332][333][334] Visiting crews have no allocated sleep module, and attach a sleeping bag to an available space on a wall. It is possible to sleep floating freely through the station, but this is generally avoided because of the possibility of bumping into sensitive equipment.[335] It is important that crew accommodations be well ventilated; otherwise, astronauts can wake up oxygen-deprived and gasping for air, because a bubble of their own exhaled carbon dioxide has formed around their heads.[332] During various station activities and crew rest times, the lights in the ISS can be dimmed, switched off, and colour temperatures adjusted.[336][337] Food and personal hygiene See also: Space food Nine astronauts seated around a table covered in open cans of food strapped down to the table. In the background a selection of equipment is visible, as well as the salmon-coloured walls of the Unity node. The crews of Expedition 20 and STS-127 enjoy a meal inside Unity. Main dining desk in Node 1 Fresh fruits and vegetables are grown in the ISS. On the USOS, most of the food aboard is vacuum sealed in plastic bags; cans are rare because they are heavy and expensive to transport. Preserved food is not highly regarded by the crew and taste is reduced in microgravity,[332] so efforts are taken to make the food more palatable, including using more spices than in regular cooking. The crew looks forward to the arrival of any spacecraft from Earth as they bring fresh fruit and vegetables. Care is taken that foods do not create crumbs, and liquid condiments are preferred over solid to avoid contaminating station equipment. Each crew member has individual food packages and cooks them using the on-board galley. The galley features two food warmers, a refrigerator (added in November 2008), and a water dispenser that provides both heated and unheated water.[333] Drinks are provided as dehydrated powder that is mixed with water before consumption.[333][334] Drinks and soups are sipped from plastic bags with straws, while solid food is eaten with a knife and fork attached to a tray with magnets to prevent them from floating away. Any food that floats away, including crumbs, must be collected to prevent it from clogging the station's air filters and other equipment.[334] Showers on space stations were introduced in the early 1970s on Skylab and Salyut 3.[338]: 139  By Salyut 6, in the early 1980s, the crew complained of the complexity of showering in space, which was a monthly activity.[339] The ISS does not feature a shower; instead, crewmembers wash using a water jet and wet wipes, with soap dispensed from a toothpaste tube-like container. Crews are also provided with rinseless shampoo and edible toothpaste to save water.[335][340] There are two space toilets on the ISS, both of Russian design, located in Zvezda and Tranquility.[333] These Waste and Hygiene Compartments use a fan-driven suction system similar to the Space Shuttle Waste Collection System. Astronauts first fasten themselves to the toilet seat, which is equipped with spring-loaded restraining bars to ensure a good seal.[332] A lever operates a powerful fan and a suction hole slides open: the air stream carries the waste away. Solid waste is collected in individual bags which are stored in an aluminium container. Full containers are transferred to Progress spacecraft for disposal.[333][341] Liquid waste is evacuated by a hose connected to the front of the toilet, with anatomically correct "urine funnel adapters" attached to the tube so that men and women can use the same toilet. The diverted urine is collected and transferred to the Water Recovery System, where it is recycled into drinking water.[334] In 2021, the arrival of the Nauka module also brought a third toilet to the ISS.[342] The space toilet in the Zvezda module in the Russian segment The main toilet in the US Segment inside the Tranquility module * Both toilets are of Russian design. Crew health and safety Main article: Effect of spaceflight on the human body Overall On 12 April 2019, NASA reported medical results from the Astronaut Twin Study. Astronaut Scott Kelly spent a year in space on the ISS, while his twin spent the year on Earth. Several long-lasting changes were observed, including those related to alterations in DNA and cognition, when one twin was compared with the other.[343][344] In November 2019, researchers reported that astronauts experienced serious blood flow and clot problems while on board the ISS, based on a six-month study of 11 healthy astronauts. The results may influence long-term spaceflight, including a mission to the planet Mars, according to the researchers.[345][346] Radiation See also: Coronal mass ejection 0:34 Video of the Aurora Australis, taken by the crew of Expedition 28 on an ascending pass from south of Madagascar to just north of Australia over the Indian Ocean The ISS is partially protected from the space environment by Earth's magnetic field. From an average distance of about 70,000 km (43,000 mi) from the Earth's surface, depending on Solar activity, the magnetosphere begins to deflect solar wind around Earth and the space station. Solar flares are still a hazard to the crew, who may receive only a few minutes warning. In 2005, during the initial "proton storm" of an X-3 class solar flare, the crew of Expedition 10 took shelter in a more heavily shielded part of the ROS designed for this purpose.[347][348] Subatomic charged particles, primarily protons from cosmic rays and solar wind, are normally absorbed by Earth's atmosphere. When they interact in sufficient quantity, their effect is visible to the naked eye in a phenomenon called an aurora. Outside Earth's atmosphere, ISS crews are exposed to approximately one millisievert each day (about a year's worth of natural exposure on Earth), resulting in a higher risk of cancer. Radiation can penetrate living tissue and damage the DNA and chromosomes of lymphocytes; being central to the immune system, any damage to these cells could contribute to the lower immunity experienced by astronauts. Radiation has also been linked to a higher incidence of cataracts in astronauts. Protective shielding and medications may lower the risks to an acceptable level.[59] Radiation levels on the ISS are between 12 and 28.8 milli rads per day,[349] about five times greater than those experienced by airline passengers and crew, as Earth's electromagnetic field provides almost the same level of protection against solar and other types of radiation in low Earth orbit as in the stratosphere. For example, on a 12-hour flight, an airline passenger would experience 0.1 millisieverts of radiation, or a rate of 0.2 millisieverts per day; this is only one fifth the rate experienced by an astronaut in LEO. Additionally, airline passengers experience this level of radiation for a few hours of flight, while the ISS crew are exposed for their whole stay on board the station.[350] Stress Cosmonaut Nikolai Budarin at work inside the Zvezda service module crew quarters There is considerable evidence that psychosocial stressors are among the most important impediments to optimal crew morale and performance.[351] Cosmonaut Valery Ryumin wrote in his journal during a particularly difficult period on board the Salyut 6 space station: "All the conditions necessary for murder are met if you shut two men in a cabin measuring 18 feet by 20 [5.5 m × 6 m] and leave them together for two months." NASA's interest in psychological stress caused by space travel, initially studied when their crewed missions began, was rekindled when astronauts joined cosmonauts on the Russian space station Mir. Common sources of stress in early US missions included maintaining high performance under public scrutiny and isolation from peers and family. The latter is still often a cause of stress on the ISS, such as when the mother of NASA astronaut Daniel Tani died in a car accident, and when Michael Fincke was forced to miss the birth of his second child. A study of the longest spaceflight concluded that the first three weeks are a critical period where attention is adversely affected because of the demand to adjust to the extreme change of environment.[352] ISS crew flights typically last about five to six months. The ISS working environment includes further stress caused by living and working in cramped conditions with people from very different cultures who speak a different language. First-generation space stations had crews who spoke a single language; second- and third-generation stations have crew from many cultures who speak many languages. Astronauts must speak English and Russian, and knowing additional languages is even better.[353] Due to the lack of gravity, confusion often occurs. Even though there is no up and down in space, some crew members feel like they are oriented upside down. They may also have difficulty measuring distances. This can cause problems like getting lost inside the space station, pulling switches in the wrong direction or misjudging the speed of an approaching vehicle during docking.[354] Medical A man running on a treadmill, smiling at the camera, with bungee cords stretching down from his waistband to the sides of the treadmill Astronaut Frank De Winne, attached to the TVIS treadmill with bungee cords aboard the ISS The physiological effects of long-term weightlessness include muscle atrophy, deterioration of the skeleton (osteopenia), fluid redistribution, a slowing of the cardiovascular system, decreased production of red blood cells, balance disorders, and a weakening of the immune system. Lesser symptoms include loss of body mass, and puffiness of the face.[59] Sleep is regularly disturbed on the ISS because of mission demands, such as incoming or departing spacecraft. Sound levels in the station are unavoidably high. The atmosphere is unable to thermosiphon naturally, so fans are required at all times to process the air which would stagnate in the freefall (zero-G) environment. To prevent some of the adverse effects on the body, the station is equipped with: two TVIS treadmills (including the COLBERT); the ARED (Advanced Resistive Exercise Device), which enables various weightlifting exercises that add muscle without raising (or compensating for) the astronauts' reduced bone density;[355] and a stationary bicycle. Each astronaut spends at least two hours per day exercising on the equipment.[332][333] Astronauts use bungee cords to strap themselves to the treadmill.[356][357] Microbiological environmental hazards See also: Microbiological environmental hazards on the Mir space station Hazardous molds that can foul air and water filters may develop aboard space stations. They can produce acids that degrade metal, glass, and rubber. They can also be harmful to the crew's health. Microbiological hazards have led to a development of the LOCAD-PTS which identifies common bacteria and molds faster than standard methods of culturing, which may require a sample to be sent back to Earth.[358] Researchers in 2018 reported, after detecting the presence of five Enterobacter bugandensis bacterial strains on the ISS (none of which are pathogenic to humans), that microorganisms on the ISS should be carefully monitored to continue assuring a medically healthy environment for astronauts.[359][360] Contamination on space stations can be prevented by reduced humidity, and by using paint that contains mold-killing chemicals, as well as the use of antiseptic solutions. All materials used in the ISS are tested for resistance against fungi.[361] In April 2019, NASA reported that a comprehensive study had been conducted into the microorganisms and fungi present on the ISS. The results may be useful in improving the health and safety conditions for astronauts.[362][363] Noise Space flight is not inherently quiet, with noise levels exceeding acoustic standards as far back as the Apollo missions.[364][365] For this reason, NASA and the International Space Station international partners have developed noise control and hearing loss prevention goals as part of the health program for crew members. Specifically, these goals have been the primary focus of the ISS Multilateral Medical Operations Panel (MMOP) Acoustics Subgroup since the first days of ISS assembly and operations.[366][367] The effort includes contributions from acoustical engineers, audiologists, industrial hygienists, and physicians who comprise the subgroup's membership from NASA, Roscosmos, the European Space Agency (ESA), the Japanese Aerospace Exploration Agency (JAXA), and the Canadian Space Agency (CSA). When compared to terrestrial environments, the noise levels incurred by astronauts and cosmonauts on the ISS may seem insignificant and typically occur at levels that would not be of major concern to the Occupational Safety and Health Administration – rarely reaching 85 dBA. But crew members are exposed to these levels 24 hours a day, seven days a week, with current missions averaging six months in duration. These levels of noise also impose risks to crew health and performance in the form of sleep interference and communication, as well as reduced alarm audibility. Over the 19 plus year history of the ISS, significant efforts have been put forth to limit and reduce noise levels on the ISS. During design and pre-flight activities, members of the Acoustic Subgroup have written acoustic limits and verification requirements, consulted to design and choose quietest available payloads, and then conducted acoustic verification tests prior to launch.[366]: 5.7.3  During spaceflights, the Acoustics Subgroup has assessed each ISS module's in flight sound levels, produced by a large number of vehicle and science experiment noise sources, to assure compliance with strict acoustic standards. The acoustic environment on ISS changed when additional modules were added during its construction, and as additional spacecraft arrive at the ISS. The Acoustics Subgroup has responded to this dynamic operations schedule by successfully designing and employing acoustic covers, absorptive materials, noise barriers, and vibration isolators to reduce noise levels. Moreover, when pumps, fans, and ventilation systems age and show increased noise levels, this Acoustics Subgroup has guided ISS managers to replace the older, noisier instruments with quiet fan and pump technologies, significantly reducing ambient noise levels. NASA has adopted most-conservative damage risk criteria (based on recommendations from the National Institute for Occupational Safety and Health and the World Health Organization), in order to protect all crew members. The MMOP Acoustics Subgroup has adjusted its approach to managing noise risks in this unique environment by applying, or modifying, terrestrial approaches for hearing loss prevention to set these conservative limits. One innovative approach has been NASA's Noise Exposure Estimation Tool (NEET), in which noise exposures are calculated in a task-based approach to determine the need for hearing protection devices (HPDs). Guidance for use of HPDs, either mandatory use or recommended, is then documented in the Noise Hazard Inventory, and posted for crew reference during their missions. The Acoustics Subgroup also tracks spacecraft noise exceedances, applies engineering controls, and recommends hearing protective devices to reduce crew noise exposures. Finally, hearing thresholds are monitored on-orbit, during missions. There have been no persistent mission-related hearing threshold shifts among US Orbital Segment crewmembers (JAXA, CSA, ESA, NASA) during what is approaching 20 years of ISS mission operations, or nearly 175,000 work hours. In 2020, the MMOP Acoustics Subgroup received the Safe-In-Sound Award for Innovation for their combined efforts to mitigate any health effects of noise.[368] Fire and toxic gases An onboard fire or a toxic gas leak are other potential hazards. Ammonia is used in the external radiators of the station and could potentially leak into the pressurised modules.[369] Orbit Altitude and orbital inclination Graph showing the changing altitude of the ISS from November 1998 until November 2018 Animation of ISS orbit from 14 September 2018 to 14 November 2018. Earth is not shown. The ISS is currently maintained in a nearly circular orbit with a minimum mean altitude of 370 km (230 mi) and a maximum of 460 km (290 mi),[370] in the centre of the thermosphere, at an inclination of 51.6 degrees to Earth's equator with an eccentricity of 0.007. This orbit was selected because it is the lowest inclination that can be directly reached by Russian Soyuz and Progress spacecraft launched from Baikonur Cosmodrome at 46° N latitude without overflying China or dropping spent rocket stages in inhabited areas.[371][372] It travels at an average speed of 28,000 kilometres per hour (17,000 mph), and completes 15.5 orbits per day (93 minutes per orbit).[3][19] The station's altitude was allowed to fall around the time of each NASA shuttle flight to permit heavier loads to be transferred to the station. After the retirement of the shuttle, the nominal orbit of the space station was raised in altitude (from about 350 km to about 400 km).[373][374] Other, more frequent supply spacecraft do not require this adjustment as they are substantially higher performance vehicles.[44][375] Atmospheric drag reduces the altitude by about 2 km a month on average. Orbital boosting can be performed by the station's two main engines on the Zvezda service module, or Russian or European spacecraft docked to Zvezda's aft port. The Automated Transfer Vehicle is constructed with the possibility of adding a second docking port to its aft end, allowing other craft to dock and boost the station. It takes approximately two orbits (three hours) for the boost to a higher altitude to be completed.[375] Maintaining ISS altitude uses about 7.5 tonnes of chemical fuel per annum[376] at an annual cost of about $210 million.[377] Orbits of the ISS, shown in April 2013 The Russian Orbital Segment contains the Data Management System, which handles Guidance, Navigation and Control (ROS GNC) for the entire station.[378] Initially, Zarya, the first module of the station, controlled the station until a short time after the Russian service module Zvezda docked and was transferred control. Zvezda contains the ESA built DMS-R Data Management System.[379] Using two fault-tolerant computers (FTC), Zvezda computes the station's position and orbital trajectory using redundant Earth horizon sensors, Solar horizon sensors as well as Sun and star trackers. The FTCs each contain three identical processing units working in parallel and provide advanced fault-masking by majority voting. Orientation Zvezda uses gyroscopes (reaction wheels) and thrusters to turn itself around. Gyroscopes do not require propellant; instead they use electricity to 'store' momentum in flywheels by turning in the opposite direction to the station's movement. The USOS has its own computer-controlled gyroscopes to handle its extra mass. When gyroscopes 'saturate', thrusters are used to cancel out the stored momentum. In February 2005, during Expedition 10, an incorrect command was sent to the station's computer, using about 14 kilograms of propellant before the fault was noticed and fixed. When attitude control computers in the ROS and USOS fail to communicate properly, this can result in a rare 'force fight' where the ROS GNC computer must ignore the USOS counterpart, which itself has no thrusters.[380][381][382] Docked spacecraft can also be used to maintain station attitude, such as for troubleshooting or during the installation of the S3/S4 truss, which provides electrical power and data interfaces for the station's electronics.[383] Orbital debris threats Main article: Space debris The low altitudes at which the ISS orbits are also home to a variety of space debris,[384] including spent rocket stages, defunct satellites, explosion fragments (including materials from anti-satellite weapon tests), paint flakes, slag from solid rocket motors, and coolant released by US-A nuclear-powered satellites. These objects, in addition to natural micrometeoroids,[385] are a significant threat. Objects large enough to destroy the station can be tracked, and are not as dangerous as smaller debris.[386][387] Objects too small to be detected by optical and radar instruments, from approximately 1 cm down to microscopic size, number in the trillions. Despite their small size, some of these objects are a threat because of their kinetic energy and direction in relation to the station. Spacewalking crew in spacesuits are also at risk of suit damage and consequent exposure to vacuum.[388] Ballistic panels, also called micrometeorite shielding, are incorporated into the station to protect pressurised sections and critical systems. The type and thickness of these panels depend on their predicted exposure to damage. The station's shields and structure have different designs on the ROS and the USOS. On the USOS, Whipple Shields are used. The US segment modules consist of an inner layer made from 1.5–5.0 cm-thick (0.59–1.97 in) aluminium, a 10 cm-thick (3.9 in) intermediate layers of Kevlar and Nextel (a ceramic fabric),[389] and an outer layer of stainless steel, which causes objects to shatter into a cloud before hitting the hull, thereby spreading the energy of impact. On the ROS, a carbon fibre reinforced polymer honeycomb screen is spaced from the hull, an aluminium honeycomb screen is spaced from that, with a screen-vacuum thermal insulation covering, and glass cloth over the top.[390] Space debris is tracked remotely from the ground, and the station crew can be notified.[391] If necessary, thrusters on the Russian Orbital Segment can alter the station's orbital altitude, avoiding the debris. These Debris Avoidance Manoeuvres (DAMs) are not uncommon, taking place if computational models show the debris will approach within a certain threat distance. Ten DAMs had been performed by the end of 2009.[392][393][394] Usually, an increase in orbital velocity of the order of 1 m/s is used to raise the orbit by one or two kilometres. If necessary, the altitude can also be lowered, although such a manoeuvre wastes propellant.[393][395] If a threat from orbital debris is identified too late for a DAM to be safely conducted, the station crew close all the hatches aboard the station and retreat into their spacecraft in order to be able to evacuate in the event the station was seriously damaged by the debris. This partial station evacuation has occurred on 13 March 2009, 28 June 2011, 24 March 2012 and 16 June 2015.[396][397] In November 2021, a debris cloud from the destruction of Kosmos 1408 by an anti-satellite weapons test threatened the ISS, leading to the announcement of a yellow alert, leading to crew sheltering in the crew capsules.[398] A couple of weeks later, it had to perform an unscheduled maneuver to drop the station by 310 meters to avoid a collision with hazardous space debris.[399]     A 7-gram object (shown in centre) shot at 7 km/s (23,000 ft/s), the orbital velocity of the ISS, made this 15 cm (5.9 in) crater in a solid block of aluminium.     A 7-gram object (shown in centre) shot at 7 km/s (23,000 ft/s), the orbital velocity of the ISS, made this 15 cm (5.9 in) crater in a solid block of aluminium.     Radar-trackable objects, including debris, with distinct ring of geostationary satellites     Radar-trackable objects, including debris, with distinct ring of geostationary satellites     Example of risk management: A NASA model showing areas at high risk from impact for the International Space Station.     Example of risk management: A NASA model showing areas at high risk from impact for the International Space Station.     A blueprint of a typical debris "Whipple Shield" design     A blueprint of a typical debris "Whipple Shield" design Sightings from Earth Further information: Satellite watching and Satellite flare The ISS is visible to the naked eye as a slow-moving, bright white dot because of reflected sunlight, and can be seen in the hours after sunset and before sunrise, when the station remains sunlit but the ground and sky are dark.[400] The ISS takes about 10 minutes to pass from one horizon to another, and will only be visible part of that time because of moving into or out of the Earth's shadow. Because of the size of its reflective surface area, the ISS is the brightest artificial object in the sky (excluding other satellite flares), with an approximate maximum magnitude of −4 when in sunlight and overhead (similar to Venus), and a maximum angular size of 63 arcseconds.[401] The ISS, like many satellites including the Iridium constellation, can also produce flares of up to 16 times the brightness of Venus as sunlight glints off reflective surfaces.[402][403] The ISS is also visible in broad daylight, albeit with a great deal more difficulty. Tools are provided by a number of websites such as Heavens-Above (see Live viewing below) as well as smartphone applications that use orbital data and the observer's longitude and latitude to indicate when the ISS will be visible (weather permitting), where the station will appear to rise, the altitude above the horizon it will reach and the duration of the pass before the station disappears either by setting below the horizon or entering into Earth's shadow.[404][405][406][407] In November 2012 NASA launched its "Spot the Station" service, which sends people text and email alerts when the station is due to fly above their town.[408] The station is visible from 95% of the inhabited land on Earth, but is not visible from extreme northern or southern latitudes.[371] Under specific conditions, the ISS can be observed at night on five consecutive orbits. Those conditions are 1) a mid-latitude observer location, 2) near the time of the solstice with 3) the ISS passing in the direction of the pole from the observer near midnight local time. The three photos show the first, middle and last of the five passes on 5–6 June 2014.     Skytrack long duration exposure of the ISS     Skytrack long duration exposure of the ISS     The ISS on its first pass of the night passing nearly overhead shortly after sunset in June 2014     The ISS on its first pass of the night passing nearly overhead shortly after sunset in June 2014     The ISS passing north on its third pass of the night near local midnight in June 2014     The ISS passing north on its third pass of the night near local midnight in June 2014     The ISS passing west on its fifth pass of the night before sunrise in June 2014     The ISS passing west on its fifth pass of the night before sunrise in June 2014 Astrophotography The ISS and HTV photographed from Earth by Ralf Vandebergh Using a telescope-mounted camera to photograph the station is a popular hobby for astronomers,[409] while using a mounted camera to photograph the Earth and stars is a popular hobby for crew.[410] The use of a telescope or binoculars allows viewing of the ISS during daylight hours.[411] Composite of six photos of the ISS transiting the gibbous Moon Transits of the ISS in front of the Sun, particularly during an eclipse (and so the Earth, Sun, Moon, and ISS are all positioned approximately in a single line) are of particular interest for amateur astronomers.[412][413] International co-operation Main articles: Politics of the International Space Station and International Space Station programme A Commemorative Plaque honouring Space Station Intergovernmental Agreement signed on 28 January 1998 Involving five space programs and fifteen countries,[414] the International Space Station is the most politically and legally complex space exploration programme in history.[415] The 1998 Space Station Intergovernmental Agreement sets forth the primary framework for international cooperation among the parties. A series of subsequent agreements govern other aspects of the station, ranging from jurisdictional issues to a code of conduct among visiting astronauts.[416] Following the 2022 Russian invasion of Ukraine, continued cooperation between Russia and other countries on the International Space Station has been put into question. British Prime Minister Boris Johnson commented on the current status of cooperation, saying "I have been broadly in favour of continuing artistic and scientific collaboration, but in the current circumstances it's hard to see how even those can continue as normal."[417] On the same day, Roscosmos Director General Dmitry Rogozin insinuated that Russian withdrawal could cause the International Space Station to de-orbit due to lack of reboost capabilities, writing in a series of tweets, "If you block cooperation with us, who will save the ISS from an unguided de-orbit to impact on the territory of the US or Europe? There's also the chance of impact of the 500-ton construction in India or China. Do you want to threaten them with such a prospect? The ISS doesn't fly over Russia, so all the risk is yours. Are you ready for it?"[418] Rogozin later tweeted that normal relations between ISS partners could only be restored once sanctions have been lifted, and indicated that Roscosmos would submit proposals to the Russian government on ending cooperation.[419] NASA stated that, if necessary, US corporation Northrop Grumman has offered a reboost capability that would keep the ISS in orbit.[420] On 26 July 2022, Yury Borisov, Rogozin's successor as head of Roscosmos, submitted to Russian President Putin plans for withdrawal from the programme after 2024.[20] However, Robyn Gatens, the NASA official in charge of the space station, responded that NASA had not received any formal notices from Roscosmos concerning withdrawal plans.[21] Participating countries      Brazil (1997–2007)      Canada     European Space Agency          Belgium          Denmark          France          Germany          Italy          Netherlands          Norway          Spain          Sweden          Switzerland          United Kingdom      Japan      Russia      United States End of mission Many ISS resupply spacecraft have already undergone atmospheric re-entry, such as Jules Verne ATV. According to the Outer Space Treaty, the United States and Russia are legally responsible for all modules they have launched.[421] Several possible disposal options were considered: Natural orbital decay with random reentry (as with Skylab), boosting the station to a higher altitude (which would delay reentry), and a controlled targeted de-orbit to a remote ocean area.[422] In late 2010, the preferred plan was to use a slightly modified Progress spacecraft to de-orbit the ISS.[423] This plan was seen as the simplest, cheapest and with the highest margin of safety.[clarify][423] OPSEK was previously intended to be constructed of modules from the Russian Orbital Segment after the ISS is decommissioned. The modules under consideration for removal from the current ISS included the Multipurpose Laboratory Module (Nauka), launched in July 2021, and the other new Russian modules that are proposed to be attached to Nauka. These newly launched modules would still be well within their useful lives in 2024.[424] At the end of 2011, the Exploration Gateway Platform concept also proposed using leftover USOS hardware and Zvezda 2 as a refuelling depot and service station located at one of the Earth–Moon Lagrange points. However, the entire USOS was not designed for disassembly and will be discarded.[425] On 30 September 2015, Boeing's contract with NASA as prime contractor for the ISS was extended to 30 September 2020. Part of Boeing's services under the contract related to extending the station's primary structural hardware past 2020 to the end of 2028.[426] There have also been suggestions in the commercial space industry that the station could be converted to commercial operations after it is retired by government entities.[427] In July 2018, the Space Frontier Act of 2018 was intended to extend operations of the ISS to 2030. This bill was unanimously approved in the Senate, but failed to pass in the U.S. House.[428][429] In September 2018, the Leading Human Spaceflight Act was introduced with the intent to extend operations of the ISS to 2030, and was confirmed in December 2018.[27][28][430] Congress later passed similar provisions in its CHIPS and Science Act, signed into law by President Joe Biden on 9 August 2022.[431][432] In January 2022, NASA announced a planned date of January 2031 to de-orbit the ISS using a deorbit module and direct any remnants into a remote area of the South Pacific Ocean.[433] Cost The ISS has been described as the most expensive single item ever constructed.[434] As of 2010, the total cost was US$150 billion. This includes NASA's budget of $58.7 billion ($89.73 billion in 2021 dollars) for the station from 1985 to 2015, Russia's $12 billion, Europe's $5 billion, Japan's $5 billion, Canada's $2 billion, and the cost of 36 shuttle flights to build the station, estimated at $1.4 billion each, or $50.4 billion in total. Assuming 20,000 person-days of use from 2000 to 2015 by two- to six-person crews, each person-day would cost $7.5 million, less than half the inflation-adjusted $19.6 million ($5.5 million before inflation) per person-day of Skylab.[435] In film Beside numerous documentaries such as the IMAX documentaries Space Station 3D from 2002,[436] or A Beautiful Planet from 2016,[437] the ISS is the subject of feature films such as The Day After Tomorrow (2004),[438] Life (2017),[439] Love (2011),[440] or – together with the Chinese station Tiangong space station – in Gravity (2013).[441] In 2022, the movie The Challenge (Russian: Вызов) was filmed aboard the ISS, and was notable for being the first feature film in which both professional actors and director worked together in space." (wikipedia.org) "Science, technology, engineering, and mathematics (STEM) is an umbrella term used to group together the distinct but related technical disciplines of science, technology, engineering, and mathematics. The term is typically used in the context of education policy or curriculum choices in schools. It has implications for workforce development, national security concerns (as a shortage of STEM-educated citizens can reduce effectiveness in this area) and immigration policy, with regards to admitting foreign students and tech workers.[1] There is no universal agreement on which disciplines are included in STEM; in particular whether or not the science in STEM includes social sciences, such as psychology, sociology, economics, and political science. In the United States, these are typically included by organizations such as the National Science Foundation (NSF),[1] the Department of Labor's O*Net online database for job seekers,[2] and the Department of Homeland Security.[3] In the United Kingdom, the social sciences are categorized separately and are instead grouped together with humanities and arts to form another counterpart acronym HASS (Humanities, Arts, and Social Sciences), rebranded in 2020 as SHAPE (Social Sciences, Humanities and the Arts for People and the Economy).[4][5] Some sources also use HEAL (health, education, administration, and literacy) as the counterpart of STEM.[6] Terminology History In the early 1990s, the acronym STEM was used by a variety of educators in preference to SMET, including Charles E. Vela, the founder and director of the Center for the Advancement of Hispanics in Science and Engineering Education (CAHSEE).[7][8][9] Moreover, the CAHSEE started a summer program for talented under-represented students in the Washington, D.C., area called the STEM Institute. Based on the program's recognized success and his expertise in STEM education,[10] Charles Vela was asked to serve on numerous NSF and Congressional panels in science, mathematics and engineering education;[11] it is through this manner that NSF was first introduced to the acronym STEM. One of the first NSF projects to use the acronym was STEMTEC, the Science, Technology, Engineering and Math Teacher Education Collaborative at the University of Massachusetts Amherst, which was founded in 1998.[12] In 2001, at the urging of Dr. Peter Faletra, the Director of Workforce Development for Teachers and Scientists at the Office of Science, the acronym was adopted by Rita Colwell and other science administrators in the National Science Foundation (NSF). The Office of Science was also an early adopter of the STEM acronym.[13] Other variations A-STEM (arts, science, technology, engineering, and mathematics);[14] more focus and based on humanism and arts. eSTEM (environmental STEM)[15][16] GEMS (girls in engineering, math, and science); used for programs to encourage women to enter these fields.[17][18] MINT (mathematics, informatics, natural sciences, and technology)[19] SHTEAM (science, humanities, technology, engineering, arts, and mathematics)[20] SMET (science, mathematics, engineering, and technology); previous name[21] STEAM (science, technology, engineering, arts, and mathematics)[22]     STEAM (science, technology, engineering, agriculture, and mathematics); add agriculture[23]     STEAM (science, technology, engineering, and applied mathematics); more focus on applied mathematics[24] STEEM (science, technology, engineering, economics, and mathematics); adds economics as a field[25] STEMIE (science, technology, engineering, mathematics, invention and entrepreneurship); adds Inventing and Entrepreneurship as means to apply STEM to real world problem solving and markets.[26] STEMM (science, technology, engineering, mathematics, and medicine)[27] STM (scientific, technical, and mathematics[28] or science, technology, and medicine)[29] STREAM (science, technology, robotics, engineering, arts, and mathematics); adds robotics and arts as fields[" (wikipedia.org) "Lenticular printing is a technology in which lenticular lenses (a technology also used for 3D displays) are used to produce printed images with an illusion of depth, or the ability to change or move as they are viewed from different angles. Examples include flip and animation effects such as winking eyes, and modern advertising graphics whose messages change depending on the viewing angle. Colloquial terms for lenticular prints include "flickers", "winkies", "wiggle pictures", and "tilt cards". The trademarks Vari-Vue and Magic Motion are often used for lenticular pictures, without regard to the actual manufacturer. Process How a lenticular lens works Lenticular printing is a multi-step process which consists of creating a lenticular image from at least two images, and placing it behind a lenticular lens. It can be used to create frames of animation, for a motion effect; offsetting the various layers at different increments, for a 3D effect; or simply to show sets of alternative images that appear to transform into each other. Once the images are collected, they are arranged in individual frame files, then digitally combined into a single file in a process called interlacing. The interlaced image may be printed directly on the back (smooth side) of the lens, or on a substrate (ideally a synthetic paper) which is laminated to the lens. When printing on the backside of the lens, the critical registration of the fine "slices" of interlaced images must be absolutely correct during the lithographic or screen printing process to avoid "ghosting" and poor image definition. The combined lenticular print shows two or more images by changing the angle from which the print is viewed. If a sequence of images is used, it can even show a short animation. Though normally produced in sheet form by interlacing simple images or colors throughout the artwork, lenticular images can also be created in roll form with 3D effects or multi-color changes. Alternatively, several images of the same object, taken from slightly different angles, can be used to create a lenticular print with a stereoscopic 3D effect. 3D effects can be achieved only in a lateral (side-by-side) orientation, as each of the viewer's eyes must see them from a slightly different angle to achieve the stereoscopic effect. Other effects, like morphs, motion, and zooms work better (with less ghosting or latent effects) in top-to-bottom orientation, but can be achieved in both orientations. There are many commercial processes in the manufacture of lenticular images, which can be made from PVC, APET, acrylic, and PETG, as well as other materials. While PETG and APET are the most common, other materials are becoming popular to accommodate outdoor use and special forming due to the increasing use of lenticular images on items such as gift cards. Lithographic lenticular printing allows for the flat side of the lenticular sheet to have ink placed directly onto the lens, while high-resolution photographic lenticulars typically have the image laminated to the lens.[citation needed] Lenticular images saw a surge in popularity in the first decade of the 21st century, appearing on the cover of the May 2006 issue of Rolling Stone, trading cards, sports posters, and signs in stores that help to attract buyers.[citation needed] Construction Images are interlaced on the substrate Each image is arranged (slicing) into strips, which are then interlaced with one or more similarly arranged images (splicing). These are printed on the back of a piece of plastic, with a series of thin lenses molded into the opposite side. Alternatively, the images can be printed on paper, which is then bonded to the plastic. With the new technology, lenses are printed in the same printing operation as the interlaced image, either on both sides of a flat sheet of transparent material, or on the same side of a sheet of paper, the image being covered with a transparent sheet of plastic or with a layer of transparent, which in turn is printed with several layers of varnish to create the lenses. The lenses are accurately aligned with the interlaces of the image, so that light reflected off each strip is refracted in a slightly different direction, but the light from all pixels originating from the same original image is sent in the same direction. The end result is that a single eye looking at the print sees a single whole image, but two eyes will see different images, which leads to stereoscopic 3D perception. Types of lenticular prints There are three distinct types of lenticular prints, distinguished by how great a change in angle of view is required to change the image: Transforming prints     Here two or more very different pictures are used, and the lenses are designed to require a relatively large change in angle of view to switch from one image to another. This allows viewers to easily see the original images, since small movements cause no change. Larger movement of the viewer or the print causes the image to flip from one image to another (the "flip effect"). An example of this is the lenticular print of hockey player Mario Tremblay at Centre Mario-Tremblay in Alma, Quebec where he is transformed from a minor hockey playing boy as an Alma Eagle into the professional hockey playing man, four years later, as a Montreal Canadien.[1] Animated prints     Here the distance between different angles of view is "medium", so that while both eyes usually see the same picture, moving a little bit switches to the next picture in the series. Two or more sequential images are used, with only small differences between each image and the next. This can be used to create an image that moves ("motion effect"), or can create a "zoom" or "morph" effect, in which part of the image expands in size or changes shape as the angle of view changes. The movie poster of the film Species II, shown in this article, is an example of this technique. Stereoscopic effects     Here the change in viewing angle needed to change images is small, so that each eye sees a slightly different view. This creates a 3D effect without requiring special glasses, using two or more images. For example, the Dolby-Philips Lenticular 3D display produces 28 different images. Motorized lenticular With static (non-motorized) lenticular, the viewer either moves the piece or moves past the piece in order to see the graphic effects. With motorized lenticular, a motor moves the graphics behind the lens, enabling the graphic effects while both the viewer and the display remain stationary. History Predecessors Tabula scalata Main article: Tabula scalata Corrugated images that change when viewed from different angles predate the development of lenticular printing. A few examples from the paleolithic era exist in French caves.[2][3] Tabula scalata or "turning pictures" were popular in England since the 16th century.[4] Extant double paintings, with two distinct images on a corrugated panel, are known from the 17th century.[5][6] H.C.J. Deeks used a similar technique with minute vertical corrugations pressed into photographic paper and then exposed to two different images from two different angles.[7] Under a 1906 patent H.C.J. Deeks & Co marketed a Puzzle Post Card or Photochange Post Card. In 1907 a Colorchange Post Card followed, featuring identical pictures on each side of the corrugations that were sprayed with different "liquid pigment or coloring matter" on (parts of) each side.[8] Barrier grid autostereograms and animation Main article: Barrier grid animation and stereography Berthier's diagram: A-B=glass plate, with a-b=opaque lines, P=Picture, O=Eyes, c-n=blocked and allowed views (Le Cosmos 05-1896) The oldest known publication about using a line sheet as a parallax barrier to produce an autostereogram is found in an article by Auguste Berthier in the French scientific magazine "Le Cosmos" of May 1896.[9] Berthier's idea was hardly noticed, but American inventor Frederic Eugene Ives had more success with his very similar parallax stereogram since 1901. He also patented the technique for a "Changeable sign, picture, &c." in 1903, which showed different pictures from different angles (instead of one stereoscopic image from the right angle and distance). Léon Gaumont introduced Ives' pictures in France and encouraged Eugène Estanave to work on the technique. Estanave patented a barrier grid technique for animated autostereograms. Animated portrait photographs with line sheets were marketed for a while, mostly in the 1910s and 1920s. In the US "Magic Moving Picture" postcards with simple 3 phase animation or changing pictures were marketed after 1906. Maurice Bonnett improved barrier grid autostereography in the 1930s with his relièphographie technique and scanning cameras. On 11 April 1898 John Jacobson filed an application for US patent No. 624,043 (granted 2 May 1899) for a Stereograph of an interlaced stereoscopic picture and "a transparent mount for said picture having a corrugated or channeled surface".[10] The corrugated lines or channels were not yet really lenticular, but this is the first known autostereogram that used a corrugated transparent surface rather than the opaque lines of most barrier grid stereograms. Gabriel Lippmann's integral photography Main article: Integral imaging French Nobel Prize winning physicist Gabriel Lippmann represented Eugène Estanave at several presentations of Estanave's works at the French Academy of Sciences. On 2 March 1908 Lippmann presented his own ideas for "photographie intégrale", based on insect eyes. He suggested to use a screen of tiny lenses. Spherical segments should be pressed into a sort of film with photographic emulsion on the other side. The screen would be placed inside a lightproof holder and on a tripod for stability. When exposed each tiny lens would function as a camera and record the surroundings from a slightly different angle than neighboring lenses. When developed and lit from behind the lenses should project the life-size image of the recorded subject in space. He could not yet present concrete results in March 1908, but by the end of 1908 he claimed to have exposed some Integral photography plates and to have seen the "resulting single, full-sized image". However, the technique remained experimental since no material or technique seemed to deliver the optical quality desired. At the time of his death in 1921 Lippmann reportedly had a system with only twelve lenses.[11] Early lenticular methods On 11 April 1898, John Jacobson filed an application for US patent No. 624,043 (granted 2 May 1899) for a Stereograph of an interlaced stereoscopic picture and "a transparent mount for said picture having a corrugated or channeled surface".[10] In 1912, Louis Chéron described in his French patent 443,216 a screen with long vertical lenses that would be sufficient for recording "stereoscopic depth and the shifting of the relations of objects to each other as the viewer moved", while he suggested pinholes for integral photography.[11] In June 1912, Swiss Nobel Prize winning physiologist Walter Rudolf Hess applied for a US patent for a Stereoscopic picture with a "celluloid covering having a surface composed of cylindrical lens elements".[12] US patent 1,128,979 (published 16 February 1915) was one of several patents in different countries he would register for this technique. The company Stereo-Photographie A.G., registered in Zürich in 1914 and 1915, would produce pictures on transparencies through Hess' process. Few examples of these pictures are still known to have survived. They are circa 3 1/6 × 4 inches black and white pictures (with discolored or intentional hues) and labeled on their passe-partouts "Stereo-Photo nach W.R. Hess - Stereo-Photographie A.G. Zürich. Patente: "Schweiz / Deutschland / Frankreich / Italien / England / Oesterreich / Vereinigte Staaten angemeldet". The Société française de photographie has three lenticular "Stereo-photo" plates in their collection, three more were on auction in 2017.[13][11][14] Herbert E. Ives, son of Frederic Eugene Ives, was one of several researchers who worked on lenticular sheets in the 1920s. These were basically simpler versions of Lippmann's integral photography and had a linear array of small plano-convex cylindrical lenses (lenticules).[15] The first successful commercial application of the lenticular technique was not used for 3D or motion display but for color movies. Eastman Kodak's 1928 Kodacolor film was based on Keller-Dorian cinematography. It used 16 mm black and white sensitive film embossed with 600 lenses per square inch for use with a filter with RGB stripes.[16] In the 1930s several US patents relating to lenticular techniques were granted, mostly for color film.[17] On 15 December 1936, Douglas F. Winnek Coffey was granted US patent 2,063,985 (application 24 May 1935) for an "Apparatus for making a composite stereograph".[18] The description does not include changing pictures or animation concepts. Further history During World War II, research for military purposes was done into 3D imaging, including lenticular technologies. Mass production of plastics and the technique of injection moulding came about around the same period and enabled commercially viable production of lenticular sheets for novelty toys and advertisements.[19] Victor Anderson and Vari-Vue Victor G. Anderson worked for the Sperry Corporation during World War II where 3D imaging was used for military instructional products, for instance on how to use a bomb sight. After the war Anderson started his company Pictorial Productions Inc. A patent application for a Process in the assembling of changeable picture display devices was filed on 1 March 1952 and granted on 3 December 1957 (US patent 2,815,310. Anderson stated in 1996 that the company's first product was the I Like Ike button.[19] The presidential campaign button's image changed from the slogan "I Like Ike" (in black letters on white) into a black and white picture of Ike Eisenhower when viewed from different angles.[20] It was copyrighted on 14 May 1952.[21] In December 1953 the company registered their trademark Vari-Vue.[22] Vari-Vue further popularized lenticular images during the 1950s and 1960s. By the late sixties, the company marketed about two thousand stock products including twelve-inch-square (30 cm) moving pattern and color sheets, large images (many religious), billboards, and novelty toys.[citation needed] The company went bankrupt in 1986.[23] Xograph Look magazine of 25 February 1964 introduced the publisher's "parallax panoramagram" technology with 8 million copies of a 10x12 cm black and white card with a photographic 3D image of an Edison bust surrounded by some inventions. A 10 x 12 cm full color picture of a model promoting Kodel followed on 7 April. The technique was soon trademarked as "xograph" by Cowles' daughter company Visual Panographics Inc. Magazines like Look and Venture published xographs until the mid 1970s. Some baseball cards were produced as xographs.[24][25] Images produced by the company ranged from just a few millimeters (0.1 inch) to 28 by 19.5 inches (71 by 50 cm).[citation needed] Other early companies In the 1960s, more companies manufactured lenticular products, including Hallmark Cards (registering the Magic Motion trademark in 1964[26]), Reflexa (Nürnberg, Germany), Toppan (Tokyo, Japan) and Dai-Nippon (Japan).[15] OptiGraphics Corporation of Grand Prairie, Texas[27] was formed in 1970 and—under the guidance of Victor Anderson, working well into his 80s. The company trademarked Magic Motion in 1976.[28] Optigraphics produced the lenticular prizes for Cracker Jack in the 1980s, 7-Eleven Slurpee lenticular sports coins from 1983 to 1987,[29] and in 1986 it produced the first set of 3D traditional baseball cards marketed as Sportflics, which ultimately led to the creation of Pinnacle Brands.[30] In 1999 Performance Companies bought OptiGraphics after Pinnacle Trading Card Company went bankrupt in 1998.[27] While lenticular images were very popular in the 1960s and 1970s, by the 1980s OptiGraphics was the only significant manufacturer left in the US.[15] 21st century The techniques for lenticular printing were further improved in the 21st century. Lenticular full motion video effects or "motion print" enabled viewing of up to 60 video frames within a print. Common and notable products Political campaign and pop star "flasher" badges After their first presidential campaign badge I like Ike in 1952, Pictorial Productions Inc. made many more similar political campaign buttons, including presidential campaign badge like Don't blame me! - I voted democratic (1956), John F. Kennedy - The Man for the 60s (1960), I Like Ben (1963) and I'm for Nixon (1968?).[31] Official "flasher" badges for pop stars like Elvis Presley were manufactured by Vari-Vue at least since 1956,[32] including badges for Beatles, Rolling Stones' and other bands in the 1960s. Cheerios and Cracker Jack prizes Pictorial Productions/Vari-Vue produced small animated picture cards for Cheerios in the 1950s, of which founder Victor Anderson claimed to have produced 40 million. He also stated that the cards were originally stuck to the outside of the packaging and were only put inside the boxes after too many cards were stolen before the boxes reached the store shelves.[19] Many different lenticular "tilt cards" were produced as prizes in Cracker Jack boxes. These were first produced by Vari-Vue (1950s-1970s), later by Toppan Printing, Ltd. (1980s), and Optigraphics Corporation (1980s-1990s).[33] Novelty toys In 1958 Victor Anderson patented an Ocular Toy: an eye glass mount with lenticular winking eyes.[34] Lenticular images were used in many small and cheap plastic toys, often as gumball machine prizes. These include: miniature toy televisions with an animated lenticular screen, charms in the shape of animals with lenticular faces, "flicker rings", etcetera. In 1960 Takara's Dakkochan - a little plastic golliwog toy with lenticular eyes - originally intended for toddlers, became very popular with Japanese teenagers as a fashion accessory worn around the arm.[35] Postcards Around 1966 several companies started producing lenticular postcards. Common themes are winking girls, religious scenes, animals, dioramas with dolls, touristic sites and pin-up models wearing clothes when viewed from one angle and nude when viewed from another angle. Covers for books, music albums and movies The lenticular picture on the album cover for the Rolling Stones' 1967 LP Their Satanic Majesties Request was manufactured by Vari-Vue, as well as the postcards and other promotional items that accompanied the release.[36] Other lenticular LP covers include Johnny Cash's The Holy Land (1969)[37] and The Stranglers' The Raven.[38] In the 2010s lenticular covers for LPs became a bit more common, especially for deluxe re-releases.[39] Saturnalia 1973 LP with lenticular label that switches from "Magical love" to a logo. In 1973 the band Saturnalia had lenticular labels on their Magical Love picture disc lp.[40] From around the mid-1990s some lenticular cd covers were produced (mostly for limited editions), including Pet Shop Boys' Alternative (1995) with an image of Chris changing into Neil,[41] The Sacrilicious Sounds of the Supersuckers (1995),[42] Tool's Ænima (1996), Velvet Underground's Loaded 2CD version (1997),[43] Kraftwerk Expo2000 (1999) and David Bowie's Hours (1999).[44] Ministry's 2007 The last sucker had an image of George W. Bush changing into a monstrous, alien-like face.[45] In the 2010s lenticular covers for movies on DVD and Blu-ray became quite common. Lenticular covers have also been used as a collectible cover variant for comic books since the 1990s; Marvel, DC, and other publishers have created such covers with animated or 3-D effects.[46] Lentograph In August 1967 the trademark Lentograph was filed by Victor Anderson 3D Studios, Inc. (registered in October 1968).[47][48] Lentographs were marketed as relatively large lenticular plates (16 x 12 inches / 12 × 8 inches), often found in an illuminated brass frame. Commonly found are 3D pictures of Paul Cunningham's biblical displays with sculpted figurines in dramatic poses based on paintings (Plate 501-508), a family of teddy bears in a domestic scene, Plate No. 106 Evening Flowers, Plate No. 115 Goldilocks and 3 bears, Plate No. 124 Bijou (a white poodle), Plate No. 121 Midday Respite (a taxidermied young deer in a forest setting), Plate No. 213 Red Riding Hood. Also known are a harbor scene (Plate No. 114), Plate No. 118 Japanese Floral, Plate No. 123 Faustus (a yorky dog) and Plate No. 212 of a covered bridge.[49] Lenticular postage stamps In 1967 Bhutan introduced lenticular 3D postage stamps as one of the many unusual stamp designs of the Bhutan Stamp Agency initiated by American businessman Burt Kerr Todd.[50][51] Countries like Ajman, Yemen, Manama, Umm Al Qiwain and North Korea released lenticular stamps in the 1970s. Animated lenticular stamps have been issued since the early 1980s by countries like North Korea.[52] In 2004 full motion lenticular postage stamps were issued in New Zealand. Over the years many other countries have produced stamps with similar lenticular full motion effects, mostly depicting sport events.[52] In 2010 Communications agency KesselsKramer produced the "Smallest Shortest Film" on a Dutch stamp, directed by Anton Corbijn and featuring actress Carice van Houten.[53] In 2012, Design Consultancy GBH.London created the UK's first 'Motion Stamps' for Royal Mail's Special Stamp Issue, The Genius of Gerry Anderson. The minisheet featured four fully lenticular stamps based on Gerry and Sylvia Anderson's Thunderbirds TV series. The Stamps and their background border used 48 frame 'MotionPrint’ technology and were produced by Outer Aspect from New Zealand. In August 2018 the United States Postal Service introduced "The Art of Magic" lenticular stamp, sold in a souvenir sheet of three. The stamp was designed to celebrate the art of magic and "by rotating each stamp, you can see a white rabbit popping out of a black top hat."[54] In August 2019 the United States Postal Service introduced a second stamp with lenticular technology, this time featuring the dinosaur Tyrannosaurus Rex. The USPS explained that "two of the four designs show movement when rotated. See the skeletal remains with and without flesh and watch as an approaching T. rex suddenly lunges forward."[55] Books In 2012, Dan Kainen's first "photicular" book Safari was published, with processed video images animated by having a lens sheet slide by turning the page,[56] much like Rufus Butler Seder's "scanimation" process. It was followed by Ocean (2014), Polar (2015), Jungle (2016), Wild (2017), Dinosaur (2018) and Outback (2019). Related techniques Han-O-Disc manufactured for Light Fantastic with metal flake outside and Dufex process print within. Han-O-Disc record with diffraction grating 'Rainbow' film (outside ring), color shifting Rowlux (middle ring) and "silver balls" Rowlux film (center of record). A related product, produced by a small company in New Jersey, was Rowlux. Unlike the Vari-Vue product, Rowlux used a microprismatic lens structure made by a process they patented in 1972,[57] and no paper print. Instead, the plastic (polycarbonate, flexible PVC and later PETG) was dyed with translucent colors, and the film was usually thin and flexible (from 0.002" or 0.051 mm in thickness). While not a true lenticular process, the Dufex Process (manufactured by F.J. Warren Ltd.)[58] does use a form of lens structure to animate the image. The process consists of imprinting a metallic foil with an image. The foil is then laminated onto a thin sheet of card stock that has been coated with a thick layer of wax. The heated lamination press has the Dufex embossing plate on its upper platen, which has been engraved with 'lenses' at different angles, designed to match the artwork and reflect light at different intensities depending on angle of view. Lenticular cinema and television Since at least the early 1930s many researchers have tried to develop lenticular cinema. Herbert E. Ives presented an apparatus on 31 October 1930 with small autostereoscopic motion pictures viewable by only small groups at a time. Ives would continue to improve his system over the years. However, producing autostereoscopic movies was deemed too costly for commercial purposes. A November 1931 New York Times article entitled New screens gives depth to movies describes a lenticular system by Douglas F. Winnek and also mentions an optical appliance fitted near the screen by South African astronomer R.T.A. Innes.[59] Lenticular arrays have also been used for 3D autostereoscopic television, which produces the illusion of 3D vision without the use of special glasses. At least as early as 1954 patents for lenticular television were filed,[60] but it lasted until 2010 before a range of 3D televisions became available. Some of these systems used cylindrical lenses slanted from the vertical, or spherical lenses arranged in a honeycomb pattern, to provide a better resolution. While over 40 million 3D televisions were sold in 2012 (including systems that required glasses),[61] by 2016 very little 3D content was offered and manufacturers had stopped producing 3D TV sets. While the need to wear glasses for the more affordable systems seemed to have been a letdown for customers, affordable autostereoscopic televisions were seen as a future solution.[62] Further information: 3D television Manufacturing process Printing Lenticular front sheeting and image-processing software are both sold for home computer printing, where the interlaced image backing is inkjet printed in photo resolution and affixed behind the lenticular sheet. [63] Creation of lenticular images on a commercial scale requires printing presses that are adapted to print on sensitive thermoplastic materials. Lithographic offset printing is typically used, to ensure the images are good quality. Printing presses for lenticulars must be capable of adjusting image placement in 10-µm steps, to allow good alignment of the image to the lens array. Typically, ultraviolet-cured inks are used. These dry very quickly by direct conversion of the liquid ink to a solid form, rather than by evaporation of liquid solvents from a mixture. Powerful (400-watt-per-square-inch or 0.083 hp/cm2) ultraviolet (UV) lamps have been used to rapidly cure the ink. This allowed lenticular images to be printed at high speed. In some cases, electron beam lithography has been used instead. The curing of the ink was then initiated directly by an electron beam scanned across the surface. Defects Design defects Double images on the relief and in depth Double images are usually caused by an exaggeration of the 3D effect from some angles of view, or an insufficient number of frames. Poor design can lead to doubling, small jumps, or a fuzzy image, especially on objects in relief or in depth. For some visuals, where the foreground and background are fuzzy or shaded, this exaggeration can prove to be an advantage. In most cases, the detail and precision required do not allow this. Image ghosting Ghosting occurs due to poor treatment of the source images, and also due to transitions where demand for an effect goes beyond the limits and technical possibilities of the system. This causes some of the images to remain visible when they should disappear. These effects can depend on the lighting of the lenticular print. Prepress defects Synchronization of the print (master) with the pitch This effect is also known as "banding". Poor calibration of the material can cause the passage from one image to another to not be simultaneous over the entire print. The image transition progresses from one side of the print to the other, giving the impression of a veil or curtain crossing the visual. This phenomenon is felt less for the 3D effects, but is manifested by a jump of the transverse image. In some cases, the transition starts in several places and progresses from each starting point towards the next, giving the impression of several curtains crossing the visual, as described above. Discordant harmonics This phenomenon is unfortunately very common, and is explained either by incorrect calibration of the support or by incorrect parametrization of the prepress operations. It is manifested in particular by streaks that appear parallel to the lenticules during transitions from one visual to the other. Printing defects Color synchronization One of the main difficulties in lenticular printing is color synchronization. The causes are varied, they may come from a malleable material, incorrect printing conditions and adjustments, or again a dimensional differential of the engraving of the offset plates in each color. This poor marking is shown by doubling of the visual; a lack of clarity; a streak of color or wavy colors (especially for four-color shades) during a change of phase by inclination of the visual. Synchronization of parallelism of the printing to the lenticules The origin of this problem is a fault in the printing and forcibly generates a phase defect. The passage from one visual to another must be simultaneous over the entire format. But when this problem occurs, there is a lag in the effects on the diagonals. At the end of one diagonal of the visual, there is one effect, and at the other end, there is another. Phasing In most cases, the phasing problem comes from imprecise cutting of the material, as explained below. Nevertheless, poor printing and rectification conditions may also be behind it. In theory, for a given angle of observation, one and the same visual must appear, for the entire batch. As a general rule, the angle of vision is around 45°, and this angle must be in agreement with the sequence provided by the master. If the images have a tendency to double perpendicularly (for 3D) or if the images provided for observation to the left appear to the right (top/bottom), then there is a phasing problem. Cutting defects Defects, in the way the lenticular lens has been cut, can lead to phase errors between the lens and the image. Two examples, taken from the same production batch: First image     Second image The first image shows a cut which removed about 150 µm of the first lens, and which shows irregular cutting of the lenticular lenses. The second image shows a cut which removed about 30 µm of the first lens. Defects in cutting such as these lead to a serious phase problem. In the printing press the image being printed is aligned relative to the edges of the sheet of material. If the sheet is not always cut in the same place relative to the first lenticule, a phase error is introduced between the lenses and the image slices. " (wikipedia.org) "A 3D display is a display device capable of conveying depth to the viewer. Many 3D displays are stereoscopic displays, which produce a basic 3D effect by means of stereopsis, but can cause eye strain and visual fatigue. Newer 3D displays such as holographic and light field displays produce a more realistic 3D effect by combining stereopsis and accurate focal length for the displayed content. Newer 3D displays in this manner cause less visual fatigue than classical stereoscopic displays. As of 2021, the most common type of 3D display is a stereoscopic display, which is the type of display used in almost all virtual reality equipment. 3D displays can be near-eye displays like in VR headsets, or they can be in a device further away from the eyes like a 3D-enabled mobile device or 3D movie theater. The term “3D display” can also be used to refer to a volumetric display which may generate content that can be viewed from all angles. History The first 3D display was created by Sir Charles Wheatstone in 1832.[1] It was a stereoscopic display that had rudimentary ability for representing depth. Stereoscopic displays Main article: Stereoscopy Stereoscopic displays are commonly referred to as “stereo displays,” “stereo 3D displays,” “stereoscopic 3D displays,” or sometimes erroneously as just “3D displays.” The basic technique of stereo displays is to present offset images that are displayed separately to the left and right eye. Both of these 2D offset images are then combined in the brain to give the perception of 3D depth. Although the term "3D" is ubiquitously used, it is important to note that the presentation of dual 2D images is distinctly different from displaying a light field, and is also different from displaying an image in three-dimensional space. The most notable difference to real 3D displays is that the observer's head and eyes movements will not increase information about the 3D objects being displayed. For example, holographic displays do not have such limitations. It is an overstatement of capability to refer to dual 2D images as being "3D". The accurate term "stereoscopic" is more cumbersome than the common misnomer "3D", which has been entrenched after many decades of unquestioned misuse. Although most stereoscopic displays do not qualify as real 3D displays, all real 3D displays are often referred to as also stereoscopic displays because they meet the lower criteria of being stereoscopic as well. Based on the principles of stereopsis, described by Sir Charles Wheatstone in the 1830s, stereoscopic technology provides a different image to the viewer's left and right eyes. The following are some of the technical details and methodologies employed in some of the more notable stereoscopic systems that have been developed. Side-by-side images "The early bird catches the worm" Stereograph published in 1900 by North-Western View Co. of Baraboo, Wisconsin, digitally restored. Traditional stereoscopic photography consists of creating a 3D illusion starting from a pair of 2D images, a stereogram. The easiest way to enhance depth perception in the brain is to provide the eyes of the viewer with two different images, representing two perspectives of the same object, with a minor deviation exactly equal to the perspectives that both eyes naturally receive in binocular vision. If eyestrain and distortion are to be avoided, each of the two 2D images preferably should be presented to each eye of the viewer so that any object at infinite distance seen by the viewer should be perceived by that eye while it is oriented straight ahead, the viewer's eyes being neither crossed nor diverging. When the picture contains no object at infinite distance, such as a horizon or a cloud, the pictures should be spaced correspondingly closer together. The side-by-side method is extremely simple to create, but it can be difficult or uncomfortable to view without optical aids. Stereoscope and stereographic cards Main article: Stereoscope A stereoscope is a device for viewing stereographic cards, which are cards that contain two separate images that are printed side by side to create the illusion of a three-dimensional image. Transparency viewers Main article: Slide viewer § Stereo slide viewer A View-Master Model E of the 1950s Pairs of stereo views printed on a transparent base are viewed by transmitted light. One advantage of transparency viewing is the opportunity for a wider, more realistic dynamic range than is practical with prints on an opaque base; another is that a wider field of view may be presented since the images, being illuminated from the rear, may be placed much closer to the lenses. The practice of viewing film-based stereoscopic transparencies dates to at least as early as 1931, when Tru-Vue began to market sets of stereo views on strips of 35 mm film that were fed through a hand-held Bakelite viewer. In 1939, a modified and miniaturized variation of this technology, employing cardboard disks containing seven pairs of small Kodachrome color film transparencies, was introduced as the View-Master. Head-mounted displays Main articles: Head-mounted display and Virtual retinal display The user typically wears a helmet or glasses with two small LCD or OLED displays with magnifying lenses, one for each eye. The technology can be used to show stereo films, images or games. Head-mounted displays may also be coupled with head-tracking devices, allowing the user to "look around" the virtual world by moving their head, eliminating the need for a separate controller. Owing to rapid advancements in computer graphics and the continuing miniaturization of video and other equipment these devices are beginning to become available at more reasonable cost. Head-mounted or wearable glasses may be used to view a see-through image imposed upon the real world view, creating what is called augmented reality. This is done by reflecting the video images through partially reflective mirrors. The real world can be seen through the partial mirror. A recent development in holographic-waveguide or "waveguide-based optics" allows a stereoscopic images to be superimposed on real world without the uses of bulky reflective mirror.[2][3] Head-mounted projection displays Head-mounted projection displays (HMPD) is similar to head-mounted displays but with images projected to and displayed on a retroreflective screen, The advantage of this technology over head-mounted display is that the focusing and vergence issues didn't require fixing with corrective eye lenses. For image generation, Pico-projectors are used instead of LCD or OLED screens.[4][5] Anaglyph Main article: Anaglyph 3D The archetypal 3D glasses, with modern red and cyan color filters, similar to the red/green and red/blue lenses used to view early anaglyph films. In an anaglyph, the two images are superimposed in an additive light setting through two filters, one red and one cyan. In a subtractive light setting, the two images are printed in the same complementary colors on white paper. Glasses with colored filters in each eye separate the appropriate image by canceling the filter color out and rendering the complementary color black. A compensating technique, commonly known as Anachrome, uses a slightly more transparent cyan filter in the patented glasses associated with the technique. Process reconfigures the typical anaglyph image to have less parallax. An alternative to the usual red and cyan filter system of anaglyph is ColorCode 3-D, a patented anaglyph system which was invented in order to present an anaglyph image in conjunction with the NTSC television standard, in which the red channel is often compromised. ColorCode uses the complementary colors of yellow and dark blue on-screen, and the colors of the glasses' lenses are amber and dark blue. Polarization systems Resembling sunglasses, RealD circular polarized glasses are now the standard for theatrical releases and theme park attractions. Main article: Polarized 3D system To present a stereoscopic picture, two images are projected superimposed onto the same screen through different polarizing filters. The viewer wears eyeglasses which also contain a pair of polarizing filters oriented differently (clockwise/counterclockwise with circular polarization or at 90 degree angles, usually 45 and 135 degrees,[6] with linear polarization). As each filter passes only that light which is similarly polarized and blocks the light polarized differently, each eye sees a different image. This is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from slightly different perspectives. Additionally, since both lenses have the same color, people with one dominant eye, where one eye is used more, are able to see the colors properly, previously negated by the separation of the two colors. Circular polarization has an advantage over linear polarization, in that the viewer does not need to have their head upright and aligned with the screen for the polarization to work properly. With linear polarization, turning the glasses sideways causes the filters to go out of alignment with the screen filters causing the image to fade and for each eye to see the opposite frame more easily. For circular polarization, the polarizing effect works regardless of how the viewer's head is aligned with the screen such as tilted sideways, or even upside down. The left eye will still only see the image intended for it, and vice versa, without fading or crosstalk. Polarized light reflected from an ordinary motion picture screen typically loses most of its polarization. So an expensive silver screen or aluminized screen with negligible polarization loss has to be used. All types of polarization will result in a darkening of the displayed image and poorer contrast compared to non-3D images. Light from lamps is normally emitted as a random collection of polarizations, while a polarization filter only passes a fraction of the light. As a result, the screen image is darker. This darkening can be compensated by increasing the brightness of the projector light source. If the initial polarization filter is inserted between the lamp and the image generation element, the light intensity striking the image element is not any higher than normal without the polarizing filter, and overall image contrast transmitted to the screen is not affected. Eclipse method A pair of LCD shutter glasses used to view XpanD 3D films. The thick frames conceal the electronics and batteries. Main article: Active shutter 3D system With the eclipse method, a shutter blocks light from each appropriate eye when the converse eye's image is projected on the screen. The display alternates between left and right images, and opens and closes the shutters in the glasses or viewer in synchronization with the images on the screen. This was the basis of the Teleview system which was used briefly in 1922.[7][8] A variation on the eclipse method is used in LCD shutter glasses. Glasses containing liquid crystal that will let light through in synchronization with the images on the cinema, television or computer screen, using the concept of alternate-frame sequencing. This is the method used by nVidia, XpanD 3D, and earlier IMAX systems. A drawback of this method is the need for each person viewing to wear expensive, electronic glasses that must be synchronized with the display system using a wireless signal or attached wire. The shutter-glasses are heavier than most polarized glasses, though lighter models are no heavier than some sunglasses or deluxe polarized glasses.[9] However these systems do not require a silver screen for projected images. Liquid crystal light valves work by rotating light between two polarizing filters. Due to these internal polarizers, LCD shutter-glasses darken the display image of any LCD, plasma, or projector image source, which has the result that images appear dimmer and contrast is lower than for normal non-3D viewing. This is not necessarily a usage problem; for some types of displays which are already very bright with poor grayish black levels, LCD shutter glasses may actually improve the image quality. Interference filter technology Main article: Anaglyph 3D § Interference filter systems Dolby 3D uses specific wavelengths of red, green, and blue for the right eye, and different wavelengths of red, green, and blue for the left eye. Eyeglasses which filter out the very specific wavelengths allow the wearer to see a 3D image. This technology eliminates the expensive silver screens required for polarized systems such as RealD, which is the most common 3D display system in theaters. It does, however, require much more expensive glasses than the polarized systems. It is also known as spectral comb filtering or wavelength multiplex visualization The recently introduced Omega 3D/Panavision 3D system also uses this technology, though with a wider spectrum and more "teeth" to the "comb" (5 for each eye in the Omega/Panavision system). The use of more spectral bands per eye eliminates the need to color process the image, required by the Dolby system. Evenly dividing the visible spectrum between the eyes gives the viewer a more relaxed "feel" as the light energy and color balance is nearly 50-50. Like the Dolby system, the Omega system can be used with white or silver screens. But it can be used with either film or digital projectors, unlike the Dolby filters that are only used on a digital system with a color correcting processor provided by Dolby. The Omega/Panavision system also claims that their glasses are cheaper to manufacture than those used by Dolby.[10] In June 2012, the Omega 3D/Panavision 3D system was discontinued by DPVO Theatrical, who marketed it on behalf of Panavision, citing "challenging global economic and 3D market conditions".[citation needed] Although DPVO dissolved its business operations, Omega Optical continues promoting and selling 3D systems to non-theatrical markets. Omega Optical’s 3D system contains projection filters and 3D glasses. In addition to the passive stereoscopic 3D system, Omega Optical has produced enhanced anaglyph 3D glasses. The Omega’s red/cyan anaglyph glasses use complex metal oxide thin film coatings and high quality annealed glass optics. Autostereoscopy Main article: Autostereoscopy The Nintendo 3DS uses parallax barrier autostereoscopy to display a 3D image. In this method, glasses are not necessary to see the stereoscopic image. Lenticular lens and parallax barrier technologies involve imposing two (or more) images on the same sheet, in narrow, alternating strips, and using a screen that either blocks one of the two images' strips (in the case of parallax barriers) or uses equally narrow lenses to bend the strips of image and make it appear to fill the entire image (in the case of lenticular prints). To produce the stereoscopic effect, the person must be positioned so that one eye sees one of the two images and the other sees the other. The optical principles of multiview auto-stereoscopy have been known for over a century.[11] Both images are projected onto a high-gain, corrugated screen which reflects light at acute angles. In order to see the stereoscopic image, the viewer must sit within a very narrow angle that is nearly perpendicular to the screen, limiting the size of the audience. Lenticular was used for theatrical presentation of numerous shorts in Russia from 1940 to 1948[12] and in 1946 for the feature-length film Robinzon Kruzo[13] Though its use in theatrical presentations has been rather limited, lenticular has been widely used for a variety of novelty items and has even been used in amateur 3D photography.[14][15] Recent use includes the Fujifilm FinePix Real 3D with an autostereoscopic display that was released in 2009. Other examples for this technology include autostereoscopic LCD displays on monitors, notebooks, TVs, mobile phones and gaming devices, such as the Nintendo 3DS. Other Main article: Stereoscopy The Pulfrich effect is a psychophysical percept wherein lateral motion of an object in the field of view is interpreted by the visual cortex as having a depth component, due to a relative difference in signal timings between the two eyes. Prismatic glasses make cross-viewing easier as well as over/under-viewing possible, examples include the KMQ viewer. Volumetric display Main article: Volumetric display Volumetric 3D display Volumetric displays use some physical mechanism to display points of light within a volume. Such displays use voxels instead of pixels. Volumetric displays include multiplanar displays, which have multiple display planes stacked up, and rotating panel displays, where a rotating panel sweeps out a volume. Other technologies have been developed to project light dots in the air above a device. An infrared laser is focused on the destination in space, generating a small bubble of plasma which emits visible light. Light field / holographic display A light field display tries to recreate a "light field" on the surface of the display. In contrast to a 2D display which shows a distinct color on each pixel, a light field display shows a distinct color on each pixel for each direction that the light ray emits to. This way, eyes from different positions will see different pictures on the display, creating parallax and thus creating a sense of 3D. A light field display is like a glass window, people see 3D objects behind the glass, despite that all light rays they see come from (through) the glass. The light field in front of the display can be created in two ways: 1) by emitting different light rays in different directions at each point on the display; 2) by recreating a wavefront in front of the display. Displays using the first method are called ray-based or light field displays. Displays using the second method are called wavefront-based or holographic displays. Wavefront-based displays work in the same way as holograms. Compared to ray-based displays, a wavefront-based display not only reconstructs the light field, but also reconstructs the curvature of the plane waves, and the phase differences of the waves in different directions.[16] Integral photography is one of the ray-based methods with full-parallax information. However, there are also ray-based techniques developed with horizontal-parallax-only.[16] Holographic displays Main articles: Holographic display and Computer-generated holography Holographic display is a display technology that has the ability to provide all four eye mechanisms: binocular disparity, motion parallax, accommodation and convergence. The 3D objects can be viewed without wearing any special glasses and no visual fatigue will be caused to human eyes. In 2013, a Silicon valley Company LEIA Inc started manufacturing holographic displays well suited for mobile devices (watches, smartphones or tablets) using a multi-directional backlight and allowing a wide full-parallax angle view to see 3D content without the need of glasses.[17] Their first product was part of a mobile phone (Red Hydrogen One) and later on in their own Android tablet.[citation needed] Integral imaging Main article: Integral imaging Integral imaging is an autostereoscopic or multiscopic 3D display, meaning that it displays a 3D image without the use of special glasses on the part of the viewer. It achieves this by placing an array of microlenses (similar to a lenticular lens) in front of the image, where each lens looks different depending on viewing angle. Thus rather than displaying a 2D image that looks the same from every direction, it reproduces a 3D light field, creating stereo images that exhibit parallax when the viewer moves. Compressive light field displays A new display technology called "compressive light field" is being developed. These prototype displays use layered LCD panels and compression algorithms at the time of display. Designs include dual[18] and multilayer[19][20][21] devices that are driven by algorithms such as computed tomography and Non-negative matrix factorization and non-negative tensor factorization." (wikipedia.org) "In geometry, a three-dimensional space (3D space, 3-space or, rarely, tri-dimensional space) is a mathematical space in which three values (coordinates) are required to determine the position of a point. Most commonly, it is the three-dimensional Euclidean space, the Euclidean n-space of dimension n=3 that models physical space. More general three-dimensional spaces are called 3-manifolds. Technically, a tuple of n numbers can be understood as the Cartesian coordinates of a location in a n-dimensional Euclidean space. The set of these n-tuples is commonly denoted R n , {\displaystyle \mathbb {R} ^{n},} {\displaystyle \mathbb {R} ^{n},} and can be identified to the pair formed by a n-dimensional Euclidean space and a Cartesian coordinate system. When n = 3, this space is called the three-dimensional Euclidean space (or simply "Euclidean space" when the context is clear).[1] It serves as a model of the physical universe (when relativity theory is not considered), in which all known matter exists. While this space remains the most compelling and useful way to model the world as it is experienced,[2] it is only one example of a large variety of spaces in three dimensions called 3-manifolds. In this classical example, when the three values refer to measurements in different directions (coordinates), any three directions can be chosen, provided that vectors in these directions do not all lie in the same 2-space (plane). Furthermore, in this case, these three values can be labeled by any combination of three chosen from the terms width/breadth, height/depth, and length. History Books XI to XIII of Euclid's Elements dealt with three-dimensional geometry. Book XI develops notions of orthogonality and parallelism of lines and planes, and defines solids including parallelpipeds, pyramids, prisms, spheres, octahedra, icosahedra and dodecahedra. Book XII develops notions of similarity of solids. Book XIII describes the construction of the five regular Platonic solids in a sphere. In the 17th century, three-dimensional space was described with Cartesian coordinates, with the advent of analytic geometry developed by René Descartes in his work La Géométrie and Pierre de Fermat in the manuscript Ad locos planos et solidos isagoge (Introduction to Plane and Solid Loci), which was unpublished during Fermat's lifetime. However, only Fermat's work dealt with three-dimensional space. In the 19th century, developments of the geometry of three-dimensional space came with William Rowan Hamilton's development of the quaternions. In fact, it was Hamilton who coined the terms scalar and vector, and they were first defined within his geometric framework for quaternions. Three dimensional space could then be described by quaternions q = a + u i + v j + w k {\displaystyle q=a+ui+vj+wk} {\displaystyle q=a+ui+vj+wk} which had vanishing scalar component, that is, a = 0 {\displaystyle a=0} a=0. While not explicitly studied by Hamilton, this indirectly introduced notions of basis, here given by the quaternion elements i , j , k {\displaystyle i,j,k} i,j,k, as well as the dot product and cross product, which correspond to (the negative of) the scalar part and the vector part of the product of two vector quaternions. It was not until Josiah Willard Gibbs that these two products were identified in their own right, and the modern notation for the dot and cross product were introduced in his classroom teaching notes, found also in the 1901 textbook Vector Analysis written by Edwin Bidwell Wilson based on Gibbs' lectures. Also during the 19th century came developments in the abstract formalism of vector spaces, with the work of Hermann Grassmann and Giuseppe Peano, the latter of whom first gave the modern definition of vector spaces as an algebraic structure." (wikipedia.org) "The National Aeronautics and Space Administration (NASA /ˈnæsə/) is an independent agency of the U.S. federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding the National Advisory Committee for Aeronautics (NACA), to give the U.S. space development effort a distinctly civilian orientation, emphasizing peaceful applications in space science.[5][6][7] NASA has since led most American space exploration, including Project Mercury, Project Gemini, the 1968–1972 Apollo Moon landing missions, the Skylab space station, and the Space Shuttle. NASA supports the International Space Station and oversees the development of the Orion spacecraft and the Space Launch System for the crewed lunar Artemis program, Commercial Crew spacecraft, and the planned Lunar Gateway space station. The agency is also responsible for the Launch Services Program, which provides oversight of launch operations and countdown management for uncrewed NASA launches. NASA's science is focused on better understanding Earth through the Earth Observing System;[8] advancing heliophysics through the efforts of the Science Mission Directorate's Heliophysics Research Program;[9] exploring bodies throughout the Solar System with advanced robotic spacecraft such as New Horizons and planetary rovers such as Perseverance;[10] and researching astrophysics topics, such as the Big Bang, through the James Webb Space Telescope, and the Great Observatories and associated programs.[11] Management Leadership Administrator Bill Nelson (2021–present) The agency's administration is located at NASA Headquarters in Washington, DC, and provides overall guidance and direction.[12] Except under exceptional circumstances, NASA civil service employees are required to be US citizens.[13] NASA's administrator is nominated by the President of the United States subject to the approval of the US Senate,[14] and serves at the President's pleasure as a senior space science advisor. The current administrator is Bill Nelson, appointed by President Joe Biden, since May 3, 2021.[15] Strategic plan NASA operates with four FY2022 strategic goals.[16]     Expand human knowledge through new scientific discoveries     Extend human presence to the Moon and on towards Mars for sustainable long-term exploration, development, and utilization     Catalyze economic growth and drive innovation to address national challenges     Enhance capabilities and operations to catalyze current and future mission success Budget Further information: Budget of NASA NASA budget requests are developed by NASA and approved by the administration prior to submission to the U.S. Congress. Authorized budgets are those that have been included in enacted appropriations bills that are approved by both houses of Congress and enacted into law by the U.S. president.[17] NASA funding and priorities are developed through its six Mission Directorates. Center-wide activities such as the Chief Engineer and Safety and Mission Assurance organizations are aligned to the headquarters function. The MSD budget estimate includes funds for these HQ functions. The administration operates 10 major field centers with several managing additional subordinate facilities across the country. Each is led by a Center Director (data below valid as of September 1, 2022). Field Center     Primary Location     Center Director Ames Research Center     Mountain View, California     Dr. Eugene L. Tu[33] Armstrong Flight Research Center     Palmdale, California     Brad Flick (acting)[34] Glenn Research Center     Cleveland, Ohio     Dr. James A. Kenyon (acting)[35] Goddard Space Flight Center     Greenbelt, Maryland     Dr. Makenzie Lystrup[36] Jet Propulsion Laboratory     La Canada-Flintridge, California     Laurie Leshin[37] Johnson Space Center     Houston, Texas     Vanessa E. Wyche[38] Kennedy Space Center     Merritt Island, Florida     Janet Petro[39] Langley Research Center     Hampton, Virginia     Clayton Turner[40] Marshall Space Flight Center     Huntsville, Alabama     Jody Singer[41] Stennis Space Center     Hancock County, Mississippi     Richard J. Gilbrech[42] History Establishment of NASA Further information: Creation of NASA, NASA's Space Place, and Science Mission Directorate Short 2018 documentary about NASA produced for its 60th anniversary Beginning in 1946, the National Advisory Committee for Aeronautics (NACA) began experimenting with rocket planes such as the supersonic Bell X-1.[43] In the early 1950s, there was challenge to launch an artificial satellite for the International Geophysical Year (1957–1958). An effort for this was the American Project Vanguard. After the Soviet space program's launch of the world's first artificial satellite (Sputnik 1) on October 4, 1957, the attention of the United States turned toward its own fledgling space efforts. The US Congress, alarmed by the perceived threat to national security and technological leadership (known as the "Sputnik crisis"), urged immediate and swift action; President Dwight D. Eisenhower counseled more deliberate measures. The result was a consensus that the White House forged among key interest groups, including scientists committed to basic research; the Pentagon which had to match the Soviet military achievement; corporate America looking for new business; and a strong new trend in public opinion looking up to space exploration.[44] On January 12, 1958, NACA organized a "Special Committee on Space Technology", headed by Guyford Stever.[7] On January 14, 1958, NACA Director Hugh Dryden published "A National Research Program for Space Technology", stating,[45]     It is of great urgency and importance to our country both from consideration of our prestige as a nation as well as military necessity that this challenge [Sputnik] be met by an energetic program of research and development for the conquest of space ... It is accordingly proposed that the scientific research be the responsibility of a national civilian agency ... NACA is capable, by rapid extension and expansion of its effort, of providing leadership in space technology.[45] While this new federal agency would conduct all non-military space activity, the Advanced Research Projects Agency (ARPA) was created in February 1958 to develop space technology for military application.[46] On July 29, 1958, Eisenhower signed the National Aeronautics and Space Act, establishing NASA.[47] When it began operations on October 1, 1958, NASA absorbed the 43-year-old NACA intact; its 8,000 employees, an annual budget of US$100 million, three major research laboratories (Langley Aeronautical Laboratory, Ames Aeronautical Laboratory, and Lewis Flight Propulsion Laboratory) and two small test facilities.[48] Elements of the Army Ballistic Missile Agency and the United States Naval Research Laboratory were incorporated into NASA. A significant contributor to NASA's entry into the Space Race with the Soviet Union was the technology from the German rocket program led by Wernher von Braun, who was now working for the Army Ballistic Missile Agency (ABMA), which in turn incorporated the technology of American scientist Robert Goddard's earlier works.[49] Earlier research efforts within the US Air Force[48] and many of ARPA's early space programs were also transferred to NASA.[50] In December 1958, NASA gained control of the Jet Propulsion Laboratory, a contractor facility operated by the California Institute of Technology.[48] Past administrators Further information: Administrator of NASA NASA's first administrator was Dr. T. Keith Glennan who was appointed by President Dwight D. Eisenhower. During his term (1958–1961) he brought together the disparate projects in American space development research.[51] James Webb led the agency during the development of the Apollo program in the 1960s.[52] James C. Fletcher has held the position twice; first during the Nixon administration in the 1970s and then at the request of Ronald Reagan following the Challenger disaster.[53] Daniel Goldin held the post for nearly 10 years and is the longest serving administrator to date. He is best known for pioneering the "faster, better, cheaper" approach to space programs.[54] Bill Nelson is currently serving as the 14th administrator of NASA. Insignia Further information: NASA insignia The NASA seal was approved by Eisenhower in 1959, and slightly modified by President John F. Kennedy in 1961.[55][56] NASA's first logo was designed by the head of Lewis' Research Reports Division, James Modarelli, as a simplification of the 1959 seal.[57] In 1975, the original logo was first dubbed "the meatball" to distinguish it from the newly designed "worm" logo which replaced it. The "meatball" returned to official use in 1992.[57] The "worm" was brought out of retirement by administrator Jim Bridenstine in 2020.[58] Facilities Further information: NASA facilities NASA Headquarters in Washington, DC provides overall guidance and political leadership to the agency's ten field centers, through which all other facilities are administered.[59] Aerial views of the NASA Ames (left) and NASA Armstrong (right) centers Ames Research Center (ARC) at Moffett Field is located in the Silicon Valley of central California and delivers wind-tunnel research on the aerodynamics of propeller-driven aircraft along with research and technology in aeronautics, spaceflight, and information technology.[60] It provides leadership in astrobiology, small satellites, robotic lunar exploration, intelligent/adaptive systems and thermal protection. Armstrong Flight Research Center (AFRC) is located inside Edwards Air Force Base and is the home of the Shuttle Carrier Aircraft (SCA), a modified Boeing 747 designed to carry a Space Shuttle orbiter back to Kennedy Space Center after a landing at Edwards AFB. The center focuses on flight testing of advanced aerospace systems. Glenn Research Center is based in Cleveland, Ohio and focuses on air-breathing and in-space propulsion and cryogenics, communications, power energy storage and conversion, microgravity sciences, and advanced materials.[61] View of GSFC campus (left) and Kraft Mission Control Center at JSC (right) Goddard Space Flight Center (GSFC), located in Greenbelt, Maryland develops and operates uncrewed scientific spacecraft.[62] GSFC also operates two spaceflight tracking and data acquisition networks (the Space Network and the Near Earth Network), develops and maintains advanced space and Earth science data information systems, and develops satellite systems for the National Oceanic and Atmospheric Administration (NOAA).[62] Johnson Space Center (JSC) is the NASA center for human spaceflight training, research and flight control.[63] It is home to the United States Astronaut Corps and is responsible for training astronauts from the US and its international partners, and includes the Christopher C. Kraft Jr. Mission Control Center.[64] JSC also operates the White Sands Test Facility in Las Cruces, New Mexico to support rocket testing. View of JPL (left) and the Langley Research Center (right) Jet Propulsion Laboratory (JPL), located in the San Gabriel Valley area of Los Angeles County, C and builds and operates robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions.[65] It is also responsible for operating NASA's Deep Space Network (DSN). Langley Research Center (LaRC), located in Hampton, Virginia devotes two-thirds of its programs to aeronautics, and the rest to space. LaRC researchers use more than 40 wind tunnels to study improved aircraft and spacecraft safety, performance, and efficiency. The center was also home to early human spaceflight efforts including the team chronicled in the Hidden Figures story.[66] Aerial view of Kennedy Space Center showing VAB and Launch Complex 39 View of the SLS exiting the VAB at KSC (left) and of the MSFC test stands (right) Kennedy Space Center (KSC), located west of Cape Canaveral Space Force Station in Florida, has been the launch site for every United States human space flight since 1968. KSC also manages and operates uncrewed rocket launch facilities for America's civil space program from three pads at Cape Canaveral.[67] Marshall Space Flight Center (MSFC), located on the Redstone Arsenal near Huntsville, Alabama, is one of NASA's largest centers and is leading the development of the Space Launch System in support of the Artemis program. Marshall is NASA's lead center for International Space Station (ISS) design and assembly; payloads and related crew training; and was the lead for Space Shuttle propulsion and its external tank.[68] Stennis Space Center, originally the "Mississippi Test Facility", is located in Hancock County, Mississippi, on the banks of the Pearl River at the Mississippi–Louisiana border.[69] Commissioned in October 1961, it is currently used for rocket testing by over 30 local, state, national, international, private, and public companies and agencies.[70][71] It also contains the NASA Shared Services Center.[72] Past human spaceflight programs X-15 (1954–1968) Further information: North American X-15 X-15 in powered flight NASA inherited NACA's X-15 experimental rocket-powered hypersonic research aircraft, developed in conjunction with the US Air Force and Navy. Three planes were built starting in 1955. The X-15 was drop-launched from the wing of one of two NASA Boeing B-52 Stratofortresses, NB52A tail number 52-003, and NB52B, tail number 52-008 (known as the Balls 8). Release took place at an altitude of about 45,000 feet (14 km) and a speed of about 500 miles per hour (805 km/h).[73] Twelve pilots were selected for the program from the Air Force, Navy, and NACA. A total of 199 flights were made between June 1959 and December 1968, resulting in the official world record for the highest speed ever reached by a crewed powered aircraft (current as of 2014), and a maximum speed of Mach 6.72, 4,519 miles per hour (7,273 km/h).[74] The altitude record for X-15 was 354,200 feet (107.96 km).[75] Eight of the pilots were awarded Air Force astronaut wings for flying above 260,000 feet (80 km), and two flights by Joseph A. Walker exceeded 100 kilometers (330,000 ft), qualifying as spaceflight according to the International Aeronautical Federation. The X-15 program employed mechanical techniques used in the later crewed spaceflight programs, including reaction control system jets for controlling the orientation of a spacecraft, space suits, and horizon definition for navigation.[75] The reentry and landing data collected were valuable to NASA for designing the Space Shuttle.[76] Mercury (1958–1963) Further information: Project Mercury Mercury-patch-g.png L. Gordon Cooper, photographed by a slow-scan television camera aboard Faith 7 (May 16, 1963) In 1958, NASA formed an engineering group, the Space Task Group, to manage their human spaceflight programs under the direction of Robert Gilruth. Their earliest programs were conducted under the pressure of the Cold War competition between the US and the Soviet Union. NASA inherited the US Air Force's Man in Space Soonest program, which considered many crewed spacecraft designs ranging from rocket planes like the X-15, to small ballistic space capsules.[77] By 1958, the space plane concepts were eliminated in favor of the ballistic capsule,[78] and NASA renamed it Project Mercury. The first seven astronauts were selected among candidates from the Navy, Air Force and Marine test pilot programs. On May 5, 1961, astronaut Alan Shepard became the first American in space aboard a capsule he named Freedom 7, launched on a Redstone booster on a 15-minute ballistic (suborbital) flight.[79] John Glenn became the first American to be launched into orbit, on an Atlas launch vehicle on February 20, 1962, aboard Friendship 7.[80] Glenn completed three orbits, after which three more orbital flights were made, culminating in L. Gordon Cooper's 22-orbit flight Faith 7, May 15–16, 1963.[81] Katherine Johnson, Mary Jackson, and Dorothy Vaughan were three of the human computers doing calculations on trajectories during the Space Race.[82][83][84] Johnson was well known for doing trajectory calculations for John Glenn's mission in 1962, where she was running the same equations by hand that were being run on the computer.[82] Mercury's competition from the Soviet Union (USSR) was the single-pilot Vostok spacecraft. They sent the first man in space, cosmonaut Yuri Gagarin, into a single Earth orbit aboard Vostok 1 in April 1961, one month before Shepard's flight.[85] In August 1962, they achieved an almost four-day record flight with Andriyan Nikolayev aboard Vostok 3, and also conducted a concurrent Vostok 4 mission carrying Pavel Popovich.[86] Gemini (1961–1966) Further information: Project Gemini GeminiPatch.png Richard Gordon performs a spacewalk to attach a tether to the Agena Target Vehicle on Gemini 11, 1966. Based on studies to grow the Mercury spacecraft capabilities to long-duration flights, developing space rendezvous techniques, and precision Earth landing, Project Gemini was started as a two-man program in 1961 to overcome the Soviets' lead and to support the planned Apollo crewed lunar landing program, adding extravehicular activity (EVA) and rendezvous and docking to its objectives. The first crewed Gemini flight, Gemini 3, was flown by Gus Grissom and John Young on March 23, 1965.[87] Nine missions followed in 1965 and 1966, demonstrating an endurance mission of nearly fourteen days, rendezvous, docking, and practical EVA, and gathering medical data on the effects of weightlessness on humans.[88][89] Under the direction of Soviet Premier Nikita Khrushchev, the USSR competed with Gemini by converting their Vostok spacecraft into a two- or three-man Voskhod. They succeeded in launching two crewed flights before Gemini's first flight, achieving a three-cosmonaut flight in 1964 and the first EVA in 1965.[90] After this, the program was canceled, and Gemini caught up while spacecraft designer Sergei Korolev developed the Soyuz spacecraft, their answer to Apollo. Apollo (1960–1972) Further information: Apollo program Apollo program.svg Buzz Aldrin on the Moon, 1969 (photograph by Neil Armstrong) The U.S. public's perception of the Soviet lead in the Space Race (by putting the first man into space) motivated President John F. Kennedy[91] to ask the Congress on May 25, 1961, to commit the federal government to a program to land a man on the Moon by the end of the 1960s, which effectively launched the Apollo program.[92] Apollo was one of the most expensive American scientific programs ever. It cost more than $20 billion in 1960s dollars[93] or an estimated $236 billion in present-day US dollars.[94] (In comparison, the Manhattan Project cost roughly $30.1 billion, accounting for inflation.)[94][95] The Apollo program used the newly developed Saturn I and Saturn V rockets, which were far larger than the repurposed ICBMs of the previous Mercury and Gemini programs.[96] They were used to launch the Apollo spacecraft, consisting of the Command and Service Module (CSM) and the Lunar Module (LM). The CSM ferried astronauts from Earth to Moon orbit and back, while the Lunar Module would land them on the Moon itself.[note 1] The planned first crew of 3 astronauts were killed due to a fire during a 1967 preflight test for the Apollo 204 mission (later renamed Apollo 1).[97] The second crewed mission, Apollo 8, brought astronauts for the first time in a flight around the Moon in December 1968.[98] Shortly before, the Soviets had sent an uncrewed spacecraft around the Moon.[99] The next two missions (Apollo 9 and Apollo 10) practiced rendezvous and docking maneuvers required to conduct the Moon landing.[100][101] The Apollo 11 mission, launched in July 1969, landed the first humans on the Moon. Astronauts Neil Armstrong and Buzz Aldrin walked on the lunar surface, conducting experiments and sample collection, while Michael Collins orbited above in the CSM.[102] Six subsequent Apollo missions (12 through 17) were launched; five of them were successful, while one (Apollo 13) was aborted after an in-flight emergency nearly killed the astronauts. Throughout these seven Apollo spaceflights, twelve men walked on the Moon. These missions returned a wealth of scientific data and 381.7 kilograms (842 lb) of lunar samples. Topics covered by experiments performed included soil mechanics, meteoroids, seismology, heat flow, lunar ranging, magnetic fields, and solar wind.[103] The Moon landing marked the end of the space race; and as a gesture, Armstrong mentioned mankind when he stepped down on the Moon.[104] On July 3, 1969, the Soviets suffered a major setback on their Moon program when the rocket known as the N-1 had exploded in a fireball at its launch site at Baikonur in Kazakhstan, destroying one of two launch pads. Each of the first four launches of N-1 resulted in failure before the end of the first stage flight effectively denying the Soviet Union the capacity to deliver the systems required for a crewed lunar landing.[105] Apollo set major milestones in human spaceflight. It stands alone in sending crewed missions beyond low Earth orbit, and landing humans on another celestial body.[106] Apollo 8 was the first crewed spacecraft to orbit another celestial body, while Apollo 17 marked the last moonwalk and the last crewed mission beyond low Earth orbit. The program spurred advances in many areas of technology peripheral to rocketry and crewed spaceflight, including avionics, telecommunications, and computers. Apollo sparked interest in many fields of engineering and left many physical facilities and machines developed for the program as landmarks. Many objects and artifacts from the program are on display at various locations throughout the world, notably at the Smithsonian's Air and Space Museums. Skylab (1965–1979) Further information: Skylab Skylab Program Patch.png Skylab in 1974, seen from the departing Skylab 4 CSM Skylab was the United States' first and only independently built space station.[107] Conceived in 1965 as a workshop to be constructed in space from a spent Saturn IB upper stage, the 169,950 lb (77,088 kg) station was constructed on Earth and launched on May 14, 1973, atop the first two stages of a Saturn V, into a 235-nautical-mile (435 km) orbit inclined at 50° to the equator. Damaged during launch by the loss of its thermal protection and one electricity-generating solar panel, it was repaired to functionality by its first crew. It was occupied for a total of 171 days by 3 successive crews in 1973 and 1974.[107] It included a laboratory for studying the effects of microgravity, and a solar observatory.[107] NASA planned to have the in-development Space Shuttle dock with it, and elevate Skylab to a higher safe altitude, but the Shuttle was not ready for flight before Skylab's re-entry and demise on July 11, 1979.[108] To reduce cost, NASA modified one of the Saturn V rockets originally earmarked for a canceled Apollo mission to launch Skylab, which itself was a modified Saturn V fuel tank. Apollo spacecraft, launched on smaller Saturn IB rockets, were used for transporting astronauts to and from the station. Three crews, consisting of three men each, stayed aboard the station for periods of 28, 59, and 84 days. Skylab's habitable volume was 11,290 cubic feet (320 m3), which was 30.7 times bigger than that of the Apollo Command Module.[108] Space Transportation System (1969–1972) Further information: Space Transportation System In February 1969, President Richard Nixon appointed a space task group headed by Vice President Spiro Agnew to recommend human spaceflight projects beyond Apollo. The group responded in September with the Integrated Program Plan (IPP), intended to support space stations in Earth and lunar orbit, a lunar surface base, and a human Mars landing. These would be supported by replacing NASA's existing expendable launch systems with a reusable infrastructure including Earth orbit shuttles, space tugs, and a nuclear-powered trans-lunar and interplanetary shuttle. Despite the enthusiastic support of Agnew and NASA Administrator Thomas O. Paine, Nixon realized public enthusiasm, which translated into Congressional support, for the space program was waning as Apollo neared its climax, and vetoed most of these plans, except for the Earth orbital shuttle, and a deferred Earth space station.[109] Apollo–Soyuz (1972–1975) Further information: Apollo–Soyuz ASTP patch.png Soviet and American crews with spacecraft model, 1975 On May 24, 1972, US President Richard M. Nixon and Soviet Premier Alexei Kosygin signed an agreement calling for a joint crewed space mission, and declaring intent for all future international crewed spacecraft to be capable of docking with each other.[110] This authorized the Apollo–Soyuz Test Project (ASTP), involving the rendezvous and docking in Earth orbit of a surplus Apollo command and service module with a Soyuz spacecraft. The mission took place in July 1975. This was the last US human spaceflight until the first orbital flight of the Space Shuttle in April 1981.[111] The mission included both joint and separate scientific experiments and provided useful engineering experience for future joint US–Russian space flights, such as the Shuttle–Mir program[112] and the International Space Station. Space Shuttle (1972–2011) Further information: Space Shuttle program Shuttle Patch.svg Launch of Space Shuttle Discovery at the start of STS-120 The Space Shuttle was the only vehicle in the Space Transportation System to be developed, and became the major focus of NASA in the late 1970s and the 1980s. Originally planned as a frequently launchable, fully reusable vehicle, the design was changed to use an expendable external propellant tank to reduce development cost, and four Space Shuttle orbiters were built by 1985. The first to launch, Columbia, did so on April 12, 1981, the 20th anniversary of the first human spaceflight.[113] The Shuttle flew 135 missions and carried 355 astronauts from 16 countries, many on multiple trips. Its major components were a spaceplane orbiter with an external fuel tank and two solid-fuel launch rockets at its side. The external tank, which was bigger than the spacecraft itself, was the only major component that was not reused. The shuttle could orbit in altitudes of 185–643 km (115–400 miles)[114] and carry a maximum payload (to low orbit) of 24,400 kg (54,000 lb).[115] Missions could last from 5 to 17 days and crews could be from 2 to 8 astronauts.[114] On 20 missions (1983–1998) the Space Shuttle carried Spacelab, designed in cooperation with the European Space Agency (ESA). Spacelab was not designed for independent orbital flight, but remained in the Shuttle's cargo bay as the astronauts entered and left it through an airlock.[116] On June 18, 1983, Sally Ride became the first American woman in space, on board the Space Shuttle Challenger STS-7 mission.[117] Another famous series of missions were the launch and later successful repair of the Hubble Space Telescope in 1990 and 1993, respectively.[118] In 1995, Russian-American interaction resumed with the Shuttle–Mir missions (1995–1998). Once more an American vehicle docked with a Russian craft, this time a full-fledged space station. This cooperation has continued with Russia and the United States as two of the biggest partners in the largest space station built: the International Space Station (ISS).[119] The strength of their cooperation on this project was even more evident when NASA began relying on Russian launch vehicles to service the ISS during the two-year grounding of the shuttle fleet following the 2003 Space Shuttle Columbia disaster. The Shuttle fleet lost two orbiters and 14 astronauts in two disasters: Challenger in 1986, and Columbia in 2003.[120] While the 1986 loss was mitigated by building the Space Shuttle Endeavour from replacement parts, NASA did not build another orbiter to replace the second loss.[120] NASA's Space Shuttle program had 135 missions when the program ended with the successful landing of the Space Shuttle Atlantis at the Kennedy Space Center on July 21, 2011. The program spanned 30 years with 355 separate astronauts sent into space, many on multiple missions.[121] Constellation (2005–2010) Further information: Constellation program Constellation logo white.svg Artist's rendering of Altair lander on the Moon While the Space Shuttle program was still suspended after the loss of Columbia, President George W. Bush announced the Vision for Space Exploration including the retirement of the Space Shuttle after completing the International Space Station. The plan was enacted into law by the NASA Authorization Act of 2005 and directs NASA to develop and launch the Crew Exploration Vehicle (later called Orion) by 2010, return Americans to the Moon by 2020, land on Mars as feasible, repair the Hubble Space Telescope, and continue scientific investigation through robotic solar system exploration, human presence on the ISS, Earth observation, and astrophysics research. The crewed exploration goals prompted NASA's Constellation program.[122] On December 4, 2006, NASA announced it was planning a permanent Moon base.[123] The goal was to start building the Moon base by 2020, and by 2024, have a fully functional base that would allow for crew rotations and in-situ resource utilization. However, in 2009, the Augustine Committee found the program to be on an "unsustainable trajectory."[124] In February 2010, President Barack Obama's administration proposed eliminating public funds for it.[125] Journey to Mars (2010–2017) An artist's conception, from NASA, of an astronaut planting a US flag on Mars. A human mission to Mars has been discussed as a possible NASA mission since the 1960s. Concepts for how the first human landing site on Mars might evolve over the course of multiple human expeditions President Obama's plan was to develop American private spaceflight capabilities to get astronauts to the International Space Station, replace Russian Soyuz capsules, and use Orion capsules for ISS emergency escape purposes. During a speech at the Kennedy Space Center on April 15, 2010, Obama proposed a new heavy-lift vehicle (HLV) to replace the formerly planned Ares V.[126] In his speech, Obama called for a crewed mission to an asteroid as soon as 2025, and a crewed mission to Mars orbit by the mid-2030s.[126] The NASA Authorization Act of 2010 was passed by Congress and signed into law on October 11, 2010.[127] The act officially canceled the Constellation program.[127] The NASA Authorization Act of 2010 required a newly designed HLV be chosen within 90 days of its passing; the launch vehicle was given the name Space Launch System. The new law also required the construction of a beyond low earth orbit spacecraft.[128] The Orion spacecraft, which was being developed as part of the Constellation program, was chosen to fulfill this role.[129] The Space Launch System is planned to launch both Orion and other necessary hardware for missions beyond low Earth orbit.[130] The SLS is to be upgraded over time with more powerful versions. The initial capability of SLS is required to be able to lift 70 t (150,000 lb) (later 95 t or 209,000 lb) into LEO. It is then planned to be upgraded to 105 t (231,000 lb) and then eventually to 130 t (290,000 lb).[129][131] The Orion capsule first flew on Exploration Flight Test 1 (EFT-1), an uncrewed test flight that was launched on December 5, 2014, atop a Delta IV Heavy rocket.[131] NASA undertook a feasibility study in 2012 and developed the Asteroid Redirect Mission as an uncrewed mission to move a boulder-sized near-Earth asteroid (or boulder-sized chunk of a larger asteroid) into lunar orbit. The mission would demonstrate ion thruster technology and develop techniques that could be used for planetary defense against an asteroid collision, as well as a cargo transport to Mars in support of a future human mission. The Moon-orbiting boulder might then later be visited by astronauts. The Asteroid Redirect Mission was cancelled in 2017 as part of the FY2018 NASA budget, the first one under President Donald Trump.[132] Past robotic exploration programs Further information: List of uncrewed NASA missions NASA has conducted many uncrewed and robotic spaceflight programs throughout its history. Uncrewed robotic programs launched the first American artificial satellites into Earth orbit for scientific and communications purposes and sent scientific probes to explore the planets of the Solar System, starting with Venus and Mars, and including "grand tours" of the outer planets. More than 1,000 uncrewed missions have been designed to explore the Earth and the Solar System.[133] Early efforts The first US uncrewed satellite was Explorer 1, which started as an ABMA/JPL project during the early part of the Space Race. It was launched in January 1958, two months after Sputnik. At the creation of NASA, the Explorer project was transferred to the agency and still continues. Its missions have been focusing on the Earth and the Sun, measuring magnetic fields and the solar wind, among other aspects.[134] The Ranger missions developed technology to build and deliver robotic probes into orbit and to the vicinity of the Moon. Ranger 7 successfully returned images of the Moon in July 1964, followed by two more successful missions.[135] NASA also played a role in the development and delivery of early communications satellite technology to orbit. Syncom 3 was the first geostationary satellite. It was an experimental geosynchronous communications satellite placed over the equator at 180 degrees longitude in the Pacific Ocean. The satellite provided live television coverage of the 1964 Olympic games in Tokyo, Japan and conducted various communications tests. Operations were turned over to the Department of Defense on January 1, 1965; Syncom 3 was to prove useful in the DoD's Vietnam communications.[136] Programs like Syncom, Telstar, and Applications Technology Satellites (ATS) demonstrated the utility of communications satellites and delivered early telephonic and video satellite transmission.[137] Planetary exploration William H. Pickering, (center) JPL Director, President John F. Kennedy, (right). NASA Administrator James E. Webb (background) discussing the Mariner program, with a model presented. Study of Mercury, Venus, or Mars has been the goal of more than ten uncrewed NASA programs. The first was Mariner in the 1960s and 1970s, which made multiple visits to Venus and Mars and one to Mercury. Probes launched under the Mariner program were also the first to make a planetary flyby (Mariner 2), to take the first pictures from another planet (Mariner 4), the first planetary orbiter (Mariner 9), and the first to make a gravity assist maneuver (Mariner 10). This is a technique where the satellite takes advantage of the gravity and velocity of planets to reach its destination.[138] Magellan orbited Venus for four years in the early 1990s capturing radar images of the planet's surface.[139] MESSENGER orbited Mercury between 2011 and 2015 after a 6.5-year journey involving a complicated series of flybys of Venus and Mercury to reduce velocity sufficiently enough to enter Mercury orbit. MESSENGER became the first spacecraft to orbit Mercury and used its science payload to study Mercury's surface composition, geological history, internal magnetic field, and verified its polar deposits were dominantly water-ice.[140] From 1966 to 1968, the Lunar Orbiter and Surveyor missions provided higher quality photographs and other measurements to pave the way for the crewed Apollo missions to the Moon.[141] Clementine spent a couple of months mapping the Moon in 1994 before moving on to other mission objectives.[142] Lunar Prospector spent 19 months from 1998 mapping the Moon's surface composition and looking for polar ice.[143] The first successful landing on Mars was made by Viking 1 in 1976. Viking 2 followed two months later. Twenty years later the Sojourner rover was landed on Mars by Mars Pathfinder.[144] After Mars, Jupiter was first visited by Pioneer 10 in 1973. More than 20 years later Galileo sent a probe into the planet's atmosphere and became the first spacecraft to orbit the planet.[145] Pioneer 11 became the first spacecraft to visit Saturn in 1979, with Voyager 2 making the first (and so far, only) visits to Uranus and Neptune in 1986 and 1989, respectively. The first spacecraft to leave the Solar System was Pioneer 10 in 1983. For a time, it was the most distant spacecraft, but it has since been surpassed by both Voyager 1 and Voyager 2.[146] Pioneers 10 and 11 and both Voyager probes carry messages from the Earth to extraterrestrial life.[147][148] Communication can be difficult with deep space travel. For instance, it took about three hours for a radio signal to reach the New Horizons spacecraft when it was more than halfway to Pluto.[149] Contact with Pioneer 10 was lost in 2003. Both Voyager probes continue to operate as they explore the outer boundary between the Solar System and interstellar space.[150] NASA continued to support in situ exploration beyond the asteroid belt, including Pioneer and Voyager traverses into the unexplored trans-Pluto region, and gas giant orbiters Galileo (1989–2003) and Cassini (1997–2017) exploring the Jovian and Saturnian systems respectively. Heliophysics The missions below represent the robotic spacecraft that have been delivered and operated by NASA to study the heliosphere. The Helios A and Helios B missions were launched in the 1970s to study the Sun and were the first spacecraft to orbit inside of Mercury's orbit.[151] The Fast Auroral Snapshot Explorer (FAST) mission was launched in August 1996 becoming the second SMEX mission placed in orbit. It studied the auroral zones near each pole during its transits in a highly elliptical orbit.[152] The International Earth-Sun Explorer-3 (ISEE-3) mission was launched in 1978 and is the first spacecraft designed to operate at the Earth-Sun L1 libration point. It studied solar-terrestrial relationships at the outermost boundaries of the Earth's magnetosphere and the structure of the solar wind. The spacecraft was subsequently maneuvered out of the halo orbit and conducted a flyby of the Giacobini-Zinner comet in 1985 as the rechristened International Cometary Explorer (ICE).[153] Ulysses was launched in 1990 and slingshotted around Jupiter to put it in an orbit to travel over the poles of the Sun. It was designed study the space environment above and below the poles and delivered scientific data for about 19 years.[154] Additional spacecraft launched for studies of the heliosphere include: Cluster II, IMAGE, POLAR, Reuven Ramaty High Energy Solar Spectroscopic Imager, and the Van Allen Probes. Earth Science The Earth Sciences Division of the NASA Science Mission Directorate leads efforts to study the planet Earth. Spacecraft have been used to study Earth since the mid-1960s. Efforts included the Television Infrared Observation Satellite (TIROS) and Nimbus satellite systems of which there were many carrying weather research and forecasting from space from 1960 into the 2020s. Artist rendering of ICESat in orbit, 2003 The Combined Release and Radiation Effects Satellite (CRRES) was launched in 1990 on a three-year mission to investigate fields, plasmas, and energetic particles inside the Earth's magnetosphere.[155] The Upper Atmosphere Research Satellite (UARS) was launched in 1991 by STS-48 to study the Earth's atmosphere especially the protective ozone layer.[156] TOPEX/Poseidon was launched in 1992 and was the first significant oceanographic research satellite.[157] The Ice, Cloud, and land Elevation Satellite (ICESat) was launched in 2003, operated for seven years, and measured ice sheet mass balance, cloud and aerosol heights, and well as topography and vegetation characteristics.[158] Over a dozen past robotic missions have focused on the study of the Earth and its environment. Some of these additional missions include Aquarius, Earth Observing-1 (EO-1), Jason-1, Ocean Surface Topography Mission/Jason-2, and Radarsat-1 missions. Active programs Human spaceflight International Space Station (1993–present) Further information: International Space Station ISS emblem.png The International Space Station as seen from Space Shuttle Endeavour during STS-134 The International Space Station (ISS) combines NASA's Space Station Freedom project with the Soviet/Russian Mir-2 station, the European Columbus station, and the Japanese Kibō laboratory module.[159] NASA originally planned in the 1980s to develop Freedom alone, but US budget constraints led to the merger of these projects into a single multi-national program in 1993, managed by NASA, the Russian Federal Space Agency (RKA), the Japan Aerospace Exploration Agency (JAXA), the European Space Agency (ESA), and the Canadian Space Agency (CSA).[160][161] The station consists of pressurized modules, external trusses, solar arrays and other components, which were manufactured in various factories around the world, and have been launched by Russian Proton and Soyuz rockets, and the US Space Shuttles.[159] The on-orbit assembly began in 1998, the completion of the US Orbital Segment occurred in 2009 and the completion of the Russian Orbital Segment occurred in 2010, though there are some debates of whether new modules should be added in the segment. The ownership and use of the space station is established in intergovernmental treaties and agreements[162] which divide the station into two areas and allow Russia to retain full ownership of the Russian Orbital Segment (with the exception of Zarya),[163][164] with the US Orbital Segment allocated between the other international partners.[162] Long-duration missions to the ISS are referred to as ISS Expeditions. Expedition crew members typically spend approximately six months on the ISS.[165] The initial expedition crew size was three, temporarily decreased to two following the Columbia disaster. Since May 2009, expedition crew size has been six crew members.[166] Crew size is expected to be increased to seven, the number the ISS was designed for, once the Commercial Crew Program becomes operational.[167] The ISS has been continuously occupied for the past 22 years and 173 days, having exceeded the previous record held by Mir; and has been visited by astronauts and cosmonauts from 15 different nations.[168][169] The station can be seen from the Earth with the naked eye and, as of 2023, is the largest artificial satellite in Earth orbit with a mass and volume greater than that of any previous space station.[170] The Russian Soyuz and American Dragon spacecraft are used to send astronauts to and from the ISS. Several uncrewed cargo spacecraft provide service to the ISS; they are the Russian Progress spacecraft which has done so since 2000, the European Automated Transfer Vehicle (ATV) since 2008, the Japanese H-II Transfer Vehicle (HTV) since 2009, the (uncrewed) Dragon since 2012, and the American Cygnus spacecraft since 2013.[171][172] The Space Shuttle, before its retirement, was also used for cargo transfer and would often switch out expedition crew members, although it did not have the capability to remain docked for the duration of their stay. Between the retirement of the Shuttle in 2011 and the commencement of crewed Dragon flights in 2020, American astronauts exclusively used the Soyuz for crew transport to and from the ISS[173] The highest number of people occupying the ISS has been thirteen; this occurred three times during the late Shuttle ISS assembly missions.[174] The ISS program is expected to continue to 2030,[175] after which the space station will be retired and destroyed in a controlled de-orbit.[176] Commercial Resupply Services (2008–present) Further information: Commercial Resupply Services Dragon Cygnus Commercial Resupply Services missions approaching International Space Station Commercial Resupply Services (CRS) are a contract solution to deliver cargo and supplies to the International Space Station (ISS) on a commmercial basis.[177] NASA signed its first CRS contracts in 2008 and awarded $1.6 billion to SpaceX for twelve cargo Dragon and $1.9 billion to Orbital Sciences[note 2] for eight Cygnus flights, covering deliveries to 2016. Both companies evolved or created their launch vehicle products to support the solution (SpaceX with The Falcon 9 and Orbital with the Antares). SpaceX flew its first operational resupply mission (SpaceX CRS-1) in 2012.[178] Orbital Sciences followed in 2014 (Cygnus CRS Orb-1).[179] In 2015, NASA extended CRS-1 to twenty flights for SpaceX and twelve flights for Orbital ATK.[note 2][180][181] A second phase of contracts (known as CRS-2) was solicited in 2014; contracts were awarded in January 2016 to Orbital ATK[note 2] Cygnus, Sierra Nevada Corporation Dream Chaser, and SpaceX Dragon 2, for cargo transport flights beginning in 2019 and expected to last through 2024. In March 2022, NASA awarded an additional six CRS-2 missions each to both SpaceX and Northrop Grumman (formerly Orbital).[182] Northrop Grumman successfully delivered Cygnus NG-17 to the ISS in February 2022.[183] In July 2022, SpaceX launched its 25th CRS flight (SpaceX CRS-25) and successfully delivered its cargo to the ISS.[184] In late 2022, Sierra Nevada continued to assemble their Dream Chaser CRS solution; current estimates put its first launch in early 2023.[185] Commercial Crew Program (2011–present) Further information: Commercial Crew Program NASA Commercial Crew Program logo (cropped).svg The Crew Dragon (left) and Starliner (right) approaching the ISS on their respective missions The Commercial Crew Program (CCP) provides commercially operated crew transportation service to and from the International Space Station (ISS) under contract to NASA, conducting crew rotations between the expeditions of the International Space Station program. American space manufacturer SpaceX began providing service in 2020, using the Crew Dragon spacecraft, and NASA plans to add Boeing when its Boeing Starliner spacecraft becomes operational some time after 2022[needs update].[186] NASA has contracted for six operational missions from Boeing and fourteen from SpaceX, ensuring sufficient support for ISS through 2030.[187] The spacecraft are owned and operated by the vendor, and crew transportation is provided to NASA as a commercial service. Each mission sends up to four astronauts to the ISS, with an option for a fifth passenger available. Operational flights occur approximately once every six months for missions that last for approximately six months. A spacecraft remains docked to the ISS during its mission, and missions usually overlap by at least a few days. Between the retirement of the Space Shuttle in 2011 and the first operational CCP mission in 2020, NASA relied on the Soyuz program to transport its astronauts to the ISS. A Crew Dragon spacecraft is launched to space atop a Falcon 9 Block 5 launch vehicle and the capsule returns to Earth via splashdown in the ocean near Florida. The program's first operational mission, SpaceX Crew-1, launched on 16 November 2020.[188] Boeing Starliner operational flights will now commence after its final test flight which was launched atop an Atlas V N22 launch vehicle. Instead of a splashdown, a Starliner capsule returns on land with airbags at one of four designated sites in the western United States.[189] Artemis (2017–present) Further information: Artemis program An arrowhead combined with a depiction of a trans-lunar injection trajectory forms an "A", with an "Artemis" wordmark printed underneath SLS with Orion rolling to Launch Complex 39B for tests, Mar 2022 Since 2017, NASA's crewed spaceflight program has been the Artemis program, which involves the help of US commercial spaceflight companies and international partners such as ESA, JAXA, and CSA.[190] The goal of this program is to land "the first woman and the next man" on the lunar south pole region by 2024. Artemis would be the first step towards the long-term goal of establishing a sustainable presence on the Moon, laying the foundation for companies to build a lunar economy, and eventually sending humans to Mars. The Orion Crew Exploration Vehicle was held over from the canceled Constellation program for Artemis. Artemis 1 was the uncrewed initial launch of Space Launch System (SLS) that would also send an Orion spacecraft on a Distant Retrograde Orbit.[191] NASA's next major space initiative is to be the construction of the Lunar Gateway, a small space station in lunar orbit.[192] This space station will be designed primarily for non-continuous human habitation. The first tentative steps of returning to crewed lunar missions will be Artemis 2, which is to include the Orion crew module, propelled by the SLS, and is to launch in 2024.[190] This mission is to be a 10-day mission planned to briefly place a crew of four into a Lunar flyby.[131] The construction of the Gateway would begin with the proposed Artemis 3, which is planned to deliver a crew of four to Lunar orbit along with the first modules of the Gateway. This mission would last for up to 30 days. NASA plans to build full scale deep space habitats such as the Lunar Gateway and the Nautilus-X as part of its Next Space Technologies for Exploration Partnerships (NextSTEP) program.[193] In 2017, NASA was directed by the congressional NASA Transition Authorization Act of 2017 to get humans to Mars-orbit (or to the Martian surface) by the 2030s.[194][195] In support of the Artemis missions, NASA has been funding private companies to land robotic probes on the lunar surface in a program known as the Commercial Lunar Payload Services. As of March 2022, NASA has awarded contracts for robotic lunar probes to companies such as Intuitive Machines, Firefly Space Systems, and Astrobotic.[196] On April 16, 2021, NASA announced they had selected the SpaceX Lunar Starship as its Human Landing System. The agency's Space Launch System rocket will launch four astronauts aboard the Orion spacecraft for their multi-day journey to lunar orbit where they will transfer to SpaceX's Starship for the final leg of their journey to the surface of the Moon.[197] In November 2021, it was announced that the goal of landing astronauts on the Moon by 2024 had slipped to no earlier than 2025 due to numerous factors. Artemis 1 launched on November 16, 2022 and returned to Earth safely on December 11, 2022. As of June 2022, NASA plans to launch Artemis 2 in May 2024 and Artemis 3 in December 2025.[198][199] Additional Artemis missions, Artemis 4 and Artemis 5, are planned to launch after 2025.[200] Commercial LEO Development (2021–present) The Commercial Low Earth Orbit Destinations program is an initiative by NASA to support work on commercial space stations that the agency hopes to have in place by the end of the current decade to replace the "International Space Station". The three selected companies are: Blue Origin (et al.) with their Orbital Reef station concept, Nanoracks (et al.) with their Starlab Space Station concept, and Northrop Grumman with a station concept based on the HALO-module for the Gateway station.[201] Robotic exploration Further information: List of NASA missions and List of uncrewed NASA missions Video of many of the uncrewed missions used to explore the outer reaches of space NASA has conducted many uncrewed and robotic spaceflight programs throughout its history. More than 1,000 uncrewed missions have been designed to explore the Earth and the Solar System.[133] Mission selection process NASA executes a mission development framework to plan, select, develop, and operate robotic missions. This framework defines cost, schedule and technical risk parameters to enable competitive selection of missions involving mission candidates that have been developed by principal investigators and their teams from across NASA, the broader U.S. Government research and development stakeholders, and industry. The mission development construct is defined by four umbrella programs. Explorer program Further information: Explorers Program The Explorer program derives its origin from the earliest days of the U.S. Space program. In current form, the program consists of three classes of systems - Small Explorers (SMEX), Medium Explorers (MIDEX), and University-Class Explorers (UNEX) missions. The NASA Explorer program office provides frequent flight opportunities for moderate cost innovative solutions from the heliophysics and astrophysics science areas. The Small Explorer missions are required to limit cost to NASA to below $150M (2022 dollars). Medium class explorer missions have typically involved NASA cost caps of $350M. The Explorer program office is based at NASA Goddard Space Flight Center.[202] Discovery program Further information: Discovery Program The NASA Discovery program develops and delivers robotic spacecraft solutions in the planetary science domain. Discovery enables scientists and engineers to assemble a team to deliver a solution against a defined set of objectives and competitively bid that solution against other candidate programs. Cost caps vary but recent mission selection processes were accomplished using a $500M cost cap to NASA. The Planetary Mission Program Office is based at the NASA Marshall Space Flight Center and manages both the Discovery and New Frontiers missions. The office is part of the Science Mission Directorate.[203] NASA Administrator Bill Nelson announced on June 2, 2021, that the DAVINCI+ and VERITAS missions were selected to launch to Venus in the late 2020s, having beat out competing proposals for missions to Jupiter's volcanic moon Io and Neptune's large moon Triton that were also selected as Discovery program finalists in early 2020. Each mission has an estimated cost of $500 million, with launches expected between 2028 and 2030. Launch contracts will be awarded later in each mission's development.[204] New Frontiers program Further information: New Frontiers program The New Frontiers program focuses on specific Solar System exploration goals identified as top priorities by the planetary science community. Primary objectives include Solar System exploration employing medium class spacecraft missions to conduct high-science-return investigations. New Frontiers builds on the development approach employed by the Discovery program but provides for higher cost caps and schedule durations than are available with Discovery. Cost caps vary by opportunity; recent missions have been awarded based on a defined cap of $1 Billion. The higher cost cap and projected longer mission durations result in a lower frequency of new opportunities for the program - typically one every several years. OSIRIS-REx and New Horizons are examples of New Frontiers missions.[205] NASA has determined that the next opportunity to propose for the fifth round of New Frontiers missions will occur no later than the fall of 2024. Missions in NASA's New Frontiers Program tackle specific Solar System exploration goals identified as top priorities by the planetary science community. Exploring the Solar System with medium-class spacecraft missions that conduct high-science-return investigations is NASA's strategy to further understand the Solar System.[206] Large strategic missions Further information: Large strategic science missions Large strategic missions (formerly called Flagship missions) are strategic missions that are typically developed and managed by large teams that may span several NASA centers. The individual missions become the program as opposed to being part of a larger effort (see Discovery, New Frontiers, etc.). The James Webb Space Telescope is a strategic mission that was developed over a period of more than 20 years. Strategic missions are developed on an ad-hoc basis as program objectives and priorities are established. Missions like Voyager, had they been developed today, would have been strategic missions. Three of the Great Observatories were strategic missions (the Chandra X-ray Observatory, Compton, and the Hubble Space Telescope). Europa Clipper is the next large strategic mission in development by NASA. Planetary science missions NASA continues to play a material in exploration of the Solar System as it has for decades. Ongoing missions have current science objectives with respect to more than five extraterrestrial bodies within the Solar System – Moon (Lunar Reconnaissance Orbiter), Mars (Perseverance rover), Jupiter (Juno), asteroid Bennu (OSIRIS-REx), and Kuiper Belt Objects (New Horizons). The Juno extended mission will make multiple flybys of the Jovian moon Io in 2023 and 2024 after flybys of Ganymede in 2021 and Europa in 2022. Voyager 1 and Voyager 2 continue to provide science data back to Earth while continuing on their outward journeys into interstellar space. On November 26, 2011, NASA's Mars Science Laboratory mission was successfully launched for Mars. The Curiosity rover successfully landed on Mars on August 6, 2012, and subsequently began its search for evidence of past or present life on Mars.[207][208][209] In September 2014, NASA's MAVEN spacecraft, which is part of the Mars Scout Program, successfully entered Mars orbit and, as of October 2022, continues its study of the atmosphere of Mars.[210][211] NASA's ongoing Mars investigations include in-depth surveys of Mars by the Perseverance rover and InSight). NASA's Europa Clipper, planned for launch in October 2024, will study the Galilean moon Europa through a series of flybys while in orbit around Jupiter. Dragonfly will send a mobile robotic rotorcraft to Saturn's biggest moon, Titan.[212] As of May 2021, Dragonfly is scheduled for launch in June 2027.[213][214] Astrophysics missions NASA astrophysics spacecraft fleet, credit NASA GSFC, 2022 The NASA Science Mission Directorate Astrophysics division manages the agency's astrophysics science portfolio. NASA has invested significant resources in the development, delivery, and operations of various forms of space telescopes. These telescopes have provided the means to study the cosmos over a large range of the electromagnetic spectrum.[215] The Great Observatories that were launched in the 1980s and 1990s have provided a wealth of observations for study by physicists across the planent. The first of them, the Hubble Space Telescope, was delivered to orbit in 1990 and continues to function, in part due to prior servicing missions performed by the Space Shuttle.[216][217] The other remaining active great observatory include the Chandra X-ray Observatory (CXO), launched by STS-93 in July 1999 and is now in a 64-hour elliptical orbit studying X-ray sources that are not readily viewable from terrestrial observatories.[218] Chandra X-ray Observatory (rendering), 2015 The Imaging X-ray Polarimetry Explorer (IXPE) is a space observatory designed to improve the understanding of X-ray production in objects such as neutron stars and pulsar wind nebulae, as well as stellar and supermassive black holes.[219] IXPE launched in December 2021 and is an international collaboration between NASA and the Italian Space Agency (ASI). It is part of the NASA Small Explorers program (SMEX) which designs low-cost spacecraft to study heliophysics and astrophysics.[220] The Neil Gehrels Swift Observatory was launched in November 2004 and is Gamma-ray burst observatory that also monitors the afterglow in X-ray, and UV/Visible light at the location of a burst.[221] The mission was developed in a joint partnership between Goddard Space Flight Center (GSFC) and an international consortium from the United States, United Kingdom, and Italy. Pennsylvania State University operates the mission as part of NASA's Medium Explorer program (MIDEX).[222] The Fermi Gamma-ray Space Telescope (FGST) is another gamma-ray focused space observatory that was launched to low Earth orbit in June 2008 and is being used to perform gamma-ray astronomy observations.[223] In addition to NASA, the mission involves the United States Department of Energy, and government agencies in France, Germany, Italy, Japan, and Sweden.[224] The James Webb Space Telescope (JWST), launched in December 2021 on an Ariane 5 rocket, operates in a halo orbit circling the Sun-Earth L2 point.[225][226][227] JWST's high sensitivity in the infrared spectrum and its imaging resolution will allow it to view more distant, faint, or older objects than its predecessors, including Hubble.[228] Earth Sciences Program missions (1965–present) Further information: NASA Earth Science Schematic of NASA Earth Science Division operating satellite missions as of February 2015 NASA Earth Science is a large, umbrella program comprising a range of terrestrial and space-based collection systems in order to better understand the Earth system and its response to natural and human-caused changes. Numerous systems have been developed and fielded over several decades to provide improved prediction for weather, climate, and other changes in the natural environment. Several of the current operating spacecraft programs include: Aqua,[229] Aura,[230] Orbiting Carbon Observatory 2 (OCO-2),[231] Gravity Recovery and Climate Experiment Follow-on (GRACE FO),[232] and Ice, Cloud, and land Elevation Satellite 2 (ICESat-2).[233] In addition to systems already in orbit, NASA is designing a new set of Earth Observing Systems to study, assess, and generate responses for climate change, natural hazards, forest fires, and real-time agricultural processes.[234] The GOES-T satellite (designated GOES-18 after launch) joined the fleet of U.S. geostationary weather monitoring satellites in March 2022.[235] NASA also maintains the Earth Science Data Systems (ESDS) program to oversee the life cycle of NASA's Earth science data — from acquisition through processing and distribution. The primary goal of ESDS is to maximize the scientific return from NASA's missions and experiments for research and applied scientists, decision makers, and society at large.[236] The Earth Science program is managed by the Earth Science Division of the NASA Science Mission Directorate. Space operations architecture NASA invests in various ground and space-based infrastructures to support its science and exploration mandate. The agency maintains access to suborbital and orbital space launch capabilities and sustains ground station solutions to support its evolving fleet of spacecraft and remote systems. Deep Space Network (1963–present) Further information: NASA Deep Space Network The NASA Deep Space Network (DSN) serves as the primary ground station solution for NASA's interplanetary spacecraft and select Earth-orbiting missions.[237] The system employs ground station complexes near Barstow California in the United States, in Spain near Madrid, and in Australia near Canberra. The placement of these ground stations approximately 120 degrees apart around the planet provides the ability for communications to spacecraft throughout the Solar System even as the Earth rotates about its axis on a daily basis. The system is controlled at a 24x7 operations center at JPL in Pasadena California which manages recurring communications linkages with up to 40 spacecraft.[238] The system is managed by the Jet Propulsion Laboratory (JPL).[237] Near Space Network (1983–present) Further information: Near Earth Network and Tracking and Data Relay Satellite System Near Earth Network Ground Stations, 2021 The Near Space Network (NSN) provides telemetry, commanding, ground-based tracking, data and communications services to a wide range of customers with satellites in low earth orbit (LEO), geosynchronous orbit (GEO), highly elliptical orbits (HEO), and lunar orbits. The NSN accumulates ground station and antenna assets from the Near-Earth Network and the Tracking and Data Relay Satellite System (TDRS) which operates in geosynchronous orbit providing continuous real-time coverage for launch vehicles and low earth orbit NASA missions.[239] The NSN consists of 19 ground stations worldwide operated by the US Government and by contractors including Kongsberg Satellite Services (KSAT), Swedish Space Corporation (SSC), and South African National Space Agency (SANSA).[240] The ground network averages between 120 and 150 spacecraft contacts a day with TDRS engaging with systems on a near-continuous basis as needed; the system is managed and operated by the Goddard Space Flight Center.[241] Sounding Rocket Program (1959–present) Further information: NASA Sounding Rocket Program NASA sounding rocket launch from the Wallops Flight Facility The NASA Sounding Rocket Program (NSRP) is located at the Wallops Flight Facility and provides launch capability, payload development and integration, and field operations support to execute suborbital missions.[242] The program has been in operation since 1959 and is managed by the Goddard Space Flight Center using a combined US Government and contractor team.[243] The NSRP team conducts approximately 20 missions per year from both Wallops and other launch locations worldwide to allow scientists to collect data "where it occurs". The program supports the strategic vision of the Science Mission Directorate collecting important scientific data for earth science, heliophysics, and astrophysics programs.[242] In June 2022, NASA conducted its first rocket launch from a commercial spaceport outside the US. It launched a Black Brant IX from the Arnhem Space Centre in Australia.[244] Launch Services Program (1990–present) Further information: NASA Launch Services Program Launch Services Program logo.svg The NASA Launch Services Program (LSP) is responsible for procurement of launch services for NASA uncrewed missions and oversight of launch integration and launch preparation activity, providing added quality and mission assurance to meet program objectives.[245] Since 1990, NASA has purchased expendable launch vehicle launch services directly from commercial providers, whenever possible, for its scientific and applications missions. Expendable launch vehicles can accommodate all types of orbit inclinations and altitudes and are ideal vehicles for launching Earth-orbit and interplanetary missions. LSP operates from Kennedy Space Center and falls under the NASA Space Operations Mission Directorate (SOMD).[246][247] Aeronautics Research Further information: NASA research and Aeronautics Research Mission Directorate The Aeronautics Research Mission Directorate (ARMD) is one of five mission directorates within NASA, the other four being the Exploration Systems Development Mission Directorate, the Space Operations Mission Directorate, the Science Mission Directorate, and the Space Technology Mission Directorate.[248] The ARMD is responsible for NASA's aeronautical research, which benefits the commercial, military, and general aviation sectors. ARMD performs its aeronautics research at four NASA facilities: Ames Research Center and Armstrong Flight Research Center in California, Glenn Research Center in Ohio, and Langley Research Center in Virginia.[249] NASA X-57 Maxwell aircraft (2016–present) Further information: NASA X-57 Maxwell The NASA X-57 Maxwell is an experimental aircraft being developed by NASA to demonstrate the technologies required to deliver a highly efficient all-electric aircraft.[250] The primary goal of the program is to develop and deliver all-electric technology solutions that can also achieve airworthiness certification with regulators. The program involves development of the system in several phases, or modifications, to incrementally grow the capability and operability of the system. The initial configuration of the aircraft has now completed ground testing as it approaches its first flights. In mid-2022, the X-57 was scheduled to fly before the end of the year.[251] The development team includes staff from the NASA Armstrong, Glenn, and Langley centers along with number of industry partners from the United States and Italy.[252] Next Generation Air Transportation System (2007–present) Further information: Next Generation Air Transportation System NASA is collaborating with the Federal Aviation Administration and industry stakeholders to modernize the United States National Airspace System (NAS). Efforts began in 2007 with a goal to deliver major modernization components by 2025.[253] The modernization effort intends to increase the safety, efficiency, capacity, access, flexibility, predictability, and resilience of the NAS while reducing the environmental impact of aviation.[254] The Aviation Systems Division of NASA Ames operates the joint NASA/FAA North Texas Research Station. The station supports all phases of NextGen research, from concept development to prototype system field evaluation. This facility has already transitioned advanced NextGen concepts and technologies to use through technology transfers to the FAA.[253] NASA contributions also include development of advanced automation concepts and tools that provide air traffic controllers, pilots, and other airspace users with more accurate real-time information about the nation's traffic flow, weather, and routing. Ames' advanced airspace modeling and simulation tools have been used extensively to model the flow of air traffic flow across the U.S., and to evaluate new concepts in airspace design, traffic flow management, and optimization.[255] Technology research For technologies funded or otherwise supported by NASA, see NASA spinoff technologies. Nuclear in-space power and propulsion (ongoing) NASA has made use of technologies such as the multi-mission radioisotope thermoelectric generator (MMRTG), which is a type of radioisotope thermoelectric generator used to power spacecraft.[256] Shortages of the required plutonium-238 have curtailed deep space missions since the turn of the millennium.[257] An example of a spacecraft that was not developed because of a shortage of this material was New Horizons 2.[257] In July 2021, NASA announced contract awards for development of nuclear thermal propulsion reactors. Three contractors will develop individual designs over 12 months for later evaluation by NASA and the U.S. Department of Energy.[258] NASA's space nuclear technologies portfolio are led and funded by its Space Technology Mission Directorate. Other initiatives Free Space Optics. NASA contracted a third party to study the probability of using Free Space Optics (FSO) to communicate with Optical (laser) Stations on the Ground (OGS) called laser-com RF networks for satellite communications.[259] Water Extraction from Lunar Soil. On July 29, 2020, NASA requested American universities to propose new technologies for extracting water from the lunar soil and developing power systems. The idea will help the space agency conduct sustainable exploration of the Moon.[260] Human Spaceflight Research (2005–present) Human Research Program logo.png SpaceX Crew-4 astronaut Samantha Cristoforetti operating the rHEALTH ONE on the ISS to address key health risks for space travel NASA's Human Research Program (HRP) is designed to study the effects of space on human health and also to provide countermeasures and technologies for human space exploration. The medical effects of space exploration are reasonably limited in low Earth orbit or in travel to the Moon. Travel to Mars, however, is significantly longer and deeper into space and significant medical issues can result. This includes bone loss, radiation exposure, vision changes, circadian rhythm disturbances, heart remodeling, and immune alterations. In order to study and diagnose these ill-effects, HRP has been tasked with identifying or developing small portable instrumentation with low mass, volume, and power to monitor the health of astronauts.[261] To achieve this aim, on May 13, 2022, NASA and SpaceX Crew-4 astronauts successfully tested its rHEALTH ONE universal biomedical analyzer for its ability to identify and analyzer biomarkers, cells, microorganisms, and proteins in a spaceflight environment.[262] Planetary Defense (2016–present) Further information: Planetary Defense Coordination Office and Near Earth Objects Planetary Defense Coordination Office seal.png NASA established the Planetary Defense Coordination Office (PDCO) in 2016 to catalog and track potentially hazardous near-Earth objects (NEO), such as asteroids and comets and develop potential responses and defenses against these threats.[263] The PDCO is chartered to provide timely and accurate information to the government and the public on close approaches by Potentially hazardous objects (PHOs) and any potential for impact. The office functions within the Science Mission Directorate Planetary Science division.[264] The PDCO augmented prior cooperative actions between the United States, the European Union, and other nations which had been scanning the sky for NEOs since 1998 in an effort called Spaceguard.[265] Near Earth object detection (1998–present) From the 1990s NASA has run many NEO detection programs from Earth bases observatories, greatly increasing the number of objects that have been detected. However, many asteroids are very dark and the ones that are near the Sun are much harder to detect from Earth-based telescopes which observe at night, and thus face away from the Sun. NEOs inside Earth orbit only reflect a part of light also rather than potentially a "full Moon" when they are behind the Earth and fully lit by the Sun. In 1998, the United States Congress gave NASA a mandate to detect 90% of near-Earth asteroids over 1 km (0.62 mi) diameter (that threaten global devastation) by 2008.[266] This initial mandate was met by 2011.[267] In 2005, the original USA Spaceguard mandate was extended by the George E. Brown, Jr. Near-Earth Object Survey Act, which calls for NASA to detect 90% of NEOs with diameters of 140 m (460 ft) or greater, by 2020 (compare to the 20-meter Chelyabinsk meteor that hit Russia in 2013).[268] As of January 2020, it is estimated that less than half of these have been found, but objects of this size hit the Earth only about once in 2,000 years.[269] In January 2020, NASA officials estimated it would take 30 years to find all objects meeting the 140 m (460 ft) size criteria, more than twice the timeframe that was built into the 2005 mandate.[270] In June 2021, NASA authorized the development of the NEO Surveyor spacecraft to reduce that projected duration to achieve the mandate down to 10 years.[271][272] Involvement in current robotic missions NASA has incorporated planetary defense objectives into several ongoing missions. In 1999, NASA visited 433 Eros with the NEAR Shoemaker spacecraft which entered its orbit in 2000, closely imaging the asteroid with various instruments at that time.[273] NEAR Shoemaker became the first spacecraft to successfully orbit and land on an asteroid, improving our understanding of these bodies and demonstrating our capacity to study them in greater detail.[274] OSIRIS-REx used its suite of instruments to transmit radio tracking signals and capture optical images of Bennu during its study of the asteroid that will help NASA scientists determine its precise position in the solar system and its exact orbital path. As Bennu has the potential for recurring approaches to the Earth-Moon system in the next 100–200 years, the precision gained from OSIRIS-REx will enable scientists to better predict the future gravitational interactions between Bennu and our planet and resultant changes in Bennu's onward flight path.[275][276] The WISE/NEOWISE mission was launched by NASA JPL in 2009 as an infrared-wavelength astronomical space telescope. In 2013, NASA repurposed it as the NEOWISE mission to find potentially hazardous near-Earth asteroids and comets; its mission has been extended into 2023.[277][278] NASA and Johns Hopkins Applied Physics Laboratory (JHAPL) jointly developed the first planetary defense purpose-built satellite, the Double Asteroid Redirection Test (DART) to test possible planetary defense concepts.[279] DART was launched in November 2021 by a SpaceX Falcon 9 from California on a trajectory designed to impact the Dimorphos asteroid. Scientists were seeking to determine whether an impact could alter the subsequent path of the asteroid; a concept that could be applied to future planetary defense.[280] On September 26, 2022, DART hit its target. In the weeks following impact, NASA declared DART a success, confirming it had shortened Dimorphos' orbital period around Didymos by about 32 minutes, surpassing the pre-defined success threshold of 73 seconds.[281][282] NEO Surveyor, formerly called the Near-Earth Object Camera (NEOCam) mission, is a space-based infrared telescope under development to survey the Solar System for potentially hazardous asteroids.[283] The spacecraft is scheduled to launch in 2026. Study of Unidentified Aerial Phenomena (2022–present) In June 2022, the head of the NASA Science Mission Directorate, Thomas Zurbuchen, confirmed that NASA would join the hunt for Unidentified Flying Objects (UFOs)/Unidentified Aerial Phenomena (UAPs).[284] At a speech before the National Academies of Science, Engineering and Medicine, Zurbuchen said the space agency would bring a scientific perspective to efforts already underway by the Pentagon and intelligence agencies to make sense of dozens of such sightings. He said it was "high-risk, high-impact" research that the space agency should not shy away from, even if it is a controversial field of study.[285] Collaboration NASA Advisory Council In response to the Apollo 1 accident, which killed three astronauts in 1967, Congress directed NASA to form an Aerospace Safety Advisory Panel (ASAP) to advise the NASA Administrator on safety issues and hazards in NASA's air and space programs. In the aftermath of the Shuttle Columbia disaster, Congress required that the ASAP submit an annual report to the NASA Administrator and to Congress.[286] By 1971, NASA had also established the Space Program Advisory Council and the Research and Technology Advisory Council to provide the administrator with advisory committee support. In 1977, the latter two were combined to form the NASA Advisory Council (NAC).[287] The NASA Authorization Act of 2014 reaffirmed the importance of ASAP. National Oceanic and Atmospheric Administration (NOAA) Further information: National Oceanic and Atmospheric Administration NOAA logo mobile.svg NASA and NOAA have cooperated for decades on the development, delivery and operation of polar and geosynchronous weather satellites.[288] The relationship typically involves NASA developing the space systems, launch solutions, and ground control technology for the satellites and NOAA operating the systems and delivering weather forecasting products to users. Multiple generations of NOAA Polar orbiting platforms have operated to provide detailed imaging of weather from low altitude.[289] Geostationary Operational Environmental Satellites (GOES) provide near-real-time coverage of the western hemisphere to ensure accurate and timely understanding of developing weather phenomenon.[290] United States Space Force Further information: United States Space Force United States Space Force logo.svg The United States Space Force (USSF) is the space service branch of the United States Armed Forces, while the National Aeronautics and Space Administration (NASA) is an independent agency of the United States government responsible for civil spaceflight. NASA and the Space Force's predecessors in the Air Force have a long-standing cooperative relationship, with the Space Force supporting NASA launches out of Kennedy Space Center, Cape Canaveral Space Force Station, and Vandenberg Space Force Base, to include range support and rescue operations from Task Force 45.[291] NASA and the Space Force also partner on matters such as defending Earth from asteroids.[292] Space Force members can be NASA astronauts, with Colonel Michael S. Hopkins, the commander of SpaceX Crew-1, commissioned into the Space Force from the International Space Station on December 18, 2020.[293][294][295] In September 2020, the Space Force and NASA signed a memorandum of understanding formally acknowledging the joint role of both agencies. This new memorandum replaced a similar document signed in 2006 between NASA and Air Force Space Command.[296][297] U.S. Geological Survey Further information: United States Geological Survey and Landsat 9 USGS logo green.svg The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program.[298] On July 23, 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat 1 in 1975.[299] The most recent satellite in the series, Landsat 9, was launched on September 27, 2021.[300] The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education, and can be viewed through the U.S. Geological Survey (USGS) "EarthExplorer" website. The collaboration between NASA and USGS involves NASA designing and delivering the space system (satellite) solution, launching the satellite into orbit with the USGS operating the system once in orbit.[298] As of October 2022, nine satellites have been built with eight of them successfully operating in orbit. European Space Agency (ESA) Further information: European Space Agency European Space Agency logo.svg NASA collaborates with the European Space Agency on a wide range of scientific and exploration requirements.[301] From participation with the Space Shuttle (the Spacelab missions) to major roles on the Artemis program (the Orion Service Module), ESA and NASA have supported the science and exploration missions of each agency. There are NASA payloads on ESA spacecraft and ESA payloads on NASA spacecraft. The agencies have developed joint missions in areas including heliophysics (e.g. Solar Orbiter)[302] and astronomy (Hubble Space Telescope, James Webb Space Telescope).[303] Under the Artemis Gateway partnership, ESA will contribute habitation and refueling modules, along with enhanced lunar communications, to the Gateway.[304][305] NASA and ESA continue to advance cooperation in relation to Earth Science including climate change with agreements to cooperate on various missions including the Sentinel-6 series of spacecraft[306] Japan Aerospace Exploration Agency (JAXA) Further information: Japan Aerospace Exploration Agency Jaxa logo.svg NASA and the Japan Aerospace Exploration Agency (JAXA) cooperate on a range of space projects. JAXA is a direct participant in the Artemis program, including the Lunar Gateway effort. JAXA's planned contributions to Gateway include I-Hab's environmental control and life support system, batteries, thermal control, and imagery components, which will be integrated into the module by the European Space Agency (ESA) prior to launch. These capabilities are critical for sustained Gateway operations during crewed and uncrewed time periods.[307][308] JAXA and NASA have collaborated on numerous satellite programs, especially in areas of Earth science. NASA has contributed to JAXA satellites and vice versa. Japanese instruments are flying on NASA's Terra and Aqua satellites, and NASA sensors have flown on previous Japanese Earth-observation missions. The NASA-JAXA Global Precipitation Measurement mission was launched in 2014 and includes both NASA- and JAXA-supplied sensors on a NASA satellite launched on a JAXA rocket. The mission provides the frequent, accurate measurements of rainfall over the entire globe for use by scientists and weather forecasters.[309] Roscosmos Further information: Roscosmos Roscosmos logo ru.svg NASA and Roscosmos have cooperated on the development and operation of the International Space Station since September 1993.[310] The agencies have used launch systems from both countries to deliver station elements to orbit. Astronauts and Cosmonauts jointly maintain various elements of the station. Both countries provide access to the station via launch systems noting Russia's unique role as the sole provider of delivery of crew and cargo upon retirement of the space shuttle in 2011 and prior to commencement of NASA COTS and crew flights. In July 2022, NASA and Roscosmos signed a deal to share space station flights enabling crew from each country to ride on the systems provided by the other.[311] Current geopolitical conditions in late 2022 make it unlikely that cooperation will be extended to other programs such as Artemis or lunar exploration.[312] Indian Space Research Organisation Further information: Indian Space Research Organisation Indian Space Research Organisation Logo.svg In September 2014, NASA and Indian Space Research Organisation (ISRO) signed a partnership to collaborate on and launch a joint radar mission, the NASA-ISO Synthetic Aperature Radar (NISAR) mission. The mission is targeted to launch in 2024. NASA will provide the mission's L-band synthetic aperture radar, a high-rate communication subsystem for science data, GPS receivers, a solid-state recorder and payload data subsystem. ISRO provides the spacecraft bus, the S-band radar, the launch vehicle and associated launch services.[313][314] Artemis Accords Further information: Artemis Accords The Artemis Accords have been established to define a framework for cooperating in the peaceful exploration and exploitation of the Moon, Mars, asteroids, and comets. The Accords were drafted by NASA and the U.S. State Department and are executed as a series of bilateral agreements between the United States and the participating countries.[315][316] As of September 2022, 21 countries have signed the accords. They are Australia, Bahrain, Brazil, Canada, Colombia, France, Israel, Italy, Japan, the Republic of Korea, Luxembourg, Mexico, New Zealand, Poland, Romania, the Kingdom of Saudi Arabia, Singapore, Ukraine, the United Arab Emirates, the United Kingdom, and the United States.[317][318] China National Space Administration Further information: Wolf Amendment and China National Space Administration The Wolf Amendment was passed by the U.S. Congress into law in 2011 and prevents NASA from engaging in direct, bilateral cooperation with the Chinese government and China-affiliated organizations such as the China National Space Administration without the explicit authorization from Congress and the Federal Bureau of Investigation. The law has been renewed annually since by inclusion in annual appropriations bills.[319] Sustainability Environmental impact The exhaust gases produced by rocket propulsion systems, both in Earth's atmosphere and in space, can adversely affect the Earth's environment. Some hypergolic rocket propellants, such as hydrazine, are highly toxic prior to combustion, but decompose into less toxic compounds after burning. Rockets using hydrocarbon fuels, such as kerosene, release carbon dioxide and soot in their exhaust.[320] However, carbon dioxide emissions are insignificant compared to those from other sources; on average, the United States consumed 803 million US gal (3.0 million m3) of liquid fuels per day in 2014, while a single Falcon 9 rocket first stage burns around 25,000 US gallons (95 m3) of kerosene fuel per launch.[321][322] Even if a Falcon 9 were launched every single day, it would only represent 0.006% of liquid fuel consumption (and carbon dioxide emissions) for that day. Additionally, the exhaust from LOx- and LH2- fueled engines, like the SSME, is almost entirely water vapor.[323] NASA addressed environmental concerns with its canceled Constellation program in accordance with the National Environmental Policy Act in 2011.[324] In contrast, ion engines use harmless noble gases like xenon for propulsion.[325][326] An example of NASA's environmental efforts is the NASA Sustainability Base. Additionally, the Exploration Sciences Building was awarded the LEED Gold rating in 2010.[327] On May 8, 2003, the Environmental Protection Agency recognized NASA as the first federal agency to directly use landfill gas to produce energy at one of its facilities—the Goddard Space Flight Center, Greenbelt, Maryland.[328] In 2018, NASA along with other companies including Sensor Coating Systems, Pratt & Whitney, Monitor Coating and UTRC launched the project CAUTION (CoAtings for Ultra High Temperature detectION). This project aims to enhance the temperature range of the Thermal History Coating up to 1,500 °C (2,730 °F) and beyond. The final goal of this project is improving the safety of jet engines as well as increasing efficiency and reducing CO2 emissions.[329] Climate change NASA also researches and publishes on climate change.[330] Its statements concur with the global scientific consensus that the global climate is warming.[331] Bob Walker, who has advised US President Donald Trump on space issues, has advocated that NASA should focus on space exploration and that its climate study operations should be transferred to other agencies such as NOAA. Former NASA atmospheric scientist J. Marshall Shepherd countered that Earth science study was built into NASA's mission at its creation in the 1958 National Aeronautics and Space Act.[332] NASA won the 2020 Webby People's Voice Award for Green in the category Web.[333] STEM Initiatives Further information: STEM Educational Launch of Nanosatellites (ELaNa). Since 2011, the ELaNa program has provided opportunities for NASA to work with university teams to test emerging technologies and commercial-off-the-shelf solutions by providing launch opportunities for developed CubeSats using NASA procured launch opportunities.[334] By example, two NASA-sponsored CubeSats launched in June 2022 on a Virgin Orbit LauncherOne vehicle as the ELaNa 39 mission.[335] Cubes in Space. NASA started an annual competition in 2014 named "Cubes in Space".[336] It is jointly organized by NASA and the global education company I Doodle Learning, with the objective of teaching school students aged 11–18 to design and build scientific experiments to be launched into space on a NASA rocket or balloon. On June 21, 2017, the world's smallest satellite, KalamSAT, was launched.[337] Use of the metric system US law requires the International System of Units to be used in all US Government programs, "except where impractical".[338] In 1969, Apollo 11 landed on the Moon using a mix of United States customary units and metric units. In the 1980s, NASA started the transition towards the metric system, but was still using both systems in the 1990s.[339][340] On September 23, 1999, a mixup between NASA's use of SI units and Lockheed Martin Space's use of US units resulted in the loss of the Mars Climate Orbiter.[341] In August 2007, NASA stated that all future missions and explorations of the Moon would be done entirely using the SI system. This was done to improve cooperation with space agencies of other countries that already use the metric system.[342] As of 2007, NASA is predominantly working with SI units, but some projects still use US units, and some, including the International Space Station, use a mix of both.[343] Media presence NASA TV Further information: NASA TV Approaching 40 years of service, the NASA TV channel airs content ranging from live coverage of crewed missions to video coverage of significant milestones for operating robotic spacecraft (e.g., rover landings on Mars for example) and domestic and international launches.[344] The channel is delivered by NASA and is broadcast by satellite and over the Internet. The system initially started to capture archival footage of important space events for NASA managers and engineers and expanded as public interest grew. The Apollo 8 Christmas Eve broadcast while in orbit around the Moon was received by more than a billion people.[345] NASA's video transmission of the Apollo 11 Moon landing was awarded a primetime Emmy in commemoration of the 40th anniversary of the landing.[346] The channel is a product of the U.S. Government and is widely available across many television and Internet platforms.[347] NASAcast NASAcast is the official audio and video podcast of the NASA website. Created in late 2005, the podcast service contains the latest audio and video features from the NASA web site, including NASA TV's This Week at NASA and educational materials produced by NASA. Additional NASA podcasts, such as Science@NASA, are also featured and give subscribers an in-depth look at content by subject matter.[348] NASA EDGE NASA EDGE broadcasting live from White Sands Missile Range in 2010 NASA EDGE is a video podcast which explores different missions, technologies and projects developed by NASA. The program was released by NASA on March 18, 2007, and, as of August 2020, there have been 200 vodcasts produced. It is a public outreach vodcast sponsored by NASA's Exploration Systems Mission Directorate and based out of the Exploration and Space Operations Directorate at Langley Research Center in Hampton, Virginia. The NASA EDGE team takes an insiders look at current projects and technologies from NASA facilities around the United States, and it is depicted through personal interviews, on-scene broadcasts, computer animations, and personal interviews with top scientists and engineers at NASA.[note 3] The show explores the contributions NASA has made to society as well as the progress of current projects in materials and space exploration. NASA EDGE vodcasts can be downloaded from the NASA website and from iTunes. In its first year of production, the show was downloaded over 450,000 times. As of February 2010, the average download rate is more than 420,000 per month, with over one million downloads in December 2009 and January 2010.[350] NASA and the NASA EDGE have also developed interactive programs designed to complement the vodcast. The Lunar Electric Rover App allows users to drive a simulated Lunar Electric Rover between objectives, and it provides information about and images of the vehicle.[351] The NASA EDGE Widget provides a graphical user interface for accessing NASA EDGE vodcasts, image galleries, and the program's Twitter feed, as well as a live NASA news feed.[352] Astronomy Picture of the Day This section is an excerpt from Astronomy Picture of the Day.[edit] Astronomy Picture of the Day (APOD) is a website provided by NASA and Michigan Technological University (MTU). According to the website, "Each day a different image or photograph of our universe is featured, along with a brief explanation written by a professional astronomer."[353] The photograph does not necessarily correspond to a celestial event on the exact day that it is displayed, and images are sometimes repeated.[354] However, the pictures and descriptions often relate to current events in astronomy and space exploration. The text has several hyperlinks to more pictures and websites for more information. The images are either visible spectrum photographs, images taken at non-visible wavelengths and displayed in false color, video footage, animations, artist's conceptions, or micrographs that relate to space or cosmology. Past images are stored in the APOD Archive, with the first image appearing on June 16, 1995.[355] This initiative has received support from NASA, the National Science Foundation, and MTU. The images are sometimes authored by people or organizations outside NASA, and therefore APOD images are often copyrighted, unlike many other NASA image galleries.[356] When the APOD website was created, it received a total of 14 page views on its first day. As of 2012, the APOD website has received over a billion image views throughout its lifetime.[357] APOD is also translated into 21 languages daily." (wikipedia.org) "A puzzle is a game, problem, or toy that tests a person's ingenuity or knowledge. In a puzzle, the solver is expected to put pieces together (or take them apart) in a logical way, in order to arrive at the correct or fun solution of the puzzle. There are different genres of puzzles, such as crossword puzzles, word-search puzzles, number puzzles, relational puzzles, and logic puzzles. The academic study of puzzles is called enigmatology. Puzzles are often created to be a form of entertainment but they can also arise from serious mathematical or logical problems. In such cases, their solution may be a significant contribution to mathematical research.[1] Etymology The Oxford English Dictionary dates the word puzzle (as a verb) to the end of the 16th century. Its earliest use documented in the OED was in a book titled The Voyage of Robert Dudley...to the West Indies, 1594–95, narrated by Capt. Wyatt, by himself, and by Abram Kendall, master (published circa 1595). The word later came to be used as a noun, first as an abstract noun meaning 'the state or condition of being puzzled', and later developing the meaning of 'a perplexing problem'. The OED's earliest clear citation in the sense of 'a toy that tests the player's ingenuity' is from Sir Walter Scott's 1814 novel Waverley, referring to a toy known as a "reel in a bottle".[2] The etymology of the verb puzzle is described by OED as "unknown"; unproven hypotheses regarding its origin include an Old English verb puslian meaning 'pick out', and a derivation of the verb pose.[3] Genres Various puzzles Simple puzzle made of three pieces Puzzles can be categorized as:     Lateral thinking puzzles, also called "situation puzzles"     Mathematical puzzles include the missing square puzzle and many impossible puzzles — puzzles which have no solution, such as the Seven Bridges of Königsberg, the three cups problem, and three utilities problem         Sangaku (Japanese temple tablets with geometry puzzles)     A chess problem is a puzzle that uses chess pieces on a chess board. Examples are the knight's tour and the eight queens puzzle.     Mechanical puzzles or dexterity puzzles such as the Rubik's Cube and Soma cube can be stimulating toys for children or recreational activities for adults.         combination puzzles like Peg solitaire         construction puzzles such as stick puzzles         disentanglement puzzles,         folding puzzles         jigsaw puzzles. Puzz 3D is a three-dimensional variant of this type.         lock puzzles         A puzzle box can be used to hide something — jewelry, for instance.         sliding puzzles (also called sliding tile puzzles) such as the 15 Puzzle and Sokoban         tiling puzzles like Tangram         Tower of Hanoi     Metapuzzles are puzzles which unite elements of other puzzles.     Paper-and-pencil puzzles such as Uncle Art's Funland, connect the dots, and nonograms         Also the logic puzzles published by Nikoli: Sudoku, Slitherlink, Kakuro, Fillomino, Hashiwokakero, Heyawake, Hitori, Light Up, Masyu, Number Link, Nurikabe, Ripple Effect, Shikaku, and Kuromasu.     Spot the difference     Tour puzzles like a maze     Word puzzles, including anagrams, ciphers, crossword puzzles, Hangman (game), and word search puzzles. Tabletop and digital word puzzles include Bananagrams, Boggle, Bonza, Dabble, Letterpress (video game), Perquackey, Puzzlage, Quiddler, Ruzzle, Scrabble, Upwords, WordSpot, and Words with Friends. Wheel of Fortune (U.S. game show) is a game show centered on a word puzzle.     Puzzle video games         Tile-matching video game         Puzzle-platformer         Adventure game         Hidden object game         Minesweeper Puzzle solving     This section possibly contains original research. Please improve it by verifying the claims made and adding inline citations. Statements consisting only of original research should be removed. (November 2018) (Learn how and when to remove this template message) Solutions of puzzles often require the recognition of patterns and the adherence to a particular kind of ordering. People with a high level of inductive reasoning aptitude may be better at solving such puzzles than others. But puzzles based upon inquiry and discovery may be solved more easily by those with good deduction skills. Deductive reasoning improves with practice. Mathematical puzzles often involve BODMAS. BODMAS is an acronym and it stands for Bracket, Of, Division, Multiplication, Addition and Subtraction. In certain regions, PEMDAS (Parentheses, Exponents, Multiplication, Division, Addition and Subtraction) is the synonym of BODMAS. It explains the order of operations to solve an expression. Some mathematical puzzles require Top to Bottom convention to avoid the ambiguity in the order of operations. It is an elegantly simple idea that relies, as sudoku does, on the requirement that numbers appear only once starting from top to bottom as coming along.[4] Puzzle makers Puzzle makers are people who make puzzles. In general terms of occupation, a puzzler is someone who composes and/or solves puzzles. Some notable creators of puzzles are:     Ernő Rubik     Sam Loyd     Henry Dudeney     Boris Kordemsky     David J. Bodycombe     Will Shortz     Oskar van Deventer     Lloyd King     Martin Gardner     Raymond Smullyan History of jigsaw and other puzzles Main article: Jigsaw puzzle Jigsaw puzzles are perhaps the most popular form of puzzle. Jigsaw puzzles were invented around 1760, when John Spilsbury, a British engraver and cartographer, mounted a map on a sheet of wood, which he then sawed around the outline of each individual country on the map. He then used the resulting pieces as an aid for the teaching of geography.[5] After becoming popular among the public, this kind of teaching aid remained the primary use of jigsaw puzzles until about 1820.[6] The largest puzzle (40,320 pieces) is made by German game company Ravensburger.[7] The smallest puzzle ever made was created at LaserZentrum Hannover. It is only five square millimeters, the size of a sand grain. The puzzles that were first documented are riddles. In Europe, Greek mythology produced riddles like the riddle of the Sphinx. Many riddles were produced during the Middle Ages, as well.[8] By the early 20th century, magazines and newspapers found that they could increase their readership by publishing puzzle contests, beginning with crosswords and in modern days sudoku. Organizations and events There are organizations and events that cater to puzzle enthusiasts, such as:     Nob Yoshigahara Puzzle Design Competition     World Puzzle Championship     National Puzzlers' League     Puzzlehunts such as the Maze of Games     World Cube Association" (wikipedia.org) "A jigsaw puzzle is a tiling puzzle that requires the assembly of often irregularly shaped interlocking and mosaiced pieces, each of which typically has a portion of a picture. When assembled, the puzzle pieces produce a complete picture. In the 18th century, jigsaw puzzles were created by painting a picture on a flat, rectangular piece of wood, then cutting it into small pieces. Despite the name, a jigsaw was never used. John Spilsbury, a London cartographer and engraver, is credited with commercialising jigsaw puzzles around 1760. His design took world maps, and cut out the individual nations in order for them to be reassembled by students as a geographical teaching aid.[1] They have since come to be made primarily of interlocking cardboard pieces, incorporating a variety of images & designs. Typical images on jigsaw puzzles include scenes from nature, buildings, and repetitive designs—castles and mountains are common, as well as other traditional subjects. However, any picture can be used. Artisan puzzle-makers and companies using technologies for one-off and small print-run puzzles utilize a wide range of subject matter, including optical illusions, unusual art, and personal photographs. In addition to traditional flat, two-dimensional puzzles, three-dimensional puzzles have entered large-scale production, including spherical puzzles and architectural recreations. A range of jigsaw puzzle accessories, including boards, cases, frames, and roll-up mats, have become available to assist jigsaw puzzle enthusiasts. While most assembled puzzles are disassembled for reuse, they can also be attached to a backing with adhesive and displayed as art. History John Spilsbury's "Europe divided into its kingdoms, etc." (1766). He created the jigsaw puzzle for educational purposes, and called them "Dissected Maps".[2][3] John Spilsbury is believed to have produced the first jigsaw puzzle around 1760, using a marquetry saw.[1] Early puzzles, known as dissections, were produced by mounting maps on sheets of hardwood and cutting along national boundaries, creating a puzzle useful for teaching geography.[1] Royal governess Lady Charlotte Finch used such "dissected maps" to teach the children of King George III and Queen Charlotte[4][5] Cardboard jigsaw puzzles appeared in the late 1800s, but were slow to replace wooden ones because manufacturers felt that cardboard puzzles would be perceived as low-quality, and because profit margins on wooden jigsaws were larger.[1] British printed puzzle from 1874. The name "jigsaw" came to be associated with the puzzle around 1880 when fretsaws became the tool of choice for cutting the shapes. Since fretsaws are distinct from jigsaws, the name appears to be a misnomer.[1] Wooden jigsaw pieces, cut by hand Jigsaw puzzles soared in popularity during the Great Depression, as they provided a cheap, long-lasting, recyclable form of entertainment.[1][6] It was around this time that jigsaws evolved to become more complex and appealing to adults.[1] They were also given away in product promotions and used in advertising, with customers completing an image of the promoted product.[1][6] Sales of wooden puzzles fell after World War II as improved wages led to price increases, while improvements in manufacturing processes made paperboard jigsaws more attractive.[6] Demand for jigsaw puzzles saw a surge, comparable to that of the Great Depression, during the COVID-19 pandemic's stay-at-home orders.[7][8] Modern construction Paperboard jigsaw pieces Most modern jigsaw puzzles are made of paperboard as they are easier and cheaper to mass-produce. An enlarged photograph or printed reproduction of a painting or other two-dimensional artwork is glued to cardboard, which is then fed into a press. The press forces a set of hardened steel blades of the desired pattern, called a puzzle die, through the board until fully cut. The puzzle die is a flat board, often made from plywood, with slots cut or burned in the same shape as the knives that are used. The knives are set into the slots and covered in a compressible material, typically foam rubber, which ejects the cut puzzle pieces. The cutting process is similar to making shaped cookies with a cookie cutter. However, the forces involved are tremendously greater: A typical 1000-piece puzzle requires upwards of 700 tons of force to push the die through the board. Beginning in the 1930s, jigsaw puzzles were cut using large hydraulic presses that now cost hundreds of thousands of dollars. The precise cuts gave a snug fit, but the cost limited jigsaw puzzle production to large corporations. Recent roller-press methods achieve the same results at a lower cost.[citation needed] New technology has also enabled laser-cutting of wooden or acrylic jigsaw puzzles. The advantage is that the puzzle can be custom-cut to any size or shape, with any number or average size of pieces. Many museums have laser-cut acrylic puzzles made of some of their art so visiting children can assemble puzzles of the images on display. Acrylic pieces are very durable, waterproof, and can withstand continued use without the image degrading. Also, because the print and cut patterns are computer-based, missing pieces can easily be remade. By the early 1960s, Tower Press was the world's largest jigsaw puzzle maker; it was acquired by Waddingtons in 1969.[9] Numerous smaller-scale puzzle makers work in artisanal styles, handcrafting and handcutting their creations.[10][11][12][13] Variations Jigsaw puzzle software allowing rotation of pieces A three-dimensional puzzle composed of several two-dimensional puzzles stacked on top of one another A puzzle without a picture Jigsaw puzzles come in a variety of sizes. Among those marketed to adults, 300-, 500- and 750-piece puzzles are considered "smaller". More sophisticated, but still common, puzzles come in sizes of 1,000, 1,500, 2,000, 3,000, 4,000, 5,000, 6,000, 7,500, 8,000, 9,000, 13,200, 18,000, 24,000, 32,000 and 40,000 pieces. Jigsaw puzzles geared towards children typically have many fewer pieces and are typically much larger. For very young children, puzzles with as few as 4 to 9 large pieces (so as not to be a choking hazard) are standard. They are usually made of wood or plastic for durability and can be cleaned without damage. The most common layout for a thousand-piece puzzle is 38 pieces by 27 pieces, for an actual total of 1,026 pieces. Most 500-piece puzzles are 27 pieces by 19 pieces. A few puzzles are double-sided so they can be solved from either side—adding complexity, as the enthusiast must determine if they are looking at the right side of each piece. "Family puzzles" of 100–550 pieces use an assortment of small, medium and large pieces, with each size going in one direction or towards the middle of the puzzle. This allows a family of different skill levels and hand sizes to work on the puzzle together. Companies like Springbok, Cobble Hill, Ceaco, Buffalo Games and Suns Out make this type of specialty puzzle. Ravensburger, on the other hand, formerly made this type of puzzle from 2000 until 2008. There are also three-dimensional jigsaw puzzles. Many are made of wood or styrofoam and require the puzzle to be solved in a particular order, as some pieces will not fit if others are already in place. One type of 3-D jigsaw puzzle is a puzzle globe, often made of plastic. Like 2-D puzzles, the assembled pieces form a single layer, but the final form is three-dimensional. Most globe puzzles have designs representing spherical shapes such as the Earth, the Moon, and historical globes of the Earth. Also common are puzzle boxes, simple three-dimensional puzzles with a small drawer or box in the center for storage. Jigsaw puzzles can vary significantly in price depending on their complexity, number of pieces, and brand. In the US, children's puzzles can start around $5, while larger ones can be closer to $50. The most expensive puzzle to date was sold for $US27,000 in 2005 at a charity auction for The Golden Retriever Foundation.[14] Several word-puzzle games use pieces similar to those in jigsaw puzzles. Examples include Alfa-Lek, Jigsaw Words, Nab-It!, Puzzlage, Typ-Dom, Word Jigsaw, and Yottsugo.[15][citation needed] Puzzle pieces A "whimsy" piece in a wooden jigsaw puzzle A 3D jigsaw puzzle Many puzzles are termed "fully interlocking", which means that adjacent pieces are connected so that they stay attached when one is turned. Sometimes the connection is tight enough to pick up a solved part by holding one piece. Some fully interlocking puzzles have pieces of a similar shape, with rounded tabs (interjambs) on opposite ends and corresponding indentations—called blanks—on the other two sides to receive the tabs. Other fully interlocking puzzles may have tabs and blanks variously arranged on each piece; but they usually have four sides, and the numbers of tabs and blanks thus add up to four. Uniformly shaped fully interlocking puzzles, sometimes called "Japanese Style", are the most difficult because the differences in the pieces' shapes are most subtle.[citation needed] Most jigsaw puzzles are square, rectangular or round, with edge pieces with one straight or smoothly curved side, plus four corner pieces (if the puzzle is square or rectangular). However, some puzzles have edge, and corner pieces cut like the rest, with no straight sides, making it more challenging to identify them. Other puzzles utilize more complex edge pieces to form unique shapes when assembled, such as profiles of animals. The pieces of spherical jigsaw, like immersive panorama jigsaw, can be triangular-shaped, according to the rules of tessellation of the geoid primitive. Designer Yuu Asaka created "Jigsaw Puzzle 29". Instead of four corner pieces, it has five. The puzzle is made from pale blue acrylic without a picture.[16] It was awarded the Jury Honorable Mention of 2018 Puzzle Design Competition.[17] Because many puzzlers had solved it easily, he created "Jigsaw Puzzle 19" which composed only with corner pieces as revenge.[18] It was made with transparent green acrylic pieces without a picture.[19] Calculating the number of edge pieces Jigsaw puzzlers often want to know in advance how many border pieces they are looking for to verify they have found all of them. Puzzle sizes are typically listed on commercially distributed puzzles but usually include the total number of pieces in the puzzle and do not list the count of edge or interior pieces. These 88 border pieces include 4 corners, 17 pieces between corners on the short sides, and 25 between corners on the long sides. Common puzzle dimensions:     1000 piece puzzle: 1026 pieces, 126 border pieces (38x27)[20] World records Largest commercially available jigsaw puzzles Pieces     Name of puzzle     Company     Year     Size [cm]     Area [m2] 60,000     What A Wonderful World     Dowdle Folk Art     2022     883 × 243     21.46 54,000     Travel around Art     Grafika     2020     864 × 204     17.63 52,110     (No title: collage of animals)     MartinPuzzle     2018     696 × 202     14.06 51,300     27 Wonders from Around the World     Kodak     2019     869 × 191     16.60 48,000     Around the World     Grafika     2017     768 × 204     15.67 42,000     La vuelta al Mundo     Educa Borras     2017     749 × 157     11.76 40,320     Making Mickey's Magic     Ravensburger     2018     680 × 192     13.06 40,320     Memorable Disney Moments     Ravensburger     2016     680 × 192     13.06 33,600     Wild Life     Educa Borras     2014     570 × 157     8.95 32,000     New York City Window     Ravensburger     2014     544 × 192     10.45 32,000     Double Retrospect     Ravensburger     2010     544 × 192     10.45 24,000     Life, The greatest puzzle     Educa Borras     2007     428 × 157     6.72 Largest-sized jigsaw puzzles The world's largest-sized jigsaw puzzle measured 5,428.8 m2 (58,435 sq ft) with 21,600 pieces, each measuring a Guinness World Records maximum size of 50 cm by 50 cm. It was assembled on 3 November 2002 by 777 people at the former Kai Tak Airport in Hong Kong.[21] Largest jigsaw puzzle – most pieces The Guinness record of CYM Group in 2011 with 551,232 pieces The jigsaw with the greatest number of pieces had 551,232 pieces and measured 14.85 × 23.20 m (48 ft 8.64 in × 76 ft 1.38 in). It was assembled on 25 September 2011 at Phú Thọ Indoor Stadium in Ho Chi Minh City, Vietnam, by students of the University of Economics, Ho Chi Minh City. It is listed by the Guinness World Records for the "Largest Jigsaw Puzzle – most pieces", but as the intact jigsaw had been divided into 3,132 sections, each containing 176 pieces, which were reassembled and then connected, the claim is controversial.[22][23] Society The logo of Wikipedia is a globe made out of jigsaw pieces. The incomplete sphere symbolizes the room to add new knowledge.[citation needed] In the logo of the Colombian Office of the Attorney General appears a jigsaw puzzle piece in the foreground. They named it "The Key Piece": "The piece of a puzzle is the proper symbol to visually represent the Office of the Attorney General because it includes the concepts of search, solution and answers that the entity pursues through the investigative activity."[24] Art and entertainment The central antagonist in the Saw film franchise is nicknamed Jigsaw,[25] due to his practice of cutting the shape of a puzzle piece from the remains of his victims. In the 1933 Laurel and Hardy short Me and My Pal, several characters attempt to complete a large jigsaw puzzle.[26] Lost in Translation is a poem about a child putting together a jigsaw puzzle, as well as an interpretive puzzle itself. Life: A User's Manual, Georges Perec's most famous novel, tells as pieces of a puzzle a story about a jigsaw puzzle maker. Jigsaw Puzzle (song), sometimes spelled "Jig-Saw Puzzle" is a song by the rock and roll band The Rolling Stones, featured on their 1968 album Beggars Banquet. In ‘‘Citizen Kane‘’ Susan Alexander Kane (Dorothy Comingore) is reduced to spending her days completing jigsaws after the failure of her operatic career. After Kane’s death when ‘’Xanadu’’ is emptied, hundreds of jigsaw puzzles are discovered in the cellar. Rhett And Link Do A Rainy Day Jigsaw Puzzle is a short video by self-described “internetainers” (portmanteau of “Internet” and “entertainers”) Rhett & Link which portrays the frustration of discovering a puzzle piece is missing. Mental health According to the Alzheimer Society of Canada, doing jigsaw puzzles is one of many activities that can help keep the brain active and may reduce the risk of Alzheimer's disease.[27] An "autism awareness" ribbon, featuring red, blue, and yellow jigsaw pieces Jigsaw puzzle pieces were first used as a symbol for autism in 1963 by the United Kingdom's National Autistic Society.[28] The organization chose jigsaw pieces for their logo to represent the "puzzling" nature of autism and the inability to "fit in" due to social differences, and also because jigsaw pieces were recognizable and otherwise unused.[29] Puzzle pieces have since been incorporated into the logos and promotional materials of many organizations, including the Autism Society of America and Autism Speaks. Proponents of the autism rights movement oppose the jigsaw puzzle iconography, stating that metaphors such as "puzzling" and "incomplete" are harmful to autistic people. Critics of the puzzle piece symbol instead advocate for a gold-colored or red infinity symbol representing diversity.[30] In 2017, the journal Autism concluded that the use of the jigsaw puzzle evoked negative public perception towards autistic individuals. They removed the puzzle piece from their cover in February 2018." (wikipedia.org)
  • Condition: New
  • Brand: Discovery
  • Year: 2020
  • Number of Pieces: 26 - 99 Pieces
  • Color: Multi-Color
  • Theme: Space
  • Features: Complete, Never Worked, Lenticular, STEM Activity
  • Material: Cardboard
  • Country/Region of Manufacture: China

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