Space station

The modular International Space Station, the largest object ever assembled in Earth orbit

A space station, also known as an orbital station or an orbital space station, is a spacecraft capable of supporting a human crew in orbit for an extended period of time that lacks major propulsion or landing systems. 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. As of 2019, one fully operational and permanently inhabited space station is in low Earth orbit: the International Space Station (ISS), which is used to study the effects of long-term space flight on the human body as well as to provide a location to conduct a greater number and length of scientific studies than is possible on other space vehicles. China, India, Russia, and the U.S., as well as Bigelow Aerospace and Axiom Space, are all planning other stations for the coming decades.

History

Rotating wheel space station. Wernher von Braun 1952 concept

The first mention of anything resembling a space station occurred in Edward Everett Hale's 1869 "The Brick Moon".[1] 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.[2] 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.[1] 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.[3] 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.[2]

During the latter half of the 20th century, the Soviet Union developed and launched the world's first space station, Salyut 1.[4] 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 a considerable part of the ISS space station orbiting today. Each crew member stays aboard the station for weeks or months, but rarely more than a year. 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. As of 2016, 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.[5]

Early monolithic stations (1971–1986)

The U.S. Skylab station of the 1970s

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.[4]

The first space station was Salyut 1, which was launched by the Soviet Union on April 19, 1971. The earlier 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.[6]

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.[7] 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 utilized. 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.[6]

Mir (1986–2001)

Earth and the Mir station

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.[8]

Modules are still being developed based on the design and capabilities of Mir.

Tiangong program (2011–2019)

China's first space laboratory, Tiangong-1 was launched in September 2011.[9] 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, the crewed Shenzhou 10 in 2013. A second space laboratory Tiangong-2 was launched in September 2016, while a plan for Tiangong-3 was merged with Tiangong-2.[10]

In May 2017, China informed the United Nations Office for Outer Space Affairs that Tiangong-1's altitude was decaying and that it would soon reenter the atmosphere and break up.[10] The reentry was projected to occur in late March or early April 2018.[11] 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.[12][13][14][15][16]

In July 2019 the China Manned Space Engineering Office announced that it was planning to deorbit Tiangong-2 in the near future, but no specific date was given.[17] The station subsequently made a controlled reentry on 19 July and burned up over the South Pacific Ocean.[18]

Other Languages
العربية: محطة فضاء
azərbaycanca: Kosmik stansiya
dansk: Rumstation
Deutsch: Raumstation
Esperanto: Kosmostacio
français: Station spatiale
贛語: 太空站
한국어: 우주정거장
հայերեն: Ուղեծրակայան
Bahasa Indonesia: Stasiun luar angkasa
íslenska: Geimstöð
עברית: תחנת חלל
Kiswahili: Kituo cha Anga
Lëtzebuergesch: Raumstatioun
lietuvių: Kosminė stotis
magyar: Űrállomás
македонски: Вселенска станица
Bahasa Melayu: Stesen angkasa
Mirandés: Staçon spacial
Nederlands: Ruimtestation
Nordfriisk: Rümstasjoon
norsk: Romstasjon
norsk nynorsk: Romstasjon
português: Estação espacial
Seeltersk: Ruumstation
Simple English: Space station
slovenčina: Kozmická stanica
slovenščina: Vesoljska postaja
српски / srpski: Свемирска станица
srpskohrvatski / српскохрватски: Svemirska stanica
svenska: Rymdstation
татарча/tatarça: Orbital' stantsiä
Türkçe: Uzay istasyonu
Tiếng Việt: Trạm không gian
吴语: 空间站
粵語: 太空站
中文: 空间站