A space station (or orbital station) is a spacecraft which remains in orbit and hosts humans for extended periods of time. It is therefore an artificial satellite featuring habitation facilities. The purpose of maintaining a space station varies depending on the program. Most often space stations have been research stations, but they have also served military or commercial uses, such as hosting space tourists. Space stations have been hosting the only continuous presence of humans in space. The first space station was Salyut 1 (1971), which hosted the first crew of the ill-fated Soyuz 11. Consecutively space stations have been operated since Skylab (1973) and occupied since 1987 with the Salyut successor Mir. Uninterrupted human presence in orbital space through space stations has been sustained since the operational transition from the Mir to the International Space Station (ISS), with the latter's first occupation in 2000. There are currently two fully operational space stations – the ISS, occupied since Expedition 1 in October 2000, and China's Tiangong Space Station (TSS), occupied since June 2022 since the Shenzhou 14 mission. The highest number of people at the same time on one space station has been 13, first achieved with the eleven day docking to the ISS of the 127th Space Shuttle mission in 2009. The record for most people on all space stations at the same time has been 17, first reached on May 30, 2023, with 11 people on the ISS and 6 on the TSS. Space stations are often modular, featuring docking ports, through which they are built and maintained. Docking ports allow for the joining or movement of modules and the docking of other spacecraft for the exchange of people, supplies and tools. While space stations generally do not leave their orbit, they do feature thrusters for station keeping.
History
Early concepts The first mention of anything resembling a space station occurred in Edward Everett Hale's 1868 "The Brick Moon". 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.
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. 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. 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.
First advances and precursors
The first human flew to space and concluded the first orbit on April 12, 1961, with Vostok 1. Early space station designs were mainly paper concepts but work from 1959 to 1961 at Convair resulted in a full-scale mock-up Manned Astronomical Research Station to evaluate on the ground. The Apollo program had in its early planning instead of a lunar landing a crewed lunar orbital flight and an orbital laboratory station in orbit of Earth, at times called Project Olympus, as two different possible program goals, until the Kennedy administration sped ahead and made the Apollo program focus on what was originally planned to come after it, the lunar landing. The Project Olympus space station, or orbiting laboratory of the Apollo program, was proposed as an in-space unfolded structure with the Apollo command and service module docking. While never realized, the Apollo command and service module would perform docking maneuvers and eventually become a lunar orbiting module which was used for station-like purposes. But before that, the Gemini program paved the way and achieved the first space rendezvous (undocked) with Gemini 6 and Gemini 7 in 1965. Subsequently in 1966 Neil Armstrong performed on Gemini 8 the first ever space docking, while in 1967 Kosmos 186 and Kosmos 188 were the first spacecrafts that docked automatically.
In January 1969, Soyuz 4 and Soyuz 5 performed the first docked, but not internal, crew transfer, and in March, Apollo 9 performed the first ever internal transfer of astronauts between two docked spaceships.
Salyut, Almaz and Skylab
In 1971, the Soviet Union developed and launched the world's first space station, Salyut 1. 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 consumed, the station was abandoned. 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. 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. 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.
Mir
… excerpt ends here. Continue reading the full article.
