Mir (Russian: Мир, IPA: [ˈmʲir]; lit. 'peace' or 'world') was a space station operated in low Earth orbit from 1986 to 2001, first by the Soviet Union and later by the Russian Federation. Mir was the first modular space station and was assembled in orbit from 1986 to 1996. At the time it was the largest artificial satellite in orbit, only being succeeded by the International Space Station (ISS) after Mir's deorbiting in 2001. The station served as a microgravity research laboratory in which crews conducted experiments in biology, human biology, physics, astronomy, meteorology, and spacecraft systems with a goal of developing technologies required for permanent occupation of space. Mir was the first continuously inhabited long-term research station in orbit and previously held the record for the longest continuous human presence in space at 3,644 days, until it was surpassed by the ISS in 2010. It holds the record for the longest single human spaceflight, Valeri Polyakov, who spent 437 days on the station from 1994 until 1995. Mir's typical crew size was 3, though larger short-term crews made an appearance, peaking at ten during STS-71. Occupied for twelve and a half years out of its fifteen-year lifespan, 105 cosmonauts and astronauts from 12 different nations visited the station, and conducted 80 spacewalks. Mir was the next stage of the Soviet space programme's station development, following the success of six crewed single-module stations under the Salyut programme; its inaugural flight, Soyuz T-15, also conducted the only station-to-station trip, docking with Salyut 7 during its mission. Consisting of seven pressurised modules and several unpressurised components, its initial Core Module was launched in 1986. Proton rockets launched all components, except the Docking Module, which was installed by the Space Shuttle on STS-74. Power was provided by several photovoltaic arrays attached directly to the modules. The station was maintained at an orbit between 296 and 421 km (184 and 262 mi) altitude, completing 15.7 orbits per day at an inclination of 51.6°. Initially, the station was operated by NPO Energia with subcontracting to KB Salyut. Following the dissolution of the Soviet Union, Mir was operated by the Russian Federal Space Agency (RKA). Most of the station's occupants were Soviet/Russian; through international collaborations such as the Interkosmos, Euromir and Shuttle–Mir programmes, the station was made accessible to space travellers from several Asian, European and North American nations. Mir was deorbited in March 2001 after funding was cut off. The cost of the Mir programme was estimated by former RKA General Director Yuri Koptev in 2001 as $4.2 billion over its lifetime (including development, assembly and orbital operation). As of 2026, five of the ten longest human spaceflights ever were aboard Mir.
Origins Mir was authorised by a 17 February 1976 decree, to design an improved model of the Salyut space stations. Four Salyut space stations had been launched since 1971; three more were launched during Mir's development. It was planned that the station's core module (DOS-7 and the backup DOS-8) would have a total of four docking ports: one at each end of the station (as in the Salyut stations) and one on each side of a docking sphere at the front of the station to allow more modules to expand the station's capabilities. By August 1978, this had evolved to the final configuration: one aft port and five ports in a spherical compartment at the fore. It was originally planned that the ports would connect to 7.5-tonne (8.3-short-ton) modules derived from the Soyuz spacecraft. These modules would have used a Soyuz propulsion module, as used in Soyuz and Progress; and the descent and orbital modules would have been replaced with a long laboratory module. Following a February 1979 governmental resolution, the programme was consolidated with Vladimir Chelomei's crewed Almaz military space station programme. The docking ports were reinforced to accommodate 20-tonne (22-short-ton) space-station modules based on the TKS spacecraft. NPO Energia was responsible for the overall space station, with work subcontracted to KB Salyut, due to ongoing work on the Energia rocket, Salyut 7, Soyuz-T, and Progress spacecraft. KB Salyut began work in 1979, and drawings were released in 1982 and 1983. New systems incorporated into the station included gyrodyne flywheels (taken from Almaz), Kurs automatic rendezvous system, Luch satellite communications system, Elektron oxygen generators, and Vozdukh carbon dioxide scrubbers and the Salyut 5B digital flight control computer, although the Salyut 5B computer was not installed until the delivery of the Kvant-2 module. In early 1984, work on Mir had halted while all resources were being put into the Buran programme to prepare the Buran spacecraft for flight testing. Funding resumed in early 1984 when Valentin Glushko was ordered by the Central Committee's Secretary for Space and Defence to orbit Mir by early 1986, in time for the 27th Communist Party Congress. It was clear that the planned processing flow could not be followed and still meet the 1986 launch date. It was decided on Cosmonaut's Day (12 April) 1985 to ship the flight model of the base block to the Baikonur Cosmodrome and conduct the systems testing and integration there. The module arrived at the launch site on 6 May, with 1100 of 2500 cables requiring rework based on the results of tests to the ground test model at Khrunichev. In October, the base block was rolled outside its cleanroom to carry out communications tests. The first launch attempt on 16 February 1986 was scrubbed when the spacecraft communications failed, but the second launch attempt, on 19 February 1986 at 21:28:23 UTC, was successful, meeting the political deadline.
Station structure
Assembly
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