Mir (Russian: Мир; lit. Peace, World or Society) was a Soviet and later Russian space station, operational in low Earth orbit from 1986 to 2001. With a greater mass than that of any previous space station, Mir was the first of the third generation type of space station, constructed from 1986 to 1996 with a modular design, and was the largest artificial satellite orbiting the Earth until its deorbit on 21 March 2001, a record now surpassed by the International Space Station (ISS). Mir served as a microgravity research laboratory in which crews conducted experiments in biology, human biology, physics, astronomy, meteorology and spacecraft systems, with an aim to develop technologies required for the permanent occupation of space. The station was the first consistently inhabited long-term research station in space, and was operated by a series of long-duration crews. The Mir programme currently holds the record for the longest uninterrupted human presence in space, at 9 years and 257 days, and for the longest single human spaceflight, of Valeri Polyakov, at 437 days 18 hours. Mir was occupied for a total of twelve and a half years of its fifteen-year lifespan, having the capacity to support a resident crew of three and larger crews for short-term visits.
Following the success of the Salyut programme, Mir represented the next stage in the Soviet Union's space station programme. The first module of the station, known as the core module or base block, was launched in 1986, and was followed by six further modules, all being launched by Proton rockets (with the exception of the docking module). When complete, the station consisted of seven pressurised modules and several unpressurised components. Power was provided by several solar arrays mounted directly to the modules. The station was maintained at an orbit between 296 km (184 mi) and 421 km (262 mi) altitude and travelled at an average speed of 27,700 km/h (17,200 mph), completing 15.7 orbits per day.[6][7][8]
The station was originally launched as part of the Soviet Union's manned spaceflight programme's effort to maintain a long-term research outpost in space, and, following the collapse of the USSR, was operated by the new Russian Federal Space Agency (RKA). As a result, the vast majority of the station's crew were Soviet or Russian, however, through a number of international collaborations, including Intercosmos, Euromir and the Shuttle-Mir Program, the station was made accessible to astronauts from North America, several western European nations and Japan, as well as cosmonauts from various eastern nations. The cost of the station was estimated by Yuri Koptev in 2001 as $4.3 billion over the lifetime of the station, including its development, assembly and orbital operation, making Mir the eleventh most expensive object ever constructed.[12] The station was serviced by Soyuz spacecraft, Progress spacecraft and (during the Shuttle-Mir programme) US space shuttles.
