Learn about MIR space station

Soviet space station complex, the core module of which was launched in 1986. In subsequent years additional modules were lofted into space by separate rockets and attached to the docking ports of the core Mir unit, allowing the assembly of a permanently manned orbiting facility that could function as a large, flexible laboratory in space. Mir is the Russian word for "peace."

Mir was the third generation of Soviet space stations. The satellites of the first generation, Salyuts 1 through 5 (launched 1971-76), had only one docking port, while those of the second generation, Salyuts 6 and 7 (1977, 1982), had two docking ports. Mir's core module resembles that of Salyut 7 but has six docking ports, thus enabling a more complex station to be constructed in space. The docking ports can accommodate cargo ferries, visiting manned spacecraft, or expansion modules equipped as specialized research facilities.

Besides its six docking ports, Mir features expanded living quarters, greater available power, and modernized research equipment. The core module has a mass of 21 metric tons (23 tons), a length of 13.13 m (43 feet), and a width of 4.2 m (13.8 feet) at its maximum diameter. The core module is essentially a long cylinder, with a docking port at each end and four ports sited radially around a docking fixture at the forward end of the craft. The living area consists of two rooms end-to-end that are used for controlling the spacecraft, conducting research, dining, and recreation. There are also a bathroom and two small individual cabins. The station's electrical power is generated by two arrays of solar cell panels. The tail section of the core module has two large rocket engines that can make adjustments to the craft's orbit and 32 small thrusters that are used to control its attitude.

The core module of Mir was launched on Feb. 20, 1986, and on March 13, 1986, cosmonauts Leonid Kizim and Vladimir Solovyev were sent aloft aboard a Soyuz spacecraft to rendezvous with Mir and become its first occupants; they spent 53 days adjusting equipment and bringing the complex into workable order. On May 6 the two cosmonauts left Mir in the Soyuz craft and transferred to the still-orbiting Salyut 7 station, thus completing the first human transfer from one space station to another. Other cosmonauts soon visited the Mir station, which was kept supplied by periodic visits of unmanned Progress cargo ferries. Some cosmonauts stayed on the Mir for missons lasting six months or even a year. A record set by a Mir crew member in 1987 for the longest time (326 days) spent in space was broken (366 days) by two other Mir cosmonauts in December 1988, but these feats were far surpassed by Mir crewman Valery Polyakov, who returned to Earth on March 22, 1995, after having spent 438 days in space.

In March 1987 the Soviets launched the first large specialized module to the Mir complex. Known as Kvant ("Quantum") 1, this first module was basically an astrophysics observatory. It weighed more than 20 metric tons, almost as large as the basic Mir, and in itself almost doubled the habitable volume of the space station. The service module Kvant 2 (launched November 1989) contained equipment for producing oxygen and recycling the station's water supplies, as well as a shower, a sink, and an airlock for spacewalks so that cosmonauts could perform outside maintenance work. The technology module Kristall ( "Crystal"; May 1990) contained furnaces and other equipment for processing materials in space. This module was also fitted with a docking port for linkups with the Soviets' Buran space shuttle, which was later abandoned. The Spektr ("Spectrum") science module (May 1995) contained remote-sensing instruments to study the gases of the Earth's atmosphere. Mir's assembly was completed when Priroda ("Nature"), a science module containing remote-sensing instruments with which to study the Earth's environmental health and ecology, was docked to the station in April 1996. The aging Mir station suffered a series of equipment failures and accidents in 1996-97 but remained in service.