User:WDGraham/DOS (spacecraft)

DOS (ДОС, Длительной Орбитальный Станция meaning Long-duration Orbital Station), also known as Salyut (Салю́т meaning Salute) and originally Zarya (Заря́ meaning Dawn) is a Russian, previously Soviet spacecraft. It has the GRAU index 11F715. Six were launched as part of the Salyut programme, with two later being used as components of Mir and the International Space Station. All eight launches used Proton-K rockets, flying from the Baikonur Cosmodrome in Kazakhstan.

DOS spacecraft were originally designed for use as monolithic space stations for the Salyut programme. The first six spacecraft used this configuration. The seventh and eighth spacecraft were later modified for use in modular space stations, and were used as the core module of Mir, and the service module of the ISS. Four of the six inhabited Salyut stations were DOS spacecraft, including Salyut 1, the world's first space station.

DOS-1 (Salyut 1)


Salyut 1, the first DOS spacecraft, was the first space station to be launched. It was launched on 19 April 1971, and its first crew was launched aboard Soyuz 10 on 22 April, however their spacecraft was unable to dock. Soyuz 11 was launched on 6 June, and was able to dock successfully.

Following undocking, Soyuz 11 performed its deorbit burn, and jettisoned its instrumentation and propulsion module. Following separation, the descent module depressurised, killing the three cosmonauts aboard it.

DOS-2
DOS-2 was launched on 29 July 1972, but failed to reach orbit due to a malfunction of its Proton-K carrier rocket.

DOS-3 (Kosmos 557)
DOS-3 was launched on 11 May 1973, but failed immediately after reaching orbit. It was given the cover designation Kosmos 557, and decayed naturally from orbit on 22 May.

DOS-5 (Salyut 6)


DOS-5 was launched on 29 September 1977 as Salyut 6. It was the first DOS spacecraft to feature multiple docking ports, with one aft mounted port and one forward mounted port. This enabled multiple Soyuz spacecraft to dock at the same time; allowing cosmonauts to visit the station whilst a long-duration crew was aboard. It also enabled unmanned missions to resupply and refuel the station, with the Progress spacecraft being developed for this purpose.

DOS-6 (Salyut 7)
DOS-6 was launched on 19 April 1982, and was designated Salyut 7 upon reaching orbit. The final space station of the Salyut programme, it was intended to conduct research into long duration and modular space stations, ahead of the planned Mir programme.

DOS-7 (Mir Core)


DOS-7 was launched on 19 February 1986 as the core module of the Mir space station. Unlike previous DOS spacecraft, it featured six docking ports to support multiple additional modules.

Mir remained in orbit until March 2001, when it was deorbited by the Progress M1-5 spacecraft.

DOS-8 (Zvezda)
DOS-8 was originally built as the core module for Mir-2. After this was cancelled, it was placed into storage, and later modified for use as the service module of the International Space Station.