Soyuz 20 (russian: Союз 20, Union 20) was an unmanned spacecraft launched by the Soviet Union. It was a long-duration test of the

Soyuz spacecraft Soyuz () is a series of spacecraft which has been in service since the 1960s, having made more than 140 flights. It was designed for the Soviet space program by the Korolev Design Bureau (now Energia). The Soyuz succeeded the Voskhod spacecraf ...

that docked with the

Salyut 4 Salyut 4 (DOS 4) (russian: Салют-4; English translation: Salute 4) was a Salyut space station launched on December 26, 1974 into an orbit with an apogee of 355 km, a perigee of 343 km and an orbital inclination of 51.6 degrees. It ...

space station A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time, and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station i ...

. Soyuz 20 performed comprehensive checking of improved on-board systems of the spacecraft under various flight conditions. It also carried a biological payload. Living organisms were exposed to three months in space.

Mission parameters

*Mass: *Perigee: *Apogee: *Inclination: 51.6° *Period: 88.8 minutes

Return

It was recovered on 16 February 1976 at 02:24 UTC.

References

{{Orbital launches in 1975 Soyuz uncrewed test flights Spacecraft launched in 1975 Spacecraft which reentered in 1976 Spacecraft launched by Soyuz-U rockets