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| Mission type | Docking with Salyut 5 |
|---|---|
| Operator | Soviet space program |
| COSPAR ID | 1976-064A |
| SATCAT no. | 08934 |
| Mission duration | 49 days 6 hours 23 minutes 32 seconds ~60 days (planned) |
| Orbits completed | 790 |
| Spacecraft properties | |
| Spacecraft | Soyuz 7K-T No.9 |
| Spacecraft type | Soyuz 7K-T/A9 |
| Manufacturer | NPO Energia |
| Launch mass | 6750 kg [1] |
| Landing mass | 1200 kg |
| Crew | |
| Crew size | 2 |
| Members | Boris Volynov Vitaly Zholobov |
| Callsign | Байкал (Baikal - "Lake Baikal") |
| Start of mission | |
| Launch date | 6 July 1976, 12:08:45 UTC |
| Rocket | Soyuz |
| Launch site | Baikonur Site 1/5[2] |
| End of mission | |
| Landing date | 24 August 1976, 18:32:17 UTC |
| Landing site | 200 km at the southwest of Kokshetau, Kazakhstan |
| Orbital parameters | |
| Reference system | Geocentric orbit[3] |
| Regime | Low Earth orbit |
| Perigee altitude | 193.0 km |
| Apogee altitude | 253.0 km |
| Inclination | 51.6° |
| Period | 88.7 minutes |
| Docking with Salyut 5 | |
| Docking date | 7 July 1976 |
| Undocking date | 24 August 1976 |
| Time docked | 48 days |
 Vimpel Diamond patch | |
Soyuz 21 (Russian: Союз 21, Union 21) was a 1976 Soviet crewed mission to the Salyut 5 space station, the first of three flights to the station.[4] The mission's objectives were mainly military in scope, but included other scientific work. The mission ended abruptly with cosmonauts Boris Volynov and Vitaly Zholobov returning to Earth after 49 days in orbit. The precise reason for the early end of the mission was the subject of much speculation, but was reported to be an emergency evacuation after the Salyut atmosphere developed an acrid odor.
- ^ Cite error: The named reference
Displaywas invoked but never defined (see the help page). - ^ "Baikonur LC1". Encyclopedia Astronautica. Archived from the original on 15 April 2009. Retrieved 4 March 2009.
- ^ Cite error: The named reference
Trajectorywas invoked but never defined (see the help page). - ^ The mission report is available here: http://www.spacefacts.de/mission/english/soyuz-21.htm