Crew

• Boris Volynov (2)
• Vitali Zholobov (1)

(1) number of spaceflights each crew member has completed, including this mission.

Mission Parameters

• Mass: 6800 kg
• Perigee: 246 km
• Apogee: 274 km
• Inclination: 51.6°
• Period: 89.7 min

Mission highlights

Soyuz 21 carried cosmonauts Boris Volynov and Vitali Zholobov to the Salyut 5 space station.

The Salyut 5 crew’s stay coincided with the start of the Siber military exercise in Siberia. The cosmonauts observed the exercise as part of an assessment of the station’s military surveillance capabilities. They conducted only a few scientific experiments–these included first use of the Kristall furnace for crystal growth. Engineering experiments included propellant transfer system tests with implications for future Progress freighter operations.

Experiments conducted during the mission were mainly of a military nature as part of the Almaz programme. However, various purely scientific tasks were also carried out, including solar observations and biological observations (an aquarium of fish was carried into orbit). A TV link-up with school children was also undertaken.

The Soyuz 21 crew seems to have left the station suddenly, ahead of their scheduled departure date. This has been attributed to a fire, an environmental control system failure, and to health problems caused by fumes from chemicals used to develop film from the station’s surveillance cameras. Mention has been made of poisonous vapours present on the station, but the crew also seemed to be suffering psychologically and physically for other reasons. Zholobov in particular experienced terrible space-sickness and homesickness.