Soyuz 21

Soyuz 21 (Russian: Союз 21, Union 21) was a 1976 Soviet manned mission to the Salyut 5 space station, the first of three flights to the station. 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.

Crew

Backup crew

Reserve crew

Mission parameters

Mission highlights

Salyut 5, the last dedicated military space station in the Soviet space program, was launched 22 June 1976. Its first crew was launched 14 days later on 6 July, with Commander Volynov and Flight Engineer Zholobov aboard Soyuz 21. Based on landing opportunities, observers estimated the mission was intended to last 54 to 66 days. They docked with the station the next day, and gave a televised tour 8 July.