Tags: Artificialsatellite, Satellite.
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.