On July 6, 1976

 By Astrophilatelie Martin

On July 6, 1976, the Soyouz 21 spacecraft was launched from Baikonour with the cosmonauts Boris Volynov and Vitali Zholobov on board. Mooring at Saliout 5 orbital station on July 7. The experiments conducted during the mission were mainly military-oriented as part of the Almaz program. Various purely scientific tasks were also carried out, including solar observations and biological observations of an aquarium placed in orbit. Using the Kristall furnace for growing crystals. A liaison with school children on August 17 was also undertaken.

Throwback to August 24, 1976 after a flight of 49 days 6 hours 23 minutes and 791 Earth orbits. The mission ended abruptly with the cosmonauts returning to Earth after just over 49 days in orbit. The exact reason for the mission's premature end has been the subject of much speculation, but it was reported that it was an emergency evacuation after the atmosphere in Saliut developed a sour odor. Subsequent reports indicate the mission could have ended due to deteriorating health for Zholobov.