Soyuz 21
Encyclopedia
Soyuz 21 was a 1976 Soviet
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 manned mission to the Salyut 5
Salyut 5
Salyut 5 , also known as OPS-3, was a Soviet space station. Launched in 1976 as part of the Salyut programme, it was the third and last Almaz space station to be launched for the Soviet military. Two Soyuz missions visited the station, each manned by two cosmonauts...

 space station
Space station
A space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...

, 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
Boris Volynov
Boris Valentinovich Volynov is a Soviet cosmonaut who flew two space missions of the Soyuz programme: Soyuz 5, and Soyuz 21. He was the first Jewish cosmonaut.-Biography:...

 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

  • Mass: 6800 kg (14,991.4 lb)
  • Perigee: 246 km (152.9 mi)
  • Apogee: 274 km (170.3 mi)
  • Inclination: 51.6°
  • Period: 89.7 min

Mission highlights

Salyut 5
Salyut 5
Salyut 5 , also known as OPS-3, was a Soviet space station. Launched in 1976 as part of the Salyut programme, it was the third and last Almaz space station to be launched for the Soviet military. Two Soyuz missions visited the station, each manned by two cosmonauts...

, the last dedicated military space station
Space station
A space station is a spacecraft capable of supporting a crew which is designed to remain in space for an extended period of time, and to which other spacecraft can dock. A space station is distinguished from other spacecraft used for human spaceflight by its lack of major propulsion or landing...

 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.

Their stay coincided with the start of the Siber military exercise in Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

, which they observed as part of an assessment of the station’s military surveillance capabilities. They conducted only a few scientific experiments, including the first use of the Kristall furnace for crystal
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

 growth. Engineering experiments included propellant transfer system tests with implications for future operation of the freight-carrying Progress spacecraft
Progress spacecraft
The Progress is a Russian expendable freighter spacecraft. The spacecraft is an unmanned resupply spacecraft during its flight but upon docking with a space station, it allows astronauts inside, hence it is classified manned by the manufacturer. It was derived from the Soyuz spacecraft, and is...

.

Experiments conducted during the mission were mainly of a military nature as part of the Almaz
Almaz
The Almaz program was a series of military space stations launched by the Soviet Union under cover of the civilian Salyut DOS-17K program after 1971....

 program. Various purely scientific tasks were also carried out, including solar observations and biological observations of an aquarium of fish carried into orbit. A TV link-up with school children on 17 August was also undertaken.

On 24 August, it was announced the mission was to end in only 10 hours, a development which caught even the reporters of Radio Moscow by surprise. The reason for the sudden termination of the mission was reported at the time to have been an acrid odor that developed in the environmental control system. The problem was said to have begun as early as 17 August. The Soviets made no comments at the time, but the next crew to board the station wore breathing masks. Later reports indicate that the mission may have ended owing to a deterioration in the health of Zholobov.

The cosmonauts boarded Soyuz 21 but as Volynov tried to undock from the station, the docking latches failed to release properly. As he fired the jets to move the spacecraft away, the docking mechanism jammed, resulting in the Soyuz being undocked but still linked to Salyut. As the two spacecraft moved out of range of ground communications, the cosmonauts received only the first set of emergency procedures. Volynov tried a second time to undock but only managed slightly to loosen the latches. The situation persisted for an entire orbit, 90 minutes, when the final set of emergency procedures were received and the crew finally disengaged the latches.

Because Soyuz 21 was returning early, it was outside the normal recovery window. It then encountered strong winds as it descended, which caused uneven firing of the retrorockets. It made a hard landing around midnight 200 km (124.3 mi) southwest of Kokchetav, Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...

.

Zholobov's illness was apparently caused by nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...

 fumes leaking from the Salyut's propellant tanks; other reports, however, indicate that the crew failed to follow their physical exercise program and suffered from lack of sleep. Sources at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 have reported that psychologists with the Russian Aviation and Space Agency cited Soyuz 21 as ending prematurely due to unspecified "interpersonal issues" with the crew. The next mission to successfully dock with the station, Soyuz 24
Soyuz 24
Soyuz 24 was a 1977 Soviet mission to the Salyut 5 space station, the third and final mission to the station, the last purely military crew for the Soviets and the final mission to a military Salyut...

, would vent Salyut 5's air to space and replace it due to concerns the air had become toxic.
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