Soyuz 15 was a 1974 manned space flight which was to have been the second mission to the Soviet Union

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....

's Salyut 3

Salyut 3

Salyut 3 was a Soviet space station launched on June 25, 1974. It was the second Almaz military space station, and the first such station to be launched successfully. It was included in the Salyut program to disguise its true military nature...

 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...

 with presumably military objectives.

Launched 26 August 1974, the Soyuz

Soyuz spacecraft

Soyuz , Union) is a series of spacecraft initially designed for the Soviet space programme by the Korolyov Design Bureau in the 1960s, and still in service today...

 spacecraft arrived at the station, but cosmonauts Lev Dyomin

Lev Dyomin

Lev Stepanovich Dyomin was a Soviet cosmonaut who flew on the Soyuz 15 spaceflight in 1974. This spaceflight was intended to dock with the space station Salyut 3, but the docking failed....

 and Gennadi Sarafanov

Gennadi Sarafanov

Gennadi Vasiliyevich Sarafanov was a Soviet cosmonaut who flew on the Soyuz 15 spaceflight in 1974. This mission was intended to dock with the space station Salyut 3, but failed to do so after the docking system malfunctioned....

 were unable to dock because of a fault in the automated docking system. Without sufficient fuel for prolonged attempts at manual docking, the mission had to be abandoned. The crew landed 28 August. Analysis of the launch window

Launch window

Launch window is a term used in spaceflight to describe a time period in which a particular launch vehicle must be launched. If the rocket does not launch within the "window", it has to wait for the next window....

 was cited by observers for concluding a flight of 19 to 29 days had been planned.

It was later claimed by Soviet authorities that no docking had been intended and that the flight had been undertaken merely to develop techniques for maneuvering near the space station. They also said that a new automatic docking system was tested which would be used on future Progress transport craft.

Crew

Backup crew

Reserve crew

Mission parameters

• Mass: 6760 kg (14,903.2 lb)
• Perigee: 173 km (107.5 mi)
• Apogee: 236 km (146.6 mi)
• Inclination: 51.6°
• Period: 88.5 min