Soyuz 15 (russian: Союз 15, ''Union 15'') was an August, 1974, crewed space flight which was to have been the second mission to the Soviet Union's Salyut 3

space station A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time, and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station i ...

with presumably military objectives. Launched 26 August 1974, the

Soyuz spacecraft Soyuz () is a series of spacecraft which has been in service since the 1960s, having made more than 140 flights. It was designed for the Soviet space program by the Korolev Design Bureau (now Energia). The Soyuz succeeded the Voskhod spacecraf ...

arrived at the station, but cosmonauts

Gennady Sarafanov Gennady Vasiliyevich Sarafanov (; 1 January 1942 – 29 September 2005) 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 dockin ...

, and Lev Dyomin were unable to dock because the electronics in the

Igla docking system The Igla (russian: Игла, "Needle") docking system was a Soviet radio telemetry system for automated docking of Soyuz spacecraft. The first prototypes were made in late 1965. On 30 October 1967, the first automated docking of Soyuz unmanned spac ...

malfunctioned. Without sufficient fuel for prolonged attempts at manual docking, the mission had to be abandoned. The cosmonauts powered down all nonessential systems in the Soyuz and waited until the next day for reentry. The crew landed 28 August 1974. Analysis of the

launch window In the context of spaceflight, launch period is the collection of days and launch window is the time period on a given day during which a particular rocket must be launched in order to reach its intended target. If the rocket is not launched wit ...

was cited by observers for concluding a flight of 19 to 29 days had been planned. In the event of the failure, official TASS statements merely claimed that the mission was intended to practice docking maneuvers with the Salyut 3 station. They also said that a new automatic docking system was tested which would be used on future Progress transport craft. The failed mission exposed a number of serious design flaws in the Soyuz 7K-T spacecraft, namely its lack of reserve propellant and electrical power for repeated docking attempts. In addition, the Igla docking system was found to be in major need of improvement. Since it was impossible to carry out these changes before Salyut 3 finished its operating lifespan, they had to wait for future space stations. The backup spacecraft for the Soyuz 15 mission was placed in storage and later flown as

Soyuz 20 Soyuz 20 (russian: Союз 20, Union 20) was an unmanned spacecraft launched by the Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 170 ...

despite being past its intended shelf life.

Crew

Backup crew

Reserve crew

Mission parameters

*Mass: *Perigee: *Apogee: *Inclination: 51.60° *Period: 89.60 minutes

References

{{Orbital launches in 1974 Crewed Soyuz missions 1974 in spaceflight 1974 in the Soviet Union Spacecraft launched in 1974