Soyuz 34

Soyuz 34 (Russian: Союз 34, Union 34) was a 1979 Soviet unmanned space flight to the Salyut 6 space station. It was sent to supply the resident crew a reliable return vehicle after the previous flight, Soyuz 33, suffered an engine failure.

Mission control decided to re-design the engine used on Soyuz craft as a result of the Soyuz 33 failure, and to return the Soyuz 32 craft which transported Vladimir Lyakhov and Valery Ryumin to the space station to earth unmanned as it had the same suspect engine as Soyuz 33. Soyuz 34 successfully returned the crew to earth 73 days after launching.