Soyuz 31 (Russian: Союз 31, Union 31) was a 1978 Soviet manned space flight to the Salyut 6 space station. It was the seventh mission to and sixth successful docking at the orbiting facility. The Soyuz 31 crew were the second to visit the long-duration Soyuz 29 resident crew. Soyuz 31 carried Valery Bykovsky and Sigmund Jähn, the first German cosmonaut, into space. They swapped Soyuz craft with the long-duration crew and returned to earth in Soyuz 29, the resident crew returned to earth in Soyuz 31.