was a Soviet
space mission, launched in 1978
. It carried two cosmonaut
s (Vladimir Kovalyonok
and Aleksandr Ivanchenkev
) from Launch Complex 1 at the Baikonur cosmodrome
to the Salyut 6
space station, launching on June 15, 1978
and docking at the forward docking port of Salyut 6
the next day. It did not return with the same crew, however; the Soyuz 31
was launched on August 26th, 1978
and docked a day later. It carried Valeri Bykovsky
and Sigmund Jähn
, the latter of the German Democratic Republic
. They returned a week later, undocking on September 3 in Soyuz 29
and landing that same day safely. This ends the official Soyuz 29
mission, spanning some two and half months and two different crews.
The reason for the capsule swap is that the original crew was scheduled to stay on board the station until November of that year. However, that mission duration exceeded the 'usable lifespan' of the Soyuz spacecraft; as a result, new capsules had to be ferried up to the station by additional crews. The Soviet Union used this as an opportunity to staff the station up to four cosmonauts for short periods of time (typically a week) and to offer some of these 'extra seats' to Eastern Bloc states for diplomatic and publicity purposes.
During their stay, Kovalyonok and Ivanchenkev performed a two-hour spacewalk to retrieve samples stored on the outside of the station. In addition, they performed a week-long de-mothballing procedure on arrival (the station had been powered down since earlier that year), installed equipment brought with them, and undertook numerous scientific and engineering experiments. Kovalyonok and Ivanchenkev returned to Earth on November 3, 1978 in the Soyuz 31 capsule, landing southeast of Dzhezkazgan in Kazakhstan. The Soyuz 29 capsule ended up on display in Germany due to its carrying the (first) GDR cosmonaut home. It can be seen today in the Deutsches Museum in Munich.
Mission Call Sign: Photon
Total Duration: 79 days, 15 hours, 23 minutes