Infobox Space mission
mission_name = Soyuz 29
sign = Photon
crew_members = 2
launch_pad = Gagarin's Start
launch = June 15, 1978 20:16:45 UTC
landing = September 3, 1978 11:40:34 UTC
46° N, 69° E
duration = 79d/15:23:49
apogee = 266 km
perigee = 197.8 km
period = 88.86 minutes
inclination = 51.65°
mass = 6800 kg
previous =
next = Soyuz 30

Crew

Number in parentheses indicates number of spaceflights by each individual prior to and including this mission.

Launched:
*Vladimir Kovalyonok (2) - Commander
*Aleksandr Ivanchenkov (1) - Flight Engineer

Landed:
*Valery Bykovsky (3) - Commander
*Sigmund Jähn (East Germany) (1) - Research Cosmonaut

Backup crew

*Vladimir Lyakhov - Commander
*Valeri Ryumin - Flight Engineer

Mission parameters

*Mass: 6800 kg
*Perigee: 197.8 km
*Apogee: 266 km
*Inclination: 51.65°
*Period: 88.86 minutes

served as their backup crew. They were the second long-duration crew of Salyut 6.

Upon arriving at Salyut 6, Kovalyonok and Ivanchenkov switched on the station’s air regenerators and thermal regulation system, and activated the water recycling system to reprocess water left aboard by the Tamyrs. De-mothballing Salyut 6 occurred simultaneously with the crew’s adaptation to weightlessness, and required about one week. On June 19 Salyut 6 was in a 368 km by 338 km orbit. Onboard temperature was 20 °C (68 °F), and air pressure was 750 mmHg (100 kPa). Soon after this, Kovalyonok and Ivanchenkov performed maintenance on the station’s airlock, installed equipment they brought with them in Soyuz 29’s orbital module, and tested the station’s Kaskad orientation system. The station operated in gravity-gradient stabilized mode June 24–June 26 to avoid attitude control system engine firings which could cause interference with a 3-day smelting experiment using the Splav-01 furnace. The previous crew installed the furnace in the intermediate compartment so it could operate in vacuum.

During their stay on board of Salyut 6 two visiting crews docked with the station. The second one exchanged the Soyuz spacecraft, allowing the crew to stay in space longer than the designated lifetime of the spacecraft. They landed with the Soyuz 31 spacecraft on November 2, 1978.

The Soyuz 29 spacecraft landed with the visiting crew which launched with Soyuz 31: Valery Bykovsky and Sigmund Jähn, the first German cosmonaut.

The capsule is on display in the "Deutsches Museum" in Munich, Germany, on loan from the "Militärhistorisches Museum" in Dresden, Germany.