Launch from Baikonur; landing 56 km east of Arkalyk.

Crew was originally backup crew for originally Soyuz 18A crew, but that launch failed. 2. crew of spacestation Salyut 4; 62 days staying time. For that reason the focus of the mission research into long-term stays in space, with the crew performing various biomedical experiments (includig intensive physically exercise) and growing plants in orbit. They also made solar observations and took photos of the Earths surface.

The crew remained aloft aboard the station during the ASTP joint flight.