[4] The cosmonauts Viktor Gorbatko and Yuri Glazkov re-activated the station after toxic fumes had apparently terminated the mission of Soyuz 21, the previous crew.

Other presumed activities included photographic reconnaissance, and finishing tasks the previous crew was forced to abandon when their mission abruptly ended.

The cosmonauts Gorbatko and Glazkov were the back-up crew for Soyuz 23, which failed to dock with Salyut 5 several months earlier.

This was a test of the future air replenishment techniques to be carried out with Progress transports in subsequent space stations.

As it turned out, the search and rescue beacon was unable to deploy due to being jammed shut from snow, so Gorbatko had to free it by hand.