Soyuz T-3
The 13th expedition to Salyut 6 tested the three seat version of Soyuz T. First Soyuz since 1971 to carry three cosmonauts. It constituted a Salyut 6 refurbishment mission. The Mayaks were the first three-person space station crew since Soyuz 11 in 1971. Part of their mission was to further test the Soyuz-T. During their brief stay on Salyut 6, they performed the usual experiments using the Splav and Kristall units, and studied “biological objects” they brought with them in Soyuz-T 3. They used the Svetoblok and Oazis units. Much of their time, however, was devoted to space station maintenance.
On December 2 they commenced conducting the Mikroklimat experiment to assess the station’s living conditions, and began work on the thermal control system. They installed a new hydraulic unit with four pumps. On December 4 they replaced electronics in the Salyut 6 telemetry system. December 5 saw them repairing electrical system faults. Other repairs included replacement of a program and timing device in the onboard control system and replacement of a power supply unit for the compressor in the refueling system. The Salyut 6 Principal Expedition 4 crew in the TsUP provided the crew with advice as they made their repairs. On December 8 Progress 11 carried out an orbit correction for the complex.
Read more about Soyuz T-3: Crew