Development of a new kind of Soviet space station module, designated 37K, was authorised on 17 September 1979. The basic 37K design consisted of a 4.2 m diameter pressurised cylinder. The 37KB modules, similar to the Kvant module of the Mir space station, were to be standard on the early Buran flights. A later version of the design for military experiments, the NPG Retained Payload, would be mounted in the payload bay of Buran and connected to the orbiter's cockpit area by an access tunnel. Work on the 37KB modules was finally stopped completely when further Buran funding was ended in 1993.
Total Length: 5.1 m. Maximum Diameter: 4.2 m. Total Habitable Volume: 37.00 m3. Total Mass: 7,150 kg.
The basic 37K design consisted of a 4.2 m diameter pressurised cylinder with a docking port at the forward end. It was not equipped with its own propulsion system. The original authorisation was for a total of eight 37K's of various configurations. Of these, only the 37K-E (Kvant module of Mir) and the 37KS (instrumentation module in Buran) would fly.