Gamma was an orbiting Soviet gamma-ray and X-ray telescope derived from Soyuz manned spacecraft hardware. It was originally conceived in 1965 as part of a "Cloud Space Station"– a primary space station from which a number of man-tended, free-flying spacecraft would operate. This had evolved by the early 1970s into the MKBS/MOK space station complex. Various spacecraft with specialized laboratories or instrument sets, including Gamma, would fly autonomously away from the N-1-launched main station. The Soyuz propulsion system would be used, but the descent and orbital modules were replaced by a large pressurized cylinder containing the scientific instruments.

 

Work on the instrument payload for Gamma began in 1972, and French participation began in 1974. However that same year the N-1 launch vehicle and the MKBS space station were cancelled. The Soviet space program was completely reformulated and authorization given to develop the free flyer in conjunction with the DOS-7/DOS-8 space station, which would eventually evolve into Mir. The draft project for Gamma was completed in 1978, and production was authorized together with Mir in February 1979. At this point Gamma included a passive docking port so that the spacecraft could be serviced by Soyuz manned spacecraft. It was planned that at 6–12 months into its one-year mission Gamma would be visited by a two-crew Soyuz, who would replace film cassettes and repair or replace instruments. This approach was dropped in 1982 when it became clear that the spacecraft was overweight and that all planned Soyuz would be needed to support Mir itself. All film systems were removed and replaced with purely electronic data return methods. By that time Gamma was scheduled originally for launch in 1984, but further technical delays resulted in a 1990 launch, 25 years after it was first conceived. In the end the satellite's research in the field of high-energy astrophysics, conducted jointly with France and Poland, did not produce many noteworthy results.

 

launch date	Jul 11, 1990
vehicle	Soyuz
site	Baikonur
orbit	382 × 387 km × 51.6°
size	7.7 × 2.7 m
mass	7,350 kg