Gamma

Gamma was a Soviet gamma ray telescope. It was launched on 11 July 1990 into an orbit around Earth with a height of 375 km and an inclination of 51.6 degrees. It lasted for around 2 years. On board the mission were three telescopes, all of which could be pointed at the same source. The project was a joint Soviet-French project. The Gamma-1 telescope was the main telescope. It consisted of 2 scintillation counters and a gas Cerenkov counter. With an effective area of around 0.2 square metres (2.2 sq ft), it operated in the energy range of 50 MeV to 6 GeV. At 100 MeV it initially had an angular resolution of 1.5 degrees, with a field of view of 5 degrees and an energy resolution of 12%. A Telezvezda star tracker increased the pointing position accuracy of the Gamma-1 telescope to 2 arcminutes by tracking stars up to an apparent magnitude of 5 within its 6 by 6 degree field of view. However, due to the failure of power to a spark chamber, for most of the mission the resolution was around 10 degrees. The telescope was conceived in 1965, as part of the Soviet Cloud Space Station, which evolved into the Multi-module Orbital Complex (MOK). When work on Gamma finally began in 1972, it was intended to create a Gamma observatory, the first space station module for MOK, the first modular space station in the Salyut programme. For this, it was designed to add the scientific instruments of the observatory to a spacecraft derived from the Progress spacecraft – with the Progress in turn being a Soyuz spacecraft derivate – and that this spacecraft would dock to a MOK space station. However, in 1974, at the time it became a joint venture with France, the MOK space station project was canceled, and in February 1976, the Soviet space program was reconfigured.