User:Nancystodd/Raduga (satellite)

Raduga (Радуга, Rainbow), also known by its military name, Gran (Грань, Edge), GRAU index 11F638, is a series of Russian, previously Soviet, geosynchronous communications satellites launched between 1974 and 1999. The Raduga satellites were the first geosynchronous communications satellites in the Soviet Union. Deployed for both civilian and military purposes, they provided support to the Orbita ground TV network, and telephone and telegraph communications across the entire Eastern hemisphere except for polar regions.

The first satellite, designated as Kosmos 637/Raduga GVM, was launched on 26 March 1974. This satellite was not operational and was likely an engineering test of placement in geosynchronous orbit. The first functional Raduga satellite, Raduga 1, was launched on December 22, 1975 and was put in orbit at 85 degrees East. It was the first satellite in the Statsionar-1 network. The last satellite in the series, Raduga 34, was launched on 9 July 1999 but failed after a stage 2 explosion

The Raduga satellites utilized the KAUR-3 satellite bus, which provides three-axis stabilization using liquid propellant engines to within 0.25 degrees of the earth's center. The satellite constellation was replaced by the Raduga-1/Globus satellite constellation.