Molniya-1S

Molniya-1S was the first operating geostationary communications satellite of the Soviet Union. After the Kosmos 637 dummy satellite was put into geostationary orbit, the Soviet Union launched a modified Molniya-1 satellite into GEO. This experimental satellite was built by NPO Prikladnoi Mekhaniki and was based on the operational Molniya-1 series. This satellite was the only Molniya satellite to be put into geostationary orbit.