Prognoz (satellite)

Prognoz, also known as SO (Solar Object, first three satellites), SO-M (SO-modified, next seven satellites), and SO-M2 (last two satellites, also known as Interball), was a Soviet scientific research satellite programme. Twelve Prognoz satellites were launched between 14 April 1972, and 29 August 1996, by Molniya-M carrier rockets. The satellites were placed in high Earth orbits. The first ten Prognoz satellites were launched from Site 31/6 at the Baikonur Cosmodrome, and the last two from Site 43/3 at the Plesetsk Cosmodrome.

The satellites were primarily used for Solar research; however, the later satellites were used for other kinds of research, including research into the Big Bang theory, and Earth's magnetosphere. The tenth satellite was used as part of the Interkosmos programme.