Cos-B

Cos-B, short for Celestial Observation Satellite B, was the first mission by the European Space Research Organisation to study cosmic gamma ray sources. It was suggested by European scientists in the mid-1960s and officially approved in 1969. The satellite carried special tools to detect gamma rays and was launched by NASA for the ESRO on August 9, 1975.

The mission lasted until April 25, 1982, more than six and a half years, which was four years longer than expected. During its time, Cos-B gathered a lot of important information about gamma rays, increasing what we knew by 25 times. Scientists made a list called the 2CG Catalogue with about 25 gamma ray sources and created a map of our Milky Way galaxy. The satellite also looked at a special system of stars known as the X-ray binary Cygnus X-3.

Launch

COS-B was sent into space from Vandenberg Air Force Base on August 9, 1975, using a Delta 2913 rocket.