|Begin:||August 9, 1975, 01:48 UTC|
|Starting place:||Vandenberg AFB , SLC-2W|
|Status:||in orbit, out of order|
|Rotation time :||37 h|
|Orbit inclination :||90.13 °|
|Apogee height :||99876 km|
|Perigee height :||340 km|
COS-B was on August 9, 1975 a Delta rocket of NASA from the launch site Vandenberg placed in a highly eccentric orbit with 37 hours turnaround time, and had until April 25, 1982 in operation. The main instrument was a large, direction-resolving detector ( spark chamber ) for gamma radiation between about 30 MeV and 5 GeV energy, and there was also a detector for X-rays. COS-B was an ESA project with contributions from European research institutes on instrumentation.
The first map of the gamma radiation of our Milky Way , the 2CG catalog of 25 cosmic gamma sources, and investigations of individual objects such as pulsars and the first extragalactic gamma source 3C 273 emerged from the observations of COS-B .