History: ESA's first satellite, Cos-B, 1974

Cos-B, 1974: The Trigger Telescope for Cos-B's gamma-ray detector package being prepared for assembly at MBB, Germany, in February 1974. The cylinders are photomultiplier tubes. Cos-B was the first satellite from the newly formed European Space Agency. It was launched on 9 August 1975 and provided the first complete galactic survey in high-energy gamma-rays. Before this, the gamma-ray Universe had largely been invisible to astronomers. Designed for a 1-2 year lifetime, it operated successfully until April 1982. [74.02.031-007]