The exosat mission

Exosat, the European X-ray Observatory, was placed in orbit on 26 May 1983. The spacecraft, stabilized axes in three to a few arc second, carries four instruments, two one-metre focal length imaging telescopes, a large area proportional counter array and a gas scintillation proportional counter spectrometer. The salient features of the instrumentation, the sensitivities achieved in orbit and the status after the first year of orbital operation are described. Three specific observations, VO332+53, SCO X–1 and M.83 are discussed to demonstrate the power of the EXOSAT instrumentation and the operational flexibility of the spacecraft and ground system.