Model of ESA's Exosat X-ray satellite with the Whirlpool Galaxy as a backdrop. On the front, from left to right, are two startrackers, the two low-energy imaging telescopes and the four quadrants of the medium-energy instrument. The gas scintillation proportional counter is visible to the right of the medium energy instrument. [Image Date: 01-03-81] [81.03.055-010]