STS-55 (Space Transportation System 55), or D-2 was the 55th overall flight of the US Space Shuttle and the 14th flight of Shuttle Columbia. This flight was a multinational Spacelab flight involving 88 experiments from eleven different nations. The experiments ranged from biology sciences to simple earth observations.
Low Earth OrbitUS-PM (Upravlenniye Sputnik Passivny Modifikirovanny) (also reported as US-PU) was a solar powered improved EORSAT (Electronic Ocean Reconnaissance Satellite). It used an passive ELINT devices to track naval vessels from space by registering their electronic emmissions.
Low Earth Orbit