The International Ultraviolet Explorer

IUE was launched into geosynchronous (but not geostationary) orbit in 1978 (so this picture is of its engineering backup hanging in the National Air and Space Museum). The nominal mission was for 3 years, as of late 1994 it's still going, having obtained an archive of over 100,000 ultraviolet spectra of every kind of astronomical object. Observations with IUE have led to fundamental advances in stellar winds, galaxies, quasars, planetary aurorae... The satellite carries a 45-cm telescope and is powered by the twin fixed solar arrays seen here.

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