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GEOS-2 satellite
GEOS-3
press photo taken of the GEOS-2 satellite in the final construction phase

GEOS

Geodetic and Earth Orbiting Satellite
State: Past

The Geodetic Earth Orbiting Satellite (GEOS) program developed three satellites for geodetic studies and for satellite-to-satellite tracking. 

  • GEOS 1 was launched on November 6, 1965, and was a gravity-gradient-stabilized, solar-cell powered spacecraft that carried electronic and geodetic instrumentation. Also known as Explorer 29.
  • GEOS 2 was launched on January 11, 1968, and was identical to the GEOS 1 satellite. Also known as Explorer 36.
  • GEOS 3 was launched on April 9, 1975, and was later renamed the Geodynamics Experimental Ocean Satellite. GEOS 3 was an octahedron spacecraft, topped by a truncated pyramid, with a parabolic reflector for a radar altimeter on the flat-bottom side.