March 15, 1978 
GEOS-3 
(Geodynamics Experimental Ocean Satellite) 
LAUNCH DATE: April 9, 1975 
ORBIT: Circular 
Altitude: 
Apogee: 848 km 
Perigee: 839 km 
Inclination: 114.9° 
Period: 101.7 minutes . 
SENSORS: 
Radar altimeter (accuracy of 1 meter over water) 
Coherent and noncoherent C-band transponders 
S-band instrumentation 
Laser retroreflectors 
(4 Doppler transmitters | : "e 
DESCRIPTION: Octahedron 132 cm wide topped by truncated pyramid 
16 solar cell panels 
Gravity-gradient stabilization scissors boom assembly with end 
mass of 45 kg extends to 6.5 m in orbit plane 
Height: 81 cm 
Weight: 340 kg 
PURPOSE: 
Measure geometry of oceans, topography of surface, currents, and 
circulation. 
Land and ice tracking. 
Fulfill oceanographic, geodetic, and radar calibration requirements. 
Used with ATS-6 in satellite-to-satellite tracking experiment. 
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