United States Navy satellite designed to measure sea surface heights to within 5 cm. After a year-and-a-half-long classified mission, Geosat`s scientific Exact Repeat Mission (ERM) began on Nov. 8, 1986. When the ERM ended in Jan. 1990 (due to failures of both onboard tape recorders), more than thre... Found on http://www.daviddarling.info/encyclopedia/G/Geosat.html