Gravity Probe A

Gravity Probe A was a NASA geodetic satellite designed to test the general theory of relativity. Gravity Probe A carried a space-qualified hydrogen maser clock to an altitude of 10,000 kilometers on a two-hour suborbital flight and verified the gravitational red shift predicted by Einstein's theory to a precision of 70 parts per million. See also Gravity Probe B.


launch date Jun 18, 1976
launch vehicle Scout D
launch site Wallops Island