GEOS3STST is the satellite-to-satellite tracking data product which contains observations, obtained from the S-band transponders on GEOS-3 relayed by the ATS-6 spacecraft to various ground stations, used for geodetic studies. GEOS-3, or the Geodynamics Experimental Ocean Satellite 3, was the third and final satellite as part of NASA's Geodetic Earth Orbiting Satellite/Geodynamics Experimental Ocean Satellite program. The Data are available for the time period from 1975-04-13 to 1976-04-28 in sixteen files, written in ASCII text, where each measurement is recorded as two lines of text.\n\nThe principal investigator for the Satellite-to-Satellite Tracking experiment was Indalecio Y. Galicinao from NASA/GSFC.