GEOS-2, also known as GEOS-B and Explorer 36, was a NASA geodetic Earth-orbiting satellite launched on January 11, 1968. Optical beacons, C-band radar transponders, SECOR and range-rate systems, Doppler beacons, and laser retroreflectors supported precise tracking, gravity-field determination, geodetic datum improvement, and calibration of international tracking networks.
Alerts for directly linked future launches and major activity.