GEOS (NASA)
GEOS ( Geodetic Earth Orbiting Satellite ) was a series of three US geodetic research satellites of NASA .
The first two GEOS satellites (launched in 1965 and 1968) were developed under the Explorer program . They had a position stabilization by means of gravity gradients and an energy supply via solar cells . The GEOS satellites were the first missions in the National Geodetic Satellite Program .
The equipment consisted of a number of optical and radio systems (including a transponder each for the SECOR system) for exact path tracking as well as laser reflectors. As active satellites , they were a further development of the ANNA 1B probe and were able to emit short series of six to eight bright flashes of light . These were photographed synchronously against the star background by ground stations ( stellar triangulation ) in order to build up large-scale surveying networks through precise direction measurements.
The aim of the missions was to measure selected observation points with an accuracy of ten meters in a three-dimensional coordinate system with the center of mass of the earth as the center. Furthermore, the structure of the irregular earth's gravitational field and the position of the large gravitational anomalies were determined.
The GEOS-3 satellite (also Geodynamics Experimental Ocean Satellite due to the extended tasks ) was an extended version of the two previous satellites. This satellite was no longer part of the Explorer program. In addition to task the predecessor was by a radar - altimeter for precise measurement of ocean heights possible, allowing further refinement of the Earth's gravity model. In addition, an orbit tracking experiment was carried out with the experimental communication satellite ATS 6 . An improved version of the GEOS-3 satellite was launched by the US Navy under the name Geosat .
Satellites in the GEOS program
- GEOS 1 (Explorer 29) (before the start of GEOS A ) was launched from Cape Canaveral on November 6, 1965 with a Delta-E rocket.
- GEOS 2 (Explorer 36) (before launch, GEOS B ) followed on January 11, 1968 from Vandenberg (California) on a Delta E rocket.
- GEOS 3 (before the start of GEOS C ) was finally launched on April 9, 1975, also from Vandenberg on a Delta 1410 rocket.
Web links
- GEOS 1 in the NSSDCA Master Catalog (English)
- GEOS 2 in the NSSDCA Master Catalog (English)
- GEOS 3 in the NSSDCA Master Catalog (English)