GEOS-3

Mission Specfication:

The Geodetic and Earth Ocean Satellite 3 (GEOS-3) was part of a geodetic mission series lead by NASA.  It launched April 9, 1975 and continued operating until July 1979.  GEOS-3 mission was to measure the gravitational field around the Earth, specifically to identify the irregularities and anomalies.  Gravitational anomalies over the ocean also can be used to measure large mesoscale circulation.
 
 
Instruments:
 
Two C-band antenna – Used to experiment what the accuracies would be for gravimetric and geometric measurements.
 
S-band tracking system – It consisted of an ATS and Earth viewing antennae, diplexer and transponder.  The transponder operated in three modes: satellite to satellite tracking, direct unified S-band and Goddard Range and Range Rate ground-station tracking.
 
Radar altimeter – Ku band altimeter, it was the first altimeter to measure sea surface height
 
Doppler beacon – Dual frequency, 162 and 324 MHz, Doppler used to measure ionosphere.
 
Retroreflector array – Used to calculate the orbit by using ground laser ranging.
 
 
Orbit:
 
Orbit:                        Non-sun synchronous
Launch Date:             9 April 1975
Inclination:             115 degrees
Perigee:             824 km
Apogee:            856 km
Period:             102 minutes
Weight:             346  kg
Eccentricity:             0.00115
Period:            101.82 minutes

Links:

• http://ilrs.gsfc.nasa.gov/satellite_missions/list_of_satellites/geos_general.html
• http://cddis.nasa.gov/926/egm96/geos3.html
• https://directory.eoportal.org/get_announce.php?an_id=9763

Publications:
 
Chapman, M.E. and Talwani, M., "Comparison of Gravimetric Geoids with GEOS-3 Altimetric Geoid", J. Geophys. Res., Vol. 84, pp. 3803-3816, 1979.
 
Eren, K., "Spectral Analysis of GEOS-3 Altimeter Data and Frequency Domain Collocation", OSU-Rpt. 297, 151pp, 1980.
 
Kahn, W. D., S. M. Klosko, and W. T. Wells, "Mean gravity anomalies from a combination of Apollo/ATS 6 and GEOS-3/ATS 6 SST tracking campaigns," J. Geophys. Res., 87, 2904-2918, 1982.
 
Klosko, S.M., Lerch, F.J., Belott R.P., and Litkowski, E.M., "Laser Reference Orbits and Altimeter Validation for GEOS-3", Marine Geodesy Symposium, RSMAS, U. Miami, 1978.
 
Lemoine, F.G., "The 1998 to 1999 GEOS-3 Tracking Campaign: Analysis and Results", NASA Tech. Rept., NASA Goddard Space Flight, Jan 01, 1999.
 
Lerch, F.J., Klosko, S.M., Laubscher, R.E., and Wagner, C.A., "Gravity Model Improvement Using GEOS-3 (GEM 9 and 10)", NASA Doc. No. X-921-77-246, 121pp, 1977.
 
Lerch, F.J., Klosko, S.M., Laubscher, R.E., and Wagner, C.A., "Gravity Model Improvement Using GEOS-3 (GEM-9 and 10)", NASA X-921-77-246, September, 1977.
 
Lerch, F. J., Klosko, S. M., Laubscher, R. E., Wagner, C. A., "Gravity Model Improvement Using GEOS-3 (GEM-9 and 10)", J. Geophys. Res., 84(138), 3897-3915, 1979.
 
Marsh, J.G., Marsh, B., Conrad, T., Wells, W., and Williamson, R., "Gravity Anomalies Near the East Pacific Rise with Wavelengths Shorter than 3300 km Recovered from GEOS-3, ATS-6, Satellite-to-Satellite Doppler Tracking Data", The Use of Artificial Satellites for Geodesy and Geodynamics, pp. 296-342, 1979.
 
Marsh, J.G., Martin, T., McCarthy, J.J., and Chovitz, P., "Estimation of Mean Sea Surfaces in the North Atlantic, the Pacific, and the Indian Ocean Using GEOS-3 Altimetry Data", The Use of Artificial Satellites for Geodesy and Geodynamics, pp. 414-447, 1979.
 
Marsh, J.G., Koblinsky, C.J., Zwally, H.J., Brenner, A.C., and Beckley, B.D., "A Global Mean Sea Surface Based Upon GEOS-3 and SEASAT Altimeter Data", J. Geophys. Res., in press, 1992.
 
Mather, R., Lerch, F.J., Rizos, C., Masters, E., and Hirsch, B.,
"Dynamic Sea Surface Topography from GEOS-3 Altimetry: Determination of Some Dominant Parameters", The Use of Artificial Satellites for Geodesy and Geodynamics, pp. 448-477, 1979.
 
Mather, R.S., Lerch, F.J., Rizos, C., Masters, E.G., and Hirsch, B., "Determination of Some Dominant Parameters of Global Dynamic Sea Surface Topography from GEOS-3 Altimetry", - NASA TM-79558, 40pp, 1978.
 
Rapp, R. H., "Gravity anomalies and sea surface heights derived from a combined GEOS 3/Seasat altimeter data set," J. Geophys. Res., 91, 4867-4876, 1986.
 
Schutz, B.E., Tapley, B.D., Ries, J.C., and Eanes, R.J., "Polar Motion Results From GEOS-3 Laser Ranging", J. Geophys. Res., 84(B8), July 30, 1979.