general navigation structure general satellite info ilrs support retroreflector info center of mass site performance info


Jump to: Mission Objectives, Mission Instrumentation, Mission Parameters, Additional Information

Mission Photos:

Courtesy of GFZ

Mission Objectives:

GeoForschungsZentrum (GFZ)-1 is the first satellite mission designed and funded by the GeoForschungsZentrum Potsdam, Germany. The mission objectives of GFZ-1 are to determine variations in the rotational characteristics of the earth and to measurement changes in the earth's gravity field. For the high resolution determination of the parameters of the gravity field the satellite must be launched into the lowest possible orbit. At its altitude of 400 kilometers, GFZ-1 will be the lowest geodynamic satellite to be ranged to by lasers and it is anticipated that it will lead to a significant improvement in the modeling of the gravity field. As the vehicle's orbit decays, the satellite's orbital motion will also be used calculate atmospheric densities.

The satellite was built and launched by Russia. GFZ-1 was transported to the MIR Station aboard a Russian PROGRESS spacecraft and from there put into a low earth orbit in April 1995.

Mission Instrumentation:

GFZ-1 is a passive geodetic satellite which only has one instrument, the retroreflector array.

Mission Parameters:
Sponsor: GFZ (Germany)
Expected Life: 5 years
Primary Applications: time varying gravity field
COSPAR ID: 8601795
SIC Code: 8001
Satellite Catalog (NORAD) Number: 23558
Launch Date: April 19, 1995
RRA Diameter: 21 cm
RRA Shape: sphere
Reflectors: 60 corner cubes
Orbit: circular
Inclination: 51.6 degrees
Eccentricity: 0.000
Perigee: 398 km (initial)
Period: 92 minutes
Weight: 20 kg

Additional Information:

Web sites:


  • Chen, Z. and Koenig, R., "The GFZ/D-PAF orbit Prediction System with Emphasis on the Low Flyer GFZ-1", Proc. of the 10th International Workshop on Laser Ranging Instrumentation, Shanghai Observatory, Chinese Academy of Sciences, Shanghai, China, November 11-15, p. 489, 1996.
  • Koenig, R., Bode, A., Chen, Z., Grunwaldt, L., Neubert, R., Reigber, Ch., and Schwintzer, P., "The GFZ-1 Mission: Design", Operations and First Results. Scientific Technical Report STR96/09, GFZ Potsdam, 1996.
  • Koenig, R., Bode, A., Chen, Z., and Reigber, Ch., "Surface Forces Parametrization of GFZ-1 Orbits and Gravity Field Recovery", Advances in Space Research, Vol. 19, No. 11, 1677-1680, 1997.
  • Koenig, R., Chen, Z., Reigber, and C., Schwintzer, P., "Improvement in global gravity field recovery using GFZ-1 satellite laser tracking data", Journal of Geodesy, 73, 8, p. 398-406, 1999.
  • Koenig, R., Schwintzer, P., Bode, A., and Reigber, Ch.,"GFZ-1, A Small Laser Satellite Mission for Gravity Field Model Improvement", Geophysical Research Letters 23, No. 22, 3143-3146, 1996.
  • Koenig, R., and Massmann, F.H.,"The GFZ-1 Mission", Satellite Laser Ranging Newsletter, SLR/LLR Subcommission of the CSTG (International Coordination of Space Techniques for Geodesy and Geodynamics), Mai 1996, p. 16, Goddard Space Flight Center, NASA, 1996.
  • Koenig, R., and Reigber, Ch., "GFZ-1 Mission Operations and Performance", In: IAA Symposium on Small Satellites for Earth Observation, November 1996, Berlin, Symposium Digest, pp. 208-211, 1996.
  • Konig, R., and Chen, A., "Probable Qualities of GFZ-1 Orbit Predictions", Proc. of the 9th International Workshop on Laser Ranging Instrumentation, Australian Government Publishing Service, Canberra, p . 371, 1994.
  • Reigber, Ch., and Konig, R., "Gravity and Atmosphere Model Aspects by the Low Altitude Target GFZ-1", Proc. of the 9th International Workshop on Laser Ranging Instrumentation, Australian Government Publishing Service, Canberra, p . 22, 1994.