The GEOS ( Geostationary Earth Orbit Satellite ) program of the European Space Agency included the first satellites in geostationary orbit that were used exclusively for scientific purposes. In the parlance of NASA , which was responsible for the launch of the satellites, these satellites are also referred to as ESA-GEOS in order to distinguish them from the NASA GEOS program of the same name .
The task of the satellites was to measure the electric and magnetic fields , the plasma - magnetic field interactions and the energy and angular distribution of the charged particles ( electrons and ions ) in the geostationary orbit .
The satellites had a cylindrical design with a height of 1.32 m. Without fuel, they each weighed 274 kg. In orbit they unfolded four 2.5 m long booms, two 20 m long cable booms and two 3 m long lockable booms for the various sensors. To prevent electrostatic charges , 96% of the satellite surface was electrically conductive.
Both satellites were identical, apart from minor modifications to some experiments.
Satellites in the GEOS program
- GEOS 1 (before launch, GEOS A) was launched from Cape Canaveral on April 20, 1977 with a Delta-2914 rocket. A failure of the Delta rocket means that the geostationary orbit could not be reached. Some of the experiments could also be carried out from the highly elliptical orbit with a 12-hour orbit, between 2682 and 38,475 km altitude at a 26.6 ° orbit inclination.
- GEOS 2 (before launch, GEOS B) was successfully launched from Cape Canaveral on July 14, 1978 with a Delta-2914 rocket and then positioned at 37 ° East above the equator.