CHAMP

Challenging Minisatellite Payload (CHAMP) was a German satellite launched July 15, 2000 from Plesetsk, Russia and was used for atmospheric and ionospheric research, as well as other geoscientific applications, such as GPS radio occultation, gravity field determination, and studying the Earth's magnetic field. CHAMP was managed by GeoForschungsZentrum (GFZ) Potsdam. The spacecraft is the first application of Astrium's "Flexbus" platform; GRACE was the second. A heavily modified version flew as the GOCE mission. Spacecraft instruments An onboard BlackJack Global Positioning System (GPS) Flight Receiver, provided by JPL, enables the use of satellite to satellite tracking for vehicle positioning. To remove the effect of external, non-gravitational forces (e.g., atmospheric drag, solar radiation pressure) the satellite features an internal 3-axis STAR accelerometer. Independent verification of orbital position is enabled by a passive Laser Retro Reflector (LRR), which also enables calibration of the principal positioning via laser ranging. Spacecraft attitude is measured using Advanced Stellar Compass (ASC) supplied by Technical University of Denmark.