Spacecraft
The spacecraft were manufactured by Astrium of Germany, using its "Flexbus" platform. The microwave RF systems, and attitude determination and control system algorithms were provided by Space Systems/Loral. The star cameras used to measure the spacecraft attitude were provided by Technical University of Denmark. The instrument computer along with a highly precise BlackJack GPS receiver and digital signal processing system has been provided by JPL in Pasadena. The highly precise accelerometer that is needed to separate atmospheric and solar wind effects from the gravitation data was manufactured by ONERA.
Read more about this topic: Gravity Recovery And Climate Experiment