GRACE - Gravity Recovery And Climate Experiment

The GRACE mission is a joint German-American project. The primary objective of the GRACE mission was to obtain accurate global models for the mean and time variable components of the earth´s gravity field. This goal was achieved by measurements of the inter-satellite range between 2 co-planar, low altitude near-polar orbiting satellites. In addition, each satellite carried a high accuracy accelerometer and a geodetic qualified GPS receiver to perform precise orbit determination, recover gravity data and to estimate the gravity field. The secondary task of the GRACE mission was to keep a daily record of several hundred globally distributed profiles of the delay or inclination angle of GPS measurements. Both can be converted into a total electron or refractivity by applying Atmospheric- and Ionospheric-Profiling. The German Space Operations Center configured the Ground Operations System and prepared and executed the GRACE mission operations.