Precise orbit predictions are service products to support Satellite Laser Ranging (SLR), pre-processing of mission data and mission operations. In all cases it is necessary to know the position of the satellite at some time in the future with a dedicated accuracy depending on the application. GFZ is delivering orbit prediction products for these purposes for the Low Earth Orbiters (LEOs) GRACE-A and -B, TerraSAR-X and TanDEM-X. In the past we did this as well for ERS-1, ERS-2, METEOR-3, MIR, GFZ-1, and CHAMP. The orbit predictions highly contribute to the success of these missions. E.g. SLR observations play an important role in Precise Orbit Determination (POD), predicted orbits (naturally not the most precise ones but readily available in real-time) are needed for reduction of space-borne accelerometer data, and orbit predictions are input for scheduling downloads of satellite data and commanding of satellite instruments.

The most demanding application of the orbit predictions is the steering of the laser tracking ground stations of the International Laser Ranging Service (ILRS). For the acquisition of SLR data the required accuracy for LEOs is about 70 m in along-track direction, equivalent to a 10-ms bias of the time the satellite becomes visible over a station (i.e. the satellite is too early or too late), shortly called time bias. The accuracy of the predicted orbits is continuously being monitored. The predicted orbits are compared to Rapid Science Orbits (RSO) that act as highly accurate (a few centimetres) reference orbits.