MULTIMISSION RAW DATA CENTER FOR GRACE

Abstract

By means of the small satellite mission GRACE (Gravity Recovery and Climate Experiment), a joint project between the National Aeronautics and Space Administration (NASA) and the Deutsches Zentrum für Luft- und Raumfahrt (DLR), the provision of the global high-resolution models of the Earth's gravity field for a period of up to five years with unprecedented accuracy is aimed. An secondary science objective of the GRACE mission is to provide several hundred globally distributed profiles each day of excess delay or bending angle of the GPS measurements due to the ionosphere and atmosphere using limb sounding. GRACE was selected in 1997 as second mission in NASA's Earth System Science Pathfinder project (ESSP). DLR is responsible for the missions control of this pair of satellites as well as for data reception, archiving and distribution. After the successful launch on March, 17th from the Russian launch pad at Plesetsk the Russian Rockot-launcher brought the pair of satellites into a circular orbit of approximately 500 Kilometer altitude. Between the contact periods the acquired science data are transmitted(1 Mbit/s) to DLR’s ground stations at Neustrelitz and Weilheim. The Raw Data Center located in Neustrelitz has to process, archive and routinely distribute all received data to the mission control center(MOS) and to the scientific centers at University of Texas (Austin) and GFZ Potsdam under not negligible requirements relating to reliability and timeliness. To reach this objectives in a cost- effective manner a new DLR- developed Data and Information Management System (DIMS) is brought into action, which accompanies the whole product life cycle incl. robot archiving in a mission independent way. So this system is in use for a multitude of small satellite missions (CHAMP, BIRD, CORONAS) in parallel. All received raw data will be long term archived to make available this measured data of our earth for future generations. This contribution will give a small overview of the GRACE mission and will explain more in detail the Raw Data Center and its results after the first year of operation.