The twin GRACE satellites were launched on March 17, 2002. Since that time, the GRACE Science Data System (SDS) has produced and distributed estimates of the Earth gravity field on an ongoing basis. These estimates, in conjunction with other data and models, have provided observations of terrestrial water storage changes, ice-mass variations, ocean bottom pressure changes and sea-level variations. This portal, together with PODAAC, is responsible for the distribution of the data and documentation for the GRACE project.
GRACE is a joint partnership between the National Aeronautics and Space Administration (NASA) in the United States and Deutsches Zentrum fuer Luft und Raumfahrt (DLR) in Germany. Prof. Byron Tapley of the University of Texas Center for Space Research (UTCSR) is the Principal Investigator (PI), and Dr.-Ing. Frank Flechtner of the GeoForschungsZentrum (GFZ) Potsdam is the Co-Principal Investigator (Co-PI).