German Spaceborne Sar Missions

This paper provides an overview of the German spaceborne radar program starting with the X-band synthetic aperture radar (SAR) instrument on board the Shuttle Imaging Radar missions (SIR-C/X-SAR) in 1994, followed by the Shuttle Radar Topography Mission (SRTM) in 2000. The German national satellite radar program began in 2007 with the launch of the satellite TerraSAR-X which is providing since then high-resolution X-band images for scientific, commercial and governmental applications. TanDEM-X, an almost identical twin of TerraSAR-X, was launched in 2010. Both satellites fly in close formation to form the first bistatic, single-pass interferometric spaceborne SAR system. A global, highresolution digital elevation model (DEM) of the Earth's surface with unprecedented accuracy has been generated and made available for a broad community since 2016. A second edition of global DEM, denoted as Change DEM, will be available in 2022. Both satellites are still fully functional and have enough consumables for several additional years of operation. The paper concludes with an overview of the innovative concepts, technologies, imaging techniques and applications planned for the future national SAR missions Tandem-L and HRWS.