TerraSAR-X is an imaging radar Earth observation satellite, a joint venture being carried out under a public-private-partnership between the German Aerospace Center (DLR) and EADS Astrium.

Depending on the desired application, one of four different processing levels is selected: TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurements) is a second, similar spacecraft launched on 21 June 2010 from Baikonur Cosmodrome in Kazakhstan.

With higher accuracy, coverage and quality – WorldDEM is a consistent DEM of the Earth's land surface is envisaged to be acquired and generated within three years after launch.

Available from 2014, WorldDEM is to feature a vertical accuracy of 2 m (relative) and 10 m (absolute), within a horizontal raster of approximately 12×12 square meters, slightly varying depending on the geographic latitude.

Early radar satellite techniques were altimetry (measuring height over sea level), NASA's SEASAT (launched in 1978), study of waves/wind or soil data.

[11] The new-quality data records, as provided by TerraSAR-X, will offer a vast amount of new research incentives, for instance in ecology, geology, hydrology and oceanography.