The main goal of the TerraSAR-X Add-On for Digital Elevation Measurements (TanDEM-X) mission is the generation of a global digital elevation model (DEM) of unprecedented accuracy and coverage. The global TanDEM-X DEM product became available in 2016, surpassed all expectations, and became a reference for a wide range of Earth science, commercial, and geospatial applications. In addition, new information products, such as DEM change maps (DCMs), have been developed and are available to the geoscience and remote sensing community. Beyond the operational products, new science applications have been demonstrated and are summarized in this article, along with experimental data acquisitions. This article also aims to provide an overview of science activities with TanDEM-X data and science data acquisitions planned for the coming years.

This paper presents investigations on a one year time series of crossing orbit differential interferometry SAR acquisitions with a 1-, 5- and 6-days temporal baseline. The conditions for crossing orbit interferometry are briefly discussed as the requirement of a common ground spectrum has to be satisfied. The uniquely short revisit times give the opportunity to perform interferometry on a glacier area, i.e. the Ronne ice-shelf, in X-band. The coherence results over one year as well as surface velocity measurements are shown and discussed.