Copernicus Sentinel Mission at C- and L-Band: Current Status and Future Perspectives

In the last ten years, ESA's Earth Observation (EO) program has been based on three main pillars, i.e. Copernicus, Meteorology and Earth Science Explorer and on some crosscutting activities covering international cooperation and preservation of historical data. In the framework of the Copernicus program, the Sentinel-1 mission is the workhorse for acquiring systematically and providing routinely a large volume of C-band SAR data to the Copernicus services and the global scientific and commercial user community. As part of the Copernicus expansion, ESA completed the study phase for an L-band SAR mission (ROSE-L) last October 2019 and issued the corresponding Request for Proposal for the development of two spacecraft. On the other hand, the availability of high-resolution X-band data is ensured through national European SAR missions, such as TerraSAR-X, Cosmo-SkyMed and PAZ, which are referred to as Copernicus Contributing Missions. L-band SAR data are required for applications, such as surface deformation mapping, monitoring of cryosphere dynamics, sea-ice classification and land cover mapping, among others. As such, L-band data provide complementary information to C- and X-band data. Besides ESA's ROSE-L, Germany is perusing the implementation of the proposed Tandem-L mission, at national level. Recently, disruptive NewSpace smallSat SAR companies have emerged on the EO market. This has triggered discussions on whether or to what extent smallSats can eventually replace or complement large institutional SAR missions. In this paper we provide the overview of the evolution of the Copernicus SAR Space Component: the Sentinel-1 Space Segment and the Spacecraft development status, the ROSE-L development approach and we also discuss the challenges for the evolution. its objectives and implementation, the systematic data acquisition strategy including coverage and revisit frequency, and the end-to-end SAR performance