In 1992, TOPEX/Poseidon was the first ocean-observing satellite to be placed in a highly inclined orbit at an altitude of 1,336 km, covering 95% of the globe’s ice-free oceans every 10 days. In 2001, Jason-1 and then in 2008 Jason-2 were positioned in the same orbit. Jason-3 is set to join them in 2016.

Together, these French-U.S. satellites have accumulated an exceptional data record on ocean topography, enabling scientists to track the peaks and troughs generated by ocean currents and to precisely determine sea level rise. To pursue this mission crucial to our ability to understand the processes fuelling global warming, the Jason-CS-A/Sentinel-6A and Jason-CS-B/Sentinel-6B satellites will be launched in 2020 and 2026. They will be placed in the same orbit as their predecessors and carry the same instruments to assure the data consistency so vital to scientific study.

The Jason-CS mission (CS for Continuity of Service) is part of the European Copernicus programme and the MyOcean operational oceanography project funded by the European Commission. This mission is a cooperation between ESA, the European Commission and Eumetsat. The US is also a key partner in the mission, with NASA and NOAA playing a role in the launch, US operations and provision of a radiometer, a GNSS-RO receiver and a Laser Retroreflector Array. CNES is another key mission partner with the task of precisely determining the satellite’s orbit with the DORIS instrument and 60 associated ground stations, and the GNSS-POD receiver. It is also in charge of assessing the mission’s performance.