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Ocean Surface Topography from Space
Jason-CS (Sentinel-6)

Jason-CS/Sentinel-6 Launch Plan: 2020 and 2025

Mission Summary

Artists concept of the Sentinel-6

The Jason Continuity of Service (Jason-CS) mission on the Sentinel-6 spacecraft is an international partnership between the U.S. and Europe. Jason-CS/Sentinel-6 includes two identical satellites scheduled to launch in 2020 (satellite A) and 2025 (satellite B). These satellites will carry the record of sea level change – used by agencies, oceanographers, climate scientists, and many more – into its fourth decade.

Jason-CS/Sentinel-6 will be a “game changer” because it will ensure continuity of sea level observations for at least a decade. Like their predecessors, these satellites will provide ongoing measurements of global sea level rise – one of the most important impacts of human-caused climate change. The data will also support operational oceanography, improving forecasts of ocean currents as well as wind and wave conditions. In addition, it will help to improve forecasts of weather conditions likely to prevail two to four weeks ahead (e.g., hurricane intensity forecasting) and in the next season (e.g., El Niño, La Niña). Jason-CS/Sentinel-6 will also aid weather prediction through a new experiment: Global Navigation Satellite System Radio Occultation (GNSS-RO). Watching GNSS satellites as they disappear over the horizon will provide detailed information about the layers in the atmosphere. This information will contribute to computer models that predict the weather and enhance forecasting capabilities.

Since 1992, high-precision satellite altimeters have been essential to help scientists understand how the ocean stores and redistributes heat, water, and carbon in the climate system. The Jason-CS/Sentinel-6 satellites will extend this legacy through at least 2030, providing a nearly 40-year record of sea level rise, along with changes in ocean currents and conditions.

Artists concept of the Sentinel-6.

The satellites will carry several instruments (JPG, 100 KB) to support science goals. A Radar Altimeter will bounce signals off the ocean surface. Sea surface height will be determined based on the time it takes each pulse to travel from the satellite to the ocean and back again. An Advanced Microwave Radiometer will retrieve the amount of water vapor between the satellite and ocean, which affects the travel speed of radar pulses. Radio Occultation Antennas will measure the delay of radio signals between Jason-CS and global navigation satellites as they slice through different layers of the atmosphere. Other onboard instruments will be used to precisely determine the satellite’s position (DORIS, Laser Retroreflector Array), downlink data (S-band and X-band antennas), and supply power (Solar Array).


  • NASA
    • Advanced Microwave Radiometer (AMR-C) and its data processor;
    • GNSS-RO instruments and associated data products;
    • Laser Retroreflector Array (LRA);
    • Spacecraft integration and test activity support;
    • Launch services; and
    • Launch and Early Orbit Phase (LEOP), satellite commissioning, and routine operations support.
Image of sealevel data.
  • European Space Agency (ESA)
    • Sentinel-6 A and B satellites;
    • Radar Altimeter;
    • GNSS-Precise Orbit Determination (POD) and DORIS receivers;
    • Altimeter ground data processor;
    • Command and control of spacecraft though LEOP phases; and
    • Satellite in-orbit verification, commissioning, and routine operations support.
  • Centre national d'études spatiales (CNES)
    • Precise orbit determination using GNSS-POD, DORIS and 60 associated ground stations; and
    • Assessment of mission performance.
  • European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT)
    • Overall system design activities coordination;
    • Ground segment development, implementation, and validation;
    • Command and control of operating satellites after LEOP phases;
    • Operational altimetry data processor;
    • Near-real-time and offline data processing; and
    • Dissemination of altimetry and other data products.
  • National Oceanic and Atmospheric Administration (NOAA)
    • U.S. ground stations for telemetry data downlink and spacecraft commanding; and
    • Dissemination of near-real-time data products.

NASA, ESA, and EUMETSAT will provide mission management and system engineering support. NASA and EUMETSAT will be responsible for long-term archives of altimetry data products. All partners will be involved with the selection of science investigators.


Jason-CS original content:

Artists concept of the Sentinel-6

Jason-CS/Sentinel-6 Launch Plan: 2020

Mission Summary

The Jason-CS mission (on the Sentinel-6 spacecraft) is an international partnership between NASA, NOAA, the European Space Agency (ESA), and EUMETSAT.

Jason-CS will continue the high precision ocean altimetry measurements of the Jason-series satellites into the 2020–2030 time-frame using two successive, identical satellites, Sentinel-6A and Sentinel-6B.

A secondary objective of Jason-CS is to collect high resolution vertical profiles of temperature, using the GNSS Radio-Occultation sounding technique, to assess temperature changes in the troposphere and stratosphere and to support Numerical Weather Prediction.


  • NASA will provide the launch services for both Jason-CS satellites, a radio-occultation instrument based on a Tri-G receiver, AMR-C Microwave radiometer, and the same Laser Reflector Array as on the Jason-3 satellite, as well as and ground segment support. NASA will also contribute to the spacecraft operations and data processing.
  • EUMETSAT is leading the system definition and is responsible for the ground segment development; operations preparation and operations of both satellites, and will co-fund the second satellite, together with the European Commission (EC).
  • ESA is responsible for the development of the first satellite; the prototype processors; delivery of the LEOP services, and the procurement of the second satellite on behalf of EUMETSAT and the EC.
  • The EC co-funds the second satellite with EUMETSAT and funds the operations of Jason-3 and both Sentinel-6 satellites, including the LEOP service for the second satellite.
  • NOAA provides U.S. ground stations for data down links.

Artists concept of the Sentinel-6.

  • Measurements of ocean topography, being the equivalent of surface pressure in the atmosphere, are enabling numerical prediction of the three-dimensional ocean, which is a prerequisite to the development of operational oceanography in synergy with marine meteorology.
  • The development of operational oceanography is, in turn, necessary to improve forecasts of the weather conditions likely to prevail two to four weeks ahead (monthly forecasts), e.g. heat waves or sustained heavy downpours, and in the next seasons (seasonal forecasts) e.g. a cold winter or a hot summer, as a result of the sustained influence of the ocean on the atmosphere.
  • Variations of sea level (some mm per year) in our changing climate can only be monitored on global scale by HPOA observations, and ocean surface topography measurements are essential to understand how the ocean stores and redistributes heat, water and carbon in the climate system.

Additional Information

Image of sealevel data.

Scientific Instrument(s)

  • Radar altimeter; developed by ESA, based on the Sentinel-3 SARL instrument, with a design adopted to allow the interleaved mode combining SAR and LRM modes;
  • AMR-C Microwave radiometer; provided by NASA;
  • GNSS Precise Orbit Determination (POD) Receiver; developed by ESA and derived from the GNSS Receiver on Sentinel-3;
  • Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) Receiver; same as on Jason-3 and Sentinel-3; provided by CNES
  • Laser Reflector Array (LRA); same as on Jason-3, provided by NASA;
  • GNSS-Radio-occultation (GNSS-RO) instrument; based on a Tri-G receiver, provided by NASA.

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