In an initiative to observe our climate with greater precision, the Sentinel-6B Earth-monitoring satellite was launched recently. This project is backed by a global alliance of space agencies, spearheaded by NASA. The coalition also includes the European Space Agency (ESA), the European Organization for the Exploration of Meteorological Satellites (EUMETSAT), and the National Oceanic and Atmospheric Administration (NOAA). The mission was set to launch on November 17, 2025, from Vandenberg Space Force Base in California, and the launch proceeded as intended.
Sentinel-6B has taken over the duties of its predecessor, Sentinel-6 Michael Freilich, which was deployed in 2020. Thanks to these initiatives, scientists are able to persist in documenting global sea-level shifts continuously. The heating oceans and melting ice are causing global sea levels to rise at a concerning pace. Monitoring these variations is vital because even slight changes can affect and amplify storm surges. Coastal flooding events are also worsening, putting communities in these areas at ongoing risk. The goal of Sentinel-6 and its successor, Sentinel-6B, is to serve as an essential instrument in protecting our shorelines and combating climate change.
Track sea levels from space
The mission of Sentinel-6B (also referred to as Jason-CS B) aims to continue and improve upon the over 30-year record of global sea-level data. It is founded on international collaboration that has become crucial for observing our evolving planet. This partnership has combined scientific knowledge, technical resources, and decades of experience in ocean observation. The collaborating agencies have devised a mission that no single country could accomplish alone. With the launch finalized, Sentinel-6B now pairs with its predecessor, Sentinel-6 Michael Freilich. The two satellites will operate together in tandem for an estimated year.
During this transition period, both satellites will function concurrently on nearly identical ground tracks. This will enable scientists and engineers on the ground to calibrate and validate their measurement systems. Thus, the data stream’s continuity will be assured. The new satellite’s data must integrate smoothly with the existing baseline.
“Grasping tidal variations down to the inch is vital in safeguarding our usage of the oceans daily on Earth,” stated Nicky Fox, associate administrator for NASA’s Science Mission Directorate, in a NASA press release. She highlighted that Sentinel-6B will build on the work of Sentinel-6 Michael Freilich by supplying measurements that enhance the forecasts relied on by coastal communities. The information collected by this mission will also play a role in ensuring the safe return of astronauts, including crews from NASA’s forthcoming Artemis lunar missions.
Once the transition is complete, Sentinel-6B will become the premier satellite globally for sea level measurements. It will uphold the lengthy record of observations that researchers depend on for climate studies, predictions, and planning. EUMETSAT is currently managing the satellite’s operations and will conduct the mission alongside its European and U.S. collaborators.
Additional information about Sentinel-6B
Sentinel-6B is a direct continuation of the work established by its predecessor, Sentinel-6 Michael Freilich. Nevertheless, the updated model is enhanced, enabling it to provide greater reliability in global sea level measurements. Among the key upgrades is the prolonged transition phase, though that is not the only improvement.
Sentinel-6B utilizes the same high-precision Poseidon-4 radar altimeter technology as its predecessor. It can measure sea-surface height with centimeter-level accuracy. Additionally, it features an advanced atmospheric microwave radiometer for climate (AMR-C) to compensate for atmospheric water vapor. Furthermore, it incorporates improved orbit-determination technology, which includes Global Navigation Satellite System (GNSS) receivers, Doppler Orbitography Radio-positioning Integrated by Satellite (DORIS), and a laser retroreflector. This allows it to achieve superior positioning and enhance sea-level measurements. It will cover approximately 90% of Earth’s ice-free oceans every 10 days.
Sentinel-6B is not merely a continuation of the mission. It represents a significant upgrade that secures nearly three decades of data and bolsters informed decision-making regarding our planet’s changing oceans, rising sea levels, and melting ice shelves.
