Sentinel-6B enters service, carrying the satellite sea-level record into the 2030s

The Copernicus Sentinel-6B satellite entered operational service on October 30, 2026, and its data are now available to users, said EUMETSAT, Europe's meteorological satellite agency, which operates it on behalf of the European Commission. The satellite extends measurements of global sea level that go back to 1992 and, EUMETSAT says, will keep the series going into the 2030s.

Sentinel-6B is the second satellite of the Sentinel-6 mission and launched from Vandenberg Space Force Base in California in November 2025. Since December 2025 it has flown in tandem with its twin, Sentinel-6 Michael Freilich, launched in November 2020, at an altitude of 1,336 km (830 miles) and 30 seconds apart, which lets scientists check the new satellite's measurements against the old one's. EUMETSAT expects Sentinel-6B to become the internationally agreed reference within months, which means the measurements of other sea-level satellites will be calibrated against its own. After that, Sentinel-6 Michael Freilich will shift to a different orbit, which ends the tandem flight and widens the pair's coverage of the oceans.

What the record shows

Global average sea level is up by more than 11.5 cm (about 4.5 inches) since December 1992, according to EUMETSAT, and the rise is speeding up. The rise comes from melting glaciers and ice sheets and from ocean warming, which makes seawater expand.

Together the twins can cover up to 95% of the ice-free ocean. Besides sea level, they measure ocean currents, wave height and wind speed, and the height of rivers and lakes, while a radio occultation instrument records the temperature and water vapor of the atmosphere.

Around 900 million people live in low-lying coastal areas worldwide, and weather and ocean services across our Member States rely on Sentinel-6 data to protect people, infrastructure and ecosystems.

From forecasts to climate records

Within hours of a measurement, EUMETSAT says, weather services are using it in their models, for example to predict heavy seas in winter storms or how much a hurricane will intensify. Over longer periods, the sea-level record feeds seasonal outlooks, including forecasts of El Niño and La Niña. EUMETSAT runs the satellites 24 hours a day and gets their data to users in about three hours.

NASA's Jet Propulsion Laboratory said in September that Sentinel-6B had begun delivering low-latency data that could be used for weather prediction on July 15. Deirdre Byrne, a NOAA oceanographer who oversees the agency's Satellite Ocean Heat Content Suite, a hurricane forecasting algorithm, planned to start adding Sentinel-6 ocean height data to it by the end of the year, JPL reported.

A record built by six satellites

The mission is the latest in a line of joint European and U.S. altimetry satellites that began with TOPEX/Poseidon and continued with the Jason series. EUMETSAT works on Sentinel-6B with ESA, NASA and NOAA, and the French space agency CNES supports the mission. NASA's JPL contributed three of the science instruments on each Sentinel-6 satellite, and NASA provided the launch services.

EUMETSAT's director-general, Phil Evans, said the satellite's data give a fuller view of the oceans when combined with altimetry from the Copernicus Sentinel-3 satellites, and support daily weather forecasts together with wind and atmospheric measurements from EUMETSAT's Metop satellites.