SpaceX Sends Sentinel-6B to Orbit for Precision Sea-Level Tracking

SpaceX launched the ocean-monitoring satellite Sentinel-6B on November 17, 2025, at Vandenberg Space Force Base, California. Sentinel-6B will collect high-precision data on the sea-surface height in order to monitor the increase in ocean level within an extension of about forty years of consecutive monitoring of sea level. Sentinel-6B is part of the Copernicus climate program of Europe and is based on a twin satellite, which was launched in 2020. The launch was also significant since it was the 500th orbital launch by SpaceX to use a reflown Falcon 9 first stage.

Reusable Rocket Launch

According to a Space.com report, the Falcon 9 rocket took off at 12:21 a.m. carrying Sentinel-6B to orbit. Its first-stage booster—flying for the third time—landed back at Vandenberg nine minutes after launch. Fifty-seven minutes after launch, the Falcon 9's upper stage deployed Sentinel-6B into its target orbit. The 1,440-kilogram satellite will undergo checkout tests before beginning its science missions.

Sentinel-6B and Sea-Level Science

Sentinel-6B is a U.S.-European satellite that functions as a satellite in the Copernicus climate program in Europe. It has a radar altimeter and microwave radiometer to map sea-surface height in the entire world. According to NASA, the changes in sea level may be detected with excellent precision to approximately one inch (2.5 cm) over approximately 90 percent of the oceans. Such data will be the continuation of a decades-long record of sea levels. Within the first year, Sentinel-6B will be monitoring with its twin (the 2020 Sentinel-6 satellite) so that the instruments can be cross-calibrated even further to obtain even more precise results.