Sentinel-6B Satellite Successfully Launched to Continue Global Sea Level Monitoring

The Sentinel-6B satellite successfully launched on November 16, 2025, at 9:21 p.m. PST (12:21 a.m. EST on November 17, 2025), from Space Launch Complex 4 East at Vandenberg Space Force Base in California. The deployment, executed via a SpaceX Falcon 9 rocket, secures the continuation of long-term global sea level data collection, a critical component in tracking climate change indicators.

This mission represents the second of two identical spacecraft for the Copernicus Sentinel-6/Jason-CS (Continuity of Service) endeavor, highlighting extensive international partnership. Key collaborators include NASA, the European Space Agency (ESA), EUMETSAT, and the National Oceanic and Atmospheric Administration (NOAA). The European Commission provided financial support, while the French space agency, CNES, contributed technical expertise to the project. This sustained effort maintains the accuracy of the global sea-surface height record, which has been continuously monitored since the TOPEX/Poseidon mission began in 1992.

Sentinel-6B will operate in tandem with its predecessor, Sentinel-6 Michael Freilich, which launched in November 2020, for a cross-calibration period lasting approximately one year. Following this process, Sentinel-6B will assume the primary reference altimetry role, ensuring data continuity through at least 2030 and potentially extending the comprehensive record to nearly forty years. The satellite, approximately 19.1 feet long and weighing around 2,600 pounds with propellant, is designed for a nominal operational lifetime of about five and a half years in Low Earth Orbit.

The spacecraft carries sophisticated scientific instrumentation, including a radar altimetry instrument capable of measuring sea-surface height with centimeter-level precision. It is also equipped with an Advanced Microwave Radiometer (AMR-C) from NASA to correct for atmospheric water vapor effects, and a Global Navigation Satellite System for Radio Occultation (GNSS-RO) package. This instrumentation allows the satellite to map sea levels across roughly 90% of Earth's ocean, providing data vital for refining hurricane intensity forecasts, securing coastal infrastructure, and optimizing commercial shipping routes.

The successful orbital insertion of Sentinel-6B is a significant advancement for operational oceanography and climate modeling. The consistent stream of high-accuracy data underpins global mean sea level estimates and regional variability analyses, directly informing decision-making for coastal cities facing increased flood risks. Furthermore, the data supports broader scientific objectives, including refining atmospheric models used by NASA in operations related to space exploration.