SpaceX Launches Sentinel-6B to Monitor Global Sea Levels

On November 17, 2025, SpaceX successfully launched the Sentinel-6B satellite from the Vandenberg Space Force Base in California. This mission marks the continuation of a significant partnership between NASA and European agencies aimed at monitoring long-term changes in sea levels, a critical indicator of climate change.

The Sentinel-6B, which follows the original Sentinel-6 satellite launched in November 2020, is part of a billion-dollar initiative designed to enhance understanding of our planet’s changing climate. The Falcon 9 rocket lifted off at 12:21 a.m. EST, deploying the satellite into an orbit approximately 830 miles above Earth.

Advanced Technology for Sea Level Monitoring

Equipped with cutting-edge cloud-penetrating radar, the Sentinel-6 satellites can measure sea levels with an accuracy of about one inch. They achieve this by timing how long it takes radar beams to bounce back from the ocean surface. The data obtained will also provide insights into wave heights and wind speeds.

This initiative builds on previous missions dating back to the early 1990s, which have created a continuous record of sea level data. This data has been interpreted as evidence of rising sea levels, attributed largely to human-induced global warming. Despite the significance of these findings, NASA’s pre-launch communications for Sentinel-6B notably refrained from using terms like “climate change” or “global warming.”

In a pre-launch briefing, Karen St. Germain, director of NASA’s Earth Science Division, emphasized the practical applications of the satellite’s data. She stated, “Sentinel 6B is the latest in a line of missions stretching over three decades, keeping an uninterrupted watch over our planet’s sea surface height.” St. Germain highlighted how this information is vital for navigation, flood predictions, and coastal infrastructure planning.

Collaboration and Broader Implications

The Sentinel-6 program is a collaborative effort involving NASA, the European Space Agency (ESA), the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), and the National Oceanic and Atmospheric Administration (NOAA). NASA’s contribution for both Sentinel-6 satellites is approximately $500 million, matched by European partners.

In addition to sea level measurements, Sentinel-6B will monitor atmospheric temperature and humidity, contributing to a broader understanding of climate dynamics. The satellite’s ability to gather data over 90 percent of the world’s oceans is crucial as it will inform strategies to address coastal erosion and the encroachment of saltwater into freshwater supplies.

The launch of Sentinel-6B marks a significant advancement in environmental monitoring, continuing a legacy of satellite missions dedicated to understanding Earth’s changing climate. As Craig Donlon, a project scientist with the ESA, noted prior to the first Sentinel-6 launch, “The greatest indicator of this Earth system imbalance is sea level rise.” Through these missions, scientists hope to gain deeper insights into the ongoing effects of climate change on our planet.