SpaceX Successfully Launches Sentinel-6B to Monitor Sea Levels

SpaceX has successfully launched the Sentinel-6B satellite, a collaborative project between NASA and European agencies, aimed at monitoring global sea levels. The Falcon 9 rocket lifted off from the Vandenberg Space Force Base in California on November 17, 2025, at 12:21 a.m. EST. This mission marks a significant advancement in efforts to track long-term changes in sea levels, a crucial indicator of climate change.

The Sentinel-6B satellite is the second in a series designed to provide continuous data on sea levels. Its predecessor, Sentinel-6, was launched in November 2020 and is named after NASA climate researcher Michael Freilich. Both satellites are equipped with advanced cloud-penetrating radar, allowing them to measure sea levels with an accuracy of approximately one inch. This technology enables the monitoring of wave heights and wind speeds from an altitude of 830 miles.

Long-Term Climate Monitoring Initiative

The Sentinel project builds on earlier missions that began in the 1990s, providing an uninterrupted stream of sea level data. This data is increasingly important as it indicates a steady rise in sea levels, often interpreted as evidence of global warming linked to human activities.

Notably, during a pre-launch briefing, NASA did not explicitly mention terms like “climate change” or “global warming,” a shift from previous communications. Karen St. Germain, the director of NASA’s Earth Science Division, emphasized the practical applications of the data instead of its implications for climate change. She stated that “Sentinel-6B is the latest in a line of missions stretching over three decades,” highlighting its role in improving public safety, urban planning, and protecting various interests along coastlines.

The data obtained from the Sentinel-6 satellites will aid in flood predictions and help manage coastal infrastructure, real estate, and energy storage sites. It will also provide insights into coastal erosion and the encroachment of saltwater into freshwater supplies used for agriculture and drinking.

Launch and Operational Overview

The launch of Sentinel-6B proceeded smoothly, with the Falcon 9 rocket successfully navigating through the dense lower atmosphere before the first stage returned to a landing pad at Vandenberg. The upper stage performed two engine firings before deploying the 2,600-pound satellite into its designated orbit.

The solar-powered Sentinel-6B will orbit Earth every 112 minutes, covering 90 percent of the world’s oceans from latitudes of 66 degrees north to south. In addition to sea level measurements, the satellite will monitor temperature and humidity in both the lower atmosphere and the stratosphere, using technology that assesses atmospheric effects on navigation satellite signals.

Craig Donlon, a project scientist with the European Space Agency, previously noted the urgency of monitoring sea levels. He pointed out that industrialization has disrupted the Earth’s dynamic balance, leading to observable changes in various measurements. According to Donlon, “the greatest indicator of this Earth system imbalance is sea level rise.”

The Sentinel-6 missions represent a collaboration between NASA, the European Space Agency, the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), and the National Oceanic and Atmospheric Administration. NASA’s investment in both Sentinel-6 satellites is approximately $500 million, matched by similar contributions from European partners.

As the world grapples with the implications of climate change, the data produced by Sentinel-6B and its predecessor will be vital for understanding and addressing the challenges posed by rising sea levels.