The Sentinel-6B satellite lifted off aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California at 9:21pm (PST) on 16 November. NASA confirmed contact with a ground station in northern Canada at 10:54pm, around 90 minutes after launch, with all systems operating as expected.
“Understanding tidal patterns down to the inch is critical for how we use our oceans every day,” said Nicky Fox, NASA’s Science Mission Directorate associate administrator. “Sentinel-6B will extend the legacy of Sentinel-6 Michael Freilich by providing sea-level measurements that improve forecasts relied upon by communities and businesses. It will also support safe re-entry for returning astronauts, including future Artemis crews.”
The spacecraft will collect precise sea-level data at both global and local scales from low-Earth orbit, underpinning US flood forecasting tools used to safeguard coastal assets ranging from homes and ports to energy facilities. Sentinel-6B will eventually replace Sentinel-6 Michael Freilich – launched in 2020 – as the world’s reference satellite for sea-level measurement accuracy.
Sentinel-6B is the product of an international collaboration involving NASA, the European Space Agency (ESA), EUMETSAT, the US National Oceanic and Atmospheric Administration (NOAA), and the European Union’s Copernicus Earth-monitoring program.
“Partnership is essential for a mission like Sentinel-6,” ESA Earth Observation Programmes director Simonetta Cheli said. “This satellite continues the work of Sentinel-6 Michael Freilich and demonstrates what can be achieved when global agencies and industry work together. Sentinel-6B will continue delivering the high-precision data needed to understand climate change, protect our oceans and support coastal communities worldwide.”
Together, Sentinel-6B and its predecessor form the Copernicus Sentinel-6/Jason-CS mission – the latest chapter in a long-running series of ocean altimetry satellites dating back to the early 1990s.
Like the original Sentinel-6 satellite, Sentinel-6B will also gather data on wind speeds, wave heights, atmospheric temperature and humidity. Because warmer water expands and raises sea surface height, the satellite’s measurements allow scientists to identify warming regions of the ocean. When combined with other data sources, this information can improve marine weather forecasts and track conditions that fuel storm formation.
The data will also help monitor major ocean currents such as the Gulf Stream, where interactions with surrounding waters can create dangerous sea states – even for large commercial vessels.
“Sentinel-6B shows the value of NASA’s partnership missions in putting actionable information into the hands of decision makers,” said Karen St Germain, head of NASA’s earth science division. “Its observations will guide decisions vital to coastal communities, shipping and fishing industries, national security and emergency management.”
Once in operational orbit, Sentinel-6B will fly roughly 30 seconds behind Sentinel-6 Michael Freilich while their data is cross-calibrated. After that process, the earlier satellite will shift into a different orbit, and Sentinel-6B will assume the role of primary reference satellite. It will circle Earth about 13 times a day at an altitude of 1,336 kilometres.
“The satellite’s advanced instruments will measure around 90 per cent of the world’s oceans down to fractions of an inch,” said Dave Gallagher, director of NASA’s Jet Propulsion Laboratory. “It continues a vital dataset relied upon by the United States and an expanding global community.”