Sentinel-6B Launched: New Guardian of Earth’s Oceans Begins Its Mission

A new guardian of our oceans has officially taken its place in orbit. The Copernicus Sentinel-6B satellite is now circling Earth, ready to continue a decades-long mission to precisely monitor global sea-level rise — one of the clearest indicators of climate change.

Following in the footsteps of its predecessor, Sentinel-6 Michael Freilich, the newly launched satellite carries cutting-edge radar altimetry technology to extend the continuous sea-surface height record that began in the early 1990s. These measurements are essential for understanding rising seas, shaping climate policy, and protecting millions of people living in coastal regions around the world.

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Successful Launch from California

Sentinel-6B lifted off on 17 November at 06:21 CET aboard a SpaceX Falcon 9 rocket from Vandenberg Space Force Base, California.
Just under an hour after launch, the satellite was successfully placed into orbit. At 07:54 CET, ESA’s European Space Operations Centre in Germany received the first crucial signal via the Inuvik ground station in Canada — confirming that the spacecraft is healthy and operating as expected.

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Carrying Forward a Global Climate Legacy

Launched in November 2020, Sentinel-6 Michael Freilich has been the world’s primary reference mission for satellite sea-surface height measurements. Sentinel-6B will now continue that legacy.

The sea-level monitoring record began with the Topex-Poseidon satellite in the early 1990s, followed by the Jason series of missions. Together, they have created one of the most valuable long-term climate datasets ever produced.

With sea-level rise now a major global concern, the Sentinel-6 mission has become the gold standard for high-precision ocean height measurements.

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A Model of International Collaboration

Although Sentinel-6 is part of the European Union's Copernicus Programme, it represents a rare level of global cooperation. The mission brings together:

• European Commission

• ESA (European Space Agency)

• NASA

• Eumetsat

• NOAA

• CNES (French Space Agency)

ESA’s Director of Earth Observation Programmes, Simonetta Cheli, praised the teamwork behind the mission, saying:

“Collaboration between partners is key to a mission such as Sentinel-6. This achievement shows what can be accomplished when international agencies and industries work together toward a shared goal.”

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How Sentinel-6B Measures Earth’s Changing Oceans

Sentinel-6B uses radar altimetry, which works by measuring the time it takes for radar pulses to travel from the satellite to the ocean surface and back again. Combined with extremely precise satellite positioning, this data reveals:

• Sea-surface height

• Significant wave height

• Wind speed

These measurements are vital not just for climate monitoring, but also for real-time ocean forecasting and maritime safety.

The satellite also carries an advanced microwave radiometer, developed by NASA. This instrument corrects for water vapour in the atmosphere, ensuring the accuracy of sea-level measurements.

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What Happens Next

Sentinel-6B is currently in the Launch and Early Orbit Phase (LEOP) under ESA’s mission control in Germany. After all systems are verified and stabilised, control of the satellite will be handed over to Eumetsat, which will manage its routine operations.

Its data will contribute directly to global climate models, coastal planning, and long-term assessments of ocean health — helping scientists and policymakers better understand and manage the impacts of climate change.