The Copernicus Sentinel-1D satellite, launched last November, is now fully operational after successfully completing its critical in-orbit commissioning phase. With all four Sentinel-1 satellites now deployed, this achievement marks a major milestone for this flagship radar mission — a journey that began more than a decade ago and has helped pave the way for the future of Earth observation.
When Sentinel-1A, the first of this generation, launched in 2014, it marked more than the start of a single mission; it signalled the beginning of Copernicus, the Earth observation component of the European Union’s space programme. Its success demonstrated that Europe could deliver consistent, high-quality Earth observation data for the Copernicus Services and beyond.
The Sentinel-1 mission was designed as a constellation of two identical satellites orbiting Earth 180 degrees apart for optimal coverage. In 2016, Sentinel-1B was launched to pair with Sentinel-1A. The Sentinel-1B mission came to an end in August 2022 after experiencing a technical anomaly that rendered it unable to acquire data. However, Sentinel-1C was launched in 2024 to restore the constellation, followed by Sentinel-1D one year later.
The mission delivers high-resolution synthetic aperture radar (SAR) images of Earth’s surface in all weather conditions, day and night. The data are critical for monitoring everything from natural disasters and sea ice to land deformation and deforestation. The constellation’s all-weather, day-and-night imaging has become indispensable for scientists, policymakers, and emergency responders worldwide.
Perhaps most remarkable is the longevity of the data record — the satellite series is on track to provide an unprecedented two decades of continuous radar observations. This long-term dataset strengthens Europe’s leadership in tracking climate change and environmental shifts, offering a reliable foundation for decision-making and research in an increasingly uncertain world.
The Sentinel-1 mission has also broken ground in another crucial area: sustainability in space. Sentinel-1C and Sentinel-1D carry a world premiere of a new separation mechanism designed to help avoid space debris, underscoring the European Space Agency’s and the European Commission’s commitment to clean space principles.
With the last of the first-generation Sentinel-1 satellites now beginning its operational life in orbit, ESA and the European Commission are looking ahead.
Nuno Miranda, ESA’s Sentinel-1 Mission Manager, stated:
“Sentinel-1 began as a trailblazer. With the successful commissioning of Sentinel-1D, it now stands as a cornerstone — reflecting Europe’s achievements while serving as a launchpad for what comes next. For several years, we have been advancing a follow-on mission: Sentinel-1 Next Generation, designed to ensure continuity of measurements well into the mid-2030s and beyond. These future satellites are expected to deliver enhanced performance and new capabilities, building on the legacy of their predecessors while addressing emerging scientific and societal needs.”
