Monday, 8th of September
After the successful launch and commissioning of Sentinel‑1C, the Sentinel-1 team have now returned to Kourou to begin launch preparations for Sentinel‑1D.
Sentinel‑1C was launched on 5th December 2024 on Vega-C Return to Flight.
Sentinel‑1D is set to join its sibling in orbit, and together they will significantly enhance the capabilities of the Copernicus Earth observation programme.
Sentinel‑1D is scheduled to launch later this year onboard an Ariane 6.
The Launch campaign early team arrived in Kourou on 8th September 2025. The work started the day after at 08:30 sharp, with daily meetings and preparations to receive the spacecraft. A few days earlier, our fantastic IT team had arrived to set up the network and offices.
Introducing Sentinel‑1D & how it complements -1C
Sentinel-1A was the first satellite in the series, launched in April 2014, followed by the launch of Sentinel-1B in 2016. The Sentinel-1B mission came to an end in August 2022 after experiencing a technical fault that rendered it unable to acquire data. The satellite has been successfully de-orbited and will re-enter Earth’s atmosphere within 25 years. Sentinel-1C was launched in December 2024 to take over the role of Sentinel-1B.
With Sentinel‑1C now operational, the full constellation mission (with Sentinel-1A) continues to deliver a supply of radar images of Earth’s surface, performing in all weathers, day-and-night. The mission makes a key contribution to Europe’s Copernicus programme by supporting a broad range of applications that help manage our environment, understand and tackle the effects of climate change and safeguard everyday lives.
The launch of Copernicus Sentinel-1D will provide a much-needed replacement to Sentinel-1A, which has been in orbit for 11 years now, well beyond its planned lifetime.
Sentinel-1C and Sentinel-1D have a C-band Synthetic Aperture Radar (SAR) instrument on board, which allows it to capture high-resolution imagery of Earth’s surface, and an Automatic Identification System (AIS), which is a new instrument designed to augment the SAR payload data for maritime ship traffic monitoring applications. They also bring other improvements to the Sentinel-1 mission, such as compatibility with Galileo Global Navigation Satellite System (GNSS) and improved onboard capabilities.
How Sentinel‑1C & -1D working together improves the mission
Putting both Sentinel-1C and -1D into service together achieves several gains:
1. Better revisit time / coverage
With two satellites flying in the same orbit but phased 180° apart, the revisit rate over any location on Earth improves. This means more frequent imaging, faster change detection, better monitoring.
2. Enhanced features working in synergy
Both satellites are equipped with AIS antennas to improve detection and tracking of ships. When both are operational, more frequent AIS observations are possible.
3. Streamlined operations and cost savings
Because Sentinel-1C has just gone through commissioning, lessons learned can be applied to Sentinel-1D, reducing time and risk.
What we’re doing now at Kourou for Sentinel‑1D
Launch preparation, including final checks and tests of the satellite after transportation, followed by fuelling of Sentinel-1D and final integration with Ariane 6, to be ready for Launch.
Why this matters
Together, Sentinel‑1C and Sentinel‑1D ensure that Europe’s Copernicus mission continues to deliver timely, reliable Earth observation data. For users who depend on frequent updates, disaster response teams, environmental agencies, maritime authorities, climate scientists the difference between one vs. two satellites can be the difference between late warning and critical early warning.
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