This is the start of a launch campaign that will lead up to the launch date, still to be announced. The satellite will reach its orbit on board an Ariane 6.

Meanwhile, the Sentinel-1 mission will continue to deliver a supply of radar images of Earth’s surface, performing in all weathers, day-and-night. It 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 Sentinel-1 mission has contributed data to scientific studies on a wide range of topics, including these recent examples:

• An analysis of flooding beneath the Greenland ice sheet
• Destructive fires in South America’s endangered forests
• Ground movement following a powerful earthquake
• Measuring one of the biggest ever methane releases related to human activity

Sentinel-1D will continue this work and will now undergo a series of launch preparation activities to ensure it is ready for liftoff.

Ramón Torres, Sentinel-1 Satellite Mission Director at ESA, commented, “This time we are launching the fourth Sentinel-1 satellite, and last of the first generation, on an Ariane 6, which will be an important moment for the whole of our space community. To see this mission, the first of the Copernicus programme family and a cornerstone of the Earth observation component of Europe’s space programme, be lifted into orbit on Europe’s newest heavy lift rocket, feels quite momentous. I would like to thank and congratulate all Sentinel-1 team members and our partners who have worked so diligently to make this milestone a huge success.”

Simonetta Cheli, Director of Earth Observation Programmes at ESA, added, “It is really a credit to the strong partnership between ESA and the European Commission that we are now preparing to launch another satellite for the Copernicus programme. Sentinel-1 has provided vital radar data that has been used in emergency responses, in scientific studies and in climate observation – a range of use-cases that highlights just how invaluable Copernicus is to our society.”

The Copernicus Sentinel-1 mission is based on a constellation of two identical satellites flying in the same orbit but 180° apart, to optimise global coverage and data delivery for Copernicus.

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.

Sentinel-1D will launch later this year.

Radar vision for Copernicus

 

How do radar satellites work?
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Sentinel-1D has a C-band synthetic aperture radar (SAR) instrument on board, which allows it to capture high-resolution imagery of Earth's surface. This powerful radar system operates in several modes, including wide swath and high-resolution, providing detailed data on land subsidence, ice movements and ocean conditions.

And like the Sentinel-1C satellite that was launched last year, Sentinel-1D will also carry an Automatic Identification System (AIS), which is a new instrument designed to augment the SAR payload data for maritime ship traffic monitoring applications.

Quelle: ESA

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Update: 9.10.2025

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Sentinel-1D preparations underway in Kourou

1. Better revisit time and coverage: With two satellites in the same orbit 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 have a C-band Synthetic Aperture Radar (SAR) instrument on board, which allows it to capture high-resolution imagery of Earth’s surface. They are also equipped with an Automatic Identification System (AIS) instrument 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.
4. GNSS compatibility: There are other improved onboard capabilities for Sentinel-1. For example, while Sentinel-1A and -1B were compatible only with the Global Positioning System (GPS), Sentinel-1C and -1D are compatible with the whole Global Navigation Satellite System (GNSS), including Galileo.

Testing confirms Sentinel-1D is ready

Functional checks have been performed on the spacecraft to confirm the spacecraft is in working order after being transported to Kourou.

These tests started with a pressurisation and leak check before the spacecraft was switched on. Afterwards several tests were performed to assess the spacecraft's health status and the correct functionality of all sub-systems. The AIS antenna assemblies, which were transported to the launch site in separate containers, have also been integrated onto the spacecraft and the final connectivity test to ensure their correct electrical connection concluded the spacecraft functional testing.

The spacecraft is now ready for the next steps, including spacecraft finalisation before fuelling.