On December 23, 2021, Copernicus Sentinel-1B encountered an anomaly related to the instrument electronics power supply provided by the satellite platform, preventing it from providing radar data. Since then, spacecraft operators and engineers have worked tirelessly to resolve the issue. Unfortunately, despite all concerted efforts, ESA and the European Commission announce the end of the Sentinel-1B mission. Copernicus Sentinel-1A remains fully operational and plans are in effect to launch Sentinel-1C as soon as possible.
ESA’s Director of Earth Observation Programs Simonetta Cheli said: “Unfortunately, we have to announce the end of the Copernicus Sentinel-1B satellite mission. The conclusion reached by the Anomaly Review Board is that it is impossible to recover the 28V regulated bus from the satellite’s C-band synthetic aperture radar antenna feed unit, which is needed to power the radar electronics.
“Sentinel-1A remains in very good health in orbit, continuing to provide high quality radar imagery for a multitude of applications. Our goal is to accelerate the launch of Sentinel-1C. Now, thanks to the successful maiden flight of the Vega-C rocket on July 13, we are aiming with Arianespace for launch in the second quarter of 2023.”
The European Commission’s Acting Director for Space (Directorate General for Defense Industry and Space), Paraskevi Papantoniou, said: “The permanent unavailability of the Sentinel-1B satellite represents a significant loss for the European Union’s space program and the European Commission is committed to mitigating its impact. . In particular, we succeeded in bringing forward the launch of the Sentinel-1C satellite.
“In the meantime, data from contributing Copernicus missions, including that of European New Space companies, will continue to be used to support the most critical Copernicus Services products that are affected. The preparations for the de-orbiting of the Sentinel-1B satellite are an example of our joint commitment, for the European Union and ESA, to a clean and responsible space, using the surveillance and monitoring capabilities of the EU space.
In April 2014, Sentinel-1A was the first satellite launched for Copernicus, the Earth observation component of the European Union’s space program. While the European Union is in charge of Copernicus, ESA develops, builds and launches dedicated Sentinel satellites. It also operates some of the missions.
After the launch of Sentinel-1B in April 2016, with the mission consisting of two identical satellites in 180° orbit, the mission was able to image the planet with a maximum repeat rate of six days, down to daily coverage at high latitudes.
Featuring advanced radar technology to provide an all-weather, day and night source of Earth’s surface imagery, the ambitious Sentinel-1 mission has raised the bar for space-based radar.
The mission benefits from many Copernicus services and applications, such as those related to Arctic sea ice monitoring, iceberg tracking, routine sea ice mapping, glacier velocity monitoring, monitoring of the marine environment, including oil spill monitoring and ship detection for maritime purposes. security as well as the monitoring of illegal fishing. It is also used for monitoring ground deformation resulting from subsidence, earthquakes and volcanic eruptions, mapping for forest, water and soil management, and mapping to support humanitarian relief. and crisis situations.
With such an important role to play and users relying on timely data, ESA acted as soon as it was clear that the Sentinel-1B power issue could take a few weeks to resolve, which was the hope at the end of December.
ESA Sentinel-1 mission manager Pierre Potin said: “Together with the European Commission, we are working to fill some of the data gaps by adjusting the Sentinel-1A observation plan and radar data from other satellite missions contributing to Copernicus. program. For example, we are able to use data from the Canadian Radarsat-2 and Radarsat Constellation mission, the German TerraSAR-X, the Italian COSMO-SkyMed and the Spanish PAZ to support operational surveillance of sea ice for the Copernicus marine environment monitoring service.
“As we continue to try to minimize user inconvenience and get Sentinel-1C into orbit as soon as possible, we are also preparing for the responsible disposal of Sentinel-1B.”
Sentinel-1 spacecraft operations manager Alistair O’Connell added: “We have Sentinel-1B under control, all other systems except the power affected unit, which prevent radar activation, continue to operate nominally, and we are conducting regular spacecraft health monitoring and routine orbit control maneuvers. We will keep Sentinel-1B under control until that we can begin the elimination process, which we will begin once Sentinel-1C is safely in orbit.
“The deorbiting of Sentinel-1B will be carried out in accordance with the space debris mitigation requirements that were in place for ESA projects at the time of the design of Sentinel-1A and Sentinel-1B, which means that re-entry into the atmosphere will take place within 25 years.. In practice, the duration of re-entry should be much shorter.
Copernicus Sentinel-1C presents a world first new separation mechanism that will help avoid space debris.
A summary of the description of the anomaly, investigations and recovery attempts, as well as parallel Sentinel-1 mission-level actions and the way forward can be found on the Sentinel Online website.