The Sentinels are a fleet of European Space Agency (ESA) satellites designed to acquire measurements from multiple sensor types that will provide information necessary to meet Europe’s Copernicus program objectives.
The first mission in the series, the Sentinel-1 constellation, includes twin satellites that each carry C-band synthetic aperture radar (SAR) which together provide all-weather, day-and-night imagery of Earth’s surface.
Sentinel-1A was launched on 3 April 2014, and Sentinel-1B on 25 April 2016. They orbit 180° apart, together imaging the Earth every six days.
In December 2021, an anomaly in the power supply of Sentinel-1B caused the SAR sensor to stop working. Attempts to restore power to the sensor failed, and the mission officially ended on August 3, 2022.
The loss of one of the Sentinel-1 satellites means that the frequency of observations and global coverage will be significantly reduced until the launch and commissioning of Sentinel-1C. This is predicted to be completed in the third quarter of 2023. Sentinel-1B will be deorbited at this time.
The Sentinel-1 constellation benefits numerous services, such as monitoring of Arctic sea-ice extent, routine sea-ice mapping, and surveillance of the marine environment. Applications include oil-spill monitoring and ship detection for maritime security; monitoring land-surface for motion risks; mapping for forest, water, and soil management; and mapping to support humanitarian aid and crisis situations.
Updated August 22, 2022
International Collaboration
Sentinel-1 is the result of close collaboration among ESA, the European Commission, industry, service providers, and data users.
NASA’s provision of the complete ESA Sentinel-1 SAR data archive through the ASF DAAC is by agreement between the U.S. State Department and the European Commission (EC). As part of the Earth-observation Copernicus program, the Sentinel mission will provide scientists with accurate, timely, and easily accessible information to help shape the future of our planet.
Content on ASF’s Sentinel web pages is adapted from ESA’s Sentinel website.
