Copernicus Sentinel-1

Sentinel-1 is a satellite constellation conducted by the European Space Agency, originally consisting of Sentinel-1A and Sentinel-1B, with two more satellites, Sentinel-1C and Sentinel-1D, in development. Sentinel-1A launched in 2014 and Sentinel-1B launched in 2016, with Sentinel-1C planned for launch in 2024. The satellites have a Sun-synchronous orbit and carry a C-band synthetic-aperture radar instrument, providing data that is freely accessible for public, scientific, or commercial use. The data is used for a wide range of applications, including marine and land monitoring, emergency response, and economic applications, such as measuring land subsidence and soil moisture.learn more on wikipedia