ESA developed a series of next-generation Earth observation missions, on behalf of the joint ESA/European Commission initiative Copernicus.
The goal of the Sentinel programme is to replace the older Earth observation missions which have retired, such as the ERS and Envisat missions, or are currently nearing the end of their operational life span. This will ensure a continuity of data so that there are no gaps in ongoing studies.
Each mission focuses on a different aspect of Earth observation; Atmospheric, Oceanic, and Land monitoring, and the data is of use in many applications.
For mission planning information, see the Copernicus Mission pages.