The European Space Agency (ESA) has announced that free and open access to Sentinel satellite data will become available during the Copernicus operational phase. Copernicus is an earth observation program operated by a partnership of the European Commission (EC), European Space Agency (ESA), and the European Environment Agency (EEA). The European Delegated Act on Copernicus data and information policy provides for free, full and open access to users of environmental data from the Copernicus program which will include data gathered from the Sentinel satellites.
The Sentinel missions are a group of five satellites, the first of which is slated for launch in the spring of 2014. According to the ESA: All-weather, day and night radar images from Sentinel-1 to be used for land and ocean services. Sentinel-2 will deliver high-resolution optical images for land services and Sentinel-3 will provide data for services relevant to the ocean and land. Sentinel-4 and Sentinel-5 will provide data for atmospheric composition monitoring from geostationary and polar orbits, respectively. All Sentinel satellites are planned for launch in 2014 and 2015.
Until data from the Sentinel missions is available, the GMES Data Access Portfolio has a list of datasets users can browse through. Data can be viewed by a variety of categories such as service, mission group (type of imaging and monitoring), mission, and instrument.