GMES (Global Monitoring for Environment and Security) is the response to the need by Europe for geo-spatial information services. It provides autonomous and independent access to information for policy-makers, particularly in relation to environment and security. ESA, as main partner to the European Union in GMES, is working on multi-mission facilities and ground segment operations and is preparing the Space Component for GMES with a series of studies and preparatory activities for the development of a series of satellites missions (the Sentinels) and the integration of national and European missions to guarantee continuity of data and services.