Global Monitoring for Environment and Security (GMES) is the most ambitious operational Earth Observation programme to date and will provide global, timely and easily accessible information in application domains such as land, marine, atmosphere, emergency response, climate change and security. To accomplish this, the European Union (EU)-led GMES programme comprises three components namely the space component, the in-situ component and the service component. The space component, led by ESA, is in its pre-operational stage, serving users with satellite data acquired by the so called "GMES Contributing Missions" already available today or planned at European, national and international level. It will become operational once the dedicated space infrastructure, comprised by the "Sentinel" missions and their corresponding ground segments are operational. The first of these satellite series will be launched in 2013. The Sentinel missions will provide a unique set of observations utilising different techniques spanning C-band SAR, mid to medium resolution optical and thermal observations with increased spectral resolution, altimeter and dedicated spectrometers for atmospheric chemistry. This data, combined with in-situ data, some assimilated into models, will then be turned into services for monitoring the environment, the climate and for security related issues. The GMES Space Component (GSC) is organised in two overlapping phases: the development phase and the operational phase, the latter planned to start in 2014. The main challenge is now to ensure the programme's long-term sustainability. (C) 2012 Elsevier Inc. All rights reserved.
