With the successful launch of Sentinel-1A, in April 2014, a new age in Earth Observation (EO) is becoming a reality. The sentinel Series, together with the Earth Explorers, the continuity of well-established meteorological missions and the national missions, will provide an unprecedented observation capacity to support the scientific community to address the key challenges in Earth system science and the priorities of the major international scientific organisations and programmes. The Sentinel missions are driven by operational services and their particular requirements. However, as widely recognised, operational missions also bear a wealth of information for scientific exploration in different scientific disciplines. This is in particular true considering the high temporal revisit provided by the planned constellations of satellites, the novel instrumentation covering different spatial and spectral scales and the long-term commitment. Data access for scientific use is currently being favoured in the Copernicus data access principles. Considering the above, this study was an ESA contribution to explore the potential of sentinel missions for scientific purposes and to prepare for their scientific exploitation. The improved observational capacities of the Sentinel missions have been analysed and their potential to contribute to achieve the major challenges in Earth science have been explored. To this end, the project supported though a number of workshop and conferences the development of a scientific roadmap identifying major scientific requirements in terms of new products and novel retrieval methods that may contribute to advance science in the coming years. Requirements of the science community were analysed beyond the product portfolios of the Copernicus operational services and a number of priority areas for further development and research have been identified.