"Space missions in Earth orbit have demonstrated that men can survive and work in space for long durations. However, there are pending technological, medical and psychological issues to be solved before adventuring in longer duration space missions. Furthermore technological breakthroughs, e.g. in life support systems and recycling technologies are required to reduce the costs of these expeditions. Solving these issues will need scientific and technological breakthroughs of interest for clinical and industrial applications and also allow identifying the relevance of these questions to health issues on Earth. Despite existing ESA or NASA studies or roadmaps Europe still has no scientific and industrial roadmap. The THESEUS objective is to develop an integrated life sciences research roadmap enabling European human space exploration in synergy with ESA, taking advantage of the European expertise and identifying the potential of non space applications and dual research and development. It will (1) identify disciplinary research priorities; (2) focus on fields with high terrestrial application potential; (3) build a European network as the core of this strategy. This will be achieved by setting-up and coordinating 15 Expert Groups of European and international experts, ensuring that complementary expertises are gathered and that experts coming from non European countries and from the industrial sectors are included. They will be asked to develop their activities and recommendations based on the scenario proposed by ESA Space Exploration Architecture (human presence in Low Earth Orbit, return to the Moon and human exploration of Mars). The work plan is structured to develop a survey of the state of the art, an improved focus on the relevance of the relevant research for current and upcoming health challenges on Earth and otential bio-medical application, a detailed set of disciplinary priorities and an integrated roadmap providing strategic orientations for research."