"The strategic importance of space systems is growing in Europe, for civil and defence applications (satellite communications, ..). Recent examples have shown that on-orbit collisions brought on by space debris are important threats. On one hand, some space debris are routinely tracked, making the collisions predictable, but they increase the cost of space missions’ management. On the other hand, most debris are untracked because they are too small, making prediction impossible. The way to reduce vulnerability is then to reduce severity of collision and probability of occurrence. The proposed P²-ROTECT project aims to assess the risks associated with collisions and recommend possible solutions such as better prediction, protection or action on debris environment to reduce vulnerability of missions. But it is mandatory to elaborate a vulnerability index which quantifies the efficiency of solutions with respect to trackable and untrackable debris effects and provides access to sensitive terms of collision probability or severity. Furthermore, trade-offs are made between efficiency and cost to propose new design options for space infrastructures. In order to work with concrete examples depending on orbit types, three missions of interest for EU are analysed: Sentinel-I in Low Earth Orbit, GALILEO constellation in Medium Earth Orbit and MTG, the weather observation constellation in Geostationary Orbit. The Consortium includes well-known partners capable of analysing space missions at all levels (S/C component, mission) and able to provide innovative solutions for risk reduction.The P²-ROTECT objective and methodology match with the objectives of Activity “Security of space assets from on-orbit collisions”. Concerning the complementarities with the ESA SSA proposal, the propositions are clearly oriented towards low-cost solutions to contribute to space surveillance and improvement of collision prediction methods, while raising situational awareness on a European level"