Collisions of asteroids and comets with the Earth have taken place frequently over geological history and have altered the evolutionary course of life; there is no reason why they should not continue to hit the Earth at irregular and unpredictable intervals in the future. Thousands of near-Earth objects (NEOs), mainly asteroids, have been discovered over the past 20 years and the reality of the impact hazard has been laid bare. Can we protect our civilization from the next major impact?We propose to carry out a detailed analysis of the open questions relating to realistic options for preventing the collision of a NEO with the Earth. Solutions will be provided to critical scientific and technical issues that currently stand in the way of demonstrating the feasibility of promising mitigation options via test missions. While a mitigation test mission is beyond the financial scope of the present Call, we aim to provide detailed test-mission designs for the most feasible mitigation concepts, facilitating the rapid development of actual test missions at a later stage.Our project concept includes laboratory experiments and associated modelling to provide the necessary data pertaining to the behaviour of a NEO during a deflection attempt. The experimental results and modelling will help to improve our understanding of the nature of NEOs and allow the feasibility of mitigation techniques and mission designs to be accurately assessed.Our project includes appropriate partners from established space-faring nations outside the European Union. We propose to formulate a global response campaign roadmap that may be implemented when a serious impact threat arises. The roadmap will consider the necessary international decision-making milestones, required reconnaissance observations, both from the ground and from rendezvous spacecraft, practical prerequisites, such as precise orbit tracking, and a campaign of perhaps several mitigation missions, depending on circumstances.