The Space Mission Planning Advisory Group SMPAG's mission is to prepare for an international response to a Near Earth Object impact threat through the exchange of information, development of options for collaborative research and mission opportunities, and to conduct Near Earth Object (NEO) impact threat mitigation planning activities. This paper presents the preliminary work performed by the Italian Space Agency Delegation for defining few reference missions for different NEO-threat scenarios and carrying out Phase 0 studies. In this paper two scenarios are identified to study the possible response in case of a real NEO-threat. A direct and resonant impact scenario for an asteroid deflection mission are identified resembling to the asteroid 2010RF12 but with an increased asteroid mass. Then the mission analysis and spacecraft design for the direct impact case is performed and the results discussed
