Overall Results of the SMPAG Work Package on Mission Scenarios in Response to the 2025 Planetary Defense Conference Hypothetical Asteroid Impact Threat Scenario

The members of the Space Mission Planning Advisory Group have performed an asteroid impact simulation exercise over a medium size asteroid with impact chances on 24 April 2041, in preparation for the 2025 Planetary Defense Conference. The exercise articulated on two different simulation periods lasting respectively two months and a half and four months. In the first period, Epoch 1, the asteroid impact probability grew from 1.6% to 10% and was played in real time. A preliminary assessment of the required actions that would need to be implemented and a set of recommendations were provided at a plenary SMPAG session held on 10 October 2024. Epoch 2 was simulated after the fast flyby of a reconnaissance mission by the asteroid in April 2028 that allowed refining the asteroid size, and impact location. An assessment of the decisions that were required and the feasible mission options was performed in order to facilitate a recommendation making by the SMPAG plenary. Mission options included kinetic impactors, ion-beam deflection and nuclear explosive devices.