Momentum transfer coefficient constraints for the 2024 PDC25 Hypothetical Asteroid Impact Scenario

Abstract: In Epoch 2 of the 2024 PDC25 Hypothetical Asteroid Impact Scenario, an asteroid is confirmed to be on a collision course with the Earth, and its size and surface composition have been well characterized via a flyby mission. A kinetic impactor deflection strategy is the most technologically mature path in order to mitigate this threat. Our goal is to constrain the possible range in momentum transfer coefficients, with implications for the number of impactors and the disruption risk. We conduct a series of numerical simulations, using a shock physics smoothed particle hydrodynamics code, in which we vary the impact velocity, cohesive properties and physical properties (mass / porosity) of the target asteroid. Given a judiciously chosen impactor mass, we show that the momentum transfer coefficient range is capable of a moderate-to-large enhancement of the asteroid deflection, yet keeps the disruption risk firmly at bay. These results are generally unique in having higher impact velocities compared to most previous studies.