Speaker
Description
Keywords: Catastrophic Disruption, Kinetic Impactor, Laboratory Experiments, Numerical Simulations
NASA’s DART mission successfully altered the orbit of a 160-m-diameter asteroid, demonstrating kinetic impactor technology for Planetary Defense. While successful, the DART mission also raised new questions about the extent at which kinetic impactors could be used in real scenarios. In particular, kinetic impacts on 50- 100 m-diameter NEAs could lead to a disruption event, rather than a deflection. In such an event, it is not yet clear that the threat would be adequately mitigated, or if the threat would be exacerbated by multiplying the number of potential Earth-bound impactors. Recent research into this problem has used crude approximations for the disruption limits of asteroids in this size range to argue against the use of kinetic impactors, favoring alternative mitigation techniques. Here, we study the outcomes of impacts in the catastrophic disruption regime of small coherent asteroids to better understand the limits at which kinetic impactors could be used for asteroid mitigation.
The goals of this work are to:
1. Conduct hypervelocity impact experiments and simulations on to asteroid simulant to better understand the disruption threshold of coherent NEAs.
2. Conduct numerical simulations of disruption dynamics to evaluate the extent to which catastrophic disruption mitigates or exacerbates the asteroid threat.
To achieve the first goal, we are conducting hypervelocity impact experiments using the HyFire lab at the Hopkins Extreme Materials Institute. This includes a two-stage gas gun and a suite of diagnostic tools which include highspeed cameras capable of capturing the post-impact dynamics of fragments as a target is disrupted. We will be using asteroid analogs in our experiments as these would be the best analogs to NEAs. The experiments inform larger-scale simulations of disruptive impacts on to 50-100 m-diameter targets by a kinetic impactor.
To achieve the second goal, we use the results of our experiments and simulations to setup computational simulations of the dynamics of impact fragments following a kinetic impact, using the N-body code pkdgrav. For this work, we will simulate the disruption of hypothetical 2024 PDC25 for cases of its most likely size range (90 - 160 m). Using our high-fidelity disruption modeling, we will present an assessment of the consequence of the disruption of 2024 PDC25 at different points in time before its potential impact date of April 24, 2041.