Speaker
Description
In an idealized mitigation scenario, one would strive for threat interception to occur as far away–in both space and time–from Earth as possible. However, reality may make such a desirable outcome improbable to impossible, due to hurdles like uncertainty in the threat's characteristics or lack of time for preparation. In a scenario where extended warning time and preparation are out of reach, it is imperative to consider terminal mitigation methods. We analyze the effectiveness of mitigation via intentional robust disruption (IRD) for objects similar to 2024 PDC25, the 90-160 m diameter threat described in the 2025 Planetary Defense Conference (PDC) Hypothetical Asteroid Impact Scenario.
Pulverize It (PI) is a planetary defense concept which is designed to operate in both short-warning and extended time scale interdiction modes, representing a unique multi-modal approach to asteroid threat mitigation. PI is under development as part of a NASA Innovative Advanced Concepts (NIAC) Phase II study. The method utilizes high-density hypervelocity impactors to penetrate and fragment an incoming asteroid. In extended warning scenarios in which the asteroid is intercepted far from Earth, PI can be used for either robust disruption via complete fragmentation or enhanced deflection via partial fragmentation. In short-warning scenarios, PI can be used in a terminal mode to disrupt an incoming asteroid into small fragments (<10 m diameter) which then intercept Earth, resulting in a series of high-altitude airburst events with spatial and temporal spread. This yields ground-level optical pulses and de-correlated shock waves which distribute the energy of the parent asteroid.
PI represents the first planetary defense method with multi-modal capability and with the ability to respond to rapid, short-warning threats. We compare PI to kinetic impact (deflection) by simulating mitigation of a Dimorphos-scale (160 m diameter) asteroid model to compare with NASA's Double Asteroid Redirection Test (DART) mission. We find that, in general, PI requires a lower launch mass than kinetic impact missions for the same threat, which enables a fully capable planetary defense system that relies solely on pre-existing launch vehicles. Our simulations support the proposition that PI is an effective multi-modal approach for planetary defense, particularly for objects within the diameter range of 2024 PDC25, even in terminal interdiction modes which yield ground effects that are vastly less damaging in comparison to unmitigated cases.