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Asteroid Disruption and Deflection Simulations for Multi-Modal Planetary Defense
Authors:
Alexander N. Cohen,
Philip Lubin,
Darrel Robertson,
Mark Boslough,
Sasha Egan,
Brin Bailey,
Angela M. Stickle,
Elizabeth A. Silber,
Peter Meinhold,
Dharv Patel
Abstract:
Planetary defense from asteroids via deflective means alone does not offer viable solutions in terminal scenarios where there is little warning time before impact. The PI method of planetary defense enables operation in terminal interdiction modes where there is little warning time prior to impact, but can also operate in the same extended time scale interdiction modes as made possible by traditio…
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Planetary defense from asteroids via deflective means alone does not offer viable solutions in terminal scenarios where there is little warning time before impact. The PI method of planetary defense enables operation in terminal interdiction modes where there is little warning time prior to impact, but can also operate in the same extended time scale interdiction modes as made possible by traditional deflection techniques, which results in a versatile, multi-modal planetary defense capability. The method is also practical and cost-effective since it relies solely on launch vehicles and penetrator materials already available today, and thus presents itself as a logical and competitive option for planetary defense. As per the PI method, we investigate the effectiveness of rubble pile asteroid disruption and deflection via hypervelocity impacts with 10:1 aspect ratio cylindrical tungsten penetrators. We present the results of an ongoing simulation campaign dedicated to investigating the PI method, using the Lawrence Livermore National Laboratory (LLNL) arbitrary Lagrangian-Eulerian (ALE) hydrodynamics code ALE3D run with the High-End Computing Capability (HECC) at NASA Ames Research Center. We model heterogeneous rubble pile asteroids with a distribution of spherical boulders of varying initial yield strengths set within a weak binder material. We find that rubble pile asteroids of this type in the 20 - 100 meter-class can be effectively mitigated via 20 km/s impacts with 100 - 1000 kg penetrators via the coupling of the penetrator kinetic energy into the bulk material of the asteroid.
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Submitted 6 August, 2026;
originally announced August 2026.
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Observational Evidence for Wind-Driven Low-Pass Filtering of Infrasound at Short Range
Authors:
Elizabeth A. Silber,
Daniel C. Bowman,
Sasha Egan,
Lawrence Burkett,
Michael Fleigle,
Keehoon Kim,
Tesla Newton,
Loring P. Schaible,
Richard Sonnenfeld,
Nora Wynn,
Jonathan Snively
Abstract:
Infrasound from controlled explosions provide a unique opportunity to isolate atmospheric effects on propagation. We report observations from two campaigns in May and October 2024, each featuring 10-ton TNT-equivalent controlled surface chemical explosions recorded by a dense network of 31 single-sensor stations within 23 km. Despite identical sources, the observed wavefields were very different.…
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Infrasound from controlled explosions provide a unique opportunity to isolate atmospheric effects on propagation. We report observations from two campaigns in May and October 2024, each featuring 10-ton TNT-equivalent controlled surface chemical explosions recorded by a dense network of 31 single-sensor stations within 23 km. Despite identical sources, the observed wavefields were very different. October signals followed a near-unimodal period-distance trend, whereas May signals exhibited a pronounced azimuthal bifurcation in both period and celerity. Downwind paths largely preserved the short-period baseline observed in October, while upwind paths showed systematically longer periods caused by wind-driven low-pass filtering. This study provides the first direct observational evidence that tropospheric winds can impose azimuth-dependent low-pass filtering at local ranges, without the influence of measured temperature inversions. Thus, the structure of the atmosphere can modify the spectral characteristics of low-frequency acoustic waves even at a distance of only a few kilometers.
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Submitted 30 January, 2026;
originally announced February 2026.
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Multi-parameter constraints on empirical infrasound period-yield relations for bolides and implications for planetary defense
Authors:
Elizabeth A. Silber,
Josep M. Trigo-Rodríguez,
Iyare Oseghae,
Eloy Peña Asensio,
Mark Boslough,
Rodney Whitaker,
Christoph Pilger,
Philip Lubin,
Vedant Sawal,
Claus Hetzer,
Randy Longenbaugh,
Peter Jenniskens,
Brin Bailey,
Esther Mas Sanz,
Patrick Hupe,
Alexander N. Cohen,
Thom R. Edwards,
Sasha Egan,
Reynold E. Silber,
Summer Czarnowski,
Miro Ronac Giannone
Abstract:
How effective are methods for estimating bolide energies from infrasound signal period-yield relationships? A single global period-energy relation can obscure significant variability introduced by parameters such as the atmospheric Doppler wind profile and the bolide's energy deposition profile as a function of altitude. Bolide speed, entry angle, burst altitude, and multi-episode fragmentation al…
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How effective are methods for estimating bolide energies from infrasound signal period-yield relationships? A single global period-energy relation can obscure significant variability introduced by parameters such as the atmospheric Doppler wind profile and the bolide's energy deposition profile as a function of altitude. Bolide speed, entry angle, burst altitude, and multi-episode fragmentation all may play a role in defining the detected period of the shockwave. By leveraging bolide light curve data from the Center for Near Earth Object Studies (CNEOS), we re-examined the period-energy relation as a function of these parameters. Through a bootstrap approach, we show that various event subsets can deviate from widely cited period-energy models and we identify which specific conditions most strongly reshape the period-energy scaling. The results define both the fidelity and reliability of period-energy relations when no additional data beyond the infrasound record is available and improve the outcome when supporting data from bolide trajectories and light curves are included. Ultimately, these findings expand the scope of earlier models, providing a nuanced and robust framework for infrasound-only yield estimation under a range of bolide scenarios.
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Submitted 5 May, 2025;
originally announced May 2025.