Options and uncertainties in planetary defense: Impulse-dependent response and the physical properties of asteroids
| Autor: | Kirsten Howley, Galen Gisler, Joshua R. Lyzhoft, Ronald Y. Leung, Kevin Greenaugh, Paul L. Miller, Melak Zebenay, Joseph A. Nuth, Bernard D. Seery, Robert P. Weaver, Joseph Wasem, Catherine S. Plesko, David S. P. Dearborn, Brent W. Barbee, Megan Bruck Syal |
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| Rok vydání: | 2020 |
| Předmět: |
020301 aerospace & aeronautics
Composition dependence business.industry Aerospace Engineering 02 engineering and technology Impulse (physics) Kinetic energy 01 natural sciences 0203 mechanical engineering Impact crater Asteroid 0103 physical sciences Environmental science Black-body radiation Aerospace engineering Material properties business Ejecta 010303 astronomy & astrophysics |
| Zdroj: | Acta Astronautica. 166:290-305 |
| ISSN: | 0094-5765 |
| DOI: | 10.1016/j.actaastro.2019.10.026 |
| Popis: | Though rare, asteroid impacts are inevitable, and with the current state of technology, kinetic impactors are the preferred but not the complete solution. If the time to impact is short, or the threatening body too large, nuclear deflection serves as a final option. This work is part of an integrated study by National Aeronautics and Space Administration (NASA) and the National Nuclear Security Administration (NNSA) to better determine the relative efficacy of these complimentary approaches. In particular, we examine the important material properties that affect each approach, to improve critical characterization efforts, and reduce uncertainty in the limits of the impactor technology. Impact speeds for kinetic impactors on Near-Earth Object (NEO) intercept trajectories commonly range from 5 to 20 km/s, resulting in significant crater ejecta and a momentum enhancement above that carried by the impactor. This enhancement depends substantially on the strength and porosity of the asteroid, as well as the impact speed. Here simulations from different codes are presented, along with constraints from experimental measurements. The uncertainties due to ignorance of the strength and porosity of the impact point are significant in determining the limits of impactor sufficiency. The nuclear approach is considered within the context of current capabilities, posing no need to test, as extant and well-understood devices are sufficient for the largest known Potentially Hazardous Objects (PHOs). Results of x-ray sources with realistic spectra as well as blackbody spectra are given, along with some assessment on composition dependence. |
| Databáze: | OpenAIRE |
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