New Space and Tech

After DART: Using the first full-scale test of a kinetic impactor to inform a future planetary defense mission

By Keith Cowing
Press Release
October 2, 2022
Filed under , , , ,
After DART: Using the first full-scale test of a kinetic impactor to inform a future planetary defense mission
Spacecraft’s view of an idealized spherical asteroid showing a map of �” across the surface. Values are indicated by the color scale at far left. The desired deflection direction �’ is into the page and 40° to the right. (a), left: ejecta response Model 1, equation (23); (b), right: ejecta response Model 2, equation (24).

NASA’s Double Asteroid Redirection Test (DART) is the first full-scale test of an asteroid deflection technology. Results from the hypervelocity kinetic impact and Earth-based observations, coupled with LICIACube and the later Hera mission, will result in measurement of the momentum transfer efficiency accurate to ~10% and characterization of the Didymos binary system.

But DART is a single experiment; how could these results be used in a future planetary defense necessity involving a different asteroid? We examine what aspects of Dimorphos’s response to kinetic impact will be constrained by DART results; how these constraints will help refine knowledge of the physical properties of asteroidal materials and predictive power of impact simulations; what information about a potential Earth impactor could be acquired before a deflection effort; and how design of a deflection mission should be informed by this understanding.

We generalize the momentum enhancement factor β, showing that a particular direction-specific β will be directly determined by the DART results, and that a related direction-specific β is a figure of merit for a kinetic impact mission. The DART β determination constrains the ejecta momentum vector, which, with hydrodynamic simulations, constrains the physical properties of Dimorphos’s near-surface. In a hypothetical planetary defense exigency, extrapolating these constraints to a newly discovered asteroid will require Earth-based observations and benefit from in-situ reconnaissance. We show representative predictions for momentum transfer based on different levels of reconnaissance and discuss strategic targeting to optimize the deflection and reduce the risk of a counterproductive deflection in the wrong direction.

Thomas S. Statler, Sabina D. Raducan, Olivier S. Barnouin, Mallory E. DeCoster, Steven R. Chesley, Brent Barbee, Harrison F. Agrusa, Saverio Cambioni, Andrew F. Cheng, Elisabetta Dotto, Siegfried Eggl, Eugene G. Fahnestock, Fabio Ferrari, Dawn Graninger, Alain Herique, Isabel Herreros, Masatoshi Hirabayashi, Stavro Ivanovski, Martin Jutzi, Özgür Karatekin, Alice Lucchetti, Robert Luther, Rahil Makadia, Francesco Marzari, Patrick Michel, Naomi Murdoch, Ryota Nakano, Jens Ormö, Maurizio Pajola, Andrew S. Rivkin, Alessandro Rossi, Paul Sánchez, Stephen R. Schwartz, Stefania Soldini, Damya Souami, Angela Stickle, Paolo Tortora, Josep M. Trigo-Rodríguez, Flaviane Venditti, Jean-Baptiste Vincent, Kai Wünnemann

Comments: 30 pages, 7 figures. Planetary Science Journal, in press, accepted 2022 September 22
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2209.11873 [astro-ph.EP] (or arXiv:2209.11873v1 [astro-ph.EP] for this version)
Submission history
From: Thomas S. Statler
[v1] Fri, 23 Sep 2022 21:56:02 UTC (3,179 KB)

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