Effects of impact and target parameters on the results of a kinetic impactor: predictions for the Double Asteroid Redirection Test (DART) mission

The Double Asteroid Redirection Test (DART) spacecraft will impact into the asteroid Dimorphos on September 26, 2022 as a test of the kinetic impactor technique for planetary defense. The efficiency of the deflection following a kinetic impactor can be represented using the momentum enhancement factor, Beta, which is dependent on factors such as impact geometry and the specific target material properties. Currently, very little is known about Dimorphos and its material properties that introduces uncertainty in the results of the deflection efficiency observables, including crater formation, ejecta distribution, and Beta. The DART Impact Modeling Working Group (IWG) is responsible for using impact simulations to better understand the results of the DART impact. Pre-impact simulation studies also provide considerable insight into how different properties and impact scenarios affect momentum enhancement following a kinetic impact. This insight provides a basis for predicting the effects of the DART impact and the first understanding of how to interpret results following the encounter. Following the DART impact, the knowledge gained from these studies will inform the initial simulations that will recreate the impact conditions, including providing estimates for potential material properties of Dimorphos and Beta resulting from DARTs impact. This paper summarizes, at a high level, what has been learned from the IWG simulations and experiments in preparation for the DART impact. While unknown, estimates for reasonable potential material properties of Dimorphos provide predictions for Beta of 1-5, depending on end-member cases in the strength regime.This work was supported by the DART mission, NASA contract No. 80MSFC20D0004. This work has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 870377 (project, NEO-MAPP) and from the French space agency CNES and the CNRS through the MITI interdisciplinary programs. We gratefully acknowledge the developers of iSALE-2D (www.isale-code.de) including Dirk Elbeshausen, Boris Ivanov, and Jay Melosh. This work was supported by the Italian Space Agency (ASI) within the LICIACube project (ASI-INAF agreement AC n.2019-31-HH.0; C.B. and C.M.S. appreciate support by the German Research Foundation (DFG) project 39848852. Alice Lucchetti, Maurizio Pajola, and all other coauthors from the LICIACube team acknowledge financial support from Agenzia Spaziale Italiana (ASI, contract No. 2019-31-HH.0). J.O. and I.H. were supported by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”—Centro de Astrobiología (CSIC-INTA). They are also grateful for all logistical support provided by Instituto Nacional de Técnica Aeroespacial (INTA). Parts of this work were performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. LLNLJRNL-831475. This work was supported in part by a Chick Keller Postdoctoral Fellowship through the Center for Space and Earth Science at Los Alamos National Laboratory. Parts of this work were supported by the Advanced Simulation and Computing (ASC)—Threat Reduction and ASC—Planetary Defense programs. Los Alamos National Laboratory, an affirmative action/equal opportunity employer, is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the US Department of Energy under contract 89233218NCA000001. LA-UR-22-21164