The DART spacecraft will impact Dimorphos (the secondary body of the Didymos binary asteroid) around September/October 2021 to test the kinetic impactor deflection method against possibly hazardous Near Earth Asteroids. A comprehensive model was developed to study the outcome of the impact. The goal is to model the short (within the DART-LICIACube framework) and medium (the HERA framework) term dynamics of the system and of the ejecta particles. The expected final output shall be useful to better understand the initial crater evolution and the characterization of the dust environment within the binary system at the time of HERA arrival, exploring also the possibility of the formation of long term stable particles. Starting from different iSALE cratering simulations of the DART impact, 3D representations of the crater are produced. The particles are then propagated with a dynamical model considering non-spherical shapes for both the primary and the secondary bodies, solar radiation pressure and third body direct and indirect perturbations. A first step in the project is the need to understand the influence on the system evolution of a set of sub-models and parameters. Beyond the fine tuning of the whole dynamical model itself, the results of such a study are important to assess the accuracy needed in the measurement of the studied parameters to achieve a good representation and understanding of the whole system. The overall study will concentrate on several different points, such as the influence of the gravity field both in terms of primary body representation (i.e., polihedron vs. analytical approach), of the secondary body shape, of the final post-impact orbit of Dimorphos (circular vs. elliptic), of the shape of the ejected particles (modeled as ellipsoids with different rotation rates), of the location of the impact, etc. In the present work particular attention will be devoted to the study of the effect of the composition of the target on the evolution of the ejecta particles. Different compositions of Dimorphos in terms of material and physical properties (e.g., porosity, cohesive strength of damaged target, layering, etc.) translate into different initial conditions (in terms of initial state vectors and size and numerosity of the ejecta). The effects of these parameters on the ejecta cloud evolution will be evaluated over different time scales. Once the sensitivity analysis will be completed and the relevant parameters identified along with their needed accuracy, a massive simulation campaign is foreseen to model the dynamics of a large number of ejecta over different time spans. Due to the significant computational effort required for this task, only a sample of these results will be reported here. This research was supported by the Italian Space Agency (ASI) within the LICIACube project (ASI-INAF agreement AC n. 2019-31-HH.0).

Influence of the body composition on the evolution of ejecta in the Didymos-Dimorphos binary system

Bertini, I.;Palumbo, P.;
2021

Abstract

The DART spacecraft will impact Dimorphos (the secondary body of the Didymos binary asteroid) around September/October 2021 to test the kinetic impactor deflection method against possibly hazardous Near Earth Asteroids. A comprehensive model was developed to study the outcome of the impact. The goal is to model the short (within the DART-LICIACube framework) and medium (the HERA framework) term dynamics of the system and of the ejecta particles. The expected final output shall be useful to better understand the initial crater evolution and the characterization of the dust environment within the binary system at the time of HERA arrival, exploring also the possibility of the formation of long term stable particles. Starting from different iSALE cratering simulations of the DART impact, 3D representations of the crater are produced. The particles are then propagated with a dynamical model considering non-spherical shapes for both the primary and the secondary bodies, solar radiation pressure and third body direct and indirect perturbations. A first step in the project is the need to understand the influence on the system evolution of a set of sub-models and parameters. Beyond the fine tuning of the whole dynamical model itself, the results of such a study are important to assess the accuracy needed in the measurement of the studied parameters to achieve a good representation and understanding of the whole system. The overall study will concentrate on several different points, such as the influence of the gravity field both in terms of primary body representation (i.e., polihedron vs. analytical approach), of the secondary body shape, of the final post-impact orbit of Dimorphos (circular vs. elliptic), of the shape of the ejected particles (modeled as ellipsoids with different rotation rates), of the location of the impact, etc. In the present work particular attention will be devoted to the study of the effect of the composition of the target on the evolution of the ejecta particles. Different compositions of Dimorphos in terms of material and physical properties (e.g., porosity, cohesive strength of damaged target, layering, etc.) translate into different initial conditions (in terms of initial state vectors and size and numerosity of the ejecta). The effects of these parameters on the ejecta cloud evolution will be evaluated over different time scales. Once the sensitivity analysis will be completed and the relevant parameters identified along with their needed accuracy, a massive simulation campaign is foreseen to model the dynamics of a large number of ejecta over different time spans. Due to the significant computational effort required for this task, only a sample of these results will be reported here. This research was supported by the Italian Space Agency (ASI) within the LICIACube project (ASI-INAF agreement AC n. 2019-31-HH.0).
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11367/106657
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