High-Speed Boulders and the Debris Field in DART Ejecta
Abstract
On 26 September 2022 the Double Asteroid Redirection Test (DART) spacecraft collided with Dimorphos, the moon of the near-Earth asteroid 65803 Didymos, in a full-scale demonstration of a kinetic impactor concept. The companion LICIACube spacecraft documented the aftermath, capturing images of the expansion and evolution of the ejecta from 29 to 243 s after the impact. We present results from our analyses of these observations, including an improved reduction of the data and new absolute calibration, an updated LICIACube trajectory, and a detailed description of the events and phenomena that were recorded throughout the flyby. One notable aspect of the ejecta was the existence of clusters of boulders, up to 3.6 m in radius, that were ejected at speeds up to 52 m/s. Our analysis of the spatial distribution of 104 of these boulders suggests that they are likely the remnants of larger boulders shattered by the DART spacecraft in the first stages of the impact. The amount of momentum contained in these boulders is more than 3 times that of the DART spacecraft, and it is directed primarily to the south, almost perpendicular to the DART trajectory. Recoil of Dimorphos from the ejection of these boulders has the potential to change its orbital plane by up to a degree and to impart a non-principal axis component to its rotation state. Damping timescales for these phenomena are such that the Hera spacecraft, arriving at the system in 2026, should be able to measure these effects.
Cite
@article{arxiv.2506.16694,
title = {High-Speed Boulders and the Debris Field in DART Ejecta},
author = {Tony L. Farnham and Jessica M. Sunshine and Masatoshi Hirabayashi and Carolyn M. Ernst and R. Terik Daly and Harrison F. Agrusa and Olivier S. Barnouin and Jian-Yang Li and Kathryn M. Kumamoto and Megan Bruck Syal and Sean E. Wiggins and Evan Bjonnes and Angela M. Stickle and Sabina D. Raducan and Andrew F. Cheng and David A. Glenar and Ramin Lolachi and Timothy J. Stubbs and Eugene G. Fahnstock and Marilena Amoroso and Ivano Bertini and John R. Brucato and Andrea Capannolo and Gabriele Cremonese and Massimo Dall'Ora and Vincenzo Della Corte and J. D. P. Deshapriya and Elisabetta Dotto and Igor Gai and Pedro H. Hasselmann and Simone Ieva and Gabriele Impresario and Stavro L. Ivanovski and Michele Lavagna and Alice Lucchetti and Francesco Marzari and Elena Mazzotta Epifani and Dario Modenini and Maurizio Pajola and Pasquale Palumbo and Simone Pirrotta and Giovanni Poggiali and Alessandro Rossi and Paolo Tortora and Marco Zannoni and Giovanni Zanotti and Angelo Zinzi},
journal= {arXiv preprint arXiv:2506.16694},
year = {2025}
}
Comments
47 pages, 14 figures(including 2 animated sequences) 2 tables