The Lunar Meteoroid Ejecta Environment and Potential Hazards to Lunar Landers

Introduction: Meteoroids and near-Earth objects (NEOs) bombard the airless surface of the Moon, generating ejecta that poses risk to assets on or around the Moon. Drawing on impact crater scaling laws [1] and adapting the ejecta distribution from Sachse et al. [2], we have modeled the lunar meteoroid ejecta environment to aid in assessing this risk. This has resulted in the Lunar Meteoroid Engineering Model (LMEEM) [3, 4], which will be included in the next revision of NASA’s Cross-Program Design Specification for Natural Environments [5] and replace the Apollo-era model described in NASA SP-8013 [6].

In this work, we outline various peculiarities of and provide insight about the lunar meteoroid ejecta environment, comparing our results with the previous model (hereafter, SP-8013), and note consequences for mission planning. On average, the mass flux of ejecta is greater than the mass flux of primary meteoroid impacts, albeit at speeds much slower. Due to these reduced speeds, typical shielding strategies for hypervelocity impacts are not as efficient.

References: [1] Housen, K. R., and Holsapple, K. A., (2011) Icarus, 211(1), 856-875. [2] Sachse, M., Schmidt, J., Kempf, S., Spahn, F., (2015) Journal
of Geophysical Research: Planets 120, 1847–1858 [3] Cour-Palais, B. G., (1969) NASA SP-8013 [4] Minow, J. et al. (2022) NASA/TM-20220000562 [5] DeStefano, A. M. (2021) 52nd Lunar and Planetary Science Conference (LPSC) [6] NASA SLS-SPEC-159 Rev. I (2021)