Micrometeoroid Impact Rate Analysis for an Artemis-Era Lunar Base

TL;DR

The paper addresses micrometeoroid hazards for Artemis-era lunar bases by leveraging NASA's MEM3 to compute location-dependent incident and penetrating impact rates for a base sized ~100 m × 100 m × 10 m. It maps the full lunar-surface flux, shows poles experience fewer impacts while the sub-Earth region sees the highest flux, and demonstrates that Earth’s gravitational focusing dominates over geometric shielding. By applying a conservative Whipple-shield model, the authors estimate a median critical mass of $m_{\text{crit}} \approx 10^{-1.16}$ g and find that ~99.9997% of incoming particles are below this threshold, reducing penetrating impacts to ~0.024–0.037 yr$^{-1}$ (roughly one every 27–42 years) with poles again experiencing fewer penetrations. They further scale MEM3 results with the Grün relation to provide a continuous proxy for shielding performance, offering a practical tool for shielding design across arbitrary mass thresholds. The findings support prioritizing lunar poles for sustained habitation, quantify shielding efficacy to five orders of magnitude, and point toward future enhancements including regolith-based shielding and transient-meteoroid events to refine mission-risk assessments.

Abstract

NASA's Artemis Mission aims to return astronauts to the Moon and establish a base at the lunar south pole. A key challenge is understanding the threat from micrometeoroid impacts, which are too small to monitor directly. Using NASA's Meteoroid Engineering Model 3 (\texttt{MEM~3}), we estimate micrometeoroid impact rates on a base comparable in size to the International Space Station (100\,m $\times$ 100\,m $\times$ 10\,m). We find that a lunar base would experience $\sim$15,000--23,000 incident impacts per year by micrometeoroids with a mass range of $10^{-6}$--$10^{1}$~g, depending on location -- with minima at the lunar poles, a maximum near the sub-Earth longitude, and a factor of $\sim$1.6 variation between the two. To assess the mitigating effect of protection systems, we present a functional relationship describing the number of impacts that penetrate the shielding as a function of the minimum meteoroid mass capable of penetrating the shield -- the ``critical mass.'' We estimate that state-of-the-art Whipple shields protect against $\sim$99.9997\% of micrometeoroids. By re-running \texttt{MEM~3} with a minimum mass equal to the critical mass of modern Whipple shields, we determine that a shielded lunar base would experience $\sim$0.024--0.037 penetrating impacts per year -- again with minima at the poles and a maximum near the sub-Earth longitude. These results indicate that (1) the lunar poles are optimal for sustained habitation, (2) gravitational focusing by Earth dominates over its geometric shielding for this micrometeoroid flux, and (3) current shielding technology can reduce micrometeoroid threats by nearly five orders of magnitude, making long-duration lunar habitation feasible.

Figures (6)

• Figure 1: Whipple shield concept from christiansen2003.
• Figure 2: Coordinate system used in the MEM 3 simulations for [left] full lunar surface and [right] zoom-in on the lunar base.
• Figure 3: Mollweide (left) and polar (right) projections of the incident micrometeoroid impact rate on the lunar surface, representing the complete $10^{-6}$--$10^{1}$ g mass range in MEM 3. The "x" marks the sub-Earth point on the lunar surface.
• Figure 4: Impact velocity averaged over all base locations; the derived $m_{\rm crit}$; and the $m_{\rm sample}$/$m_{\rm crit}$ distributions.
• Figure 5: Mollweide (left) and polar (right) projections of the penetrating micrometeoroid impact rate on the lunar surface, representing the $10^{-1.16}$--$10^{1}$ g mass range in MEM 3, for which the most dense micrometeoroids would penetrate current Whipple shielding. The "x" marks the sub-Earth point on the lunar surface.