Shielding the Moon: How NASA Models Micrometeoroid Threats to Future Artemis Bases

NASA’s Artemis program aims to return astronauts to the Moon and establish a permanent base at its south pole. But surviving long-term on the lunar surface means dealing with an invisible hazard: micrometeoroids, tiny bits of space debris traveling faster than bullets. In this paper, Daniel A. Yahalomi and collaborators estimate how often these particles might strike a lunar base, and whether modern shielding can keep future habitats safe.

Background and Motivation

The Artemis Base Camp will face numerous challenges, from radiation to extreme temperature swings, but one of the least understood dangers is the micrometeoroid environment. These dust-sized particles, impossible to detect before impact, can damage structures or equipment over time. Since NASA’s current plans for Artemis-era shielding are still in development, the team examined how effective existing “Whipple shields” might be on the Moon. A Whipple shield works by placing a thin bumper layer in front of the main wall; when a high-speed particle hits the bumper, it vaporizes, spreading out its energy before reaching the main structure. Using known material properties, Yahalomi’s team estimated that particles larger than about 0.12 cm across could punch through such a shield.

Monitoring Lunar Impacts

Detecting micrometeoroid impacts on the Moon is notoriously difficult. Current techniques, such as tracking new craters with NASA’s Lunar Reconnaissance Orbiter, observing optical flashes from Earth, and measuring topographic changes, are sensitive only to larger meteoroids, typically centimeters to meters across. While these studies confirm that the Moon is constantly bombarded, they cannot track the smaller, more frequent impacts that would concern a lunar base. NASA’s upcoming LUMIO CubeSat, planned for launch in 2027, will help by watching for faint flashes on the lunar farside, but even that will have limited resolution. Thus, to understand the micrometeoroid environment relevant to Artemis, researchers turn to computer models rather than direct observation.

Modeling Micrometeoroid Impacts

To simulate the impact environment, the authors used NASA’s Meteoroid Engineering Model 3 (MEM 3), which predicts how many micrometeoroids hit a spacecraft, or in this case, a stationary base, over time. MEM 3 accounts for gravitational focusing by Earth, which slightly increases the number of meteoroids reaching the Moon’s near side, and the shielding effect of planetary bodies that block certain trajectories. The team modeled 1,000 hypothetical base locations evenly spread across the Moon, each the size of the International Space Station (about 100 meters long and wide, and 10 meters tall). This allowed them to map impact rates across latitudes and longitudes for different meteoroid mass ranges.

Results: The Impact Landscape of the Moon

The model predicts that a base without any shielding would experience roughly 15,000 to 23,000 micrometeoroid hits per year from particles between one millionth of a gram and ten grams. The impact rate varies with position, lower at the poles and higher near the lunar region that faces Earth. This asymmetry shows that Earth’s gravity pulls in more meteoroids than it blocks, increasing the flux on the near side. Importantly, the lunar poles see about 1.6 times fewer impacts than equatorial regions, supporting NASA’s decision to build Artemis Base Camp near the south pole.

Results: Shielding Effectiveness and Critical Mass

Using a combination of Whipple shield parameters and MEM 3’s speed distributions, Yahalomi’s team found that only particles heavier than about 0.07 grams (the “critical mass”) could penetrate the shield. When this threshold was applied to the model, 99.9997% of incoming particles were too small to cause damage. That means a typical base would see only about 0.03 penetrating impacts per year, or one every few decades. Even in these rare cases, the poles remain the safest zones, with one significant impact expected roughly every 40 years.

Implications for Artemis and Beyond

By combining MEM 3 simulations with the well-known Grün relation, which describes how meteoroid flux depends on particle size, the researchers created a continuous model for evaluating different shield strengths. This framework can guide engineers designing future lunar habitats, helping them determine how thick or layered a shield must be to meet safety standards.

Conclusion

Yahalomi and colleagues conclude that the lunar south pole is not only scientifically valuable but also safer for long-term operations. Earth’s gravity slightly increases impact risk on the near side, but current Whipple shields reduce this threat by five orders of magnitude, enough to make a permanent lunar outpost feasible. The study shows that with careful modeling and engineering, humanity can safely weather the steady drizzle of space dust as it builds its first foothold beyond Earth.

Source: Yahalomi