Skip to content

Lunar Dust

It's like dust, or sand, just on the moon right? Wrong. Like most things outside of the planet humans have evolved, developed and adapted upon very successfully, lunar dust (LD) has the potential to be very deadly. It's more like finely powdered asbestos and similarly toxic.

LD Is over four billion years old and is mostly composed of iron, oxygen and silicon. It's been formed by innumerable meteor impacts upon the lunar bedrock, fracturing it frequently over this considerable time period. This fracturing, combined with solar wind and cosmic rays, slowly reduces the size of the bedrock fragments, with LD being classed as particles under 20 µm (micro metres). Some particles can be less than 0.1 µm, with anything 10 µm or smaller being 'breathable'.

A significant percentage of LD particles, because they have not been weathered, smoothed or broken down in any way by rain, ice, wind, extreme heat, the sea, other forces or any biological activity, have both;

  • sharp and jagged edges
  • a large surface area, which along with exposure to galactic and solar radiation, likely increases the surface reactivity of the particles by creating large numbers of dangling chemical bonds and unsatisfied electron valences

These factors, alone or together lead to the following possible health hazards;

  • Inhalational toxicity
  • Potential pulmonary toxicities
  • Ocular toxicity
  • Dermal effects

The following sections deal with these hazards in more detail but do keep in mind that most of these hazards are theoretical, or poorly understood, as studies have not been conducted on the moon itself. There is also a limited amount of LD that has been brought to earth to study and test with.

Effects of Exposure

Inhalational Toxicity

LD Particles that are inhaled, depending on how they are cleared from the lungs, may persist in the body for months or years before they are 'cleared'. The extended time these particles may remain in the body can prompt the release of oxidants, cytokines and growth factors and set off an inflammatory cascade leading to chronic (1) inflammation. This could lead to fibrosis.

  1. frequent, ongoing, long term, extended (osteoporosis, cancer)

The particles may also directly damage the cells of the lung, allowing nanoscopic particles to enter the bloodstream and, eventually, reach other tissues such as the central nervous system (CNS) and heart.

Potential Pulmonary Toxicities

These are theorised to include;

  • asthma exacerbation
  • bronchitis
  • lung disease
  • acute(1) respiratory distress syndrome (ARDS)
  1. rapid, severe, sudden, short term (broken bone, heart or asthma attack)

Ocular Toxicity

This seems to simply be eye irritation, rather than toxicity, which is quite surprising given the highly abrasive nature of LD. This irritation may compound with repeated exposure but such exposure has not actually occurred to date.

Dermal Effects

LD Is abrasive and may damage the skin with sufficient exposure, which may lead to dermatitis and skin sensitivity. LD Is considered to be similar in abrasiveness to commercial sandpaper. Of course, it's unlikely you'd rub it directly on your skin but it may be present in materials and clothing and may find it's way into the confines of a space suit.

References

This entire article is based upon: Pohlen, M., Carroll, D., Prisk, G.K. et al. Overview of lunar dust toxicity risk. npj Microgravity 8, 55 (2022). https://doi.org/10.1038/s41526-022-00244-1.