A recent paper on the Toxicity of Lunar Dust highlights one of the problems that need to be solved for long-term space settlement.

NASA’s been studying the dangers of dust for some time. The primary concern with lunar dust is silicosis, a condition which occurs when fine particles become embedded deep within the alveolar sacs and ducts where oxygen and carbon dioxide gases are exchanged. Other parts of the body may also be affected. The lunar dust is so fine that particles can pass through the capillaries and into the blood stream, making their way to vital organs including the heart, liver, and brain. The body’s immune systems are largely helpless against the dust particles, which are so sharp that white blood cells are destroyed when they attempt to engulf them.

Even if dust is not inhaled, it can still cause skin and eye irritations.

While lunar dust is primarily a mechanical irritant, Martian dust is expected to be both an irritant and a chemical poison. The Martian regolith may be a strong oxidizer comparable to undiluted lye or bleach, capable of burning human skin. Dust storms and static electricity may create hydrogen peroxide that falls to the surface as corrosive snow. If that wasn’t bad enough, the dust has also been found to contain trace amounts of toxic metals including arsenic and hexavalent chromium.

NASA is working on ways to mitigate these hazards. The solution will no doubt involve extreme attention to cleanliness and strict isolation from the lunar/Martian environment. Nevertheless, accidents will still happen from time to time.

As we learn more about the toxicity problem, perhaps it’s time to revisit the question which Princeton professor Gerard K. O’Neill asked in 1969: “Is a planetary surface the right place for an expanding technological civilization?” After examining the problems of energy, gravity, and resources, Dr. O’Neill concluded that artificial structures (very large space stations) were a more logical location for long-term space colonization. His ideas were popularized in the book The High Frontier: Human Colonies in Space. Perhaps the Moon and Mars will be developed as mining sites and research bases, while the real settlements are built in free space.