TOXICITY OF LUNAR DUST FOR HUMANS AT A LUNAR BASE

Several countries have announced their plans to send humans back to the Moon, to establish Lunar Bases for ‘test-beds' and fueling stations for further human missions to Mars and beyond. This grand endeavor obviously necessitates our immediately addressing many problems involving the In-Situ Resource Utilization (ISRU) of lunar materials. However, an unanticipated situation arose during the Apollo Missions with breathing of lunar dust upon the return of the astronauts to the Lunar Module after each EVA. Many of them complained of the strange smell of “gun powder” from breathing of the lunar dust. Armed with our present knowledge of the chemical and physical properties of the lunar dust (<20 µm fraction of the regolith), it has become apparent that there may be extreme toxicity effects to future astronauts upon ingestion of such particles. This has activated several studies on the mitigation of lunar dust problems, a new design of spacesuit, and an efficient air-filtration system.

Perhaps the most important data to obtain for these studies involve the potential toxicity of the finest of lunar dust. In fact, dust particles on Earth have been shown to result in pulmonary diseases such as black lung with miners in general, wherever rock powder is a breathing factor. In the case of the lunar dust, the ultra-fine particulates could be easily embedded in alveolar sacs and ducts of human lungs, and might cause a progressive lung failure. It is therefore of utmost importance for any return of humans to the Moon that the toxicity of lunar dust be explored in detail. Fundamental measurements on size distribution, reactive surface area, and morphology have never been performed until now. This will permit medical researchers to make first-approximations into the possible effects of lunar dust particles to pulmonary disease.

We report SEM studies on lunar dust particles from an Apollo 11 (10084) and a unique Apollo 17 soil (70051). The resolution of SEM is approximately 20 nm. The particle sizes of 10084 and 70051 dust have Gaussian distributions. The reactive surface area of high-porous (Swiss-cheese-type) particle is about 25% higher than that of non-porous particle. In morphology, particles are classified with different shapes like spherical, elongated, irregular, and so on.