Physical and Biological Hazards of Lunar Dust and Their Impact on Habitat and Space Suit Design

Lunar dust is highly abrasive because of the space environment in which it formed. On Earth, while dust is a nuisance, it does not adhere to surfaces to the same extent as lunar dust, which is devoid of water and thus capable of significant electrostatic charging. Lunar dust and soil grains are irregularly shaped and stick to fabric more tenaciously than would terrestrial dust. Lunar dust may be hazardous to people when it finds its way inside space suits or into crew living quarters. The finest fraction of lunar soil, less than three micrometers in diameter, can lodge in the lungs when inhaled. Preliminary studies suggest that the inhalation of lunar dust may pose a non-negligible health hazard. The Apollo crews were only exposed for a few days at most, but future crews may be exposed for weeks or months. The nanophase iron in lunar dust may also pose a health hazard, because the reduced metallic iron present in most glassy particles and on mineral grain surfaces can be dissolved in the lungs and then move into the bloodstream, possibly reaching toxic levels. An airlock, suit lock, or mud-room is crucial for reducing the amount of dust to which crewmembers are exposed. Moreover, air filters within habitable areas should be designed to capture particles that are less than 3 microns in size. The air quality within space suits as well as in the vehicle or habitat should be monitored and managed in order to minimize risk to humans of lung diseases or blood poisoning from excess iron. Suit designers must be cognizant of the difficulties of removing lunar dust from traditional fabrics using brushes or other ordinary methods, and they must have a good understanding of the way that lunar dust can affect bearings and seals in space suits.