Mars attacks: How much dust from the red planet is safe to breathe?

NASA has unveiled a proposed guideline for permissible levels of Martian dust that astronauts might inhale during upcoming missions to the red planet. The initiative aims to safeguard the health of future space explorers while allowing engineers ample time to design and test effective air filtration, airlock systems, and suit-cleaning mechanisms.

Fine Martian dust poses unique challenges, as it can cling electrostatically to spacesuits and equipment, possibly carrying hazardous chemicals and minerals that could harm the lungs. To address this concern, NASA's Mars Dust Limit Working Group, including experts like Shaunna Morrison, a planetary scientist from Rutgers University, has proposed an initial health standard of 0.1 milligram of fine Martian dust per cubic meter of air, averaged over 24 hours for exposure periods of up to 30 days.

This limit is a critical milestone for mission designers, providing a measurable target for air handling, filtration, suit cleaning, and habitat design. The group's assessment drew from rover and lander observations, laboratory simulations, and lunar dust research, drawing parallels between Martian and lunar environments. Martian dust, composed mainly of basaltic minerals, iron oxides, sulfates, and perchlorates, presents a significant risk to health if not controlled.

The proposed limit aims to minimize exposure, especially during extravehicular activities when astronauts return to the habitat carrying dust on their suits and equipment. While chromium and manganese are not likely to pose significant risks under the new standard, further research is needed to fully understand the finer details of Martian dust, including its particle size distribution, chemical composition, and biological availability in the lungs.