March 22, 2007 | David F. Coppedge

Lunar Dust Is Deadly

A significant fraction of lunar dust could pose deadly risks to future astronauts stationed on the moon, a BBC News report says.  About 1-3% of moon dust particles are too small to be coughed up or removed by the cilia lining the respiratory tract.  These would lodge in the lungs and become inflamed.  As in silicosis and asbestosis, the lung responds by building scar tissue around the particles, but this reduces the effective surface of the lungs for oxygen intake.
    The article has a microphoto of a dust grain that is filled with cavities, like swiss cheese.  These would have up to five times the surface area to interfere with the lungs.  Having jagged surfaces, they would be less likely to be captured by the sinus walls because of the way the particles would follow the path of the air.
    Another problem is with iron grains in 10-20 nanometer particles of lunar dust.  These “nano-phase iron” particles could be absorbed directly into the bloodstream and interfere with hemoglobin’s ability to absorb oxygen.  The fine dust was irritating to Apollo astronauts during their brief visits.  It got into everything and clung like powder.  The lunar rovers kicked up roostertails of dust.  Harrison Schmidt got a bout of “lunar dust hay fever” after returning to the lunar module.
    NASA would like to set up camp on the moon once again in the year 2020.  A Lunar Airborne Dust Toxicity Advisory Group has been working on the problems.  The article discusses techniques the team of medical doctors and scientists are developing to mitigate the hazards of lunar dust.  The iron can be extracted with magnets, for instance, and dust can be melted with microwaves into a kind of paved glass.  Robots may have to employ microwave guns, magnets, vacuums and filters to pave the way for human habitation.  Large amounts of lunar soil will need to be collected for a moon base for building materials, oxygen and hydrogen.  These actions might cause some fine dust to levitate above the surface, however, posing threats to scientific instruments and astronaut health.  Extracting and living on the moon’s “toxic” dust will be a major challenge for the next generation of human rovers.

There’s dust on Earth, too, but….  In most cases (except in man-made habitats like mines and in smoke-filled rooms), our bodies are tuned to the geology and geography and atmosphere.  The atmosphere transports large amounts of dust, but clouds and rain cleanse it and allow dust to solidify into rocks or be transported to the oceans.  Meanwhile, our sinuses, mucous membranes and sneeze responses trap and expel much of the dust that enters our airways, allowing most of us to enjoy many decades of healthy breathing.  Pushing the human body outside the envelope is teaching us many things we might otherwise take for granted.  It’s revealing an amazing degree of tuning of the body to its habitat.
    The moon is the same distance from the sun as Earth, but look how different it is.  Nice place to visit, but you wouldn’t want to live there for long.  The lack of sufficient mass to retain an atmosphere and allow liquid water makes all the difference in the world.

Categories: Health, Solar System

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