Lunar dirt is as fine as flour but as rough as sandpaper, and thus it became apparent in the early Apollo missions that it would pose a significant problem. It caused mini dust storms in the Lunar Modules when the astronauts took off their spacesuits and clung to equipment, but it could also cause respiratory problems that could prove harmful.
Billions of years of meteoroid impacts have fused topsoil of the Moon into glass, which in turn has been shattered into tiny pieces. Moon dust is almost half silicon glass, while it also contains iron, calcium and magnesium. Owing to its composition, it can be quite problematic. For one thing, it clung to the Apollo astronauts’ space suits, in part due to the static charge in the dust. They would often get into their module covered in the stuff, which was reported to smell like burnt gunpowder as it reacted with oxygen within the Lunar Module.
It caused additional problems for Apollo 17 astronaut Jack Schmitt in 1972, who suffered the first bout of ‘lunar hayfever’ when he inhaled the dust into his lungs. This was a danger to all astronauts, as the dust could have damaged the lungs and other internal organs, but thankfully significant damage was avoided.
The dust also blocked the joints of some of the Apollo astronauts’ suits, making them hard to move in. The dust compacts very easily, which is why footprints from the Apollo astronauts remain imprinted in the Moon, like stepping in talcum powder, and they’ll probably stay on the lunar surface for millions of years until micrometeoroid impacts wear them down.
However, while an annoyance, it was never life threatening. One interesting aspect of lunar dust is that microwaves can melt lunar soil in less time than it takes to boil a cup of tea. A future vehicle employed on the Moon could therefore ‘melt’ the dust into roads and launchpads.
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