As a wise man once said, “I don’t like sand. It’s coarse and rough and irritating – and it gets everywhere”. The same could be said for another material in our solar system – dust.
The kind of dust present on the moon is even more annoying than the grains that bothered Anakin Skywalker on Tatooine. It is constantly bathed in solar radiation, smells like spent gunpowder, and can cause allergic reactions, as it did in some of the Apollo astronauts. It’s also notoriously difficult to clean off of surfaces. Now a team of scientists at the University of Colorado at Boulder think they have a solution that would remove lunar dust without harming the material it’s attached to. And they would do this by using a tool that sounds like it’s straight out of Star Wars – an electron beam.
Electron beams aren’t actually as sci-fi as they sound. They have been well understood since the 1950s, and are widely used in semiconductor manufacturing processes. They consist of a device that shoots out a low-energy (ie safe) stream of negatively charged particles.
Lunar dust itself is also negatively charged, caused by the constant solar radiation it is subjected to. This is part of the reason it’s so hard to clean – the small electrostatic buildup caused by the radiation makes the dust extremely clingy. This is similar to how a feather can stick to your hand in winter via electrostatic attraction. Or a cat can be completely surrounded by styrofoam pellets.
What Benjamin Farr and his colleagues at CU Boulder’s Laboratory for Atmospheric and Space Physics, the University of Iowa, and JPL realized was that they could use an electron beam to negatively charge a base material. Negative charges repel each other, so any negatively charged lunar dust that is present on the material should slough itself off.
In order to test this theory the team were unfortunately not able to take a prototype to the moon. However, they did manage to get their hands on a substance called “lunar simulant”, which is commercially available from NASA, and is designed to be as close as possible to actual lunar dust.
The researchers sprinkled the dust over various surfaces that could potentially be part of a future lunar mission. They then put the dust-coated material in a vacuum chamber (which obviously wouldn’t be needed on the moon) and then pointed an electron beam at them. As predicted, the dust just fell off the material. The team was able to clean about 75-85% of a dusty surface with their electron beam.
That’s still a far cry from being perfect, but it’s a lot better than the manual hand scrubbing that is currently part of any future lunar astronaut’s cleaning repertoire. And the research team still isn’t done yet. There’s still a lot of research to go before even a prototype makes a trip on any lunar mission. However, Dr. Mihály Horányi, one of the co-authors envisions a future where astronauts can simply leave their space suits in a special room, and they can then be bathed in an electron shower that flushes all the dust right off of them. Who knows, maybe that technique would work on Jedi robes too.