One of the last times we wrote an article about a technology that can remove moondust from clothing, we opened it with a famous Star Wars meme line. That also means we should probably avoid subjecting it to everyone here again. However, the fact that we’ve had the chance to use it more than twice recently proves that moondust removal is a problem that has attracted a lot of attention in recent years. Artemis, NASA’s program to return to the moon this decade, is the cause of much attention as there are still many problems to be overcome. Some of these could be solved by a technique developed by a team at Washington State University (WSU) that uses each kid’s gas they can use to pound nails with bananas – liquid nitrogen.
Most likely, there will be better tools than bananas for driving nails in every upcoming lunar mission – if there are any nails at all. But apparently blasting surfaces coated with lunar dust with liquid nitrogen removes up to 98% of the dust intentionally embedded in a mock space suit.
One reason for this is moondust’s impressive ability to electrostatically stick to almost anything. The WSU press release compared their attachment to that of packing peanuts, but with much darker health effects that could include a disease like black lung if exposed to it long enough.
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Watch liquid nitrogen in action in this video from the experimenters
Credit – WSU Voiland College of Engineering and Architecture YouTube channel
That alone would be reason enough to try to find a way to remove it from materials that could make it into any permanent moon base. But lunar dust is also particularly abrasive and tends to damage parts of the Apollo astronauts’ spacesuits, particularly at the relatively soft and malleable seals. Since these are vital to keeping breathing gas in and the deadly vacuum of space out, it’s all the more important to ensure dust doesn’t degrade the Artemis mission’s spacesuits to the point where it could become potentially dangerous.
Unfortunately, to solve the problem on the Apollo missions, the astronauts used a technology that wasn’t even considered advanced in the 1960s – a brush. The brush itself could also negatively affect the spacesuit’s materials, and it was abysmal at actually removing the dust particles. So enter WSU’s liquid nitrogen technology.
Behind this idea is not so much a new technology as a new use for an old one. Liquid nitrogen has been around for years, but when applied to a spacesuit significantly warmer than itself, it triggers a phenomenon known as the Leidenfrost effect. In everyday life, this is most familiar to you when a chef pours cold water onto a hot griddle—or if you’ve ever been to a hibachi restaurant. The temperature difference causes the liquid material to bead up and try to leave the surface as quickly as possible.
The focus of these preliminary tests was a self-made space suit that was coated with lunar dust, exposed to a vacuum and then treated with liquid nitrogen.
Credit – WSU/Wells et al.
However, when the liquid nitrogen beaded on the spacesuit material, they encapsulated the lunar dust particles and forced them off the surface of the material, overcoming their electrostatic adhesion by simply enveloping them completely in liquid. After proving their original point, the researchers needed to prove it would work on the moon.
One of the easiest ways to do this would be to do this in a vacuum, which is exactly what they did. Surprisingly, the sprayer performed better in a vacuum than in the regular operating environment on Earth. However, more work needs to be done to test if it would work in the moon’s gravity.
To support this work, WSU researchers are applying for grants to further their research and have already taken home an award from the 2022 Breakthrough Innovative and Game-changing Idea Challenge. Further modeling will also be part of the deal, as no good research on this topic can happen without a valid, complex fluid dynamics model – or a Star Wars reference.
WSU – Liquid nitrogen spray could clear stubborn lunar dust
Wells et al – Lunar dust removal and material degradation by liquid nitrogen sprays
UT – Figuring out how to breathe the moon’s regolith
UT – Finally! A solution for dealing with sticky moondust
UT – Lunar dust is still one of the biggest challenges for lunar exploration
Dust blasted away by a stream of liquid nitrogen.
Credit – WSU/Wells et al.