What could potentially be the biggest problem during a human mission to Mars? One NASA study says, surprisingly, that dust could be the number one risk for both humans and equipment. Human explorers could inhale the extremely fine but rough dust particles causing severe respiratory problems, and high winds on Mars could disperse the dust to coat solar panels, penetrate through seals and interfere with machinery. But scientists at the University of Vermont may have come up with a new way to combat dust: acoustic levitation. But will it work on Mars?
The researchers conducted a feasibility study to develop an acoustic dust removing system for use in space stations or habitations on the Moon or Mars. They found a high-pitched (13.8 kHz, 128 dB) standing wave of sound emitted from a 3 cm aperture tweeter and focused on a reflector 9 cm away was strong enough to dislodge and move extremely fine (<2 µm diameter) dust particles on the reflector surface. The sound waves overcome the van der Waals adhesive force that binds dust particles to the surface, and creates enough pressure to levitate the dust, which is then blown away.
The team tested the system on a solar panel coated with mock lunar and Martian dust. The output of the clean panel was 4 volts, but when coated with dust it produced only 0.4 volts. After four minutes of acoustic levitation treatment the output returned to 98.4% of the maximum.
Mars dust, although fine, is rougher that Earth dust, and likely is more similar to the dust that covers the Moon. The thin atmosphere on Mars means dust particles are not as rounded as they would be on Earth and can remain quite sharp and abrasive.
[/caption]
Mars dust, as we have found with the Mars rovers, has a high electrostatic charge, which means the fine dust clings to everything. The dust has severely decreased the efficiency of solar panels on the rovers, and over time has likely caused other problems with the mechanical operation on the rovers as well. We've had several articles here on Universe Today discussing the problems of dust on the solar panels of the Mars Exploration Rovers, and inevitably we get comments from readers suggesting "wiper blades" or other types of cleaning solutions for the solar panels. Amazingly, Mars itself has cleaned the rovers' solar panels several times with gusts of wind from the almost ubiquitous Martian dust devils.
Acoustic levitation could be a solution, as it would be cheap and easily built. But there is a problem, and it is a big one: it will only work when it is sealed inside a space station or other habitation. It will not work where there is no atmosphere (such as the moon) or where the atmosphere is low pressure and thin (such as Mars) because sound is a pressure wave that travels through the air.
So, we might be stuck with having to resort to wiper blades, or devising a way to mimic the dust devils and gusts of wind that have repeatedly benefited the Mars rovers. Unless we can figure out a way to get dust to levitate without sound. Nirvana anyone?
Source: PhysOrg
13 Replies to “Could Mars Dust Be “Levitated” Away?”
Comments are closed.
In the words of Ann Clayborn: “Stop calling it dust. That’s like calling actual dust dirt. They’re FINES.”
Ow, my ears. That video was painful. At least I know I can still hear high frequencies.
Oh, we can do a lot of things, problem is that it is awkward. (Use or neutralize electrostatic charges, or micro-/nano-technology on surfaces, to move dust or alleviate, et cetera.)
The root problem is that Mars is a neglected desert, and the solution to that is terraforming _before_ colonization. 😀
The rovers should have been built with some kind of high vibration feature. The panels could be tilted at a certain angle, then the vibration feature would be turned on that would literally shake the dirt off. Either that, or, some kind of compressed air canisters, positioned at various points on the panels, to blow dust away in jet-bursts.
Another suggestion, it if the dust has magnetic attracting properties, could have been to have a fold-away arm with a magnet disc attached, that could extend and hover over the panels picking up the dust. 🙂
I like this article a lot, fines are going to be more of a problem than we think.
Vibrating the solar panels might work even in a vacuum or near vacuum. You won’t get acoustic levitation, but the particles might bounce along on the moving surface. However, I remember an attempt of mine to coat microballoons all the way around in a parylene coater (which uses low pressures, similar to Mars) by bouncing them on a piezo transducer, and that was a flop.
At low pressures, you might be able to use an ion beam to blow off dust particles. This was to be my Mk II levitator but it never got built.
I suspect the easiest solution might be to follow what dirt bike riders do. They use visors with a series of layers like cling-film, and rip them off as they get covered in mud. We could cover the panels in a thin sheet of material from a roll, and unroll more as it gets dirty.
Race cars (NASCAR in particular) also use windshield film.
You could have a sort of converor that periodicallt moved new film over the panels, while the old film is rolled under and cleaned – in a presurrized acoustic chamber, perhaps.
Richard Kirk Says:
January 27th, 2010 at 5:09 am
“I suspect the easiest solution might be to follow what dirt bike riders do. They use visors with a series of layers like cling-film, and rip them off as they get covered in mud. We could cover the panels in a thin sheet of material from a roll, and unroll more as it gets dirty.”
Absolutely. I had actually thought of this very thing the other day watching a moto. Surely it would be easy-ish to implement, so long as a suitable material could be found with the desirable properties that didn’t attenuate the incoming light much… I must admit though, NASA have probably already thought of this and disregarded it for good reason, but hey….
Cling-Film
I was thinking about that also but I was wondering how much it would effect the panels performance, and also how well it would work in the low temperatures and pressure?
Since martian and lunar dust are electro-statically charged, why not use vibrating mag. fields for levitation? Pulsing the amplitude and polarity of a field in a dispersion beam?
Wire mesh incorporated into spacesuits or spacecraft as ‘antenna’ to attenuate the fields? Or, carbon fibre substrates with embedded conductive carbon nanotubes? Hmmm… now you got me thinking… again! ~@; )
What about a clear, superconducting film deposition? Made in the shade? i.e. low temps inducing superconducting properties then passing low voltage AC to ‘shake’ off the dust?
Dang… I just wish I had an airborne low gravity lab equipped w/turbo molecular vacuum pumps, EM field generators and all the $$ I needed to ‘play’ with these ideas… Hopefully, somebody does who reads these meandering posts? LOL!