Spirit dirtier Options

[djellison]

RAT+Array=Bad idea. There are so many ways it could go dreadfully wrong. If there WAS anything that could be done in that way, they would have done it 1200 sols ago when they were at the 300 Whrs level before Larrys Lookout. There is nothing MER could do to dislodge the dust. I can understand the desperation - but it's just a case of holding tight. That's it.

Doug

[jasedm]

I think nprev has a good point here - the Apollo astronauts complained that lunar dust got into everything during the moon walks; The moon's regolith is quite different to Mars', but Martian soil probably has a component that is mere microns in size, and there must be an electrostatic charge on the rovers relative to their surroundings.

Probably the arrays have a mix of small rock chips, sand, dust, and electrostatically-adhering fine dust covering them, and the cleaning events only remove one or two of these components.

Unfortunately I don't think the rover can do anything in this regard to help itself, and it will probably be the pulverulent panels that will eventually cause Spirit's slow demise before lack of funding, or other mishap.

[Doc]

I agree.....

The best thing the MER team can do is to improvise, be faithful to Spirit and the martian environment.

[BrianL]

grumble...
What Spirit needs to do is find a nice low hanging bush and sidle up under the branches and bear-rub the dust off.
<dream on>

Better yet, find a traffic light. There should be a down on his luck Martian there with a squeegee looking to make a buck. Well, more likely a brush, squeegees don't work too well without water. I mean, we have to be realistic here.

Brian

[Astro0]

Have no fear....I have dispatched a fleet of special craft to save the day!


Ha, ha!
Astro0

[nprev]

Once again, the enormous resourcefullness of UMSF members astonishes me...go get 'em, Astro0!!!

[PaulM]

The Planetary Society MER update from 31/12/2007 includes the following statement:

The other affected instrument is the miniature thermal emission spectrometer, better known as the Mini-TES. “It sits in the belly of the rover, but looks up the Pancam mast assembly, almost like a periscope and there is a series of mirrors, folded optics [it uses],” Callas explained. “Our only meaningful theory is that there is a thick layer of dust on one or more of the optical surfaces.”

The plan to “vibrate” some of the dust off those mirrors, discussed in the November MER Update, is still on. “There's actually a mode we discovered during integration and test of the rovers more than four years ago, where you get a slight instability in the motion control -- the positive feedback hits a resonance. We've actually been able to reproduce that successfully and it doesn't propose a threat to the actuator mechanism, so we're going to try that.”

This made me wonder whether these movements would be sufficient to cause the whole of Spirit's solar panel array to vibrate. Spirit is currently tilted at 30 degrees and in my dreams these vibrations could be used to shake much of the dust from Spirit's solar panels.

[climber]

Got another (very) mad idea, kinda extreme tough.
Put the IDD on the soil as close as possible from the deck. Then if you order Spirit to extand the arm, this will result in actualy lifting the deck. Then release the arm and Spirit will fall back.
The risk is to break the arm and I'm not sure there's enough power to lift the whole Spirit, but I guess the shock would be enough to release some dust.
Don't blame me for thinking at "creative" solutions

[nprev]

Your creativity is noted & appreciated, Climber!

Thing is, I'm still not sure how much of the dust is being held electrostatically, and a jolt wouldn't do much good for dislodging that crap. The winds do a good job, but that also might involve some friction-induced charge transfer as well as sheer kinetics; the place is so damn dry.

[jamescanvin]

This made me wonder whether these movements would be sufficient to cause the whole of Spirit's solar panel array to vibrate. Spirit is currently tilted at 30 degrees and in my dreams these vibrations could be used to shake much of the dust from Spirit's solar panels.

No. They are just going to vibrate the mirror used to point the Mini-TES to try and shake off some dust. I don't know the mass of this mirror, but I think it's fair to say it's negligible compared to the rest of the rover. Hence there will be essentially no vibration of Spirit as a whole.

James

[James Sorenson]

I'm no expert or anything, but since the mini-TES mirrors are located in PMA, when they attempt to vibrate the dust off, isn't there a risk of dust that was on the mirrors just falling onto the mini-TES telescope at the bottom of the PMA?.

[tasp]

Just brainstorming an idea or two;

* We probably haven't noticed a 'node' or something where dustdevil tracks consistently cross, and we would be able to park the rover(s) for an enhanced shot at a convenient cleaning, but in the unlikely event this hasn't been looked into before . . . .

* Any convenient nearby large appropriately spaced boulders we can park between for an enhanced venturi effect to keep the prevailing winds at a higher speed to reduce dust rate accumulation ?

* or parking 'downwind' of a suitable large boulder or cliff and being in a leeward spot of dead air where deposition rate is low?

* How 'supple' is the suspension system for the undercarrriage at this point? Has the dust 'froze up' the shocks yet? Giving the rover(s) a bumpy ride might knock some dust off, but if the suspension system is still isolating the deck from bumps, then this probably won't work.

* any dust free spots nearby that seem to have (as yet) mysterious dust repeling properties? Go park there and figure out what is doing it.

[centsworth_II]

Of course Spirit is not going to go anywhere
until winter is over. So any plans involving
driving -- or much movement at all -- will have
to wait until then. A 30 degree slope in the
hand beats two dust devils in the bush.

[hendric]

How fast does the RAT on the IDD run? In the videos it looks like it's pretty fast. I'm just wondering if maybe we don't need to actually touch the solar cells with the RAT, but instead blow on them from a short distance. It would be an interesting experiment to place the RAT a sucessively decreasing distances to a dust-covered rock, some unbroken duricrust, and to the tracks, to see what kind of results we could potentially get. It might not be something we can try this winter, except maybe on Opportunity.

It would be a nice feature to add to future IDD/RATs to design the cutting blades/brush to generate a little bit of wind that could be useful for the solar cells.

[nprev]

I'd actually prefer a compressed gas blow-off ability, but that's problematic in a lot of ways (weight & gas composition for starters). Dry CO2 would be best, but it'd have to be really dry, or you'd get nozzle freezing in short order; plus, it's heavy.