http://www.sciencedaily.com/releases/2002/...20611071940.htm



Seems like it might be possible.

The electrostatic based cleanign which I've seen videos off at IAC, and mentioned again at EPSC seems the best way to go about it...no moving parts...thin, light, simple.

Doug

that, or perhaps a French maid minibot

I still think a small compressor, a thin-walled tank (since it doesn't have to hold that much pressure) and a series of lightweight tubes arrayed at crucial spots around the solar panels makes the most sense. A couple of kg mass investment lets you create your own cleaning events.

You could even re-use a tank used during coast for other purposes. All you need is a vessel that can be pumped up to three to four times the ambient atmospheric pressure and then released through the blower pipes. You can use a very small, very light pump, since you won't have to clean your panels but every few hundred sols, so you don't need to spend an awful lot of time or power at any one given time pumping it up.

I still believe such a system could be designed and implemented that only weighs a kg or two, and considering how much of an impact such a system could have on a solar-powered vehicle, it would be well worth the investment.

-the other Doug

O Doug,

I say, here is a working version of what you mean.
Pipes on ...YouTubes

http://www.youtube.com/watch?v=XgGtjNqrdHA

From the "tooting my own horn" department:

Cornell Chronicle online:
New images reveal threatening conditions that two rovers face in giant Martian dust storm

The release includes versions of my tau-image montages for Opportunity which are, unfortunately, already a week old. I posted more up-to-date versions for both Spirit and Opportunity in the blog just now.

--Emily

Horn tooting MORE than justified - it's a brilliant way of showing what's going on. Those dim-suns (sounds like a tasty dish) combined with the dim-skies previously done - they're just face-slappingly good at getting across how much the situation sucks.

Doug

Cool! They really help people visualize it - the problem that often occurs is that because images of darker scenes are often longer exposures or have been equalized, effects like this are often hidden. Great work!

It works because Jim gave me the RADs and because of the awesomeness of IMG2PNG. Thanks Bjorn!

--Emily

We should rename IMG2PNG as "The Bjorn Supremacy."

Grrrrooooooaaaaannnnnnn!!!!!!!!!!!!!!

-the other Doug

GREAT IDEA!!

BONUS: Mount it on a robot arm, and you could also use it to gently blow away dust from RAT'd rocks, blow away dust in bad places (or wheels or vehicle cams), or even blow down into sand layers (digging down), and also check out how crusted the surfaces are, or even the mobility of surface gravels, berries, sand grains, and dust grains.

-Mike

It might be a "GREAT IDEA!!" but whether it's practical or even doable is another matter. There are many great ideas (and an equal or greater number of bad ones) that never make it off the drawing boards or past the animations. Even if one accepts "the other" Doug's characterization of such a cleaning system as merely costing "[a] couple of kg mass," bear in mind that in this business, ounces count.

Too true.

How about a tiltable or foldable solar array? A few flicks or turning it to vertical might be able to shake dust off?

A tilting solution for the array would probably be much smaller and lightweight to add on than a compressor and tank: (worm gear drive?, few bonus hinges and struts?). The will allow some directional tilt (not in all directions). This could also allow the future rover to stay reasonably in place rather than having to find the perfect slope to park. (It might still have to swivel in place to get the right angle in conjunction with tilting the array).

There'd have to be a decent cost/benefit analysis done to see if a solution would justify the weight. But at least we could use the number of times the current rovers needed to be moved into favorable position to help figure the benefit.

-Mike

Building a small, light, low-powered and very reliable compressor that will work in sub-antarctic temperatures and what would be considered a pretty fair laboratory vacuum here on Earth is NOT a trivial engineering task.

My TV screen is vertical...and the dust doesn't fall of. Nor will it fall off if I shake it. Same would probably be true of the rovers.

The answers are RTG's when you can use them - and potentially electrostatic methods when you can't - which have no moving parts at all

Doug

A pithy way of restating this is "a good solution to a problem is to avoid the problem."

Or, as the stale joke goes:

Patient: "Doctor, it hurts my arm when I do this [raises arm]."

Doctor: "Then don't raise your arm. Okay, we're finished here. That'll be $200 for the medical consult."

If you have ceiling fans in your home this problem is even more evident. I have the one in my bedroom running at full speed most nights and it builds up thick dust every couple of weeks. Even the substantial centrifugal forces on the ends of the blades seem to have a negligible effect on the dust. I was making this very observation to my wife this past weekend as I climbed a ladder to clean it off. She said, "You are the only one I know who would notice or care about something like that."

Hmmm. Good points.

But even with an RTG, there will be some dust accumulation where you don't want it: camera lenses (as we're seeing), and in all those itchy nooks and crannies.

-Mike

If it were me, my wife would have been more surprised by the mere fact that I was actually cleaning off the fan.

Fans need to be cleaned?

Got a desktop PC that's been sat on the floor for > a month? Go and look at it's PSU exhaust fan. FILTHY.

Doug

According to the Mrs., I'm only able to notice dust on or orbiting planets other than Earth.

-Mike

OK, I looked and yes, it is filthy, but then it has been running 24/7 for almost 12 months*. If you find your fans are filthy with dust after only a month, you may want to acquaint yourself with Mr. Hoover or Mrs. Dyson a little more often.


* Its annual shutdown for dust clean-out is scheduled for the first Monday every September. This year, that falls on Sept. 3 - my birthday. What fun I will have.

It's worth remembering that an RTG's output can be degraded by dust accumulation on the radiator fins. On MSL, the RTG is angled to (hopefully) reduce such deposition.

Here is an August 29th Planetary Society update regarding the ongoing dust storms on Mars.

http://www.planetary.org/news/2007/0829_Ma...ove_Out_of.html

Dust- phooey. The MERs will live to fight many more sols, and we are richer for the knowledge. What great data from this storm, what invaluable information for the future of Martian UMSF! (Although I admit that RTGs are just plain the way to go on any planetary surface with any atmosphere to speak of, and also anywhere outside the orbit of Mars... )

I'm not sure what the point is in the dust removal discussion. Using the existing design a planned 90 sol mission has lasted 1299 sols and counting. Since we have experienced significant cleaning events in two separate locations, it is fair to assume that such events will occur over much of the surface. Any design add-ons, no matter how clever, introduce more potential failure modes to the system, and with respect to tilting panels etc, the failure would be catastrophic. Given the performance of the solar power system to date the benefit of any add-ons would not seem to offset the associated risks and weight penalties.

O hi Homie, I'm from season 5, can you guess the episode? What are we up to in Whrs now? >300?

Wow -- up to 300 WHrs and we're rejoicing, while at the same time I've been re-reading Squyres' "Roving Mars" and ran across the discussion of Oppy circling Endurance as her first Martian winter approached. The comment is made that she was dropping down to only 500 WHrs in power, which was characterized as "crippling."

My, how we've progressed...

-the other Doug

Remember that the rovers require more power in the winter, and on dust-free nights to keep warm. We've survived on less than 200 for a short time, but it's not clear what we would need to survive winter nights.

Not fully sure of that. Have a look at any picture of Gussev from above and you'll se that Spirit has been landed in a place where we can see A LOT of DD's path.

Emily, in all seriousness, you should submit that to Edward Tufte as an example of a way to present a huge amount of data in a compact and interpretable form.

Aw, shucks. I'm a devotee of Tufte. However, to be worthy of him there should be at least two other kinds of information presented in the same graphic...

--Emily

But the DD do not seem to be the cause of the overnight cleaning events. Also there are no DD at Meridiani, so the cleaning events are likely due to wind gusts rather than a function of DD activity.

Fox News is carrying an AP story on the "very old rovers' HERE.

The story sez, "During the storm, each of the rovers spent a couple of weeks sleeping most of the time."

Didn't they spend a lot more than a couple of weeks sleeping most of the time?

> Also there are no DD at Meridiani...

That is a rather silly theory to postulate. We see dust devils and dust devil tracks at Gusev because there is abundant dust that is mobile and this makes the dust devils and tracks visible. At Meridiani, there is much less dust available because of the blueberry 'desert pavement' that armors and protects the subsurface from supplying mobile dust. Just because we can't see 'em does not mean that DD aren't here...

What you are saying is dust devils cannot be seen in Meridiani because there is no dust there, but it doesn't mean that there are no dust devils there. Don't dust devils require dust by definition?

Dust devils don't require dust to form (at least to my poor knowledge), it's just their manifestation in which they kick up dust that earned them that name.

Perhaps an overlooked update on Mark Lemmons webpage

http://www.lpl.arizona.edu/~lemmon/mer_dd.html



So long Dust Storm 07

Right, dust devils are wind spirals or mini tornados that only are visible when they kick up dust.

This comes from the Victoria Crater Panoramas topic. I am replying here because it seems to better fit this topic.
That question really made me curious. I found pre- and post-storm pancam images of the central ripples from sols 953 and 1344. The two views were from quite different positions, so it was difficult to make a perfect flicker comparison animation due to the different perspectives. I adjusted them to overlay as best I could.

There is a bit of motion between some areas, but I am sure that is only due to some remaining perspective difference that I couldn't remove. I can't rule out small scale changes beyond the resolution of these images, but there seems to be no significant change due to the storm.
Click to view attachment

Thanks for that, Rocker! I had the same thought and also compared the old and new dune images. Like you I couldn't see any changes beyond what was probably perspective differences. Also, even if we had exactly the same viewpoint, I could imagine lighting differences mimicing slight shifts in the dunes, so you'd have to be very careful.

Split posts on making colour images from monochromatic images taken under differing illumination to a new thread.