'Something' Cleaning Mars Rover

bluenirve writes "'Something' has been cleaning the solar panels of the Mars rover Opportunity. "NASA's Mars rover Opportunity seems to have stumbled into something akin to a carwash that has left its solar panels much cleaner than those of its twin rover, Spirit. A Martian carwash would account for a series of unexpected boosts in the electrical power produced by Opportunity's solar panels.""

They looked for the dirt

[Adam9]

When NASA scientists had the rover examine its solar panels for dirt, it replied, "Nothing for you to see here. Please move along."

Yesterday's News.

[Vaevictis666]

Dupe from Yesterday [slashdot.org]

Re: Yesterday's News.

[Black Parrot]

> Dupe from Yesterday

Yeah, but the panels are still being cleaned today!

Re: Yesterday's News.

[elmegil]

Something is cleaning the editor's memory of the past. Too bad it doesn't work more quickly.

Re: Yesterday's News.

[DJStealth]

Actually, they're not being cleaned today.

If the crater does provide a natural, wind-driven car wash then Opportunity's days as a clean machine could be at an end. On 12 December, it drove out of the crater to explore the terrain beyond. "If in three or four months Opportunity is still operating and hasn't had another power boost that would suggest the crater was the key," Erickson says.

At least assuming that the crater is the martian car wash. If this is the case, the rover can always go back to the c

Even Mars has homeless

[Anonymous Coward]

Isn't it clear that homeless Martians have newspapers to clean the panels too?

That Martian is going to get pissed....

[Neologic]

That Martian is going to get pissed when the probe doesn't give him a tip.

Re:That Martian is going to get pissed....

[jellomizer]

Giuliani had to put all of them somewhere.

Re:That Martian is going to get pissed....

[Anonymous Coward]

"Probe."
"Tip."

There's a joke in there somewhere...

Just goes to show...

[Anonymous Coward]

Women are from Mars.

Nitrogen

[panxerox]

I've always wondered why they never put a little bottlie of compressed nitrogen on the rover with nozzels pointed at the panels. Press a switch on earth and pffftt! dust be gone!

Re:Nitrogen

[prisoner-of-enigma]

Perhaps it's because an exploding bottle of nitrogen would probably total the probe. Always consider what failure of the doo-dad would do to the overall mission before including the doo-dad. Dirty solar panels are one thing, shredded panels is another.

Ultrasonic cleaning

[EvilMidnightBomber]

I had almost exactly the same problem when prototyping my robot lawn mower. (crappy pic in profile) The first rev. used optical interrupters to sense a cut grass edge, and these would rapidly become unusable due to dust. I ran through the feasibility of using such an onboard(liqufied) gas tank, but the ratio of functionality to weight is king in any mobile (and especially spaceborne) app and this falls short on that mark (beside being non-renewable). Wipers (and worse yet the geared motor to drive them) are similarly bulky, and unless you're using diamond coated optics,(no water here to lubricate things) wiping the dust eventually produces hazing due to microscratches. The solution I found was to incorporate the equivalent of an ultrasonic parts cleaner. A cheap high-powered motorola peizo tweeter from rat-shack acoustically coupled to the optics support bar and driven at 40khz does an incredible job of knocking off ALL the loose dust, and it's very light weight. The rover could do the same thing by tilting it's panels vertically and then letting rip with the u-sound. About one x-ducer per square meter is all it would take.

Re:Nitrogen

[WhiteBandit]

Hmm, I fubar'd my link. Anyway, my post SHOULD have said:

Or maybe not [cnn.com]:


Steve Squyres, the Mars rovers principal investigator, said the rovers' designers deemed the additional weight of adding wipers or blowers to the solar panels was not worthwhile. Instead they increased the size of the panels to maximize the power input.

Re:Nitrogen

[NanoGator]

"Or maybe $5 windshield wipers would do?"

What amazes me about this suggestion (which has been posted ad nauseum) is the assumption that NASA engineers didn't consider this.

Bum Martian window washer?

[signingis]

Is NASA going to have a stinky, unwashed, unshaven martian approach the camera and ask for change?

I don't know why

[eclectro]

they just didn't put a windshield wiper with a mister on the rovers.

Then there would be water on Mars!

Re:I don't know why

[gnuman99]

Then there would be water on Mars!

s/would/is/

Re:I don't know why

[utexaspunk]

Then there is be water on Mars!

huh?

Re:I don't know why

[gnu-generation-one]

"...then there would be water on Mars!"

Indeed [wikipedia.org]

it's obviously love on mars

[swschrad]

maybe one of the "lost" landers has a crush on opportunity ;) OK, enough slashdot, back to the egg nog....

Beagle 2

[piquadratCH]

So THAT's what Beagle 2 is doing all the time up there...

Design

[FiReaNGeL]

NASA engineers decided not to put wipers on the solar panels, because it would have been too much trouble / added too much weight. I guess they're pretty happy with their decision now, with the 'unexpected' cleaning events...

Re:Design

[Tablizer]

NASA engineers decided not to put wipers on the solar panels, because it would have been too much trouble / added too much weight. I guess they're pretty happy with their decision now, with the 'unexpected' cleaning events...

But the cleaning is limited to one rover and perhaps not permanent. Some speculate it might be due to Opportunity's tilt while in the crater. Now that it is out of the crater, the washing may end.

Nor do they know the impact of wipers on Mars dust. It may make the problem worse for

Re:Design

[Sparr0]

you do realize the cost of sending payload to the martian surface is measured in millions of dollars per ounce right? a 3 ounce arm would NOT have been worthwhile, considering all the extra (redundant) mechincal support it would have required, as well as software.

Explanation

[JustinXB]

http://ars.userfriendly.org/cartoons/?id=20041107 [userfriendly.org]

I didn't get it.

[northcat]

I didn't get that cartoon. What does it mean?

Ummmm....

[TubeSteak]

I totally don't get it.

::Stares at the picture a bit more::

Oh wait.
HAHAHAHA
Brilliant

Re:Explanation

[Lord Omlette]

I don't get it :(

Re:Explanation

[tepples]

I don't get it either. Does "WASH Me" mean something in a Martian language?

Re:Explanation

[cdrudge]

Ok. Here's an explanation. The rover(s) are losing power because dust is settling on the solar collectors. But in one case, there was this magical boost in power output by 5%. The first thing you would think of is that more sunlight is getting to the photo cells. Some Martian kid came by and, with his finger/tentacle/whatever, wrote "Wash Me" on one of the panels, just like kids do here on earth with dirty vehicles.

Business idea

[otisg]

Hm, that's a good business idea.

Applying Occam's Razor ...

[thelen]

C'mon, dust devils? Super wind? Driving at a tilt? Clearly there's a simpler explanation [tvland.com].

I hope they know how it works....

[Fiz Ocelot]

I hope they don't expect this to be a freebie, or else don't expect all the hubcaps to be there next time!

I told them....

[Audacious]

I told those peskey custodians to NOT clean the rover while it was on the set!

Re:I told them....

[meowsqueak]

Yeah, the continuity person really stuffed up big time.

It's nanobots!

[jarich]

That blasted Wesley Crusher has been screwing around with his school projects again!

All hail...

[prisoner-of-enigma]

I, for one, welcome our new cleanliness-obsessed Martian overlords. It will put a lot of streetcorner windows washing bums out of jobs, though.

wind

[roman_mir]

don't forget that something had to put the dust on top of the solar panels in the first place, so the same thing can move it off the rover...

Entropy increases Re:wind

[wadiwood]

driving around could stir up the dust. Coming to a sudden stop (crashing) could tip a fair bit of it off too. That's how I clean my door mat - belt it against a tree or rock.

Mystery solved

[saddino]

As evidenced by this image [yumahouse.com].

It happened to me too

[Magickcat]

A similar phenomena used to occur in my room as a teenager. Perhaps the two occurances are somehow connected.

Re:It happened to me too

[agent dero]

I'm sure the Mars Lander's mom came in, yelled at him for moving so slowly, and sleeping most of the day, then cleaned his solar panels, and left in a huff....

Brilliant!

Whoda thunk it?

[frank_adrian314159]

Where are we going to find the five quarfloos to pay the Martian homeless person with the squeegee?

dust devils?

[jokach]

The article states:
And the researchers suspect the shape of the crater may encourage the development of dust devils or other wind patterns that could help scrub the panels.

The tornado like winds that can be caused by dust devils is something that was discussed by NASA back in April and surely seems like the real answer:

http://www.space.com/scienceastronomy/dust_devils_ 040420.html [space.com]

I'm not sure why they think its such a mystery now ...

to prolong the fun...

[WiPEOUT]

The answer is obvious: the little green men that are following the rovers around and putting photos of a desolate wasteland up to the rover cameras have decided to prolong their fun by cleaning the solar panel with Windex.

Anyone considered this...

[jbwolfe]

Static charge?

maybe...

[No. 24601]

A drunk martian took a piss on our billion dollar mission.

The crater?

[Lispy]

Opportunity climbed a huge crater down and later up again. I could imagine that due to the steep climbing angle some of the sand fell off. My lame theory, i know it's statically loaded and sticky and I know gravity is only a third, but it could be a factor, maybe?

Re:The crater?

[Lispy]

Ok, I just RTFA and found that they mention my great "theory", nevermind. ;-)

watt-hours per day

[aberson]

seems a little redundant

power * time / time = power

900 Watts * hours / day * (1 day / 24 hours) = 37.5 Watts.

Why not just say that to start?

Re:watt-hours per day

[Detritus]

They have to plan operations to work within a daily energy budget. The big yellow thing in the sky disappears at night.

Re:watt-hours per day

[Kiryat Malachi]

Except the Watt *is* an SI unit (the standard SI unit for power, representing 1 J/s). The equivalent Imperial unit would be horsepower, or lbf/s. Further, the joule being a unit of energy, it has nothing to do with this discussion.

I may be an American, but at least I understand the difference between power and energy.

Squeegee guys

[hedley]

The migrated from Houston/W. Broadway and are now working the crater for the holidays.

second time this happens in one week

[alonsoac]

what are the odds?

They keep passing checkpoints

[iabervon]

As anyone who's played a racing car game in the past twenty years can tell you, when you pass a checkpoint, you get more time. As long as they keep completing new areas, they'll keep getting bonuses. On the other hand, if the Spirit team doesn't get moving, they're going to have to put in another quarter pretty soon.

Re:Wind maybe?

[Control Group]

The reason wind isn't the obvious answer it seems like is that the Martian atmosphere is so thin. I remember seeing (on Discovery HD, IIRC) a wind tunnel simulation NASA was doing to study dust devils on Mars. They set up the chamber at Martian atmospheric pressure, then cranked up a fan to blow some insanely high wind speed. The fine dust on the floor didn't even budge; there just wasn't enough air to make anything happen.

The only way they were able to replicate the observed dust devil effects was to toss larger pebbles into the chamber, kicking the dust up into the wind.

Anyway, the point is that wind is still the most probable cause, but it's not quite the obvious slam-dunk that it superficially seems.

Re:Wind maybe?

[ScottMaxwell]

Anyway, the point is that wind is still the most probable cause, but it's not quite the obvious slam-dunk that it superficially seems.

While wind is the most plausible explanation, it is not the most amusing [userfriendly.org].

That contradicts why it got dusty in the 1st place

[cheekyboy]

Dude, if the air pressure is TOO LOW to blow the dust around, then how DID THE DAMN DUST get ONTO THE panels in the first PLACE!?!?!?!

You cant say fact A)
"The wind is not enough to blow the dust off the panels"

and yet say B)
"The panels got dusty because of wind blow dust around the planet"

So which is it?

But we do know mars gets dusty as wild storms do happen, but we havent seen that in any camera footage this year.

Re:That contradicts why it got dusty in the 1st pl

[Kiryat Malachi]

It's actually possible (for A and B to both be true) if the coefficient of static friction is lower for dust-dust contact than it is for dust-panel contact. In this case, the force required to break dust-dust stiction could be lower than wind forces, allowing the wind to kick the dust into the air, while the wind force could in turn be lower than dust-panel stiction, preventing the wind from clearing the panel.

I have no idea if that's how it is, I just like saying stiction.

Re:Wind maybe?

[i41Overlord]

They set up the chamber at Martian atmospheric pressure, then cranked up a fan to blow some insanely high wind speed. The fine dust on the floor didn't even budge; there just wasn't enough air to make anything happen.

Did they decrease the gravity also? Of course not. That's a huge factor right there. We have more than double the gravity of Mars.

Re:Wind maybe?

[Control Group]

Did you read what I wrote? It was dust movement on Mars that NASA was studying. I am aware of this, as were they, which is why I also said that wind was still the most likely cause. No one is claiming that anything other than wind causes the Martian dust storms/dust devils.

I was merely pointing out that it's not unreasonable to be surprised at it happening, since tests replicating as closely as possible the conditions believed to obtain on the Martian surface indicate that it's less likely than it seems.

would wind work

[grahamsz]

We had gusts up to 98mph earlier this week and my car looks as dirty as ever

Re:would wind work

[MightyMartian]

> We had gusts up to 98mph earlier this week and my car looks as dirty as ever

I suspect the dirt that's covering your car is not much like the particulate on the rovers.

Re:hmmm...

[cheekyboy]

You would think they would have built a wiper to sweap the dust off, or maybe some high pressure air hose or fan. Or thy could have added an ability to vibrate the dust off. We all know 'they could have' but they would have also needed approval for this, but they would not get approved because that would mean the project would run on for much longer, meaning more budget money, and no one wants a rover that last for 5 years on the surface. Its all politics, if the engineers had 100% say, they would have desi

Re:hmmm...

[cmowire]

No, it's more the case that the cost, primarily in weight, of adding the required fan, wiper, or other cleaning system outweighs the value added with more scientific instruments. And given that the panels are relatively fragile (remember, every gram of mass has a dollar amount attatched to it) you'd need to be awfully careful -- wipers are out.

Also, it's something else that can fail. Sure, it sounds like a good idea, but if you ruin the solar panels halfway into the base mission because it doesn't work, people start looking really dumb. Or if the shape of grains of martian soil is not quite the same as earth soil and it ends up not working. Or there's something else that might fail, you leave a backup for it out, and then look really stupid when that part fails and you've still got plenty of solar energy.

The biggest problem, of course, is that the designers of the probe are hamstrung by rather unreasonable launch costs that are showing little signs of getting better and are prevented by vast armies of rather stupid anti-nuclear-power whackos from using a 5 year power source. Oh yeah, and most of the NASA budget is reserved for a space shuttle that is far too expensive and has not been able to be retired and replaced due to a variety of issues.

But, in general, it's much better to get a different assortment of tools on a different probe in a completely different location every 2 years, with a chance to have design improvements, instead of having two massive probes that last for 5 years and can only be launched every 10 years.

Re:hmmm...

[Lumpy]

then why do they not take a cue from NASCAR and Motocross and have thin mylar tear offs on the panels? that technology has existed cince 1980.

one on each would ass less than 1/2 gram of weight and using one of the motors that already exists for folding the panels out to perform the tear off would solve the motor problem.

There really is no excuse except maybe that the materials available for the thin tear offs may reduce the output way too much or might react badly with the higher UV index there and yell

Re:hmmm...

[Planesdragon]

Sheesh.

The engineers decided not to build something to shake off the solar panels, because that would make the darn thing heavier -- which woule mean they would have had to leave something else off.

Politics had nothing to do with it.

Re:hmmm...

[Jester99]

You would think they would have built a wiper to sweap the dust off, or maybe some high pressure air hose or fan. Or thy could have added an ability to vibrate the dust off.

I got to ask a NASA engineer about this once in person.

He said they considered it. But then you have to remember that each of these things has moving parts, which are prone to getting dust in them and clogging, or breaking, or whatever. If you wanted, you could also have multiple layers of solar panels and when one got too dusty, it could "molt" and then the fresh panel would be exposed. They've thought of each of these things.

The problem is that they all add complexity and weight. When you're trying to hurtle something at a planet and have it touch down for landing, making the damn thing bulkier doesn't exactly add to reliability.

If your robot vibrates, then that could loosen screws and the whole thing could rattle itself into a pile of scrap metal.

If your robot blows itself off with an air hose, then you need to have a filter system so you know you're not blowing dusty air on it. But filters get clogged, so eventually the hose system would stop working, and the panels would get dusty.

If your robot molts panels, you then need to add extra motors to lift off a given layer. But these are heavy, and could break. Heavier = more power draw to move around. So if the motors malfunctioned, it wouldn't have gone as far as it would've if it only had a single layer of panels -- meaning you'd get less exploring done.

Wiper motors ... same problem.

Nothing political about it.

Re:hmmm...

[cot]

What about several layers of thin clear plastic that's tensioned?

You have each layer held down with tabs,and release them one by one as the cells accumulate dust. The released plastic curls up at one end of the cells when released.

You could probably do this at least several times.

Re:hmmm...

[Jester99]

I'm not an engineer there. I'm a college student. The point I was trying to make was that they thought of several mechanisms by which the surfaces could be restored, and they rejected them all on engineering merits, not political ones.

If you've got newer, better ideas, I'm sure the engineers there would love to have you on board, as, after all, they aren't rejecting their current ideas based on political reasons, but for engineering reasons.

Re:hmmm...

[QuantumFTL]

What about several layers of thin clear plastic that's tensioned? You have each layer held down with tabs,and release them one by one as the cells accumulate dust. The released plastic curls up at one end of the cells when released.

I work for Steve Squyres (the Principle Investigator) and he said that they considered this option as well, and it was prone to failure.

Looks like they made the right call after all!

Cheers,
Justin

Re:hmmm...

[Magus424]

Well we're already polluting it with probes and extra craters ;)

Re:hmmm...

[cot]

Well, I was actually thinking of something that didn't come completely off, but sat off to the side, either crinkled or rolled up. So it'd have to be stretched to cover the cells(hence the "tensioned" part of the original post)

the continues film on rollers idea another person posted is nice too. As long as the thing in front of the cells is clear, how bad can failure be? If it doesn't come off, it's no worse than if it weren't there.

you'd just have to be damn sure it didn't come off completely and jam

Re:hmmm...

[bani]

Yep. works real well too. And it's very reliable in extreme conditions.

Re:hmmm...

[bani]

A transparent layer of plastic which cycles around the cells (goes over the cells, through a slot in the panel, underneath, and back up through another slot) in a conveyor belt fashion. Underneath, you have an array of brushes to clean the belt.

Whenever it gets dirty, you just run the belt to clean it off.

Cheap, lightweight, reliable, and if it fails well then you have the same runtime as if you had no cleaning system at all, so zero overall loss.

Re:hmmm...

[Bronz]

Maybe.... You didn't read the article did you?

"At the time, the team speculated that wind may have swept the dust off the panels or frost may have caused it to clump, exposing more of the panels. ..."

Re:hmmm...

[Anonymous Coward]

Maybe.... You didn't read the article did you?

You're new here, aren't you?

Re:hmmm...

[new_here_arent_you]

You're new here, aren't you? No, I am.

Re:hmmm...

[Squareball]

I think it's some one from the airforce coming out of our secret base on mars to clean off the rover at night!

Re:hmmm...

[thoughtcriminal87]

wait, there's an article?

Re:hmmm...

[DJStealth]

Doesn't frost imply water? (or some other type of liquid that gets frozen?)

Re:hmmm...

[cmowire]

There's no question that there's water ice on Mars, folks have mostly been making noises about liquid water.

But CO2 makes good frost, too.

Re:hmmm...but...

[frovingslosh]

Wind? You'd think that /.ers would know that mars does have an atmosphere, and therefore can produce some kind of wind, which could be blowing sand and dirt all over the panels.

Re:hmmm...but...

[MajorDick]

Not just a little wind a LOT of wind with "storms" being clocked in excess of 200mph (Actually I think much higher)

Ill be honest I always wondered how the planned to keep the rovers upright if one of these storms ran accross the area

Or are the regional to mars , as in equitorial, polar what ?

Don't forget...

[InThane]

...that while the wind speed is higher, due to the lower air pressure on Mars, that increased speed doesn't mean that the wind is actually strong enough to push it over. I couldn't tell you the exact numbers, though.

Re:Don't forget...

[Billy the Mountain]

That's right. A 200 M.P.H. wind on earth at sea level exerts a lot more force than the same speed wind on Mars (at canal level?).

BTM

Re:Don't forget...

[jhagler]

The Martian atmosphere is about 1/100th as dense as the earth's. In that case a 200 MPH wind on Mars would feel like a 2 MPH wind on Earth.

Of course that's if all you are being hit with is gas, as soon as the wind picks up sand it's a very different scenario.

Re:hmmm...

[Moridineas]

Jeez, RTFA :-p That's exactly what they suggest.

Re:hmmm...

[Jugalator]

Yes, that's a possible explanation, although the martian atmosphere is so much thinner than earth, so even with pretty strong wind speeds, it will do significantly less than on Earth.

Re:hmmm...

[Walt Dismal]

Martian gravity is lower than Earth's, and dust should be lighter and hence easier to blow off. Or shake off - couldn't NASA have built in some way to have the vehicle shake itself like a dog? Or at least jerk forward, stop, jerk backwards. At which point the Martians would groan and wait for the probe to start spouting rap lyrics.

Re:NASA Planning?

[Moridineas]

Blind luck had no part in it. If you would have actually bothered to learn anything about the Rover project before back seat quarterbacking you would have quickly realized why they didn't build in wipers or some other mechanism.

However, since you didn't, I'll summarize in brief:

wipers--would increase weight and electrical requirements of the rovers, thereby decreasing lifespan. Also, the wipers themselves would most likely end up scratching the solar panels or embedding detritus into them, thus decreasing

Re:NASA Planning?

[MightyMartian]

The other side to this as well as that they never actually expected the rovers to last as long as they have. These things have been huge successes, and have been operating very well despite a few wrinkles, long past the lifespan the engineers built them for.

You didn't watch enough cartoons as a kid

[PitaBred]

1958 - "Hare-Way to the Stars" [gargaro.com] - I have this on video! A Looney Tunes episode with Bugs Bunny. Marvin plans to blow up the Earth using the Illudium Q-36 Explosive Space Modulator, and Bugs Bunny tries to stop him. Marvin, angry that "that creature" has stolen his space modulator, creates more Martians.
(stolen from the linked site, bolding mine)

Re:Clouds...or not

[JustinXB]

Clouds have been seen before, but there isn't enough water vapor to rain. However, there has been frost in the early martain morning. I forget at which bot.

Re:Self Cleaning Panels

[geekoid]

you mean magic wipers that don't nede anything to power them?

plus the cost of sending up the extra weight.

Re:Self Cleaning Panels

[cheekyboy]

Dude, spring loaded mechanisms, your "ARM" them when you have power, and 'click them' off when your running low, but not on zero.

Ever heard of light weight composits, or plastics or anything, it doesnt need to be strong or thick, just enough to brush of dust well. Or vibrate the damn thing using those things that xbox controllers have and phones have.

Re:Self Cleaning Panels

[Detritus]

Not to mention that they could just make matters worse by smearing the dust around and scratching the surfaces of the panels.

look at me my parent is a FUCKING GENIUS

[loquacious d]

SHUT UP SHUT UP SHUT UP SHUT UP

For serious, who keeps modding this shit up? Is it really still funny? "I, for one, welcome our Soviet grits hot YOU goatse-Beowulf ????? profit run Linux?" Do I get modded up now, too?

Fucking idiots.

Didn't We Already Do This Yesterday?

[TFGeditor]

http://science.slashdot.org/article.pl?sid=04/12/2 2/145246&tid=160&tid=14 [slashdot.org]