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Mars Winds Clean Spirit's Solar Panels Again
Titoxd writes "In a blast from the past, NASA reports that Spirit's solar panels have received a much-needed cleaning courtesy of the Red Planet. The report states, 'The cleaning boosts Spirit's daily energy supply by about 30 watt-hours, to about 240 watt-hours from 210 watt-hours. The rover uses about 180 watt-hours per day for basic survival and communications, so this increase roughly doubles the amount of discretionary power for activities such as driving and using instruments.'"
. . . don't forget to pack the broom.
"Who controls the past controls the future. Who controls the present controls the past." -- George Orwell
That's much better than NASA's alternative plan of sending a Squeegee Kid to do the job.
How much longer can this thing go? I mean, it was "designed" to only go a few months, and we are years beyond that. Anyone have a pool on when it will really stop working?
Don't blame me, I voted for Kodos
Weight = money. At $10,000 per pound, it would have been a waste of money for a vehicle designed to last only three months.
If the vehicle were designed to last five years, it might be a different story.
Jesus, can you fucking read? Not even the article, but the summary...
"to about 240 watt-hours from 210 watt-hours. The rover uses about 180 watt-hours per day for basic survival and communications, so this increase roughly doubles the amount of discretionary power for activities such as driving and using instruments."
180wh for survival. They were generating 210wh. Now they're getting 240wh.
210wh-180wg=30wh discretionary.
240wh-180wh=60wh new discretionary.
No wonder you're not a rocket scientist. Or if you are, you're one of those fucks who confused imperial and metric, aren't you?
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0
(Not to be mean), but this might be a case where RTFS would apply.
Their they're doing there hair.
Back in action, let's go for another 4 years...
Ignorance is Bliss -- And the Opposite is True -- Genius is Madness
the 180Wh is what it uses regardless. So the increase from 210 Wh in to 240 Wh in makes for a doubling of expendable energy.
i find your lack of faith in science disturbing!
FTFA:
The cleaning boosts Spirit's daily energy supply by about 30 watt-hours, to about 240 watt-hours from 210 watt-hours. The rover uses about 180 watt-hours per day for basic survival and communications, so this increase roughly doubles the amount of discretionary power for activities such as driving and using instruments. Thirty watt-hours is the amount of energy used to light a 30-watt bulb for one hour.
They are not counting the overhead to keep the thing alive. They've doubled the amount of power available for science etc.
I work for the Department of Redundancy Department.
Maybe next time, NASA should include some type of cleaning devices,
This comes up every time the rovers are mentioned. Here is a detailed explanation why there are no wipers, or any other cleaning device, on the rovers.
We will bankrupt ourselves in the vain search for absolute security. -- Dwight D. Eisenhower
I agree. It would be a shame if the mission ended after five years because of dust covering the solar array. TFA says that after the cleaning only 28 percent of the sunlight hitting the array was getting past the dust. Imagine how much more power the rover could have with a cleaner that keeps that number closer to 75 percent.
Lesson learned. Someone write down to send lens cleaner with the first manned mission to mars.
My computer uses nearly that much power under full load, and it doesn't even have to move!
Convert FLACs to a portable format with FlacSquisher
This thing is cruising around mars...
Not as much as you think.
"As of sol 1736 (November 20, 2008), Spirit's total odometry was 7,529 metres (4.68 mi)."
Not 240 watts; 240 watt-hours. With 24.6 hours per Martian day, that's about 9.75 watts average consumption.
We've proved that the budget rover designs have been the most successful designs we've sent to another planet.
They've been resourceful and far roaming...so why haven't we expanded on the design.
I think we should package up some new rovers. Slightly larger with additional equipment. With one additional design feature. A means to self-clean it's own solar panel.
This way the unit could theoretically operate for near perpetuity.
Hmmmm...couldn't they use electromagnetic effects to minimize weight? Now just hear me out: sit in front of a CRT that's dusty. Now, ground yourself out with a grounding strap or something. Next, pass your grounded hand just barely over the screen without touching it. What happens? The dust on the monitor will now stick to your hand!
Anyway, whatchya think?
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A manned mission to mars would surely come with a human lens cleaner? Maybe they could offer the robotic vehicles roses from a bucket at the same time? (maybe this is a UK phenomenon).
I think it's even more amazing when you consider that it is 240 watt-hours of energy PER DAY. It's actual power usage I'm guessing is much less. If your lights are incandescent, then they probably use that much energy in less than two hours. Damn, why can't our terrestrial equipment be this efficient?
You do realize that the sun doesn't shine the entire 24 hours and 39 minutes in each day?
So you don't get a constant power over the day.
If I have nothing to hide, don't search me
Boy, those things were built!
Cruise is something of an exaggeration... they've gone 13 miles in 5 years, put together. The Lunar Rover missions each went longer than both combined in 3-4 hours, at top speed they'd pass the rovers within the first hour. Semi-stationary crawlers is a more accurate description, but of course they've been loaded up with scientific equipment rather than for showing off.
Live today, because you never know what tomorrow brings
How do you get the dust off your hand afterward (so that it'll be clean for next time)?
"[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz
240 watt-hours, not 240 watts. (Unless you only want to operate for a single hour!) For comparison, 240WH is roughly the energy in a dozen alkaline "D" cell batteries. If the probe is to operate 24 hours* on that power, that's only ten watts on average.
=Smidge=
(*Earth hours, of course)
Only on Slashdot can a post that confuses power (watt) and energy (watt-hour) be modded +3 Interesting.
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
The next one will be; the Mars Science Laboratory will use radioisotope thermoelectric generators.
this is my sig
Well if you want to be like that I would get to point out that if the surface of the rover was able to effect its electrostatic properties the 'dust' would simply fall off wouldn't it?
A loop, by its nature, continues. If that didn't make sense, start reading this sentence again.
I'm not sure a "Radioisotope thermoelectric generators" provide enough power to run the thing without being too heavy to have a hight likelihood of landing intact. Anyways, it's a 90-day mission. These generators are meant for missions longer than that (Viking and Voyager probes).
... there are no homeless people on Mars.
If someone says he and his monkey have nothing to hide, they almost certainly do.
because I don't want to pay $456,784 for a lightbulb :)
on local ridges or some other local high points where they would get more exposure to wind. At the density of Mars' atmosphere, even a tornado wouldn't hurt the rovers. Don't need to stay there for long; just long enough to get electrical generation up past 28%.
Iris-n is being a bit pedantic here. A watt (W) is 1 joule/second. Using terms like watt-hours per day doesn't make much sense to him or her. What iris-n fails to realize is that, at least in the U.S., we tend to measure electricity usage by the kilowatt-hours (kW/h). Since we're dealing with a much smaller scale with Spirit's solar panels, W/h seems a sensible measurement.
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What're we talking about?
You are using English. Please learn the difference between loose and lose; they're, there, and their; your and you're.
Yeah, that's what I was getting at.
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What I really want to see is a glider, or a ballon/lander combo survive that long. Something of that nature would be really useful if it could pop all over.
I prefer the "u" in honour as it seems to be missing these days.
why can't our terrestrial equipment be this efficient?
It can be, it's just too expensive or annoying. My PC has all these high tech power saving features. I've disabled most of them because they're annoying.
Yes, I do realize that. It's you who haven't understood the joke. Allow me to explain.
The watt-hour (and it does not matter if it is earth hours or mars hours, if you missed this joke as well) is a common unity, used when you want to talk about joules but they're too small, 1 watt-hour = 3600 J.
But when you say watt-hour per day, you're being a little redundant, and losing the big numbers on the way. Of course in this example they should not use watts to stay consistent with the surrounding text. But you could use joules all the way and make the joules per day point clearly. 648kJ is not such a difficult concept.
It would have been better if I said 7.5 W on average?
PS: Rereading my post, I've scrambled things, its 24 Wh/d = 1 W.
entropy happens
Easy... brush it off on your shirt.
æeee!
The next rover uses an RTG for power, so there won't be a need for wipers or any other such thing:
Mars Science Lab
I guess the radiator portion of the RTG could get enough dust on it to cut down on its effectiveness, but Mars in general is still pretty cold, so I doubt there is nearly as big of an issue as dust on solar panels.
Dude, calm down. It's just the internet.
A 30W bulb? Wow. The room I'm in now is lit by a single 18W lamp and that's more than adequate. I realise that American homes tend to be more spacious, but seriously - 30W? How large are your rooms?
Real Daleks don't climb stairs - they level the building.
Sure it would, much of the 180Whrs used to keep the current rovers alive is surely to keep components warm enough which means even the 2.1kg SNAP-3B would be more than sufficient since it puts out almost 1300WHrs of heat per day along with 64.8WHrs of electricity which is the amount they have with the newly cleaned cells. Since just the cells in the 1.2m^2 array have a mass of ~1kg, when the frame and battery are considered I'm sure they have at least as much mass as that RTG.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
why can't our terrestrial equipment be this efficient?
It can be, it's just too expensive or annoying. My PC has all these high tech power saving features. I've disabled most of them because they're annoying.
Apparently the feature that turned off the user was left on.
Shai Schticks:"You don't make peace with friends, you make peace with enemies"
...could be hired to work for GM or Chrysler, Toyota
and Honda would be the ones needing a bail-out.
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Most American incandescent bulbs are 60W. I dont think CFLs have really caught on, though I do use one out of 8 or so lamps in my apartment..
How dare you inject a useful, explanatory article into the armchair quarterbacking? I don't know where you think you are, but this is [i]Slashdot[/i], kid. Take that stuff somewhere else.
Oh, you're not stuck, you're just unable to let go of the onion rings.
Well, it certainly wasn't a cost consideration -- we now know that a $3 can of "canned air" would have worked just fine.
I've abandoned my search for truth; now I'm just looking for some useful delusions.
Are you serious? My kitchen alone has about 15,000 lumens of lighting and it's smaller than most that I saw in Europe outside of apartments, and I often find myself wishing for more lighting. Most small (~9m^2) bedrooms have at least 1600 lumens of lighting, with average CFL efficiency of ~65 lumens/watt that means a small room needs about 25W of lighting as a minimum.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
One of Spirit's front wheel motors has stopped, so the drive it backwards.
Opprtunity's arm wont completely contract, so they drive it loose instead of docked.
Both of the RAT grinders have warn out, so they cannot drill millimeters into rock like they used to.
The camera lenses are dusty. Sometime the wind cleans them up a bit.
I am sure there are others.
Quite. If you're using modern lamps, 30W is ludicrously bright. If you're using old-fashioned incandescents, 30W is pathetically dim. Does such a thing as a 30W bulb actually exist in the world?
Real Daleks don't climb stairs - they level the building.
Well, considering the rovers don't move very far very fast, there can't be much practical benefit to find a ridge then move up and down it. When all the wheels worked, the rovers were getting somewhere around 40m a day. Both rovers currently have one or more wheels that no longer work so movement is not something that is easily done by.
Well, there's spam egg sausage and spam, that's not got much spam in it.
'nuff said.
moist (think: Nutty Professor/Merv Griffith makes me moist...)
Will it be the homeless person, or the rover? In any case Rover got a real shiner. And, i feel so... overcome, so excited for the thing. It's wonderful how Mother Nature can provide pleasure in so many small ways. A VOLTAGE boost. Whoda thought...
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
Nerts to your radioisotope thermoelectric generators.
I, for one, would gladly greet our Mutant Martian Overlords.
The Phoenix polar probe landed in late May 2008 and died early November 2008. It was funded for the first 90 days, then for another 90 days. Because it was so far north, it was expected to die in late November due to too short battery-charging hours. An unexpected dust storm covered the panels causing it to die two weeks early. However, there were other portents of doom: Mars went into solar conjunction in late November, so the device would be on its own for three weeks near its death date. I recall just about now its perpetual night at Phoenix latitude. Its expected to accumulate about a one meter of dry ice frost through the winter, which will crush it. Satellites will photograph it periodically.
Phoenix mostly worked as planned. I think about three of the dozen chemical stoves wouldnt open their latches wide enough. The stoves heat the soils to various temperatures and chemically measure the expelled gases. An stove grate shaker shorted out. Phoneix's arm had trouble getting ice samples beacuse the ice was harder than expected. If you dont gather ice flakes quick enough they evaporate and disappear. The soil was much more sticky than expected and balked at going into the stoves.
Maybe next time, NASA should include some type of cleaning devices, so that when the panels get dusty, then a brush or something could wipe the panels. Sure, it's more weight, but it could increase the productivity of the mission.
But we know now that the wind will clean the dust off, so cleaners are not required.
http://michaelsmith.id.au
The Mars Science Lander is two years late and a billion dollars over budget because it has developed lots of new technology. It was supposed to launch during the 2009 optimal planetary configuration, but will have to wait until the 2011 one. The next lander uses a nuclear source and rocket landing instead of airbags. I'm a little fearful all the new stuff may not work as planned. I am also fearful NASA budgetary troubles may still kill it.
We occasionally see the roses in a bucket in the U.S. as well.
If they had just given the rovers a few dollars, I'm sure a squeegee guy would have appeared to clean the panels. Sure they leave streaks, but it's better than nothing.
The cleaning boosts Spirit's daily energy supply by about 30 watt-hours, to about 240 watt-hours from 210 watt-hours...
I would have never figured out that 210 + 30 = 240.
I read Slashdot for the headlines, because the headlines, unlike the articles, are usually original and never duplicated
Anyone interested in the Mars Exploration Rovers' mission should check out Mars And Me, the unofficial diary of a Mars rover driver. Scott Maxwell is blogging his daily work at JPL exactly five years later. A very interesting and well-written look at the day-to-day operations of a truly amazing scientific expedition.
I don't know where you are, but do you REALLY think anybody would read that article? Nobody even reads the main article!
That's a South African thing too, although there it's mobile phone chargers and craft stuff.
Really, it is about time for an update in the Spirit of that classic tale.
Only this time - we have the Opportunity to make it "based on a true story".
Mit der Dummheit kämpfen Götter selbst vergebens
Ok, he made a mistake. But -1 Troll? WTF? There's nothing remotely trolling about this post.
Repton.
They say that only an experienced wizard can do the tengu shuffle.
How about we all stop thinking that we have better ideas than the guys who built these incredible pieces of machinery? /. we have a bunch of armchair engineers believing they could do better?
I mean the designers built two rovers that had to survive a launch from earth, months in deep space, a bouncy landing on another world, and then operate correctly with a 10 minute (Or longer) radio delay.
That is an incredible accomplishment! Then for it to continue to operate for YEARS! I am in awe of the designers.
Now here on
Do you honestly believe that the same people who built these incredible machines didn't think of a solar panel wiper? A can of compressed air? A fan? A compressor?
To the designers: If any of you are reading this. My hat is off to you. Well done!
If I were God, wouldn't I protect my churches from acts of me?
Do you realize how much does a CRT weight?
Exactly! This is Slashdot, so leave the BBCode to the forums and use HTML like a real nerd!
Cus Mars != Moon.
For your first order comparison, just think of the difference in distance to the source of power...
The enemies of Democracy are
Don't need to point the can, just the plastic tube attached to the can that acts as a nozzle. They already have the mechanical apparatus to unfold the solar panel and extend it into place; it can't be that much harder to move the panel around in front of a fixed nozzle. I am underestimating, there is also a valve and control circuit involved. But hopefully they know enough now to include a simple dust off device in the next planetary probe with solar panels. They should also include an IR camera to catch the little martian critter that has been sneaking up in the middle of the night and cleaning the panels... bastard probably expects a tip!
I've abandoned my search for truth; now I'm just looking for some useful delusions.
Doh!
Consider me shamed.
Oh, you're not stuck, you're just unable to let go of the onion rings.
"Working" is relative. There are a handful of single-points-of-failure on the rovers. If these fail, a rover's suddenly gone. However, they could gradually just wear out. They'll probably be declared "unusable" at the point where they don't return enough science to justify the maintenance costs. Thus, it may come down to an economic weighting.
For example, if an additional wheel stops working, then Spirit will be even more hampered than it is now with one bum wheel. That would greatly limit where it could rove and get sun-light to charge its night-heater system. Flat places tend to be boring science-wise.
Thus, they may face a choice of viewing yet more flat-land rocks that all look the same, or end the roving mission and make it a passive weather-station until the point its batteries fail to hold sufficient charge to keep it warm enough at night to not crack a chip.
I'd give it a 40% chance of a gradual retirement, 30% chance of a sudden failure of a pivotal component, and 30% another dust-storm freezing it too death.
Table-ized A.I.
and why doesn't it happen to my car???
Of course, 30 W lights exists. Incandescents in the 30 W range are used for accent lighting, night lights, multi-lamp fixtures, etc. And as for being ludicrously bright, on a film set it is perfectly normal to have multi *kW* halogens and other high end lamps. So, I know at least a few cinematographers who wouldn't even consider 30 W worth of "modern lamps" to be a starting point.
oven light
A republic cannot succeed till it contains a certain body of men imbued with the principles of justice and honour.
That's, "About what are we talking?". Your using English.
Tic-Tac-Toe, Global Thermonuclear War, and relationships all have the same winning move.
I don't get watt-hours. What's wrong with Joules? Or kJ? Why have two units for energy?
Because civil time isn't decimalized. Human beings in mainstream cultures still plan their work time and leisure time in hours, not kiloseconds. For this and other reasons, electric power companies on Earth still sell energy in kilowatt hours, not megajoules (i.e. kilowatt kiloseconds).
For proving there's nothing a good blowjob can't fix! I'll have to e-mail this link to my wife....
There is no mechanism to tear it off on the rover. It doesn't have fingers because it doesn't have hands. It has only scientific instruments on the arms. Also the arms do not reach very far because they only hold instruments. They would have to be re-designed. So instead of valuable weight and space for instruments, you have to get arms, hands, and fingers that can used only periodically.
Well, there's spam egg sausage and spam, that's not got much spam in it.
...like nothing else in the solar system.
Table-ized A.I.
OK, so the OP has confused watts and watt-hours, but is the Troll moderation really fucking necessary?
"It doesn't cost enough, and it makes too much sense."
You wire the panels so that the charge can be manipulated. You don't have any moving parts, or risk of scratching the surface. It uses electricity, but not much, and it could be built right into the panels. It just seems like the wind would have an easier time if the dust was electrically unsticky. please destroy my idea now, ivan
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I am still in awe of the rovers. I can't think of another mission where we have gotten to move around on another planet for so long.
Imagine the team that gets to work on these...every day they get to experience another planet....
I hope it doesn't become boring, but I can't help but wonder if they joke with their significant other:
"Goodbye dear, I'm off to the quarry."
"Goodbye dear, I'm off for another day of looking at rock #SG2351, you know...the one we call the martian phallus. Professor Gretchen has some more ideas about it...."
"Goodbye dear, we get to move a foot to the left today."
"Goodbye dear, we get to move a foot to the right today."
"Goodbye dear, Dr Simon said we get to spin the Rover around today, but we have to ask him first."
"Only one thing, is impossible for god: to find any sense in any copyright law on the planet." Mark Twain
You've got to love how the very first comment on that page helpfully suggests using an air can, and how the rest of the comments mostkeep going for helpful ideas...
"Why couldn't you... ?"
With the answer right in the article above.