Forgot your password?
typodupeerror
Space Science

Mars Rovers Update 320

Posted by michael
from the never-will-play-the-wild-rover-no-more dept.
BoldAC writes "CNN is reporting that engineers will upload a software hack to decrease the recent power drain plaguing the rover Opportunity. The hack works by reducing the power supply to a poorly functioning switch." p3tersen writes "Opportunity has photographed a blue martian sunset (it's blue because of the optical scattering properties of dust in the martian atmosphere). In other news, the rovers are beginning to experience power supply problems due to the accumulation of dust on their solar panels."
This discussion has been archived. No new comments can be posted.

Mars Rovers Update

Comments Filter:
  • Solar problems (Score:5, Interesting)

    by LotsaCaffeine (312054) on Saturday February 28, 2004 @04:42PM (#8418556) Homepage
    NASA should have installed wiper blades on the solar panels.
    • Re:Solar problems (Score:2, Interesting)

      by MikeCapone (693319)
      NASA should have installed wiper blades on the solar panels.

      I know you are joking, but I'm actually surprised that they haven't thought of a way to keep the solar panels clean.

      I mean, they can get the thing to mars, they should be able to do that, no?
      • Re:Solar problems (Score:3, Informative)

        by r00zky (622648)
        For an easy solution see: helmets of Formula One drivers.
        • Re:Solar problems (Score:4, Insightful)

          by Anonymous Coward on Saturday February 28, 2004 @04:49PM (#8418606)
          Every easy solution has a problem. The problem with this one is that the Mars rovers don't have any arms to rip the layers off.
          • Re:Solar problems (Score:4, Interesting)

            by r00zky (622648) on Saturday February 28, 2004 @04:57PM (#8418662)
            A thread attached to a corner of every plastic sheet running diagonally to the opposite corner and an electric motor that activates when the sheet is dirty.
            Stack 10 sheets of this and voila, lifetime of the rover multiplied x10.
            • Re:Solar problems (Score:4, Insightful)

              by Anonymous Coward on Saturday February 28, 2004 @05:06PM (#8418714)
              If only life were so simple, you'd be working for NASA...

              How is the motor supposed to pull the correct wire (you wouldn't use thread)? Ten different motors?

              What do you do with the tear-off once you pull it? Leave it clumped at the bottom or just have hang around trailing behind the rover or right on top of the panels? Cut the wire you say? Kind of difficult to do that if you rolled the wire up on a spool with a motor. Going to need ten pyros for that.

              Don't forget that you have to pack all of this onto the rover and fold up the panels. Better hope your wires don't tangle up and prevent the panels from unfolding.

              All of this stuff takes up weight and adds complexity. Do you really want to do all of that?

              • Re:Solar problems (Score:5, Informative)

                by Anonymous Coward on Saturday February 28, 2004 @05:27PM (#8418852)
                How is the motor supposed to pull the correct wire (you wouldn't use thread)? Ten different motors?
                A simple set of 10 mechanical gears made of plastic and stacked in a row would do this. The driving gear jumps from first to last as needed. My printer does something similar to this everyday to a precission of 720 dpi so...

                What do you do with the tear-off once you pull it?
                Cut the wire between the plastic sheet and the gears that rolled the wire. No need to have 10 cutting devices, since only one wire will get rolled at a time.

                Don't forget that you have to pack all of this onto the rover and fold up the panels.
                Implement one of these in each fixed panel, not in the panels as a whole.

                All of this stuff takes up weight and adds complexity
                Sending 2 probes to Mars and getting scientific data back is waaaaay more complex than this. And the weight... it adds a little more $$ for fuel, but the result is a _much_ longer lifetime.
                • Re:Solar problems (Score:5, Informative)

                  by GileadGreene (539584) on Saturday February 28, 2004 @08:59PM (#8419972) Homepage
                  It's not a case of a few more $$ for fuel. It's a case of being able to launch at all. The rovers BARELY made it under the max launch mass. They were even over the max at some points in the program, and were stripping off mass whereever they could. Besides, in the space business additional mechanisms are frowned upon due to both the difficulty of designing a mechanism to work in the space (or martian) environment, and the inherent decrease in relaibility of the overall system. MER already has far more than mechanisms than is usual for a space mission.
                • Re:Solar problems (Score:3, Insightful)

                  by Dun Malg (230075)
                  Don't forget that you have to pack all of this onto the rover and fold up the panels.

                  Implement one of these in each fixed panel, not in the panels as a whole.

                  Another minor problem: this mechanism must be located the width of the panel away from the edge of the panel, i.e. any closer and it wouldn't be able to peel the layer off completely. Imagine, if you will, such a panel sitting before you with the film on it. Grab a corner of the film and attempt to remove it by pulling in a straight line, without l

            • by BigBlockMopar (191202) on Saturday February 28, 2004 @05:34PM (#8418884) Homepage

              A thread attached to a corner of every plastic sheet running diagonally to the opposite corner and an electric motor that activates when the sheet is dirty.
              Stack 10 sheets of this and voila, lifetime of the rover multiplied x10.

              Conceptually, this is a great idea, except for one problem:

              Every layer of $whatever you put on the panels attenuates some of the light striking the panels. The sunlight is also that much dimmer there (at the very least by the inverse square law of distance from the sun, if not also because of atmospheric conditions), so every single watt-hour those things can capture is critical.

              Of course, to compensate for the thin film layers, they could have made the solar panels bigger - but that adds launch weight... not to mention the bigger solar panels would make the whole thing more top heavy and likely to tip over due to wind or ground obstructions, meaning you'd want to add size and wheelbase to this thing, meaning you'd need more solar panels... Do we see a vicious circle yet? [grin]

              • Yea, well, but i suppose accumulated dust attenuates way more light than a few thin plastic sheets, no?

                And i know what i'm talkin' bout coz i park my car outside and never clean it ;)
                • by BigBlockMopar (191202) on Saturday February 28, 2004 @06:04PM (#8419095) Homepage

                  Yea, well, but i suppose accumulated dust attenuates way more light than a few thin plastic sheets, no?

                  Probably after a time, yeah. But the folks at NASA aren't stupid; I'm sure they would have come up with something like that - at least *after* Pathfinder if not before - and decided that cost/benefit analysis didn't make it worthwhile.

                  (ie. launch weight of the sheets and pulling mechanism, chances of binding and either obscuring a panel or getting caught in the wheels or instruments, chances of it catching the wind like a sail during sheet removal, reduced efficiency of cells over the long run rather than reduced efficiency of cells simply due to dust accumulation toward the end of the mission, etc.)

                  • by Yorrike (322502) on Saturday February 28, 2004 @07:22PM (#8419557) Homepage Journal
                    But the folks at NASA aren't stupid;

                    They're so incredibly smart, in fact, that they don't even need to convert metric measurements to the archaic system they insist on using.

                    Go NASA!

                    • by BigBlockMopar (191202) on Saturday February 28, 2004 @08:38PM (#8419888) Homepage

                      They're so incredibly smart, in fact, that they don't even need to convert metric measurements to the archaic system they insist on using.

                      Don't knock US/SAE measurements, there's a good reason they've stayed around.

                      For scientific analysis, without question, Metric rules.

                      But when you're actually building and working on things, most of the time a 10% tolerance is good enough. As a result, usually you can stick your thumb across something and say, "Yup, that's an inch - close enough". The base units are more intuitive, although admittedly the interconversion between units is a bitch - but conversions are more common in analysis than construction/maintenance.

                      My perspective here? Canada went Metric in 1976. I grew up in Metric. I went to school in Metric, fuelled up my cars in Metric, got a set of Metric wrenches when I was a kid, etc. Heck, you wanna know Metric inside and out? Try taking an engineering degree in Canada!

                      And yet, I know I'm 6'4" tall, 185lbs. I don't know in Metric.

                      Every time I work on a car, I want to know first, Metric or SAE? (And I don't mean the speedometer, they've all been Metric in Canada since 1976.) Not because I care which wrenches, sockets and feeler gauges I bring, but because I like working on SAE much more.

                      Why?

                      I've had more cars with Metric fasteners and specs than I have SAE, and yet, somehow, I can still just put my thumb across a bolt and know, "Hey, that's not 1/2", that's 7/16"!" Why can't I do that with Metric? I sure which I could, especially since I've got more experience with Metric.

              • by ozbird (127571) on Saturday February 28, 2004 @08:46PM (#8419915)
                So use roll of plastic like they use for the in-car cameras in Formula 1 etc. When the exposed section gets dirty, you just wind it off to the waste spool and clean plastic takes its place. Unlike tear-offs, there's only one layer of plastic which minimises light loss. If you had a method to clean the plastic, you could use a continous loop rather than a fixed-length spool.
          • You are kidding for sure.

            Say, a step motor and some mechanical jiggery-pokery ending with a stiff wire, a hook on its end, the layers would have tabs with holes in them to pull at.

            Or.. a glue between layers that deteriorates on contact with Martian athmosphere and so the layers will peel off after a fixed (based on chemistry) time.

            I mean, give me a break, those took less then 10 seconds to come up with and I am sure NASA engineers could have thought up much more effective methods.

            • Re:Solar problems (Score:3, Interesting)

              by torpor (458)
              Put the solar array on a vibrator, tilt the rover slightly, and give the solar panel array 15 minutes of shaking at some appropriate Hertz... oila, dust is shaken off.
              • Re:Solar problems (Score:5, Interesting)

                by IgnoramusMaximus (692000) on Saturday February 28, 2004 @05:28PM (#8418856)
                A vibrator? Might work although probably could be destructive...

                Hmm, after another 15 minutes of mental effort: a thin brush on an arm mounted to the side of the camera mast. You lower the (very thin and light single file brush) with a small step motor to the horizontal position and then you rotate the camera mast to create a sweeping motion on the panels. You could brush the 2 side panels that way, since if you planned for it, there would be no portruding gear to get in the way of the brush (all such gear would be back of the mast).

                And so on...

                I am really flabbergasted why there is absolutely no provision for any sort of cleaning (even a partial one) on the rovers. Its not like this wasnt expected. I smell some sort of hidden agenda in shortening the life of the rovers.

      • Re:Solar problems (Score:5, Interesting)

        by ModernViking (244510) on Saturday February 28, 2004 @05:11PM (#8418755)
        First, my credentials. I have worked on the field trials of the FIDO rover. It is the science test bed for the MER rovers that has been tested in various parts of the western United States over the past 6 years.

        There have been many ideas tested for the solar panels, including removable plastic coverings, wiper blades, etc. None of them have proven practical. The dust on Mars is extremely fine and electrostatically charged. It sticks to the panels , and every other surface, amazingly well. Figuring out a way to remove Martian dust from surfaces is a field that a lot of thought and experiment has gone into, without discovering any feasible solutions, so far.

        During the Pathfinder Mission in 1997, it was found that, by driving the rover over 'large' rocks (large for the rover), some of the larger dust can be shaken off. This is, as I've heard from members of the engineering team, something they intend to try with the MER rovers when needed. It doesn't make a huge improvement, on the order of a couple percent, but every little bit helps.

        • Re:Solar problems (Score:4, Insightful)

          by Flakeloaf (321975) on Saturday February 28, 2004 @05:22PM (#8418821) Homepage
          If the dust is electrostatically charged, what would be involved in covering the solar panels with a thin, transparent film or network of wires that is itself charged to repel this dust?
        • by Serious Simon (701084) on Saturday February 28, 2004 @05:30PM (#8418864)
          Once the robots find water, they could spray it on the solar panels to clean the dust off...
        • Re:Solar problems (Score:4, Interesting)

          by deglr6328 (150198) on Saturday February 28, 2004 @05:35PM (#8418889)
          Can you say more about why specifically the peel off transparent plastic idea was rejected(it seems to be the simplest, most effective, non-single point failure prone, most elegant solution I've seen so far)? I know all these speculative posts seem tedious and redundant, it's just that it seems like such a shame to allow the mission life of the rovers to be so severly shortened by such an apparently trivial problem.(it's just a little dust!! :o)
        • Re:Solar problems (Score:3, Insightful)

          by geekoid (135745)
          I would love to see notes from these kind of 'thought' groups. It is a big problem, and I think it should be put out into the public. Maybe a contest.

          If you think the people t NASA can't figure it out, then nobody can, you are just kidding yourself.
        • Re:Solar problems (Score:4, Insightful)

          by IgnoramusMaximus (692000) on Saturday February 28, 2004 @05:55PM (#8419024)
          None of them have proven practical

          I dont buy this for a second. Removal of fine, electro-statically dust, has been practiced on this planet for centuries if not millenia. There are entire industries [windex.com] based on this practice. I am convinced that it was one of those famous NASA managerial pissing contests that ensured no "feasible" or "practical" solution. Read: the companies which proposed the solutions were not part of the "in" crowd.

          • Re:Solar problems (Score:5, Insightful)

            by Dun Malg (230075) on Saturday February 28, 2004 @07:20PM (#8419547) Homepage
            I dont buy this for a second. Removal of fine, electro-statically dust, has been practiced on this planet for centuries if not millenia. There are entire industries[windex.com] based on this practice. I am convinced that it was one of those famous NASA managerial pissing contests that ensured no "feasible" or "practical" solution. Read: the companies which proposed the solutions were not part of the "in" crowd.

            The key difference you're missing is, in your own words, "on this planet". The fact that the rovers are on mars has two important effects. First, the atmospheric composition, weather conditions, and the nature of the martian dust itself render common dust abatement methods here on earth ineffective. The most common, spraying liquid and wiping, is totally out of the question when the temperature is -20 to -80 degrees C. Second, the inaccessability of a rover on mars means that complex mechanical "wiping" solutions are out of the question-- there's no one there to smack the side of the unit when a cam arm gets stuck, or replace a solar panel when a wiper blade gouges it with a sharp pebble.
            If you're so sure there's an easy solution, let's hear it. Your bizarre conspiracy theory makes no sense.

        • electrostatic dust (Score:5, Interesting)

          by dpilot (134227) on Saturday February 28, 2004 @06:40PM (#8419321) Homepage Journal
          Arthur C. Clarke wrote a story reminiscent of this, set on the moon. Two explorers in a dusty area, and some of the dust sticks to their faceplates. Wiping the dust off builds electrostatic charge, attracting more dust, so they're soon blind.

          ***SPOILER ALERT*** (and suggestion)

          Since rubbing causes static electicity, they rub their faceplates together. One charges one polarity, the other the opposite. So one faceplate comes out even dustier, the other clean. The explorer with the clean faceplate can lead the other back to the vehicle.

          Actually I always though static electricity came from rubbing dissimilar materials, so I wouldn't expect rubbing two identical-material faceplates to do squat. But there may be a lesson here. If the primary problem is really electrostatic, might there be some sort of electrostatic solution? (on future rovers) The most extreme would be an ion-wind generator with the 'benign' (dustwise) polarity attached to the panel. Another might be a charged wiper blade. I'm sure there could be other simpler electrostatic-based solutions.
        • Would high frequency vibrations work? When I worked in Canada, there used to be these beetles which be attract by the light from my halogen lamp and try and bury themselves into my pot plants (if they didn't fry themselves first).

          Being particularly curious, I dug a couple out of the soil. Being covered in dust, the first thing they would do is make a loud buzzing noise to warm up (and which would shake off the dust) and then open their wing case and take off.

          Would this method work with solar panels?
        • Re:Solar problems (Score:4, Interesting)

          by mnmn (145599) on Sunday February 29, 2004 @03:03AM (#8421439) Homepage
          Here are some ideas I'm sure have been considered:

          (1) Vibration.... the panels are lifted sideways and a motor at the top vibrates them for a few minutes. This will cost(1) the vibration motor (2) the lifting motor (3) lifting arm and hinges.

          (2) Clapping two solar panels together.

          (3) Compressed air. This is my fav. A small cylinder onboard could blow air across the panels about 10 times... increasing the life of the rovers 10 times. If theres enough gas in the atmosphere, replace the cylinder with a compressor. Its mechanically easy, less risk, and with a tiny compressor will add just a tiny bit of weight.

          (4) Wiper blades. The blades will have feathers on them like a feather duster.

          (5) Rotating panels. The panels would be disc-shaped and are rotated real fast like a CD to shake off the dust.

          (6) Flippin panels. Turn the panels upside down for a little while. Optionally, jerk them.

          (7) Roller film. Unlike camera film, one loop of film covers the panel and two axels at the panel ends loops the film around. Small brushes at one end will keep cleaning the film.

          (8) Driving into rocks. The rover can tilt its panel forward facing and drive into a large rock with a bumper. That way the martians wouldnt think much of our intelligence and cancel the invasion.

          (9) Tiny micro-rovers built by MIT undergrads to wander over the panels cleaning it. The micro-rovers will themselves have connectors to recharge. I'm thinking 2mm^2. Tricycle-shaped with a trailing brush.

          (10) Drive over a high dune just before losing power. That way when theres a wind storm, enough dust will be blown away to allow the rover to communicate with the satellite. Hopefully, most of the dust will be blown away.

          Some of the above ideas were taken from other posters. I believe they could have been used to build a rover that could in theory work forever.
      • Re:Solar problems (Score:3, Interesting)

        by CdBee (742846)
        Why not just use a high frequency transducer to clean the surface of the panels?

        Tilting and vibrating them might, possibly, shake some of the dust off?. Obviously this has to be balanced against the wear caused by the vibration so it may not be possible...
    • Re:Solar problems (Score:4, Interesting)

      by hottoh (540941) on Saturday February 28, 2004 @05:05PM (#8418709)
      I understood Nasa to say 'wiper blades' would not be effective due to the nature of the fine dust chemically sticking to the surface of the solar cells. Mechanical sweeping does not solve the real problem of the dust sticking to the solar panel.

      Just a guess based on Nasa commentary is the batteries will fail before the solar panels fail to charge them.
    • Damn it! Rudy Giuliani made it to Mars first and
      got rid of all their squeegee guys!
  • ACPI (Score:4, Funny)

    by compbrain (625174) on Saturday February 28, 2004 @04:44PM (#8418571) Homepage Journal
    "The hack works by reducing the power supply to a poorly functioning switch."
    You know, they could just tell the rover to use its ACPI functionality and go into standby and spin down its hard disks....
  • Fan (Score:4, Interesting)

    by RetroGeek (206522) on Saturday February 28, 2004 @04:45PM (#8418578) Homepage
    Is there some reason why these rovers do not have a fan to blow away the accumutating dust on the solar panels?

    The weight penalty should be offset by being able to work longer.

    Or is the dust sticky? Maybe something akin to a wiper?
    • Re:Fan (Score:4, Interesting)

      by goon america (536413) on Saturday February 28, 2004 @04:54PM (#8418647) Homepage Journal
      Doesn't one of their robot arms have a brush device for brushing off rocks? Couldn't they use that?
      • Re:Fan (Score:5, Informative)

        by RetroGeek (206522) on Saturday February 28, 2004 @04:57PM (#8418659) Homepage
        Doesn't one of their robot arms have a brush device for brushing off rocks?

        The ONE robot arm cannot articulate to a position to reach the panels (it is mounted underneath). Also, the brush is made of wire. Not something you would want rubbing against a solar panel.
      • RAT is short for "Rock Abrasion Tool", meant to remove the upper layer of a very hard rock.

        In the same way you'd not be keen to use a RAT to brush your teeth, you probably would not wish to use the RAT to clean a transparent surface of a solar panel. In fact I think you may have just given some poor engineer at NASA a heart attack just by suggesting the RAT come near the solar panels!
    • Re:Fan (Score:2, Insightful)

      by deglr6328 (150198)
      a fan would be overly complicated and would draw too much extra power at 1% of Earth's air pressure. Why not just add peel away layers (like a cleanroom tacky [tps-online.com] mat) of transparent plastic to the panels? A tiny motor would be enough to reveal a new layer now and then. It's hard to believe they didn't try to think of something like this or simply didn't care about the dust problem.
    • Re:Fan (Score:3, Informative)

      by DynaSoar (714234) *
      RetroGeek (206522) sez: "Is there some reason why these rovers do not have a fan to blow away the accumutating dust on the solar panels?"

      Lack of air mass. A fan on Mars would be only 1% the efficiency of the same fan on Earth, because there's that much less air. Plus then you're using more power and using up the batteries, to not much effect.

      I would have suggested an electrostatic charger, like the old Diskwasher Zerostat, for removing the charge from vinyl LPs, making them easier to clean.
    • Re:Fan (Score:3, Interesting)

      by frdmfghtr (603968)
      My guess is that the thin atmosphere would prevent any sort of blowing as such...the atmosphere is about a tenth of what it is on earth, so you would need a pretty big fam to get anywhere near the pressure needed to blow the dust clinging to the panels away.

      Besides, as has been pointed out, any solution adds power requirements, weight, and complexity/points of failure. Does the extra power provided by clean solar panels outweight the added risk of equipment failure?
  • You would think they would have installed some mechanism to clean the dust off.
  • by nicnak (727633) on Saturday February 28, 2004 @04:50PM (#8418611)
    The dust problem is just indicitave of how difficult it is to plan such a complex mission like going to Mars. Until we do this a few more times and figure out a few more things, a manned mission will have to wait.
    • by Gossy (130782) on Saturday February 28, 2004 @05:07PM (#8418721)
      Um, I seem to recall they knew about dust problems well before they launched. This isn't something that has surprised the engineers. I remember that was the main reason they said they were planning for a 90 day mission, since beyond that point the cells wouldn't charge enough due to the dust.

      I've also seen on SpaceFlight Now reports that projections show they will be probably be able to run both rovers well beyond the initially planned 90 days, so they're looking into plans for extended missions now.

      However, like others on the thread have wondered, why not devise something to remove the dust? I'm sure there must be a good reason why they didn't do something - I can't imagine the NASA engineers simply didn't think about this.
    • if we send men to Mars, hopefully they are wise enuff to get out of the rover (in space suits) and clean the solar panels. ;)
  • by blamanj (253811) on Saturday February 28, 2004 @04:52PM (#8418632)
    A nice photo [nasa.gov] from the Cassini mission.
  • Seasonal changes (Score:5, Interesting)

    by Dan East (318230) on Saturday February 28, 2004 @04:54PM (#8418639) Homepage Journal
    The blurb fails to mention that seasonal changes on mars are resulting in less sunlight per sol. That is one of the main power issues.

    Dan East
  • by r.jimenezz (737542) <rjimenezh@nOSpam.gmail.com> on Saturday February 28, 2004 @05:14PM (#8418768)
    ...to have the dust wiped off the rover's solar panels, it has many disadvantages. It has been discussed widely here, even by rocket scientists. In short, it is extremely difficult to come up with a "cost-effective" (from several viewpoints) mechanism. An interesting fact is that the cost of operating the entire mission is around US$ 3m a day, and that must also be considered when determining how long these wonderful bots rover through Mars unveiling its mysteries.
    • An interesting fact is that the cost of operating the entire mission is around US$ 3m a day, and that must also be considered when determining how long these wonderful bots rover through Mars unveiling its mysteries.

      That is a good fact. But from my viewpoint the major cost has been the mission failures. All that money spent when a probe goes up in smoke is just completely gone with absolutely no return. It seems to me that 90% of the problem is getting the probe simply to have a successful landing. Since
    • by grozzie2 (698656) on Sunday February 29, 2004 @05:07AM (#8421675)
      An interesting fact is that the cost of operating the entire mission is around US$ 3m a day,

      There are 2 types of cost involved in this daily figure, those that are 'out of pocket' and those that are 'just accounting'. Take for example, the DSN time used to retrieve data from the rovers. Yes, it's very expensive I'm sure, those deep space monitoring stations cannot be cheap to build and operate. Every hour they spend pointed at mars collecting data from the MER vehicles is surely tracked, and cost accounted to the MER program, and rightfully so. BUT, it's not like they wouldn't cost anything if they were not pointed at the mars probes, the actual cost of operating the DSN system is for all practical purposes a known and fixed cost, and it's gonna be paid, no matter where they are pointed. This is why I'd call that portion of the daily cost 'just accounting', because the taxpayer is going to foot the bill for the deep space network, regardless of where it's pointed. But, when it's pointed at mars, the mars programs are being accounted as the 'cost', and rightfully so.

      While the rovers are on active surface mission, there are a lot of extra people hanging around jpl, and i'm sure most of them are 'rather expensive' to keep on hand. this type of expense is 'out of pocket', it's an expense that wouldn't be happening if the rovers were not on surface mission. My own guess offhand is that the 3 million a day is probably half and half, one half true 'out of pocket' expenses, and the other half just accounting for equipment/personnel that would be on hand anyways, but are currently involved in the MER program. For the sake of easy math tho, I'm gonna suggest 1 mill is 'accounting' and 2 mill is 'real cost'.

      Now take a look at the overall value proposition. the entire program is running in the 850 million range, and it's targetted for 2 rovers on surface, for 90 days each. That's 180 science days for a total cost of 850 million, or 4.72 million per active rover science day, as per mission parameters. this was the value proposition of the original mission, and the mission(s) were launched on this basis.

      Now that surface operations are in progress, the daily burn rate is 3 million, for 2 rovers on surface. If a million of that is stuff like accounting for dsn time, then 2 million is the actual 'out of pocket' expense, or approximately 1 million per rover science day. this is 21% of the projected overall cost per day of science returned on the original budget.

      The up front cost of placing the equipment on the surface of mars has been absorbed, and is planned to amortize over the first 90 days on surface. After 90 days, it becomes a simple value proposition. The 'real cost' of maintaining full operations earthside is 21% of the original budget. In terms of the 'accounting costs' for things like the dsn time, it's the same type of value proposition. The dsn network WILL be kept busy, it's simply a case of determining where there is more value. The 70 meter dish can point out at voyageur and get engineering data from the deep space probe (which will still be there in another 2 months), or it can point at mars, and take advantage of the 'limited time offer' of recieving martian data at 79% discount off the 'full retail' price that was paid for the first 90 days of surface time.

      This is a large project, with lots of accounting involved, and surely there's more than its fair share of 'pork' buried in the 850 million price tag. BUT, it's real right now, and the real cost of retrieving a day of data from a single rover is in the range of $1 million. Considering the 'full retail' price for that runs 4.72 million after you amortize in all the launch costs etc, this is one time when a significant budget overrun due to 'extended surface time' is an absolute bargain.

      This is kind of a double edged sword though. A design life of 90 days means there is budget for 90 days of operation. An overrun of 90 days on operational time represents a huge value proposition for

  • by thedillybar (677116) on Saturday February 28, 2004 @05:15PM (#8418770)
    Every "feature" you add to this thing has its tradeoffs.

    1. It's going to weight more.
    2. It's another potential failure.
    3. IF it fails, it can cause other things to fail (say, for example, a switch sticks ON and it drains the battery)

    Not installing a wiper or other device to clear the solar panel wasn't an oversight. They made a (probably) well-informed decision not to install such a device. I think the progress so far is remarkable and should be commended. Hopefully they've learned a lot and can make improvements for the next mission.

    Hindsight is always 20/20...

  • The Martian Dust (Score:5, Interesting)

    by Chris Tucker (302549) on Saturday February 28, 2004 @05:18PM (#8418791) Homepage
    The big problem is that the dust is so fine, it'd be very difficult to wipe it off with anything akin to a windshield wiper. You might remove the dust, but the grit would scratch the glass, eventually causing enough opacity that the panels would eventually be rendered useless.

    One thought I had was to gradually apply a charge to the solar panels and then suddenly apply an opposite charge, causing the dust to be repelled from the surface, to be carried away by the Martian winds.

    I've no idea if it would actually work or not, but it seemed an elegant solution that didn't require any moving parts.
    • Re:The Martian Dust (Score:4, Interesting)

      by Scorillo47 (752445) on Saturday February 28, 2004 @05:53PM (#8418999)
      >>> The big problem is that the dust is so fine, it'd be very difficult to wipe it off with anything akin to a windshield wiper. You might remove the dust, but the grit would scratch the glass, eventually causing enough opacity that the panels would eventually be rendered useless.

      Probably using a vaccum would not damage the glass. Although this approach also adds more complexity...

      >>> One thought I had was to gradually apply a charge to the solar panels and then suddenly apply an opposite charge, causing the dust to be repelled from the surface, to be carried away by the Martian winds.

      Unfortunately this will not work since the electrical charge is not uniformy applied in only one direction on the surface glass. The small irregularities of the surface will cause a variation in the electrical distribution over time - for example a small peak in the glass might be more positively charged compared with inner of a nearly-located scratch. The same thing happens on some dust particles - due to their free movement in the air, their electrical distribution will end up non-uniform as well. So they will end up attracting as magnets - the small peak will attract particles on their negative-charged part, and the scratch will do the same on positively-charged surfaces. Now, since all these materials are good electrical insulators, the non-uniform distribution will stick on for a long time.

      Probably what would help is to use a blower that would wipe off the dust with martian air. The blown air needs to be ionized to prevent more electrostatic charge to add up by just blowing. The ionized air will have a weak electrical conductivity which will tend to "shortcut" the charged areas. Now, since the martian air is mostly CO2 this pre-ionization process shouldn't require too high voltages - the energy consumption would be pretty low...

    • One thought I had was to gradually apply a charge to the solar panels and then suddenly apply an opposite charge, causing the dust to be repelled from the surface, to be carried away by the Martian winds.

      Degauss the solar panels? Brilliant!

      ~UP
    • Re:The Martian Dust (Score:3, Interesting)

      by Anonymous Coward
      The sad problem is that solar panels aren't necessary at all. A little nuclear reactor and you're off and running for as long as you want. Not very PC tho.
  • by Crypto Gnome (651401) on Saturday February 28, 2004 @05:20PM (#8418805) Homepage Journal
    Opportunity has photographed a blue martian sunset

    It just plain makes sense, when you think about it.
    • Earth
      • Blue Sky
      • Red Sunset
    • Mars
      • Red Sky
      • Blue Sunset
  • by Paddyish (612430) on Saturday February 28, 2004 @05:21PM (#8418814)
    I have a bunch of questions about this stuff.

    Why did NASA stray from 'nuclear' batteries, like they've used with the Pioneer, Galileo, Voyager and Cassini missions? Those could power a rover for years.

    And what's stopping them from making a way to keep the panels clear? This is what contributed to the end of the Pathfinder mission...What is it about solutions to this problem that make them so difficult to implement?

    Wipers add an extra mechanical system to worry about, but what about static fields? Maybe there could be a way to attract the dust to a specific area while keep the the panels clear?

    • by vbdrummer0 (736163) on Saturday February 28, 2004 @06:01PM (#8419069)
      One suspects that NASA decided to go solar because of the potential disaster to be had if there was a 'mishap' during launch and radioactive material went everywhere in the upper atmosphere. Public protest against putting nuclear fuel on top of a controlled bomb grew steadily over the years, to the point that, if I recall correctly, Cassini hardly got off the ground due to some people protesting it. Probably, there wouldn't be much of a problem, but better safe than sorry (especially when you're funded by taxpayers).

      And I'll give the NASA geeks the benefit of the doubt that if there were a reliable and cost-effective wy of cleaning the solar panels, they would have implemented it long ago.

    • by FrostedWheat (172733) on Saturday February 28, 2004 @06:04PM (#8419091)
      Why did NASA stray from 'nuclear' batteries, like they've used with the Pioneer, Galileo, Voyager and Cassini missions? Those could power a rover for years.

      Most likely because the batteries would out-last the rover itself. It's a complex machine in a hostile environment- something will fairly soon. The solar panels will probably still be operating well after the rovers themselves have failed.
    • by hcg50a (690062) on Saturday February 28, 2004 @06:24PM (#8419221) Journal
      Why did NASA stray from 'nuclear' batteries, like they've used with the Pioneer, Galileo, Voyager and Cassini missions?
      First of all, those are all non-landing missions to the outer solar system (and beyond).

      This mission is a landing mission in the inner solar system, where the sun is bright enough to power the landers.

      Second, the use of radioelectric power generators is risky, dangerous and expensive. If there's a less risky, less dangerous and less expensive option, NASA will gladly take it.

    • by cmholm (69081) <.cmholm. .at. .mauiholm.org.> on Saturday February 28, 2004 @08:06PM (#8419762) Homepage Journal
      Some of you may recall that the Viking landers used radioisotope thermoelectric generators (RTG's), the "warm brick" another poster referred to. The landers remained active for up to six years, Viking 1 having been disabled by a boo-boo from mission control. They didn't have to worry much about dust accumulation, and Viking 2 landed at 48deg North, 'way north of the tropical band the MER planners were limited to by solar panels.

      So why nukes for Viking, and none for MER A & B?

      1) Viking had money. Sure, NASA was getting into a budget hurt locker by the time the missions made it to Mars in '76, but the money was there when it was needed during the planning and construction. The landers got the kitchen sink, and the biggest Titan II launchers then avaiable to get 'em going. By contrast, the MER team had to make sure their package was not much heavier and absolutely no bigger than Pathfinder. The planetary missions are bastard stepchildren to a NASA which is mandated to keep the Space Shuttle and ISS going on an inadequate budget, even if it all went to the manned space program.

      2) Three Mile Island, Chernobyl. Hadn't happened yet, so the no nukes crowd was still the wacko fringe during Viking. Compare to the fuss made over Cassini before launch and while making a gravity-assist Earth flyby. "200,000 deaths!" "Dump it in the Sun!" In general, people have mellowed out a bit, but the PR angle makes a good excuse when one doesn't have the money to gold-plate a mission, anyway.

  • by t0qer (230538) on Saturday February 28, 2004 @05:26PM (#8418847) Homepage Journal
    Use a Vibrator! No Really!

    I've been reading all the other posts, Every idea from peelable plastic sheets to fans..

    Just attatch a vibrating motor to the underside of the solar panels. When it's time for them to get clean, just raise them to a 90 degree angle, turn on the "orgasmotron vibrating motors" and shake the dust off?

    Maybe I watch too much pr0n, but I'm sure that would work for the heavier dust. Especially since there was an earlier comment on how the engineers purposefully drive these things over rocks to shake off the larger dust particles.

    One more thing, movable solar panels can track the sun, and give better light collecting efficiency than ones that just sit there stationary.

    --toq
  • by Papa Legba (192550) on Saturday February 28, 2004 @05:40PM (#8418916)
    I suggest a solar panel Zamboni! If for no other reason that Zambonis are cool and a space Zamboni would be a magnitude cooler. Imagine the great PR if NASA could send back shots of there Zamboni working on another planet.

  • Sunset (Score:4, Insightful)

    by Lord_Dweomer (648696) on Saturday February 28, 2004 @05:41PM (#8418920) Homepage
    So I'm curious. Lets say we colonized Mars. Because of all the coloring issues surrounding the Martian photographs, could someone please clarify whether we would actually see a blue sky when the sun set? Or is that just some optical properties of the camera?

    I have to say though, despite being an extremely short video clip, it is one of the most awe inspiring things I've seen in a while. Think about it. We just viewed a sunset ON ANOTHER PLANET. I can just imagine an art gallery featuring nothing but pictures of sunsets on other planets. As much as I love our planet Earth, I hope the day comes when I'll be able to stand on Mars and watch this for myself. The beauty of the universe is infinite, but every now and then a little piece of that beauty finds its way back to Earth, and we experience this beauty, and smile a little, not quite realizing the magnitude of what has just occured.

    • Re:Sunset (Score:3, Interesting)

      by FrostedWheat (172733)
      Because of all the coloring issues surrounding the Martian photographs, could someone please clarify whether we would actually see a blue sky when the sun set?

      The sky would be red as normal, but sometimes there would be a halo of blue sky surrounding the sun. Only sometimes because it depends on the amount of dust in the air. The Pathfinder mission saw sunsets with and without the halo. The halo may also happen during the daytime. There have been no colour pictures of the sun when it's high in the Mars s
  • by hcg50a (690062) on Saturday February 28, 2004 @05:55PM (#8419028) Journal
    "In other news, the rovers are beginning to experience power supply problems due to the accumulation of dust on their solar panels"

    This makes things sound worse than they actually are. They are not beginning to experience power supply problems -- they are simply getting less power than they were when it first landed, and they are taking some steps to operate more efficiently.

    From SpaceFlightNow, in the report for THURSDAY, FEBRUARY 26, 2004 2215 GMT (5:15 p.m. EST) [spaceflightnow.com]:

    "The amount of power Opportunity is able to generate continues to dwindle due to the decreasing amount of sunlight (energy) reaching the solar panels during the Martian seasonal transition to winter."

    From the Reuters [reuters.com] report:

    "NASA's two robotic rovers on Mars have begun scaling back their working hours as the approach of autumn on the Red Planet and dust on their solar panels slowly chokes off their power supplies, a NASA official said on Friday."

    What the NASA official (Richard Cook) actually said was: "The vehicle is continuing to perform fine but we are starting to modify our daily process to respond to the decreasing power."

    Both the dust accumulation and the decrease of sunlight were anticipated. The lifetime (designed to be 90 days) of each Rover is determined when the batteries can no longer be charged enough to survive the cold nights. Spirit is already 54 days into its 90-day "death sentence".

  • by dirt_puppy (740185) on Saturday February 28, 2004 @06:08PM (#8419125)
    You can't blow them off with opposite charge easily. These particles stick to the (non-conducting) surface probably because of Influence. If the surface would be conducting they wouldn't stick because they would get discharged. This is similar to the dust particles that adhere to CRT screens, just here its the screen thats charged (by constant electron bombardement) and the dust particles get influenced. The fact that the surface is non-conducting will also hinder you bringing any kind of charge to it. Another problem is that the charge might be randomly generated and so half positive and half negative, so you could only blow off half of the dust. There is a possibility of making transparent surfaces conducting (coating them with metal films), but this reduces transparency quite a bit, and I suppose the mechanical properties of a metal film are far inferior to whatever they used (you want this surface to be hard).
  • by rodney dill (631059) on Saturday February 28, 2004 @06:36PM (#8419295) Journal
    The APOD [nasa.gov] site had this picture of a "named" rock a couple of days ago.
  • by Katz_is_a_moron (197780) on Saturday February 28, 2004 @07:02PM (#8419448)
    Ok, hear me out.

    Cost aside, there most likely is a way to greatly extend the life of a rover.

    From the noises NASA has been making, there will be a series of unmanned missions to Mars before an attempt to send humans will be made (I don't necessarily agree with the premise of sending humans to Mars).

    NASA has said the limiting factor is power, because of the dust accumulation on the solar panels.

    Let's say that the cost of implementing a way to eliminate the dust doubled the cost of the mission (probably would be less). If dust were eliminated, then the rovers could operate until the batteries could not longer hold a sufficient charge to do science.

    What I'm getting at here is politics. A solution could be engineered to greatly extend the life of the rovers. But that would result in a reduced number of missions and *less funding*.

    Ok, I've removed my tinfoil hat. Comments?
  • by madpierre (690297) on Saturday February 28, 2004 @07:04PM (#8419463) Homepage Journal
    it's blue because of the optical scattering properties of dust in
    the martian atmosphere


    That's Scullys Xplanation.
    Mulder says different.

    Or it's because NASA's mission faking division forgot to photoshop the
    images before releasing em. ;)
  • by RevAaron (125240) <revaaron.hotmail@com> on Saturday February 28, 2004 @07:44PM (#8419659) Homepage
    It's called fines not dust, you insensitive clod!

    That's like calling dust gravel, jeeze.

    (with apologies to KSR's Red Mars)
  • by confused philosopher (666299) on Saturday February 28, 2004 @07:44PM (#8419660) Homepage Journal
    On Soviet Mars, the Pink sunsets are BLUE!

  • by Dominic_Mazzoni (125164) * on Saturday February 28, 2004 @09:22PM (#8420126) Homepage
    A lot of people are discussing ideas to remove dust from solar panels. Something people are forgetting is that there's a downside to having the mission last longer than originally expected: it costs more. JPL designed the rovers to last about 90 days, and NASA gave them enough money to pay the hundreds of engineers and scientists it takes to operate the rovers for 90 days each. They of course have the option of extending the mission for longer than 90 days, but the money to pay for that extension will come right out of NASA's Mars program, which means less money for future Mars missions (including Mars Reconaissance Orbiter 2005, which is already well under way and needs every penny it can get).
  • What? (Score:4, Informative)

    by Anonymous Coward on Saturday February 28, 2004 @09:57PM (#8420299)
    I attended a seminar last week with David Des Marais of NASA Ames reserch center. He noted that, while the panels were covered with dust, the rovers were still maintaining greater than peak power. He specifically stated that the rovers were shunting power because they couldn't store anymore. They suspect that the rovers will far outlive their contracted period.
  • by forgetful (725420) on Sunday February 29, 2004 @02:11AM (#8421321)
    Does anybody have a link to Mars Rover science-in-progress? We are getting all sorts of operations/engineering reports and neat photos, but almost no science reports. What have the spectrometers found? Does the rock chemistry correspond to known minerals on earth or is it new? What ever happened with the briny mud speculations a few days back? I suppose there is a methodical plan to analyze and release papers, but it sure would be fun to at least know the basic composition of those sphericles for coffee break discussion.
  • by billatq (544019) on Sunday February 29, 2004 @02:27AM (#8421353)

    So I just happened to be lucky enough to get front row seats (I work as a sysadmin in the physics department here) to a talk by one of the people on the JPL team that works on the lander, and he mentioned this earlier. It's a bit more than a little hack to the software because it involves changing out the operating system and turning the rover completely off during the night to avoid power drain. What the fellow talking about it mentioned was that there is the possibility that the rover wont actually turn back on after the update, leaving a $400 million piece of junk on the surface of mars.

    The reason for the update is needed because there is a heater on the rover that defrosts the probe that allows them to take samples from the rocks and such--which wont turn off anymore. This might not be a problem except that it puts an excess power strain on the rover, meaning that its useful life is greatly diminished. So essentially this hack means turning everything off at night because they can't switch off just the heater.

  • by FrostedWheat (172733) on Sunday February 29, 2004 @07:58AM (#8422027)
    My goodness, not even Mars is beyond the reach of Disney [nasa.gov]!!

There are never any bugs you haven't found yet.

Working...