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Mars Rover Spirit Down a Wheel

riflemann writes "NASA is reporting that two years into its 90-day mission, Spirit has lost one wheel and is now running on five wheels, dragging the broken wheel. With this reduced mobiity, the rover still needs to make its way to a slope where it can catch enough sun over the Martian winter to keep it operating. 'Even though the rovers are well past their original design life, they still have plenty of capability to conduct outstanding science on Mars.', says project leader Dr. John Callas."

67 of 272 comments (clear)

  1. Tis but a scratch by Anonymous Coward · · Score: 5, Funny

    I've had worse.

    1. Re:Tis but a scratch by metricmusic · · Score: 5, Funny

      A scratch? Your wheel's off!

      We thank thee Lord, that in thy merc-

      --
      http://www.livejournal.com/users/metricmusic
    2. Re:Tis but a scratch by buswolley · · Score: 2, Funny

      Lets all bow our heads for a moment.... for the loss of the sixth wheel.

      --

      A Good Troll is better than a Bad Human.

  2. Not so surprising by Reverend528 · · Score: 2, Funny

    That's what happens when you only test the wheels for 9 days.

    1. Re:Not so surprising by slightlyspacey · · Score: 5, Insightful

      What do you expect? The rover has lasted *8* times longer than design. That's the equivalent of driving 400,00 miles on tires rated for 50,000 miles. It's a heck of an accomplishment and I can only applaud the terrific job the design engineers and builders did.

    2. Re:Not so surprising by Chowderbags · · Score: 2, Funny

      It might even be the equivaltent of driving 400,000 miles on those tires too!

    3. Re:Not so surprising by slightlyspacey · · Score: 2, Funny

      Hey, it's still within an order of magnitude of the right answer and I didn't confuse English with Metric measurments :)

  3. Re:Great... by Anonymous Coward · · Score: 2, Funny

    Dumbass. 5 != 3

  4. Still a tossup - Rovers dead before Vista released by SpaceLifeForm · · Score: 4, Funny

    I still believe both rovers will be alive
    when and if Vista is ever released.

    --
    You are being MICROattacked, from various angles, in a SOFT manner.
  5. Re:Still a tossup - Rovers dead before Vista relea by therage96 · · Score: 3, Funny

    Aha, but will they still be functioning when Duke Nukem Forever gets released? I mean, 2514AD is a long ways away!

  6. Re:Still a tossup - Rovers dead before Vista relea by GKThursday · · Score: 5, Funny

    I don't think their hardware meet Vista's specs.

  7. At first read, I get dissapointed by R2.0 · · Score: 5, Insightful

    Then I remember a story Spider Robinson told about a cheap digital watch that died on him. He was pretty pissed off, but then he remembered that:

    a) it was originall a Crackerjack prize or some other freebie.

    b) it was 5 years into it's projected one year battery life.

    At this point he gave it a solemn memorial service and kept it in a revered place (I think he may have buried it).

    Whenever they finally die, I hope that they find an honored place in whatever museum the future Mars colonists decide to set up.

    R2.0

    --
    "As God is my witness, I thought turkeys could fly." A. Carlson
    1. Re:At first read, I get dissapointed by partymonkey · · Score: 3, Interesting

      Maybe it's just me, but I doubt they spent all that money on the rovers for just 90 days of operation. I'd be willing to bet that they designed them to last 3-5 years. Also, they were probably just setting expectations *really* low, so if the rovers failed early then they still looked good in the public eye.

    2. Re:At first read, I get dissapointed by HoneyBunchesOfGoats · · Score: 2, Insightful

      Or, car manufacturers could decide that you'll assume "longer warranty == longer-lasting car," raise their warranty to 80,000 miles regardless of the fact that the car is crap, and bank on the fact that you'll want a new car within a couple years anyway.

    3. Re:At first read, I get dissapointed by livewire98801 · · Score: 5, Funny

      Scotty: 8 weeks, sir

      Kirk: Mr Scott I-

      Scotty: But you don't have 8 weeks, so I'll do it for you in 2

      Kirk: Mr Scott, have you always multiplied your repair estimates by a factor of four?

      Scotty: Of course, Admiral, how else can I keep my reputation as a Miracle Worker?

      Kirk: Your reputation is secure, Mr Scott.


      If I recall, this dialoge was in ST:3, but I'm not sure of that.

      --
      "He may be mad, but there's method in his madness. [...] It's what drives men mad, being methodical." G.K.Chesterton
    4. Re:At first read, I get dissapointed by Dominic_Mazzoni · · Score: 2, Informative

      That's partially true, but another important aspect of it is that if they had planned on a five-year mission up-front, the budget would have been several times larger - and in fact the project might never have been funded at all. So they decided on a mission length long enough to get some interesting science done, but short enough to look cheap.

      After 90 days, they went and asked for additional money. What's NASA going to do, stop running the rovers because they're over budget? Of course not. Unfortunately now they're eating into money that would have gone to other Mars missions. But it's still far more sensible to spend a dollar on the rovers already on Mars than on a future rover that may or may not make it to Mars.

  8. It's not "dragging" the sixth wheel by parc · · Score: 2, Informative

    It's more accurate to say that the wheel is free-spinning. It isn't contributing to drive power, but it's not drawing any current, either. It can still steer, so it's not off at some odd angle.

    Additionally, there's only been a couple days worth of data -- noone really knows why the motor stalled.

    1. Re:It's not "dragging" the sixth wheel by cmacb · · Score: 5, Informative
    2. Re:It's not "dragging" the sixth wheel by Tablizer · · Score: 5, Informative

      They stopped using the wheel about a year ago for a while because it was having problems as if the lubricant was wearing off, and it indeed did *not* free-spin when power was not sent to it. They simply dragged it around by running the rover backward. They found it easier to control the rover by dragging the bum wheel rather than by pushing it. They only used the wheel for close-up control when rocks were being targeted. Eventually it started working properly for a while, and now won't turn at all. It does not appear they have a "free spin" mode. Dragging is it.

      I beleive they have a video about the last time the wheel was left dragging. They did some test-bed simulations of an Earthly rover copy. Page down to the "Driving Uphill Backwards" portion, about half-way down the page:

      http://marsrovers.jpl.nasa.gov/gallery/video/spiri t01.html

    3. Re:It's not "dragging" the sixth wheel by Tablizer · · Score: 2, Interesting

      yeah this is a year old, what the hell, you suck slashdot

      Hold on, Tex. The older problem was that it drew too much current. It still worked and they used it for occasional tight maneuvering. Now it appears to be all-the-way gone. However, it went back to normal for a while before it completely failed. It is even possible the problems are not related.

      The speculation was that lubricant was not spreading around enough, creating friction, and that the problem went away because lubricant finally dripped into the right place. A sudden failure does not really match that hypothesis as one would expect the friction (power current needed) to slowly drift upward again before the failure. At this point nobody really knows what happened.

      Either way, the first problem was less severe and thought to have since gone away.

  9. Only lost 1 wheel? pfft by Anonymous Coward · · Score: 5, Funny

    If a dog can walk on two legs you better hope this thing keeps going, otherwise it's pretty embarassing.

    http://youtube.com/watch?v=OZqVvYkCe68

    1. Re:Only lost 1 wheel? pfft by archen · · Score: 5, Funny

      Actually I used to have a dog with two legs. I named him cigarette. Ever day I'd take him out for a drag.

      heh, sorry.. had to make the joke...

    2. Re:Only lost 1 wheel? pfft by Rob+Carr · · Score: 2, Interesting

      Our vet got a call for a dog involved in an accident. When the vet got there, she found a dog that had lost most of the front right and rear left legs to a crush injury. The dog was running around and was hard to catch. They expected the vet to put the dog down, but she wound up cleaning up the amputations and infections. The dog was given to a family. Last I heard, dog and family were doing fine, although if the dog gets out of the house without a leash, it is still hard to catch.

      --
      This sig seemed like a good idea at the time....
  10. C'mon ya pansy by Anonymous Coward · · Score: 5, Funny

    The NASA engineers always triumph!

    1. Re:C'mon ya pansy by Krakhan · · Score: 2, Funny

      *Rushes in* No one expects the Spanish Inquisition!

  11. exploration will continue by MoFoYa · · Score: 5, Insightful

    I think its great that the mars rovers lasted as long as they have. when you consider the failed mars mission attempts, spirit and opportunity are huge successes that have long outlasted their expected lifespan. The new mars orbiter "MRO" is sure to provide more information about the surface of mars, and possible landing sites for even more capable landers in the future. my question to /.ers is this: should we be focusing so much on mars or should we be looking toward other possible outposts/life harboring worlds like europa. and the new horizons mission to pluto - a waste of time, or an exciting new learning opportunity? personally, i doubt life will be found on mars. and i'm doubtfull any significant life will be found anywhere in our solar system. but, we are natural explorers who will continue to explore, even with a bum wheel.

    1. Re:exploration will continue by cashman73 · · Score: 2, Funny
      my question to /.ers is this: should we be focusing so much on mars or should we be looking toward other possible outposts/life harboring worlds like europa.

      Didn't HAL (or Dave Bowman, or whomever the aliens were) tell us, "ALL THESE WORLDS ARE YOURS EXCEPT EUROPA. ATTEMPT NO LANDINGS THERE."?

  12. Cold by MichaelSmith · · Score: 3, Interesting

    Its almost winter in the southern hemisphere of Mars. I wonder if there is a chance that a contact has contracted in the cold enough to break off power to this motor. Who knows? Spirit has been lucky before. Perhaps this wheel will start working again in the summer.

    Failing that I am available to fix the broken motor, assuming that NASA can provide transportation :)

    1. Re:Cold by HermanAB · · Score: 2, Funny

      Sure, they can provide transport - one way - and there is that little niggling problem with orbit insertion and parachute deployment that sometimes crop up... :)

      --
      Oh well, what the hell...
    2. Re:Cold by Prof.Phreak · · Score: 2, Funny

      Sure, they can provide transport - one way - and there is that little niggling problem with orbit insertion and parachute deployment that sometimes crop up... :)

      In other words, they'll use a large trebuchet to get you there (or somewhere... either way, it will be fun!)

      --

      "If anything can go wrong, it will." - Murphy

  13. Conversation I never Overheard by Black+Copter+Control · · Score: 5, Funny

    Martian1: It broke it's leg. I say we shoot it and put it out of it's misery.
    Martian2: nah. It seems to have such a drive for life.

    --
    OS Software is like love: The best way to make it grow is to give it away.
    1. Re:Conversation I never Overheard by Anonymous Coward · · Score: 5, Funny
      Martian3: How come neither of you knows how to use apostrophes correctly?

      /shoots martians 1 and 2

    2. Re:Conversation I never Overheard by bckrispi · · Score: 2, Funny

      Oh, you make me verrry angry. Verrry angry indeeeeed!!

      --
      Xenon, where's my money? -Borno
    3. Re:Conversation I never Overheard by Marce1 · · Score: 2, Funny

      Martian4: Proper Noun Police; Put the gun down and step away from the sentence!

      /Edges toward Martian3 with a capital M held out, still aiming

      --
      [ insert meme here ]
  14. 2 years into a 90 day mission... by HermanAB · · Score: 5, Funny

    Hmmm, typical NASA project, 21 months late and far over budget. :)

    --
    Oh well, what the hell...
  15. Late Breaking News: by iced_773 · · Score: 4, Funny

    A sense of triumph swept our fair red world today when reports came in that the Grand Army of the Council had damaged one of the robotic invaders from the evil blue planet. K'Breel, speaker for the Council of Elders, made the following comment:

    This was a great victory in our war with the evil blue planet. While we have only impaired the horrid machine's movement, we will continue to strike until it and its dreadful twin are pools of molten metal.

    When a journalist suggested that the terrible monstrosity had merely worn out one of its locomotive rotators, K'Breel had the traitor's gelsac mutilated immediately.

    Apologies to TripMaster Monkey.
  16. Shoulda got the AAA Extended Service Plan by slickwillie · · Score: 4, Funny

    100 mile free towing too!

  17. Failed brushes? by dougmc · · Score: 4, Interesting
    "It is not drawing any current at all," said JPL's Jacob Matijevic, rover engineering team chief. One possibility engineers are considering is that the motor's brushes, contacts that deliver power to the rotating part of the motor, have lost contact.
    Brushless motors are generally 1) more efficient and 2) longer lasting (with no brushes to wear out) and 3) more expensive (especially when you include the ESC, electronic speed control) than otherwise similar brushed motors. (But when you send something into space, who cares about an extra $1000 on motors?) I'm rather surprised that they didn't go brushless in something like this. Brushless motors are also cleaner, as there's no brushes to wear down over time. This is critical in zero gravity environments like orbit (nobody wants brush-dust floating around) and wouldn't be so important on Mars, but even so ... I wonder why they used brushed motors. Even if they things weren't supposed to last very long, you'd think brushless motors would be more efficient, giving them some extra power to work with, for not much extra money.

    (My experience with brushed and brushless motors comes from R/C planes, where a brushless motor is sometimes twice as powerful and 50% more efficient than a similarly sized brushed motor. Of course, a large part of this is that the brushed motor is dirt cheap, made cheaply in every way, and the brushless motors are of higher quality, but even so, even when comparing high quality stuff (and not cheap speed 400 can motors) the brushless are signifigantly better.)

    1. Re:Failed brushes? by HoneyBunchesOfGoats · · Score: 2, Insightful

      I have a hunch that the brushed motors NASA used in the rovers are probably a little bit more expensive and higher-quality than what you're used to dealing with on miniature airplanes. There are most likely some design issues we don't know about that made them use a brushed motor.

    2. Re:Failed brushes? by Anonymous Coward · · Score: 5, Interesting

      Actually, having recently heard a talk with people from JPL I can tell you why. They went with brushed motors because it was what had been previously used and was, therefore, seen as a safe option. For future robotic missions they plan on using brushless motors.

    3. Re:Failed brushes? by v1 · · Score: 4, Interesting

      Brushless motors are more complex, and require an array of active electronics inside them to produce the AC and modulating magnetic field they need to operate. Most brushless motors are lower torque than their brushed counterparts. (majority, I know there will be exceptions) Brushed motors are more mechanical in nature and suffer from the usual mechanical issues, but they are less prone to failure than brushless. Also, traveling through space and landing on a planet that may not have a protective magnetic field, active (transistor based) electronics must be carefully protected against emi that can disable or damage them.

      I'm sure they went brushed for a variety of very good reasons. The technology of brushless was available when the rovers were designed, and I can't imagine NASA not seriously considering them.

      --
      I work for the Department of Redundancy Department.
    4. Re:Failed brushes? by Tablizer · · Score: 2, Insightful

      While NASA is very proud to have exceeded expectations with the Rovers, I think this is mostly because their expectations of solar powered vehicles were so abominably low. Perhaps they will take things more seriously from now on.

      Their budget was for 90 working days. That is how the contracts stipulated payment. Further, the solar panels have been cleaned repeatedly by dust devils. Experience with the 2 Viking landers showed that dust builds up pretty quickly on probes and they understandably factored this into the design. The dust devil cleansing was a lucky accident. They had no certain landing areas picked out when the rovers were being designed, so they could not expect to rely on landing in whirl-windy areas, even if such could be identified from orbit. (It appears there are more dust devils near the equator than where the Vikings landed. However, there are probably also regional variations, based on the "criss-cross" patterns seen from orbit and created by dust devils.)

      In fact, it has been a while since Spirit has been cleaned by one, and that is one reason they have to rush to sun-facing slope. Future crafts that land in non-whirl-wind areas of Mars may face an early demise if they rely on solar (unless they bring their own cleaning systems).

      I believe Spirit had about 2 whirl-wind "cleaning sessions". Next year when the winds pick up it may have 4 or zero. It is the luck of the cards that determine it, and so far only during the summer. Thus, Spirit may have a sluggish spring.

      In short, I see no reason to bash Nasa's general approach. Sure, it would be nice to have a fat budget to include bells and whistles for extended missions, but the budget is the budget. Plus, they had a fairly short ramp-up time between approval and build. They had to use a lot of existing Sojourner technology almost as-is to reach the deadline.

    5. Re:Failed brushes? by dougmc · · Score: 2, Informative
      The rover uses maxon's motors which also are used in artificial hearts, surgical tools, and underwater robots
      Maxon makes lots of motors, both brushed and brushless. If you look at their web site, you'll notice that most of their new motors are brushless.

      As for the list of applications you gave, I'm guessing that new designs of these products use mostly brushless motors now, if only for the reason that they last longer and the brushes aren't ground down to dust over time.

      those aren't your mother's DC motors 8D
      My mother doesn't need a Rascal yet. In any event, I doubt these motors are that different from what use use down here on Earth. Sure, they're probably built better, with better materials and such, but the general design and layout is probably very similar.
    6. Re:Failed brushes? by dougmc · · Score: 4, Informative
      Brushless motors are more complex
      Actually, they're simpler, since there's no brushes. Generally the permanent magnets are on the shaft that rotates, and the electromagnets are on the part that doesn't, with three wires coming out (and possibly five more for a sensored model, but the sensorless models are more popular now.) Ignoring the older sensored models, the brushless motors are signifigantly simpler than brushed motors.
      and require an array of active electronics inside them to produce the AC and modulating magnetic field they need to operate.
      Actually, the electronics are generally outside the motor, in an ESC (electronic speed control), but I'll admit that it doesn't matter where they are. Brushed motors use an ESC as well to control the speed, so you've got some electronic parts either way. You're right that a brushless ESC is more complex than a brushed ESC, but the difference isn't really that signifigant.
      Most brushless motors are lower torque than their brushed counterparts. (majority, I know there will be exceptions)
      Torque is a function of motor design. It really has little to do with brushed or brushless, and you can certainly make high torque brushless motors if desired. If you need a motor with more torque but the same power (and less speed, since power = torque * speed) you either design an appropriate motor, or adjust your gear ratio so the amount of torque your motor does provide is appropriate for your use.
      Brushed motors are more mechanical in nature and suffer from the usual mechanical issues, but they are less prone to failure than brushless.
      And I disagree completely. Brushes wear out. (So do bearings and bushings, so it's a race to see which one wears out first, but in my experience, it's usually the brushes.) And for anything where you control the speed of the motor, you'll have an ESC (electronic bits) that can fail, but as a general rule of thumb, electronic bits are more reliable than mechanical bits.
      Also, traveling through space and landing on a planet that may not have a protective magnetic field, active (transistor based) electronics must be carefully protected against emi that can disable or damage them.
      Even the brushed motors will have ESCs on devices like the Mars Rovers (since the alternatives suck for a robot) and so either way you'll have active electronics to deal with. Also, the Mars rovers aren't operating in space -- the atmosphere (thin as it is) and magnetic field of Mars do provide considerable protection (compared to a satellite or something that is in space) against things like ionizing radiation.

      This stuff isn't rocket science. Even things like scooters, Segways and electric cars use similar technology.

      The technology of brushless was available when the rovers were designed, and I can't imagine NASA not seriously considering them.
      I'm guessing that the AC who posted in this thread was right on -- that NASA used brushed motors because they've used them in the past and they worked fine then, so they'll work fine now -- when you're spending billions of dollars on things that can't be repaired in the field, you tend to stick with what's tried and true rather than what's 15% more efficient but not quite so well tested. I suspect that future rovers will have brushless motors, however.
    7. Re:Failed brushes? by dougmc · · Score: 2, Interesting
      Second of all the, Mars' rovers spent considerable time in transit to Mars with no outside protection at all.
      As a general rule of thumb, ionizing radiation doesn't usually immediately destroy electronic components (at least those that we've hardened for space duty) when it hits it. The damage can accumulate over time, or it can cause a `glitch' changing a 0 to a 1 in a digital circuit (which can do nasty things like crash computers (which is taken care of by watchdog systems that initiate a reboot when needed)) but things don't generally just `stop working'.

      This page gives some good information on exactly what the effects are and what can be done about them.

      Third of all while there is some protection offered by Mars, it is still much worse than anything on Earth.
      I was wrong when I assumed that Mars had a substantial magnetic field -- it does not. But even so, the atmosphere, even being only 1% as thick as ours, would provide considerable protection. The Martian surface probably gets far less ionizing radiation than a satellite in Earth orbit would, for example.

      And don't forget that the Mars rovers are controlled by computers. Computers are far more vulnerable to ionizing radiation than other forms of electronics. And really, ESCs are pretty simple, being mostly just analog components. They should be relatively resistant to ionizing radiation -- far more so than the computer components that control them. So I don't think that's really a big issue -- just protect them half as well as you protect the computer parts, and you'll be just fine. And also don't forget that the Mars rovers already almost certainly have several ESCs ... it's not like using brushless motors would add ESCs where there were none before.

  18. Re:Great... by Anonymous Coward · · Score: 5, Funny

    My tricycle had training wheels.

  19. I'm still amazed.... by zappepcs · · Score: 2, Insightful

    This robot was supposed to last about 9 months... I think it has gone waaayyyy past the rated mileage for that wheel. The fact that it is free-wheeling and not a major hinderance is just a testament to how well it was actually designed. This 3x life-span thing is incredible if you take into account all of the challenges that the designers faced. I dabble in hobby robotics, and I can attest to the fact that designing a robot that does as well as it has done for as long as it has done, is a major accomplishment. Think about the warranty that you get on a new automobile... if it performed past its expected lifetime of usefulness to the tune of 300 percent, people would be driving vintage cars all over the place.... it is an amazing robot and planetary exploration vehicle!

    1. Re:I'm still amazed.... by zappepcs · · Score: 4, Insightful

      Those are very good points, but I think that most of the reason for the unexpected longevity of the mars rovers is that they expected dust from dust storms to critically hamper the solar panel operation. What was a surprise is that the wind quite effectively kept the solar panels clear of dust, giving a much longer lifetime. I don't think that the engineers expected to have to worry about the motors lasting 36 months or more since it was not expected. Mars has quite extreme temperature swings, so the engineering is probably worth what it cost to build the rovers. Mother nature is something that just can't always be anticipated, unless, of course, you anticipate problems due to mother nature. In that case, any positive turn of fate leaves you in the position of underestimating vehicle longevity.

      The temperatures, radiation, dust, vibration... these are very harsh environmental variables. It is just amazing that they are still running. I'm sure that NASA is still as amazed as we are, and pleased to be continuing the scientific research at what amounts to a budget bonanza.

      You are most probably right in thinking that what was learned this time around will be incorporated in the next planetary exploration vehicles, and a longer lifetime expectation will be part of that. In line with that, recent NASA un-manned missions have been incredibly successful. I look forward to more solar system exploration, and also to commercial exploration based on NASA work.

      Now that we know how to build robots to explore Mars, we can build them to explore other planets, and that ion engine thing is a Trekie's dream. The expectation bar is rising, and that is a good thing. The X-prize and similar efforts are creating huge scientific 'wealth' for all to use. Its all very cool.

  20. all alone in the cosmos by JTW · · Score: 3, Interesting

    The rovers are interesting critters.. not unlike their older sibling Pioneer 10.

    I guess we've given up on artificial intelligence, but I rather think what we altogether thought was a mind of information is actually a mind of situation and evolving spirit that simply exists in the moment. If that be true, even an Ant could have artificial intelligence.

    Its interesting we drive these things into the ground, or until they run out of power, or we loose interest.

    It may be lame, But I'd think it might be more interesting in the long run to upload a final survival program into these critters and turn them loose.. perhaps in the long run we'll come to those ideas and terms. Perhaps years from now when astronauts decide to land there they really will find martians!

    Of course if we have a nuclear or biological melt down, then perhaps they will out live us.

    There was a SciFi story long ago called NightFall.. it would make an interesting animated short or story to tell the story from the rovers perspective... and in the end they are given their freedom and continue to look up at the night to the twinkle in the sky where their makers live, and then.. they loose contact, perhaps they merely lost interest in their creations.. or perhaps the makers are no more, and they truly are all alone.. and as the cold surrounds and grips them they fold up their solar wings preparing for another martian winter and the rovers go to sleep.. perchance to dream.. of other worlds.

  21. The Truth... by Tatarize · · Score: 4, Funny

    They made Spirit and Opportunity do some battlebot stuff. And well, Spirit is a puss.

    --

    It is no longer uncommon to be uncommon.
  22. Even if it can't make it up the slope... by artifex2004 · · Score: 3, Interesting

    Why would the rover actually permanently die if it ran out of power?
    Surely when the Martian winter comes to an end, and the area it's in is flooded with sunlight again, the solar cells could still work, the battery could recharge, and it could wake up?

    Or did nobody think about a cold restart?

    1. Re:Even if it can't make it up the slope... by deong · · Score: 5, Informative

      It's not that simple. The rovers are full of fairly sophisticated sensor packages, most of which can't handle the extremely low temperatures on the Martian surface. They need the batteries to basically, well, run the heater.

      The principle investigator for the missions has written a book, "Roving Mars", that really is worth the read.

    2. Re:Even if it can't make it up the slope... by ScottMaxwell · · Score: 4, Informative
      It's not that simple. The rovers are full of fairly sophisticated sensor packages, most of which can't handle the extremely low temperatures on the Martian surface. They need the batteries to basically, well, run the heater.

      Bingo. Indeed, it's even worse than that: if you can't run the heaters, all of the electronics undergo more extreme thermal cycling. This causes components to contract, flex, break, etc. Several critical components -- e.g., the CPU -- have no redundancy; if one of those goes, the whole rover goes.

      This failure is the most dangerous thing to happen to Spirit since the flash anomaly on sol 18, when we effectively lost contact entirely for several days. Frustratingly, we're within sight of a safe haven -- only about a football field away -- but we might not be able to get there. Some people on the team think that if we have to drag a wheel, we can't climb the slopes we need to climb to make it to safety. I would just hate for Spirit to go this way; it would be like dying of thirst within sight of water, and she deserves better. (On the other hand, one thing I've learned is this: never bet against the rovers.)

      The principal investigator for the missions has written a book, "Roving Mars", that really is worth the read.

      Agreed! And since Steve's such a great guy, I'll linkify that. :-)

      Also looks like it's coming out in paperback soon.

      --

      ``Life results from the non-random survival of randomly varying replicators.'' -- Richard Dawkins
  23. Re:Still a tossup - Rovers dead before Vista relea by rspress · · Score: 3, Informative

    The computer in each Mars Exploration Rover runs with a 32-bit Rad 6000 microprocessor, a radiation-hardened version of the PowerPC chip. This chip is used in IBM's heavy duty computers and is the same family of chip in the pre-intel Macs, Xbox 360, GameCube and the Cell version will run the PlayStation 3.

    The chips are fairly cheap and have lightning fast floating point calculations via alti-vec. They are also very easy to program for.

    NASA claimed they would only work for 90 days due to the high iron content of martian soil. In 90 days the solar cells were supposed to be covered with magnetized iron dust and the cells would not get enough sun to charge them. That never happened. Considering the cold, dusty, unsheilded environment they are in it is amazing they have lasted over two years.

  24. Pfft, try just ONE leg... by ChePibe · · Score: 4, Funny

    This little guy seems to make it on his own just fine on one leg. Although, admittedly, he'll prob'bly never take him a wife.

  25. Pit Stop by SuperKendall · · Score: 4, Funny

    Hopefully at the next Pit Stop the guys that are wiping down the solar panels will also jack it up and change out the wheel.

    Ten seconds! Go!

    --
    "There is more worth loving than we have strength to love." - Brian Jay Stanley
  26. I am saddened... by rice_burners_suck · · Score: 4, Funny
    ...to hear that the rover has lost a wheel,
    though pain it does not feel.

    Now it limps along the Martian soil,
    alone in a great vastness of red sand and rocks.
    I hope it reaches the top of the slope,
    else alas for naught will it toil.
    For in that vast desert there's no telephone box.
    Nor much chance for hope.

    Like the injured lone explorer,
    Oh! What a horror!

    it will suffer its demise,
    Alone on that alien world,
    Its nearest neighbor far away,
    as no one hears its cries.
    The wrath of Mars is unfurled,
    And there alone will it lay.

  27. Tire tracks, not water by tilde_e · · Score: 5, Insightful

    It is so interesting that we leave tire tracks on other planets. They may be that the first signs of life we find, or that other beings find.

    Imagine the tension if we found ourselves face-to-face with a foreign martian rover!

    1. Re:Tire tracks, not water by Dr.+Eggman · · Score: 4, Informative

      Not quite. Martian weather is quite likly to blow away the tracks before anything found them.

      You can get your Martian weather forecast here: http://astro.sci.uop.edu/~harlow/weather/mars.html

      --
      Demented But Determined.
  28. PHB Response by Golias · · Score: 2, Funny

    It's remarkable how much longer these guys have still been alive even after they already completed their originally planned goals. Here's one thing that NASA did right.

    What are you talking about? Their projections were WRONG by an order of magnitude. They should all be fired for failing to predict the life-span of these rovers accurately.

    --

    Information wants to be anthropomorphized.

    1. Re:PHB Response by SEWilco · · Score: 2, Funny

      The cost of support operations for the rovers is way over budget.

  29. Re:Still a tossup - Rovers dead before Vista relea by yoprst · · Score: 2, Informative

    If memory serves me well (and it often doesn't), Rad 6000 is something like $600000

  30. One Wheel Dragging? by Derling+Whirvish · · Score: 3, Funny

    One wheel dragging huh? Must be that the Mars rovers are manufactured by the same company that make the shopping carts for Walmart.

  31. Re:Still a tossup - Rovers dead before Vista relea by Moridineas · · Score: 4, Informative

    Uhm, this gets informative? The Rad6000 chip runs at 20mhz according to wikipedia and 25mhz according to other sources. The chip is based on EARLY power cpu designs (think early/mid 1990s), and most definitely does NOT include any sort of altivec technology.

    No radiation hardened space suitable chips are "cheap." Expect to spend tens, if not hundreds of thousands of dollars per CPU.

    That's not to say it's not a great chip for what it does, but come on...

  32. Re:Still a tossup - Rovers dead before Vista relea by flyingsquid · · Score: 3, Funny
    To be fair the rovers were lucky to land in areas with lots of whirl-winds to clean them. If it was not for the whirl-winds the rovers would probably be paper-weights by now.

    Well, future rovers could carry around little Roombas to run around and vacuum off the top of their solar cells.

  33. Overtime? by DeadboltX · · Score: 3, Funny

    "NASA is reporting that two years into its 90-day mission"

    Talk about overtime, you think the rover gets time and a half now?

  34. Re:Still a tossup - Rovers dead before Vista relea by rspress · · Score: 2, Interesting

    Yep you are correct. Sorry I was confusing the RS6000 brand of IBM chips with the RAD 6000.

    I was also quoting NASA as for them being cheap. When the landers were on there way they said in interviews on TV that they were cheaper chips......looking at wiki it is hard to find many other RAD hardened chips.