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Mars Space Science

End of the Road For NASA's Mars Rover? 181

Posted by CmdrTaco
from the hello-up-there dept.
An anonymous reader writes "NASA celebrated Mars rover Spirit's bountiful, six-year stint on the red planet on Sunday – way longer than its forecast three-month mission. But it all may soon come to an end, stuck as it is in Martian sand."
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End of the Road For NASA's Mars Rover?

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  • by Chris Burke (6130) on Monday January 04, 2010 @12:55PM (#30642506) Homepage

    Does it need continuous power to stay capable of operating?

    Yes. It requires some nominal amount of power for heating to avoid freezing and damaging components. This is what happened to the Phoenix lander (as anticipated in that case). With the panels covered in dust, plus the additional cold and lack of sunlight during the winter, Spirit is unlikely to survive the winter unless something changes.

  • All is not lost (Score:2, Informative)

    by Anonymous Coward on Monday January 04, 2010 @12:58PM (#30642572)

    One option being considered is spinning the wheels on one side in the hope of tilting the solar panels to face the winter sun. Even if Spirit never travels again, all is not lost. There is a radio experiment for measuring the wobble of Mars as it spins that requires the rover to stay in one place. The key is surviving the upcoming winter, which may depend on a fortuitous wind blowing accumulated dust off the solar panels.

  • by khallow (566160) on Monday January 04, 2010 @12:59PM (#30642590)

    Clearly the rover isn't making much progress with it's 'dead foot' stuck in the sand, so why can't we cut it off?

    As I understand it, there are no "stuck" feet. The rover simply doesn't have the traction (perhaps combined with low motive power) to leave this area of sand.

  • Re:Way to go, NASA! (Score:4, Informative)

    by Guysmiley777 (880063) on Monday January 04, 2010 @02:13PM (#30643616)

    The USSR bounced plenty of probes off and past Mars before and after the Mars 3 lander. Getting onto the surface of Mars is no trivial task. I think they had 7 failures (not including launchpad kerfuffles) where the probe either stopped responding, missed the planet or created a new crater.

  • Weight. If you use nuclear power source, you've got to bring your fuel with you, where as with solar, the fuel is already packed away safely in the sun; you just need to bring a collector. Mars, unlike the outer planets, is still close enough to the sun that you get a reasonable amount of power from solar cells, if you have enough square footage, so solar wins the power/weight ratio contest. Besides, these things weren't built to survive the winter at all; the design requirements only called for three months.
  • by Chris Burke (6130) on Monday January 04, 2010 @02:58PM (#30644252) Homepage

    I though they did not use electric heaters on the rovers but used radioactive heating and aerogel insulation..

    You are correct that they do have a radioisotope heater and aerogel insulation, but they do use electrical heating as well to augment the base level created by the radioisotope heater. Without electrical power, it most likely won't have enough heat to survive winter.

  • by tlambert (566799) on Monday January 04, 2010 @03:05PM (#30644330)

    "The rovers run a VxWorks embedded operating system on a radiation-hardened 20 MHz RAD6000 CPU with 128 MB of DRAM with error detection and correction and 3 MB of EEPROM. Each rover also has 256 MB of flash memory. To survive during all of the various mission phases, the rover's vital instruments must stay within a temperature of 40 C to +40 C (40 F to 104 F). At night the rovers are heated by eight radioisotope heater units (RHU) which each continuously generate 1 W of thermal energy from the decay of radioisotopes, along with electrical heaters that operate only when necessary. A sputtered gold film and a layer of silica aerogel are used for insulation."

    http://en.wikipedia.org/wiki/Mars_Exploration_Rover [wikipedia.org]

    -- Terry

  • by tlambert (566799) on Monday January 04, 2010 @03:30PM (#30644664)

    Tthe OS reboots periodically if there's no communication to ensure that it doesn't hang because of the OS. It's a hardware watchdog, which is NOT shut down when the rover is put to sleep, so it will wake periodically over the winter, try to establish communications, ask for a software update (if any), and then go back to sleep. Given that the original mission anticipated a 90 life expectancy, expect these reboots to be relatively frequent.

    http://www.flightsoftware.org/files/FSW08_Deliman.pdf [flightsoftware.org]

    -- Terry

  • by Tablizer (95088) on Monday January 04, 2010 @05:19PM (#30646398) Homepage Journal

    I really wonder if the Rock Abrasion Tool (RAT) arm (the grinder arm) is strong enough to help Spirit move away from its sand trap

    I've read that its motor is simply not nearly powerful enough. And it risks damage to the instruments, which perform its primary job. As I remember it, they said they might try it if they felt it needed only slightly more lift to achieve freedom. But so far the math doesn't favor it. It's not even close to the threshold where it may help.
       

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