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NASA's Phoenix Finally Fills Oven

Posted by timothy on Wed Jun 11, 2008 03:58 PM
from the ask-your-doctor-if-staminex-is-right-for-you dept.
Mars NASA Space Science
JoeRobe writes "Phoenix has successfully filled oven #4 of the Thermal and Evolved-Gas Analyzer instrument (TEGA). They have spent several days now vibrating the screen above the oven, trying to get a significant amount of soil sample into it. From the article: '[T]he oven might have filled because of the cumulative effects of all the vibrating, or because of changes in the soil's cohesiveness as it sat for days on the top of the screen.' Either way, this is the first step toward getting some interesting data from this instrument."
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Submission: NASA's Phoenix Finally Fills Oven by JoeRobe (207552)
[+] Mars Phoenix Lander's Ovens Were Destined To Fail 77 comments
RobertB-DC writes "The Phoenix mission to Mars' frigid polar regions was going to be tricky from the start, with only a few weeks to perform as much science as possible. Success depended on everything working right. But one of the mission's most frustrating glitches — the stuck doors on the TEGA ovens — could have been prevented with basic quality control on Earth. Nature is reporting that bad brackets were replaced by the manufacturer ... with identically bad brackets. The Planetary Society blog sums it up succinctly: 'Ouch. Ouch ouch ouch.'"
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  • Cookies (Score:4, Funny)

    by LeoDavinci578 (795523) on Wednesday June 11 2008, @04:02PM (#23754677)
    Who wants cookies?

  • invalidate the tests (Score:5, Interesting)

    by phrostie (121428) on Wednesday June 11 2008, @04:03PM (#23754689)
    couldn't this invalidate the tests.

    it seems to me that the clumps could be caused by the very ice we are looking for.
    by screening it out, the samples won't be representative of the soil
    • From my limited understanding of the properties of H2O on mars, I would imagine that letting a clump of dirt sit up above the soil would cause the ice to sublime after being directly exposed to sunlight. Anyone know if this is possible? Obviously they aren't going to get a false positive... but a false negative seems likely (although I'm sure that they will know this if it happens to be the case, and will try again to find water).

      • Re:invalidate the tests (Score:4, Insightful)

        by osu-neko (2604) on Wednesday June 11 2008, @04:31PM (#23755077)
        There's no such thing as a "false negative" for the kind of tests they're doing. They're not conducting the kinds of experiments that would falsify a theory. The only results possible from the tests they're doing are "confirmed" or "failed to confirm" (and nothing much can be concluded from the latter in any case).

        • Re: (Score:3, Informative)

          by eonlabs (921625)
          What I'm sure the 'grandparent' article is referring to as a false negative is that if there were water (ice) in the original sample when it was taken, there's a risk that several days vibrating it in under low atmospheric pressure may cause it to evaporate. If it's a small enough sample, or the pressure is low enough, it could sublime, converting directly from ice into steam.

          This would result in a false negative if the original sample did, in fact, contain water, because spending that much time between ga

        • Re:invalidate the tests (Score:5, Informative)

          by Anonymous Coward on Wednesday June 11 2008, @06:31PM (#23756603)
          Phase diagram of water: http://www.lsbu.ac.uk/water/phase.html [lsbu.ac.uk]

          Note the portion where solid and vapor phases are adjacent with no liquid phase in between (sublimation/deposition).

        • Re:invalidate the tests (Score:5, Informative)

          by petermgreen (876956) <plugwash@noSpAM.p10link.net> on Wednesday June 11 2008, @06:55PM (#23756893) Homepage
          Water doesn't sublime.
          It does if the pressure is low enough, I think on mars there would be a liquid phase though it would be much much narrower than on earth such that it would be almost too narrow to notice.

        • Re: (Score:2, Informative)

          by tweak13 (1171627)
          Water Ice sublimes even in the earth's atmosphere. Ever wonder why ice cubes shrink after they've been in a freezer for a really long time? It's also the reason that all the ice will "melt" off your car if you expose it to the sun, even if it's below freezing out. Freezer burn on your food is also caused by sublimation. So yes, water ice does sublime, and in low pressures would probably do so even more.

          • Ever wonder why ice cubes shrink after they've been in a freezer for a really long time?
            I know. I also prefer to use deuterium ice.

        • Re: (Score:3, Informative)

          by Ihlosi (895663)
          Water doesn't sublime.

          I have a phase diagram of water here that disagrees with you (and anyone who modded you informative. geez, people, hand in your geek licenses please).

          See that boundary line in the lower-left corner, where vapor and ice are directly adjacent to each other ? That's where water sublimes.

          http://encarta.msn.com/media_461541579/phase_diagram_for_water.html [msn.com]

    • Re: (Score:3, Insightful)

      by osu-neko (2604)

      couldn't this invalidate the tests.

      I don't think so. What would they be testing for that would be invalidated by this? If they find presence of life, or evidence of past life, the fact that they screened something out doesn't invalidate what they found in what was left. If they fail to find anything like that, there's no valid conclusion that could be drawn in any case (absence of evidence is not evidence of absence), so a conclusion of "there's no life and never was" would be invalid regardless of whether parts of the sample were scree

      • Re: (Score:2, Interesting)

        by jessemerriman (934509)

        (absence of evidence is not evidence of absence)

        Yes, it is:

        Absence of proof is not proof of absence. In logic, A->B, "A implies B", is not equivalent to ~A->~B, "not-A implies not-B".

        But in probability theory, absence of evidence is always evidence of absence. If E is a binary event and P(H|E) > P(H), "seeing E increases the probability of H"; then P(H|~E) < P(H), "failure to observe E decreases the probability of H". P(H) is a weighted mix of P(H|E) and P(H|~E), and necessarily lies be

        • While I'm sure you think you're being clever, in this instance absence of evidence is not evidence of absence. Just because I can't find evidence of a platypus outside my house does not prove that no platypuses(platypae?) exist on the planet. The mere fact that the page you referenced singles out probability theory as the exception should have been enough to figure out that maybe your assertion has limited application.

      • Re: (Score:2, Insightful)

        by cetitau (951106)
        I don't want to sound like an expert in this field but I don't understand this response. This science doesn't look for life. Here it's looking for some specific chemical content in the oven at the conclusion of the test. If clumpiness was a result of soil mixed with frozen volatiles, i.e. soil particles stuck together by water or other ices, then evaporation of the volatiles over these days of shaking could certainly alter the outcome. I believe none of these tests are designed to prove or disprove the

      • Re: (Score:3, Funny)

        by antic (29198)
        "If they find presence of life..." ...let's cook it!
    • My first instinct was to dismiss your concern outright. I mean why wouldn't they have tested the apparatus in a lab on earth, before sending it to mars? But NASA is capable of making mistakes on complex missions,as we saw from the mars climate orbiter experience [cnn.com]From that incident we got this priceless quote:

      "People sometimes make errors," said Edward Weiler, NASA's Associate Administrator for Space Science in a written statement.

      • another thing to realise is that afaict martian "soil" isn't something we have a huge ammount of experiance with. All our knowlage comes from instruments on probes which are way way behind what we have on earth.

        has anyone even tried sieving the stuff before?

        • has anyone even tried sieving the stuff before?
          No. But I thought they could have done better than spreading a mountain of the stuff over the oven lids when they only needed a few grains. They have contaminated the other ovens.

      • Re:invalidate the tests (Score:5, Informative)

        by Anonymous Coward on Wednesday June 11 2008, @06:26PM (#23756555)
        It is a real concern, but it isn't a mistake.

        The JPL engineers who designed it knew from the start that certain compounds, including water ice, would begin to sublimate once the soil was disturbed. For this reason, they wanted to get the samples into the chamber relatively quickly. It is very likely that the 3-4 day delay caused some loss of volatiles. It doesn't completely invalidate this sample because it's unlikely that all the ice sublimated, and water isn't the only thing they're looking for.

        Also, there are 7 other chambers in this instrument, and they believe they've figured out how to avoid this trouble in the future.

        They did test the aparatus pretty thoroughly on earth, but the soil properties ended up being quite a bit different from what they expected. No mission before has handled soil in quite the way Phoenix does, and the soil at the north pole may well be different from that in locations where previous landers have touched down.

    • couldn't this invalidate the tests. it seems to me that the clumps could be caused by the very ice we are looking for.

      The instrument in question isn't looking for ice, but is measuring the chemical properties of the soil.

    • Re:invalidate the tests (Score:5, Informative)

      by SiliconEntity (448450) on Wednesday June 11 2008, @05:44PM (#23756037)
      This is just the first test. At this point, Phoenix is supposed to be testing the soil, not the ice. Later, they are going to dig down into the ice. They have a special drill-like object on the digging tool which will drill into the ice and produce fine shavings. These shavings will then be scooped up and dumped into the oven. But that will come later, first they are testing the soil. This is what has been a problem so far, it's good that they have managed to make progress with it.

      • Re: (Score:2, Informative)

        by osu-neko (2604)

        Flawed data is better than no data. Right?

        No. But that's not the issue here. What we're talking about here is getting less data than we'd like (because of what was excluded from the sample). Data is not "flawed" for being a smaller quantity, it's just, less. Some data is better than no data at all.

        • Re: (Score:3, Insightful)

          by profplump (309017)
          Why isn't "flawed data" at least sometimes the same as "some data" and therefore better than "no data"?

          For example, what if you had a rain meter that leaked -- you couldn't accurately determine accumulation, and you couldn't conclusively ascertain that no water had fallen just because it was empty, but if the meter read 1.28" when you looked at it you could conclude that at least 1.28" of water had fallen since last time the collector was drained. The 1.28" reading would flawed, but the device would still p

  • Too much vibration... (Score:5, Funny)

    by Volante3192 (953645) on Wednesday June 11 2008, @04:16PM (#23754877)
    Great, now all Phoenix is going to say to NASA is TILT!

    We're gonna have to fly someone up there to deposit a dollar in quarters into Phoenix now...

  • What were they thinking? (Score:3, Interesting)

    by elrous0 (869638) * on Wednesday June 11 2008, @04:16PM (#23754889)
    Why would they have designed the thing to have such a low tolerance filter in the first place? Hell, most *terrestrial* soil wouldn't even make it into that oven. I sure wouldn't use it for a soil whose composition was largely a mystery. And, even if they get something, will it truly be representative of the Martian soil, or just the finest particles of it that finally made it through?

    • Re:What were they thinking? (Score:5, Insightful)

      by SBacks (1286786) on Wednesday June 11 2008, @04:27PM (#23755035)

      Why would they have designed the thing to have such a low tolerance filter in the first place?
      Cuz they had to strap it on a rocket and shoot it to Mars? I kinda doubt a full sized lab furnace would be under the weight requirement.
    • Why would they have designed the thing to have such a low tolerance filter in the first place?

      Probably because heating a larger amount of soil would have been too much of a drain on the batteries of the thing.

      But I agree. 1 mm diameter particles are tiny.

      • Re:What were they thinking? (Score:5, Funny)

        by Sponge Bath (413667) on Wednesday June 11 2008, @04:45PM (#23755263)

        1 mm diameter particles are tiny.

        For the common man who needs a frame of reference: This is the same length as the distance between the solder balls of many BGA IC packages.

        • Re:What were they thinking? (Score:5, Informative)

          by Changa_MC (827317) on Wednesday June 11 2008, @04:54PM (#23755351) Homepage Journal

          1 mm diameter particles are tiny.
          For the common man who needs a frame of reference: This is the same length as the distance between the solder balls of many BGA IC packages.
          Good lord, that didn't help him at all. For the common man: a dime is about 1mm thick.
        • 1mm isn't really all that small.

          Thing is that under a BGA you need a grid of vias and if you don't want to use blind vias (which are expensive and complicate the design process) you have to get tracks between the vias.

          If you have a minimum hole size of .25mm and a minimum track gap and annular ring of .1mm (theese are not hypothetical figures, they are zot's "standard production" figures). With a 1mm pitch BGA you can get two tracks between a pair of vias on each layer. With an 8mm pitch BGA you only get o

    • Re:What were they thinking? (Score:5, Insightful)

      by drrck (959788) on Wednesday June 11 2008, @04:43PM (#23755227)
      We're talking about introducing material into an oven to be vaporized for Mass Spec analysis. You don't want or need to deal with huge amounts of material to tell what compounds are in the soil.
      • You don't want or need to deal with huge amounts of material to tell what compounds are in the soil.

        You also don't want half of the contents to sublimate by leaving them exposed to sunlight and friction/heat from a vibrating screen. Considering how important it was to land where there was ice (polar landings are tough) you think they would be a bit more careful to preserve that ice since that is where they hoped to find the organic compounds.

  • Hooray (Score:5, Funny)

    by Haoie (1277294) on Wednesday June 11 2008, @04:18PM (#23754919) Homepage
    We've come along way from the Easy-Bake Oven.

    But I still bet the Phoenix can't make smores.

    • But I still bet the Phoenix can't make smores.

      It could but it would require 1mm graham crackers and marshmallows.

  • it's no turkey (Score:5, Funny)

    by nguy (1207026) on Wednesday June 11 2008, @04:21PM (#23754961)
    To their surprise, NASA scientists discovered that, try as they might, roasting a phoenix in an oven never results in well-done meat.
  • Let the baking begin.

  • Will it blend? (Score:4, Funny)

    by kharri1073 (1036550) on Wednesday June 11 2008, @04:40PM (#23755191) Homepage
    They should have consulted willitblend.com before they sent the craft to mars. I'm sure the people at will it blend would have had no problems getting some martian dirt through a micro screen.
  • ...you didn't want a bun in the oven.
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    But first, a word from our sponsors:

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    K'breel said that the creature was only paralized and not destroyed so the Council would have more time to think of an effective plan. The public cheered when they heard speaker K'breel say the following words:

    What is important is that the metallic creature does not record any sign of intelligence under our beloved red sky. But do not be afraid, for soon we will elliminate it, making it look like an accident.
    When a subversive traitor accused the speaker for the most Illustrious Council that the slowdown was simply a malfunction in the metallic creature's machinery, K'breel ordered to have him imprisoned and executed tonight for High Blasphemy.
  • From my reading of the FA, it seems that oven #4 is the first oven they tried. That's important, because it seems that whether the soil gets there or not, they only get one try with each oven. So they still probably have 7 more to go. Hurrah, NASA!

    • Re:Once again... (Score:5, Interesting)

      by Anonymous Coward on Wednesday June 11 2008, @06:36PM (#23756673)
      The actual oven is only about 1 mm in diameter. The screen covers a funnel that directs a small sample of soil into the oven. What happens when you let a 2 mm particle fall on a 1 mm oven? That's right...it cover the opening and nothing else gets in.

      Believe it or not, there are people at NASA and JPL capable of seeing the big picture.

      In this case, the soil turned out to be clumpier than anyone expected, and before you ask, yes they did try to determine what it would be like before launch, using data from the Vikings and the rovers.
    • > These folks aren't blinded by minute details and generally see the big picture. Tell me. How exactly does having the "big picture" allow you to see one flaw in a million little details? By definition of "big picture", the details are missing from it.
      • Wow, by your username, signature, and response I'm going to lump you into that "egghead" class I spoke earlier of and say that you are reading waaaay too much into an offhand comment on a slashdot story. I think you know what I meant.

        I can't tell you how many times totally non-technical people have come up with crazy analogies that actually match a particular complex situation that you would never expect them to even begin to grasp. As much as I hate to admit it, the average scientific/tech type is generall

    • Re: (Score:3, Insightful)

      by Ihlosi (895663)
      its depressing how feeble and unreliable the space probe design are compared to the insane amounts of investment.

      And you're ... qualified to make this statement ? Are you any kind of engineer (ME or something along those lines would be best) ?

      shovel, to scoop up dirt, instead of some decent drilling apparatus that could get samples from much deeper and from harder surface.

      Yes, of course, a drill. How brilliant. So where do you get all the power to run that drill ? How do you keep it lubricated ? H

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