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Mars NASA Space Science

NASA Rover May Contaminate Its Samples of Mars 147

Posted by Soulskill
from the no-problem-just-launch-another-one dept.
sciencehabit writes "The Curiosity rover will definitely find evidence of an advanced civilization if it lands safely on Mars. That's because rock samples the rover drills are likely to be contaminated with bits of Teflon from the rover's machinery, NASA announced during a press teleconference. The bits of Teflon can then mix with the sample, which will be vaporized for analysis. The problem for the scientists is that Teflon is two-thirds carbon — the same element they are looking for on Mars." Fortunately, this problem isn't a showstopper: "...there are still mitigation steps to take if SAM's analysis is potentially compromised. Contaminant production appears to be stronger in the drill's percussion mode, when it pounds powerfully and rapidly on Martian rock. So ratcheting the percussion down, or switching over to the more gentle rotary mode, may make the issue more manageable. If that doesn't work, the MSL team could just take the drill out of commission, solely scooping soil instead of also boring into rock. Curiosity could still access the interior of some Martian rocks by rolling over them with its wheels, Grotzinger said. But all in all, he's confident that the team will figure things out in the next month or two."
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NASA Rover May Contaminate Its Samples of Mars

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  • by BradleyUffner (103496) on Tuesday June 12, 2012 @03:21PM (#40299567) Homepage

    Right now, the rover is in *space*. I can definitely understand catching this problem in simulations or in on-Earth tests, or catching it belatedly when they finally get to Mars and wonder why all the rocks contain fluorine, but in space? Only thing I can think of is "someone re-ran some simulations and noticed they messed up", which doesn't seem very probable (unless the engineers had been suspecting this since before launch, and only now have sufficient "proof").

    Then again, I'm not a rocket scientist, so I probably missed something.

    They probably have an identical unit to mess with locally in case of electrics problems. If something goes wrong in space it is extremely helpful to have a physical replica you can actually put your hands on and experiment with to find the best fix.

  • by Baloroth (2370816) on Tuesday June 12, 2012 @03:23PM (#40299595)

    I don't know how sensitive the detector they are using is, but they should also be able to detect the fluorine molecules (which outnumber the carbon 2 to 1, unlike what TFA claims). I don't imagine they expect to find a lot of fluorine in the rocks on Mars, so the presence of fluorine indicates the sample is contaminated and they should ignore the carbon. If the analysis is really sensitive, they could even correlate the amount of fluorine with the expected amount of carbon (since it should be exactly 2 to 1), allowing the contaminating carbon to be eliminate from the analysis.

    This assumes the fluorine can be accurately analyzed, which may be a major issue since it is extremely reactive. I'm not a chemist, though, so I don't know how big an issue that could be.

  • by Solandri (704621) on Tuesday June 12, 2012 @07:21PM (#40302629)

    Why didn't someone say, "Presume the test is positive -- let's shoot holes in it." them iterate proving the test until there are no more holes they can think of.

    Is that so hard before you spend billions?

    The flip side is spending tens of millions thinking of all the possible ways the test could provide a false positive, designing them out of the test, then sending Viking to Mars and having the test come out negative. Then you get criticized or wasting all that money coming up with a test which would generate a foolproof positive result, forgetting that the result could be negative.

    Science is like filling an empty map. If you blindly concentrate all your resources in one area of the map, you could end up knowing a lot about an uninteresting place (like say, the middle of the ocean). But if you use a shotgun strategy and first spend minimal resources in lots of locations, you can see where the interesting parts of the map are and concentrate your resources on exploring those in the future.

    Viking was the first Mars lander. By no means was it planned to be the last. They put a simple experiment (along with several others) on board which would provide a quick answer to a "gee I wonder what happens if..." question. If it came back negative, oh well. Since it came back positive, then they could spend millions scrutinizing the result and planning a better test for future landers.

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