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Conflicting Results from Phoenix Science Instruments Prompts Further Study

Soil in Mars Arctic Region.  Credit: NASA/JPL/Caltech/ U of Arizona

Soil in Mars Arctic Region. Credit: NASA/JPL/Caltech/ U of Arizona

Scientists from the Phoenix lander are analyzing conflicting results from soil samples delivered to two science instruments on the Mars lander. Two different samples analyzed by the spacecraft’s Wet Chemistry Lab both suggested one of the soil constituents may be perchlorate, a highly oxidizing substance that is considered toxic. But results from the TEGA instrument, (Thermal and Evolved-Gas Analyzer) downloaded from the lander over the weekend indicated no evidence of perchlorate. These findings may may have prompted the reports of “provocative” science results recently. Today, Phoenix officials said any reports of the spacecraft finding life were unfounded, and over the weekend, the Phoenix spacecraft itself said, via Twitter, that reports of White House briefings were not true. NASA will hold a media teleconference on Tuesday, Aug. 5, at 2 p.m. EDT, to discuss the recent science activities. A press release from the Phoenix team today said, “Confirmation of the presence of perchlorate and supporting data is important prior to scientific peer review and subsequent public announcements.”

Scientists said that while the conflicting results are unexpected, they are working hard to understand the soil chemistry and mineralogy in the Mars northern arctic region.

“This is surprising since an earlier TEGA measurement of surface materials was consistent with but not conclusive of the presence of perchlorate,” said Peter Smith, Phoenix’s principal investigator at the University of Arizona, Tucson. “We are committed to following a rigorous scientific process. While we have not completed our process on these soil samples, we have very interesting intermediate results,” said Smith, “Initial MECA analyses suggested Earth-like soil. Further analysis has revealed un-Earthlike aspects of the soil chemistry.”

The team also is working to totally exonerate any possibility of the perchlorate readings being influenced by terrestrial sources which may have migrated from the spacecraft, either into samples or into the instrumentation. One type of perchlorate, ammonium perchlorate, is sometimes used as an oxidizer in rocket fuel.

“When surprising results are found, we want to review and assure our extensive pre-launch contamination control processes covered this potential,” said Barry Goldstein, Phoenix project manager at NASA’s Jet Propulsion Laboratory.

An article on AviationWeek.com reported August 1 that the US president had been briefed on findings from Phoenix, and NASA would be ready to reveal the findings in mid-August. An article on Universe Today was based on that report. Today, Aviation Week & Space Technology stands by its report, saying that “the new information involves the “potential for life” on Mars. That potential can either be positive or negative, and the new data indicate the new soil tests are at best inconclusive, according to the information being released on the soil chemistry experiment.”

Phoenix’s Wet Chemistry Lab is part of the Microscopy, Electrochemistry, and Conductivity Analyzer, or MECA instrument which studies soluble chemicals in the soil by mixing a soil sample with a water-based solution with several reagents brought from Earth. The inner surface of each cell’s beaker has 26 sensors that give information about the acidity or alkalinity and concentrations of elements such as chloride or perchlorate. The beaker also can detect concentrations of magnesium, calcium and potassium, which form salts that are soluble in water.

The TEGA instrument has tiny ovens that heat soil samples, and analyzers that “sniff” vapors released from substances in a sample.

Original News Source: Phoenix News


Nancy Atkinson is currently Universe Today's Contributing Editor. Previously she served as UT's Senior Editor and lead writer, and has worked with Astronomy Cast and 365 Days of Astronomy. Nancy is also a NASA/JPL Solar System Ambassador.

Comments on this entry are closed.

  • Ralph Rewes August 5, 2008, 6:27 PM

    I fail to see the political point on these “findings” and the delay to make them public. Io Tru02 is partially right.

    Why doesn’t NASA publish all the photos taken? Why the mystery? What is really going on.

    Why they adamantly refuse to answer all questions. We all are interested.

    As for you in this forum, thank you for censoring my last comment.

  • John August 5, 2008, 6:56 PM

    Because these results are not from photos, they are from TEGA and MECA which are not imagers, they involve a lot of data that is not as simple as a picture.

    They are scientists doing their job, they do not have to publish a realtime analysis of their findings, and doing so would be scientifically irresponsible.

    The only reason people are acting like there is some kind of hype is because there is the possibility they could announce some findings regarding the habitability of a teaspoon sized spot on Mars. These findings are only a small part of the scientific bulk being unleashed by the very successful Phoenix mission and its scientists.

    To diminish their success because you get in an uproar over the mass media’s sensationalist headlines is ridiculous and sad.

  • John August 5, 2008, 7:03 PM

    Also, for those complaining about the lack of communication which you seem to feel is their responsibility, here is the link to the most recent announcement by the Phoenix Team which should answer lots of your questions, but will no doubt leave you convinced that there is a great universal conspiracy against your ability to gain knowledge.


    I would also suggest that something be posted here in regard to the statement ‘conflicting results’. It appears that the MECA team does not believe their lack of detection of perchlorate contradicts the findings from TEGA.

  • Al Hall August 5, 2008, 7:45 PM

    I’m with John…. Let us see what happens. No reason to jump to conclusions.
    Example: Up until a couple of days ago I thought the Huygens probe was pretty much a failure. It took a couple of pictures for a couple of seconds, but that was pretty much it… Now (after more than three years) we may be getting some data analysis from it…. So……………

  • Jorge August 5, 2008, 7:46 PM

    I would advise everybody to listen to the media briefing the Phoenix team issued today (available here. It’s rather lengthy (1 hour) but clears up a lot of things, tries (unsuccessfully, I’m sure, but quite effectively as far as I’m concerned) to put the cork back in the speculation bottle, and the team says a thing or two very relevant to the whole life on mars issue.

    In a nutshell, it’s not 100% certain that it was indeed perchorate that was found, they are still testing other possible explanations for the experimental results (as stated in this article here), but the case for perchlorate is strong. The journalists made a lot of questions about what perchlorate is, where it can be found in nature and what its impact might be for past or present martian life. The answers were pretty clear. I retained two things in particular: there’s still a whole lot to be learned about those molecules and their interaction with organic molecules in general and living organisms in particular, but they (or some perchlorates at least) can interact without causing much damage and even with the potential to be used as energy source. The fact that perchlorates are found on Earth’s Atacama Desert, where a thriving microbial community has its habitat, was mentioned several times.

    The other thing that stood out for me was that, since percholates are ionic compounds, they dissolve very easily in water and therefore, under Earth conditions, are very efficiently washed away from the soil except in very dry climates. This means that once we find a way to have liquid water contacting with martian soil (inside labs, in pressurized modules, even in domes or whatever), the removal of these compounds from the soil would be pretty much an immediate consequence of adding water to it.

    Whatever the result turns out to be on the perchlorate front, the bunch of surprises Phoenix dug up (literally) until now leads me to strengthen my opinion that we need many more robotic missions to Mars before even thinking to send people there. I don’t think we know nearly enough of how the planet works to prepare a crew for a stay of a couple of months in it. Perhaps a whole fleet of Spirit-like rovers in addition to missions like the MSL wouldn’t be such a bad idea. The cost of development would be zero and even if the outcome is smaller than that of the two pioneer rovers it’d probably be worth it.

  • Jon Hanford August 5, 2008, 7:46 PM

    Thanks go out to John for the link to the relevant Phoenix press release. I agree with him that at this very early stage of the analysis of instrumental results, no conflicts exist at this time between MECA & TEGA instruments. Detailed peer-reviewed analysis of measurements made by Phoenix may take months( or years ) and I see no reason for any rush to judgement or ‘conspiracy theories’ at this time. Proper scientific analysis takes time, so what’s the rush? Also, might detection of perchlorates only pertain to this particular site? Mars is a big place, so might it be possible this is only a local occurance? Why not give the scientific community some time to digest & analyze the data?

  • Jorge August 5, 2008, 8:02 PM

    They also discussed the local or global presence of these substances in the briefing. The common assumption is that, given the fact that the planet is periodically engulfed by a global dust storm, whatever substances that are found in superficial sediments should be more or less the same around the globe. But this is only an assumption, of course. To be sure, more places should be studied.

  • steven August 11, 2008, 6:34 AM

    ‘…Much Ado about Nothing…’ Shakespeare