MSL - SAM and CHEMIN, Discussion of the science/results from these instruments |
MSL - SAM and CHEMIN, Discussion of the science/results from these instruments |
Nov 21 2012, 11:46 AM
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Senior Member Group: Admin Posts: 3108 Joined: 21-December 05 From: Canberra, Australia Member No.: 615 |
ADMIN NOTE: Hi All, a new topic for the discussion of the science from the SAM and Chemin instruments.
There has been a very important amendment to Rule 1.3 which is explained here. Please remember Rule 1.3 at all times when discussing matters in this section. |
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Dec 5 2012, 02:01 AM
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#2
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Junior Member Group: Members Posts: 94 Joined: 11-August 12 Member No.: 6536 |
I think we're looking at a work in progress with the SAM results. They don't really have publication grade scientific results but they do have some very interesting data and hypotheses.
The most interesting is the detection of the chlorinated hydrocarbons, which are mostly chloromethanes. These showed up in Viking results on Mars, but were not seen in pre-flight tests of the Viking instrument. Chloromethanes are good solvents and cleaning agents. For instance CCl4 is used for dry cleaning. The Viking results were written off as contamination of the sample handling system by cleaning agents. After the discovery of perchlorates, Chris McKay pointed out that a perchlorate containing soil would convert any organics it contained into chloromethanes on heating. He suggested that Viking did indeed detect Martian organics, but that the data was misinterpreted because the presence of perchlorate in the soil was unknown at the time. I think the detection of chloromethanes by SAM puts a big question mark over the interpretations of Viking data, including the Viking conclusion that the Mars soil did not contain organics. The non-detection of organics by Viking was a very important result that drove the interpretation of some of the odd data produced by the other experiments. However, SAM still has contamination issues of their own to sort out, including evidence that the rover is shedding plastic on the soil and hints that there might be a leak of organic reagent inside the instrument. People are also suggesting ways to make chloromethanes from purely inorganic reagents like CO2, water and perchlorate. So at this point there are viable hypotheses that explain the data without needing Martian organics. Only time will tell which is correct. |
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Dec 5 2012, 02:20 AM
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Founder Group: Chairman Posts: 14434 Joined: 8-February 04 Member No.: 1 |
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