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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Mar 10 2013, 09:38 AM
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Junior Member Group: Members Posts: 94 Joined: 11-August 12 Member No.: 6536 |
Many Mars meteorites contain organics at levels that are very detectable by SAM. Amino acids at 100ppb levels have been reported. There is some controversy over the origin and these might be terrestrial. A high temperature Martian origin seems to be the favored explantion. Levels of reduced carbon in the 1-50 ppm range have also been reported, and this would be easily detected by SAM.
The bottom line is that there is a good chance that SAM will detect traces of organics in the next few months if it hasn't already. IIRC the detection limit for SAM is 1ppb organics. Amino acids in mars meteorite Reduced organic carbon in mars basalts |
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Mar 10 2013, 03:22 PM
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Senior Member Group: Members Posts: 4256 Joined: 17-January 05 Member No.: 152 |
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Mar 10 2013, 08:17 PM
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Junior Member Group: Members Posts: 94 Joined: 11-August 12 Member No.: 6536 |
But we don't know what effect the MTBSTFA leak will have, right? The effect of the leak depends upon the presence of perchlorates in Martian rocks, which Tuesday's briefing should discuss. Hopefully they won't be found. If perchlorates are present, well SAM has a big bag of tricks and some of those can be used to deal with the problem. The wet chemistry cells can react away the perchlorate and enable the detection of organics that might be present. There is a very limited supply of those cells, perhaps more limited now that some have leaked. |
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Mar 10 2013, 09:46 PM
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#5
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Junior Member Group: Members Posts: 93 Joined: 21-January 13 Member No.: 6845 |
The MTBSTFA gives you a nice background and makes the search for the very small peaks more difficult. All the spots of large peaks you lose for your science. The perchlorate gives you another bunch of peaks, the small mono- di- and tri-chloromethanes. With the knowledge that perchlorates oxidise a lot of the present organics and transforms another share to chlorohydrocarbons you now have to guess how much of the chlorohydrocarbons you detect are from the MTBSTFA or from some other source. So the leak of MTBSTFA or the use to save the organics from the perchlorates makes analysis complicated and gives you a headache to make the case that you really have found something.
I hope for perchlorate free sample at some point of the mission. I expect nothing special, like life on Mars or abundant organics, on Tuesday! |
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