I know what the SAM team had at AMASE in 2010 and this was not a flight spare of SAM. This article is from 2006 and so I doubt that the machine was a 100% representative for SAM. Adn I doubt that they would write in an article that they encountered a rock which looked empty but in fact had organics.

I am sure that they also encountered some rocks which looked empty, so it is very dependent on the rock. There are mudstones which are nearly organic free and with those even SAM would have difficulties.

The amount of organic they need for a detection is very low and a most mudstones here on earth would give a nice signal.

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

The detection level is a very complicated topic for all pyrolysis based systems. It is hard to determine the exact numbers because the extraction efficiency of pyrolysis is depending on:

*the chemistry of the rock; oxidative and reductive compounds will have a significant influence catalytic surfaces will influence the result

*the distribution in the rock; strongly encapsulates org. molecules or strongly adsorbed org. molecules are hard to get out of the rock

*the compound; there are compound which decompose very easy into CO, CO2 and N2 and you will not see an organic molecule at all the same for the kerogenic substances which are hard to detect because of the high boiling points.

The comparison with extraction techniques often shows you that what you expected is a lot different in reality.

With the 1ppb detection level there will be hardly a chance that they will not detect anything in the coming months of the mission. If they find nothing in the next few years Mars has an unknown mechanism to get ride of organics.

But don't we already know Mars has/had organics - from Martian meteorites?

Yes, from:
http://www.lpi.usra.edu/meetings/lpsc2013/pdf/1476.pdf

But we don't know what effect the MTBSTFA leak will have, right?

See Don1's post 77. The pressing question is whether Curiosity will find organics and if so, what her instruments will tell us about them.

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.

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!

From what I can tell, the actual press conference in Washington is out of the ordinary. Maybe they really did find something? Likewise, I do not expect life on Mars, but I would imagine they have a high level of confidence in their data to deviate from the normal method of releasing their results.

Repeat: Don't get too excited. This will be an announcement about the first-ever chemical composition derived for a Martian rock, and probably a victory lap for the SAM team since the instrument will have been proven to operate properly (to say nothing of the complex drilling/sorting arm hardware).

I'd wager that the presser will be 90% milestone achievement, 10% findings.

Agree with nprev.

Analysis by CheMin and SAM of a drilled sample is a major milestone for Curiosity, whatever the result.
That in itself would merit the T.V. briefing from NASA HQ.

Looking forward to whatever is presented.

Craig

But the SAM and Chemin instruments and not to mention the complex CHIMRA sorting mechanism were all proved to be working many months ago at rocknest. To be honest im more interested in a update on MSL's operational status right now - what's the deal with that anyway?

True--in terms of announcing subsystem firsts, they kind of declared everything working at the last telecon. I hope that reporters ask about the current status of the computer.

Today's announcement looks like a mixture of good and bad news. The good news is that habitability potential is high. There is liquid water which is close to neutral and not too salty. There is food. There are nutrients like nitrogen and phosphorous. There are clays which are good for trapping organic matter, and the environment is not highly oxidizing. The one remaining issue is how persistent the wet conditions were. The geologists indicated that the wetness might have been intermittent, but they didn't rule out a long lived lake, which would be much better for habitability.

The bad news is that the rocks contain perchlorate, which will make detecting organics much more complex and ambiguous. Perchlorate is extremely soluble, so it was likely washed into the rocks by groundwater long after the rocks formed. SAM has a big bag of tricks, so we will have to wait and see what the instrument can do with this sample.

The D/H ratio seems to be a lot different from modern values, so that points to an old deposit. It will be compared to Martian meteorites, and with luck it may provide a relative age for Glenelg.