Topic: Mars robots may have destroyed evidence of life (Read 1996 times)

Nemesis · « **on:** May 27, 2009, 02:11:54 pm »

Quote

At low temperatures, perchlorates are relatively harmless. But when heated to hundreds of degrees Celsius they release a lot of oxygen, which tends to cause any nearby combustible material to burn. For that very reason, perchlorates are used in rocket propulsion.

The Phoenix and Viking landers looked for organic molecules by heating soil samples to similarly high temperatures to evaporate them and analyse them in gas form. When Douglas Ming of NASA's Johnson Space Center in Houston, Texas, and colleagues tried heating organics and perchlorates like this on Earth, the resulting combustion left no trace of organics behind. Ming's team presented their results at the recent Lunar and Planetary Science Conference in Houston.

Iron oxides have also been suspected of interfering with the detection of organics, but perchlorates are probably far more effective, says Chris McKay of Ames. Even if organics make up a few parts per thousand of the soil, Viking or Phoenix could have missed them, he adds, so it is too soon to conclude that these materials are not there. "We haven't looked the right way," he says.

Bonk · « **Reply #1 on:** May 27, 2009, 05:17:56 pm »

Good Lord man. By the sound of it they never validated the method prior to the mission. That just can't be. Can it?

Oh wait, new(pseudo)scientist link alert! Did this come from Slashdot? I wish they'd give up on the pop science link spam and just put a permanent banner ad / link to new(pseudo)scientist.

There's got to be some misunderstanding here. If not, then I'm going to look into the Canadian Mars lander and see what if any analysis plans are in the works. (I should regardless)

This makes a really good case for "outsourcing" in federal projects. Where was Agilent through all this? Or Varian, or Perkin-Elmer, or Thermo, or...

Nemesis · « **Reply #2 on:** May 27, 2009, 05:24:55 pm »

Quote from: Bonk on May 27, 2009, 05:17:56 pm

Good Lord man. By the sound of it they never validated the method prior to the mission. That just can't be. Can it?

As I understood it the issue was the perchlorates were not expected in the soil. That changed the reactions from what they expected and planned for.

Bonk · « **Reply #3 on:** May 27, 2009, 06:01:46 pm »

Quote from: Nemesis on May 27, 2009, 05:24:55 pm

Quote from: Bonk on May 27, 2009, 05:17:56 pm
Good Lord man. By the sound of it they never validated the method prior to the mission. That just can't be. Can it?

As I understood it the issue was the perchlorates were not expected in the soil. That changed the reactions from what they expected and planned for.

I also gathered that. (did not RTFA because of location) Part of good method validation is testing for robustness, where various failures are introduced and the effects on results observed. However, I don't think that would have helped in this case. The problem is design specificity. When I perform analysis of soils for organic components, I don't just shove a fistful of soil into an instrument, there is a lot of pretreatment involved that usually involves very specific techniques for isolation of analytes of interest.

I'm pretty sure with a NASA sized budget I could come up with an automated micro analysis of soils for organics that would be nearly totally independent of the mineral composition of the sample matrix. (as such a method should be)

Like I said, I find it hard to believe. Missing so much information though, I expect the answer is in the technical/financial details that we are missing.

Nemesis · « **Reply #4 on:** May 28, 2009, 07:35:10 am »

I suspect that the design was based on working with what they believed would be present while sending tools of a minimum weight. To perform the extra steps automatically that you would perform personally would likely have made the system too heavy to send. The probe itself weighted 550 KG and the 8 ovens were apparently about the size of a ballpoint pen.

Hopefully now that they have a better understanding of the soil composition a future probe could do "life testing" without the excess heat that caused these tests to fail.

If all else fails a future manned mission would be more flexible in its testing.

knightstorm · « **Reply #5 on:** May 28, 2009, 01:03:19 pm »

Also, keep in mind that the viking probes were built during the time period after the moon race when NASA was losing much of its political support. Its fairly amazing that they were able to accomplish all that they did during that decade, despite the fact that they had to seriously downsize their ambitions, ie. the grand tour of the solar system was reduced to 2 pioneer, and 2 voyager probes, the pioneers sent as cheaper throwaway probes just to make sure that the outer solar system was safe enough to send the more expensive voyagers, The space station/shuttle program was severely downsized to just the shuttle.

Dracho · « **Reply #6 on:** June 04, 2009, 02:57:31 pm »

What knightstorm said.. it takes a decade+ to get a mission like this from the drawing board to the landing site. Anymore, science changes a lot in 10 years.

Nemesis · « **Reply #7 on:** June 04, 2009, 03:39:17 pm »

Viking 1960's tech
Phoenix 1990's tech
Next mission 2000's tech ? ?

It is easy to forget how much underlying technology changes over the decades.

Dracho · « **Reply #8 on:** June 04, 2009, 04:31:53 pm »

Quote from: Nemesis on June 04, 2009, 03:39:17 pm

Viking 1960's tech
Phoenix 1990's tech
Next mission 2000's tech ? ?

It is easy to forget how much underlying technology changes over the decades.

And that tech is provided by the lowest bidder..

News: