Phys.org is reporting on a recent paper from the journal Astrobiology.
Viking LR experimentors Gilbert Levin and Patricia Straat are trying to determine whether the experiment actually identified life on Mars or not.
From the Phys.Org article:
In 1976, two Viking landers became the first US spacecraft from Earth to touch down on Mars. They took the first high-resolution images of the planet, surveyed the planet's geographical features, and analyzed the geological composition of the atmosphere and surface. Perhaps most intriguingly, they also performed experiments that searched for signs of microbial life in Martian soil.
Overall, these life-detection experiments produced surprising and contradictory results. One experiment, the Labeled Release (LR) experiment, showed that the Martian soil tested positive for metabolism—a sign that, on Earth, would almost certainly suggest the presence of life. However, a related experiment found no trace of organic material, suggesting the absence of life. With no organic substances, what could be, or seem to be, metabolizing?
[...] In the LR experiment, both the Viking 1 and Viking 2 landers collected samples of Martian soil, injected them with a drop of dilute nutrient solution, and then monitored the air above the soil for signs of metabolic byproducts. Since the nutrients were tagged with radioactive carbon-14, if microorganisms in the soil metabolized the nutrients, they would be expected to produce radioactive byproducts, such as radioactive carbon dioxide or methane.
[...] Ever since the LR experiments, researchers have been searching for other kinds of nonbiological chemicals that might produce identical results.
In their new paper, Levin and Straat review some of these proposals. One possible candidate is formate, which is a component of formic acid found naturally on Earth. A 2003 LR-type experiment found that formate in a soil sample from the Atacama Desert in South America produced a positive result, even though the soil contained virtually no microorganisms. However, the study did not include a sterilization control, and it's likely that the formate concentration in the Atacama Desert is much higher than that on Mars.
Another potential candidate is perchlorate or one of its breakdown products. In 2009, the Phoenix mission to Mars detected perchlorates in the Martian soil. Although perchlorates could yield a positive result because they produce gas when interacting with some amino acids, they do not break down at 160 °C, and so would continue to give positive results after the sterilization control.
(Score: 0) by Anonymous Coward on Monday October 24 2016, @02:12AM
So US also has spacecrafts not from Earth... interesting. :P
As for landing, many others "crashed" first, and one even stood alive for over 10 seconds. https://en.wikipedia.org/wiki/List_of_missions_to_Mars [wikipedia.org] Awesome that with such new, for their time, systems we launched and managed to get near or hit with so many. Now we should have better tech (maybe we don't really do) and launch and land with even more, but have weaker will. I guess old Cold War had it's nice side.
(Score: 2) by takyon on Monday October 24 2016, @03:34AM
Luckily the Schiaparelli lander was mostly just a test for a future lander.
[SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
(Score: 0) by Anonymous Coward on Monday October 24 2016, @03:59AM
ESA should call them crashers or impacters. Then fail at it.
(Score: 0) by Anonymous Coward on Monday October 24 2016, @08:25AM
Yeah sure, because NASA never lost a Mars probe …
(Score: 2) by VLM on Monday October 24 2016, @12:46PM
"lithobraking technology demonstrator"
Mars sucks. Too much atmosphere screws up forward facing rocket engines and too little atmosphere to get away with aerobraking and parachutes like on the earth. Should terraform the damn place by comet bombardment to build up the atmosphere or install space elevator tethers first, then send down the people and the bots.
"Phobos Anchored Space Elevator" sounds about right.
(Score: 0) by Anonymous Coward on Monday October 24 2016, @04:30AM
https://en.wikipedia.org/wiki/-oate [wikipedia.org]
(Score: 2) by wonkey_monkey on Monday October 24 2016, @07:59AM
What?
systemd is Roko's Basilisk
(Score: 3, Interesting) by tangomargarine on Monday October 24 2016, @02:51PM
Maybe he's saying that formate and perchlorate should actually be formoate and perchloroate? Not sure...
*squints at Wikipedia articles, trying to remember 7th grade science*
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 0) by Anonymous Coward on Monday October 24 2016, @07:31PM
I was saying that the test is apparently for carboxyl groups, rather than life.
(Score: 2) by tangomargarine on Wednesday October 26 2016, @02:05PM
Which I'm sure no scientist has ever theorized is correlated with life...
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1, Insightful) by Anonymous Coward on Monday October 24 2016, @06:42AM
Seems it would be hard to rule out unknown soil chemistry with just about any chemistry based test.
Triangulation of multiple techniques, or direct microscopic observation, will probably be needed to rule out tricky chemistry.
(Score: 2, Insightful) by Anonymous Coward on Monday October 24 2016, @12:18PM
Did anyone else read the headline and at first think "what, the Vikings already did Mars experiments?"
(Score: 2) by VLM on Monday October 24 2016, @12:37PM
They did discover life in Canada. GD illegal alien Danes pouring across the border in 1000 AD just to get that glorious free Canadian health care. Probably rioted to get the local shops to stop selling poutine and sell lutefisk instead.
(Score: 2) by jcross on Monday October 24 2016, @02:20PM
Yep.
(Score: 2) by tangomargarine on Monday October 24 2016, @02:45PM
Wasn't my first interpretation, but yeah.
Seems like I keep running into sentences lately of the "Time flies like an arrow; fruit flies like a banana" form that require me to go back and reparse it to figure out what the verb is. Sometimes zealous comma use helps. Or in this case, maybe italicize "Viking?"
Whether to quote or italicize book/article/magazine titles is another one of those arbitrary rules I'd have to look up.
"Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
(Score: 1) by Kenny Blankenship on Wednesday October 26 2016, @12:49AM
n/t
Someday, even Killer Meteors must fail.