Author Topic: The Labeled Release experiment on the Viking mission  (Read 24405 times)

Offline Jim

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Re: The Labeled Release experiment on the Viking mission
« Reply #40 on: 10/20/2023 01:00 pm »
From a scientific standpoint, they made absolutely zero sense (not lookig for life, but how the Viking experiments were done). These were almost PR stunts.
No one knows what was reacting or why. They knew nothing about the substrate. Anyone who reasonably questioned the experiment with only the knowledge of the time would be able to say they weren't very sound experiments.

And thats WELL before you get into the actual microbiological aspect of the entire thing. The experiment basically assumed there was a gigantic population of healithy dormant microbes just waiting to have sugar water dumped on them.


Completely unknowledgeable post.

Offline Emmettvonbrown

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Re: The Labeled Release experiment on the Viking mission
« Reply #41 on: 10/20/2023 02:05 pm »
The arrogance, too - pretty sickening. Must be a SpaceX "rotating wind machine"-"young men"

Offline deadman1204

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Re: The Labeled Release experiment on the Viking mission
« Reply #42 on: 10/20/2023 02:52 pm »
Everyone knew mars was a dead planet WELL before viking. We found that out in the early 60s.

Otherwise, I invite the board experts (jim, emmetvonbrown and others) here to explain why these were "good science". I know your more comfortable just lobbing insults and disagreements and never backing anything up. Super easy to.
« Last Edit: 10/20/2023 02:54 pm by deadman1204 »

Offline Jim

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Re: The Labeled Release experiment on the Viking mission
« Reply #43 on: 10/20/2023 04:11 pm »
Everyone knew mars was a dead planet WELL before viking. We found that out in the early 60s.

Otherwise, I invite the board experts (jim, emmetvonbrown and others) here to explain why these were "good science". I know your more comfortable just lobbing insults and disagreements and never backing anything up. Super easy to.

Sorry shouldn't have posted that but some posts deserve them .   You made the idiotic claim.  The onus is on you to explain why it wasn't "good science" and who is "everybody".    And tell us how you could have done better, without 20/20 hindsight.  And present your credentials as part of your response.


« Last Edit: 10/20/2023 04:50 pm by Jim »

Offline Phil Stooke

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Re: The Labeled Release experiment on the Viking mission
« Reply #44 on: 10/20/2023 04:31 pm »
"... explain why these were "good science".

What would you have done with the technology of the day?  What they did was the best that could be done at the time, but if you have better ideas we are all eager to hear them.

"Everyone knew mars was a dead planet WELL before viking. We found that out in the early 60s."

Care to elaborate?  The only early 60s mission you can possibly be referring to is Mariner 4 and it showed us that Mars was cold, dry and cratered, but it certainly didn't show us it was dead.  Jim Lovelock's atmospheric chemistry argument was reasonable if that's what you refer to, but it wasn't proof.

Online ccdengr

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Re: The Labeled Release experiment on the Viking mission
« Reply #45 on: 10/20/2023 04:35 pm »
It's easy to find problems with the Viking experiments with 20-20 hindsight, but they did the best they could with very limited information and under severe mission constraints.  Definitely they were designed to find "life as we know it" and could have found terrestrial life easily.  It's not true that all three experiments used water -- the pyrolytic release experiment didn't and operated under purely martian conditions.

"We knew Mars was dead in the 60s" -- umm, no.  We knew it was less earthlike than some had thought after Mariner 4, but we don't know that it's dead even today, do we?

https://en.wikipedia.org/wiki/Viking_lander_biological_experiments and links from there are a pretty good summary of the experiments.

Online zubenelgenubi

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Re: The Labeled Release experiment on the Viking mission
« Reply #46 on: 10/20/2023 06:54 pm »
I remember Bruce Murray stating in his book that some planetary scientists preferred a much better understanding of Martian geology and atmosphere before performing in-situ life detection experiments.

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« Last Edit: 10/20/2023 07:07 pm by zubenelgenubi »
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Offline Dalhousie

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Re: The Labeled Release experiment on the Viking mission
« Reply #47 on: 10/21/2023 01:09 am »
Everyone knew mars was a dead planet WELL before viking. We found that out in the early 60s.

Otherwise, I invite the board experts (jim, emmetvonbrown and others) here to explain why these were "good science". I know your more comfortable just lobbing insults and disagreements and never backing anything up. Super easy to.

You're the one making this claim, so the onus of proof is on you.

First of all who is "everyone" who knew Mars was a dead planet in the early 60s?  Remember this was before the first successful flyby (July 15, 1965) or Lovelock's paper on atmospheric chemistry (August 7, 1965), both quite misleading in many respects.

I have already provided list of good scientists who thought that searching for life on Mars was good science -  Levin, Visniac, Sagan, Rho, Lederberg, Horowitz, Oyama, Biemann, Klein, Soffen.  Note that "good scientists" does not mean they they were right about everything.
Apologies in advance for any lack of civility - it's unintended

Offline Dalhousie

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Re: The Labeled Release experiment on the Viking mission
« Reply #48 on: 10/21/2023 01:23 am »
I remember Bruce Murray stating in his book that some planetary scientists preferred a much better understanding of Martian geology and atmosphere before performing in-situ life detection experiments.

Carl Sagan: Part of the solution?  Or part of the problem?

My opinion: Both. 🤔🙄🫡

Murray was writing from hindsight of course, and at a time prior to the widespread appreciation of extremophiles or post Viking Mars surface data. However he still supported Mars missions to search for life while head of JPL.

Given that both Murray and Sagan founded the Planetary Society and championed planetary exploration and astrobiology through the late 70s and into the 90s, a period where the whole discipline was in the doldrums
Apologies in advance for any lack of civility - it's unintended

Offline Don2

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Re: The Labeled Release experiment on the Viking mission
« Reply #49 on: 10/21/2023 06:55 am »
I think the biology experiments on Viking were over ambitious for their time. Several mistakes were made.

1/ They lacked a foundation of understanding of the chemistry of the surface, which they needed to design life detection experiments. They did not know how abundant organics were on Mars, or if that abundance increased with depth. They did not know how easy the surface material would be to dig and collect samples from. They did not know how the soil would react to being wetted. They didn't know what the soluble components were, and what types of solutions would form when water was in contact with the soil. They should have started with a smaller, cheaper lander which was focused on understanding the chemistry. The first experiments should have been a GCMS and a wet chemistry experiment similar to what flew on the Phoenix lander. That was the experiment which discovered the perchlorate.

2/ The GCMS team on Viking reported that they did not detect organics. However, that wasn't true. They did detect low levels of chlorinated organics, but those were so unexpected that they concluded that they couldn't possibly be Martian. Chlorinated organics are never produced naturally and are the product of human industry....or so they thought in the 1970s. What they lacked was a robust control experiment that could have proven that those completely unexpected compounds were native to Mars.

3/ There were no follow up missions to investigate the questions raised by the Viking experiments until the Phoenix lander arrived over 30 years later. To this day we still don't know how the soil chemistry varies with depth.

A better strategy would have been to start with a basic, chemistry focused lander. Then follow that up with a more elaborate lander a decade later which would build on the results of the first and do biological experiments.

Offline Star One

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Re: The Labeled Release experiment on the Viking mission
« Reply #50 on: 10/21/2023 09:42 am »
We don’t even know if Mars is a dead planet or not now, let alone the 1960s.

Offline Zed_Noir

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Re: The Labeled Release experiment on the Viking mission
« Reply #51 on: 10/21/2023 10:56 am »
<snip>
A better strategy would have been to start with a basic, chemistry focused lander. Then follow that up with a more elaborate lander a decade later which would build on the results of the first and do biological experiments.
Well NASA/JPL got sidetracked with a series of rovers that is mostly for optical and spot surface geology investigations away from a static site.

Also the lander and/or rover that lands on Mars retains the limitations of the Viking EDL (entry, descend & landing) method in payload mass & volume available. Which make chemistry investigations harder and more expensive. AIUI NASA is still using the same Mars EDL method for future Martian landers and/or rovers. That means getting core samples no deeper than a few cm below the Martian surface.

Hopefully in the future there will be bigger Martian landers that can deploy larger rovers capable of more investigations in chemistry and biochemistry deep beneath the Martian surface.

Offline Don2

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Re: The Labeled Release experiment on the Viking mission
« Reply #52 on: 10/21/2023 04:55 pm »
Well NASA/JPL got sidetracked with a series of rovers that is mostly for optical and spot surface geology investigations away from a static site...
.
...Hopefully in the future there will be bigger Martian landers that can deploy larger rovers capable of more investigations in chemistry and biochemistry deep beneath the Martian surface.

The rovers have not been a sidetrack. Curiosity has revolutionized the understanding of Martian organics. Viking detected about 100 parts per billion of chlorinated organics. Curiosity has detected several hundred parts per million of carbon, including single and double ring compounds and macromolecules like kerogen. The long term plan is to solve all the problems with sample return, if it is affordable. If the initial experiments on a returned sample produce confusing results like the Viking experiments did, then new experiments can be devised to resolve the confusion.

There is going to be a presentation on Martian organics at the next AGU meeting. The session abstract says:
Quote
Our understanding of organic matter on Mars has evolved from presumed ‘missing organic molecules’ based on Viking data to a robust library of organic molecules detected over the last decade by the SAM (Sample Analysis at Mars) instrument suite onboard the Mars Science Laboratory (MSL) rover .....

...MSL detections of organics in Gale crater mudstone and sandstones include chlorohydrocarbons up to 300 ppbw; small aliphatic, aromatic, and, sulfur-containing compounds (at 0.1-10 ppmw detections) potentially originating from macromolecular organics and long-chain alkanes from C10 to C12. Total abundance of C is likely higher than individual molecular detections and on the order of 100’s of ppmw. The recent TMAH wet chemistry experiment liberated macromolecular organics, resulting in the detection of one to two-ring aromatic compounds, benzoic acid methyl ester, and benzothiophene. All these detections confirmed the presence of organics in the Martian subsurface, despite exposure to ionizing radiation for at least 80 My...
https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1268725

The Exomars rover has a drill capable of going down 2m, so that could explore the vertical distribution of organic compounds, if it ever flies.

Offline Dalhousie

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Re: The Labeled Release experiment on the Viking mission
« Reply #53 on: 10/22/2023 01:13 am »
I think the biology experiments on Viking were over ambitious for their time. Several mistakes were made.

Agreed, but that is hindsight.  The biology experiments date back to the early 602 and Mariner B.  They were also a prime focus of of these missions. 

Quote
1/ They lacked a foundation of understanding of the chemistry of the surface, which they needed to design life detection experiments. They did not know how abundant organics were on Mars, or if that abundance increased with depth. They did not know how easy the surface material would be to dig and collect samples from. They did not know how the soil would react to being wetted. They didn't know what the soluble components were, and what types of solutions would form when water was in contact with the soil. They should have started with a smaller, cheaper lander which was focused on understanding the chemistry. The first experiments should have been a GCMS and a wet chemistry experiment similar to what flew on the Phoenix lander. That was the experiment which discovered the perchlorate.

Again, hindsight and the limitations of the biology team which included excellent lab biologists, chemists and instrumentation engineers, but limited field microbiology or soil science expertise. GCMS was envisaged from the start with Mariner B.

3/ There were no follow up missions to investigate the questions raised by the Viking experiments until the Phoenix lander arrived over 30 years later. To this day we still don't know how the soil chemistry varies with depth.

A better strategy would have been to start with a basic, chemistry focused lander. Then follow that up with a more elaborate lander a decade later which would build on the results of the first and do biological experiments.
[/quote]

Keep in mind that remote geoscience instrumentation was very limited at the time.  We can look at 60's landers for what was available.  Penetrometers measuring soil strength, alpha backscatter and gamma spectrometers for very basic composition, gamma ray densiometers.  None of this data would have helped better interpret the Viking data and would have been inferior to Viking's XRF system.

Some sort of wet soil chemistry lab might have been possible on Viking, and at the expense of other instruments.  Which would you throw out?  I don't think that sort of very detailed soil behaviour analysis would have been deemed appropriate for initial missions, even if the technology was available.
Apologies in advance for any lack of civility - it's unintended

Offline Dalhousie

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Re: The Labeled Release experiment on the Viking mission
« Reply #54 on: 10/22/2023 01:42 am »
Well NASA/JPL got sidetracked with a series of rovers that is mostly for optical and spot surface geology investigations away from a static site.

I don't think rovers were a side-track.  Even during Viking people saw the need for mobility as landers always come down somewhere safe (i.e. boring), away from the best features.  Viking showed the need for better understanding of the martian surface, those rovers have done that.

Quote
Also the lander and/or rover that lands on Mars retains the limitations of the Viking EDL (entry, descend & landing) method in payload mass & volume available. Which make chemistry investigations harder and more expensive. AIUI NASA is still using the same Mars EDL method for future Martian landers and/or rovers. That means getting core samples no deeper than a few cm below the Martian surface.

EDL technology limits do not preclude fairly sophisticated onboard analysis, as shown by Viking (the like experiments, XRF, GCMS), Phoenix (MECA, TEGA), Curiosity (SAM), and Rosalind (Pasteur).  It does preclude the number of such instruments that can be carried, however.  It does not preclude drilling either, witness Rosalind's 2 m drill.

Quote
Hopefully in the future there will be bigger Martian landers that can deploy larger rovers capable of more investigations in chemistry and biochemistry deep beneath the Martian surface. 

Maybe, though remember that costs tend to go up exponentially with size, the great the complexity of the instruments and the sample preparation the greater the chance of things going wrong, as we have seen with Viking, Phoenix, and Insight.
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Offline Zed_Noir

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Re: The Labeled Release experiment on the Viking mission
« Reply #55 on: 10/22/2023 10:39 am »
Well NASA/JPL got sidetracked with a series of rovers that is mostly for optical and spot surface geology investigations away from a static site.

I don't think rovers were a side-track.  Even during Viking people saw the need for mobility as landers always come down somewhere safe (i.e. boring), away from the best features.  Viking showed the need for better understanding of the martian surface, those rovers have done that.

Quote
Also the lander and/or rover that lands on Mars retains the limitations of the Viking EDL (entry, descend & landing) method in payload mass & volume available. Which make chemistry investigations harder and more expensive. AIUI NASA is still using the same Mars EDL method for future Martian landers and/or rovers. That means getting core samples no deeper than a few cm below the Martian surface.

EDL technology limits do not preclude fairly sophisticated onboard analysis, as shown by Viking (the like experiments, XRF, GCMS), Phoenix (MECA, TEGA), Curiosity (SAM), and Rosalind (Pasteur).  It does preclude the number of such instruments that can be carried, however.  It does not preclude drilling either, witness Rosalind's 2 m drill.

Quote
Hopefully in the future there will be bigger Martian landers that can deploy larger rovers capable of more investigations in chemistry and biochemistry deep beneath the Martian surface. 

Maybe, though remember that costs tend to go up exponentially with size, the great the complexity of the instruments and the sample preparation the greater the chance of things going wrong, as we have seen with Viking, Phoenix, and Insight.
IMO. The historical Mars rover series was a sidetrack for biochemistry investigations until the Curiosity rover.

As you stated the current Martian EDL method limited the volume of instruments that can be put in a lander and/or a rover for a mission.

As for the Rosalind 2 m drill. AIUI that was with the Roselind aboard a Russian lander. Can ESA still put a 2 m drill with Rosalind rover landing aboard a NASA lander?

I may be mistaken, there are costs to miniaturized instruments for mass consideration in development and manufacturing for a spacecraft/lander/rover. That is to say a bigger lander or rover don't have to miniaturized instruments as much. Reducing complexity.

Also a big rover might be able to deploy a core drilling rig that can get samples from 5 meters beneath the Martian surface
.

Offline Dalhousie

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Re: The Labeled Release experiment on the Viking mission
« Reply #56 on: 10/22/2023 11:28 pm »
IMO. The historical Mars rover series was a sidetrack for biochemistry investigations until the Curiosity rover.


I would not say it was a sidetrack, but rather a hiatus until the nature of the martian surface was better constrained WRT physical properties, chemistry, and mineralogy.  As others have here pointed out, with hindsight, such knowledge may have better constrained experimental and instrument design, which they have done, although there were still unpleasant surprises with Phoenix, Curiosity, and Insight.

Quote
As for the Rosalind 2 m drill. AIUI that was with the Roselind aboard a Russian lander. Can ESA still put a 2 m drill with Rosalind rover landing aboard a NASA lander?

Good question (which means I don’t have an answer).  Until I read anything to the contrary, I will assume that modifications will be minimal.  I have not read anything on the actual new lander specs, have you?

[/quote]I may be mistaken, there are costs to miniaturized instruments for mass consideration in development and manufacturing for a spacecraft/lander/rover. That is to say a bigger lander or rover don't have to miniaturized instruments as much. Reducing complexity. [/quote]

Maybe, but remember that many the instruments will still be miniaturised and of course automated compared with their terrestrial counterparts.  So still not cheap.  The more instruments the more time will probably be spent at each site (depending on instrument) therefore fewer sites might be examined overall. There is a trade off.  I suspect Rosalind will cover less ground on Mars than the NASA ones, but we’ll see (assuming it gets there).

Quote
Also a big rover might be able to deploy a core drilling rig that can get samples from 5 meters beneath the Martian surface

Realistically that drilling on Mars will slow, and robotic drilling more than a few cm has a high failure rate, historically (only one of the three Luna deep drilling reached the full depth, Chang’e 5 recovered ~1.5 m out of the target 2.0 m, and don’t forget Insight’s mole fiasco).  This is why Rosalind carries 3 drill stems, with the ability to ditch those that get jammed in the ground.

Drilling provides data on vertical variation, at a high technological cost.  There are easier ways to get much of the information in many cases – by shallow trenching (with robotic arms or even rover wheels), use of natural exposures, etc. 

Are you familiar with the Icebreaker mission proposal?  It seems to be dead in the water, but I thought it was a good way to approach the challenge.

However, we have digressed greatly from the Viking LR experiment, so I will leave it at that.  Happy to chat privately further on possible Mars missions.
Apologies in advance for any lack of civility - it's unintended

Offline Don2

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Re: The Labeled Release experiment on the Viking mission
« Reply #57 on: 10/23/2023 10:49 pm »
Some sort of wet soil chemistry lab might have been possible on Viking, and at the expense of other instruments.  Which would you throw out?  I don't think that sort of very detailed soil behaviour analysis would have been deemed appropriate for initial missions, even if the technology was available.

Understanding the types of solutions formed when water comes into contact with Martian soil is fundamental to interpreting the results of any experiment that involves wet processing. It also has biological implications. Biochemistry always happens in aqueous solution and pH and solute concentration are really important to biology. There are reasons why acid curdles milk, why salt is added to food to preserve it, or why domestic bleach (sodium hypochlorite dissolved in water) kills microbes. If Martian soil formed very acidic/alkaline solutions, or solutions containing powerful oxidizing agents, then that would affect both chemistry and biochemistry.

The gas exchange experiment on Viking showed that Martian soil releases oxygen when exposed to water vapor. I don't think they have ever explained that result. I suppose the current strategy to follow up on that result is to return a sample.

All my comments about the Viking life experiments would also apply to any Europa lander that does astrobiology. The chemistry of the Europa surface is poorly known. Some of the things that are suspected, like sulfuric acid and hydrogen peroxide, are likely to destroy organic molecules, especially if heated.

Offline Dalhousie

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Re: The Labeled Release experiment on the Viking mission
« Reply #58 on: 10/24/2023 05:37 am »

Understanding the types of solutions formed when water comes into contact with Martian soil is fundamental to interpreting the results of any experiment that involves wet processing. It also has biological implications. Biochemistry always happens in aqueous solution and pH and solute concentration are really important to biology. There are reasons why acid curdles milk, why salt is added to food to preserve it, or why domestic bleach (sodium hypochlorite dissolved in water) kills microbes. If Martian soil formed very acidic/alkaline solutions, or solutions containing powerful oxidizing agents, then that would affect both chemistry and biochemistry.

The gas exchange experiment on Viking showed that Martian soil releases oxygen when exposed to water vapor. I don't think they have ever explained that result. I suppose the current strategy to follow up on that result is to return a sample.


It's been done.  Radiation damaged perchlorate duplicates the results of the Viking biology experiments quite well - and the GCMS.

https://phys.org/news/2013-11-habitable-mars-view-viking.html

https://www.lpi.usra.edu/meetings/lpsc2013/pdf/2664.pdf

Apologies in advance for any lack of civility - it's unintended

Offline Emmettvonbrown

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Re: The Labeled Release experiment on the Viking mission
« Reply #59 on: 10/24/2023 06:08 am »
What is interesting too is Biemann take on the matter - in 1978 and near the end of his life: since he lived long enough to heard about that perchlorate thing : he died in 2016.

https://en.wikipedia.org/wiki/Klaus_Biemann

When he made his conclusions in 1978 he wasn't that far off the mark (with 20/20, 100% hindsight of course !).
I mean, he had the correct intuition: that some solvant inside his instrument ovens had destroyed the organics when actually looking at them - and quite logically brought a negative result.
He just got the "hot solvant" wrong. He suggested it was NASA chemicals used to sterilize the ovens. Not quite: it was from Mars itself: perchlorates...   :o

Biemann himself had a interesting debate with other scientists, related to perchlorates and his instrument. Must have been fascinating to get new results after 30 years (1978 - 2008) but also perhaps a little painful.

https://www.google.com/search?q="klaus+biemann""perchlorates"

[zubenelgenubi: Wow! Very overly-long search thread truncated.]
« Last Edit: 10/25/2023 12:01 am by zubenelgenubi »

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