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.
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.
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. 🤔🙄
<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.......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.
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...
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.
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.
Quote from: Zed_Noir on 10/21/2023 10:56 amWell 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.QuoteAlso 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.QuoteHopefully 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 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?
Also a big rover might be able to deploy a core drilling rig that can get samples from 5 meters beneath the Martian surface
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.