by Barry E. DiGregorio
Middleport - July 16, 2000 - In 1976 the twin Viking Lander spacecraft touched down on the surface of Mars and began the first ever, search for extraterrestrial life. Onboard where three miniaturized biology laboratories each with a unique focus on how to look for microbial life on Mars.
Of the three biology instruments on each Viking Lander, the Labeled Release experiment designed by Dr. Gilbert V. Levin, obtained intriguing results that Levin says is consistent with microbial metabolism.
Levin and his Viking co-experimenter, Dr. Patricia Ann Straat, submitted a number of peer reviewed scientific papers on their findings to prestigious science journals such as ICARUS, SCIENCE, and the JOURNAL OF GEOPHYSICAL RESEARCH.
However, because another instrument aboard the Viking Landers was designed to detect organic molecules and found none on Mars, it was announced publicly by the Viking Project scientist, Dr. Gerald Soffen, that the Viking biology experiments could not have found life.
Soffen is often quoted as having said, "That's the ball game. No organics on Mars, no life on Mars."
The events that unfolded after Soffen's public announcement would eventually alter the coarse of the NASA Mars Exploration program. Instead of focusing on a further search for extant life on Mars, the program was being prepped for the ultimate goal of sending humans and returning Martian soil samples considered sterile, directly to the Earth.
A number of NASA spacecraft have been sent to Mars in the years that intervened since Viking, but none have focused on trying to resolve the important issue of life (See Barry E. DiGregorio's SpaceDaily article "The Need For Mars Mission Exobiologists").
All of the Mars mission science teams since Viking have not had or included any biologists. However, all that may soon change. With the British built Beagle 2 life sciences lander scheduled to touch down on the surface of Mars in 2003 and to specifically look for extant or extinct life, perhaps a new space race will begin - the race to confirm life.
"Confirm" is the word of choice because the Viking Landers already found evidence for Martian life in 1976. There are some scientists that will no doubt say the results were inconclusive, but for how much longer can they say this is the question.
Dr. Levin and Straat put together the scientific argument that the Viking GCMS should not have been used as "the court of appeals" on whether the Viking biology experiments found evidence for life on Mars or not.
In a scientific paper published in 1981, Levin and Straat demonstrated that in pre-flight-to-Mars testing of an Antarctic soil sample (#726), that their Viking Labeled Release experiment found microbial activity in the same sample of soil that was tested by the Viking GCMS.
The tests showed that the pre-flight Viking GCMS test model could not detect organic molecules in Antarctic soil sample that contained life. Yet this would be the instrument used to render the final verdict against any positive evidence of life on Mars that might have been found by the Viking biology instruments.
Strangely enough, one of the other Viking biology instruments known as the Pyrolytic Release experiment found traces of organic matter forming inside its test chamber. This occurred in seven out of nine PR tests.
Oddly enough the NASA scientific community at the time did not consider the matter seriously enough to warrant a full review, and Levin and Straat as a result became labeled as eccentric scientists for pursuing it.
In 1997, Levin made the extraordinary claim in the book "Mars The Living Planet" (in which he wrote a chapter) and simultaneously in a scientific proceedings paper he was asked to present for the Society for Professional Optical Instrumentation Engineers (SPIE).
Levin stated that the Labeled Release experiment on both Viking Landers "detected living organisms" in samples of Martain soils. Prior to this, Levin's strongest statements had been that the results from his Viking biology instrument were consistent with a biological explanation.
However, after years of examining all the non-biological possibilities combined with new knowledge gained about life in extreme environments and Mars, he now felt confident enough to say that his experiment found microbial life on Mars, not the hypothetical chemical oxidants some scientists inferred.
Because Levin had already been branded a scientific eccentric, the majority of the NASA scientific community all but ignored this new claim.
Then in March of 2000, Dr. Steven A. Benner, Professor of Chemistry at the University of Florida, published an important new paper about the sensitivity of the Viking GCMS experiment.
Titled "The Missing Organic Molecules On Mars" (published in the PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES, Vol. 97, p 2425, March 18, 2000), Benner et al., concluded that the Viking GCMS was insensitive to certain organic molecules including those left behind by any microbial life that might have been on Mars.
No longer could the Viking GCMS findings rule out life on Mars. The plaque mounted at the entrance of the Viking Lander exhibit in the National Air and Space Museum reads, "The biological experiments on the Viking Landers did not detect any positive signs of life or any of the organic compounds that are so abundant on the Earth." With Benner's new findings on the shortcomings of the Viking GCMS, would the plaque at the Smithsonian Air and Space Museum need to be rewritten?
Levin who remained steadfast to his claim, has continued to publish scientific papers, with one in 1998 describing how microorganisms can derive their water requirements from brief wetting events that he postulated occurs on the Martian surface.
Since the publication of that paper in an SPIE Proceedings Volume on astrobiology detection methods, several scientific papers by other scientists have been published and support the notion of liquid water on Mars for brief periods of time. The stage seemed set for something new to happen, perhaps a turning of the tables.
A circadian biologist and neuroscientist from Texas Tech University named Joseph Miller says there may be circadian rhythms in Levin and Straat's Viking biology data. Miller says, "Being the compulsive person that I am, I decided to review the Viking biology data.
My concentration was on the Labeled Release experiment, which some believe to be the strongest evidence for Martian biology." The Viking LR graph published in the Journal of Geophysical Research Vol. 82, no. 28, p 4663, 1977 captivated Miller instantly.
Circadian rhythms are cycles within a living organism, that take about 24 hours (on Earth) in order to complete from start to finish. Based on a light-darkness cycle, circadian rhythms are used as an entraining agent by scientists in order to study an organism's rhythm since the length of the cycle can be manipulated under laboratory conditions.
Miller worked with NASA's Space Shuttle Project from 1982 - 1987 and collected information on how orbital spaceflight and weightlessness affected circadian rhythms in monkeys and rats.
But it would not be until April of this year before Miller decided to approach NASA with a proposal to see if the Labeled Release experiment data has evidence of circadian rhythms in it. With the winds of change, NASA approved and offered its cooperation.
What is the next step? Dr. Miller has been gathering all the available archived Viking Labeled Release data from NASA, Levin, and Straat . He would like to obtain 12,000 data points to properly make the case for circadian rhythms in the LR data.
Other obstacles Miller faces in his research are the phase angle and cross correlation of the temperature fluctuations with the LR rhythm. The LR experiment had a built in heating element that kept Martian samples at an ambient temperature to prevent the LR liquid nutrient from freezing.
Miller says if he can exclude temperature effects, then the LR rhythm may be endogenous and the signature of a microbial lifeform. This would greatly add support to Levin's case for life on Mars.
How long before we will know? Miller says that once he has all the data in place it could be only a matter of days. And what if Miller finds there are no circadian rhythms in the LR data, then what? Does it mean the LR did not find any evidence for life on Mars?
According to Dr. Gilbert V. Levin, one way to positively confirm whether the LR instrument found life on Mars is to send a chirality experiment on a future Mars Lander.
"If the experiment detects a preference of one or the other stereoisomers of a chiral compound placed on the Martian soil, this would constitute irrefutable proof of living organisms" Levin said.
This article is copyright Barry E. DiGregorio 2000. Please do not reprint, republish or transmit in any form without the express written permission of SpaceDaily.com or Barry E. DiGregorio 2000.
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