Life on Mars? It’s a debate that has raged since the late 19th century, when Italian astronomer Giovanni Schiaparelli trained his telescope on the Red Planet and concluded that the canali he saw on its surface were the transport routes of an advanced race. A century later, space enthusiasts claimed to see the face of a helmeted humanoid in space probe images of Mars’ Cydonia region. NASA refuted these claims, and, in response, released an image from its archives of a “happy face” on the Martian surface. There’s also a space shot in the public domain of a Martian landform that resembles Kermit the Frog.

More recent and sharper images of the Cydonia region from the Mars Global Surveyor have revealed the much-ballyhooed structure to be an ordinary hill. From canali, to helmeted humanoids, to today’s astrology charts, it seems the Red Planet has long functioned as a sort of interplanetary Rorschach blot, with observers tracing their fears and hopes in both its orb, and its orbit.

The Cydonia crowd was barking up the wrong terrain. The most compelling evidence of extraterrestrial life – microbial life, that is – may actually have already been found on Mars. On July 20, 1976, after a 10-month journey and a Gulliver-sized leap of 200 million miles from Earth, the first Viking Lander unfolded its spindly legs and touched down on the Martian surface. A burst of cheers erupted in the Jet Propulsion Laboratory in Pasadena, the Viking Mission’s control centre. In a short time, the Viking camera began transmitting a panoramic view of the Martian landscape, and the room went wild. The Red Planet, revered by Babylonians as a “fire star,” and associated with their most feared sky god, had shown its true face.

Six weeks later, Viking Lander 2 set down in a more northerly location. Each Lander contained equipment for the detection of Martian life forms. One experiment examined gas changes inside a small chamber, where a portion of Mars soil was exposed to water vapour and a cocktail of nutrients. Another experiment looked for the synthesis of organic substances in separate Martian soil samples. The third experiment, the “labeled release” experiment, supplied a diluted solution of five nutrients, tagged with radioactive carbon to Martian soil.

The labeled release experiment was the brainchild of Dr. Gilbert V. Levin, who first brought the possibility of testing for life on Mars to the attention of NASA officials back in 1959. Levin, a PhD in environmental engineering, and a former clinical assistant professor of preventive medicine at the Georgetown University school of medicine and dentistry, knew that his invention of microbial radiorespirometry could be adapted for interplanetary missions. In the early ‘60s, he went to work with Hazelton Laboratories Incorporated, where he tinkered with his “extraterrestrial life detection” experiment. He called his invention Gulliver, remembering how Swift’s fictitious character travelled enormous distances and discovered tiny Lilliputian creatures.

Levin’s fascination with Mars dated back to his childhood. As an adult, he would lead his children to the backyard telescope he had bought for them, so they could see Mars for themselves on warm summer nights. Once or twice, they even managed to spot Mars’ bright polar ice caps and dark surface markings. His lifelong fascination with the fourth rock from the sun, and his later stumping for his life detection scheme, eventually paid off. His labeled release experiment, an outgrowth of Gulliver, was chosen as one of three other submissions for the life detection experiments on the Viking mission in the mid ‘70s. Levin gathered a team, which included Dr. Patricia Ann Straat, a young microbiologist from John Hopkins University. The two set to work trying to squeeze the LR equipment into a quarter of a cubic foot, the maximum amount of room available for Levin’s experimental apparatus on each of the two Viking Landers.

Shortly after landing on Mars, Viking 1’s surface sampler arm extended and scooped up a small quantity of material. Retracting into the Lander, the arm then apportioned the sample for testing in the three experiments. On the eighth day of the Viking mission, LR team leader Gilbert Levin got the chance of a lifetime, when his team injected its sample with radioactively tagged nutrients. According to Barry DiGregorio, author of Mars: The Living Planet, the radioactivity was measured every 16 minutes. “By early evening on July 30, it was obvious that a significantly positive reaction was occurring. It looked very similar to the response from Earth soils that contained microorganisms.” It appeared that something was metabolizing the nutrients.

As the LR count rate continued, Levin assigned one of the team to go out and get a bottle of champagne. They had yet to perform a control experiment, but Levin was already confident that life had been discovered on another world.

Over a two-month period on the Viking Mission, Levin and Straat conducted nine experiments. For his control samples, Levin heated the samples to 160 degrees Celsius, to destroy any living material that might be responsible for the observed reaction. When these samples were supplied with radioactively tagged nutrients, there were no reactions, consistent with the organic chemistry interpretation. Levin also discovered that the reactions seemed critically sensitive to a heating between 46 to 51 degrees, the range that might kill living organisms, but which have no effect on most inorganic compounds.
Orthodox NASA scientists viewed the labelled release findings as the result of highly reactive compounds, called superoxides and peroxides. According to Levin and his colleague Patricia Ann Straat, these are entirely theoretical constituents of the Martian soil, for which there is no evidence. He also noted highly reactive chemicals such as these decay in the presence of water, one of the additions to the nutrient.
NASA decided that the evidence for life on Mars was ambiguous, and like most big bureaucracies, erred on the side of conservatism. (That may be the most charitable interpretation of the official response.)
Arguing that their data deserved a better hearing, Levin and Straat carried their battle into the pages of obscure scientific journals, becoming in the process, personae non gratae within mainstream planetary science. Levin received no further invitations to NASA events. The agency even tried to block his efforts to negotiate with Russians to include his LR Experiment on the Mars Polar Lander mission in 1996.

All this begs the question: if the LR experiment indicated a strong possibility for the existence of microorganisms on Mars, why would NASA be so opposed to this interpretation, when the presumed purpose of the Viking Mission was to search for life? One possible reason is that, at the time, reigning theories of exobiology ruled out cold planets with thin atmospheres as potential sources of extraterrestrial life.

The other reason may involve non-scientific belief systems. Levin told author DiGregorio of attending a 1961 meeting on space biology with Dr. Philip H. Abelson, editor of the preeminent journal Science, in which he overheard Abelson say: “The Bible tells us there cannot be any life on other planets – this is a waste of time.” Levin was “shocked” by this, and not surprisingly. DiGregorio noted: “It was under Abelson as editor that Science rejected two of our scientific papers on the possibility of having detected life on Mars.”

Mars: The Living Planet supplies troubling anecdotes suggesting that the fix was in for the Viking Mission from the start. When the first images from Mars arrived at JPL headquarters, they revealed a multicoloured landscape eerily reminiscent of Arizona, complete with a blue sky. NASA staffer Ron Levin (no relation) looked on in amazement as a technician went from monitor to monitor, changing the settings so that the landscape and sky presented a uniformly orange and red appearance. Levin followed the technician, changing the settings back, only to be “chewed out” by James S. Martin Jr., Viking project manager.

Gil Levin later discovered that the order to change the monitor settings came from the top. One can only speculate why NASA wanted the Earth-like scenery twiddled with. (A few colour-true pictures from NASA, which show untouched images of blue skies, are now in circulation in books about Mars.)

In all NASA missions subsequent to Viking, not a single one has carried life detection equipment to settle the debate. Yet, the walls may be cracking. A full 25 years after the Viking Landers first settled down on the Red Planet, Levin’s data got another look. Joseph Miller, PhD, associate professor in the department of cell and neurobiology at the Keck School of Medicine of the University of Southern California, examined the data from the original LR experiments. Miller, who worked with NASA in the ‘80s, did some number crunching. He discovered something in the data that no one else had detected, including Levin and Straat: a highly periodic gas release, characteristic of the metabolism of living organisms. In a university news release from July 2001, Miller announced: “The signal itself not only had a circadian rhythm, but it had a precise circadian rhythm of 24.66 hours – which is particularly significant, because it’s the length of a Martian day.”

“I think back in 1976, the Viking researchers had an excellent reason to believe they’d discovered life,” said Miller. “I’d say it was a good 75 percent certain. Now, with this discovery, I’d say it’s over 90 percent. And I think there are a lot of biologists who would agree with me.”

NASA’s much-ballyhooed “Mars meteorite” from 1996, containing what some scientists consider fossils of microorganisms, evidenced a shift in thinking in the agency, though certainly not seismic in scope. More recent announcements from NASA, concerning the geological formations on Mars, which reveal ancient river channels and lake beds, indicate that many astronomers now favour the hypothesis of a once watery planet. NASA seems less resistant to the idea of microbial life on the Red Planet now than in the ‘70s. Still, a plaque mounted near the Viking Lander exhibit at the Smithsonian National Air and Space Museum holds to the official line on results from the Viking’s life detection experiments: “The biological experiments on the Viking Landers did not detect any positive signs of life or any of the organic compounds that are abundant on earth.”

Geoff Olson