Destination Mars

by Rod Pyle

  But in a similar experiment performed after Phoenix confirmed perchlorate in Martian soil, which was still in doubt during the Viking era, organics were observed using similar instrumentation and interpreted with the foreknowledge of perchlorate in the soil. “Contrary to thirty years of perceived wisdom, Viking did detect organic materials on Mars,” McKay said upon reviewing the results.1 “It was only by having it pushed on us by Phoenix where we had no alternative but to conclude that there was perchlorate in the soil…. Once you realize it's there, then everything makes sense.”

  This conclusion is based, as mentioned, on the evidence of perchlorate in the soil. With perchlorate present, small amounts of organics could have been present on the Viking samples, but would have been destroyed in the heating process.

  To strengthen the case, and this was the clincher, McKay and co-researcher Dr. Rafael Navarro-González reexamined the chemical results of the Viking experiments. Elements released from the pyrolitic experiment (the gas-chromatograph examination of gasses released by the baking of a soil sample) had shown traces of chemicals that were dismissed by the researchers of the time as Earth-based contaminants, that is, things carried up from Earth aboard the lander, despite the extensive efforts at sterilization. But when McKay and Navarro-González compared the Viking charts to those generated by their Atacama soil experiment, the results were almost identical. It appeared that there had been traces of organic carbon in the Viking sample after all.

  Note that the discovery of organics does not mean life, but the organic building blocks of life. Still, this was a major finding, and for the “evidence of life” camp in the three-decade Viking life-science result discussion, welcome news. More answers should be provided by the MSL mission when it arrives at Mars in 2012.

  McKay and many others have also studied the dry lake valleys in Antarctica. These odd regions, located on the coldest continent in the world, are also the very driest. Rainfall is almost unknown (true rain is estimated to have last fallen in the region about fifteen million years ago), and what moisture is deposited is rapidly depleted by the fierce katabatic (gravity-fed) winds that hurl themselves off the nearby slopes at up to 200 mph.2 Add to this an average temperature of 4°F, and you have a rather similar environment to Mars in many important ways.

  There are also lakes in this exotic region, covered with a thin sheet of ice year-round. They are highly alkaline and ten times as salty as the open sea. These traits make them somewhat akin to the water found on Mars in the distant past. But it is the dry areas that fascinate the Mars crowd. Life is highly challenged in the dry valleys; there is no vegetation and no major life-forms anywhere to be found. Life, where it can be discerned, hangs on tenaciously by a thin thread. But life finds a way, and life there is: In the lakes, mats of algae can be found. Bacteria, yeast, and varied fungi can be found in the nearby soil. The most advanced life takes the form of nematodes, tiny worms.

  What fascinates people like McKay is the phenomenon of eternal permafrost. Large regions of the Canadian Arctic and other similar regions are made up of permafrost, but it melts in the summer season, changing chemistry and soil dynamics. The dry valleys, however, consist primarily of rock and soil over ice which never thaws—much like a lot of Mars. This has proved to be an ideal environment for a number of research projects.

  Some of these projects are mechanical in nature. As the soil is so Mars-like, prototypes for drills and scoops, destined to fly on Mars probes, are tested here regularly. The sampling system for the Mars Phoenix was tested here. Peter Smith, the head of that program at the University of Arizona, was struck by the similarity between this region and the Red Planet. “Those upper valleys are the best analog for the Phoenix site,” he has stated. “The soil temperatures are always well below freezing, ice is stable about fifteen inches below the surface, and the extreme conditions challenge life-forms to the maximum. This is as close as we can get to Martian conditions.”3 The wet chemistry lab for Phoenix was also put through its paces here, a valuable simulation for the harsh conditions found near the Martian poles.

  The drill for the MSL rover was tested in the dry valleys; it's a percussion drill that pounds the soil as it drills into it in order the get the greatest bang for the (weight) buck possible. This kind of testing is more challenging than it sounds. Deep in the hills, far from the nearest bit of civilization, teams must operate the drills while generating their own power and carrying spare parts. Everything must be helicoptered in—and out—including human waste. And the particulars of the drill must be carefully measured: allow the bit to get too hot, and it will melt the very ice it is attempting to sample. Allow the ice being drilled to refreeze, and that's the end of the drill bit, and the sample.

  Beyond mechanical testing though, is the presence of microbes and bacteria in the soil. This dirt is infused with perchlorate, much like the soil of Mars has demonstrated itself to be. Besides being a traditionally toxic blend for earthly organisms, perchlorate also acts as an antifreeze, changing the freezing point of any water that might be found. And perchlorate has also been found to support some kinds of microbial life; anything learned about that relationship can help scientists like McKay understand how life might exist—even thrive in a penurious way—on Mars.

  And these colonies of microbial life—some estimated to be thousands of years old—exist well below the bleached surface. Add to this the existence of hypersaline water that can resist freezing, even in Martian temperatures, and you have an ideal laboratory for Martian life-science simulation.

  Even the small lakes provide a test bed; it is theorized that in some regions of Mars, similar conditions exist where ice overlaying salty water could keep that liquid from freezing. In the dry valleys, even when it is below 0°F, the water beneath the icy surface of the lake is routinely at 32° or higher. This condition, if it exists on Mars, is one more factor in providing an environment where life could exist even today. The ice also traps gasses in the water, and as much as 300 percent more oxygen and 160 percent more nitrogen have been found in the dry valley lakes than the surrounding environment. Again, if this holds true on Mars, the possibilities for life, past or present, look better and better.

  Exploring the parts of Earth that mimic, in some way, Mars is a cost-effective and achievable way to learn much about future explorations of the Red Planet. Thankfully, a few intrepid individuals have paved the way and shown us that such programs and research can pay off. Here's to the Earth-bound Martians.

  A small and select group form the core of the Mars analog explorers. More join this elite cadre every year. What they have in common is a driving curiosity, a sense of adventure, and the burning desire to experience, in some form, Mars.

  ROBERT MANNING, JPL1

  Rob Manning, whom we met during his involvement with Mars Pathfinder, is such a person. While not a pioneer in Mars analog work, he made the journey from JPL to the wilds of Washington State to experience firsthand some of the challenges that would be facing his tiny Pathfinder spacecraft once it reached Mars.

  “[We] wanted to go to what we call a ‘grab-bag' site on Mars, where there were lots of different kinds of rocks, that we could use the nose at the end of the rover, of the APXS, and they selected our area, which was an outflow channel just south of the equator. It's a large chaotic area, where water had popped out of the ground due to reasons which at the time were not clear, and raced down this valley, carving these catastrophic flows at the mouth of Ares Vallis. You can see, even from space, what appears to be water flow channels, and sandbars; it's fantastic.”

  After scrutinizing satellite photos and conferring with the geological team, an Earth analog gradually emerged for testing of the Sojourner rover.

  “So we went to Moses Lake, Washington. It turns out that about fifteen thousand years ago, there was a giant lake in Missoula, Montana, which was stopped up by a giant iceberg. One day it broke, and it sent a cascade of water about fifty feet high, maybe miles across, racing across Washington, the Co
lumbia River, and all the way back to the ocean, and down to Salem, Oregon.

  “There are rocks from Montana, which you can still find, down in North Central Oregon, that were carried down there. These flowed in a catastrophic flood that scoured away the land, and of course this event was huge on Earth, but it was actually much smaller than what happened on Mars, so we did a fantastic field trip that I will never forget. We went all the way around Washington, with some of the top geologists; we talked about our rovers, airbags, rock distributions, how we could test the airbags on Pathfinder.

  “We brought a little rover, it's a little rubber-wheel rover, and we tried driving on the terrain to see how it would work on different rock distributions and types. It was just like we thought the rock's density and distribution would be at our landing site on Mars. There had been a brushfire, so there was no brush around, just charred earth and dirt and rock, and it looked much like Mars except for its darker color. We also brought our lander structure to assemble on the ground to see what its orientation might be on those kinds of rocks once it set down. We wanted to get a feel for what we might be dealing with eventually. It was all very, very helpful.”

  The trip was a resounding success. The lessons learned from driving across the rock fields of Washington and Oregon were of great benefit when planning traverses on Mars and continued, along with other field simulations, to inform during the later missions of the Mars Exploration Rovers. And all this leads up to the granddaddy of rover mission, the Mars Science Laboratory. Rob Manning will be there….

  DR. CHRIS MCKAY, NASA AMES RESEARCH CENTER2

  When peering into the annals of earthly Mars analogs, the name Chris McKay surfaces again and again—as one might expect, for he has done as much of the work as, and more than, almost anyone. How he came to this work, and this passion, is by now a familiar story.

  “I was interested in physics and astronomy as an undergraduate. It was the Viking results in 1976—my first year of graduate school—that sparked my interest in Mars. Then, in 1980, I had the opportunity to be part of NASA's first group of planetary-biology interns. I worked at NASA Ames for the summer and met Imre Friedmann, who was then at Florida State University. Later that year, I went to Antarctica with him, and this cemented my interest in fieldwork related to astrobiology.

  “My main interest in science is the search for a second genesis of life. Extremophiles, organisms living in extreme environments, are of interest because they show the limits of life. To explore this, we've gone to many places in the world where life is in dry or cold, or dry and cold. So lots of deserts, alpine, and polar regions. Different from all the others was an expedition into the Crystal Cave in Mexico, where we were testing an instrument for noninvasive organic analysis.”

  The trip to Crystal Cave was a harrowing one. Deep inside Mexico's Naica Mountain, the cavern is a place of razor-sharp rocks, yawning crevasses, and boiling hot water and steam. It is not a place for the faint of heart…but then again, neither is Mars. Sitting astride huge fault lines, the caves rest atop a huge magma chamber over a mile below. Hot metal-rich fluids circulate through the fault cracks and the cave itself. One chamber, discovered by miners in 2000, is huge, sporting enormous gypsum crystals far larger than anything found in nature and looking like something out of a Jules Verne fantasy. It is also filled with hot gasses, over 120°F, that are deadly.

  Chris McKay traveled there with a team of scientists in 2007. Wielding a spectrometer, he was able to search for organic substances within the giant crystals. The results would inform research scheduled by the MSL mission launched in November 2011.

  “The work in Crystal Cave was to test an instrument for noncontact detection of organics. By ‘noncontact' I mean several meters away. On Mars we want to be able to point our laser at a rock and determine if it has organics. If it does, we might then go to the effort to command the rover to go get the rock and do further analysis on it.”

  But it is the truly extreme environments—the Atacama and the Antarctic—that continue to draw McKay away from the comforts of home: “The Atacama and the Antarctic work remain the most rewarding both in terms of science and in terms of persistent and broad interest on my part. I work in these locations longer and more persistently than anywhere else. The main goal of our work is to understand how life survives in Mars-like conditions and how evidence for life is preserved in Mars-like conditions. How this translates into activities in the field varies considerably from site to site and from year to year. One year in the Atacama we may be focused on how cyanobacteria survive in the dry limit [how dry an environment can be and still support some form of life]. The dry limit for most desert life is crossed in the Atacama Desert. Research results show that the Atacama Desert soils were ‘Mars-like’; meaning that they had very low organics, very low DNA, and no culturable microorganisms, as well as the presence of a non-biological oxidant [perchlorate]. [We have used] Atacama soils as a surrogate for Mars soil in a test of the Viking [experiments] and the effects of perchlorate. Results of this research show that the perchlorate discovered on Mars by the Phoenix mission explains the lack of detection of organics in the Viking mission.”

  Then the next year might be in Antarctica.

  “We are focusing on the high elevations of the Antarctic dry valleys. In particular, University Valley at 1,700 meters [about 5,500 feet] and the nearby valleys. These valleys are so cold and dry that they are the only place we know of on Earth that has ‘dry permafrost.’ Everywhere in the Arctic and most of the Antarctic, the top of the permafrost melts in the summer, forming what is known as an ‘active layer.’ This is the depth to which [a] melting and wet condition penetrates in the summer. In University Valley we find ice-cemented ground that is from a few centimeters to forty centimeters deep [about 1.3 feet], and it never forms a bulk liquid phase. In simple terms, it never melts. For all intents and purposes, the only forms of [water] we have in University Valley are ice and vapor—just like Mars. Our project here is to develop a drill that can work in these Mars-like conditions and to investigate the physics and microbiology of this Mars-like dry permafrost environment.”

  Ice and rock drills for missions like the Mars Science Laboratory and beyond benefit from this research, and it is ongoing.

  Like Indiana Jones, McKay roams the world looking for new adventures and seeking the truth. But unlike that fictional swashbuckler, his mind is forever in the skies…on a frosty red planet named Mars.

  DR. ROBERT ZUBRIN, PIONEER ASTRONAUTICS AND THE MARS SOCIETY3

  Robert Zubrin has been described as a renegade and a visionary. His overriding characteristic seems to be that he tells it like it is—he says what he really thinks, not what is politically expedient or convenient. And what he is trying to tell us, those who will listen, is that it's time to head off to Mars. Long impatient with US efforts in this direction, he was a founding member of the effort to create the Flashline Station simulation of a Mars mission on Earth. He also wrote a bestselling book about a possible future for crewed Mars-exploration efforts, The Case for Mars, and it galvanized his efforts.

  “The book was very successful, sold one hundred thousand copies, and is currently in its sixteenth printing. I got four thousand letters, and they came from all over the world—just a remarkable number of people. Astronauts, people from JPL, twelve-year-old kids from Poland, an incredible assortment of people wrote these letters. I looked at this and I talked with Chris McKay about it, and I said, look at this, look at all these people. They're all saying the same thing…ultimately what they're saying is: How do we make this happen? I thought if we put these people together and form an organization, we'd have a force that might be able to make it happen.

  “So I used the list of the people who sent me letters as a mailing list, and we announced an annual convention of the Mars Society. That first year, seven hundred people showed up, and they came from all over the US and over the world, so we formed the Mars Society that way. We then decided we would do three forms of act
ivity. One was general public outreach, just to spread the faith. The second would be political work, and the third, a project of our own to build a Mars-analog research station.”

  Such a simple thing to say, but much more difficult—and at times harrowing—to do. Money had to be raised; a location had to be selected. Once the site was decided upon, the station had to be designed and prefabricated. This accomplished, it would have to be flown—in pieces—to the Arctic and reassembled there. The story is very complex, and is wonderfully covered in Zubrin's book. Suffice it to say that the task was completed, not once but twice (the second station is in Utah), and the results speak for themselves. After years of unflagging effort, Mars now exists on Earth.

  “What we're into is not so much the field science itself, but something about the exploration process. Besides the Arctic location, we have a separate station in the Utah desert…we take a crew, it's usually six people, and we have them do a sustained field exploration in geology or biology while operating under as many constraints as we can impose upon them. We try to find out what's going to work on Mars: what technology would work, what skill mixes would work, what character mixes, a lot of human-factor work, how you want to organize the crew. Do you have people on [military-style] watches, do you do it with everyone on the same schedule, and who leads it? Is it mission control, or the crew commander? What kind of field mobility systems are optimal, what kind of instruments are optimal—all kinds of stuff. So we now have had eleven crews at the Arctic station, and over one hundred crews [at] the desert station. At this point, over six hundred people have been part of one crew or another of our stations.

  “We've had all kinds of crews: mixed international, all-German crews, all-Australian crews, we've had all-male crews, all-female crews, everything you could think of. So now some six hundred people have had some experience of what the challenge is like, and they take that knowledge with them back into the workplace or wherever they are.”