by Marc Kaufman
Conrad wanted to come back at night because the Raman spectrometer works much better without light interference, and during the day Badwater was nothing but that. The moon was rising over the Amargosa Range on the eastern side of the valley just as the sun had begun to light the sky when we first arrived at the site sixteen hours before. We walked a ways on the salt pathway and, using her miner’s light to scan the landscape, Conrad found another spot to analyze, this time pursuing “extreme science.”
To help explain the differences in electrical charge, Conrad needed to know exactly what minerals and elements made up the white and brown deposits. She had already taken samples to analyze in her lab—which for twelve years was at NASA’s Jet Propulsion Laboratory, but would soon be at the agency’s Goddard Space Flight Center—but doing work in the field is part of her self-imposed training for the Mars mission. So she proceeded as if Death Valley were Mars, and set out to learn then and there what was putting out those very different electric charges and why.
Space missions are famous for their glitches, and we had one with the Toughbook and spectrometer. For more than an hour the computer refused to read what the Raman was picking up, and there were any number of reasons why. The instruments had been exposed to great heat in the car trunk, they were now being buffeted by wind in what amounted to an enormous salt bowl, and the temperatures were substantially below what they had been several hours before. Nothing so dramatic as conditions on Mars, but an extreme changeability nonetheless. The moon was fully overhead when finally the first squiggly lines of a spectral pattern showed up. Each peak on the graph is the signature spectral pattern of a vibrating bond between atoms in a mineral or compound; collected, the peaks reveal the identity of the ray-gunned materials. The graphs for the white valleys were, not surprisingly, very different from the brownish peaks. It was quite a sight. Conrad, seated on a tarp in a failed effort to get comfortable on the hard jumble below, the glow of the Toughbook, and another member of the team carefully moving the spectrometer ray gun from white to brown and back to white again. The moonglow kept away complete darkness, but it was well into the night and we were out on the Badwater salt with no other humans for miles around. It was noiseless, except for the wind. Mars in the day; Mars at night.
Death Valley is a popular site for Mars analogue research, but it’s nothing compared to Svalbard, a region on the northern tip of Norway, well into the Arctic Circle. When the men and women who run Martian or lunar or other planetary experiments want to try out their equipment and learn the challenges, they now regularly go to Svalbard, an archipelago of islands best known for the town of Spitsbergen, their harsh beauty, and their three-thousand-plus polar bears. These animals are sufficiently fierce that when researchers (or any locals) go out of the towns, they are required to take a shotgun. It’s a place that’s often fogged in, where instruments can quickly die outside if not kept properly warm, where romances tend to flourish and breakdowns are not unheard-of, and where astrobiologists can do great research and can test their Mars or lunar rovers and other experimental equipment. And in the arctic summer, when the expeditions occur, it’s light twenty-four hours a day.
The expeditions remain under the leadership of a Norwegian geologist named Hans Erik Amundsen, who did his doctoral research in Svalbard starting in 1997 and organized the first, almost impromptu international mission in 2003. The site has become valuable not only for testing instruments and training people on how to use them in Mars-like conditions, but also as a kind of scientific Outward Bound. “Nobody’s allowed to work alone, and nobody goes ashore unless they’ve been trained on what to do if you encounter a polar bear. Everyone is in a group of maybe four to seven people with radio communication to the boat. Everyone has to be accounted for all the time, and at least one team member has a rifle and flare guns in case they come across a bear,” says Amundsen. Many on the expeditions are high-powered scientists and engineers, and they often work by themselves and control their days. “They’re alpha personalities, but all that has to be put aside and they have to meld into a team,” is how Amundsen puts it.
The 2008 and 2009 expeditions focused on testing instruments for the Mars Science Laboratory scheduled to launch in 2011 and land on Mars in 2012. Although its mission is to determine “habitability” on Mars, scientists on the MSL team are convinced that the rover, the size of a Mini Cooper and weighing in at almost one ton, actually could detect life under certain circumstances. They say it, however, in something of a whisper. That’s because the rover and all its instruments would have to be sterilized to a higher and far more expensive level if MSL were officially deemed a “life detection” mission. So being slightly less than that has its advantages.
Svalbard is a great test range for cutting-edge ideas, as well as new equipment. Mars scientists disagree about many things, but one that unifies most of them is the long-term goal of a “sample return” mission: sending a spaceship to Mars, collecting some especially promising rocks and minerals, and bringing them uncontaminated back to Earth via another spaceship. The challenges are enormous, but the United States does have an impressive track record on Mars—it’s the only nation to ever land a spacecraft safely on the planet; the Russians tried many times unsuccessfully, as did the British with their Beagle spacecraft. But now, NASA and ESA have not only joined up for the ExoMars missions to measure trace gases like methane and then to land rovers on the planet in 2016 and 2018; they’ve also begun brainstorming and testing out ways to collect rock samples on Mars and bring them back to Earth. Svalbard has become a test site again for prototypes of the rover that will collect and then safely store the samples, called the Mars Astrobiology Explorer-Cacher, or MAX-C.
But the immediate project on everyone’s mind is MSL, and the man in the spotlight for that is Paul Mahaffy, a two-time Svalbard expedition member and the principal investigator for the Sample Analysis at Mars, the many-faceted instrument on MSL designed to detect organic material and possibly life. A somewhat rumpled, low-key physical chemist, he will oversee a team of several dozen people who will conduct the most extensive and most significant investigation ever on the Martian surface for the kinds of organic, carbon-based materials that could lead to or be associated with life. Other instruments on MSL will definitively determine if minerals present were formed, as expected, in the presence of water, while another will shoot out an intense laser beam that will vaporize a small amount of nearby rock, allowing a spectrometer to then read much better what the rock is made of. Another instrument will be able to sniff for methane, which after Mumma’s discovery has become a high priority. The reach of all these instruments will be greatly expanded by the ability of MSL to travel at least twelve miles during its two-year tour of Martian duty.
Mahaffy brought several off-the-shelf versions of SAM instruments with him to Svalbard, but the real SAM remained in a locked clean room at Goddard Space Flight Center. That’s where I had seen it earlier, and it was quite a technological and aesthetic marvel.
In my short time with SAM, I was startled time and again by what it can do. It has, for instance, little heat chambers where rocks and sediments are baked into gases, and these can reach 1,000 degrees Celsius using but forty watts of electricity. Although it’s tucked into the larger rover, SAM will be exposed to temperatures ranging from –40 to +40 degrees Celsius, sometimes in a matter of hours. It carries a “tunable laser spectrometer” that bounces received laser light some fifty times between two mirrors before it measures how the light is absorbed for gases like methane. The instrument can detect methane to a level of parts per billion. The maze of pipes and circuits and wires needed to run SAM so it can learn whether a particular piece of Martian rock has biologically produced molecules, or precursor molecules, or the extreme long shot of living molecules, is almost laughably complex. But the overall effect is of elegance, in part because the SAM containment box is plated in gold. Mahaffy said it’s essential for controlling “thermal response.”
Do scientists
really think they’ll find something—some sign of past or present Martian life? Probably nobody knows more about that question now than Steve Squyres, the Cornell University astronomer and planetary scientist who has led NASA’s rover missions Spirit and Opportunity since they landed, packed into two large bouncing balls, on Mars in early 2004. These are the little rovers that could, the ones that were expected to pass out some ninety days into their mission, but instead were still going more than six years later. As they’ve wandered their little patches of Mars, they’ve collected more data about the planet than any other mission, and Squyres has been in the driver’s seat the whole time. He’s also now a Svalbard regular.
Results from the rovers, he said, “show more convincingly that Mars at some point in its past was a habitable world. You have to be careful, and I’m always reminded of the parable of the blind man and the elephant: We have two little, tiny spots on Mars we’re looking at and we have to be careful about what we conclude. But the rovers are in very different places, and both show compelling evidence of near surface water, of interaction of that water with rocks and minerals, and in the case of Spirit site, you have hydrothermal activity—hot water and steam. These are the features that on Earth lead to local habitable niches.”
It was quite definitive, and Squyres is hardly a starry-eyed newcomer. I met him at an astrobiology conference where he discussed and sought feedback about NASA’s planetary sciences road map for the next ten years, an effort that he leads. I wanted to make sure I understood what he was saying, so I asked if the rovers have nailed that habitability question.
“I feel that they have,” he replied, with a glint in his eye. “Yes.”
6 THREE EUREKAS ON HOLD
You would think that a science that has fought so hard to be taken seriously would nourish a culture of dissent. But perhaps because of its urge for legitimacy, or because the discipline itself so often enters terra incognita, astrobiology has shown a consistent need to enforce a consensus. That is evident in the way it can treat those who diverge from the general view of what constitutes life on Mars and other celestial bodies.
Three reputable, diligent, and veteran researchers, for instance, are convinced that they have detected or even seen remains of life from Mars and from other celestial bodies. But not a single one can fill a hotel meeting room with their argument. Two are career NASA scientists who now carry the title of astrobiologist, and one was the creator and principal investigator for the main life-detection experiment sent to the surface of Mars for the two 1976 Viking missions. Together they have some seven decades of experience researching and analyzing experiments about extreme and extraterrestrial life, and two have been at center stage for some of the most important moments in NASA history.
Yet when the three took their places with others on a small side room dais at the Marriott Hotel in San Diego to address the topic of “Life in the Cosmos,” few of the five thousand scientists attending the conference they were part of—hosted by the optics and imaging organization SPIE—were anywhere to be found. The Marriott’s Marina Ballroom, Salon F, has seats for about 130 people, but on that summer night in 2009 only a quarter were filled. So it goes when the scientific community has concluded you’re off base on a subject as charged as extraterrestrial life.
The first to unspool his findings was David McKay, the NASA researcher who introduced the world to the softball-sized meteorite from Mars that, for a short time in the mid-1990s, was hailed as containing strong evidence that life once existed on that planet. He and his team at the Johnson Space Center never claimed they had proven the rock, found in 1984 in the remote and meteorite-rich section of Antarctica called Allan Hills (and named ALH 84001), had been home to living microbes. Rather, they reported finding five distinctive characteristics of the rock, determined through various chemical analyses to be Martian and about 4.2 billion years old. Those characteristics are generally associated on Earth with microbial activity. McKay did report the possibility that the meteorite contained a Martian “microfossil”—the minute remains of the outer sheath of a bacterium—but his strongest results involved the presence of minerals and rock alternations that are considered signs that bacteria and other microbes were once at work eating the rock, transforming the rock, and depositing waste in the rock.
Not surprisingly, “proof of life on Mars” is the way the story played when it came out with a bang in 1996, and the “microfossil” was the star of the show. The discovery was featured in a major article in the journal Science, a full NASA press conference with two hundred reporters and cameramen present, and these words from President Bill Clinton: “Today Rock 84001 speaks to us across all those billions of years and millions of miles. It speaks of the possibility of life. If this discovery is confirmed, it will surely be one of the most stunning insights into our universe that science has ever uncovered.” But in a foreshadowing of the bizarreness to come, the article was rushed into print because news about “life on Mars” was beginning to leak out. The source: a prostitute who was in the hire of Clinton political consultant Dick Morris. The president had apparently told Morris about the breakthrough, and Morris had told his companion, who then took the news to the tabloids.
Still, for a while McKay and his colleagues were on top of the scientific world, invited and feted everywhere. But like a pitcher whose nohitter is spoiled in the ninth inning and who then loses the game, McKay quickly went from hero to goat. His team and their findings were subject to a fierce and wounding attack by other specialists in meteorites, geology, microbiology, and the study of ancient life-forms in rocks. That the Martian meteorite paper would inspire other scientists to study and criticize its methodologies and findings is hardly surprising—that’s how science works. But that doesn’t mean emotions and human defensiveness, offensiveness, and grandstanding weren’t also at play. Attacking and defending the paper soon became a blood sport, an often brass-knuckled and highly personal struggle over the true contents and meaning of the meteorite. Suffice it to say that fourteen years after the paper was published, much of the scientific community has dismissed it, or at least concluded that it didn’t offer the “proof” that it actually never purported to offer. McKay, who needed quadruple heart bypass surgery a year after the controversy exploded, has spent much of the intervening time responding to his critics, doing the experiments and reexamining the data in the hope that he can convince the world that the Allan Hills meteorite really did once house living Martian organisms.
Given this history, it was no surprise that McKay took shots that day at the Marriott at both his scientific critics and at a press corps that he said jumped on all the doubts raised about his work but seldom was interested when those critiques were found to be wanting. “What I would like to do today, if I can, is convince you that the Martian meteorite studies are very much alive, and furthermore that the evidence is becoming stronger all the time that Mars meteorites contain evidence for life on Mars,” he began. “Now that sounds like an opinion, but I hope to reinforce that with some facts.” What followed was a detailed and emphatic recounting of where things stood regarding both the original Mars meteorite and several others that McKay and his team have examined.
McKay’s story goes like this, and is quite persuasive: His initial research led him to conclude that rock from Mars contained slightly magnetic grains or crystals that, on Earth, are often produced by bacteria that use and leave behind when they die signatures of the planet’s magnetic field. The McKay team’s original assertion that the meteorite held these magnetites was attacked as near ridiculous, since nobody had ever detected the presence or remnants of a magnetic field on or around Mars, either now or in the past. In addition, magnetites, like so many possible microscopic signs that living organisms once were present, can also be formed through nonbiological processes, and at least eight substantial papers have been written arguing for a range of origins that had nothing to do with life. The most common counterargument has been that the magnetites were formed when as
teroids, perhaps the one that ejected the meteorite, hit Mars about fifteen million years ago and formed magnetites in the resulting shock and enormous heat.
But the McKay case was substantially strengthened in the late 1990s when the Mars Surveyor orbiter did detect remnant signs of an ancient magnetic field on the planet. It was a huge coup: McKay’s prediction based on his early research—in this case, that Mars once had a magnetic field—was actually confirmed with observed data and measurements. Making predictions which are ultimately proved correct greatly strengthens any hypothesis. McKay then followed up with another rebuttal to his critics: His team published years of lab work that found the ALH 84001 magnetites were too pure and their concentration was too great to be explained by the contending “thermal shock” hypothesis—that they were formed in the scalding heat of a meteorite impact. In addition, a mineral needed to form magnetites nonbiologically was not present in the meteorite. Their conclusion: The magnetites were the mineral remains left by bacteria on Mars that, like some bacteria on Earth, contain magnetic crystals.
But McKay and colleagues Kathie Thomas-Keprta and Everett Gibson didn’t get the rehabilitation they craved. Their foes kept insisting the original research was botched. For instance, Allan Treiman, a senior scientist at the Lunar and Planetary Institute, located in Houston, wrote in a 2009 paper that it was hard to disentangle the origins of ALH 84001 in part because the clues present have been “muddied by now-discredited claims for biological activity.” Treiman later told me: “Would any reasonable person conclude that there was life on Mars based on the proportion of magnesium in submicron grains of magnetite?”
