The Quest for Mars: NASA scientists and Their Search for Life Beyond Earth

Meteorites have held a special fascination as relics from the heavens, mute messengers from parts unknown. In the Middle Ages, meteors falling to Earth generated superstition and concern. Where did they come from? What did they mean? The faithful brought them to the authorities, and in time, the Catholic Church acquired a large repository of these curiosities. In 1969, the study of meteorites underwent a quiet revolution when Japanese researchers found high concentrations of them preserved in arctic ice. Since 1977, NASA, a technological Vatican, has been collecting meteorites from Antarctica and housing them at the Johnson Space Center in Houston. Each year, there are hundreds of new arrivals, and when there’s a promising delivery, scientists clamor to get a piece to study. There are now nearly 10,000 rocks under lock and key in Building 31 at Johnson, many of them preserved in nitrogen. By measuring the radiation absorbed by the meteor during its space travels, scientists can determine approximately when the rock arrived on the Earth, and even how long it spent in space before it arrived on our planet.

In December 1984, Roberta Score was hunting for meteorites in Antarctica. At the time, she was employed by Lockheed Martin and working at the Johnson Space Center. Around Johnson, a meteorite collecting mission is not exactly choice duty; join one, and you were said to have become part of the “Houston weight loss program.” Walking across an apparently endless sheet of ice, Robbie Score came across a greenish stone about the size of a potato. Once she removed her sunglasses, she saw the meteorite was not greenish, after all; it was gray and brown, but she knew it looked different from the ordinary meteorites she found in the field. Along with other samples, it was kept in a freezer aboard the ship that brought it from Antarctica to Point Magu, California, where it was packed in dry ice and sent to Johnson, where it was stored in cabinets that once held moon rocks. The meteor curators, including Robbie Score, designated it ALH 84001 – their way of saying this was the most interesting meteorite collected in 1984 in the Allan Hills of Antarctica. But after being delivered to Johnson, ALH 84001 was misidentified as an asteroid fragment, a diogenite, rather than a piece of Mars, and stored in Building 31. It was not ignored, however; small sections were allocated to the scientific community for further study over the years; in all, almost a hundred “investigators” examined it, and everyone continued to misclassify it as a diogenite – with one exception.

In late 1993, David Mittlefehldt, a veteran Lockheed Martin scientist also working at Johnson, reexamined ALH 84001. Mittlefehldt was an expert on diogenites, and this particular rock didn’t look like one to him. It seemed to have more oxidized minerals in it than your normal diogenite, for one thing. Using new technology in the form of high-resolution laser spectrometry, two other scientists, Donald Bogard and Pratt Johnson, extracted gases trapped inside the strange meteorite and discovered that their very idiosyncratic characteristics exactly matched gases on Mars as measured by the Viking spacecraft in 1976. Mittlefehldt published his findings in 1994 in a scientific journal, and attracted the notice of the science community. Although this wasn’t the first meteorite from Mars to have been discovered, the reclassification created a stir. Of the thousands of meteorites that have been cataloged, only fourteen are believed to have come from Mars; the overwhelming majority come from asteroids, and a few from the moon. Meteorites are named for the places where they have fallen to Earth, so the Martian meteorites have some fairly exotic names – Shergotty (India), Nakhla (Egypt), and Chassigny (France), among them – and are known collectively as SNC or “snick” meteorites. “SNC meteorites” is an elaborate way of saying “meteorites from Mars.”

Carefully considering his find, Mittlefehldt noticed minuscule reddish-brownish areas deep within ALH 84001; they looked a lot like carbonates, and on Earth, carbonates such as limestone tend to form close to water. What made this all so curious was that no one had detected carbonates – and their suggestion of water – in the other Martian meteorites. They were billions of years newer; they probably came from a more recent era in the geologic history of Mars, after the water that once flowed freely across its surface had disappeared. This one, however, apparently harkened back to that warm and wet golden age on Mars. Dating confirmed that the meteorite was indeed very old: 4.5 billion years old, much older than other known Martian meteorites, and it contained carbonates that were 3.9 billion years old. Mittlefehldt wanted to get some idea of the temperature range in which the carbonates had formed billions of years ago, so he went to yet another NASA scientist, Everett Gibson, who examined the very curious meteorite with Chris Romanek; they published a paper in the December issue of Nature in which they said the carbonates had formed at temperatures below 100° C, in other words, at moderate, Earthlike temperatures – “well in the range for life processes to operate,” as Gibson puts it.

By now a line of reasoning was beginning to take shape. The team had their meteorite; it was from Mars. Almost no one disputed that singular fact. And it was very old, when water was thought to exist on the Red Planet. And it had carbonates, suggestive of water, formed at moderate, Earthlike temperatures. With each new discovery, the stakes became exponentially higher. ALH 84001 had gone from being a curiosity to an interesting and instructive case study to a potential harbinger of a scientific revolution. Each new link had been more difficult to fashion than those that had preceded it, and the final link – to life on Mars – would be the most difficult of all to fashion.

Other scientists soon began angling for a piece of the curious, potato-shaped Martian meteorite, among them David McKay. Over the years at Johnson, he’d become known as a solid and reliable scientist, not the type to go out on a limb. Carl Sagan he was not. If you asked around about McKay, you often heard words like “cautious” and “self-effacing,” yet he had a distinct air of authority; he’d published hundreds of scientific papers, and he knew his way around Johnson and around NASA. Over the decades, he’d learned about science and about maneuvering in the world of scientists. He knew about the pitfalls, how quick others were to leap on “discoveries” and tear them to bits. Yet with all his experience, he seemed destined to retire in honorable obscurity, until ALH 84001 came to his attention.

“I’m going to get a piece of that meteorite and look for signs of life in it,” he told his wife.

“Sure you are,” she said.

McKay had a vast storehouse of information and impressions about rocks on which to draw. In his long career, he had looked at perhaps 50,000 of them, and he spent many hours studying the most intriguing he’d ever seen, ALH 84001, with a scanning electron microscope capable of magnifying objects 30,000 times. With this instrument, McKay identified a bunch of – well, they looked a little like miniature subterranean carrots, or worms, or tubes. Whatever they were, they didn’t look like something you’d expect to find in a meteorite.

Again, he turned to another scientist for assistance. Kathie Thomas-Keprta was a biologist who had spent almost a decade studying extraterrestrial particles – space dust – before she focused her attention on the meteorite from Mars. She was accustomed to making do with very little. A specially modified B-57, flying at high altitude for an hour, might collect just one extraterrestrial particle from an asteroid, a particle too small to see but big enough for her to examine under a powerful microscope. When McKay invited her to study a Martian meteorite, she was delighted to have something as big as one millimeter by one millimeter to work on after all those years of studying specks. Even better, she was an expert with a new type of electron microscope that could reveal the mineral composition of the carbonates locked in the meteorite. McKay and Gibson showed her the photos taken by the scanning electron microscope, and they proposed that she examine those peculiar, worm-like structures to see if they were fossils. She listened respectfully to their proposal, and when she got home that night, Kathie told her husband, “These guys are nuts!”

A team of researchers based at Stanford subjected chips of the meteorite to further laser tests, which yielded polycylic aromatic hydrocarbons – PAHs, for short – which are often associated with life. That finding raised more questions than it answered, for PAHs are also associated with inorganic material such as pollution and exhaust. If that were the case, the carbon in the meteorite could be the result of very recent contamination on Earth, not evidence of ancient life on Mars. Additional tests showed that the PAHs were buried inside the meteorite and probably quite old, lessening the likelihood that they were the result of exhaust. It looked like the PAHs came from Mars, after all.

The team felt confident enough to announce some initial findings at the 1995 Lunar and Planetary Science Conference, held at the Johnson Space Center. In the planetary science community, the LPSC is a very big deal, a sort of scientific Super Bowl. If you don’t show up for this event, scientists say, everyone assumes you’ve died, and when you do show up, you come to make news, if you can. On behalf of the meteorite team, Kathie Thomas-Keprta presented a paper about the unusual and provocative features of ALH 84001 observed by the team. The paper stopped short of declaring they had found evidence of life on Mars, even very ancient, very tiny life. In fact, she adamantly denied it to a reporter from the Houston Chronicle who suspected she was hinting at it.

She knew other scientists would soon challenge her findings, no matter how cautiously expressed. Faulty science or clumsy handling of the situation could mar several carefully-tended careers. So McKay and his colleagues ran still more tests on the meteorite with an even more powerful scanning electron microscope designed to inspect rockets for minuscule fissures; this instrument was capable of magnifying objects up to 150,000 times. McKay put a four billion year-old piece of Mars under the microscope, and on his monitor there appeared a bunch of worm-like forms. He printed an image, and gave it to his teenage daughter.

“What does it look like to you?” she asked her father.

“Bacteria,” he answered.

Kathie Thomas-Keprta eventually decided the guys on her team weren’t nuts, after all. Her conversion occurred in Building 31 at the Johnson Space Center one night when she was working late. As she examined the shapes of the nano-fossils in the meteorite, she knew from experience they were of biological origin. “It was gregite, an iron sulfite present in the carbonate. It had a certain morphology known to be produced by bacteria. It was actually a biomarker, a thumbprint left by biological activity. I thought, ‘That’s it. There’s life on Mars.’

“I walked out the door to the parking lot, half-expecting to see flags waving and bands playing, but there was nothing at all out there, just a dark, empty parking lot at night.”

The chain of reasoning was more or less complete. The meteorite was old enough to contain of a record of Mars’ early days, when water was plentiful. It had carbonaceous material; it probably had Martian rather than terrestrial PAHs; and it had gregite, a universally accepted sign of biological activity. Although each distinct link could not be taken as proof, they all added up to a fairly strong argument for ancient life on Mars.

The team, now grown to nine, approached Science magazine. They realized that getting the prestigious journal to accept their paper would be difficult and delicate; they might have to withstand as many as four or five anonymous critiques of their work. Science was tempted by the paper but reluctant to support invalid conclusions, so the publication sent out the manuscript to nine readers. The resulting article relied solely on sober observations and rigorous science, and its title reeked of compromise: “Search for Past Life on Mars: Possible Relic of Biogenic Activity in Martian Meteorite ALH 84001.” The most important sentence was the summary: “Although there are alternative explanations for each of these phenomena when taken individually, when they are considered collectively … we conclude that they are evidence of primitive life on Mars.” In other words, the meteorite offered the first scientific evidence that ours is not the only planet in the Solar System where life emerged. Publication of the issue of Science containing the article was set for August 16, 1996.

When Jim Garvin heard about the impending Science paper, he felt the skin on the back of his neck prickle. “I was dumbstruck,” he said. In 1990, he had looked at another meteorite, Shergotty. At the time, no one realized that particular rock had come from Mars. He borrowed a piece of it from the Smithsonian, where it is stored. “I took it up to our lab and made the measurements I’d wanted to make for impact metamorphism” – looking for evidence of shock waves, that is. “This was a passive measurement, by the way, like bouncing a laser pointer off a rock; we weren’t destroying it.” There he was, examining a piece of Mars without realizing it.

The force of the new paradigm – that life on other planets was probably tiny – spun Jim’s thinking in a new direction. “We were still a few months before the launch of Pathfinder and Mars Global Surveyor, and the question was asked, ‘What could be done with these ready-to-go spacecraft to look for more signs of life?’ ” Suddenly, Jim’s Mars mission had a new reason for being. He had always believed it presumptuous to assume that life existed only on Earth, and he was sympathetic to the meteorite team’s conclusions about ALH 84001. Their research science was rigorous, it was cautious, and it was consistent with the latest findings concerning extremophile life. There was something in that meteorite that could not be explained away by conventional arguments. Jim agreed with the team that the burden of proof had now shifted to those who insisted there was no life on Mars. If that was the case, he said, “an interesting explanation as to why life failed to make at least a tenuous foothold would have to be crafted.”

The midsummer Martian madness started in earnest a couple of weeks before publication of the article, when Dan Goldin, the mercurial, publicity-loving head of NASA, heard that Science had accepted the article for publication. Next, the White House wanted to make a grand occasion out of the discovery of possible life on Mars. In preparation for the announcement, Goldin summoned David McKay and Everett Gibson to Washington. “We had thirty minutes scheduled with Dan to talk about the meteorite,” Everett told me. “After an hour and a half, Dan said, ‘You guys take a break, I’ve got some things to do, and then we’ll continue.’ During the break, he dictated a commencement address he was going to deliver at UCLA and handled a few other things, and then we continued for another hour and a half. I felt like I was giving an oral defense of a Ph.D. thesis. I mean, Dan went back to first principles, and he took twenty-eight pages of notes.” At the end of the ordeal, Dan Goldin had one last question for the two scientists: “Can I give you a hug?” The gesture was pure Goldin. In general, NASA is not a touchy-feely place – but Goldin is a man of enthusiasms.

After that, the story began to leak everywhere. Space News, a weekly trade journal, hinted at the forthcoming Science paper about ALH 84001, and the buzz preceding an important Washington story started; then things suddenly went awry. At the stylish Jefferson Hotel in Washington, Dick Morris, an advisor to President Clinton, told a prostitute named Sherry Rowlands about the discovery, in the vain hope of impressing her. “Is it a bean?” she asked. Well, no, not really, he replied. It was, uh, more like … a “vegetable in a rock.” When Rowlands got home and opened her diary to write about her day with Dick, she noted, “He said they found proof of life on Pluto.” Scientists dread being misunderstood by the public, but who could have imagined the magnitude of misunderstanding generated by this discovery? The situation deteriorated even further when the befuddled hooker tried to peddle the story to the tabloids, which turned out to be more interested in extraterrestrial life in the form of little green men than vegetables in rocks, thank you. And her inability to recall just what planet Dick said they’d found life on – Saturn, maybe? – didn’t help her credibility, either. There was no sale.

The life-on-Mars story quickly took on a life of its own. The CBS Evening News was making disturbing noises that it might break the news even before confirmation, according to an account that appeared in Texas Monthly. Other networks sensed news in the making and assigned reporters. Science tried to halt misunderstandings by posting the article on the Internet shortly before publication. On the first day alone, the website received over a million hits. Giving substance to an age-old dream, and terror, the article’s findings excited worldwide attention. The announcement gave new impetus to America’s expensive, beleaguered space program, especially its investigations of Mars. Goldin was delighted to confront a challenge of this magnitude, and the mood surrounding it recalled the great days of the space race, when Americans had an emotional investment in NASA and the nation’s fortunes seemed to rise and fall with the agency. But the issue of life on Mars was more complicated to explain to the public and sell to Congress than sending people to the moon had been. There was no life-on-Mars race for politicians to exploit. National security and national pride were not at stake. Only the science really mattered. The discovery involved concepts difficult for most people, even scientists, to understand, including a meteor of unimaginable age that had traveled to Earth from an unimaginable distance, containing evidence of life that was unimaginably tiny.

NASA finally made the announcement at a flashy press conference, at which an exuberant Dan Goldin proclaimed, “What a time to be alive!” (And the head of NASA, he might have added.) Bill Clinton, campaigning for reelection, appeared on the South Lawn of the White House to hail the discovery as if it were another triumph for his administration, but he actually sounded a note of caution that went largely ignored: “If this discovery is confirmed, it will surely be one of the most stunning insights into our universe that science has ever uncovered.” That was still a big if. And his declaration that the American space program would now “put its full intellectual power and technological prowess behind the search for further evidence of life on Mars” did not necessarily mean additional money for a beleaguered NASA. His words amounted to a mere presidential pat on the back.

The summer of Mars was underway. For a while, the names of the several NASA scientists on the meteorite team – McKay, in particular – were known to journalists and the general public. The sudden popularity threw the scientists for a loop. They naturally desired professional recognition, but not celebrity. In their line of work, being famous meant being considered suspect, a semi-charlatan, a talking head rather than a working research scientist. None of them aspired to become the next Carl Sagan, bridging the gaps among the media, the scientific community, and the public. Although their thinking was revolutionary, they weren’t visionaries; they just wanted their funding, and they wanted to pursue their scientific interests. The announcement concerning ALH 84001 made it harder for them do that, as publicity insinuated itself into the normally orderly process of disseminating scientific information. Instead of addressing specialists at conferences and publishing in specialized journals, science teams proclaimed their findings in press releases, in advance of publication. Freed of the constraints imposed in a refereed publication such as Science, the releases tended to make larger claims than the articles that inspired them. Conducting science by press release troubled many, including those engaged in the practice.

The announcement concerning ALH 84001 transformed NASA. For the first time, many people realized that NASA supports scientists, not just astronauts and engineers and the crews that send them into space. In its youth, NASA had accomplished one spectacular engineering feat after another: putting an astronaut in orbit, sending astronauts to the moon, keeping astronauts in orbit for months on end. These missions included science, but science was rarely the point. Flags and footprints on the moon were the point. Astronauts did collect a few hundred pounds of moon rocks for scientists to analyze, but the public had scant interest in lunar geology. Now, with the announcement of possible nanofossils in ALH 84001, NASA scientists were no longer overlooked. And with the end of the cold war, they could participate in missions that were primarily scientific rather than political, missions that might become more significant than sending people to the moon. They suddenly had an opportunity to devise experiments exploring fundamental questions about the nature of the universe and the origins of life. Their results of their search, a NASA report concluded, “may become a turning point in the history of civilization.”

The message in a bottle had arrived, but who would decipher it correctly?

Throughout the summer of 1996, David McKay expected a backlash concerning his discovery, but it was slow in coming. At first, members of the public, some of them deeply suspicious of all federal agencies, NASA included, sent him angry e-mails, most of which echoed the theme, “What kind of fools do you take us for?” One said, “Your life on Mars story is a good example of your mistaken belief that the general public is comprised of a bunch of total idiots.”

Eventually, scientists joined the clamor. Some insisted that ALH 84001 proved absolutely nothing. The wormlike structures, said critics, were far too small to be bacteria; in fact, they were many times smaller than the smallest bacteria ever seen on Earth. Others insisted that if the meteorite contained evidence of biological activity, it was the result of contamination. Still others challenged the team’s analysis of the PAHs. Some scientists stated flatly that McKay and his team had unfairly manipulated the evidence to support a flawed hypothesis. Everett Shock at Washington University invoked the Murchison meteorite, believed to have come from the asteroid belt, to invalidate the discovery. “It has carbonate minerals in it,” he said, “and real solid evidence of water – yet there isn’t anybody saying that there is life in the asteroid belt.” True, no one was saying it at the time, but that situation is beginning to change as scientists have come to think of life as widely distributed throughout the Solar System. Finally, the scientists attacked the reputations of McKay and his team, a tactic that took cooler heads by surprise. “It’s kind of strange when scientists, who are thought to be rational, become emotional,” said Marilyn Lindstrom, a curator of meteorites at the Johnson Space Center. “What bothers me most is that so many people have made up their minds before the data come in. I mean, sometimes I’m amazed by McKay and Gibson’s almost true-believer attitude.”

Carl Sagan was seriously ill at the time of the announcement, with only a few months to live. During his decades with NASA, he had become familiar with both the science and the passions involved in the search for life beyond Earth, and his pronouncement on the subject was enlightening yet equivocal. “For years I’ve been stressing with regard to UFOs that extraordinary claims require extraordinary evidence. The evidence for life on Mars is not yet extraordinary enough. But it’s a start.” Although he was deeply intrigued by the meteorite team’s findings, Sagan insisted that more study was required. Yet other scientists were convinced by McKay’s rigorous approach. “If this is not biology,” said Joseph Kirschvink of Caltech, “I am at a loss to explain what the hell is going on. I don’t know of anything else that can make crystals like that.”

Because McKay, Gibson, and company were cautious, even cunning, in the way they stated their findings, they made it difficult for their critics to disprove their argument. The meteorite team held that the fossils were merely possible evidence of relic life; they were not the only explanation for what they’d found, merely the best explanation. To disprove or dismiss these findings, their critics would have to understand ALH 84001 even better than the original investigators did. They would have to refute four separate, interrelated lines of argument. They would have to be familiar with geochemistry and physics and geology and of course biology. No one person knew enough about all these fields as they applied to the meteorite; it would take a team, a bigger and better team, to show McKay and his colleagues the error of their ways.

The significance of the debate transcended the meteorite itself. Even if it contained crystals that mimicked biological morphology, or contamination, the search for extraterrestrial life had undergone a sea change. Even scientists who thought ALH 84001 contained no life signs at all now found themselves thinking that if we were going to find evidence of extraterrestrial life, it would probably be tiny and ancient and carried throughout the Solar System in a meteorite. McKay, Gibson, and Thomas-Keprta’s real discovery was a new paradigm. Even if their conclusions turned out to be incorrect, their thinking was too sophisticated to dismiss. From now on, they would define the terms in the search for extraterrestrial life. Their credibility rested not so much on what they found as on how they found it: their precise, rigorous methodology.

Two years after the announcement, I found Kathie Thomas-Keprta in the featureless Building 31 at the Johnson Space Center, where many of the crucial discoveries concerning the meteorite had occurred. She is tall and slender, with long blond hair swept up in back. Despite the intense debate concerning her work, she didn’t look embattled; she was poised, with a certain swagger and the smooth delivery of a television talk show host, at least in one-on-one conversation. We were standing beside another Martian meteorite, EETA 79001, a cousin of the more famous ALH 84001. EETA 79001 resembles a black ice cube, about two inches by two inches. I peered carefully at this Martian specimen. There wasn’t much to see except for a little hole in one side drilled by a laser to extract gases trapped within.

Her team expected a lot of debate after their discovery, she told me, although the vehemence came as a surprise. “Still, all the criticism and attacks on our findings don’t bother me because I’m from Green Bay Wisconsin, and I’ve been a Packers fan for thirty years, and I know what it’s like to hang in there from one losing season to the next.” She thought it would take five to ten years for their findings to be fully vindicated, and she couldn’t wait for that day. Her case now was stronger than ever, she said. The recent discovery of microorganisms far below the Columbia River, in Washington State, gave her a lot of corroborating evidence for nano-life on Mars. No one expected to find nanobacteria a mile or more below the surface of the Earth, and no one knows how they started growing. Like their ancient Martian cousins, they live in basalt. More important, they are almost as small as the Martian nanofossils. Critics of the meteorite team insisted that the presumed nanofossils in ALH 84001 were much smaller than any organisms found on Earth – too small to be considered micro-organisms. Since the Columbia River discovery, that objection lost much of its force.

I wondered what kind of energy source for life could be found in rock a mile or two underground, where there is no sunlight, no lightning, no real heat from the Earth’s core. Some scientists think the source could be as simple as water passing over the basalt, which might cause a chemical reaction. If this is the case, the answer to the Genesis Question becomes simpler all the time; it appears that the rock bottom (so it might be said) requirements for life are even more minimal than scientists believed only a few years earlier. All you need is water and an energy source for life to emerge. Water might be running through subsurface basalt everywhere; the same thing might have happened on other planets, or even on asteroids; it might be happening now. There might be more ways for life to emerge than we now imagine – enough to suggest that life really is an inevitable outcome of chemistry and an inevitable part of the universe, predestined, as it were, but so simple that we hardly acknowledge the phenomenon for what it is.

David McKay is tall, slender, silver-haired, professorial, imposing. As the leader of the meteorite team, he is suspicious of outsiders and chooses his words with care. His office, where we met, is capacious, even by the standards of the sprawling Johnson Space Center, and the walls are lined to the ceiling with plaques, awards, degrees, citations, and a child’s squiggly drawing of a small Martian meteorite beside a large man labeled, “Dad.”

“We are still getting new data,” he said, as he snacked on a small bag of pretzels, eying me warily. He wasn’t exactly thrilled that I’d appeared in his lair; he was sensitive to criticism and assumed I was about to add my voice to the chorus of those who angrily criticized his findings. He was about to dismiss me – or so it seemed – but he thought again, and decided to test his case with me. “We are very excited about the data from the meteorite called Nakhla that fell in Egypt in 1971,” he said. “The British Museum had a piece the size of a potato, covered with fusion crust, which protects it from contamination. The problem with the Allan Hills meteorite, ALH 84001, is that it may have been contaminated with carbon or terrestrial bacteria. A chunk of the Nakhla meteorite came in here, to our lab, and we had permission to break it up and pass it out to various investigators. We requested six grams. We think it’s likely to have the least contamination of any Martian meteorite.” I sensed he knew more, but this partial revelation was all he would risk revealing at the time.

He also wanted me to know he hadn’t given up on ALH 84001 as the prime suspect in the search for life on Mars. He didn’t want me to think for one second that Nakhla was a substitute for ALH 84001; rather, it offered supporting evidence. As he talked, it became apparent that he felt that all the criticisms leveled at his findings, and there had been a lot of them, more than most scientists encounter in a lifetime, had only strengthened the arguments he originally advanced. To illustrate what he meant, he invited me to sit with him before a large monitor. “Here’s a new picture from the Allan Hills meteorite. We really suspect these are fossilized bacteria. They have better characteristics than what we have already seen; they are curved, segmented. If you gave this to a biologist, he’d say, ‘Of course it’s bacteria,’ but we have to prove beyond a shadow of a doubt it’s of Martian origin and fossilized. Fossilization is very common with bacteria; the organic components are replaced by mineral components such as iron oxide or silica. This can happen quickly, in a couple of weeks, and it happens when you bury the material in water. They are one hundred to two hundred nanometers long and forty to fifty nanometers wide, smaller than the big worms in the published pictures, which were five hundred nanometers long. My guess is that life is still on Mars, but it’s underground, in the water system. That’s where the underground organisms are living, a couple of kilometers underground. On Earth,” he reminded me, “there are microbes growing four kilometers underground.”

As we parted, David McKay insisted, “Our critics have proved nothing. Our research has defeated each and every one of their arguments, and the case for ancient life on Mars is now stronger than ever.”

Nine months after our meeting, McKay made his latest findings public at the 1999 Lunar and Planetary Science Conference in Houston; his announcement added to the controversy and ensured that the debate surrounding fossilized Martian bacteria would continue for years. To his way of thinking, there were now two meteorites from Mars bearing evidence of fossilized bacteria, ALH 84001 and the newcomer, from Nakhla, Egypt. His detractors claimed his analysis of the newer meteorite, Nakhla, compounded the errors he had made in his analysis of the first, but his supporters insisted it offered compelling confirmation of extraterrestrial life.

3 GROUND TRUTH (#ulink_9dd2d5f6-be70-531c-a359-c187ff70c38d)

To reach the Jet Propulsion Laboratory, you take the freeway to Pasadena and get off at the Oak Grove Exit, then follow Oak Grove as it winds gently toward the mountains through the luxuriant landscape. You feel the smog settle on your chest as you go. There’s no suggestion of high technology in the area, just a somnolent Southern California suburb, lush, green, and slightly sullen. As you sense the end of the road approaching, you assess the looming mountains, but there’s still no sign of JPL, and you begin to wonder what gives. JPL isn’t exactly off-limits, but it’s not easily accessible, either. It will be found only by those who put some thought into looking for it. You think you’re finally there when several large white modern structures appear on the left, but as you drive up to them, you realize it’s a local high school, and then, just ahead, there’s a gate and a guardhouse, and that, at last, is JPL.

People arrive for work early. By 7:30 AM, the parking lot is filled with Hondas and Fords and Nissans and Tauruses – nothing fancy, except the odd Corvette. Employees quietly fan out across the campus and go to work. The buildings at JPL are boxy, functional, crisp. Within its offices, there are the same horrible green plants you see everywhere at NASA, at headquarters or the Johnson Space Center in Houston. Once you’re indoors, you can forget all about Southern California; you might as well be in Washington or Florida; it’s NASA-land.

Despite its innocuous location, JPL is among the world’s leading centers for spacecraft engineering and development. Started in 1936 as the Guggenheim Aeronautical Laboratory at the California Institute of Technology, JPL is now run jointly by NASA and Caltech. In the early days, there were just a few people on hand, including Frank Malina, a rocket enthusiast, and Theodore von Kármán, an influential Caltech professor. The lab barely survived the Depression, but it got a boost during World War II for experiments in rocketry. During the fifties, JPL developed a satellite that, according to legend, could have beaten Sputnik into orbit by a few months and irrevocably changed the space race – if it had been launched. Throughout the sixties, JPL solidified its reputation as the place for robotics – unmanned spacecraft destined for the moon and the planets – but it lacked the high profile of the Johnson Space Center in Houston or the Kennedy Space Center in Florida.

All that changed with the advent of the new Mars program in 1992, when a new generation of employees began streaming into JPL, reinvigorating the place. Unlike many of the old timers, they hadn’t come out of the military or the aerospace industry, they were just out of grad school, and had grown up watching the space program on television. They were young, and they weren’t burdened by the past. The men wore earrings and pony tails instead of military buzz cuts, and tie-dyed t-shirts replaced white polyester short-sleeve button-down shirts and narrow black ties. But that was just the men. Many of the new recruits were women, and among them was Jennifer Harris.

Growing up on her family’s farm in Fostoria, Ohio, Jennifer never expected to explore Mars or to become a flight manager for a Mars mission. She wanted to be a concert pianist. She played the piano, the saxophone, marimbas, bassoon, trumpet, tuba; she was a one-woman band. On the other hand, she loved math and competed successfully in county-wide math competitions. Astrophysics excited her imagination, especially black holes; she loved just thinking about them. In the summer before her senior year in high school, she went to music camp, where she realized that her survival as a concert pianist would depend on her ability to practice every waking moment, and she wasn’t sure that was what she wanted to do with her life. She also wanted to travel, to meet people; she was even thinking of becoming a missionary. When MIT accepted her, she went into a mild state of shock. Eventually, she chose to major in Aerospace Engineering – partly because it sounded like the coolest thing she could do and partly because her father had tested missiles for NASA when he was younger, and she had come of age hearing his tales of countdowns, halts, and explosions. Or maybe the picture of a rocket on a wall in the den of her home influenced her decision. After graduation, she went to work for the Jet Propulsion Laboratory.

Even after she arrived at JPL, Jennifer was restless. They were designing spacecraft on spec, hoping to get funding from Congress, and most projects never did. If a project actually received a green light, the lead time was awfully long. As she toiled away at her subsystems, she couldn’t see where her little cog fit into the machine, or if there even was a machine. She began to ask herself, “Is this all there is?”

She was single and didn’t have any serious ties to Pasadena or JPL. She chose to take a leave of absence, without assurance that a job would be waiting for her when she returned, if she returned. She still wanted to see the world and meet people, so she decided to do missionary work in Russia. She was assigned to Sevastapol, in the Crimea, near the Black Sea, where the conditions were unbelievably grim. There was no hot water, and they lived in cement buildings that were always cold and damp. A lot of the population were flat-out atheists. The economic situation was horrendous. She was paid about $30 a week, which made her among the wealthiest citizens of the town. Everyone around her was subsisting in a barter economy, using coupons instead of cash; one Snickers bar, for instance, cost 2,000 coupons. She and her friends based everything on the cost of a Snickers bar, but that didn’t help keep track of finances, because the inflation was incredible. Pretty soon that Snickers bar cost 8,000 coupons, then 16,000. People who had saved throughout their entire lives lost their fortunes overnight when the ruble crashed.

At times she wondered what kind of space program the Russians could possibly mount under these conditions. She had to wonder how they got anything done. As if the Russians’ pervasive fatalism wasn’t enough, there was the corruption, another thing she hadn’t been exposed to back at MIT and JPL and the family farm. She knew evil when she saw it, though, and it seemed to her that Russia, or at least her speck of it, was basically run by the Mafia, the politicians, and the church, all in bed together. After a while, she wondered if she was meant to be doing missionary work, if it was really the best use of her abilities. Was this what God wanted her to do? Was this what she wanted to do? She had to say honestly that the answer was no, her education was going to waste here. When her tour of duty was over, she left Russia to wander around Europe.