The Rock From Mars (28 page)

The people who studied Mars most intently, whose work it was to plan these interplanetary excursions, had adopted a single organizing principle: follow the water. The edict became the overarching theme of the struggle to understand the evolution, geology, atmosphere, potential for biology—every aspect of the planetary personality of the red planet. Data flowing from the arriving robot explorers would soon churn up baffling evidence concerning the riddle of the Martian waters, shaking up many of the old assumptions.

Even as they fought about the meaning of one tiny chunk of the other world, some of the combatants were finding a kind of cease-fire zone in this work directed toward the world itself—the pipeline of missions to Mars. No matter how violent their differences over the rock ALH84001, the warring factions agreed that many of their most vexing questions could be resolved only on Mars itself.

The ancient rock that divided them was pressing all of them back toward its cradle, toward Mars.

In 1997, in the aftermath of the rock fight, John Rummel held the title of “planetary protection officer.” In casual moments, he would confide that, based on the reactions he got from kids and even some grown-ups, it seemed the next best thing to wearing Superman’s
S
on his chest.

But he was no comic-book action hero. He was an agent of the U.S. government working in the real world, a former naval officer who had flown anti-submarine warfare missions and then become an ecologist and sometime microbiologist. On occasion, he would recall that he’d begun his scientific career sailing the Caribbean studying lizard population densities; then he would laugh to himself and wonder, “How did I end up here?”

One big reason was the shift toward biology within NASA. After the McKay team’s 1996 announcement, administrator Goldin had expressed dismay at the dearth of biological expertise in the space agency culture (except for studies geared to astronaut health). He directed NASA to start hiring biologists, all kinds of biologists. Goldin would also soon set up the NASA Astrobiology Institute in California and hire a Nobel prizewinner to run it.

Rummel was NASA’s man in charge of ensuring that we humans prevent contamination of our own planet by alien microbes, and also avoid the spread of our own ecological undesirables to Mars or other sites in our little corner of space. He was supposed to oversee the writing of the rules.

The main focus of the planetary protector’s concerns was summed up in the term “sample return.” This referred to scientists’ cherished goal of dispatching a team of robots to gather and bring back rocks and soil from Mars. Simple as it might sound, it would be enormously tricky and expensive to design a robotic package that was (a) lightweight enough to be practical, (b) smart enough to do the job (make a sophisticated selection of desirable rocks and soils, for example), (c) able to land safely on the rugged Martian landscapes designated as most promising for biological clues, (d) able to take off again, and (e) able to deposit the treasure safely and cleanly back on Earth. And, again, there were related, and increasingly convoluted, issues of contamination.

In early 1997, a blue-ribbon science panel warned that the possibility of bringing back dangerous Martian life-forms, while small, was not zero. At a time when Ebola outbreaks, genetically altered agricultural produce, and bioterrorism had revved up global anxieties, Rummel and others felt unprecedented pressure to make sure the public was comfortable with the protective measures taken by their government.

The National Academy of Sciences mobilized some of the brightest minds in microbiology to figure out methods for complying with the Rummel Rules. They hammered out standards for biological signatures and ruminated on the challenges of differentiating dormant life-forms from active or dead ones, as well as distinguishing between life and nonlife—distinctions that remained frustratingly elusive. The very ambiguity of the evidence in the Mars rock became a catalyst for change in NASA’s approach to this issue and the design of the sample-return mission.

The Mars rock dispute helped planners realize how far short they fell in terms of the level of understanding and technology required to justify the stunning costs ($2 billion or more) and the years of effort involved in landing equipment to pick up maybe two pounds of carefully targeted Martian soil and rock, then launching the cargo back to Earth.

The anti-contamination people decided they would have to assemble not only a much better knowledge base but an arsenal of new technologies and techniques, containment facilities, and tools that would constitute an effective twenty-first-century Maginot Line against interplanetary contamination in all its modes.

Engineers pondered such arcane questions as how to detect possible pathogen leaks on an Earthward-bound sample freighter in time to redirect it past the home planet. Higher-level officials debated whether, if the samples were allowed to parachute to Earth, the retrieval teams should be from NASA, the military, the Centers for Disease Control and Prevention, or some other group.

Rummel somehow had to make the imperatives of planetary protection mesh with the primary purpose of the mission: the widespread distribution of the Mars samples among expert Earthlings. The goal was to ensure sophisticated analysis of the samples by the best instruments and minds available on Earth. But those two designs were sometimes in direct conflict.

A central question for those working on the quarantine issue was: What criteria must be satisfied before the samples could be released to waiting scientists around the world for study? The answer involved such trivial issues as how to determine whether the samples had life in them and, if so, whether this life was a danger to Earth—the very questions that the Mars rock controversy had demonstrated would be infernally difficult to answer.

And beyond the sample-collection project, the notion of sending humans to Mars seemed to recede even further into the future. Even if such a mission were technically and financially feasible, there was the freshly exposed worry that “sending humans may alter the biological history of Mars,” as astrobiologist Michael Meyer told a colleague. “You have a couple of problems. One is you’re likely not to recognize something [alive] on Mars because you’ve overwhelmed it with your own biology, and the other is you might end up contaminating the planet.”

In late 1999, with breathtaking suddenness, NASA’s bold blueprint for the Mars investigations fell into ruins. Mission teams based in Pasadena, at Caltech and the Jet Propulsion Laboratory, as well as in a control room in Denver, watched in disbelief as first one and then another catastrophic failure wiped out an entire generation of U.S. missions as they arrived at the planet. An orbiter and, three months later, a lander carrying two small surface probes crashed before they could begin work. White-haired planetary geologists saw a significant chunk of their life’s work, and their hopes, vanish in a digital blink.

The losses, eventually traced to avoidable errors, staggered NASA’s planetary program and demonstrated that there was a practical limit to Goldin’s “faster, better, cheaper” strategy. Overburdened managers in this case had failed to follow the rules designed to prevent such errors, and had stretched their teams too far.

Huntress, for one, was appalled as he watched Goldin shrink back from his bold push to encourage prudent risk taking throughout the space agency. Instead, in the wake of the Mars disasters, Huntress saw the policy transformed to “thou shalt not fail,” and the culture tilted toward one of “inquisition” and fearfulness.

The failures of 1999, combined with the controversy over the rock and puzzlements cropping up in the scientific data from the orbiting Mars Global Surveyor already at the red planet, forced mission planners to rethink virtually their entire repertoire of techniques and strategies for exploring Mars.

NASA officials pushed the vaunted capture of Martian samples more than a decade further into the future, until at least 2014, mainly because of the lack of money in the wake of the failures. But among those privy to all the scientific uncertainties, there was also the sense that they had dodged a bullet—and a suspicion that even an extra decade might not be enough to lay all the necessary groundwork. They had realized they were simply not prepared.

The scientists’ heady days of White House summitry and their dreams of ambitious exploration suddenly seemed at least as far away as the florid and treacherous sister planet. To many, the turn of events was like a warning echoing across interplanetary space: “You are not ready.”

CHAPTER TWELVE

AT DAGGERS DRAWN

O
N
A
UGUST
7, 1996, Andrew Steele—“Steelie” to his friends—was lying in bed at home in Portsmouth, on the southern coast of England, when he heard the headline on the BBC: “Life on Mars?!” He had dislocated his knee playing football (soccer, in American parlance), and his leg was in a plaster cast. But his imagination was leaping.

With his chiseled features, aquiline nose, and flowing mane of light-brown hair, he could have been a rock star or an
Esquire
model, but he was, instead, a cheeky microbiologist with a droll sense of humor and a shiny new Ph.D. from the University of Portsmouth. He had focused his attentions so far on the interactions between bacterial biofilms and metal surfaces in marine and freshwater settings. His goal was to learn more about the corrosion caused by microbes, and especially the role of bacterial slimes in the corrosion process. His project was sponsored by the U.K. nuclear industry.

But Steele was something of a romantic, quietly idealistic and already a bit restive at the prospect of a career in what he and his friends sometimes referred to—with great affection, of course—as “stools and fuels.” He had been an avid reader of science fiction all his life, and he knew something about the recent discoveries of organisms thriving in extreme environments. He found himself yearning to be part of that excitement. Now, as he nursed his knee, he heard the siren song of the red planet. He felt the surge of public fervor at the news. It got his heart to thumping, and agitated his mind.

Steele didn’t have a phone at home, so he hobbled into the lab where he was continuing work as a postdoc. He dialed the international information service and asked for the number of Johnson Space Center. He called David McKay’s office, spoke with an assistant, and explained that he was a specialist on a high-powered instrument called the atomic force microscope. He said, “I think I could probably get you a three-D image of the ‘worm.’ ”

Following the assistant’s instructions, Steele sent McKay a written “mini-proposal.” For weeks, he heard nothing. His friends in the lab teased him:

“You’re going to get a piece of Mars? Oh, yeah. Right.”

His supervisor told him, “You’re mad, mate. You’re mental!”

Surely, they said, the McKay group had already subjected their rock to the atomic force microscope.

The McKay group had not.

In mid-September 1996, McKay was called to testify before a congressional committee, where he mentioned that he was sending a piece of the meteorite to the University of Portsmouth, in England, for expert microscopy. The young Brit, who had never seen a meteorite before in his life, couldn’t believe his eyes when he read McKay’s comments in
Science.

After several more attempts, Steele finally got through on the phone to McKay himself, who told him that, indeed, the package would be arriving by FedEx. McKay explained that, as a result of Steele’s first phone call, he had queried other experts about the feasibility of the atomic force microscope technique. He had sent a piece of the rock off to the maker of the microscope. The feedback was encouraging.

Steele told his friends this thing was really happening. But his sense of humor was familiar to them, and they figured he was just winding them up.

One chilly day in November, the package arrived. Steele and his chastened friends took pictures to record the event. They were half afraid to open the thing. When Steele finally did unwrap the contents—a plastic vial—he thought there had been some mistake, or possibly a prank. The vial was empty, wasn’t it? They saw nothing at all in there.

Distressed, he called McKay. “Uhhhh, you can’t see it in there. Are you sure you put the sample in?” he queried. Steele had a sudden vision of the man at the other end of the line weeping softly into his handkerchief and wondering, “What have I done?”

Together, they figured out the problem—and tracked down the missing item where it was hiding out. Steele’s piece of Mars was a 300-micron particle that had happened to stick at just the worst possible place, so that he and his colleagues had mistaken it for a “full stop” (British lingo for the punctuation mark Americans call a period) at the end of the printed number that identified the sample.

Steele felt a flood of relief. Naturally, in celebration, he and his lab team took their sample, which they nicknamed Chip, to the place where, as Steele liked to say, “all the best British science gets done”—the neighborhood pub.

The word had spread throughout the kingdom—well, at least to Steele’s far-flung circle of friends. One lad drove 250 miles from Preston to be there. The little band set the container holding their microscopic prize in the middle of the worn wooden tabletop and stared at it. “What do we do now?” they asked each other.

They worked out a plan. They didn’t even know which way was “up,” that is, which surface held the mysterious carbonate globules where all the interesting stuff was.

Their next step was to consult Monica Grady, the accomplished meteorite specialist at the Natural History Museum in London, who had taken detailed images of the meteorite. She and her husband, Ian Wright, had worked with Colin Pillinger, Everett Gibson’s collaborator on the
Nature
paper years earlier.

Grady got Steele’s “full stop” mounted properly, carbonate side up, and his group went to town on Chip. They worked on the meteorite through Christmas and New Year’s. It was important to zero in on features similar to those that McKay had focused on, and to match as closely as possible the conditions under which he had operated.

One of the initial criticisms of the McKay group’s claims held that the worm-fossil shapes had actually been created by accident in the laboratory, in the process of preparing samples for the microscope. McKay routinely coated his samples with a thin layer of electrically conducting gold-and-palladium alloy, and if the coating was not uniform, it could have created artificial shapes on the rock.

Using the atomic force microscope, Steele (with colleagues Dave Goddard and Dave Stapleton) applied the same coating and took images of the same areas of their meteorite fragments. While this microscope can magnify up to about 10 million times and distinguish individual atoms, the team used it to map the targeted microfeatures in the sample at the same level of magnification used by McKay—but this time in three dimensions and both before and after the gold-and-palladium coating had been applied. (Quite a trick, requiring considerable work, to find that same spot again: it was 2 microns by 2 microns on a 350-micron sample area. A fine human hair is about 50 microns across.) The device worked something like an old-fashioned phonograph turntable, with a needle arm tipped with a sharp point of silicon nitride that traveled lightly over the surface of the object under study, rising and falling with the tiny topography. The point of a laser beam, in turn, rode piggyback atop the probe, tracking these ups and downs. By measuring the beam’s displacement, the researchers could build a three-dimensional map of the sample’s topography.

Studying areas of the carbonate similar to those described by McKay, both coated and uncoated, they looked for any differences. They found none. Because of the way the images are displayed under the microscope, the globules looked luminous, almost wet, and mottled like a gilded alligator hide. Under the powerful magnification, Steele could see that the gold plating had formed only a slight crazing pattern of gold on the sample surface. Each dot was 7 nanometers across, or tens of thousands of times smaller than the diameter of a fine hair.

He concluded that any artifacts formed as part of this laboratory process were too small to account for what he called “the wormy guy,” the McKay group’s possible fossil. He had effectively ruled that argument out. Now he had a paper to publish, with new information to contribute to the Mars rock debate.

He decided to take his news across the sea to the annual Lunar and Planetary Science Conference in Houston. He had no idea what kind of spectacle he was in for.

The meeting, held in mid-March 1997, was the first chance for the warring camps to face off in one big room and assess the state of play on the Mars rock.

There was a palpable aura of tension and excitement among the more than eight hundred planetary scientists gathered at the Gilruth Center, a recreation complex on the Johnson Space Center campus. Up for discussion were thirty-four new papers concerning the rock. Duck Mittlefehldt was one of the presiding emcees or, some would say, referees. After each set of findings was described, there would be open discussion. At times, the proceeding sounded more like O. J. Simpson’s criminal trial, with opposing arguments, conflicting witnesses, and disputes about contaminated evidence. The arguments ran through hour after hour of the formal sessions and rippled out across the cocktail get-togethers and dinners where so much of the real cross-pollination of science traditionally gets done.

Two members of the McKay team were temporarily out of combat.

In the frenetic and stomach-churning aftermath of the group’s August announcement, David McKay had gone in for a physical, which revealed troubling signs of artery blockage. (David’s father had died of heart failure.) His doctor told him to go get further tests. But he was so consumed with fending off attackers and responding to interview requests that he put the task off through the holidays and into February. He went in for an angiogram just before he and Mary Fae were set to take another pleasurable trip to Japan, where the National Institute of Polar Research had invited McKay to discuss his work.

The procedure, performed on a Friday, showed serious blockage. Three days later, surgeons at the Texas Heart Institute cut through McKay’s breastbone and constructed bypasses for four arteries. As the face-off at the Gilruth Center commenced, he was still recovering.

Kathie Thomas-Keprta was on the verge of giving birth. This left Gibson as the group’s main defender.

Gibson was energized, defiant. His relish for the fight was clear to anyone dropping by his jam-packed workspace during this period. Gibson had ordered custom polo shirts with the insignia “Mars Meteorite Exploration Team,” which he wore proudly and distributed to coworkers.

Around his office—amid journals, tape cassettes, and papers stacked on the floor and tables—Gibson displayed a set of plastic action figures of Warner Bros. cartoon aliens, the Marvin the Martian line. Alongside old air-show posters and an airplane mobile, a tear sheet from the tabloid
Weekly World
blared: “Deadly Mars Rock Virus Infects 4 Researchers.” Rocks were strewn on top of filing cabinets. There were globes of Mars and the moon. A big wall poster showed the comparative sizes of viruses, cells, and such. And, on a shelf, six big loose-leaf binders, titled “Martian Chronicles, Vols. 1–6,” contained his notes and records pertaining to the team’s work on the rock. As the team’s official record keeper, he had in mind that he might write his own book after he left the government.

Over at the Gilruth Center, facing the critics, Gibson declared the evidence of past biological activity in the rock “much stronger now than when we wrote the paper.” He added, “We believe the criticism that has been leveled at us can be answered. . . . This is science in action.” But Gibson was no more combative than some of his assailants.

The main points of disagreement among the combatants were these:

Too Darn Hot?

If the McKay team was right and the mysterious carbonate moons had incorporated the trappings of living organisms, that meant the carbonates with their distinctive Oreo rims must have formed at moderate temperatures. That was presumed to mean no more than about 140 to 170 degrees Celsius (284 to 338F); the upper limits for heat-loving bacteria found in recent years on Earth.

But models developed by various groups put the ranges for the rock’s formation at anywhere from well under 100 degrees Celsius, the boiling point of water at sea level, to 700 degrees or more (well over 1,000 Fahrenheit). To complicate things further, some people would agree that, yes, the temperatures were moderate but there was nevertheless no biology present.

In their
Nature
paper published two years earlier, Romanek, Gibson, and their British colleagues had proffered the initial evidence (based on the oxygen isotopic ratios) that the carbonates had formed from what amounted to a “Goldilocks” broth, neither too hot nor too cold. If the high-temperature model was correct, Gibson argued, the carbonates would have homogenized into an undistinguishable mass, and the organics inside would have disintegrated. Neither had happened.

Joseph L. Kirschvink, of Caltech, and others (including Hojatollah Vali of McGill University, one of the original McKay Nine), took an unusual approach and produced striking—if not conclusive—results.

Magnetic crystals—the iron sulfides that Kathie Thomas-Keprta had detected inside the carbonate globules—are known to retain the signature of any magnetic field present at the time they form, but will lose this telltale imprint at high temperatures, conforming again to the local field as they cool. Kirschvink and coworkers used an ultrasensitive superconducting magnetometer system to detect, in adjacent fragments from a fracture zone in the rock, signs of two distinct magnetic fields aligned at almost a right angle. Presumably the fragments had shifted against each other when a sudden impact fractured the rock.

The researchers estimated that the magnetite grains—and the carbonate around them—could not have been heated above roughly 325 degrees Celsius (617F) and probably not above about 110 degrees C. (230F) in at least the last 4 billion years. If they had been, they would have lost their memory of those opposing magnetic fields.

Arguments about biology aside, this was potentially significant work, showing for the first time that Mars once had a magnetic field. That field, like Earth’s, might have shielded the planet and any emerging life-forms from the deadly “wind” of electrically charged particles that flows off the sun. The Kirschvink discovery also fit with—although it did not prove—the McKay group’s hypothesis that ancient Martian swimmers might have formed little internal compasses to help them navigate in a magnetic field, just as Earth organisms had done.