Читать книгу The Quest for Mars: NASA scientists and Their Search for Life Beyond Earth - Laurence Bergreen, Laurence Bergreen - Страница 9

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.

One day, she sent a postcard to a friend at JPL to say she would be back in a few months. “Do you have any jobs?” she asked, knowing the answer was very much in doubt. The day she arrived back in Ohio, JPL called to say they had a job for her, a good job, if she wanted it, but she would have to make a decision that day or the next. The job opening was on the new Pathfinder project, the next spacecraft to go to Mars. She said she’d take it. Jennifer was fairly skeptical about Pathfinder, but so was JPL. “A lot of people thought it would never work. There were so many things that could go wrong, especially with the Mars environment.” Her new job didn’t seem to have official status at JPL. Even the official Mars program people kept their distance. The development of Pathfinder struck her as a skunkworks, basically. She knew what that meant: if it wasn’t working, they could take it out and shoot it and bury it and no one would be the wiser.

The nature of her job changed as the mission went along. She began by working on software, “but the neat thing about Pathfinder was that once you took a job, it was sort of a ‘where-do-you-fit-in?’ type of thing. People didn’t say, ‘That’s not your job, stay out of there.’ They allowed you to move around, so I ended up doing more integration and testing in the early stages than operations. People were always given the opportunity to move over the borders and learn more and do more.” This open-ended, go-wherever-you-fit-in approach was something very new at NASA, and at JPL, which functioned along rigid, bureaucratic lines of command. The problem with the traditional structure was that if one element was delayed, or failed, or went awry, it brought the entire system to a halt. It became accepted practice for missions to slip several years. People were confined to narrowly defined jobs, and many of their talents and interests went untapped, because they had only a single task to perform. That paradigm didn’t apply to Pathfinder. Things were more flexible. It actually was faster and better and cheaper. This was all new, and very un-NASA.

Not everyone at JPL took to this open-ended approach, but Jennifer did. She became more confident in her various roles, accustomed to change. After her experiences in Russia, she knew not to overreact to situations and to plug along until she found a solution or failed miserably. In time she developed an informal network of specialists and advisors she could trust, her go-to people. The Pathfinder cradle-to-grave approach helped a lot. People came on board at the beginning, when the hardware was delivered, and they stayed all the way through to the end of operations. On the typical NASA mission, the person responsible for delivering the hardware would say, “I’ve delivered my hardware on time,” and walk away. If the hardware happened to be a camera, and it took pictures, they felt they had achieved their goal. They didn’t care if it was impossible to operate, or if it didn’t get the right pictures. But if you worked on Pathfinder, you had to undergo a mental shift. If you designed your component incorrectly, if it was difficult to test or to operate, it was still your problem.

It was difficult to explain the new thinking, Jennifer realized. You had to experience it for yourself, and then it could make a huge impact. You would become committed to the ultimate goal, whatever it was. In Pathfinder, the goal was to get to Mars quickly and cheaply, and to get a rover to function on the Martian terrain. Things worked in a sort of non-systematic way because people attacked problems where they saw them. Eventually, they generated procedures, and she wrote the documentation, but this was not a document-heavy mission, like most NASA missions. She sat down with a couple of other people, and they asked, “What are the most likely contingencies? What’s our nominal plan at the big-picture level?” She realized this could be a wonderful opportunity to participate in the exploration of space, and that idea pleased her greatly. “I feel like God has blessed me in my career,” she once wrote, “and I would like to glorify Him by exploring His incredible creation.” So the missionary had a new mission, but even as a scientist, especially as a scientist, she still devoted herself to God.

The Pathfinder mission originated in a speech given by President George Bush in 1989 to commemorate the twentieth anniversary of men – American men! – landing on the moon. NASA was in the doldrums at the time; and the occasion of the speech seemed to point up how little it had done since the halcyon days of Apollo. The Challenger disaster, which occurred more than three years before the anniversary, still loomed; when people thought of NASA, they didn’t visualize Neil Armstrong jumping onto the surface of the moon, they thought of the faces of the parents of Christa McAuliffe, the school teacher who rode aboard the Space Shuttle, looking in disbelief at the Y trail left in the sky by the catastrophic explosion.

Along came George Bush, discussing the future of space exploration. The demoralized NASA contingent could scarcely believe what they heard. Did the President mention “the permanent settlement of space”? Yes, he did. Did he also say it was time to travel “back to the moon, back to the future, and this time back to stay”? Indeed, he said that, as well. But surely he could not have said, “And then, a journey into tomorrow, a journey to another planet: a manned mission to Mars.” Yes! The President said that, too. Mars. The NASA bureaucrats began to ask themselves: how much was all this going to cost? No one thought you could go back to the moon and on to Mars for under 400 billion dollars; the tasks might require twice that amount. NASA’s annual budget at the time was around 13 billion. Where would the money come from? Interestingly, few doubted that the technology existed to send people to Mars, or that it could be developed quickly; if NASA had the money, they could get the job done.

George Bush’s remarks evoked John Kennedy’s famous speech in which he charged NASA with the duty of sending men to the moon. Without realizing it, Bush tapped into the agency’s other obsession, reaching Mars, an obsession that had begun in the mind of its ace rocket engineer, Wernher von Braun, during World War II. Von Braun, a member of the Nazi party, and a favorite of Hitler’s, had helped to design the V-2 missile. When he became disillusioned with the Nazi war machine, the Gestapo arrested him and sent him to jail. In his cell, he turned his attention to interplanetary travel, and Mars in particular. And it was in these strange and harsh circumstances that the kernel of what would become the American effort to explore Mars was born. In May 1945, von Braun and over a hundred other German rocket scientists surrendered to the Allies. They were swiftly transplanted to New Mexico to continue their work on rockets, this time for the United States. The German V-2 became the prototype of a new generation of American missiles, and on the strength of his engineering accomplishments for the Nazis, von Braun quickly established himself as the chief architect of the American space program’s booster rockets during the 1950s and 1960s; his designs were responsible for getting American men to the moon.

Throughout his career, von Braun was mesmerized by Mars. He published his plan to send people to Mars, the one he had conceived in jail, as a long magazine article titled “Das Marsprojekt,” which was translated into English. In 1953, it appeared as a book in the United States: The Mars Project. It became a classic, but this was not science fiction; The Mars Project contained no inspiring rhetoric about humankind’s greatest adventure. It was a how-to manual, a master plan for getting people to Mars. He used a simple slide rule to make his calculations, and its pages contained his blueprint for the actual mission, using available technology. “The logistic requirements for a large elaborate expedition to Mars are no greater than for those for a minor military operation extending over a limited theater of war,” he wrote. The key to reaching Mars, he believed, was sending a flotilla of spacecraft. “I believe it is time to explode once and for all the theory of the solitary space rocket and its little band of bold interplanetary travelers. No such lonesome, extra-orbital thermos bottle will ever escape Earth’s gravity and drift toward Mars.” Instead, in von Braun’s vision, “Each ship of the flotilla will be assembled in a two-hour orbital path around the earth, to which three-stage ferry rockets will deliver all the necessary components. Once the vessels are assembled, fueled, and ‘in all respects ready for space,’ they will leave this ‘orbit of departure’ and begin a voyage which will take them out of the earth’s field of gravity and set them into an elliptical orbit around the sun … Three of the vessels will be equipped with ‘landing boats’ for descent to Mars’s surface. Of these three boats, two will return to the circum-Martian orbit after shedding the wings which enabled them to use the Martian atmosphere for a glider landing. The landing party will be trans-shipped to the seven interplanetary vessels, together with the crews of the three which bore the landing boats and whatever Martian materials have been gathered. The two boats and the three ships which bore them will be abandoned in the circum-Martian orbit, and the entire personnel will return to Earth orbit in the seven remaining planetary ships. From this orbit, the men will return to the earth’s surface by the upper stages of the same three-stage ferry vessels which served to build and equip the space ships.” It was a grand scheme, and it became the template for NASA’s plans to send people to Mars, a goal von Braun thought could be accomplished by the late 1970s.

Bush’s speech endowed von Braun’s dormant plan with new life, but the prospect of returning to Mars raised new questions, as well. If NASA planned to send people to Mars safely, scientists needed to know much more about the Red Planet. If there was life on Mars, what form did it take? Was it dangerous to humans? Could it devastate the Earth if astronauts brought samples home? How severe were the effects of radiation? And, most important, was there water on Mars? The presence of water would dramatically enhance the prospects for finding life, but more than that, water meant it would be possible to manufacture rocket fuel, oxygen, and other human essentials on Mars.

Three years after Bush’s speech, in 1992, NASA announced plans to send between twelve and twenty small landers to Mars. They would fly frequently, and they would take advantage of new equipment, especially computer technology, to explore more effectively. The new program went by the name of Mars Environmental Survey – MESUR, in NASA-speak. The agency then announced another planetary program, Discovery, with similar goals; it was a nice instance of the right hand not knowing what the left was doing. Eventually, the two programs merged into one trial program: Pathfinder. It was going to be fast, it was going to be cheap, but no one knew if it would be better than previous planetary missions. Unlike most NASA missions, which are built and often operated by a private aerospace contractor such as Lockheed Martin, Pathfinder was an in-house project, designed, built, and operated by JPL. It was meant to embody JPL’s prowess as NASA’s robotics center, and that posed an embarrassing problem.

It had been a generation since Americans had landed a spacecraft on Mars. The old guard was gone, and few around JPL or NASA remembered exactly how that trick worked. Some scientific data had been preserved, though not completely, along with thousands of Viking images, but there was little documentation of the mission’s engineering accomplishments. Rob Manning, the young leader of Pathfinder’s Entry, Descent, and Landing team, sought veterans who could tell him what they had done on Viking, but many had died, and others had retired. JPL pulled a few of the old grizzlies out of retirement to help assemble a unit capable of developing a lander, and they went to work under Manning.

The idea behind Pathfinder, to develop and build a new spacecraft on a drastically reduced schedule and budget to land on the surface of Mars, sounded like a losing proposition to many at JPL, given the risks involved in getting there. Just setting their ship safely onto the surface posed difficult engineering problems. The spacecraft travels at about 17,000 miles an hour as it reaches Mars. Then it must slow to nearly zero miles an hour so that it does not vaporize in the Martian atmosphere or crash into the surface like a meteorite. The Viking solution to this problem, an expensive and cumbersome one, employed powerful, heavy thrusters capable of guiding the spacecraft gently to the surface. There was no money for that kind of extravagance with Pathfinder. Instead, Pathfinder’s engineers planned to wrap the lander in a protective bubble, place the bubble inside an aerodynamic cone, and parachute it through Mars’ thin atmosphere to the surface, letting the cone peel off in sections. Then Pathfinder would bounce around the surface like a big hi-tech beach ball. If all these cushioning devices worked properly, Pathfinder would still be in once piece when it came to a stop. This follow-the-bouncing spacecraft approach was profoundly troubling to conservative NASA engineers, but Manning casually accepted the risks. “Pathfinder is just a rotating bullet with nothing controlling it. This cone shape produces some unstable results – not so unstable that it’s devastating, but you live with that.” When he presented his landing scheme to NASA’s review board, they were, he said, “skeptical – borderline hostile, as they should be. They were paid to challenge everything. So it was a big deal when we deviated from the Viking heritage.”

Even if it landed safely, Pathfinder wouldn’t sit still on the surface of Mars, taking measurements, as the Viking landers had. It would carry a rover designed to roam across the surface, functioning as a twelve-inch-tall geologist. This was not a new idea; for decades, NASA had explored the possibility of sending a rover to investigate Mars. “My most persistent emotion in working with the Viking lander pictures was frustration at our immobility,” Carl Sagan recalled in 1980. “I found myself unconsciously urging the spacecraft at least to stand on its tiptoes, as if this laboratory, designed for immobility, were perversely refusing to manage even a little hop. How we longed to poke that dune with the sample arm, look for life beneath the rock, see if that distant ridge was a crater rampart … I know a hundred places on Mars which are far more interesting than our landing sites. The ideal tool is a roving vehicle carrying on advanced experiments, particularly in imaging, chemistry and biology.” He outlined, with his usual visionary fervor, a rover-based mission very much like Pathfinder. “It is within our capability to land a rover on Mars that could scan its surroundings, see the most interesting place in its field of view and, by the same time tomorrow, be there … Public interest in such a mission would be sizable. Every day a set of new vistas would arrive on our home television screens. We could trace the route, ponder the findings, suggest new destinations … A billion people could participate in the exploration of another world.” At the time he wrote those words, they sounded like the vaguest hyperbole, but Pathfinder and the Internet would make his outlandish prediction a reality.

Although a rover seemed like a nifty idea, it was untried. The later flights in the Apollo program had taken along a dune buggy to traverse the powdery surface of the moon. The astronauts could steer and stop the rickety lunar flivver at will. The difficulties involved in guiding Pathfinder’s rover across the surface of Mars by remote control seemed insurmountable. What if the rover didn’t emerge from the beach ball after all that bouncing? What if it got stuck on a rock or a crevice or sank into the talcum-powder-fine Martian soil? What if the beach ball landed in inhospitable terrain? What if it landed on the wrong part of Mars, where it couldn’t receive signals from Earth? And yet, if it avoided all these pitfalls and worked, the rover would provide a whole new paradigm for exploring the surface of Mars, because JPL had visions of building bigger and better rovers in years to come, until they reached the size of small trucks. But most people guessed a small rover would never work, not with the two million dollars allotted for its development.

A debate sprang up over the best way to control the rover, and, given the personalities involved, it quickly escalated into a dispute over technological theology. Tony Spear, a veteran engineer at JPL, believed the most reliable and cheapest way was to tether it to the mother ship. The other approach, advocated by Donna Shirley, was to control the rover remotely, but that meant designing or finding a new radio system, one that could tolerate the extreme fluctuations in the Martian environment, including fluctuations in temperature between the rover and the lander.

Donna Shirley was a controversial figure around JPL. When her name was announced as the Pathfinder mission director, a few cheers went up, but only a few; there was also consternation. Tony Spear, the Pathfinder project manager, was nowhere to be seen during the announcement, and Donna took his absence to indicate his lack of support. She could live with that. She thought the apparent indifference had to do with the fact that she was a woman, but she was accustomed to handling that problem. Donna had been with JPL since 1966, when very few women filled responsible posts there; during her years there, she married, raised a daughter, and got a divorce. At work, she was relentlessly cheerful, almost, but not quite, to the point of bullying, and she was a world-class talker. Many bureaucrats and scientists at NASA were camera shy, but when a television crew appeared at JPL, there was Donna Shirley in her bright red dress, flashing her assertive smile, prepared to discuss in her folksy Oklahoma twang just about anything. Her appearance was perfect for television. TV producers were delighted to interview the ebullient Donna Shirley instead of a pale male attired in the gray suit, gold-rimmed glasses, and neat mustache favored by the upper echelons at NASA. But, while being interviewed, she occasionally appeared to take credit for the work of a great many NASA scientists and engineers toiling anonymously, and that did not work to her advantage.

Her detractors said she really didn’t know her science well, but she made her lack of expertise into an asset because she had no scientific agenda, nothing to prove. She was content to bang heads together cheerfully and say, “Look, guys, now we are going to do it this way.” To the increasing number of women coming out of graduate school to work for NASA, she became a symbol. These younger women liked to tell a story about the time Donna Shirley attended a launch party at Cape Canaveral. As usual in those days, she was the only woman present. A guitarist singing a bawdy song, accompanying himself on the guitar, stopped dead when he saw her. She took his guitar and completed the song herself, delighting everyone. That was great, as far things went, but she didn’t realize there was a tradition at these launch parties that a woman – a hooker, basically – was paid to show up and pull a stunt like that. One of the men assumed Donna had been hired for the occasion, maneuvered her into an alcove, and grabbed her. “I didn’t exactly deck him,” she said, “I just hit him on the nose.”

Working on Pathfinder, she saw her team of engineers and scientists as a large family, her family. To her credit, she encouraged everyone to talk to everyone else, if only in self-defense, and she always smiled and radiated optimism. Most found it impossible to bear a grudge for long in the face of such cheerfulness; it was too exhausting to oppose her. Still, she wanted her radio-controlled rover for Pathfinder, and Tony Spear, the project manager, did not. “In his position, I wouldn’t either,” she said, “because he had the impossible job of landing on Mars for a fraction of what it cost the last time we landed. He had no idea how to do it, and here’s this parasite coming along, giving him nothing but trouble. What I did was to convince the scientists that we really could do useful work with the rover. That was number one. Number two was to convince Tony that we really could fly without damaging his mission.” When Donna presented her case to NASA’s review board, one member, Jim Martin, the former Viking project manager, insisted a Mars landing could not cost less than Viking had. As for the rover, “he thought it was terrible.” Donna and the rover team persisted, building better iterations of the rover and demonstrating they worked as advertised. “It became a very powerful selling tool,” she realized, and eventually, to everyone’s surprise, it turned into the mission’s raison d’être.

If Pathfinder’s engineering was, ultimately, carefully weighed, the mission’s science component tended to be rushed, improvised, an afterthought. Plenty of scientists were eager to participate in the new Mars mission, but they needed time and money to formulate, conduct, and analyze experiments. Pathfinder didn’t work that way. At the last minute, for instance NASA stuck a couple of stereographic cameras on the lander and another camera on the rover. These weren’t your standard television cameras; they used a technology known as a Charge Couple Device. The CCD reproduces light very accurately and is especially useful for spectroscopy, which reveals more than the naked eye can see by measuring which wavelengths of light are absorbed, and which reflected, from an object. They were useful, but they were not capable of sending back the sparkling, gorgeous images returned by Viking twenty years earlier. Pathfinder also carried an Alpha Proton X-ray spectrometer to detect the composition of Martian rocks, and a weather mast to measure the Martian temperature and atmospheric conditions. Every so often, Pathfinder would collect the weather mast’s data and return it to Earth, so for the first time it would be possible to obtain accurate weather reports from the surface of Mars. Everyone agreed the weather mast would be a terrific experiment, if it worked. It looked like Pathfinder had a chance to become a real mission, after all.

Manning’s team conducted early Pathfinder landing tests at a NASA facility in Cleveland, Ohio, which featured a large vacuum chamber. Within, girders, lava rocks, and wood simulated the Martian surface. They dropped Pathfinder in its protective bubble onto the sharp objects and observed the result.

R-r-r-r-r-r-rip!

“The first time we did it, we had a tear the size of a human being,” Manning said. They took it back to the lab, fixed it up, and dropped it again.

R-r-r-r-r-r-rip!

They tweaked it and tried again. R-r-r-r-r-r-rip! … R-r-r-r-r-r-rip! … R-r-r-r-r-r-rip!

The trials went on like that for months; they were “total disasters,” said Manning, and NASA nearly canceled the mission. Late in 1995, the Pathfinder team redoubled its efforts. The engineers adjusted the spacecraft’s small guidance rockets. They modified the shape of the sphere contained inside the protective beach ball. They had been imitating the Russian model, which was spherical and consequently difficult to manufacture; now they adopted a tetrahedron, which was easier to manufacture. They toyed with the air bags protecting the tetrahedron, trying one deflation strategy after another, getting incremental improvements. Gradually, they came to feel more confident about Pathfinder. They did have one advantage: because the gravity of Mars is less than half of Earth’s, the spacecraft would endure less wear and tear. “We always worked in terms of the mass, and the mass kept getting bigger and bigger,” Donna said. “That meant the mechanical parts had to be heavier because they were supporting all of this additional structure. The mission design people came to the rescue. They said, ‘Okay, if we’re going to fly into the atmosphere of Mars, there’s a corridor we have to hit. If we go in too shallow, we’ll just skip out of the atmosphere and keep on going. If we go in too deep, we’ll burn up on entry, or we won’t have enough atmosphere to slow down before we hit the surface.’ So there’s a narrow range of angles at which you can enter the atmosphere, and that takes some really accurate shooting by the navigators. So the navigators heard this and said, ‘Okay, if we can shoot more accurately and give up some of our margin for error, we can let the spacecraft have more mass.’” Now the engineers were able to add small thrusters that would slow Pathfinder during its descent to the surface.

The mission was still alive, but the development of a decent, affordable rover still posed engineering problems. JPL had to devise a nimble mechanical creature that could scale small barriers and climb over rocks, like a little tank. To complicate matters, it would take twelve or fifteen minutes for a radio signal to travel from the Earth to Mars, which eliminated spontaneous, real time commands. “If you’re looking through the rover’s eyes, and you see a cliff coming, and you say, ‘Stop!’ it’s too late – it will be over the cliff, so it has to be smart enough to stay out of trouble,” Shirley said. In addition to negotiating the Martian terrain, which was in many details unknown, the rover had to keep its solar panels in position to receive sunlight, or it would lose power and die.

Attempting to meet these requirements, JPL devised variations on a theme. They built a rover the size of a small truck, and they built one just eight inches long, nicknamed “Tooth.” They built a mid-sized rover called Rocky, which, when tested in the desert, actually did things required on Mars, such as scooping up soil. Rocky went through various iterations until it weighed just fifteen pounds, yet negotiated the kind of obstacles and terrain that geologists expected to find on the surface of Mars. It could perform simple experiments, and it appeared sturdy enough to withstand the rigors of landing on the Martian surface and bouncing around inside a beach ball.

The development of Pathfinder’s components took place in a knowledge vacuum, because the engineers and scientists didn’t know exactly where they were going on Mars or what to expect when they got there. From a spacecraft’s point of view, Mars presents a landscape of treachery. The team expected to receive finely detailed studies of the surface from Mars Observer, the billion-dollar spacecraft launched on September 25, 1992. It was supposed to reach Mars the following August, when its cameras would send back pictures of the Martian surface with much higher resolution than Viking had captured in the seventies, and those pictures were supposed to give JPL a well-informed notion of where to land their bouncing beach ball. Just when Mars Observer was to begin orbiting around the Red Planet, JPL lost the signal, and the spacecraft was never heard from again. There was speculation that a fuel line had frozen and ruptured, and the spacecraft went out of control, but nobody could say for sure – nobody, that is, but fringe elements, who concocted some fairly creative theories. There was the “Hey! That was no accident” scenario: NASA deliberately destroyed the spacecraft because it had detected signs of intelligent life on Mars. And there was the “Mad Martian” scenario: Mars Observer had been destroyed by sophisticated Martian weapons whose existence NASA conspired to conceal from the American public.

Within NASA, scientists feared they had lost their chance to return to Mars. Shortly after Mars Observer disappeared, Dan Goldin journeyed to the Goddard Space Flight Center in Greenbelt, Maryland, to rally the troops. Although Goddard is only a short commute from NASA headquarters in Washington, D.C., the head of NASA is not in the habit of dropping in, so his presence signaled a major announcement. For many scientists, it was their first close-up look at the man whom George Bush had appointed in 1992 to run the agency. At Goddard, he reminded the scientists that NASA attempts to do difficult things, risky things, and the possibility of losing a spacecraft was an ever-present hazard, but the risk didn’t mean the mission wasn’t worth doing. They would continue to explore Mars. Conditioned to regard managers as antagonists, the scientists were impressed.

Under Goldin’s leadership, the loss of Mars Observer provoked NASA to hone and intensify its Martian agenda. The agency decided to launch a pair of missions to the Red Planet approximately every two years, whenever the orbits of the two planets brought them into a favorable alignment, beginning in 1998. Each mission would have a distinct identity and purpose, but, taken as a whole, they would culminate in sending humans to the Red Planet. What sounded like a rather vague statement of intent acquired sudden conviction in August 1996, with the announcement of possible fossilized life in ALH 84001. Goldin suddenly began pressing JPL and the scientists to make specific plans to bring a sample of Martian soil back to Earth to continue the search for life. Donna Shirley and the other managers said they couldn’t do that much on their subsistence budget.

Returning a sample of Mars to Earth is a complex, costly, and hazardous undertaking. You send two spacecraft – a lander and orbiter – to Mars. The lander scoops up enough soil to fill a can of Coke, and then it must launch itself from the surface of the Red Planet and guide itself to a rendezvous with the orbiter. NASA has never done that before – launched a spacecraft from a distant planet. If that part of the mission succeeded, the orbiter would bring the sample to Earth, where new hazards would arise – for instance, the sample might be dangerous or even lethal to terrestrial life. The safe handling, testing, and decontamination of the sample would amount to a large project in itself. NASA confronted a similar problem with samples of the moon in the sixties, and set up an elaborate, isolated lunar laboratory at the Johnson Space Center, where moon rocks were analyzed with great care by technicians wearing long rubber sleeves and working behind glass until the rocks were found to be harmless. There is much greater concern about possible harmful effects of Martian soil because of the greater likelihood of life on Mars. The quarantine will likely be extreme and long-lasting. When you talk about a sample return, you’re talking about spending billions of dollars and placing the lives of everyone on the planet in some degree of jeopardy. You’re talking about a mission almost as complicated as a human mission to Mars.

NASA expanded its string of Mars missions into a more formal, and better-funded, program of exploration. “The Human Exploration people at the Johnson Space Center came along and said, ‘Okay, we want to fly humans to Mars.’ Dan Goldin set 2018 as a date, but the Johnson Space Center said, ‘Well, we think it should be earlier than that. We’d like to do it by 2011,’” Donna Shirley said. “To decide whether to send humans to Mars by 2011, you need to make a decision by about 2005 that you are going to invest in doing that, and you need to have the information necessary to make the decision. The only way to get the answers by 2005 is to fly by 2001.” Just when it looked as though Mars might get a lot more money, Congress realized that the International Space Station was generating huge cost overruns, and it sucked up money that might have gone to human Mars exploration.

Goldin didn’t give up on the idea of sending people to Mars. He directed scientists at NASA to make plans for an eventual human mission. Although the project was unfunded and unofficial, it was real enough, and the scientists and engineers went at it with the zeal of true believers. Their enterprise went under vague names, such as Beyond Earth Orbit (BEO) and Human Exploration and Development of Space (HEDS), names that meant different things to different people, and wouldn’t upset Congress. But to those within NASA, the names meant one thing: sending people to Mars. So a lot was riding on the success of the little Pathfinder mission; the implications went far beyond the success or failure of its experiments. It was, potentially, the first step in the most ambitious exploration in history, but few outside of NASA realized that.

The loss of Mars Observer meant Pathfinder’s site selection team was forced to rely on twenty-year-old Viking data. Since Pathfinder was designed to plummet to the Martian surface, it would not be able pick and choose a landing site as Viking had. The site would have to be selected in advance, and it had better be good. A lot of the responsibility for selecting a site fell to Matt Golombek, a young geologist. If you can recall the kid in the seventh grade who always seemed a couple of steps ahead of the teacher, let alone the class, and who was wiry and agile and had a way of laughing off anything that bothered him, you have a sense of Matt Golombek. He came to the agency from Rutgers and the University of Massachusetts as one of the new generation of planetary geologists that included Maria Zuber and Jim Garvin. “You only do this because you love it. It’s not like you’re going to get rich or famous. You’re especially not going to get rich,” he says. Although he reports to work at JPL, which is a government facility, he is, like everyone else there, technically employed by Caltech. It’s a peculiar arrangement, which he facetiously likens to a “money-laundering scheme to lower the number of civil servants.” Matt maintains a certain skepticism concerning government work. “You know what they say about civil servants, don’t you? They’re like rusty old guns. They don’t work, and you can’t fire them.”

Despite his youth, Matt brought with him long experience in Mars exploration. “I was the pre-Project Scientist on all the Mars missions before Pathfinder for ten years, and there was a whole string of them. I was brought in originally with something called the Mars Rover Sample Return, which was actually a politically motivated study to work with the Russians, which didn’t go anywhere.” This was followed by assignments on other luckless missions, including Mars Observer. “I think one of the reasons they assigned me to Pathfinder as the Project Scientist was that I was young. Part of their thinking was, ‘Well, it doesn’t matter who we appoint. It’s not going to mean anything.’ I wasn’t sure I even wanted the job, because the mission was an entry, descent, and landing demonstration that would have little or no science of benefit to anyone. What the hell do you need a Project Scientist for? There’s no science, right? I mean, Pathfinder’s main goal was to land safely, period.”

To achieve even that limited goal, he spent two years mastering every detail of the choices before making his recommendation. The pixels in the old Viking images concealed many potential hazards. “Imagine if you looked at an image to select a potential landing site, and the smallest you see is the size of a football stadium, and you are worried about things that are the size of a meter,” Matt said. “All we had was very coarse, low resolution remote sensing information about Mars, yet we had to guesstimate that the place we would come to rest would be safe, and that the rover could travel out on it. That’s a very difficult job. It was a two-and-a-half year process. We did an exhaustive study of the options, of cost, and of the kind of science you could get at different places.” He had to factor many subtle requirements into his choice. He looked for a spot where Pathfinder’s solar cells would supply power, and where the antennae could communicate with Earth as often as possible. He wanted an area free of mesas, which would confuse Pathfinder’s navigational system. Those and other constraints eliminated ninety percent of the surface of the planet. Geological factors eliminated a number of other tempting targets; if an area was too dusty, too cavernous, or too rocky, it was eliminated from consideration.

There was something else on his mind. What was the point in going all the way to Mars only to land in a dried-up, featureless lake bed and watch the rover go round and round? Why not use the tools they were bringing, the Alpha Proton X-ray spectrometer and the cameras? Why not make Pathfinder a science mission as well as an engineering mission? “Wait a minute,” he told anyone who’d listen, “we can actually do science.” Perhaps the mission would need a Project Scientist, after all. Matt saw his chance to push against the system and work with the engineers to make room for science. For Pathfinder to accomplish anything significant, it would have to land in a place with attention-grabbing rocks – rocks that would speak volumes about Martian geological history, especially the presence of water, rocks that were big, but not too big. He didn’t want boulders, for instance, and he didn’t want pebbles, either. He wanted, so he said, a “rock mission.” He wanted a “grab bag, a smorgasbord, a potpourri of rocks.” He wanted sermons in stone.

Everyone at JPL recognized that Matt was a very good scientist. Now he demonstrated that he was a very good scientific operator, as well. His gift for caustic repartee concealed considerable shrewdness; depending on his purposes, he could be engagingly cynical, or firm and cool. He was persuasive with his colleagues, lacing his remarks with irony, imparting to all those around him the intoxicating sense that they were being drawn into some grand cosmic joke. Nothing intimidated him, least of all NASA’s bureaucracy. NASA was a bunch of civil servants – c’mon, people, don’t you see the joke in this situation? It was a racket. Caltech was another racket, as was JPL. Then there was the science racket, the engineering racket, the budget racket, and of course, the Mars racket, and they were all susceptible to lobbying and influence if you knew where to apply pressure, which came down to motivating people to do something different. “The hardest part of going to Mars,” Matt once told me, “was getting everyone working on Pathfinder to march in the same direction.”

Unlike most scientists, he was good with the engineers; he appreciated the difficulties they faced. Scientists and engineers often develop adversarial relationships: scientists usually display scant patience for the difficulties of building and operating the instruments, and engineers tend to regard scientists as impractical, arrogant, impossible to please. Stepping into the midst of the fray, Matt pushed back on the scientists, knocking down the number of experiments, and he convinced engineers they could do things they wouldn’t have thought possible. That was a formula for a very successful manager of space science. “You almost have to turn yourself into an engineer,” he said, “because you have to understand what your spacecraft’s doing. Your dominant job as a Project Scientist is to make sure they don’t engineer the science off the mission. It’s not that engineers are dumb, they’re doing the best they can, but they don’t necessarily think about science. And so you sit through interminable meetings waiting for the one silly thing that will pop up and threaten the science. I mean, it’s crazy! The other aspect, once you get the mission going, is that you have to lead the science team. You have to show them where you’re going. What’s really important? How do you allocate resources? How do you keep people’s egos from getting in the way? That’s very tricky.”

He became adept at building a consensus around the selection of a site. He led a site selection workshop at the Johnson Space Center in Houston, fielding ideas from the entire Mars community. They whittled the choices down to about ten, which Matt put on a large, complicated diagram called “The Chart from Hell.” After much study, Matt, working with another geologist, Hank Moore, concentrated on a Martian basin named Chryse Planitia – Chryse Plain. Within Chryse there is an outflow channel called Ares Vallis, the geological legacy of a huge, ancient flood that deposited interesting and varied rocks on the surface. The diverse rocks were the greatest attraction, as far as he was concerned. The area’s sheer size made it very appealing. Pathfinder, in addition to all its other uncertainties, could not make a carefully predetermined landing; if all went well, it would land somewhere within an ellipse 60 miles wide and twice as long. Matt fretted over the temperature range of Ares Vallis, over the distribution of rocks, and especially over the amount of dust blowing around. If you’ve ever come into contact with terrestrial lava dust, you immediately understand the problem. It’s gritty and irritating and clings to the fingers. Martian dust, made from powdered lava, is similarly fine and gritty. It relentlessly clogs machinery and obscures solar panels.

To get a better idea of what Pathfinder might encounter if it landed in Ares Vallis, Matt used an Earth analogue – not Iceland, in this case, but the Channeled Scabland in the state of Washington. This desolate region was formed during a huge flood about 13,000 years ago; the turbulent water redeposited rocks across a flat plain, just as Matt believed had once occurred in Ares Vallis on Mars. The Channeled Scabland is much smaller than the Martian site he was considering, and tufts of grass spring from the soil, but geologically, it is remarkably similar to Ares Vallis. He took several field trips to the Channeled Scabland, and even brought along the rover to see how it would fare on the rock-strewn terrain. It ably negotiated the varied surface, and he figured he had finally found his landing site. Ares Vallis was safe, it was geologically interesting, and it was, he hoped, not too dusty.

NASA’s review panel considered his choice. “You’re going to go back there and kill the spacecraft – and kill your career,” they said, but Matt would not be intimidated. He had seen the results of Pathfinder tests in even worse conditions than it would encounter on Mars, and the spacecraft had survived. “We ended up making the most robust lander that’s ever been designed to land on a planet. Pathfinder could land anywhere,” he told the panel. In the end, Matt got his way, and his landing site on Ares Vallis, but his career would ride on Pathfinder’s fortunes.