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

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.