|Is Anybody Out There?|
|Is Anybody Out There?|
If everything goes as planned, by the time you read this a rolling robotic geologist the size of a dune buggy will have completed the first leg of its interplanetary journey—a 208-day, 300-million-mile trek through deep space. Tucked safely inside its lander, the six-wheeled craft, known as Spirit, will have plummeted through a thin veil of carbon dioxide and bounced around in a cocoon of giant airbags before settling upright in an ancient impact crater on the rocky Martian surface. Three weeks later a twin rover, named Opportunity, will (NASA hopes) repeat the process, hurtling down onto a dusty plain on the opposite side of the planet. The two rovers are the latest attempt to penetrate the secrets of Mars, a quest fueled by more than 3,000 years of human fascination with the red planet and, in more recent times, by the existential need to know where we came from and whether we’re here alone.
The Babylonians saw their god of death and pestilence in Mars’s eerie red hue and ambling dance across the heavens. The Greeks and the Romans viewed the planet as a symbol of war and aggression. Both named the celestial body after their gods of war, but it was the Roman deity’s name that stuck. Centuries later, the invention of the telescope refocused attention on Mars and prompted the idea that the planet’s surface was scarred by a network of canals built by intelligent—and apparently constructive—beings. The fantasy, in turn, inspired a century of science fiction. H.G. Wells’s 1898 classic War of the Worlds, for example, dispatched a fierce army of Martians to invade Earth. Ray Bradbury returned the favor in 1950 with his Martian Chronicles, sending humans to colonize a planet already settled by a wise and ancient civilization.
Fact began to catch up with fiction in the late 1960s as the United States and Soviet Union raced to survey Mars. In 1971, the Soviets became the first to land a spacecraft on the planet, but the mission failed after returning just twenty seconds of data. Five years later the United States scored a stunning breakthrough with the Viking mission that beamed back the first photographs ever taken from another planet. The images transported millions to Mars’s rocky, rusty face, thanks in part to Professor of Geological Sciences Thomas “Tim” Mutch, who led the team that designed the camera that took them (see sidebar, opposite page). “It’s transparent, brilliant, boundless,” wrote Mutch, who later became NASA’s associate administrator for space science. “An explorer would understand. We have stood on the surface of Mars.”
Despite Viking’s successes, the mission failed to produce any proof of life on the planet. The search has progressed in fits and starts ever since—but all along Brown faculty and alumni have been at its leading edge. Professor of Geological Sciences James Head ’69 Ph.D., the current godfather of planetary science at Brown, worked as an adviser on several Apollo moon missions and has participated in NASA voyages to Mars, Venus, and Jupiter. James Garvin ’78, ’84 Ph.D. serves as NASA’s lead scientist for Mars exploration and is a driving force behind Spirit and Opportunity. Washington University professor Raymond Arvidson ’74 Ph.D., a veteran of Viking and other Mars missions, helped lead the development of the rovers’ instrument payload. Among the other alumni working on the mission are the science manager, the program scientist, and at least three participating scientists. Brown alumni and faculty helped select the rover project and set its science objectives, and will interpret the data the rovers return. This concentration of Brown-affiliated scientists has led some observers to question whether the school has an undue influence on Mars exploration. “Some people, it’s sad to say, they see this legacy and they react negatively,” Garvin says. “ ‘The Brown people are driving the Mars program,’ [they say]. ‘Should that be the case?’ ”
The rover mission follows a summer during which Mars made its closest pass to Earth in 60,000 years. This orbital dalliance not only provided a rare stellar light show; it also offered a prime opportunity to send more spacecraft. The result is an interplanetary invasion force, which in addition to the rovers includes Mars Express, a European satellite that was expected to enter Mars’s orbit in late December and to deploy a small lander to the planet’s surface on Christmas Day. (Even the Europeans are subject to Brown’s influence. Head and Associate Professor of Geological Sciences John Mustard ’90 Ph.D. collaborated on two Mars Express instruments that will help determine the mineral composition of the Martian surface.)
Nozomi, a Japanese orbiter, was due to arrive at Mars early this year, but the effort was scrapped after a mistake-filled, five-year journey. The experience only confirmed what space explorers know all too well: getting to Mars isn’t easy. And landing is even harder. Two out of every three attempts to reach the planet have failed. The last—1999’s Mars Polar Lander—was felled by a software glitch and faulty wiring. The twin rovers are NASA’s first attempt since to return to the Martian surface.
There is obviously a great deal at stake. The $800 million rover mission comes at a time when NASA is still mourning the death of seven astronauts in last year’s Columbia disaster. A successful mission would provide the kind of morale and publicity coup that the U.S. space agency is desperate for. “Confidence in NASA within the Beltway is at an all-time low,” says American University professor Howard McCurdy, the author of several books on NASA. “If they pull this off and land both these rovers, that is going to be a tremendous boost, and it will spill over to all of NASA.” On the other hand, he adds, “If they lose both of them, I’m not sure Congress would ever hand them another mission. A lot is riding on this.”
LAST OCTOBER, while Spirit and Opportunity were speeding through the solar system still three months from their separate rendezvous with Mars, many of the mission’s scientists and engineers assembled in Pasadena, California, at NASA’s Jet Propulsion Laboratory. The rovers are controlled from the top floors of Building 264, a yellow, eight-story, concrete-and-tinted-glass office building located five miles from the Rose Bowl. The high-rise sits at the foot of the San Gabriel Mountains, near the entrance to the lab’s rambling, 177-acre campus.
Within Building 264, Spirit and Opportunity have each been assigned a color-coded floor. Trim, signs, and chairs in red (for Spirit) and blue (for Opportunity) ensure that exhausted scientists and engineers return to the right place. Just in case, satellite images of each rover’s landing site are also taped to the wall near the elevators. A single mission-control room, filled with engineers communicating through headsets and facing large projection monitors, serves both rovers.
Late on a fall afternoon, two dozen scientists gather for the first of two daily meetings in the large conference room where they do most of their collaborating. Long tables topped with flat-screen monitors divide the room into areas representing the team members’ specialties. Thick black shades cover the windows. Because a Martian day is roughly forty minutes longer than an Earth day, the mission participants push forward their sleep cycles by that amount each day; the shades help with the transition.
“When you’re living on Mars time,” says Matthew Golombek, a leading scientist on the 1997 Pathfinder expedition, “you’re not on the Earth. You’re not going to the bank. You’re not talking to your friends. After thirty [Martian days working] on Pathfinder, we were dead.” Spirit and Opportunity are scheduled to operate three times as long. To complicate matters further, the solar-powered rovers function almost exclusively during the Martian day, and because they are set to land on opposite sides of the planet, the rover teams will work on parallel schedules twelve hours apart.
The team toiling on this hot and smoggy afternoon is focused on one of two prototype rovers that sit a quarter-mile away on opposite sides of a red-tinted, rock-filled indoor sandbox. The scientists are nearing the end of a two-week test designed to train the scientists and engineers to operate both rovers under simulated mission conditions. The drill is turning out to be surprisingly difficult. “Some of these people are world-class field geologists,” says John Callas ’87 Ph.D., the rover mission’s science manager. “They’re accustomed to walking out into a field and using their own senses. Now they’re going to have to rely on the rover and the rover’s senses.”
The exercise, one of a series of such events, is also designed to identify bugs in the operating system and procedures to maximize time during the mission. “When we land, the clock is ticking,” says John Grant ’90 Ph.D., a geologist from the Smithsonian’s Center for Earth and Planetary Studies. “These are solar missions, and they’re not going to operate indefinitely.”
Right now, the scientists are having trouble getting their rover to operate at all. One day during the training period the team failed to communicate with the test rover after an engineer forgot to boost the rate at which data is transmitted to the robot. As a result, the instructions kept getting cut off. For now, no one appears to be panicking. In theory, the more problems uncovered now the better the actual mission should go. But while the scientists and engineers try to learn from their mistakes, everyone working on the mission knows that the simplest snafus can cause catastrophic problems. In September 1999 Mars Climate Orbiter burned up in the Martian atmosphere after a mix-up between NASA and a contractor over the use of feet or meters.
On this day, the mix-up is traced to an error in the instructions sent to Spirit’s earthbound clone. “The rover appears to be healthy,” Michael Carr, a prominent planetary geologist with the U.S. Geological Survey, tells the scientists. “The issue appears to be on the ground.”
Because the rover failed to return any information, the team must decide whether to send the same commands today or devise a new plan. Geoffrey Landis ’88 Ph.D., an expert on solar panels designed for use in space and an award-winning science fiction author, prefers a new plan. But his suggestion to guide the rover to a distant set of rocks is voted down. A consensus emerges to repeat the previous day’s aborted experiment, which involved navigating the rover to a particular spot, using one of its wheels to stir up the soil, and then studying the resulting hole with one of the two spectrometers on the rover’s robotic arm.
The plan places Robert Sullivan ’84, a senior researcher at Cornell, in the spotlight. He was selected for the mission after proposing to use the rovers’ wheels for just such digging. “I know you haven’t slept in thirty-six hours,” Carr says to Sullivan, “but will you take responsibility for this?”
With a plan in place, the scientists split into their specialties to implement it. They cluster around workstations using special software to catalog the actions they want the rover to undertake. Engineers then translate the information into the commands that are actually relayed to the rover. “Telling a spacecraft on another planet what to do is very complicated business,” Sullivan says as he enters a sequence of pictures to be taken by one of the rover’s cameras. “We’ve just got to get good at this. We’re uncovering lots of problems that hopefully we won’t have to deal with once we land.”
THE GENESIS of Spirit and Opportunity can be found in a four-pound Martian meteorite recovered in Antarctica. In 1996, scientists studying the rock, known as ALH84001, announced that it contained traces of ancient bacteria. Although few scientists still believe the dull brown stone holds evidence of primitive extraterrestrial life, the declaration reenergized support for Mars exploration. The following year, when Pathfinder delivered a microwave-size rover to the Martian surface, the next wave of discovery appeared to be under way.
By 1999, however, the Mars program had ground to a halt again. That September marked the loss of Mars Climate Orbiter. Three months later, Mars Polar Lander disappeared during its descent to the surface of the red planet. Those failures, which investigators blamed on poor management, underfunding, and insufficient testing—criticisms that would echo through the 2003 Columbia investigation—prompted NASA to reevaluate its entire Mars program.
“I remember these people staring at me and saying, ‘What would you do?’ ” Garvin recalls. “And I remember saying, ‘We’ve got to go with rovers.’ [NASA’s administrator at the time] Daniel Goldin said, ‘If you want a rover, I want two. Mars is just too tricky.’ ”
The advantage of two rovers is obvious: one of the spacecraft could fail without ruining the mission. But the challenges are formidable. Engineers were forced to build two rovers and two sets of instruments in the time normally allotted for one, which increased the pressure to maximize every dollar spent. Managers also had to recruit and manage twice as many scientists to work on twice the amount of equipment.
“This mission represents an attempt to put a lot of equipment on Mars and do it in a very inexpensive way,” says American University’s Howard McCurdy. “It’s going to be a real test of engineering. It’s going to be real tough.” McCurdy also wonders whether NASA has learned from its past managerial failings. Even Garvin acknowledges that the mission has stretched NASA’s capabilities. “We’ve never developed anything this complicated this fast,” he says. “Thirty-four months to build something that’s never been done before. It’s not normal for NASA.”
Helping to select the right scientists for the mission is Catherine Weitz ’98 Ph.D., NASA headquarters’ program scientist for the rovers. Part of Weitz’s job is also to ensure that the scientists and engineers all work together smoothly—not an easy task, given the passion and egos of everyone involved. Weitz, a small, soft-spoken woman whose NASA badge hangs on a strap reading “Failure Is Not an Option,” is also the project scientist on the European mission, comprising Mars Express and its companion lander Beagle 2—named after the ship that carried Charles Darwin to the Galapagos Islands.
In some ways, the European effort is more ambitious than the U.S. rover project. At its most basic, the goal of Spirit and Opportunity is to roam two landing sites to determine whether or not they once held liquid water. Although water is unstable on the surface of Mars, satellite images of the planet have revealed what appear to be dry river beds, seashores, valleys, gullies, and other geologic structures carved by running water. Vast amounts of frozen water have also been found in the upper layers of soil near Mars’s poles. If liquid water once shaped the Martian landscape, scientists believe that the remnants of the planet’s wet and warmer past might also contain fossilized evidence of life. Even more intriguing are recent discoveries on Earth of microbes colonizing environments once considered too hostile to sustain living creatures. Cold, nearly airless, and bombarded by radiation, the surface of Mars is inhospitable to life as we know it. But some scientists speculate that microscopic bacteria could still be found on Mars, perhaps sustained by an underground hot spring or liquid water trapped beneath a glacier.
So while Spirit and Opportunity will be sniffing out evidence of water, Beagle 2 will look for such direct evidence of life. The clam-shaped lander, which weighs about 150 pounds and measures three feet in diameter, carries instruments to detect evidence of existing or past life, including a mole that can dig up to six feet underground. And there are distinctively European touches. The rock band Blur composed a song for the lander to broadcast upon landing, and scientists will calibrate the lander’s cameras using a dot painting by the artist Damien Hirst.
“It’s sort of the difference with how you play baseball,” Weitz says, comparing the European and U.S. approaches. “Do you want to go for the home run, or do you want to go for a base hit and then wait for the guy next to you to then hit a sacrifice? We’re taking the slower approach to getting to home base, whereas the Beagle 2 team is taking the approach that they need to hit a home run. They’re hoping that right where they land they’re going to find life. And we’re saying that we’re not confident we’re going to find life everywhere, so we want to find where the most likely locations to find life are.” Weitz, who represents a group of U.S. scientists on the European team, insists that, unlike the old days, the various missions are more complementary than competitive. “We’re very interested in seeing what they find,” she says. “And I’m sure they’ll be very interested in seeing what we have.”
HAVING DECIDED to repeat the previous day’s activities, the Spirit team assembles upstairs in Building 264 for the second major meeting of the day. This one brings together scientists and engineers to finalize the rover’s activities for the following day. The process often forces the scientists to compete for mission time, prompting one participant to refer to the encounter as “a gentle but rational gladiators’ brawl.” Despite the problems the team has been running into, everyone seems calm. Tempers flare slightly when a liaison between the scientists and the engineers has trouble understanding the comments of some of the scientists. And the discussion is protracted and time-consuming. Carr expresses exasperation that even though the meeting is devoted to merely copying the commands completed earlier in the day, it exhausts all the time scheduled for it. “I just wonder if during the mission people are going to be so lackadaisical when they don’t get what they want,” Weitz says later. “They’ll probably fight a lot more.”
Under NASA’s ideal scenario, sometime in the early Mars afternoon of January 4, Spirit, traveling at 12,000 miles per hour, will turn its heat shield toward the planet’s surface and enter the Martian atmosphere. Four minutes later, the spacecraft will have slowed to 960 miles an hour and will be slightly more than five miles from the surface. A parachute will deploy to slow it down further. Eight seconds before impact, gas generators will inflate protective airbags, which will surround the spacecraft in what resembles an enormous bunch of white grapes. The package should free-fall the final fifty feet and then roll and bounce for up to half a mile before coming to a stop. The airbags will then deflate, and the lander’s outer petals will peel open to reveal the rover safely tucked inside.
All along, scientists and engineers at the Jet Propulsion Lab will listen for signals tied to important benchmarks in the approach, descent, and landing stages—the most dangerous parts of the entire mission. During the descent alone, Spirit and Opportunity are programmed to send back thirty-six different humming noises. The tones, which should take approximately ten minutes to travel back to Earth, will be picked up by one of the giant antennas that make up the Deep Space Network. From there, the signals will be relayed to Pasadena, and only then will the team members know whether or not the rovers have safely landed. “We’ve got six to seven minutes of sheer agony to go through twice in January,” Garvin says.
The rovers are programmed to spend their first few days on Mars completing internal housekeeping tasks before moving slowly off the landers and onto the surface of the planet. But before they do that, the rovers will snap several panoramic images of the surrounding area, which will be used to assess the safest route off the lander and to select the first rock or outcropping to study.
Scientists involved in the project say Spirit and Opportunity will be the closest thing yet to putting humans on the Martian surface. The rovers’ main eyes, two high-resolution stereo cameras, are located on a mast that stands about as tall as a human being. Each rover also has an arm equipped with a microscopic imager, three spectrometers, and a rock abrasion tool that’s similar to a geologist’s hammer. The rovers have a top speed of two inches per second and are capable of traveling up to forty-four yards a day—nearly half the length of a football field—though it’s unlikely the rovers will wander that far on any given day.
The mission is “the equivalent of sending me with my tool chest to Mars,” Weitz says—except the rovers have more tools. “When I go out in the field I take a rock hammer and a hand lens.” The rovers, by contrast, are equipped with “a thermal imaging spectrometer, all kind of instruments that I’d never be able to carry.”
In addition to giving scientists enough data to study for years to come, a successful rover mission would also set the stage for the next batter in the U.S. lineup, the Mars Reconnaissance Orbiter due to circle the planet in 2006. After that, NASA has scheduled a lander to head for Mars’s north pole, followed by a large long-range mobile lab. The robots on those missions will probably be controlled by brains developed by Ayanna Howard ’93, an artificial intelligence expert at the Jet Propulsion Laboratory. She is working on rovers that can maneuver themselves through rock fields. Sometime in the next decade, NASA also hopes to get a spacecraft to return to Earth with a soil sample.
“Today our knowledge of Mars is at a kindergarten level,” says Garvin, “and the rovers are going to get us into elementary school so we can start moving around. It’s kind of like the Renaissance exploration of the New World.” Rovers and orbiters, he continues, may expand and deepen our knowledge, but they can only take us so far. “Someday,” Garvin says, “we’re going to have to bite the bullet and send people. Machines can’t do everything. There’s a huge opportunity, and with it there’s a huge risk.”
Zachary Block is the BAM’s staff writer.