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Steve Squyres Has Hit Feet on Earth and His Eyes on Mars
[In the 6 August edition of Science, the team that put the rovers Spirit and Opportunity on Mars publish their first research from the mission. Read the team's papers and see Mars photos here. Read the full transcript of the interview with Squyres here.]
It was springtime in Florida, and with Mars moving closer to the Earth than it had been in 73,000 years, Steve Squyres would sit on the beach at Cape Canaveral looking up into the nighttime sky and marveling at the planet's rust-red beauty. Still, he couldn't help but worry: Spacecraft carrying the Mars exploration rovers Spirit and Opportunity were scheduled for launch in June, and as lead scientist of the mission, Squyres knew that great challenges and uncertainty still awaited the scientists and engineers who were preparing one of the most ambitious unmanned space explorations in human history.
"Launches are risky," he says now, recalling those days in 2003. "Landing is incredibly risky. We were having all kinds of problems with the hardwareterrifying problems with the hardware, stuff that could've completely kept us from launching because we had fatal design flaws inside the vehicle, things that could result in us leaving a smoking hole in the ground when we got to Mars.
"We had all these problems we were facing and we would go out at night after a day of trying to solve these problems and Mars would just look incredibly distant. You'd sit thereI can remember sitting on the beach at midnight, looking at this thing in the sky. And realizing that two-thirds of the missionstwo-thirds of the pieces of metal that we had flung at that thinghad failed over the years, or the decades. It just looked really, really hard."
It is easier for Squyres to admit to those worries now. The mission that brought the rover Spirit to the Gusev Crater on 3 January and the rover Opportunity to the equatorial Meridiani Planum on 25 January has proven a success. The high-tech rovers and the scientists and engineers based at NASA's Jet Propulsion Laboratory in Pasadena, Calif., have established almost beyond doubt that parts of Mars were, millions of years ago, awash in water. They have found and photographed a mysterious rock now dubbed "Pot of Gold," sort of a geologic whodunit, a rock with features so foreign that it baffles Squyres, a trained geologist, and other team members. The rovers have lasted longer and traveled farther than anyone expected, and still appear to be going strong.
Now Squyres and his team have published their first research in the journal Sciencea total of 11 papers in the 6 August issueand still, every new day brings prospects for further pathbreaking discovery.
In an interview this week, Squyres offered an eloquent, passionateand sometimes humorousdescription of the Mars mission, and of nail-biting behind-the-scenes science and engineering dramas. And from his passion rose insights that touched eternal questions about humans, our impulse to explore, and our place in the universe.
Squyres grew up in southern New Jersey, just across the Delaware River from Philadelphia. It was the time of NASA's Mercury, Gemini and Apollo space programs, and he followed the missions closely, even as he read everything he could about other daring human exploration on earththe deep sea, the Arctic and Antarctica. By the time he enrolled at Cornell University in Ithaca, N.Y., the lure of exploration had drawn him to geology.
"I initially went into geology as a field where I thought I could get paid to climb mountains," he recalls, "a way to do science outdoors with my boots on. And while that didn't work out, it did give me a taste for exploration, doing it myself, that was very appealing."
While an undergraduate in the late 1970s, he enrolled in a graduate course taught by Joe Veverka, who was a member of the Viking science team and who now heads Cornell's astronomy department. Casting about for a research project, he went into what was known as the Mars Room.
"It was the place where they kept all the pictures that were coming back from the spacecraft," Squyres says. "This is before CD-ROMs, the internetwe didn't have much in the way of digital dataand so these pictures were just printed out on big rolls of photographic paper and then they were in this room. So I walked in there figuring I'd take 15 or 20 minutes to go through some pictures and see if I can come up with an idea for a term paper. I was in there for four hours, and I came out of that room knowing exactly what I wanted to do with the rest of my life.
"I'm sitting there going through pictures in notebooks and seeing things that no one had ever seen before. Literally, at that point in time, there probably hadn't been more than 100 people who had actually looked at them. I didn't understand what I was looking at, but the beauty of it was, hardly anybody understood. It was new. It was different. It was the unknown."
By the time he was in graduate school at Cornell, he was an associate of the Voyager imaging science team, analyzing data from Jupiter and Saturn.
Now 48, Squyres is a professor of astronomy at Cornell and the lead scientist on the Mars rover missionand very much a creature of Mars. He has immersed himself for years in its geology, its seasons and light. At times he and the mission team have even had to live by the Martian clock, so that their schedules will more closely correspond to the Martian "sol," which is 39 minutes longer than a day on Earth.
And in speaking with him, it's plain that his imagination roams Mars' peaks, plateaus and craters and has admired its pink sky and towering dust devils. "I've always been intrigued by it, primarily because, alone among the planets, it's the one place where you could imagine life really taking hold," he explains. "I know that if there were any way for me to go to Mars myself, believe me, I'd do it in a heartbeat."
But he cannotnot yet.
The Earth-bound scientists and engineers on the rover team have fashioned Spirit and Opportunity in the likeness of humanshuman scientists and human engineers. There is a tendency to see the rovers as highly talented offspring who still need close guidance.
Each rover looks like a high-tech centaur, with its "eyes" perched on a 5-foot mast above wing-like solar panels and six wheels on the ground. "We gave Spirit and Opportunity 20/20 vision," he explains. "We gave them arms that are very similar in form and function to a human armthat's because the human arm is pretty well designed for the tasks that it has. We gave them the ability to move through the terrain just as we would if we were there, climbing up hills, going down into craters, going across the terrain to get from one interesting place to another. And so they do what we would do if we were there."
If the mission's success is already celebrated, Squyres says the process has been, like most missions of scientific discovery, one of trial and error. Back in the nights when he looked up from the Florida beach at the rusty visage of Mars, he was up against tight budgets and unyielding deadlines. The rover was supposed to be the same size as the lander from the 1997 Mars Pathfinder mission, but it proved to be larger; that meant that the cocoon of huge, inflatable rubber sacs that was to absorb the shock of landing on Martian soil was too small. After some redesign, the cocoon fit, but in a landing test, one of the sacs was punctured. In another test, the lander's parachute shredded because of a flaw.
Even days before launch, a seemingly small electrical problem led to discovery of a design flaw in the pyrotechnic devices which were to be fired to control the landing. "It was terrifyingit was absolutely terrifying. If we had not solved that problem, those rovers could've ended up in the air and space museum instead. It was that kind of stuffMy God! We have to solve this problem or we won't even fly!that we were really focused on at that time."
Perhaps understandably, uneasiness mixed with optimism among the mission crew as Spirit closed in on its scheduled 3 January landing. And yet, all went well. The cocoon deployed, the parachute held, the lander hit the ground, then bounced and rolled for hundreds of yards over the floor of massive Gusev Crater before coming to a stop. The flight team clapped and cheered at news of the landing, and again a few hours later, when Spirit sent its first images of dusty red terrain covered in rocksa terrain similar to that discovered by Pathfinder.
Squyres was thrilled that everything seemed to be working, but he recalls no sense of elation. And perhaps his caution helped him weather the most difficult days ahead.
Eighteen sols into its mission, and three days before Opportunity's expected landing on the other side of the planet, Spirit slipped into a serious state of malfunction. It stopped operating, stopped responding to commands from Earth. Twice the crew sent commands to prompt it just to make a little "beep" that would let the crew know it was still alive. Instead, the commands elicited only more silence.
"It was a very dark time," Squyres says now. "There were a couple of sols there where we'd lost control, and there was a significant chance we were going to lose control for the duration. Opportunity was due to land in a few days, and I'm sitting there thinking, 'Seventy-two hours from now, this whole thing could be over."
But then came a shift: Opportunity came down in the Meridiani Planum on 25 January and bounced and rolled right into a remarkable, shallow crater. Now, at last, Squyres was elatedand incredulous at the panorama captured by Opportunity's cameras. "We scored a 300 million mile interplanetary hole-in-one," he said at the time. A few days later, the mission crew had resolved Spirit's communication and memory problems, and then that rover, too, was running at full strength.
For Squyres, the interplanetary geologist, it was the landscape at Meridiani Planum that was most arresting. It was bizarre. The surface was smooth and austere, with none of the rocks that litter the site at Gusev Crater. Where Gusev appeared to be an old lakebed buried under volcanic crust that had been battered over the years by impacts, the inner slope of Eagle Crater, where Opportunity landed, featured an apparently pristine slice of exposed bedrock.
"This was a magical moment," he said. "We'd never seen anything like itit meant that we were someplace totally different than we'd ever been before. This was rock that you knew had grown up in that neighborhood."
For more than six months now, the rovers have powered across the Martian landscape, taking pictures and analyzing rocks. On some sols, they've traveled only a few meters at a time. But Opportunity has done as much as 140 meters in a single sol. Spirit averaged close to 50 meters a sol in a long drive to the Columbia Hills. Their success is certain to shape future interplanetary exploration, and it may establish the mission as a milestone in the history of human exploration.
Their most significant accomplishment of all?
"Our greatest success on an engineering front is that we have really raised the bar for what we can do robotically on another planet," Squyres says. "We have traveled more than three kilometersin fact, if you add the two vehicles together, I think our total odometry is close to five kilometers now. We're climbing mountains, we're descending into craters, we're really pushing the boundaries of what people have ever done robotically on the surface of another world.
"Scientifically, I think our most significant discovery has to be the evidence for pretty substantial amounts of liquid water at Meridiani Planum," he continues. "And this speaks of an environment in the past on Mars that, at one point in time at least, would have been a very life-friendly and very habitable environment."
However provocative the questions posed by some of the discoveries, though, Squyres takes a firmly neutral scientific approach. He has theories that may explain the mystery rock "Pot of Gold," but he politely declines to share them. And when asked whether he believes there was ever life on Mars, he is again reticent.
"One of the worst mistakes you can make as a scientist is to…wish for an answer to some question," he says. "It can skew your analysis of the data. It can bias your interpretation of results, wishing for something. It's maybe not a good thing to do if you want to find out what the truth is. And I don't have any data that to me point conclusively for or against it, the idea of there having once been or now being life on Mars.
"My inclination is to say, let's use the data we've got to formulate better experiments that may lead us to an answer to that question."
Discovering that life-sustaining water was once plentiful on a planet is an accomplishment, but Squyres thinks that will have no more than a mild impact on humanity. Should life itself be discovered on Mars someday, he expects a different reaction. "If we ever find evidence for life," he says, "that will work a fundamental change in our understanding of our place in the universe."
Squyres and other crew members hope that new missions to Mars in the next decade can begin to address the question of extra-terrestrial life more conclusively. Missions in 2005 and 2007 are already solidified; a mission planned for 2009 may be the first that can take into account the successes and discoveries of the current missions and seek to extend them. And after that, he hopes, will come missions to collect specimens from Mars and return them to earth. Those missions, he believes, can be done by robots and Earth-based crews.
"Getting some samples back and getting them back into the best laboratories on earth and taking them apart molecule by molecule is going to enable a whole range of science that you can't possibly do in situ," he says.
It's possible such a mission could take place while Squyres is still in his prime. But, he says, it's unlikely that he would seek to be the principle scientific investigator again. The current mission has required month after month of exhausting, make-or-break work and enormous sacrifices from his wife and teenaged daughters, who have stayed back in Ithaca while he's been based for the last eight months at NASA's Jet Propulsion Laboratory in California.
"What I'd like to do is continue to participate personally in missions of planetary exploration where I can have a comparable amount of fun but not so much responsibility," he says.
He's already serving as an adviser on future missions, and he's also a member of the imaging team for the high-profile Cassini mission to Saturn. And come 1 September, he and other members of the Mars rover team will be allowed to go home, and to continue their work on the mission from their home institutions, using tele-conferencing, video-conferencing and remote networking for their collaboration.
Even then, though, it's sure that Steve Squyres will remain obsessed with Spirit and Opportunity, the ever-ready rovers. As Martian winter approaches, Spirit is climbing higher into the Columbia Hills near its original landing site; among other things, it is looking for more rocks like "Pot of Gold." And Opportunity is descending deeper and deeper along plunging walls into Endurance Crater.
Both rovers will likely face periods of "deep sleep" through the icy days of winter, preserving their energy at a time of limited sunlight. But assuming that they make it through, the Martian spring will bring new renewed exploration and new discoveries.
Squyres admits that even if the rovers make it through to a second Martian winter, they almost certainly would not survive it. Inevitably, the mission will end; already, that prospect leaves him wistful.
"They're not human, they're machines, but they are machines in which we've put a great deal of ourselves," he says. "Whatever happens, when they die, they will have led long, productive livesfar beyond our expectationsand will have died honorable deaths. And in a situation like that, sure, it will hurt, but I don't think it will be nearly as bad as if they'd died young."
Edward W. Lempinen
6 August 2004
For more information, read the full transcript of the interview with Squyres.