Do you think we will find evidence of life, past or present, on Mars?
S: I don’t have an opinion on that. In fact, I believe firmly that the worst thing a scientist can do is to have a preconceived notion about what you are going to find because it can skew your interpretation of the data.
On a philosophical note, what does it matter whether or not there is life on Mars or somewhere else in the universe?
S: You’re right, it is a philosophical question. If I can’t convince you that learning whether or not life is common in the universe or that learning how life came about is an interesting fundamental problem that people should care about, then nothing else I say is going to make any sense. If you do accept that premise, looking for whether or not there was ever life on Mars is important in two ways. Right now we have one example of life: us. We are it. If all you have is one example of something like this, you have no way of knowing how common, how rare, how unique it is throughout the universe. But if we were able to show that life had arisen independently on two different worlds, just within this one solar system, the idea of it being common throughout the universe is an easy one to accept. That is one reason. The other concerns the question of how life begins. You’d love to actually find evidence of that event in the geological record, but on Earth the early record was destroyed by volcanic and tectonic processes. You don’t find 4.3-billion-year-old rocks here. Yet literally half of Mars is covered with rocks that old. So if—big if—life ever arose on Mars, not only could we find out, yeah, there is life somewhere else in the solar system, but the record of how that miracle occurred would still be preserved in these ancient rocks. If you want to know how life first arose, Mars might be the place to get an answer.
Carl Sagan was a close colleague. What do you think he’d say about these missions?
S: I think he’d think this mission was a hoot. I think he’d want to be here with his sleeves rolled up, having fun going through the data like the rest of us.
How did you get interested in planetary science?
S: Back when I was an undergraduate student at Cornell, I went into geology because I liked to do science and I loved to climb mountains, and geology seemed like a good way to combine those two passions. After a few years, I came to realize that the geologists who have studied this planet had actually done a pretty good job of it, so to a certain extent studying the geology of Earth felt to me like filling in details. Then in my junior year I signed up for a course being taught by Joe Veverka, who is now chairman of the department. He was on the Viking Mars mission science team in 1977 and was teaching a course on the results. That course really changed my life. Because it was a graduate-level course, we were supposed to write some piece of original research. There was a room where they kept all the pictures from the Viking missions—this was before the Internet, CD-ROMS, and all that stuff—and a few weeks into the course I went to look at the pictures, figuring I’d flip through them for 15 or 20 minutes to try to figure out what I would write my term paper about. I was in that room for four hours. I walked out knowing exactly what I wanted to do with the rest of my life. Here was this whole world that no one knew anything about, and it wasn’t filling in details: It was a very big blank canvas. That was it.
Why do you personally study Mars?
S: Because among all the planets, it is the one world where we can imagine life as we know it taking hold. The other solar system body that has always intrigued me, for the very same reason, has been [Jupiter’s moon] Europa. Europa has enormous appeal to me, but addressing the water and life problems there would require submarines, versus rovers on Mars, which is something I can do now.
What is it like working on Mars time? Do you feel disconnected from the world?
S: Getting into Mars time is tough. The way it works is that the Martian day is 24 hours and 39 minutes long, and so if today’s science operation working group meeting starts at noon, then tomorrow’s will start at 12:39, the day after that, 1:18, and 2 1/2 weeks from now it will be in the middle of the night. So if you are on Earth time and you have to suddenly jump to Mars time, you can get a wicked case of jet lag, which can be mild or terrible depending on when you do the jump. What is really rough is changing rovers, because they are on opposite sides of the planet and so are 12 hours apart. It is like getting on a plane and flying to India.
That having been said, once you get yourself in the groove and sync yourself with Mars time, it is not that hard. You get to sleep an extra 39 minutes later every day. Maybe that’s hard if you’re a morning person, but getting a little extra sleep each day feels good to a night owl like me. When it becomes tough is when you are trying to do the Mars time thing and the real world intervenes. For example, right now it is almost midnight Pacific time, but it is 9:30 p.m. at Meridiani Planum. My shift normally ends a little after midnight Mars time, so I get off work about three hours from now. But unfortunately a very important meeting having to do with long-term planning, budgets—stuff that I need to worry about—has been called for 8 o’clock Pacific time tomorrow morning, right in the middle of my night.
What are you working on after this mission
S: Getting some rest and spending a lot of time with my family. I am a member of the imaging team for the Cassini mission [which will arrive at Saturn in July]. My goal for planetary missions from here on out is to find roles where I can have a lot more fun and a lot less responsibility. Actually, no, I can’t imagine having more fun, but a lot less responsibility.
What is the biggest challenge of your job?
S: I think the biggest challenge is trying to balance all the competing desires among the science teams. I’ve got 170 people on my team, split into two groups, one working on each rover. On any given sol [Martian day] you’ve got 50 people working on a given rover. Of course everyone has their own interests and their own ideas about what we should do next, so I have to find the best ideas and build a consensus around them. You never want to have the person leading the science team be a dictator. And you can’t just think tactically—think this sol, and the next sol, and the next, one at a time. It all has to be part of a sequence that makes sense strategically.
If we didn’t have such an enormously flexible and capable vehicle, this would be fairly easy. But these rovers are like Swiss army knives, with so many tools and so many capabilities, that finding the way to get the optimum usage, given all the constraints and all the desires and all the science you want to do, is a wonderful challenge to try to meet every day. It is like nothing I have ever experienced before. It is intricate, it is fascinating, and it is an incredible amount of fun.
Do you know the final date of the rover missions, when it all ends?
S: It ends when the last rover dies. We had an advertised design lifetime of 90 Martian days per rover, but I think they will last a lot longer than that. Twice that is possible. We will work ’em as hard as we can until they are both dead.
S: At some point, you just pack up and go home. But we are generating an enormously rich data set. I have no idea how many scientific papers, how many scientific careers, how many Ph.D.’s will come out of this mission, but there are going to be plenty. So, yeah, we’ll pack up and go home, and that will be both a wonderful and a very sad day, but milking the data for everything in it will take a long, long time after that.