For scientist Suzanne Smrekar, the upcoming Mars mission is like an anthropologist going on the ultimate dig.
Smrekar is a JPL project scientist for the Deep Space 2 microprobes. Once released from the Mars Polar Lander, two Deep Space 2 microprobes will hurtle down through martian sky, gathering atmospheric data before they crash into Mars at about 200 meters per second (400 miles per hour).
"You study other cultures in order to get some perspective on your own. You study other planets in order to get some perspective on the Earth. I like that aspect of planetary science. It gives you a new twist on things," Smrekar said.
Among the instruments, each microprobe will draw into itself a meager-sized soil sample, heat it, and then use a miniature laser to look for signs of vaporized water ice. No small order, even though onboard equipment is ultra-tiny, Smrekar said.
"I like puzzles. I like to solve problems," she said. "And I like to explore... whether it's on the anthropological level of studying different cultures, going hiking, or sending missions to Mars."
Space.com sat down with Smrekar as Mars Polar Lander and the piggyback Deep Space 2 microprobes hone in on their target.
Q: The Deep Space 2 project is comprised of a pair of basketball-sized microprobes loaded with new technology. How did the penetrator design evolve?
Smrekar: We actually went through at least 10 to 12 designs, including penetrators shaped like rockets. We tested most of the designs out over the Mojave, dropping them out of airplanes over the desert. A couple of times, skydivers helped us out too.
There were some big challenges, like handling gusts of wind that might put you at such an angle that the penetrator just flops over and doesn't penetrate. All the tests helped us settle on the squat design, something like a shuttlecock. With all the weight in the nose, it (corrects) itself and keeps going into the martian atmosphere straight.
Q: Since the Deep Space 2 is a technology demonstration mission, did science have to take a back seat?
Smrekar: It took some getting used to that I was project scientist for a technology mission. It's usually the science up front that drives everything. The first task was to figure out what these probes should be doing to enable the most science for the future. The science had to be useful for future missions.
Q: And the result?
Smrekar: The team tried to give us the most science they could, even though it was a technology mission. Science wasn't treated like a second-class citizen. Everything was driven primarily by schedule. More time, more money always helps. It's not like you design your instrument over there and you bolt it on at the last minute. Everything has to be done at the same time, tested and verified, before you integrate. There was one unfortunate casualty along the way.
Q: Which was what?
Smrekar: An atmospheric pressure sensor, to take measurements on the surface. There was nothing that could be done about it, really. The telecommunications system just ate up the real estate on the probes.
Q: How much nail-biting will you be going through once the probes have impacted the surface?
Smrekar: [Yes], in terms of data from the probes sent to the Mars Global Surveyor (MGS). It could be a long wait to get confirmation. First of all, the geometry between the MGS and the probes may not be favorable [during] that first pass. It might be the next pass or the third pass before we get data.
Q: The probes will be hitting the surface some distance away from the Mars Polar Lander. How distinct is the impact area for the probes relative to the lander?
Smrekar: I would be surprised if we will go into exactly the same type of terrain as the lander. That's good. If we all find water, then water is pervasive. If the lander detects water and we don't, that'll give us some idea of what the differences are from terrain to terrain. For the first time, we'll have three points on the surface of Mars from which to study the planet.
Q: Is it possible that the penetrator probes could shoot right by any trace of water on impact and come up dry?
Smrekar: We don't know. That's why we're going. You can have soil, an ice pocket, then soil again. What we hope is that, if there are significant layers, probably on the order of 10 centimeters or more, we will be able to see change with the impact accelerometer... hard and soft, hard and soft, etc.
Q: How do feel about the role of planetary science in better understanding our own planet?
Smrekar: We like to explore to better understand ourselves. By exploring other planets, we do understand more about the Earth, which is really the most thrilling aspect. For me, it is clearly true. What we learn on other planets can be applied back to Earth. [We discovered] the greenhouse effect on Venus, for example. Mars has changed dramatically. If we can understand what the major factors were that changed the climate for Mars, we can feed that back into our understanding of changes here on Earth.
Q: How do you answer those who want 'instant science' - quick answers to big questions?
Smrekar: It's not a simple process. Science works that way. You need a perspective over here to help to understand what's going on over there. To understand a planet as a whole there are many questions to ask that can't be answered at once. So you just have to be patient and work on... advocating the questions and seeking the answers that are important.
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