The road to Mars has been a rocky one for Richard Zurek, the man who leads the troops in charge of making Mars Polar Lander figure out the red planet's water history and find answers to dozens of other science questions.
Zurek was part of the science team at Jet Propulsion Laboratory for the Mars Observer, a mission that failed in August 1993 just prior to arrival at the red planet.
More recently, Zurek suffered a similar loss as project scientist for the ill-fated Mars Climate Orbiter.
"It is kind of amazing ... those two strokes of fate. It's both ironic and, ultimately, quite a blow too," he says.
"There's not been enough time to go through a grieving process," Zurek says. "Right now, everyone is focused on the lander and getting that to work."
Needless to say, Zurek is primed and ready for Mars Polar Lander's southern hemisphere touchdown. Looking into his eyes, you can detect in the scientist an almost Land of Oz-like feeling of not being in Kansas anymore.
"We expect to see a very different landscape with this craft," Zurek says. Clearly, the landing spot won't look like Kansas, nor Arizona without the cactus. "It will be more like Alaska or Antarctica," he said.
Space.com made its own soft landing in Zurek's office recently, sitting down with a scientist that has his fingers crossed and high hopes that his third time at Mars is the charm.
Q: How will Mars Polar Lander add to the body of knowledge about Mars?
Zurek: The area of Mars is the same size of the land area of the Earth. When you think about trying to characterize the land area of the Earth by two Viking landers and the Mars Pathfinder -- well, you can't do that. You need something to connect that. The Mars orbiters do give us that global view and global context.
In landing at the southern hemisphere of Mars, we're looking for evidence of ancient climate change. But Mars Polar Lander is also looking at more recent climate change, which is represented by the layered terrain.
Q: Layering would indicate what?
Zurek: When you see layers, it says something repeats. Something changes between when that layer was formed and when the next layer is formed. We are going to try and look at that with the Mars Polar Lander.
Q: That's one of the tasks for the robot arm, correct?
Zurek: Yes. While we can only dig down just about one-half meter (1.6 feet) in the soil, it's quite possible that the annual layer, the layer that's put down each year on Mars, is very thin. Maybe just a fraction of an inch. So even in a meter of material, we might be looking at 100,000 years of geologic time.
Q: As always, there is worry about the landing site. Just how formidable is that area?
Zurek: The images of the prime site from Mars Global Surveyor have been very helpful. But one problem that we've had in the interpretation of these images is that we don't really have a good terrestrial analog.
There are only a few areas on Earth that are just exposed frozen ground at the kinds of temperatures that we're encountering in the Mars polar regions. And even there, the process of water as a liquid sort of dominates what the landscape looks like. The permafrost regions on Earth are dominated by short-lived freeze-thaw cycles, when water becomes liquid and moves through the surface.
Q: And on Mars?
Zurek: We don't think that happens for Mars. At the present time, water acts just as carbon dioxide does on the Earth. It goes from a solid to a gas without an intervening liquid phase. It doesn't melt, it just boils away into the atmosphere.
So the polar terrain on Mars is new stuff. We're still learning how to read the tea leaves ... how to read the book.
Q: If at the last minute you get nervous about the landing site, can you move the lander to another location?
Zurek: We're pretty much committed to the prime site. We can still move the target point just a little bit. If we see something dangerous right there in the center of our target ellipse, we could still try to move away from it. We can move as much as 31 miles (50 kilometers). But we can't move very much in longitude. We're aiming for a pretty small keyhole at the top of the martian atmosphere.
Q: What would you consider a 'eureka' moment for the Mars Polar Lander?
Zurek: You mean, other than the dinosaur bones sticking up out of the ground? Just kidding. What I'm looking forward to is the exploration of this new place ... to look for layering in that top most part of the layered terrain. Is it there? Are there fine scale layers that are, in a sense, the tree rings of the past climate record?
The other place where I would expect some surprises to come is in the soil samples themselves.
Q: Mars Polar Lander is the one and only time this type of region will be explored, right?
Zurek: Yes, but I think we're going to go back there. Maybe not soon, but I truly suspect that we will go back to the polar regions. They may be the special niches where you go look for the fossils, ultimately, or whether or not life ever developed. They clearly hold the keys to what the climate was like in past and how it might change in the future.
Q: Do you ever worry about beating the mystique out of Mars? Could familiarity breed contempt?
Zurek: Mars has continued to surprise us. Previous spacecraft sent there, like the early flybys and the Mariner 9 orbiter ... they've all provided surprises of one form or another. Now with Mars Global Surveyor (MGS), it's having a similar kind of impact.
MGS data implies that Mars wasn't just a dead planet that lost its water very early in its ancient past and hasn't changed hardly at all since. There's a lot of argument about this. But at least there's some suggestion that Mars has more surprises than we know.
Whenever you poke around in unexplored territory, that is what you find. You find surprises.
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