IRA FLATOW, host:
You're listening to TALK OF THE NATION: SCIENCE FRIDAY. I'm Ira Flatow.
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Up next, something that we think is really worth watching, and those are the Mars rovers. Like those energizer bunnies, you know, they keep going and going and going. And they're being sent to the red planet - they were sent to the red planet in January of 2004 on a 90-day mission - that's a couple years ago, on a 90-day mission to explore the planet in search for signs of water.
And today, you know, nearly three years later, they're still going. Showing some signs of wear, but you would be showing some signs of wear if you were rolling around a Martian surface. They're still collecting data, though, from Mars.
And for the rest of the hour we're going to check in on the rovers. One rover in particular, Opportunity, is about to arrive at Victoria Crater after a very long and treacherous journey.
And if you'd like to join us, our number is 1-800-989-8255, 1-800-989-TALK. And if you surf over to our Web site right now you can see that treacherous journey that the Mars rover is undertaking.
And speaking with me from the safety of his office, I hope, Steve Squyres is principal investigator for NASA's Mars Exploration Rover mission and professor of astronomy at Cornell in Ithaca. Welcome back to the program.
Professor STEVEN SQUYRES (Professor of Astronomy, Cornell University): Hey, Ira. How are you doing?
FLATOW: How are you? You know, I keep finding myself singing the Gilligan's Island theme song about a three-hour tour that went on much longer.
(Soundbite of laughter)
Prof. SQUYRES: Yeah, it's been kind of like that.
FLATOW: You feel that way, too, huh?
Prof. SQUYRES: Yeah. You know, none of us expected it to go this long. We're exhausted, but we're really having fun.
FLATOW: So they're going to just go until they quit on their own. You just don't know when they're quit, but you're hoping they stay working or at least one of them going to the crater just for a few more days.
Prof. SQUYRES: Yeah. We're only, you know, about 100 yards away from this crater now. It's a place that we've been trying to get to for almost two years. So we're very excited and sure hoping the rover holds together for a little while longer.
FLATOW: And when - if and when it gets there, what do you expect to see? What's the point of going there?
Prof. SQUYRES: Well, the thing that makes this crater exciting is that it provides a window into the subsurface of Mars that we wouldn't otherwise have. The rocks at this place are sedimentary rocks. And they're flat lying; they're like a stack of pancakes. And we've been driving over the top of this stack for miles. And the problem is you can't find what's underneath. What we really want to do is we want to see the layers.
Now, you know, we didn't bring a drill rig with us. And we didn't bring a big backhoe. But we've got these craters on Mars, and this is the deepest crater we're ever going to find with this rover. It's nearly 200 feet deep, and it's going to provide access to the subsurface that we haven't had before. And it'll let us see these deeper layers.
FLATOW: So you can actually send it into the crater?
Prof. SQUYRES: We think we might be able to do that. We will not know for sure whether it's safe to send the rover into the crater until we've actually seen the thing. We haven't seen it close up yet.
But even if all we can do is look at it from the rim, we're going to learn a lot. My hope - and my expectation, we'll see - but my hope is certainly that we'll be able to go in.
FLATOW: But why not go in? You're on overtime now, aren't you?
Prof. SQUYRES: Yeah. Sure. Absolutely.
FLATOW: This is just extra time.
Prof. SQUYRES: You know, these - the rovers are precious. The rovers are literally priceless at this point. And with a priceless asset you don't take unnecessary risks.
But this is the most precious science target that we have for miles in any direction. So we're going to be pretty aggressive about going after it.
FLATOW: Mm-hmm. 1-800-989-8255. Can you describe just how much wear and tear these rovers have had?
Prof. SQUYRES: Yeah. They're, you know, they're getting a little beat up. They're certainly dirty, which is a problem. You know, Mars is a dusty place, and we've accumulated a fair amount of dust on the solar panels. And what that does is it means that there's less power, less solar power, for the vehicles to use.
The other problem is that we've got a few little mechanical parts that are starting to wear out. For example, on Opportunity the right front wheel we can't steer it right and left anymore. Now it turns out we can drive just fine not being able to steer that wheel. We've learned how to do that.
On the Spirit rover one of the wheels won't turn at all, and so when we drive we have to drag that wheel along. But we've got five good wheels, and the rover still moves. So we're kind of limping a little bit, but we're doing okay.
FLATOW: How have the solar panels lasted so long? There was one point that we thought they would get dirty, covered with soot, with dust.
Dr. SQUYRES: We've been lucky. There's a lot of dust in the Martian atmosphere, and it's coated our solar rays. But on several occasions on both rovers we have had lucky gusts of wind that have cleaned the solar panels off, like going to a car wash - just lucky.
FLATOW: Wow. So we're talking all luck here. You can't, I mean…
Dr. SQUYRES: Well, it's…
FLATOW: You can't really be talking all luck.
Dr. SQUYRES: We got the rovers cleaned off. I think you can also attribute some of longevity to the fact that the engineers at the Jet Propulsion Laboratory who built these things built some really good hardware.
FLATOW: Let's see if we can take some phone calls before we have to say goodbye. Craig(ph) in Montrose, Colorado. Hi, Craig. Craig, go ahead. Are you there?
CRAIG (Caller): I guess you sort of glanced over there, but what parts do they expect to fail that would cause them to abandon the opportunity, and also what kind of data they might be collecting that will be useful for the proposed mission to Mars - the manned mission to Mars?
Dr. SQUYRES: Sure.
FLATOW: Is there any instant failure part that knocks one of them out now?
Dr. SQUYRES: We have a lot of electronic parts in these rovers that if they failed, that would be the end of the mission. We don't have a lot of redundancy in these vehicles. Now we have kind of the ultimate in redundancy in that we have two rovers, but there are many electronic components that if they failed, it would end the mission. You know, another possibility is just after a while, so many parts will wear out that we won't be able to move the rovers anymore, and you know, if that happens, that's probably at some point going to be a reason to end the mission as well. But right now, everything's holding together.
FLATOW: Are there cracked parts that if they crack a little more you're done?
Dr. SQUYRES: Actually there is. There is a crack in some wires on one of the motors that moves the arm on Opportunity. And while we can use it in its current state, if it develops more cracks, we may no longer be able to use the arm. Now we'd still be able to drive, still be able to take pictures, but the arm wouldn't be useful anymore.
FLATOW: Even just sitting there, couldn't it still be working from the solar panels if it never goes any other place?
Dr. SQUYRES: Yeah, and you know, once you can't drive it anymore, you've still got a lander mission, right? You can still take pictures, you can still collect data. The point is that after you've ceased to move - I mean, these vehicles were designed to go places - and once they can't go places anymore, even though you can do lots of science, after a while you're going to reach a point of diminishing returns.
FLATOW: So how close are we now to reaching that crater, you said 100 yards?
Dr. SQUYRES: About 100 yards away, yeah. I don't know when we're going to get there. It's not going to be any earlier than late next week. If you know…
FLATOW: Describe for us why it takes a week…
Dr. SQUYRES: …what Mars throws at us between now and then.
FLATOW: Yeah. Describe for us why it takes a week to go 100 yards.
Dr. SQUYRES: Well, it turns out that we have a lot of other things that we've got to do in the next week besides that. You know when you have an operating system or some software on your laptop and then you do a software upgrade?
Dr. SQUYRES: We're about to do a software upgrade on the rovers. We've spent the last year or more writing some very capable new software that will teach the rover a whole bunch of new tricks, make it smarter. We've got that software on board now, and we're going to start using that software early next week, and that process is going to take a little bit of time, and so unfortunately, that takes time out of our driving.
Dr. SQUYRES: Now once we've done it, we're going to have an even smarter rover, but it is going to take a few days out of our activities.
FLATOW: You've got my attention now. What kinds of new tricks could you teach it to do?
Dr. SQUYRES: Oh, let's see. One of the new tricks is that it'll be able to find dust devils on its own.
(Soundbite of laughter)
Dr. SQUYRES: We've taken pictures of dust devils before where we were kind of lucky and caught them in the act, but now the rover will be kind of able to look for those things and find them. That'll be cool.
Dr. SQUYRES: Another thing is a capability to - let's say from off in the distance, you know 50 - 10 feet away, say - we see a rock that we're interested in. We'll be able to drive to that rock and then reach out and touch it with the arm all in one day. It used to be that that was a two-day operation. You'd drive to it, you'd make sure the rock is there, and then you touch it with the arm. It's something we call go-and-touch, and it's something we've wanted for a long time, and that's in the new software, as well.
FLATOW: So you've given it more robotic function, in other words autonomous -acting on its own?
Dr. SQUYRES: Yeah. It's getting smarter. They're getting older and creakier, but they're also getting smarter.
FLATOW: Well, I think that's all of us, isn't it, Steve?
Dr. SQUYRES: Yeah, yeah.
FLATOW: Just like the rest of us, hopefully.
(Soundbite of laughter)
FLATOW: And so then you're not planning to be shutting it down, you're really planning to keep it going.
Dr. SQUYRES: Oh yeah, sure. I mean look, we spent years trying to build these things and get them up there. They cost $900 million to get to Mars and operate. We are going to squeeze every last drop of science out of these things before they die.
FLATOW: And where is Spirit? What is Spirit up to these days?
Dr. SQUYRES: Spirit's kind of resting for the winter. Spirit - it's wintertime on Mars right now, and Spirit unfortunately is at a higher latitude, it's farther from the equator than Opportunity. And Spirit's right in the middle of a very, very harsh winter right now with very little solar power. So what we've done is we've sort of parked Spirit on a steep slope that faces to the north, tilting the solar panels towards the sun, and we're just sitting there soaking up sunlight and doing science at that one location and waiting for spring to come. And once spring comes around in another few months, then we'll be able to start driving that rover again.
FLATOW: And where would you send Spirit?
Dr. SQUYRES: You know, we're thinking about that. There was a very interesting place called - a feature called Home Plate - that we investigated right before winter came on. And we knew winter was coming, and so we had to kind of rush through Home Plate, and we didn't do it as thoroughly as we all would have liked to. And so I think our first task after spring comes may be to go back to Home Plate and finish up some unfinished business there.
FLATOW: 1-800-989-8255 is our number. We're talking with Steve Squyres, who is the principal investigator for the Rover Mission. Last week you and your colleagues had a paper out in Science summarizing the Opportunity's accomplishments so far.
Dr. SQUYRES: Yeah.
FLATOW: Give us a rundown on what it has done, what it has found, in about the minute that we have left.
Dr. SQUYRES: What that paper did was sort of publish together in one place a whole bunch of findings that we have put together over the last couple of years. I don't have time to go through all of them.
FLATOW: No, go ahead. I'm going to - I misread the clock, so you have a few more minutes. Go ahead.
Dr. SQUYRES: Okay. One of the interesting things that we've seen along the way with Opportunity is we've seen these networks of polygonal cracks. They sort of look like mud cracks in the rocks. And in fact when we first saw them, we thought maybe they were mud cracks, which would've been pretty neat. Now these are rocks that formed, some of them in wind, some of them in water, long ago. When we saw these cracks, we thought they might be mud cracks, but then we started to see them in places like on the sides of boulders and kind of weird places where you wouldn't expect mud cracks. It turns out these rocks are made largely of salt.
They're made of sulfate salts, and sulfate salts can actually contain within their crystal structure a lot of water. Now what happens if you have a crystal structure of salts that has some water in it and then the climate dries out? The climate dries out, you're going to lose some of that water. It's going to evaporate from the rock and go to the atmosphere, and it turns out what'll happen is that the material will shrink. And as it shrinks, you can get these fractures develop in it. So we think that those cracks are actually from salts that have lost water. So that's one of the findings. A bunch of others, as well.
FLATOW: Talking with Steve Squyres this hour on TALK OF THE NATION Science Friday from NPR News. There was a report out a few days ago, a week or so ago, about the fact that there might be hydrogen peroxide in the soil. Wasn't it one of the orbiters overhead discovering that? Does that - and that would signal doom for any microbes that might be living there.
Dr. SQUYRES: Well, actually there's been a suspicion of peroxides in the Martian atmosphere and upper soil ever since Viking.
Dr. SQUYRES: There were some observations that Viking made that were kind of best explained if that were the case. What that does is it makes it very difficult for organic molecules to exist right at the surface, in contact with the atmosphere, because they'll get oxidized by that peroxide. But if the organic molecules have someplace to hide - deeper down below the surface, deeper in the soil or inside a rock, something like that - they might be able to persist for a very long period of time.
FLATOW: So it might just be a thin layer on top.
Dr. SQUYRES: Yeah, yeah.
FLATOW: Are future missions going to dig down deeper?
Dr. SQUYRES: Yes. Yeah, there's a very exciting mission called Phoenix that's in the works right now. It's going to launch next year, and it's going to land near one of the poles of Mars. And it's got a long arm, much longer than the arm on our rover, that's got kind of mini-backhoe on the end of it. And it can scoop down, you know, a foot or two into the soil where they may be ice and there may be who knows, maybe even organic molecules, and sample that material. So yeah, there are missions on the drawing board to do exactly that kind of work.
FLATOW: Are your missions to mars feeling any pressure from the president wanting to go back to the moon? Taking any money or any incentive or budget?
Dr. SQUYRES: You know, it hasn't really affected us in any direct way. Clearly this strong interest in Martian exploration just provides further impetus for this program. We've got two very healthy, very productive vehicles on Mars right now, and we see our contribution to that program as being try to squeeze as much as we can out of those vehicles.
FLATOW: And what have you learned about designing the next set of rovers?
Dr. SQUYRES: Oh boy, an awful lot, and fortunately the same people at JPL, at the Jet Propulsion Laboratory, who are designing the next generation of rovers are largely people who worked on Spirit and Opportunity. We've learned a tremendous amount. We've learned how to design a power system for the vehicle that will last for a long time. We've learned what kinds of motors to use, what kinds of hardware can survive the harsh conditions on the Martian surface for very long periods of time. I think one of the most important things is we've learned how to operate vehicles for months and months and months at a time. The next rover that goes up is going to have a power system that will enable it to last perhaps for years, and we have with our rovers learned a lot about how to do long-term operations of robots on Mars.
FLATOW: And I guess you can design them with the thought in mind that they can last much longer than their design limits.
Dr. SQUYRES: Yeah. The next rover is being specifically designed to last for a long time. Ours were designed only to last for 90 days.
FLATOW: And so you're waiting for next week to see what happens when you get to the crater?
Dr. SQUYRES: We're real excited. I don't know if it's going to be next week or maybe the week after that, but as soon as we can we're going to get that crater. And it's going to be a spectacular view. I mean, this thing is almost a half a mile in diameter. Like I said, it's about 200 feet deep. This is going to be the biggest, most impressive thing that we've seen with either one of these vehicles.
FLATOW: And if I were a gambling man in Vegas, I'd bet you're going in there.
Dr. SQUYRES: That's probably a good bet.
(Soundbite of laughter)
FLATOW: All right, Steve. Thanks as always for your candid comments and taking time to be with us today, and good luck when you get to the crater.
Dr. SQUYRES: Thanks, Ira, good talking to you.
FLATOW: Steve Squyres, principal investigator for NASA's Mars Exploration Rover Mission and professor of astronomy at the very famous Cornell University in Ithaca, New York.
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