Planetary Radio: Space Exploration, Astronomy and Science - A Mars Rover Update From Steve Squyres

Episode Date: April 14, 2008

Steve Squyres gives us a status report on Spirit and Opportunity, and Bill Nye comments on the rings that appear to surround one of Saturn's small moons. Last week Emily Lakdawalla told us why objects in space are round, but this time her Q&A explains why they're not.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

A Mars rover update from Steve Squires, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. They keep going and going and going, more than four years now, and those Mars exploration rovers are still phoning home exciting and surprising data about the red planet.

We'll get a status report from MER principal investigator Steve Squires, and see if you can tell if he loves his work. Bill Nye the Science Guy sees a wheel within a wheel out at Saturn where tiny moon Rhea may have its own rings. Last week, Emily Lakdawalla explained why all the big objects in the universe are spheres. This time she'll tell us why they're not. And Bruce Betts is itching to share news about the night sky

and give away another Planetary Radio t-shirt. Did somebody say news? The next spacecraft that will reach Mars was just successfully nudged toward a tentative landing spot near the North Pole. The latest on the Phoenix lander is at planetary.org. Touchdown is May 25, and that's when the Planetary Society will be celebrating in Pasadena at Planet Fest 08. Want to see yourself and everyone you know rise above the moon's horizon? Check it out in Emily's blog at planetary.org. That's also where you can read about our proposal to fly Cassini between Saturn and its rings.

Here's Bill Nye. Hey, hey, Bill Nye, the planetary guy here, vice president of Planetary Society. This week I'd like to talk to you briefly about many people's favorite planet. And I'm talking about Saturn. And everybody loves Saturn because it's beautiful. Why? Because it's got the rings. Discovered but not fully understood by Galileo, understood very well by Cassini. We have a spacecraft named Cassini out there in the vicinity of Saturn right now.

What do we all love about Saturn? The rings. Well, you know how many moons Saturn has along with its rings? It's got 47 moons that we're sure of. It probably has three more. 50 moons at least. Well, get this. One of them may have its own rings.

See, Saturn to the Romans was a god. And of course, gods have minor gods. I mean, they're minor gods, but they're gods. They're just minor ones. Anyway, one of them was Rhea. So, this spacecraft has MIMI, the Magnetospheric Imaging Instrument. And it's watching the plasma, the charged particles, coming from the sun and getting influenced by Saturn's magnetic field. coming from the sun and getting influenced by Saturn's magnetic field.

Well, when you looked at the field as it went past Rhea, there were three spikes where the flow of these charged particles, electrons, just went away. And then three spikes on the other side that are almost perfectly symmetrical. It reminds me so much, my friends, of when the rings of Uranus were discovered. It was 1977 as disco was giving way to punk. Yes. And so you see these symmetrical spikes on each side of this object. And get this, they're not perfectly symmetrical. And the asymmetry in their symmetricism, if I may, is exactly as predicted by a mathematical model.

Check this out! A moon of a planet with rings has got its own rings! Planetary exploration is exciting, my friends. Check all these data out on planetary.org. I've got to fly. Bill Nye the Planetary Guy. Sure, we talk about the Mars Exploration Rovers all the time, but we haven't checked in with their science boss for a while.

Steve Squires is Principal Investigator for Spirit and Opportunity. The Cornell Professor of Astronomy loves his little rovers that have been crawling about the Red Planet for more than four years. They were only warrantied to last a few months. Spirit continues to save its strength in a Gusev Crater parking space waiting for the Martian winter to pass. As you'll hear from Steve, Opportunity is on a perilous adventure in Victoria Crater on the other side of the planet. Steve Squires is the author of the book Roving Mars,

companion to the excellent IMAX movie of the same name. I got him on the phone just a few days ago. Steve Squires, we get to you too late to wish happy birthday, fourth birthdays, at least Earth birthdays, to Spirit and Opportunity. But it sure is nice to get you back on the show. Glad to be here. You're still doing lots of science up there. Still very exciting things happening on the Red Planet. Yeah, yeah. Both vehicles are alive, well, very active doing

science. Things are exciting. In fact, things are extremely exciting with Opportunity right now. I'm not quite sure how this current activity is going to play out, to be honest with you. But we're keeping both vehicles and ourselves very busy. You know, I just read in a very long article, it's almost a book, by my colleague AJS Rail. It's posted at planetary.org. But she talked about your excitement over what Opportunity is doing in Victoria Crater. Yeah, it's been exciting, and it's going to get more so, I think. What we've been doing so far is working our way down the wall of the crater. We're down inside the crater now.

We've been working our way deeper and deeper into the crater and investigating the layering in the rocks, the stratigraphy as we go, and making discoveries as we've gone down there. We've gotten to the point now where we've gone as far as we think we can productively down the crater wall in terms of exposed bedrock because from there on down it appears to be mostly sand. So what we're trying to do now, and speaking right now today, I can't tell you whether we're going to succeed or not.

What we're trying to do is get the rover over to the base of a big 4, 5, 6-meter-tall vertical cliff, a place called Cape Verde. It's proving to be challenging. The terrain here is veryde. It's proving to be challenging. The terrain here is very steep. It's slippery. We're kind of right at the ragged edge of what the vehicle is capable of doing. We certainly do not want Victoria Equator to turn into a permanent home for opportunity because we have a lot more science that we want to do out on the plains after we're done with Victoria.

So we're proceeding very cautiously and hoping we get through this okay. The last few drives have been, we've seen a lot of wheel slippage, you know, the vehicle's not in any danger, but it's giving us clues that this terrain that we'd like to drive it over is going to be challenging. So we're, let's just say that the rover drivers are earning their salaries. Well, it certainly adds to the drama as well. Yeah, as if we needed more, right? That's right. But the science is tremendous.

I mean, here you are. Science has been good on both sides of the planet, actually. What we've been seeing with Opportunity is trends in the chemistry of the rocks as we go deeper. As we go deeper into the Victoria Crater, we're seeing more and more chloride salts. We're seeing less and less magnesium sulfate salt. This is, interestingly enough, identical to trends that we saw six kilometers to the north at Endurance Crater and that we attributed there to being the result of these rocks, after they were laid down, having been soaked in liquid water.

What that says is that this soaking in liquid water was not just a local phenomenon. It was regional in scale because we're seeing the exact same trends of two craters that are six kilometers apart from one another. Are we looking then at possibly a regional condition, or is this something you'd find all over? I think it's regional. I think what you had was a water table that was regional in extent. Now, how big, I don't know. All we've got is these two data points six kilometers apart. But, you know, Meridiani Planum, the place where the rovers are located, where the rover is located, is pretty homogeneous over a much larger area than that.

So I could see this being a fairly extensive body of subsurface water that would occasionally locally come to the surface, but mostly it was below the surface. There's some interesting photographic work being done, imaging work being done as well by both rovers, and one of them is a tribute to a science fiction or science artist. Chesley Bonestell, that's right. Chesley Bonestell was perhaps the most influential science fiction artist, or space artist, I guess, if you will, in history. He was active, I'm going to say, like 30s, 40s, 50s, that time frame, and really produced some of the classic pictures that we've all seen of Mars and moon bases and space stations and that sort of thing.

His images illustrated all sorts of places. If I showed you one, you'd say, oh yeah, I've seen that guy's work. What we've done, every time we take a big panorama, we give it a name, because that way we can tell our panoramas apart. We don't want to just call them panorama number six, number seven, number eight, and so forth. In this area of home plate in Gusev Crater where the Spirit Rover is, we had been naming rocks after science fiction characters, science fiction writers, especially writers who had had an interest in Mars and stories about Mars. So we needed a name for this panorama, and especially given the visual impact of Bonestell's work

and what we think is going to be the very dramatic nature of this panorama once it's all done, it seemed like a very fitting name for this one. So, yes, we are, I'd say, a quarter or a third of the way now through acquiring the Bonestell pan. The thing about this panorama, it takes much longer to acquire than most of our panoramas normally do because we are using every color filter that we have. We're essentially doing no data compression. It's going to be the highest quality image that we can possibly take. And, you know, we don't normally do that because it takes so long, but this is a situation where the Spirit Rover, in order to conserve power during the very cold and dark winter months,

is parked stationary for an extended period of time anyway. So we take advantage of the fact that we're not moving for a period of months, and we take the mother of all panoramas. And there's no question that you can do a lot of science without roving around the planet, as has been proved in the past. That actually kind of caught me by surprise when it first came up. You know, we designed these things to be rovers, not landers. But it turns out they're actually pretty good landers, for a while at least. Now, you know, I wouldn't want to keep one of these things parked for a year or two, because, you know, after a while the scenery doesn't change and you start running out of

things to do. But there are some very interesting things you can do. There's science that is enabled by being motionless. There are changes on the surface of Mars. Things change all the time. They change because of the wind moving things around, for example. The problem is if you're always moving, you can't detect that. You image something, but then by the time it's changed, you've moved someplace else or it's out of view.

Or you image something, and then by the time it's changed, you've just moved to a different vantage point. So the viewing geometry is different, and you can never tell, well, is it because I moved or is it because the scenery changed? So if you stay motionless, it's much better for studying these sorts of dynamic phenomena. There are also things that you can do with the rover's arm and the instruments on it that can take many weeks or even months to do, where you do multiple observations of a single target, moving the arm a little bit between each one. And I won't go into the details of the geochemistry, but you can actually build up chemical information that is very unique that way

that you can't get with a single measurement. So what we're doing is taking advantage of this forced immobility to do a whole class of science that we normally just don't get to do. That's Steve Squires, Principal Investigator for the Mars Exploration Rovers. More in a minute. This is Planetary Radio. I'm Sally Ride. After becoming the first American woman in space, I dedicated myself to supporting space exploration and the education and inspiration of our youth. That's why I formed Sally Ride Science,

and that's why I support the Planetary Society. The Society works with space agencies around the world and gets people directly involved with real space missions. It takes a lot to create exciting projects like the first solar sail, informative publications like an award-winning magazine, and many other outreach efforts like this radio show. Help make space exploration and inspiration happen. Here's how you can join us. You can learn more about the Planetary Society at our website, planetary.org slash radio,

or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. Steve Squires is giving us an update on Spirit and Opportunity, the Mars exploration rovers that have fascinated and inspired a global audience. Steve is the MER principal investigator, or more accurately, the principal investigator for the Athena Science Payload on both rovers, which is, after all, why they're on the Red Planet. The Cornell Professor

of Astronomy has devoted a substantial portion of his life to this mission, and with luck, he's not even close to the end. I talked with him about what's in store over the next few months, but first we talked about how very undead Mars is. Mars is a very dynamic place. Yeah, it has actually surprised me by how dynamic it turned out to be. I was expecting things to be fairly static, and particularly at the Gusev site where Spirit is, largely because of the dust devils. You know, it's Dust Devil Alley, and these things come roaring through there and move stuff around and do so in pretty dramatic fashion.

And blow the dust off solar panels, too. Yeah, I'm waiting for that one. We could use one of those. Oh, man, that thing is filthy. I mean, you know, you take pictures of it. We can take panoramas that include the rover, right? We can take a self-portrait. And you take a picture of spirit these days, and it's against, of course, a background that is Mars. And you look at the picture, and for a second, you say, where's the rover? Because it's Mars-colored. It's camouflaged. I mean, you'll see there's an antenna there and a calibration target over here, but the solar arrays are just completely Mars-covered. It's amazing to me the thing's still alive, but in fact it's doing astonishingly well. But, yeah, we could use a wind gust right now. What are we looking forward to for both rovers?

Okay, let's do Opportunity first. Opportunity, we're going to finish up with Cape Verde, whatever that means. And maybe that means we get to Cape Verde and we do our thing there. And maybe it means we bail out. I can't tell you for sure we're going to make it to Cape Verde because this terrain is really pretty challenging. So we're going to give that our best shot. If we make it, great. If we don't, then that's it. And then at that point, we leave Victoria Crater and we leave it behind for good. After that, we got two things. One is something we're calling the cobble campaign. There are a bunch of small rocks, you know, size of your fist, size of a potato, something like that, that we've seen scattered about on

the plains. We've hardly looked at them. I mean, we've looked at maybe a half a dozen or something in detail. And the fascinating thing is the half dozen that we've looked at, they're all different from one another. They're very diverse. And that's really in contrast to what we see in the bedrock at Meridiani. The bedrock is sort of the same everywhere, but these lumps of rock out of the plains, some of them are meteorites, and we have found several meteorites that way. And then some of them are ejecta from craters that are pretty far away. And what that means is that they sample depths within the crust that are much deeper than we can ever get to with the rover itself. So Mars has delivered these rocks from the subsurface up to the surface where we can find them and look at them. We were in such a hurry to get to Victoria

Crater that we just blew by these things. You know, we'd take a quick look at them with Pan Cam, but that was it on the way south. And now that we're done with Victoria, we want to go out and look at these in detail because we think that they might tell a very interesting story about what lies underneath the stuff that we've been driving around on and sampling. So that's the first thing. The second thing we're going to do is we're going to go off in search of additional rock outcrops, in particular looking for more evidence of places where water has come to the surface. The best examples that we've found of that have been in craters that have been very deeply eroded.

found of that have been in craters that have been very deeply eroded. There was one called Erebus Crater that had some spectacular evidence for water ripples and that sort of thing. And so we're going to search for more of that. For Spirit, Spirit's the one I'm frankly really excited about. Once winter is over, we're kind of getting into the worst part of winter just now. I think the very worst is going to come sometime in May, June. I think the very worst is going to come sometime in May, June. But by fall on Earth, by September-ish, September, October, it will be spring on Mars.

Sun will come back, power will start to pick up, and we'll be ready to move the vehicle again. To the south of us, and it's not that far, it's a couple hundred meters. To the south of us are two features named Von Braun and Goddard. Von Braun is a hill, Kama Mesa with some material on top of it we think might be made of the same stuff as home plate is. We want to check that out. And then Goddard is this fascinating thing. It looks like it might actually be the site of a volcanic explosion. It's a pit, and it doesn't look like an impact crater. It looks like something different. is something like something we've never seen before what we're finding at at the goose F site at the spirit site is lots and lots of

evidence for hydrothermal activity for interaction of water with lava for interaction of water with magma for hot water bubbling out of the ground we found these fabulous deposits of nearly pure opal and silica, the kind of stuff that you would find, for example, at a hot spring sort of environment. And so we're seeing all this evidence that there was hot water beneath the ground interacting with the rocks at the Gusev site. And now we've got this thing, you know, 250 meters, 200 meters to the south, that looks like it might actually be the place where a volcanic explosion took place. And so we're really, really interested in getting to that and seeing what further evidence, in particular of hydrothermal activity, we might be able to find there.

So that'll come, you know, once springtime comes. You are so far out of warranty on these machines that it puts every automobile on Earth to shame. At some point, it's going to come to an end yes i don't want to turn this into a eulogy for machines that are still doing great work but have you started to think about the legacy of these rovers and what they mean for the bigger picture with mars exploration many more we hope many more missions to come you know it's hard for me to do that it's hard for me to do that. It's hard for me to do that for a couple of reasons. One is, as you say, they're still active. And, you know, we're doing this interview on the phone right now.

And as soon as we're done, I'm going to dial back into flight operations, planning for the Opportunity rover for Sol 1496, which is what we're planning today. Okay. So I am deeply enmeshed in, in rover flight operations. And, and it's, it's hard to think in those terms right now, to be honest. The other thing is that, you know, I'm so close to this. I'm probably the last guy who ought to be talking about what the legacy, legacy of these things is anyway. You know, I, I've been, I've been living and breathing this stuff for 20 years now, and it's really hard for me to kind of step back and take in the big

picture. So I'll let you figure out what the legacy is. Steve, we're out of time. You know, if you could turn to anybody to take one of the most exciting space exploration missions in the history of our species and make it even more exciting, you're the guy to talk to. Well, you know, if you can't have fun driving rovers around on the surface of another planet, just give it up. What's the name of the book?

Roving Mars? Name of the book is Roving Mars, that's right. Okay. Thanks so much, Steve, for joining us once again, and I hope we can have you back on Planetary Radio soon. I'd love to do it. Steve Squires of Cornell University is the principal investigator for the Mars Exploration Rovers,

both of them still doing the most amazing work up there on Mars, four Earth years and two of the Martian variety. We're going to get to Bruce Betts for this week's edition of What's Up and find out if Mars is in the sky. I think not at the moment, but that'll be after we hear from Emily. Hi, I'm Emily Lakdawalla with questions and answers. Last week, I explained why planets are round. This week, I'll explain why they aren't perfect spheres.

The number one contributor to a non-spherical shape for planets is rotation. Any rotating body gets flatter pole to pole and fatter around the equator, a shape called an oblate spheroid. Earth has a relatively small equatorial bulge of about 40 kilometers. By contrast, fast-spinning Saturn is more than 10% fatter across the equator than it is from pole to pole. The shape gets more complicated for bodies that are locked into synchronous rotation. Nearly every large moon in the solar system constantly shows the same face to its planet. These moons have both a rotational bulge and a tidal bulge.

They have to be described as triaxial ellipsoids with three different length diameters. They're fattest in the direction measured through the tidal bulge, narrowest from pole to pole, and an intermediate width measured in the direction parallel to their orbits. Sometimes geology happens that makes a triaxial world even lumpier.

For instance, at some point in the distant past, some volcanoes got started on Mars that may never have stopped erupting. They have built an enormous complex of mountains called the Tharsis Bulge on one side of Mars. Many geologists think that Tharsis may have started out in some other place on Mars. But when all that mass started piling up on one spot, Mars became rotationally unstable until, like a top spinning down, the mass of Tharsis actually reoriented the whole planet's crust until the Tharsis Bulge got to its current position,

which is centered on Mars' equator. A similar process involving a lack rather than an excess of mass may be responsible for the south polar location of the geysers of Enceladus. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Okay, so I forgot that Bruce was headed up to Sacramento this week, and that's why he is on the phone. And we're just going to have to hold off on that contest that we talked about, our random space fact contest, which we will explain when the time comes. But let's welcome the Director of Projects for the Planetary Society. Hey, Bruce. Hey there. Anticipation will just make the contest all the more satisfying. Oh, I'm sure people are chomping at the bit. You

know, I've decided it would be more authentic to record if I did it outside under the night sky, so that's what I'm doing. Good excuse. What is up? What do you see there? Well, right now I see the Big Dipper Ursa Major, and if you follow that handle and you arc the handle, you come to the bright star Arcturus. Cool, huh? Yeah.

But if I look the other way, which I won't because of the possible wind noise, I'd see a couple planets right now because we're recording in the evening. We've got Mars in the early evening, high in the west, looking orange and bright, but not incredibly bright. It's above Orion, if you can see Orion there. And we've got Saturn looking kind of yellowish and farther over towards the east, but also very high up, a very nice telescopic object. Check out the rings. You've got a small telescope. And in that pre-dawn sky that I'm not looking at, you can see incredibly bright Jupiter looking like a really bright star-like object over there, low in the east. And that's the rundown. And check out that

Ursa Major Big Dipper thing. I like that. Oh, and there's that, we talked about them just a little while ago, that pole star. I see that. The current. I hear that's north. Yeah, the current pole star. Would you like more? Are you just looking for information?

Anything you'd like to share. How's the traffic? It's not as bad as Southern California, but a lot worse than when I grew up here. Anything else you want to know? I thought maybe you'd have some other things you'd want to tell us. All right, well, let me tell you something else about space. In fact, let me tell you about the Random Space Bags. Wow, snuck up on me.

Yeah, well, I'm feeling kind of sneaky tonight. And I'm also getting some interesting looks from people in the parking lot. Tell them to tune in. I hope you're wearing your T-shirt. I never take it off. The Cassini spacecraft currently in orbit around Saturn. It's about the size of a small bus, the last of the big old hanging robotic spacecraft. It's got a radio dish that's four meters across.

It's got a bunch of stuff on it. It's got a radio dish that's four meters across. It's got a bunch of stuff on it. It's really cool. It's so easy to forget how hulking big that thing is. It is hulking big, especially compared to most of the other planetary spacecraft. So there's your random space fact. Let's go on to the trivia contest, shall we? We asked you, what was the spacecraft that first observed this amazing gamma ray burst that occurred on, I believe, was that roughly March 18th? It was the brightest gamma ray burst ever seen, and had theoretically this visible component, which could be seen with the naked eye for a short period of time, like maybe an hour, and if you looked at just that time, you were looking a billion years away with the naked eye.

But what spacecraft saw in gamma rays first, and how did we do, Matt? You know, I think this threw some people because it happened so very recently. I had it down for March 19, by coincidence, the day Arthur C. Clarke died. A little cosmic fireworks show to mark that event. Wow, also Swallow's Day. That one got to Toronto, but go ahead. But most people did come up with the right answer. Ron Miller was one of them, Ron Miller of Fairhaven, Michigan.

And if that name sounds familiar, it's because he won just two months ago, slightly less than two months ago. Ron said it was the SWIFT satellite. SWIFT, which is a very apt name. Indeed. Indeed. It's, I think, an acronym. And it's SWIFT in its ability to catch these gamma ray bursts and then notify the astronomical community all over the world. So they can get lots of observations very quickly since these things dim very rapidly. So congratulations. Yeah, Ron, we're going to send a t-shirt off to you. And what do you got for next week? Well, I'm feeling generous. So I ask you, what is the most rodent-like instrument on the IDD on both spirit and opportunity?

Ah, come on. Do you think? All right. No, it's all right. No, no, no, no, no. Stick with it. Go with it. I want to see what kind of response we get to this. All right.

Rodent-like instrument on Spirit and Opportunity on the IDD. Okay. Go to planetary.org slash radio. Find out how to enter and compete for a Planetary Radio t-shirt. If you have the winning entry and you are randomly selected to be our winner. And if you get the answer wrong, then you can't listen to the show for two weeks. No, what did I say? I take it back.

You've got to get that answer to us, though, by Monday at 2 p.m. Monday, the 21st of April, and then you will definitely be eligible. That's it. All right, everybody, go out there, look up in the night sky, and look at the night sky. Think about the night sky. There it is.

Thank you, and good night. He's Bruce Betts, the Director of Projects for the Planetary Society. He's with us every week here for What's Up, and now and then, right out there under that sky. Is our galaxy littered with rocky, Earth-like planets? That's our topic next time, when we'll talk with astronomer Michael Meyer. His international team of scientists has

evidence that at least 20, and possibly as many as 60% of stars have at least one of those rocky planets, and that's a lot of room in the Milky Way for other Earths. Planetary Radio is produced by the Planetary Society in Pasadena, California. Hey, if you catch us via podcast, why not write an online review? Thanks, and have a great week. Thank you.