Planetary Radio: Space Exploration, Astronomy and Science - Mars Rover Project Manager John Callas

Episode Date: February 1, 2010

John Callas tells us why an end to Spirit's roving does not mean the end of her work on the red planet. Emily Lakdawalla looks to the other side of Mars where Opportunity is rolling up to a baby crater, and Bill Nye is head over heels for the highest ever skydive.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Mars Rover Spirit, a rover, no more. 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 of the Planetary Society. Mars Exploration Rover Project Manager John Callis returns to tell us about the permanent home Spirit has found on Mars, along with the challenges and opportunities facing the little ex-rover. And speaking of opportunity, Emily will tell us how we know

the small crater Spirit's sister is approaching is far younger than any examined before. Bill Nye and Bruce Betts, too, in a jam-packed episode. Emily, we're just a couple of minutes away from talking to John Callis, the project manager for the rovers. And one of the things people are going to hear him mention is this little crater, cute little crater that Opportunity is approaching. In fact, in your January 29 blog entry, you show that Opportunity is just about on top of it. Yeah, it's quite a cute little crater, and it's very, very blocky. Clearly, it's a very fresh crater.

It happened not very long ago. And as a matter of fact, in a JPL update, they said it was about 1,000 years old. And that made several people wonder, how do we know that it's 1 a thousand years old? After all, we weren't there when it happened. I didn't know the answer to that. So I sent an email off to a couple of the geologists on the mission. And Matt Golombek answered my question. And he said, that's actually work that I did. It goes back to trying to figure out when the dunes at Meridiani last moved. And they counted craters all over those dunes in images from the HiRISE and CTX cameras on Mars Reconnaissance Orbiter. And they figured out

by the number of craters that have appeared on those dunes since they last moved, that the dunes last moved about 100,000 years ago, give or take. And we know that Concepcion crater is fresher than the oldest craters that have appeared since those dunes formed because opportunity visited some some older ones actually there's a whole cluster of craters called a resolution cluster that are definitely older than concepcion concepcion has dark rays the resolution cluster of craters didn't but then there are other craters in the meridiani area that are even fresher than concepcion they have both dark and light rays. The light rays at Concepcion have disappeared with time. And so this is an opportunity for them to study

a crater of intermediate age where the rays have not yet, the light rays have disappeared, but the dark rays have not yet disappeared. And they'll get a chance to actually try to figure out what makes up those dark rays that you can see from orbit. So I have a feeling they're going to be here for a little while. How much confidence can we have in this aging of this crater at about 1,000 years? Judging from your blog entry, not much. Well, it's reasonably exact for geology, but not very exact in human terms. It's not 100,000 years old. It's much younger than that.

It's not 10 years old because it doesn't have the light rays, so it's much older than that. So you kind of split the difference in a logarithmic way and you arrive at an age of about 1,000 years. So it's probably somewhere between maybe 500 and 5,000 years old, maybe up to like 20,000, but it's just a ballpark age. Happy to be back in the ballpark with you and we'll visit with you again next week. All right, look forward to it, Matt. Emily Lakdawalla is the science and technology coordinator for the Planetary Society, also a planetary geologist, and as of recently, a contributing editor to Sky and Telescope magazine. Here's Bill. Hey, Bill Nye, the planetary guy here, vice president of the Planetary Society. And this week, of course, the NASA budget came out and everybody's arguing about that. By the way, everybody, we need a deep space rocket.

That's what the United States should be pursuing. Deep space rocket. You can argue about Aries and constellations and everything, but it's deep space. That's the word we're looking for. Meanwhile, I'm so excited about shallow space. shallow space. In 1960, you may remember Captain Joe Kittinger jumped out of a balloon at 19 miles above the earth and landed okay. He dove down like a skydiver and slowed down enough to open a parachute and landed. Well now, Baumgartner, an Austrian skydiver, has said he's going to make another attempt from 22 miles, 36,575 meters above the Earth's surface. He's going to jump out in not like a scuba suit or a pair of janitor coveralls, but in like a spacesuit, a very tight-fitting spacesuit.

And he will break the speed of sound for quite a while. Then he hopes to flatten out like a conventional skydiver and open his chute and come back to Earth. And let me just say, how cool is that? And then from a practical standpoint, if you're an astronaut, cosmonaut, taikonaut, other type of not, and you have something going wrong with your spaceship and you want to be able to just jump out, well now if this research goes properly, it will be possible. See, the whole thing got me because I used to see this exhibit about Kinninger, the guy who jumped from 19 miles, at the Air and Space Museum in Washington, D.C., when the Air and Space Museum was nothing but a Kwanzaa hut, a galvanized steel half circle. Well now, as you

may know, the Air and Space Museum is the single most popular museum in the world. More visitors than even the Louvre. It's astonishing. And it all started for me with guys jumping out of balloons miles above the Earth's surface. I gotta fly, Bill Nye the Planetary Guy. The Mars Exploration Rover team made it official last week. Mission leaders, including Project Manager John Callis, told us in a news conference that Spirit has finished her days of rolling across the surface of the Red Planet. Ah, but the rumors of her demise have been premature. I sat down with John in his office at the Jet Propulsion Lab a couple of days later.

We mostly talked about plans for Spirit, but I began by asking him about her sister on the other side of Mars. Opportunity is in the midst of one of the greatest sojourns in all of human history. Opportunity is doing very well. The rover has traversed over 19 kilometers so far. This is well beyond the original one kilometer design capability for the rover. So, you know, we're well past warranty on both these rovers. But Opportunity seems to be in very good health for considering her age. And she's on a great track towards another giant crater. You know, we think of Opportunity as the crater explorer. She landed in a small

crater, Eagle Crater. She traversed to Endurance Crater, which was about a 160-meter diameter crater. She then took the very long multi-kilometer trek to Victoria Crater, which was an 800-meter diameter crater. And that's still not enough for her. And now we're headed towards the largest crater yet, Endeavor Crater, which is 12 to 20 kilometers in diameter. Wow. Still some 12 to 15 kilometers away. So we have to more than double the odometry on a rover that's already well past warranty to get there. One of the exciting things that's happening right now is she's at a small crater called Concepcion.

And Concepcion is likely the youngest crater that we will ever have a chance to visit on Mars, at least with these rovers. youngest crater that we will ever have a chance to visit on Mars, at least with these rovers. It's of the order of about a thousand years old, which is brand new in geologic terms. It's only about 10 to 20 meters in size. So this is an exciting opportunity to see if we could find remnants of the original impactor and to understand more about impacts and what causes them and what clues or signatures are left behind. So we're very excited about that right now. I would imagine Steve Squires is, yes, very excited about that. But he's also very excited about what spirit is going to be up to, assuming that you're able to

successfully get through this winter ahead of you. Recap for us what the situation is right now and what the priorities are. I guess a big part of it is making sure you catch as much sun as you can. That's right. Spirit is very challenged right now on many, many fronts. As many of your listeners probably know, about 10 months ago, Spirit became embedded at this location we call Troy. About four years ago, Spirit lost functionality in its right front wheel. And because of the design of the rovers, when a wheel fails, it doesn't freely spin. It's locked in place.

It's kind of like one of those grocery store shopping carts where the wheel doesn't spin. I hate those. We do too. But she's still done a tremendous amount of exploration. And actually, because of that failed wheel, we made perhaps the most significant discovery with Spirit, which was this amorphous silica, which is an indicator of ancient hydrothermal systems on Mars, ancient hot springs. But Spirit was traversing in this location called Troy and broke through a crust. The geologists call it a dura crust. It's kind of like, you know, if you've ever walked on hard-packed snow and then suddenly you break through that snowy crust into the soft material underneath.

And so Spirit became embedded in this loose, unconsolidated material and has been struggling now for 10 months in trying to get out. We engaged in a very ambitious ground campaign where we recreated those situations at a test facility, a sandbox here at JPL. And we did tests with two of our rovers to try to figure out the best way to get her out. But yet another setback has occurred to that rover. Another wheel has stopped working. On the same side. That's correct. This is now the right rear wheel. So we're now a very asymmetric four-wheel drive

rover. And so that has complicated the prospects of getting the rover out much, much further. So that has complicated the prospects of getting the rover out much, much further. That's where we have been focused. Now, we are under the gun because the winter is coming. Spirit went into this with very dusty arrays. Then a wind gust came through. Actually, it was about the time we became embedded. Cleaned off our arrays pretty well. So we're not as dusty right now as we were at the last winter, but we're stuck at an unfavorable tilt.

We're in the southern hemisphere, or Spirit's in the southern hemisphere. The sun will be in the north, and so we would prefer to tilt the rover to the north as we've done for the past three winters. Right now, Spirit is stuck tilted to the south, so at a very unfavorable attitude. So if she remains at that attitude, there is a real question about surviving the winter. And so the efforts right now and the efforts for the next couple of weeks will be to see if we can modify the rover's tilt. Use the limited mobility that we have with the rover to try to tilt the arrays closer to the north. What is likely to happen during the winter is that we'll run an energy deficit. What I mean by that is that the rover will consume more energy than is being provided by the solar arrays.

And the only way the rover can do that is to steal it out of the batteries. So what will happen over time around the middle of the winter is that the batteries will become depleted. When they become too far depleted, it causes a fault on the rover. You know, just like your camcorder, when the batteries are getting low and that little red light starts to blink, well, when the batteries get low on the rover, the rover realizes it's in a very dire situation, and so it shuts down everything. So what will happen is the rover will shut down, leaving only the clock, the master clock running, and the batteries connected directly to the solar array. So the batteries will attempt to recharge, but what that means is that the rest of the rover

will start to get colder. And we are expecting to see colder temperatures this winter on the rover than we've seen previously on Mars. Now, the rover was designed to go through cold temperatures. It's designed to withstand minus 40 degrees C, 40 degrees Celsius internally to the electronics when it's operating and get as cold as minus 55 degrees Celsius when it's not operating, when it's shut down. And so we're likely to see temperatures between those two numbers for the rover. But those allowable temperatures were for a brand-new rover fresh out of the box. Spirit's been on the surface of Mars for over six years and has gone through thousands of thermal cycles. And so it's an old rover.

We can't say whether it will tolerate those colder temperatures we're likely to see this winter. Again, she's designed, originally designed to, but that was for a brand-new rover. Mars Exploration Rover Project Manager John Callis. We'll hear more about what's in store for Spirit when Planetary Radio continues. 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.

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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. My guest is the Jet Propulsion Lab's John Callis, project manager for the Mars Exploration Rovers, Spirit and Opportunity.

I visited John's office last week to hear about Spirit's future. Stuck for good in a Martian sand trap, Spirit faces a winter of, at most, sunlight that is barely adequate to keep her batteries charged. She's also apparently not going to be able to phone home every day because of this power deficit. That's right. I mean, one of the things the rover will do is shut down all systems on the rover that aren't absolutely essential to keeping the batteries charged. Basically, powering off your laptop and pulling the battery out and just sticking the battery in the charger while your laptop sits unpowered. That, of course, means that the rover

won't talk to us for a while. And it may be of the order of several months. It might be like six months that we don't hear from the rover. The rover will be in a deep state of hibernation. And what happens each day is the rover has her clock running and it sets a timer for a time into the future. And when that time occurs, about a day later, the rover has some of its electronics to check whether the batteries have charged enough to whether it can wake up or not. If not, it goes right back to sleep. And it does that each day. If it does have enough to wake up, it will then power up and be able to support a communication session with the Earth.

And so we have to be prepared to talk to the rover when that happens, but we won't know what day that will happen. So we'll have to be prepared pretty much almost every day to see if the rover when that happens, but we won't know what day that'll happen. So we'll have to be prepared pretty much almost every day to see if the rover talks to us. But we're expecting we'll go through several months of silence and not knowing. And of course, if the rover doesn't survive, we won't know right away. We'll just have this extended period of silence, and that's going to be very challenging. But it's not sleep. At least you hope it won't be. Excuse me, it is sleep. It's not death. We're not talking about Phoenix here. Oh, no, it's not like Phoenix. Again, the rover has shut down all its systems. Its computer is shut down. But the power system is working to charge the batteries, and the clock is running,

and the clock triggers periodic wake-ups of the rover. It's a deep hibernation. It's kind of like a polar bear going into an ice cave for six months and just sleeping that whole time. Bear's not awake, but certainly the bear is not dead. And when the spring comes, both should wake up. Devoutly to be wished. We only have a couple of minutes left. I want you to talk, though, a little bit about when that wake-up call arrives, and spirit is still stuck there. I was going to call this the sand trap from hell, but if it's hell, it's probably the kind of place you'd want to be. Steve Squires in the press conference was really excited about the science that this little no longer a rover is going to be able to conduct as a stationary station? Oh, there is tremendous science. The adventure and exploration is by no means over for Spirit. One of the most important scientific objectives we can pursue with Spirit is to carefully track

the radio signal from the rover while it's stationary, because a stationary rover is now locked to the planet. And so by tracking the radio signal on the rover, we are tracking the motion of Mars. And this is one of those Doppler miracles that a lot of spacecraft have performed? Yes, that's right. What we're going to do is look at the Doppler signature from the radio signal to ascertain the very precise motion of the planet. Mars has a wobble to it. It has a precession and a nutation. And the nature of that wobble is indicative of the geometry of its interior. How big is the core of Mars and whether it's liquid or solid?

The analogy I would make with this is the old trick of finding out whether an egg is raw or hard-boiled is you try to spin it. And if it sloshes, it's raw. And if it spins nicely, it's hard-boiled. Well, we're going to do that with Mars. If it sloshes a little bit, in other words, if there's this wobble in the Doppler signature, then it's perhaps indicative of a liquid core. If it's more solid in its behavior, then that tells us a lot about the evolution of the planet. And that's an exciting discovery. And it's kind of strange when you think we're sending a mobile rover to the surface of Mars to actually tell us about the geophysical properties of the

interior of Mars. And so that's a great science objective, and that's what we're going to do next. Still great surface geology in store as well. Judging from Steve's excitement over this sulfite, the stuff that actually got Spirit in trouble in part, is pretty fascinating. Yeah, well, you know, Steve Squires is not the only person excited by all this. You know, we've been joking that the location where Spirit became embedded is analogous to having your car break down next to Disneyland. And so it has been Disneyland for the geologists. This is a scientifically very exciting site. What has made these materials so difficult for the rover is scientifically interesting.

These are assessed to be recently remobilized minerals. So they're minerals that formed a long, long time ago, perhaps when home plate formed billions of years ago. But they've been transported since they formed. And one of the theories, one of the leading hypotheses is that during the last obliquity change, the last change in tilt of Mars, that there may have been snowpack at this location. And at the bottom of the snowpack, you can get ice melt.

So even though Mars doesn't have enough atmosphere to support liquid water on surface, if that liquid water is buried under an ice pack or snowpack, it can be liquid. And so they think that the liquid water, what they call a solid state greenhouse effect, melted that ice under the snowpack and remobilized or transported these very soluble sulfate minerals. Fascinating. Very exciting stuff. Yeah. So Spirit has found evidence of two different epochs in which there was liquid water on the surface of Mars,

one ancient and one more recent. Six years and counting, you met your mission goals in the first year, I would say, You met your mission goals in the first year, I would say, but still discovering amazing things about this absolutely fascinating planet. Well, that's the great beauty of a roving mission is every day is like a brand new mission because we move to a new site, a new location. We're not staring at the same real estate. Beyond the scientific discoveries that these rovers have made, for me, I'd say their greatest contribution is that they have made Mars a familiar place. Mars is no longer this strange, mysterious planet. It now exhibits characteristics that are familiar to us here on Earth. Those of us who are privileged to work on this project essentially go to work on Mars every day. And that is a magnificent story.

I'll go even further and say that I think that you have inspired the public regarding science and exploration in ways that probably have maybe not been equaled by any other spacecraft, maybe equaled, but certainly not surpassed. I'm glad that you're going to be able to keep doing that. Best of luck in getting Spirit ready for the winter and with opportunities, trek off to that very exciting and very large crater. Well, thank you very much. John Callis is the project manager for the Mars Exploration Rovers. One of them no longer a rovin', one of them still very much so, but both of them still promising great science as they unveil more and more of the red planet to us.

We'll unveil the night sky as we pick up with Bruce Betts for this week's edition of What's Up. That'll be in just a few moments. So it is time for What's Up on Planetary Radio. Here's the director of projects for the Planetary Society, Dr. Bruce Betts. You know that when I go to JPL, I always stop at the souvenir shop. I love it when you go to JPL. Okay, you ready? So nice. I am.

Let me reach this side here. Gold bullion? No, but very, very close. You don't know how close you are. JPL jelly beans. Oh, you laugh. Those are practically the same. That's awesome.

And they're in a JPL labeled jelly bean shaped plastic case. Sort of aluminum. Yep. I have not seen those. These contain genuine unobtainium. Really? I'll slide it over to you. Thanks. So you weren't far it over to you. Thanks.

So you weren't far off with the gold bullion. You're welcome. As always, your gifts are awesome. My pleasure. What's up? Speaking of awesome, Mars opposition occurred on January 29th, opposite side of the Earth from the sun. Closest approach to Earth was right around then, a couple days before it, due to the elliptic nature of the sun. Closest approach to Earth was right around then, a couple days before it, due to the elliptic nature of the orbit. But the important thing is Mars remains super bright, almost as

bright as the brightest star in the sky, Sirius. And if you look in the east after sunset or any time in the evening, it'll just keep getting higher in the east. You will see a reddish, yellowish, bright star-like object. That's Mars. And then turn a little to your right, and you will see Sirius, the brightest star in the sky, which is very blue in color. A lovely contrast. Don't miss it. If you have a decent telescope,

you can check out Mars' north polar cap as well. Sirius, brightest star in the sky, or is that? You're right. The sun is the brightest star in the sky. Oh, yeah. But second brightest is indeed Sirius. Okay. I thought that's what you were going to pick me on.

No. No, I wasn't after you. Not yet. So check them out. And Saturn also coming up in the east later in the evening and looking kind of yellowish and not nearly as bright, but still like a bright star, and you can see it high in the south before dawn. On to this week in space history, and it is a week to remember in a negative way, but courageous. The three U.S. space disasters all occurred between last week and this week.

The Challenger accident, the Columbia accident, and the Apollo 1 fire. Hard to believe that we've come around to that again, and also incredibly sad and hard to believe how freakish this is, but there you go. It all occurred within a few days in the calendar year. Separated by many years. Yeah. On to something a little bit lighter. In 1974, Mariner 10 executed the first gravity assist during this week,

flying by Venus on its way to Mercury. first gravity assist during this week, flying by Venus on its way to Mercury. We move on to Random Space Fact. Very nice. Had a sort of 30s swing feel to it. Oh, thank you. Of the 50 nearest star systems, they would be within 17 light years from earth the sun ranks fourth in mass huh you said 17 so within 17 light years 15 nearest stellar systems sun is actually fourth

in mass despite being you know kind of average but it's it's bigger than that all right all right we're number four we're number four so we beat alpha centauri right right? That's a small, those are small stars, that system. Yes, we won the Alpha Centauri. Smackdown! Smack Pandora. So anyway, we move on to the trivia contest. And in a blast from my science past, I asked you about weird physical units. I asked, what are the units of thermal inertia? I asked, what are the units of thermal inertia?

It's something used commonly in planetary science to measure the resistance to heating of a periodically heated surface, like a rotating planet. And so things with high thermal inertia heat and cool more slowly than things with low thermal inertia. Low thermal inertia is like fluffy dust. Then you have sand in the middle, and then a rock would be a low thermal inertia. Low thermal inertia is like fluffy dust. Then you have sand in the middle, and then a rock would be a high thermal inertia. And then you get to politicians. Exactly. But it's interesting.

It's the reason that if you go out during the day and touch a rock, it'll be cool compared to the surroundings, or at night it retains the heat. Yeah. But it's cool, so to speak. But what's super weird is thermal inertia, which falls out of equations for those playing the equation game as the square root of k rho c where k is the thermal conductivity rose the density and c is the specific heat gets these super weird units and yet it's

something physically interesting what are the units matter would you like me to share would you please because and then i'll tell you who won. I mean, talking weird, weird squared, weird cubed. No, it's worse. It's weird to the minus one half. In SI units, it is joules per square meter per degree Kelvin, or per Kelvin, excuse me. And here's the super weird one, per second to the one half. We also had people tell us that the other measure,

the other name for this unit is TIU, which is thermal inertial unit. But, as several people pointed out, TIU2, I guess, is also the old English word for Mars. Cool. So it all works out very clever. I never once ran into that expression until you told me people were sending. Chris Chisholm. Hey, Chris, you won. You're going to get that book, Traveler's Guide to Mars, signed by William Hartman. Chris hails from Newcastle-upon-Tyne in the United Kingdom. Don't you love it?

Cool. Newcastle-upon-Tyne. I just love it. All right, we'll take a different direction this week with the focus on Mars rovers. we look back to a competition run by the Planetary Society with Lego for NASA that generated names that they then selected Spirit and Opportunity from. So my question for the people out there, what was the name of the, at that time, nine-year-old girl who submitted the winning entry, Spirit and Opportunity? Go to planetary.org slash radio. Find out how to enter.

What are we giving away this week, Matt? I think we're going back to T-shirts. We're going to have some other cool stuff coming up soon. Very, very soon. Oh, like a Planetary Radio T-shirt isn't like the coolest thing. Well, you know what? We actually had a couple of people say, if I win, can I have the shirt? But yes, this is your chance once again to get a Planetary Radio t-shirt.

And you have to get it in to us by the 8th of February, Monday, February 8th at 2 p.m. Pacific time. All right, everybody go out there, look up at the night sky and think about low thermal inertia dust. Achoo! Thank you. Good night. Good night. He's Bruce Betts, the Director of Projects for the Planetary Society. He joins us every week here for What's Up. Lou Friedman on the new NASA budget and plans for human spaceflight.

That will be our topic next week on Planetary Radio, which is produced by the Planetary Society in Pasadena, California. Keep looking up. Thank you.