Planetary Radio: Space Exploration, Astronomy and Science - The 7th International Conference on Mars

Episode Date: July 16, 2007

500 members of Earth's Mars appreciation club gathered at CalTech in Pasadena, California last week. Scientists presented the latest research on Mars.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Not heaven, but Mars on Earth, 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. I'm Matt Kaplan. We begin several weeks of related coverage with this episode of our show. You'll hear from former JPL Director Bruce Murray, Kenneth Tanaka of the United States Geological Survey on digging down through the polar ice, and Greg Delorey of UC Berkeley on a new way to discover water deep under the surface. Next week, we'll take you to a celebration of Mars that honored beloved author Ray Bradbury. We've also got a brand new non-Martian Q&A from Emily Lakdawalla this week, and a special Mars

conference edition of What's Up with Bruce Betts. That's at T-minus 20 minutes and counting. Let's hold that countdown for a few space headlines. Space Shuttle Endeavour has made it to Pad 39A at the Kennedy Space Centre. NASA is hoping for an early August launch on an 11-day mission to, where else, the International Space Station. What if extraterrestrial life was sitting in front of our noses, but we couldn't recognize it? That's the fear addressed by a new report from the National Research Council. The NRC says we may be spending too much effort on finding life that looks like us, at least chemically. Ammonia-based life? Silicon?

It's no joke. You can learn more at planetary.org. Then again, there's nothing wrong with water. Research just published in Nature documents the discovery of water vapor on an extrasolar planet. Vapor is the key term here, since planet HD 189733 b broils at about 1,000 degrees Kelvin or 1,300 degrees Fahrenheit. That's some hot tub. Here's Emily with some Trojans that won't infect your computer or score touchdowns.

I'll be right back to begin our coverage of the International Conference on Mars. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, Will New Horizons be able to explore any Neptunian Trojans on the way to Pluto? First, I'd better define what Trojan means here. Wherever a massive body orbits another one, like a planet around the Sun, there are five special points where tiny bodies can sit in gravitationally stable positions.

These are called Lagrange points. Two of the Lagrange points, called L4 and L5, lie 60 degrees ahead and 60 degrees behind the orbiting body. A century ago, the first asteroid was discovered in Jupiter's L4 region. As more of these asteroids were discovered, they came to be named after participants in the Trojan War. Now they are collectively called Trojan asteroids. Trojan asteroids have also been discovered in Mars and Neptune's orbits.

It turns out that, fortuitously, New Horizons' path to Pluto will take it through Neptune's L5 region, the Lagrange point that follows Neptune in its orbit. Will New Horizons get to study any of these distant dark bodies? Stay tuned to Planetary Radio to find out. Almost everyone who is anyone in the Mars science community was in Pasadena last week. Over 100 formal presentations were crammed into the 7th International Conference on Mars at Caltech. But there were many more worthy topics found in the poster sessions outside in the California sun.

A poster session is just that. A poster session is just that. Researchers stroll among aisles of bulletin boards, each hung with lovingly produced text, charts, images, and conclusions about the red planet, and each tended by a scientist ready to talk about the work that may have occupied him or her for months or years. Some attract little attention. Others are clogged with excited colleagues questioning, admiring, or disputing the findings in front of them. One of the more popular spots was staffed by Kenneth Tanaka, a planetary geologist with the United States Geological

Survey in Flagstaff, Arizona. Ken's boards displayed beautiful renderings of the Martian poles. Bruce Murray was one of the admirers. Dr. Murray was director of the nearby Jet Propulsion Lab three decades ago and is an emeritus professor at Caltech, where he has been a member of the faculty since 1960. He's also a founder of the Planetary Society. You had Dr. Murray here absolutely spellbound in your presentation you're giving here at the poster session, talking about the, what, stratigraphy of the pole regions on Mars? That's correct. So it's the sequence of rock units that we see recorded in these plateaus that cover both poles.

And from that, we hope to gain a view of the climate record on Mars. And so that's why there's so much interest in these features. Is this at all analogous to the ice coring that can be done on the poles on Earth? Very closely, yes. We see layers in the ices on Earth and at the poles. And the same thing here. We see layering structure in the Martian polar deposits as well. How are you getting your data? It must be essentially from orbiters at the moment.

I mean, Phoenix, the first polar lander, doesn't launch for another month or two. That's correct. This is all orbital data sets that we're using. But there's a rich variety of data, and we're still receiving a lot of it and will continue to. So there's enormous amounts of data that help us to look at the surface landforms and what are their compositions, and even what the subsurface structure might be through the ground-penetrating radar instruments. So you're discovering the structure at both poles.

Is that structure beginning to unlock climate secrets about this planet? Well, often when we do this work, we develop new questions as we go. Often? I thought it was always. All the time. Often? I thought it was always. All the time. And so what I'm seeing, at least my interpretation, is that there is a richness to both the climate and geologic record in these deposits that is increasingly complicated.

And so it means, I think, that our understandings have to adjust to that complication. I think we're further removed from understanding it because of that. This sounds almost like a story you were telling me, Bruce, about the more you learn. And since you seem to be so fascinated by this, I guess the polar regions of Mars have always been a big interest of yours. Yes, that's where the action is, and if you're interested in climate change, then the record should be at the poles, water and carbon dioxide. So they're especially important and relatively easy to image and get a hold of. So this work that you're hearing from Ken is pretty exciting.

Yes, very exciting. And this reflects JPL, it reflects the United States Geological Survey, huge institutions. This is not an easy thing to do. But when you can sit at the end of that and receive the results, it's very exciting. Where would you say the status of this is? I mean, what would you like to see happen next?

Well, I think it's been brought out at this conference that we have this rich data set, which obviously will take us many years to digest and try to understand. So we have a lot of work to do with our current data. So that's of immediate concern is to continue to gather data with the current instruments and to collate that and try to start digesting it. And then there's the thought of where does that lead us to, what kinds of investigations are necessary to go further with our interpretations.

And some of the ideas would be to have landers of different sorts, perhaps ones that could measure the surface atmospheric parameters like wind speeds and the moisture in the atmosphere, the CO2 and so forth, and what's going on

seasonally and over longer time scales. As well as actually investigating the IC layer deposits themselves, having a lander that, for example, that could drill down a ways and see if there's a climate record that could be unlocked. So I'll post a right up the aisle here that is a proposal for a drill that might be able to provide some of that information. It's a good time to be a planetary scientist.

I would ritually agree with that. Well, I think what Ken is talking about is extremely important because the first phase in planetary exploration is remote sensing and imaging like we've been doing. But the next phase is getting on the ground and digging, drilling, whatever. And it doesn't require humans to do that. Robots get better. The doubling time for robotic capability

doubles every two or three years. The doubling time for human capability is thousands of years. So the future belongs to robots, and the service of Mars really belongs to the robots. It's going to be a very exciting time. And lots left to do. Very much so.

And I want to thank Dr. Murray because he was one of my professors here at Caltech many years ago. So he's responsible for my work in more ways than one. Sometimes I think about half the people here could make that statement. Well, this makes me feel old.

Thank you, gentlemen. Thank you. That's planetary scientist and former JPL director Bruce Murray with Kenneth Tanaka of the United States Geological Survey. We need to take a break. We'll return to the poster session at the 7th International Conference on Mars

for a visit with UC Berkeley's Greg DeLore. This is Planetary Radio. Hey, hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era. Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration. You probably do too, or you wouldn't be listening. Of course, you can do more than just listen. You can become

part of the action, helping us fly solar sails, discover new planets, and search for extraterrestrial intelligence and life elsewhere in the universe. Here's how to find out more. 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. Well, if you hear the noise around us,

it's because we're at the poster session here at the International Mars Conference. And standing next to one particular poster with its creator, someone I think already known to much of the planetary radio audience, Greg Delorey, who has been involved with the Mars microphone and solar sail, right? That's right, two of the Planetary Society projects that I've been lucky to be involved with. But this poster is something altogether different that you've been working on, and it is a technology that you're pioneering, I guess,

and if it works and was deployed, it could actually maybe detect water as deep as a kilometer below the surface of Mars. That's right. That's the gist of what we're after here. Water being one of the most important aspects of the Mars environment in terms of understanding the climate history, in terms of understanding its habitability for microorganisms or more complex organisms in the past. We know that Mars may have been warm and wet at some point. The question we're trying to answer here is where did that water go? And one location could be in the subsurface. And it's important to note that we know that there's water on Mars in the form of ice.

And what this methodology will tell us is where is the liquid water? A really exciting discovery would be the depth and thickness of subsurface water, analogous to groundwater you'd find on Earth. Again, it would have implications for astrobiology, also as a potential resource for future explorers. And just understanding how Mars works as a planet in terms of its hydrological cycle and the role that water has played throughout its history. How does this technique differ from the radar instruments that have already tried to detect subsurface water from orbit? Yeah, that's a good question.

And this technique is, you can think of it as the other radar. This technique also uses electromagnetic waves to detect what's beneath the surface. Radar operates in high frequencies, and what it does is it shoots waves down to the surface, and we look at reflections coming back from discontinuities in the subsurface structure, and we get pretty high-resolution, detailed information about layering and about the subsurface structure. But it turns out radar is not optimum for detecting really interesting targets such as liquid water, which don't stand out from rock and other substances as clearly as one would like. Radar can find water, but it's not as sensitive as some other techniques.

So what we propose to do is use electromagnetic signals of much lower in frequency. They're no longer reflecting from the surface of Mars. These signals actually penetrate in and diffuse into the subsurface of Mars, and they generate electrical currents in the ground. And we monitor the electromagnetic fields that are generated by these currents, and that information can tell us when there are conductors in the subsurface. These are natural currents. This is a passive system. That's a good point to bring up, that most planets have a natural background electromagnetic environment. So we leverage that to use as our signal. And we can tell from the behavior of these signals near the surface what conductive features are beneath the surface. And because liquid water is very

conductive electrically compared to other properties and surfaces around it, it stands out very clearly in the data. And it's fundamentally different from radar in that respect because radar doesn't really sense the conductivity. It senses the dielectric constant. Describe this. You've got a sort of central electronics unit, but there are these little outlier sensors. This is analogous to a couple of scientists doing a geophysical survey on Earth. And so they would bring out a little electronics box, which we have here, that contains all the power and data system for taking in the data and analyzing it. And then we take little voltage probes that measure literally the potential across the ground,

separated by a few tens of feet. And that tells us what the electric field is at the surface. And then we also drop off a little magnetic field sensor, which tells us what the magnetic field is at the surface. And when we take the ratio of the electric and magnetic fields, and that tells us directly what the connectivity of the subsurface is. It's a very sensitive radio, at least the electrical part of it is. It's a low frequencyfrequency radio. The planet is talking to us. What kind of frequencies? How many hertz are we talking about here? Well, some of the signals are below a hertz.

Now, this particular system covered the audio range, so from about 5 hertz to 20 kilohertz in frequencies. Human hearing. That's right. We call it audio magnetotolerics. That's the technical designation. However, it's quite within our capability to extend the frequency response down to below a hertz, which will give us much deeper penetration into the surface of Mars, and we could probably image down to 10 kilometers. And you've created for this some new, very sensitive sensors, amplifiers?

The main challenge was to reduce the size of the magnetic field sensor, which typically is 3 or 4 feet long in Earth-bound applications, and so we brought that down to 18 inches. And we developed a new generation of voltage sensors that rely on sophisticated electrometer circuits inside the sensor to actively measure what the surface potentials are. And you've tested this on Earth. Yes, we went out to the Eastern Snake River Plain in southeastern Idaho, which is near the Craters of the Moon National Monument.

It's a very interesting site because it's the site for a young lava flow. And because it's young and because it's lava, it presents an electrically resistive barrier near the surface that we can use as an analogy to the permafrost on Mars, which will also be very electrically resistive. So it's like a resistive barrier that we use as a test case to see that our waves can penetrate through and detect conducting targets beneath that barrier. And in the case of Idaho, we found the water table at about 200 meters beneath the surface, and we also found a transition from the young lava to the old lava at a kilometer.

And so this tells us that we can discriminate subsurface structure based on conductivity. Clearly the technology works. You've even tested it with essentially a rover showing how a rover could deploy it. It sounds like you've dealt with or nearly dealt with all of the science and engineering, but then it may be just as big or a bigger challenge getting this as part of the payload for some upcoming mission. Well, that's certainly what lies before us, and we're here showing our results, showing the power of this elegant, simple technique for deep subsurface penetration on Mars in the hopes that the community will understand its utility and will have some priority for a

future geophysics mission to Mars. Particularly liquid water being our target, I think, makes us very relevant because that's a central theme in almost all of the investigations happening on the Red Planet right now. And you're obviously in the right place to do that lobbying, if you'll pardon the expression, because everybody's here. I prefer the term discussing, but lobbying will work. We're here to spread the news and show what we've done, and we hope that the community sees value in it. Good luck, Greg. Thanks so much.

Greg DeLore is a senior fellow in the Space Sciences Laboratory and Center for Integrative Planetary Sciences at UC Berkeley. We spoke with him at the 7th International Conference on Mars, held last week at Caltech in Pasadena, California. Our coverage of the conference and events surrounding it will continue next week as we join scores of fans honoring Ray Bradbury. The author of the Martian Chronicles got to pick a spot on the red planet that was imaged by the Mars Odyssey spacecraft. We hope you'll join us for the presentation of that image to Ray.

I'm Emily Lakdawalla, back with Q&A. On its way to Pluto, New Horizons will be passing through Neptune's trailing Trojan region in 2014. Trojan asteroids of Neptune are dark, icy, ancient bodies similar to Kuiper Belt objects, which is exactly the type of object that this spacecraft is designed to study. The catch is that we haven't yet discovered any asteroids lying in this gravitationally stable region on Neptune's orbit. Four Trojan asteroids of Neptune were recently discovered in the leading Lagrange region, but none have yet been found in the trailing region. The search is on to find targets for the once-in-a-lifetime chance for

a spacecraft to perform observations of a Neptune Trojan, but the trailing Lagrange region and New Horizons path just happens to be near the Milky Way in the sky at present, making it difficult to pick out tiny dark bodies from among the glare of background stars. Neptune's 160-year orbit means it will be a long wait before the trailing Lagrange region moves into a darker part of the sky. Still, with five or six years to search, astronomers may yet discover some new Neptune trojans just in time for New Horizons to send back our first views of these ancient relics of the formation of the solar system. Got a question about the universe? Send it to us

at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Bruce, it's break time here at the International Mars Conference. Obviously the best possible time to do What's Up. Exactly. So let's to do what's up. Exactly. So let's tell you what's up. You know, Mars is up. Do we need to know anything more? We're at the Mars Conference.

Say it louder and maybe everybody will jump up and down and cheer. Mars is up! All right, but Mars is still kind of dim, but you can see it in the pre-dawn sky over there in the east. Looking reddish. It will brighten up over the next few months. In the evening sky, Venus and Saturn dropping. Saturn dropping even faster towards the horizon,

but after sunset you can still at least pick out Venus really easily as the brightest star-like object in the west. And Saturn below it, looking much dimmer. And on the other side of the sky or in the south, the really bright object is Jupiter. And if you look below Jupiter, a little ways, 5, 6 degrees, you'll see a reddish star. That is not Mars. That is Antares, the big giant supergiant in Scorpius. So there's a star for you.

All right, good. Thank you. I feel much better. Now the sky is complete. Well, there are a few other stars, but we don't want to run out. What else you got? I don't want to scare anyone walking by, but I do have random space fact! They didn't even budge.

That's because they're all huge fans. They're just used to it. The dwarf planet that isn't so dwarfy, Eris, now pretty well shown to be bigger than Pluto, it has a pretty elliptical orbit out there. Right now it's a balmy, well, okay, it's not really balmy. It's 400 degrees, minus 400 Fahrenheit. You know, 70, 50 Kelvin, something like that. Really, really cold.

But the interesting thing is 250 years from now, if you wait around, it'll come closer. It'll be like up like 40 degrees. Talk about global warming. Okay. Well, we'll be sure and catch that because about that time we'll be ready to open a resort. Oh, that's a good point. On Eris. Yes. Yes. In the meantime, let's go to the trivia contest. We asked you what was the fourth spacecraft to orbit the Earth? The fourth spacecraft to orbit the Earth. How did we do? Tremendous diversity of answers here, and I'm not really sure why it was so difficult.

A few people found a good timeline, laid out all the spacecraft, and boy, were there a bunch of American spacecraft that blew up. Oh, yeah, it was fireworks, fireworks all the time. Man, we could not win for losing. It was just awful. Yeah, there was kind of a slow start to the launch program. So, of course, you know, our first success was Explorer 1, but prior to that was Sputnik 1 and Sputnik 2. So what was the next American success? No, it wasn't Project Score. No, it wasn't Explorer 3, as a lot of you said. It was Vanguard 1. Indeed, that's certainly my impression, Vanguard 1.

But after a few months of U.S. and Soviet failures in between the first launches. And do you know what a lot of people pointed out? If they got Vanguard 1, just about everybody who got the answer correct also added, and it's still up there. Yes, this is, as I understand it, the spacecraft that's been in orbit the longest of any spacecraft out there. Yeah, and it's got hundreds of years to go. That's really pretty wonderful to think about.

That is pretty cool. As long as it doesn't, you know, like hit the windshield on a shuttle someday or something like that. Wow, there's a happy thought. No, they have a really good idea of where it is. That's the good news. I think it's trackable. That's what our friends at NORAD do. And one of those who did get Vanguard One made that his choice.

And then Random.org made him our choice is Al Navarro. Al Navarro of Manchester, New Hampshire said Vanguard One, sure enough, still in orbit. And he said, I'm sure the Earth was none too pleased to hear that it's pear-shaped, which the measurements of Vanguard One's orbit showed. Apparently, Khrushchev called it a grapefruit satellite. He says, I haven't eaten lunch yet. Well, congratulations to that fruity response. I think Al wants to write comedy for us.

Somebody better do it. Goodness knows we need it. Give us another happy thought. Oh, you didn't really want a happy thought. How about a trivia question? That'll do. All right. Trivia question.

I'm going to take you into the strange land of programmatic planning in the space program. Science planning. I'm sure all of you know already, but if you don't, look it up. What does the acronym MEPAG stand for? We've had some MEPAG-related presentations here at this meeting. What is MEPAG, M-E-P-A-G? What's the acronym, and we'll tell you more about them later. We'll definitely do that. And we'll give you until Monday at 2 p.m. Pacific on July 23rd.

That's the deadline this time, July 23rd, that Monday at 2 p.m. Go to planetary.org slash radio. Find out how to enter if you haven't done it before. Yeah, that's good to know, too. All right, we've got one other thing to mention, and that is the pictures that came in of the Great Conjunction. We got some very cool pictures, as you mentioned some last week. We got a couple different listeners submitted nice pictures of the Conjunction when Venus and Saturn were nuzzling in the sky, and so we're going to make some attempt to post those,

and I think we're going to give some prizes. What do you think? I think we should, yeah. Yeah, at least to John Lease, who we did mention last week, and took those really very nice images, I think, up at Griffith Park here in L.A., up at the Griffith Park Observatory,

recently reopened, out there with a lot of other people with telescopes trying to see what he was taking pictures of. Mm-hmm. And came out very nice. So, as I say, we'll try to post those and we'll get a T-shirt out to John and go from there. Any other comments you want to make about the International Mars Conference before we leave? Well, in strange seriousness, it's been an interesting week of new Mars discoveries,

and always good to see the old Mars crowd getting together for a week and be back on the Caltech campus. Not that I don't work five blocks from it all the time, but usually I only come over here to swim and play racquetball nowadays. So it's good to poke around some of the other parts. All right, Bruce. Well, probably a lot more people here you want to say hello to, so we'll let you do that. All right. Say goodnight.

Everybody, go out there, look up at the night sky, and think about giant buildings that look like wedding cakes. Thank you, and goodnight. Everybody go out there, look up at the night sky and think about giant buildings that look like wedding cakes. Thank you and goodnight. And there it is right behind us, the beautiful Beckman Auditorium on the campus of the California Institute of Technology. Birthplace of Dr. Bruce Betts, the Director of Projects for the Planetary Society,

who joins us every week here for What's Up. As we said, our coverage of the International Conference on Mars will continue next week with a reception for Ray Bradbury, who is as much a Martian as anyone on Earth. Planetary Radio is produced by the Planetary Society in Pasadena,

California. Have a great week, everyone. Thank you.