Planetary Radio: Space Exploration, Astronomy and Science - Getting a Rover's-Eye View of Mars

Episode Date: May 12, 2003

Hear excerpts of the Mars Exploration Rover imaging team lead Jim Bell's presentation last week at Planetary Society headquarters; Emily looks for life on the moon, while Bruce Betts says to get ready for this week's lunar eclipse!Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

This is Planetary Radio. Hi everyone, I'm Matt Kaplan. Mars looms large on this week's Planetary Radio, just as it is growing in the sky. Join us for a special talk by Dr. James Bell of Cornell University as he examines the recent robotic exploration of Mars and the most ambitious mission ever, beginning next month. We'll have that right after Emily tells us about the search for life near Earth, but not on Mars. Hi, I'm Emily Lakdawalla with questions and answers.

A listener asked, I've been following the debate on whether that Mars meteorite contains evidence of early life on Mars. I wondered if anyone investigated the Apollo moon rocks with the same zeal. As a matter of fact, a lot of work went into searching the lunar samples for organic materials. Organic chemicals contain carbon and oxygen and are considered along with water to be the building blocks of life. Scientists did find reduced carbon in the lunar surface layer, most of which arrived there from asteroids and the solar wind. At one time, papers reported the presence of small quantities of complex organic compounds, like amino acids, the building blocks of proteins, in the lunar samples. Sadly, these compounds proved to be artifacts of the researchers' analytical techniques and had not come from the moon at all,

so there is no evidence for complex organic materials on the moon. But, as they say, absence of evidence is not evidence of absence. Could there have been life on the moon? Stay tuned to Planetary Radio to find out. Jim Bell is a professor of astronomy at Cornell, where Carl Sagan once taught. And like Sagan, Dr. Bell is intimately involved with planetary exploration, with a special focus on Mars. Seven years of Jim's hard work are about to climax in the launches of the twin Mars exploration rovers. The golf cart-sized rovers carry the sharpest cameras

ever to land on the Red Planet, and he leads the team that develop them and will operate them. Last week he visited with an enthusiastic audience at Planetary Society headquarters. We're very happy to present

excerpts of his presentation on this week's Planetary Radio. Here we'll start with Jim's comments about how far we've come since the turn of the 20th century, when Percival Lowell's mysterious drawings of Martian canals fired the human imagination. Most of our current thinking and Mars in the popular psyche comes from this era, really comes from the turn of the century, the turn of the 20th century, when Mars got put into people's minds

as a place where there could be other intelligent beings. And in many ways, that way of thinking is still with us today. Even though we've gotten better data and we've sent space missions there and we haven't seen any little green men walking around. We still learned enough about this place to realize that it really does belong in a short list of other places in the solar system where we could talk about life.

And the spacecraft have converted Mars, have turned Mars from this fuzzy dot that you can see even in your backyard telescope into a real place with geology, this fuzzy dot that you can see in your backyard telescope into a real place with geology giant volcanoes, beautiful polar caps, enormous canyons, giant landslides. If you zoom into one of these cracks in these canyons in the polar cap, you can see this beautiful layering. And you can follow this layering for thousands and thousands of kilometers around the polar cap.

And it's bright dark, bright dark. This is all ice, mostly CO2, dry ice, but also some water ice in there. And this is dirt. And so if you went from here to there, you'd be going down a pretty steep hill to get down hundreds of meters or kilometers or so down into the floor of the valley here. And all along the way, you'd see these bands of icy, dusty, icy, dusty. On Earth there are places like this, in Greenland, Antarctica, other places, where you've got an ice cap and exposed in between the cap are layers because Earth's climate has changed.

You go through a century of extra warm or another century of extra cold, more snow, less snow. And you go to places like Greenland or Antarctica, and you go to places like this, and you put a drill down, and you pull up a core, and you look at that core, and you read the record of the recent climate history of the Earth. You see that there was 1,000 years of warmth and some giant volcanic eruption and then maybe an impact, you know, things like that. So pictures like this tell us that there are places like that on Mars, too.

There are places where you can go and read the record. If you could get some equipment there, this is another place on my list. I wouldn't bring a camera. I'd bring a big drill and pull this record up the last who knows how many million years, 100 million years of Mars history and see how it compares to Earth's history. So it's a fascinating place in an enormous number of ways. What's the geology like? And then life, of course, is there evidence for life on Mars now or in the past?

Or even are the conditions right now, or were they, conducive to life? Would they allow it? And all these three are at least on our planet and we think almost everywhere else in the solar system and in the universe are held together by water. Water is literally the tie that binds. It's responsible for life as we know it. Water is an important driver of the climate on our planet and many other planets and of course it's a very important resource. This is how NASA and many other space agencies look at the exploration of Mars,

and it's an index card way of saying everything that I've said right now. Life, climate, resources, find and follow the water. So that kind of set of goals and way of approaching it is driving the current missions that are there, like Mars Global Surveyor, which got there in late 1997, I believe, and has done some amazing things since getting into orbit. There is a beautiful camera that's taken some spectacular pictures, a tiny little area, part of an impact crater that looks like it has these beautiful water-carved features

coming out of it. And the interesting thing about this is the scale is very small. This is only a few kilometers across. And geologically, to a geologist, to a planetary scientist, this area is incredibly young. There are no impact craters on it. So what is this liquid, perhaps water, most likely water, doing so close to the surface on a part of the planet that's so young, on a planet where we know liquid water is not stable today?

So it kind of drives the physicists a little bit crazy. It really shouldn't be there. It shouldn't be stable so close to the surface. The spacecraft carries a laser altimeter that's determined the topography of Mars better than the topography of the Earth is known, at least to publicly release data. Lots of other information from geology and composition. It's still a very active mission. There's still enough fuel on board to keep doing scientific measurements with Global Surveyor and to also act as a relay for the rovers, for Beagle, and for Mars Express if needed as well.

Go to the next one. And there's a second spacecraft that's there that just got there in 2001 called Mars Odyssey. And Odyssey has a set of experiments that's complementing Mars Global Surveyor. It has a camera that observes in the infrared instead of the visible. It also has a visible camera as well with higher resolution, higher color resolution than Mars Global Surveyor. But its main instrument that it's been using to date has been the gamma ray spectrometer, which produces maps like this.

And this is a global map of Mars with the topography underneath it. And the color is indicating how much hydrogen is on the surface, the element hydrogen. Blue means a lot of hydrogen, and red and yellow means very little. And what this instrument is doing is detecting the amount of hydrogen not just on the very surface but within about the uppermost meter of the surface. So this is saying that at these latitudes near the South Pole as well as near the North Pole, there's a lot of hydrogen in that uppermost meter of the surface.

What's it doing there? Well, you know, hydrogen is a gas, of course. Why would there be hydrogen gas? It doesn't make sense geologically. What makes the most sense is that that hydrogen, that H, is in H2O, ice. is that that hydrogen, that H, is in H2O, ice. What this is saying is even though we don't see evidence for ice in these areas on the surface in camera images, just below the ground, just underneath the surface, there's apparently an enormous amount of water ice, at least on these parts of the planet.

And there's other areas even near the equator that have higher abundances of hydrogen than you would predict. And so this relates to that global surveyor picture I showed of the leaky crater deposits. It's sort of changing people's perspective of what Mars might be like. It's just been assumed. It's just too cold. It's too dry. There isn't any water anywhere near the surface.

It would have all evaporated off or leaked off to space or whatever. But in the face of real data now, which we never had before, people are starting to change that hypothesis a little bit, and maybe there is a lot of water, and maybe it relates to there used to be a lot of water on the surface, and it somehow, a lot of it is now trapped underground as ice. Of course, we've sent landers to a couple of places, right?

The Viking missions in 1976 landed at intentionally incredibly boring places so that they would land safely, and they were not designed to do geology experiments, even though they did make some measurements of geology. They were mostly biology missions. One of them was, they were both the program to scoop up some dirt, mix it in with some chemical soupy organics and see if anything had respiration. And the results are still kind of debated, although generally thought to be pretty negative indicating anything alive on Mars today. But at least one of them survived for something like 2,000 sols on Mars,

and we've got an enormous amount of data on the temperature and the pressure and the climate, the environment that it's like today, as well as some really nice pictures. They were stationary landers. They went to one place. They landed. They had an arm that could reach out. Some of you may have seen it in the Smithsonian, one of the flight spares.

You could reach out and get some samples, but they really couldn't go anywhere besides where they landed. If there had been a dinosaur fossil over here, couldn't get to it. So mobility was really lacking. So sort of in NASA's next attempt to get there was in 97, almost 20 years after the Vikings landed. And it was a very, very different kind of mission. It's called Mars Pathfinder.

Most of you are familiar with it, no doubt. It was different in two ways. First of all, it was a lot cheaper. The Viking was like a $2 billion mission, and Pathfinder was something like 15% of that. The goal was, can NASA get back into the Mars landing business for a lot less than it used to? Good question.

And secondly, the other goal was to give the mission some mobility, more mobility than Viking had. Imagine you're a trained geologist. Somebody says, we're going to some new place. I need you to characterize this landscape for me. Tell me what's there. I'm going to take you there in a helicopter. I'm going to drop you off, and you can't move.

It would be really hard to do. You can look around. You can reach out, but you can't actually move. I mean, the first thing a geologist would do, the astronauts on the moon, the first thing you want to do is get away from where you landed. Go look at the interesting stuff, which is over there, over there. So mobility was really important, and this little rover called Sojourner provided some mobility, and it was a real initial demonstration. Planetary Radio will have more of Jim Bell for you in just a moment, including his description of the Mars Exploration Rovers, which head for the Red Planet in just a few weeks.

Stay with us. This is Buzz Aldrin. When I walked on the moon, I knew it was just the beginning of humankind's great adventure in the solar system. That's why I'm a member of the Planetary Society, the world's largest space interest group. The Planetary Society is helping to explore Mars. We're tracking near-Earth asteroids and comets. We sponsor the search for life on other worlds, and we're building the first-ever solar sail. life on other worlds, and we're building the first ever solar sail.

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Welcome back to Planetary Radio. I'm Matt Kaplan. We're listening to excerpts from James Bell's Mars presentation at Planetary Society headquarters last week. Dr. Bell leads the key imaging team for the Mars Exploration Rovers. Before talking about those probes, he has a bit more to say about the success of the Mars Pathfinder mission, including its aptly named Pathfinder rover. It was a very successful mission in a couple of ways.

First of all, it did demonstrate that NASA could do something like this on the cheap. It did demonstrate many of the technologies required to get mobility on Mars, and you'll see when I talk about our new rover, it uses many of these same technologies, although they're all scaled up. But also, we got science out of it. We got some beautiful images of the sky and the sun for measurements of the atmosphere. The geology of the landing site was investigated,

and there were a couple of pieces of evidence in support of that early wet Mars hypothesis. Parts of the landing site and some of the clues in the minerals that are inferred to be in the rocks are consistent with this area having once been flooded. Not a unique interpretation, and there's still a lot of argument at meetings about exactly what all the data means, but at least it was an attempt to test the hypothesis in that direction.

And what comes next is this. It's called the Mars Exploration Rover Mission. The mission is to launch two rovers next month and land them both in January. They do take advantage of the Earth and Mars are very close together this year. If you time it just right, you can launch a rocket from the Earth for the lowest amount of energy. When you time it just right this year, the lowest amount of energy is also a very short path. It takes only seven months to get to Mars, which is a very short amount of time for planetary missions. The history of this mission, this actually

goes back, I've been working on this about seven years, the team and I have been doing this. It's led by a guy named Steve Squires that maybe some of you know at Cornell. We responded to a proposal seven years ago that NASA put out to put instruments on this kind of a rover. And it was variously canceled and then resurrected. Some of you know it was resurrected as a lander for a while in 2001. That was then canceled. Then it got reinstated. 2001, that was then canceled.

Then it got reinstated, and then after it got reinstated in 2000, NASA came and asked Steve, would you guys like to do two? And, you know, we thought about that for like a nanosecond. Yeah, of course we'd like to do two. I mean, come on. It turns out you can send two to Mars for much less than twice the price this year because it's such a favorable opportunity. And also, if you think about it, it's the way NASA used to do things as well, two of everything, the Vikings, the Voyagers, the early Mariners, right?

It's a way to decrease risk. You don't see much data from Mariner 8, right, because it's sitting in the ocean off of Cuba. They used to do things in pairs, and so did the Russians, for that matter, because it's intrinsically risky. And the success rate for Mars missions is less than 50% if you count them all up. So it's just a hard thing to do. You can test and you can build great things and have great people, but boom. Sometimes bad things happen.

We saw that in 1999. The Polar Lander and the microprobes failed because of technical problems, and the Mars Climate Orbiter failed because people weren't talking to each other the right way, and it got driven into the atmosphere. And these things happen. So part of it, part of the reason for sending two is pragmatic in that it's cheaper than it ever will be to send two, and also part of it is to try to reduce risk and acknowledge that it's intrinsically risky.

The difference besides just size is range. This rover could conceivably travel 100 meters a day if we wanted it to, a football field a day. That little Sojourner rover traveled 100 meters over the course of about 83 days on Mars. Whether we will ever travel 100 meters a day, I don't know, because that would require a gung-ho bunch of Mars geeks basically putting blinders on and driving past all this really cool stuff to get to 100 meters away. That's going to be a discipline issue on our part, right? Nonetheless, the equipment has that capability,

and that's a good thing because we want mobility. We know we're probably not going to land exactly where the most interesting thing is within a kilometer or so. It has a lifetime of 90 days on Mars, manufacturer's warranty. What does that mean? I don't know. It's a really risky thing. Just for reference, the warranty time on the Sojourner rover was one week,

and it was still working after 83 days. The warranty time on the lander that went with that rover, the Pathfinder lander, was one month, and it lasted 83 days. So nobody really knows how long the Sojourner rover lasted. It could still be working. We don't know. We can't communicate with it directly. And for scale, it's about the size and weight of a golf cart,

and it carries five science instruments which are called the Athena payload, and this is what Squires and a bunch of us proposed originally back in 97. We were competing with five or six other groups to put payload on this rover, and our proposal was select. Just a few words about some of the different instruments. That mast, which has got the cameras on top of it, lies down to start, and then it's deployed up. And when it's deployed and when this camera bar is flipped up,

it's about as high as a 10-year-old's eye. So that's the little mnemonic. Bill Nye taught me that one, a little mnemonic. About as high as a 10-year-old's eye. So that's the little mnemonic. Bill Nye taught me that one, little mnemonic. About as high as a 10-year-old's eye. Tell Bill I'm using it. So it's a pretty good perspective. You know, it's the sojourner, to understand the sojourner data,

to look at the pictures from that rover, you have to lay down on your stomach and imagine yourself as a tiny little person. And when you see these boulders in this image from these rovers, you see these giant rocks, they're really only little tiny things that would fit in your hand. Here we'll at least get a perspective of being up a little bit, looking around, and seeing off well off to the horizon. There are four cameras up there. You can see it here. Two of them are

a kind of camera called PanCam for panoramic camera. It's called panoramic because that mass can spin around, all the way around, and it can point up and down. So we'll take these mosaic panoramas with the instrument. And PanCam is special because it's the only camera, two cameras on the rover out of the nine of them, that can take color pictures. So it has a little filter wheel inside this little housing

with a little motor. And so you point at something, you rotate the filter wheel to red, you take a red picture, you rotate to green at something, you rotate the filter wheel to red, you take a red picture, you rotate to green, you take a green picture, rotate to blue, take a blue picture, send all the pictures back. Someone like me sits down in Photoshop or something and puts them together and makes a color picture. And that's basically how it's done. So to take a color picture, we send three images back.

Half a planet away, there's another rover that will land there on January 25th and do the same kind of thing at a very different landing site. So if we're very lucky, if we're very successful, we'll have two rovers operating on the surface for three months or more very early next year. So, wish us luck. We're going to need it. That was Dr. Jim Bell of Cornell University. He leads the PanCam team that hopes to soon give us our best view ever of the Martian surface. I'll be back with Bruce Bet, back with Q&A.

Why aren't we looking for life in moon rocks as hard as we're looking for life in Mars rocks? The interest in organic compounds and life on Mars is heightened by evidence for liquid water there. There is no evidence for liquid water on the Moon at any time, ever. The only hydrogen on the Moon comes from the solar wind or asteroids and comets. There may be water frozen in the cold traps at the lunar poles, but definitive evidence of even that has not been found. Analytical techniques have improved significantly since the Apollo samples were studied, so smaller amounts of organic materials might be detectable now. However, the biological nature of any of these compounds in lunar materials would be very difficult to prove because of the clearly non-biological origin of most of the moon's carbon.

Got a question about the universe? Send it to us at planetaryradio at planetary.org. Be sure to provide your name and how to pronounce it and tell us where you're from. And now, here's Matt with more Planetary Radio. So glad to be in person with Bruce Betts for this week's segment of What's Up. Bruce, welcome back.

Thank you very much. I'm totally excited to be here. Well, let's get started. What's up this week? All right, we've got our standard planets. Let's whip through those. We've got Jupiter, very bright in the evening, brightest thing in the sky. Saturn, also visible in the morning. Venus, extremely bright in the morning sky in the east. And Mars, about 60 degrees to the right of Venus, looking orangish-reddish. But the really exciting thing we've got this week is a total lunar eclipse. The moon will be entering the Earth's shadow and will be visible to a lot of the people on the Earth. It will be visible from the Americas and from Europe and Africa.

It will not be visible from Asia, Australia, and various oceans. But that's going to be on May 15th, Thursday, May 15th. So set your calendars. The totality, the total eclipse portion, begins at 8.14 p.m. Pacific Daylight Time, and the totality ends at 9.06 p.m. Pacific Time. There will also be partial eclipse for about an hour before and after those times of totality. And you can see the moon, depending on where you are, it will be off roughly in the southeast, slight variations depending on where you are. Now, selfishly, will we see a total eclipse from Southern California? Yes, we will, but the moon will rise in partial eclipse in California, in Western North America,

but then we will see the total eclipse, including the deepest portions. In fact, all of the U.S. will except for Alaska, and then Hawaii will just see it already well into eclipse. Excellent. What a convenient time to be out there, at least for those of us on the west coast of the U.S., 8-14. Let's move on to this week in space history. First, I have to ask, did you think that was totally cool or only partially? I'm sorry. Eclipses are always totally cool.

Okay. Thank you very much. This week in space history, on May 14, 1973, Skylab, the U.S. space station, was launched. Now, that was totally cool. Oh, that was. That was bad station, was launched. Now, that was totally cool. Oh, that was. That was indeed. 30 years ago. 30 years ago, we had a functioning space station.

Many people forget this in orbit. Much smaller than the current one being assembled there, but still had people up there. I believe three different crews. You're spending about three months each. Got some good work done, too. Now we can go on to... Okay. Random space fact!

During a lunar eclipse, such as, for example, the one this week, one can view the curved shape of the Earth's shadow, which is naked-eye, ground-based evidence that the Earth is indeed round. Now, the first thing that occurred to me, me being me, of course, is that the geniuses, the Mensa members at the Flat Earth Society, have surely come up with a logical explanation for why the flat Earth would form this curved shadow on another body. I have no doubt that they have done that,

but we'll not go into it in depth here because my small brain is not able to comprehend it. You know, I used to think they were so cool because I thought, they don't really believe that? They're just tweaking us and what a great thing for them to do. Ladies and gentlemen, they really believe it.

So anyway. So you can see the flat moon from the flat earth in eclipse. Can they sue us? We better move on before it occurs to them. No, I don't think so, but they can enter our trivia contest. Last week's trivia question, the Earth passes through two meteor showers each year that are generated by Halley's Comet. This is the Halley's Comet crud, as we called it last week.

One is the Eta Aquarid meteor shower, which happened just this last week. What is the name of the other one? How'd we do on answers? Ah, we had 20 correct answers, which is pretty darn good. And the winner was Henry Sanford Crane. Henry Sanford Crane of Elkton, Maryland. And Henry, you may or may not be receiving a T-shirt. You will be receiving a gift. It's nothing personal. You'll definitely get something swell, wonderful from the wonderful merchandise warehouse here at the Planetary Society.

We're moving on to the exciting Mars in 3D posters. See Mars from Mars Pathfinder in 3D. Now, did we say what the correct answer is? No, we didn't. We're letting people ponder it. It adds an air of suspense. But the correct answer, perhaps pronounced incorrectly, is the Orionids. And that would be, they are called that because... Because the meteors, if you trace the streaks of the meteors

back in space, they all appear to radiate from the constellation Orion. We have a minute left to get the new trivia question out to everybody and tell them how to enter. All right. As we heard recently, one of the two selected landing sites for the Mars exploration rovers is Gusev Crater on Mars. Who was Gusev? And what did he feel about, no, who was Gusev? We'll leave it at that. Things like what was his profession? Where is he from?

And that will be sufficient to win yourself a Mars in 3D poster. However, not of Gusev Crater. Remember that the deadline for entering is Thursday at noon. Thursday at noon so that we can go through, decide who was correct and who wasn't, and randomly

from all of the correct answers, pick out the winner. And you know what we need to say? There are so many faithful people who are entering every week, every week, and do not win. And it's not because we don't like your name or where you live or anything. It's truly random, folks.

We can only thank you for all the great work, and keep listening. Yes, thanks to all of you, and the rest of you who want to enter and join this esteemed group, go to planetary.org and follow the links to Planetary Radio. Bruce, happy eclipse. Thank you very much. Look up in the night sky and think about whether the Earth is flat.

Thank you, and good night. Bruce Betts is the Director of Projects for the Planetary Society. He joins us each week with this segment we call What's Up. Our time is up. Join us again next week for another edition of Planetary Radio. Thanks very much for listening.