Planetary Radio: Space Exploration, Astronomy and Science - A New Dawn for Interplanetary Exploration

Episode Date: July 2, 2007

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The dawn of a new age of interplanetary exploration, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier, and this week into the asteroid belt. I'm Matt Kaplan. By the time some of you hear this, the Dawn Discovery Mission may be on its way to Vesta and Ceres, the two largest denizens of that ring of flotsam and jetsam between Mars and Jupiter. It really is a revolutionary mission in many ways, as we'll hear from Mark Raymond, Dawn's project system engineer.

Emily Laktawalla takes us back to the biggest volcano in the solar system for this week's Q&A segment. Is it just a long-dead monument, or could mighty Mount Olympus be ticking down to another eruption? And we'll finish with a look at the night sky from Bruce Betts, along with a random space fact that may make you think twice about living on the moon or a space station. The top news story in this corner of the Milky Way also takes us to the red planet. Mars Exploration Rover Opportunity has begun what may be its most

perilous adventure since it bounced down more than three years ago. The little explorer has begun its descent into Victoria Crater, where tantalizing rocky outcrops ago. The little explorer has begun its descent into Victoria Crater, where tantalizing rocky outcrops await. The complete story, including an update from Spirit on the other side of Mars, is at Planetary.org. Nighty-night, New Horizons. The Pluto probe has gone to slumberland. It will spend much of the next eight years in hibernation. Actually, this first snooze is more of a nap. The spacecraft will wake up in just two weeks to do some housekeeping. Emily has the details in her blog, also at planetary.org. That's also where she'll show you the latest images from Cassini in the Saturnian system. The Senate Appropriations

Committee voted to increase NASA's budget beyond the figure requested by the Bush administration. It's a big step, but the full Senate still has to weigh in, so don't go counting moon missions just yet. Emily is up next. I'll be right back with Mark Raymond to talk about the arrival of dawn. Dawn. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, when was Olympus Mons erupting? Olympus Mons on Mars is the solar system's largest volcano. It's about three times taller than Earth's tallest volcano, Mauna Kea,

but it's no dramatic peak. It's actually quite broad and flat. An astronaut standing on its flank would be unable to see the top until she had walked right up to it. However, from the edge of the peak rim, she could look down across a summit caldera 80 kilometers wide. A caldera is a steep-sided pit that forms when a volcano's magma chamber blows out and the former surface of the volcano collapses. The caldera of Olympus Mons records many such eruption and collapse events.

Scientists have examined images from the Mars Express spacecraft, counting craters on the different collapse areas, and have figured out that Olympus Mons was active as early as a billion years ago and as recently as a few million years ago. A few million years is long to a human, but in geologic terms, it may as well be right now. Does that mean that Olympus Mons may still be active? Stay tuned to Planetary Radio to find out. No doubt about it, Dawn is pushing the envelope.

It has the biggest solar wings ever installed on an interplanetary probe. And it needs every one of the 10,000 watts that will be generated, not just for its electronics, but for the big ion engine that will push it out to asteroid Vesta. After orbiting Vesta for some months, that engine will fire up once again for a long trip to the biggest object in the asteroid belt, dwarf planet Ceres. It's Mark Raymond's job to make sure everything comes together for this eight-year mission. We found Don's project system engineer at his Jet Propulsion Laboratory office just before one last visit to the Kennedy Space Center before a possible July 7 launch. Mark, thank you for joining us on Planetary Radio. Where do we stand as this mission looks forward to, as we speak, a launch window

that is just a few days away? We're getting very close to launch. Everything's coming together, but it is a very tight opportunity because we've already had some launch vehicle delays, and so we're being pushed up against the end of our opportunity to launch because in addition to the Dawn mission, NASA's getting ready for a very exciting mission to Mars called Phoenix. They need to launch in August. And so we're getting squeezed a little bit. But things right now look fine for July 7th. And as it turns out, if we're unable to launch in July, we have a

terrific opportunity to launch in September or October and do just a wonderful science mission in either case. Now, it's actually quite fascinating that Phoenix has no choice. It must get out of here and leave this planet in August. But it's part of the wonder of this spacecraft that you have much more flexibility. That's right, we do. And the reason is because we use ion propulsion. Now, the first time I ever heard of ion propulsion actually was in a Star Trek episode, but there's a real technology behind it.

It's not just science fiction. And the fantastic capability of the ion propulsion system gives us much, much more flexibility than normal planetary missions have. So we don't have to launch in a very narrow period of time like most missions do because the ion propulsion system is so effective once we've gotten into space. So Don has the ability to live long and prosper thanks to this technology. One might say, since I know that you are, just from reading your journals that we'll get into, that you have to be something of a science fiction fan.

I certainly am, and I'll tell you, one of the great rewards of working on a project like this is getting to turn the science fiction into science fact. And then, of course, the science fiction writers come back and turn what you learn back into stories, back into fiction. But that's a topic for another day. Okay. It is also part of this spacecraft's amazing capabilities that you've got two destinations, and you're going to linger at each one.

That's right. This is going to be the first mission that's ever planned to go into orbit around a distant solar system body and then leave orbit and go to another body and go into orbit around that. In some sense, it's almost like it's the first true interplanetary spaceship, because no spacecraft has ever had this capability before, and it's thanks to the ion propulsion. I'd love to think that this is a preview of other kinds of missions with these capabilities, like the one that has been talked about for years, for the Jovian moons, where we could really take a close look at Europa and then move over, maybe move in closer and look at Io?

Yeah, I think that there are a lot of possibilities with ion propulsion, and we're only starting to take advantage of them. But really, this is an example of just the overall progress of humankind's ability to explore the cosmos. If you think about any of the missions that we're doing now and what people foresaw for the future decades ago, in many cases we're way beyond what people expected we'd be able to be doing. We mentioned at the outset that your title is Project System Engineer. What does that actually mean? What are your duties? Well, I get to be involved in all technical aspects of the project. That is the spacecraft design, the instrument designs, the design of the mission and the formulation of the trajectory,

the plan for what we're going to do while we're in flight, as well as the development of tools and systems and procedures on the ground for how we're actually going to operate it, and then try to pull all those pieces together to make sure they integrate smoothly and everything works. And so it's really very rewarding and exciting for me because I get to see all different aspects of the project, and I think that's a lot of fun. So the stress is on the word system. That's exactly right. Pulling everything together, making one overall system that in the end is going to return this fantastic science from Vesta and Ceres. Talk about the science that this spacecraft is capable of.

You've got, what, a couple of spectrometers and a camera? Well, we have two cameras which see from the visible into the infrared, and so they'll produce color pictures. And we're going to use them to take stereo pictures, so we'll actually be able to develop a three-dimensional view of these bodies, topographical maps. Wow, get out the 3D glasses. Exactly. We also have a mapping spectrometer that works from the infrared through the visible down into the ultraviolet.

That'll help us determine what minerals are on the surface of the visible down into the ultraviolet. That'll help us determine what minerals are on the surface of the bodies. We also have a gamma ray and neutron detector, which detects these high energy photons. Even if you go from visible light to ultraviolet, then on to x-ray, then the next energy level is gamma ray. So that will help us determine what elements are made on the surface, that is, what the atoms are. That will also help reveal, if it's there, the presence of water, and that's of particular interest at Ceres. And finally, we have a system that will allow us to very, very accurately measure the gravity field, and that will tell us something about the internal structure of these bodies. You know, when I first read about that, I was mistaken and thought that it was a radar system,

but it's really just an extremely sensitive communication device. That's exactly right. We measure the Doppler shift of the spacecraft in much the same way that Doppler shift is used for all kinds of measurements here on Earth. And, of course, people are familiar with the Doppler shift from just listening to, for example, a siren going by as its pitch changes. But exquisitely accurate measurements of that allow us to determine how hard Vesta or Ceres is pulling on the spacecraft as it orbits. And that, combined with other measurements,

allow us to determine more than just the mass of those bodies, but actually how that mass is distributed. And so you can determine whether there's a very dense core, for example, surrounded by less dense material or some other internal distribution of matter. And that's very important for understanding the overall structure of these bodies and how they fit into the formation and evolution of the solar system. That's Mark Raymond, project system engineer for the Dawn mission. We'll hear more from Mark when Planetary Radio returns. 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

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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. The Dawn mission targets Vesta and Ceres, the two biggest objects in the faraway asteroid belt.

We're talking with Mark Raymond, project system engineer, for this revolutionary mission. Let's continue the discussion of the science that the spacecraft will be able to do. And really, it's these target bodies. You already said that Ceres may be a place to look for water or at least water ice, but probably not on Vesta, at least from what I've read. These are very different worlds. They are, and that's the reason we're so interested in going to visit the two of them.

This is really a mission of comparative planetology. And again, because we can orbit both of them, it's a kind of mission which humankind has not been able to undertake before. Vesta and Ceres are at nearly the same distance from the Sun. Not quite. Vesta's a little bit closer, but not a lot. So the question is, why are they so different when presumably they formed in just about the same locations? Vesta is a rocky body, and telescopic observations show that it's covered with a material that looks very much like basalt, or the evidence of it having melted at some point and been covered with lava.

Ceres, just a little farther from the sun, has evidence of containing a vast amount of, as you said, water ice, or perhaps even liquid water. amount of, as you said, water ice or perhaps even liquid water. So Vesta is somehow representative of the inner bodies of the solar system, the rocky bodies, one of which is under our feet right now, as well as Mercury, Venus, the Moon, and Mars. And Ceres seems to be more typical of the icy moons of the outer solar system, the moons of Jupiter and Saturn. It's almost as if these two bodies span a sort of dividing line in the solar system, and some astronomers refer to it as a dew line. Water, ice, outside that line, rock inside. And so comparing them should be very revealing about the structure of the solar system and why it's organized the way it is.

Well, it occurs to me that since a mission to take a detailed look at, oh, an outer planet moon like Europa is probably still a long ways away, if indeed you discover that Ceres is an icy body with a liquid ocean underneath that ice, icy body with a liquid ocean underneath that ice. This is a tremendous opportunity to study that kind of body, which has intrigued scientists so greatly over the last few years. I think that's exactly right. And again, that's part of the reason this is so exciting. And Ceres has even more to offer than just that. You know, it's the largest asteroid.

In fact, it's now classified as a dwarf planet. And so this is really a kind of body that we have not yet studied in detail. And I think there's still plenty to learn from missions like this. There were just some images taken, snapped by the Hubble Space Telescope. From what I've read, they're the best pictures we've ever gotten from Earth-based instruments, if you can call Hubble Earth-based. Right. But nothing, of course, compared to what you'll be able to pick up in fairly low orbit.

That's right. Of course, Earth is several astronomical units, so a few hundred million miles, roughly half a billion kilometers from Vesta and Ceres on average. And Dawn will get down to very low orbits and very close. At Vesta, the lowest orbit will be at an altitude of less than 200 kilometers or a little bit more than 120 miles. That's really close. That's closer to Vesta than the space shuttle

and the most low-Earth orbiting satellites are to Earth. And we know what kind of spectacular views you can get from that sort of vantage point. And at Ceres, we won't get quite that close, but our final orbit will be about 700 kilometers in altitude or a little over 400 miles. And so we're really going to be able to get spectacular views of these now distant and alien worlds. But we're going to have to wait a little while for those views, because I think it's going to be, what, about four years before you reach the first? That's right. We launch, of course, this summer, 2007,

and Dawn will arrive at Vesta in the second half of 2011. So it's a long journey, but once we're there, I think the rewards will more than make up for it. We'll spend, oh, about seven or eight months in orbit around Vesta, and then we'll leave. And then it's another nearly three years' travel to go around the asteroid belt to Ceres, and we'll arrive at Ceres in February of 2015. How long have you been involved with this project? private series in February of 2015. How long have you been involved with this project? I started in the autumn of 2002, so going on five years now.

Like all of these missions, there is a large team. I was looking at all the faces that are on the website. We will, as always, provide a link to the Dawn mission website from planetary.org, where some people may be listening to this radio program. And we've got excellent coverage of the mission on our website as planetary.org, where some people may be listening to this radio program. And we've got excellent coverage of the mission on our website as well. You know, and I should mention here that your Dawn journals that you're preparing for the mission website are also now appearing on the blog of my colleague, Emily Laktawalla. People can check those out as you add more entries. And by the way, those are great fun.

Thanks. I appreciate that. I hope people do check it out. And I've taken a look at the coverage for Dawn and other missions at your website, and it's impressive. I hope people visit. Well, thank you. We'll pass that along. But you've got a lot of stuff going on on your website as well, in addition to your Dawn Journal. I noticed that there is a newsletter called the Dawn's Early Light Newsletter from the science team. Obviously, they have a sense of humor, too. Right, and people can receive that newsletter for free by signing up at the website. Excellent. So they can get that as, what, an RSS feed, or it's just mailed out to them? I think it's just emailed out. Yeah. We're almost out of

time. Is there anything else about this mission that you'd want to share with people, or just leave us with something to look forward to? Well, I think there's a lot to look forward to, but I'd come back to just reminding people of how exciting it is to be exploring new worlds. In my view, Vesta and Ceres truly are among the last unexplored worlds of the inner solar system. I think most people think of asteroids as little flakes of rock, but these are big places. They're truly worlds. So I hope people will follow along because I think it's really going to be exciting as

we unveil them. And if you want, I mean, since you are on the radio right now, you could apologize to all those alien civilizations you mentioned in your journal who are following the mission, and particularly the, was it the 350,000th Event Horizon Games in the Virgo Cluster of Galaxies, where I guess your launch window opens up right in the middle of those games. Well, that's right. So some of our fans are going to have a difficult choice to make over whether they want to follow those games or the mission. But I think ultimately the mission would be the better choice.

All in good fun. Prior to the launch of a very exciting and unique and unprecedented mission, Mark, thank you so much for spending a few minutes with us here. And I hope that we can check back with you once you are on your way and that ion engine has been fired up and you're headed off to Vesta. Well, thanks very much. I appreciate your interest, and I'd be happy to come back and tell you how we're doing and what we've got to look forward to. Thank you. Mark Raymond is the project system engineer for the Dawn mission. He is speaking to us, was speaking to us, from his office at JPL,

for the Dawn mission. He is speaking to us, was speaking to us from his office at JPL. And we will be following that mission both at planetary.org and right here on Planetary Radio. We're going to move on to another look at the night sky. That'll be What's Up with Bruce Betts right after this return visit from Emily.

I'm Emily Lakdawalla, back with Q&A. Scientists have determined that the solar system's largest volcano, Olympus Mons, was active as recently as a couple of million years ago. Does that mean it could still be active? In fact, yes, it seems quite possible that Olympus Mons may have more eruptions in its future. But don't get too excited about the possibility of witnessing rivers of lava flowing across the Martian ground. Evidence suggests that periods of dramatic eruptions and volcanic activity on Olympus Mons are followed by long periods of quiet. If Olympus Mons were to erupt again,

it would probably happen sometime in the next 10 million years or so. That could be tomorrow, but it's statistically unlikely. It's much more likely that the next eruption will happen long after there are no longer any human observers around to see it. Got a question about the universe? Send it to us at planetaryradio

at planetary.org. And now here's Matt with more Planetary Radio. It's a pre-holiday what's up. We are on the phone with Dr bruce betts the director of projects for the planetary society and uh bruce a happy pre-4th of july as we record this anyway some people will be hearing it after the festivities and uh welcome thank you very much so listen it was only yesterday as we record this that i went out there and i pointed to every one that I saw. Look at that. Look how close they are. Well, good for you. You should have since I've been harping on it. Venus and Saturn close together in the night sky. They're going to start to separate some, but they're still pretty close. If you go out after sunset and look over in the west, the really bright thing is Venus,

and the less bright star-like object is Saturn nearby. They're both going to start slipping down below the horizon. So if you want to catch them in the evening sky, you should be doing it around now. You know what was really useful to me? Because I've always thought of Saturn as very bright. But when you see the two of them next to each other, now, of course, I guess you've said Venus is especially bright right now, but, man, what a difference. Venus was all over Saturn.

It's the brightest star-like object in the sky. Oh, I've heard that. Besides, you know, the sun. Yeah. We've also got another bright star-like object on the other side of the sky right now. In the early evening, you can see Jupiter, also quite outshined by Venus, but highly outshining Saturn. And Jupiter, you can find, is the brightest star-like object over in the east after sunset, moving over towards the west. And then in the pre-dawn or middle of the night, you can start picking up Mars in the fairly high up in the east.

Pretty dim, a little dimmer than Saturn right now, and is reddish, and you can, if you have trouble finding it, and you're up in the middle of the night or pre-dawn, on July 9th, it is very close to the moon. It's the reddish star-like object near the moon. So that's where your planets are these days. Now we'll move on to random space facts. This is an interesting one, I thought, Matt. Did you know that I have it on good authority that humans, assuming they're consuming regular food and liquids, they're actually a net source of water?

What does that mean? I don't understand. Conservation of matter. You only get out what you put in, right? Well, no, but they're taking and converting some of the moisture in the food into a liquid, let's say. So where this comes up, you may ask, why, pray tell, Bruce, did you bring this up? I'm not sure I want to know. Well, you don't, but I'm going to tell you anyway.

Well, you don't, but I'm going to tell you anyway. As you ponder things like space stations or someday humans on the moon or on Mars. Oh, I was afraid you were going in this direction. Ick. You only actually have to recycle about 70% of the water in a human base to satisfy the freshwater needs of a base. You know, if you're not doing agriculture or something like that. I thought you'd like that. Shall we move on?

Yeah. On to the trivia question. We asked you, well, we stated, as people know, there are about 365 and a quarter solar days in an Earth year. How many sidereal days are there? Shall I discuss what a sidereal day is now, or do you want to talk about how people did? Yeah, please go ahead and explain it, because I don't think it's what we got from Donald Belew, who said that, is that the place where the Soviets used to send people they didn't like? No, no, I don't think so.

That was the Gulag Day, which was really long. That's right. But a sidereal day, first of all, a solar day is what we usually talk of as a day, and it's how long it takes the Earth to rotate around so the sun is in the same spot in the sky. But also, remember, the Earth is moving around the Sun at the same time. So a sidereal day is how long does it take to actually have the Earth rotate 360 degrees relative to, like, the stars, the fixed stars off at a distance. And that's a little different because of the motion. The sidereal day is slightly shorter than a solar day.

So that leads us to our answer at about 366 and a quarter, adding one day, that's how many sidereal days there are because of an extra rotation of the Earth as it's going around the Sun. And what do we do with those answers there, Matt? That is exactly the answer that William White came up with. In fact, to be more precise, 366.242199 of those sidereal days. And so, William, Bruce says you're right. They're in West Lafayette, Indiana, and that's where we're going to send a Planetary Radio t-shirt.

Congratulations. And if you'd like to win your very own Planetary Radio t-shirt, answer the following question. What was the fourth spacecraft? I'll have you know that was a randomly selected number. The fourth spacecraft to orbit the Earth. Not with humans, just the fourth spacecraft to orbit the Earth. We can all say, hey, Sputnik was the first one, and Explorer 1 was the first American one, but where in the sequence was the fourth spacecraft to orbit the Earth?

Go to Planetary Radio. Sorry. You know that place. Go to planetary.org slash radio and find out how to send us your entry. And when do they need to get those in by, Matt? July 9 at 2 p.m., to be more precise. Monday, July 9. And we'd love to get your entry in the contest.

That would be good. In the meantime, I'm looking forward to next week, seeing how we do with the somewhat more qualitative Planetary Society logo space shuttle patch question. Yeah, getting lots of interesting answers, and they do seem to be zeroing in on one particular answer. So stay tuned. I was worried, so I'm glad that's happening. Yeah, a little bit of open to interpretation there, but it's all averaging out's all averaging out we were reaching a mean here wow well that's a mean comment are we uh we about done here i think we are all right everybody go out there look up in the night sky

and think about lint giant balls of lint thank you good night you know what i hate really about lint it's not so much the lint it's how Sears dryers put the filter on the top, and so you can't clean the things without getting the lint all over the dryer. There's someone laughing in the Sears engineering department. Yeah, laughing or crying, I guess. All right, well, in case we hear from Mr. Sears or Mr. Roebuck real soon, we'll just let you know that that's Bruce Betts, the director of projects at the Planetary Society,

who joins us each week until we get sued right here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week, everyone. Thank you.