Planetary Radio: Space Exploration, Astronomy and Science - Dawn is Setting Records On Its Way to Vesta

Episode Date: June 21, 2010

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Ion Engine Speed Dawn Toward Asteroid Vesta, this week on Planetary Radio. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Dawn Mission Chief Engineer Mark Raymond returns with an update on the spacecraft that will orbit the two largest asteroids in our solar system. Emily Lakdawalla reports on another impending encounter with a big space rock in the Planetary Society blog. And Bill Nye, the planetary guy, will salute the now fully deployed Icarus solar sail. Have you ever wanted to have your very own space shuttle? Bruce Betts and I will help you get it if you tell us why you need one.

That's later during What's Up. First up is Emily. She took time out from her vacation to join me by phone for a review of recent blog entries. One of the most significant things that you covered over the last week was this upcoming encounter between the European Space Agency's Rosetta and Lutetia. Yes, Rosetta is, I think, the spacecraft that must win the award for the longest and most circuitous cruise to its eventual destination. It arrives at Khamaturyumov-Gerasimenko in 2014. On the way, it's encountered Earth a couple times in an asteroid named Staints, and this time it's about to fly past an asteroid named Lutetia.

Lutetia is by far the largest asteroid that has ever been visited by a spacecraft. It's numbered 21 in the asteroid catalog, and that alone tells you that it was discovered pretty early on, so it must be pretty big. And for that reason alone, I'm pretty excited about seeing it. They've planned the flyby so that the asteroid should pretty much fill the field of view of the cameras at closest approach, and they've just sighted it for the first time in their navigational cameras, and those pictures will just slowly grow in size until Encounter Day on July 10th. There is a nice image on the blog, and we'll link to this entry,

showing really a whole family of asteroids and comets that have been visited so far. Yes, and you can sort of imagine Letitia pretty much covering up the entire diagram. You'd have to pack them a little closer together than they are in my picture, but that's how big Letitia is, so I'll need to make a whole new scale diagram once we've flown past this one. Moving on and looking a little further back into last week, there is a pretty amazing image from Icarus, now fully deployed. Yeah, the Japanese were, as usual, very smart, and they put something on the spacecraft. As far as I know, I don't think it's been done on a deep spacecraft before.

They had these two little tiny deployable cameras. They're little cylinder-shaped things, about five centimeters long. And once they finished deploying the sail, they popped one of them out, and it popped it out with a little bit of a spin, so it spin-stabilized. As it receded, it shot numerous photos of the sail, so we got to actually see the spacecraft floating in space, which is really awesome. That was actually only the first act. The second one, I think, as we speak, has been deployed,

but they've not yet released any images yet. So that's something to look for on the JAXA website. You also talk on the blog about the long hours that you put in sort of monitoring both Hayabusa and Icarus. But you found an interesting way to pass the time. That's right. Well, you know, the hours working on covering Japanese missions are just bizarre because it happens kind of late in my evening. And so just a while away at a time between events and the Hayabusa return, I had discovered recently a Japanese craft called amigurumi. They're little tiny crocheted

anthropomorphized animals or whatever. And so I decided to make myself a little amigurumi Hayabusa. And it's been declared kawaii by a great many Japanese, which means cute. And to Japanese, it's high praise. I was going to say very high praise. Beats Hello Kitty in my book. Emily, thanks a lot. Enjoy your vacation, but we'll talk to you again next week. You're welcome, Matt. Emily Laktawala is the Science and Technology Coordinator for the Planetary Society and a contributing editor to Sky and Telescope magazine.

I'll be back in a couple of minutes with Mark Raymond and a Dawn mission update. That'll be right after we hear from Bill. Hey, hey, Bill Nye, the planetary guy here, executive director, designate of the Planetary Society. And this week, the big exciting news is international. It's from JAXA, the Japanese Aerospace Exploration Agency, they have the ICARUS. This is an English acronym from a Japanese space agency. It stands for Interplanetary Kitecraft Accelerated by Radiation of the Sun. It's a solar sail. And they deployed it on the way to Venus.

The Akatsuki spacecraft is going to go to Venus and look around. spooky spacecraft is going to go to Venus and look around. But in the meantime, with this elegant spiraling out from the center spokes of a wheel spacecraft, it deployed this big, very, very thin solar sail in the hopes that it will be pushed by the photonic pressure of sunlight, the momentum of photons. It took them a couple days. They didn't want to get tangled up. But it worked. This could be the future of space exploration. Way to go, JAXA. Way to fly, Bill Nye the Planetary Guy. I could begin our review of the Dawn mission by reintroducing you to Mark Raymond, but why would you want to hear me do this when you can have William Shatner? Now, Mark Raymond doesn't just spend all his time sneaking off to do Scotty impressions during his lunch break. You see, he's actually been rather

busy, well, being Scotty. Next year, he's sending his latest creation called Dawn 300 million miles across the galaxy to say hello to an unexplored asteroid belt, just a meteor shower on the other side of Jupiter. I've been there. Actually, it's lovely at this time of year. The Shat pretty much got it right, though that show was made in 2007. We'll point out that the Dawn mission to the largest asteroids in the solar system is not entirely Mark Raymond's, but Mark is the chief engineer at the Jet Propulsion Lab for this unprecedented attempt to orbit two very hard-to-reach bodies. Mark recently joined me on the phone from his JPL office.

Mark, it's great to have you back on Planetary Radio, and frankly, I'm surprised, though pleased, that you didn't just turn me down flat this week. Because of this small task you have underway, would you tell people about what's going on right now? Sure. Well, first of all, I appreciate your having me back, and I appreciate your interest. We just are in the final stages of loading new software into the primary flight computer on the Dawn spacecraft, which is right now in the asteroid belt between Mars and Jupiter. And if you've ever tried installing software on your home computer, you know it's not always the easiest thing to do,

but it has gone absolutely perfectly. We're not finished with all of the steps yet, but everything's going just beautifully, and so I'm able to take the time to spend with you and your listeners. Maybe I could get you to help me upgrade to Windows 7. That's probably beyond our capabilities. Well, congratulations in progress, at least so far, because that's got you and others there have to be anxious when something like this is taking place so far from home.

Well, there's some anxiety, but of course we spend a lot of time preparing. We test all of the procedures in our spacecraft simulator here at JPL. We have done this before. This is the third time that we've replaced the software on Dawn since we launched in 2007. And while it's never something to be taken lightly, we don't enter into it unless we feel pretty confident that we know what we're doing and what all the steps need to be. Best of luck for successful completion of that. Something else that has already happened

came from your media relations folk who talked about a record that your spacecraft just set a few days ago. That's right. It was about June 5th or so. The spacecraft had accomplished so much thrusting with its ion propulsion system that it had changed its velocity by more than any other spacecraft. This is important because we need a lot of thrusting with this advanced technology to get the spacecraft out to the asteroid belt and into orbit around its destinations. And this is just an illustration of the progress we're making. held by another spacecraft that both of these were held by another spacecraft that you had a lot to do with,

which I guess will be the record for continuous powered spaceflight? That's right. Well, first of all, the previous spacecraft that you're referring to is Deep Space One, which was the first interplanetary mission to use ion propulsion. I was lucky enough to work on it. And one of its primary purposes was to test ion propulsion and other advanced technologies so that subsequent, more ambitious missions could rely on them. And so Dawn is one of the beneficiaries of that project. The other record that you're referring to is the total number of days of powered flight is, thrusting with the ion propulsion system. Now, I should say that Hayabusa, which just returned to Earth, also has accumulated a

tremendous amount of time thrusting with its ion propulsion system. And I'm actually not sure right now how much total time it accumulated. I know in terms of the number of hours for each of the thrusters, it's certainly extraordinarily high. It also is really pushing this technology to take advantage of what it can do for our efforts to explore the solar system. And after all, this isn't really about setting records, is it? No, it certainly isn't. Yeah, what does all of this say about this wonderful technology?

Well, what this shows is that ion propulsion is an important tool in the toolbox of designers who want to push our capabilities to travel around the solar system. And indeed, that was the reason we flew it on Deep Space One. That was the reason the European Space Agency flew it on Deep Space One. That was the reason the European Space Agency flew it on its Smart One mission. And that was the reason that Japan included it on Hayabusa. Each of those missions had a strong component of testing the technology for subsequent missions. Now, each of those missions accomplished science in their own right. Now, each of those missions accomplish science in their own right, but again, these missions were principally designed to teach us how to use ion propulsion for these more ambitious missions, of which Dawn is an example. Are we still in the very early stages of development with ion propulsion? I think of some experimental programs, like maybe you're familiar with the one run by a former astronaut, Franklin Chang Diaz.

Yes, yes. The VASIMIR, I think it's pronounced. That's right. Well, that's still a more futuristic version. I would say we are not in the early stages anymore. I mean, we now have a mature capability to design, build, and fly missions with ion propulsion, and Dawn is an illustration of that. We're not learning new things in flying ion propulsion with Dawn.

We're taking advantage of what we learned on Deep Space One and simply applying it. Nevertheless, there are always opportunities for future, more sophisticated versions, and that's the sort of thing that Chang-Diaz and others are working on. You know, even with all of this news, this is still no more than sort of an interim update, because you're not going to reach Vesta for a while yet. When do you go into orbit around that asteroid? We will arrive in orbit in July of next year, so we still have 13 months to go, and we've already been in flight for more than two and a half years, so it's a long way to the asteroid belt, and it takes a lot of

work to put that spacecraft into orbit around Vesta. This will be the first time a spacecraft has orbited a body in the main asteroid belt, and then it will spend a year there scrutinizing it, studying it, and then it will leave orbit. It'll be the first spacecraft to orbit ultimately two destinations because after leaving Vesta, it will travel to dwarf planet Ceres and go into orbit around it. That's Mark Raymond, chief engineer for the Dawn mission, to our solar system's two biggest asteroids. We'll have more when Planetary Radio continues in a minute. 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. Thank you. Transcription by CastingWords 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 ion-propelled Dawn spacecraft is well on its way to Vesta, the second largest of our solar system's asteroids. After a year there, it will depart for Ceres, the queen of space rocks in our neighborhood. Mark Raymond of JPL is responsible for keeping Dawn on track for unprecedented science. Can you imagine even attempting a mission like this without a propulsion system like ion engines? No, a mission like this really would be effectively impossible with conventional chemical propulsion. I mean, for that matter, even a mission just to Vesta,

ignoring the opportunity to go on to Ceres, would be unaffordable within the constraints that NASA has. So ion propulsion really is enabling for this kind of exploration. What is so difficult about reaching Vesta? Well, there are several challenges in going to Vesta. One is that when we send a spacecraft into orbit around a distant body, usually that planet's gravity helps pull the spacecraft into orbit. And so when we go into orbit around Mars or Jupiter or Venus,

their gravity helps pull the spacecraft in. Vesta is a very large asteroid. Indeed, it's the second most massive asteroid in the asteroid belt, but it still doesn't have enough gravity to help with that. And the plane of its orbit is tipped from the plane of Earth's orbit, the plane in which most planets orbit the sun. And so it takes a lot of work to get Dawn into the same orbit around the sun that Vesta is in. Those sound perhaps like obscure technical details, but Vesta is a long way from the sun. It's much farther than Mars. And so together, this just makes for a mission that would be possible but unaffordable with conventional chemical propulsion. But then to have stopped at Vesta and then effectively launched from Vesta to go to another destination, Ceres, and stop there, that is truly beyond humankind's capability without

ion propulsion. It is quite a mission. Even more than a year out, is a lot of work underway figuring out exactly what will happen as you approach Vesta? We're working very hard on developing the exact details of the plan down to the level of timing of one second for how the spacecraft will approach Vesta, how we will navigate it into orbit, and what scientific measurements it will take as it gets there. We have completed the stage of developing the instructions that the spacecraft will follow

as it navigates its way into orbit, and we're at the tail end now of developing the same kind of instructions that it will use for the first of its intensive science orbits at Vesta. And by the time we arrive at Vesta, we will have developed virtually all of the instructions it will need for its one year in orbit there. Could you remind us very briefly of some of the scientific instruments Don will use to tell us more about these bodies? Of course. We have some cameras on board. All of us are visual creatures and we like to see pictures. So we'll be getting color pictures of the surface of Vesta. We also have a visible and infrared mapping spectrometer that will tell us what the minerals are on the surface,

essentially what kind of rocks are there. We also have a gamma ray and a neutron detector that will tell us what the atomic constituents of the bodies are, that is, what are the elements that make up Vesta and Ceres. And we also will make extremely, exquisitely precise measurements of the spacecraft's orbit, and that will reveal the interior structures. So we can determine, for example, whether Vesta has a core, perhaps whether Ceres has a subsurface ocean of liquid water, and that sort of thing. This is how we've been able to learn a lot about the Saturnian system, just from the Doppler effect, right?

Indeed it is. It reveals a great deal, and we're looking forward to finding out what the mysteries are of Vesta and Ceres. I hesitate to look out this far, but as you look out toward the end of at least the planned mission at Ceres, what's the end? What is the big finish for Dawn, or does it just fade away? Well, certainly I think its scientific legacy won't fade away, but I presume you're referring specifically to the spacecraft.

Yeah, I just wondered if you might want to try and knock it into that largest of all bodies in the asteroid belt. No, no, we certainly will not do that. Ceres is a very interesting body. I referred a moment ago to the possibility of it having a subsurface ocean of liquid water. And because of that, there are planetary protection rules in place to preserve this interesting, perhaps very important, biologically pristine environment. Just as we want to protect places like Europa and Enceladus. That's right.

And so the end of the Dawn mission is planned so that Dawn could not even accidentally crash into Ceres for a very, very long time. Moreover, the gravity is so large at Ceres. Again, it's not like these little chips of rock that most people think of. Even asteroids like Eros and Itokawa, fascinating though they are, are of a completely different type. Dawn would not even have enough thrust to make a landing at Ceres. And it really is a bit of a world unto itself, isn't it? I mean, it's a sphere. It really is. I mean, it's classified as a dwarf planet.

And in fact, in my view, both Ceres and Vesta are so large, they really are among the last truly unexplored worlds in the inner solar system. And that, to me, is one of the things that's so exciting about this mission. Lots to look forward to, Mark. You can bet that we're going to want to check in with you and maybe others on the mission as we head closer to that encounter with Vesta just a little more than a year away. Thanks very much. Again, I appreciate your interest and always happy to share with you what we're up to.

Thank you. And, by the way, live long and prosper. You do the same. Thank you, and by the way, live long and prosper. You do the same. Thank you, Mark. Mark Raymond is the chief engineer for the Dawn mission. He has been at JPL for a very long time, pioneering technologies like ion propulsion. We will continue to follow this very exciting mission. We'll follow Bruce Betts into What's Up.

That's just a few moments away here on Planetary Radio. We're out back at the new headquarters of the Planetary Society. You can hear the traffic going by across the Arroyo here in Pasadena, which the headquarters backs up to. I don't know why any of that is particularly significant, except to say that it's time for What's Up with Bruce Betts, the director of projects for the Planetary Society. Yes, and I'm pulling my inspiration from out of the Arroyo.

You've got to pull it out of somewhere. Fortunately, there's a bridge. So give us a bridge to the sky. All right, in the bridge to the sky, up in the evening sky, we've still got Venus looking righteously, awesomely bright in the west after sunset. And you will see to its right, Castor and Pollux, bright stars of Gemini. Go to the upper left of Venus, you'll see Mars hanging out kind of near Regulus, but getting farther away, the much bluer star than reddish Mars.

And Saturn farther to the upper left, and Mars and Saturn growing closer together. Very, very exciting, but not there yet. Saturn looking kind of yellowish. We also have in the predawn sky Jupiter over in the the east dominating, looking extremely bright. But we also have a partial lunar eclipse on the 26th. And it's visible in the Americas, it's visible in the Pacific Ocean, and from eastern Asia and Australia. Random, random, random. Space, space, space, space, space. Back, back, back, back, back, back, back. You know, you don't have to fake the

reverb, the echo. I actually provide that for you at no charge. Oh, I thought that was totally me all these years. Dang. Matt, do you know what's pushing on us right now? My responsibilities, my destiny. Well, all of that's true. Also the wind, but that's not what I'm talking about.

Radiation pressure. That's right, we're being pushed on by the very sunlight that illuminates the Earth. Can't you feel it? You big bully! Okay, the guard at the Federal Courts building is getting a little nervous right now. That's our neighbor here, by the way.

Not you, sir. All the time, light is pushing on us, but it's such a tiny, tiny effect usually, unless you go into the vacuum of space where you get rid of all those other pesky things like wind, and especially if you unfurl a big, bright solar sail, like Planetary Society's Light Sail 1 is going to try to do, but also radiation pressure responsible for pushing out the dust tail, responsible for pushing out the dust tail, one of the usually two tails of a comet,

pushed out by solar pressure, by sunlight actually pushing on the dust particles. Next week on this very program, we will be talking about light sail. Let's go on to the contest. Alright, we asked you last time around, what is the approximate diameter of the crater Copernicus on the Moon? A crater that you can see very nicely through a good pair of binoculars. How'd we do, Matt? Far and away the biggest response we have ever had to the competition. I don't think we can take responsibility for it. I think it's

that pair of Celestron binoculars, the 25 power Celestron from their most popular series, the name of which I don't remember at the moment, that really got people going. Either that or they're just in love with Coperticus. I'm telling you that from Cambodia to Brazil, from Australia to the truly exotic Hoboken, New Jersey, the answers just poured in. That's so cool. Are you sure it wasn't us? All right, all right, it was half us. Those weren't the binoculars I took home, were they? I don't know. Did you? Did you try them? Did you put them on a tripod? Because they have a tripod adapter. No, I'm just kidding. They're brand new in the box. All right, okay. I'm very happy to announce that Mark Detweiler

of Eugene, Oregon is going to be getting that pair of Celestron binoculars because he let us know that the lunar crater known as Copernicus is about 93 kilometers in diameter. Although it has rays that go out much further, right? It does indeed. It's one of the comparatively younger craters on the moon, which doesn't mean a lot for the larger craters. It's getting peppered by tiny stuff all the time, and it's thrown out what look like bright rays because it hasn't been aged carefully by the sun.

You won't be surprised to know several of our listeners couldn't stop at just giving us the diameter of the crater. They had to, as we love to do, put it in terms that are easily understood by the layperson. So Stan Furtig, Stan let us know that Copernicus would hold approximately 1,094,120 Big Macs. That seems off by two or three. No, you know what? It's, I got it wrong. It's not the volume. That's the diameter. You could put 1,094,120 Big Macs along that 93-kilometer diameter. Well, now it all makes sense. Bun Seat tests me on onions, pickles, cheese, lettuce, sauce, special patties, beef, all two. That's what happens if you line them up backwards. We should get binoculars from McDonald's.

I got confused because we did have one that was a measure of volume, and this came from Ethan Walker. Ethan wanted us to make sure that people know that Copernicus could hold 3.4 times 10 to the 15th gallons of Nancy's brand cottage cheese. Wow. Now, will that interfere with the cheese that the moon's made of? I don't know. You might get some kind of cheese reaction there. Do those go together? Yeah, I don't know. Well, thank you so much, folks. You know that we love to get those creative answers.

And we're not done, but yes, you have your hand up, sir? I do. I just want to point out, so it's basically a giant bowl of dips. So we could do this with salsa or cheese, you know, other kinds of cheese. I like the layered dips myself. We could do that. Make chips out of the asteroid belt. Okay, we're moving on to another contest. But what I was thinking, Bruce, is that, you know, we've mentioned in the past,

NASA's trying to decide right now who's going to get the space shuttles, the retired space shuttles. It's really a bargain. It's $28 million per shuttle, and that includes shipping. Wow. We thought we would help people who are interested in owning a space shuttle. And we figured we would do that by taking a collection up here. And I'm happy to say that we have collected $8.17. Yes.

We will give that to the winner of this week's contest so that you can put it toward purchasing your very own space transportation system shuttle. And we'll throw on a t-shirt as well. So here's the question. Why do you need, why should we help you buy your own space shuttle? Go to planetary.org slash radio. Tell us why we should give you that huge donation to your cause of buying a space shuttle. You're going to have the usual amount of time. You'll have until the 28th of June, June 28, 2010, at 2 p.m. Pacific time to get us your reason why we should help you get your own space shuttle. Not that this isn't serious, because this is serious, just like us.

Speaking of which, everybody go out there, look up at the night sky, and think about arugula. Thank you, and good night. I really hate arugula. I sneak it out of the bowl. I don't like to eat that stuff. It's bitter. He's Bruce Betts, the director of projects for the Planetary Society. He joins us every week here in this salad we call What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California

and made possible in part by a grant from the Kenneth T. and Eileen L. Norris Foundation. Keep looking up. Thank you.