Planetary Radio: Space Exploration, Astronomy and Science - Dawn Approaches Giant Asteroid Vesta

Episode Date: May 16, 2011

After three-and-a-half years of ion-propelled flight, Dawn is finally on final approach to Vesta. We'll get a mission status report from Marc Rayman. Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Dawn comes to ProtoPlanet 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. Frontier. I'm Matt Kaplan of the Planetary Society. Dawn is the ion-engine-driven spacecraft that will orbit the two biggest bodies in our solar system's asteroid belt. Mission Manager Mark Raymond is back with a status report, just as his probe has taken its first image of giant Vesta. No one is more excited about this imminent encounter than our own Emily Lakdawalla. She'll explain her enthusiasm in a few seconds, followed by our weekly commentary from Bill Nye, the science

and planetary guy. We wrap up with Bruce Betts, freshly returned from saving the Earth at his Near-Earth Object Conference in Romania. Time for the Planetary Society Science and Technology Coordinator. Emily, as you know, my guest today is Mark Raymond of the Dawn Mission, who has made all those wonderful contributions to the blog. And I will be telling him how excited you are about his spacecraft sneaking up on Vesta. Yeah, and I'm just, I can't wait to see every picture that's going to come down from the spacecraft because, you know, this is really a whole new class of worlds that we've never explored before. We've seen small moons in the outer solar system, and we've seen some fairly tiny asteroids, but we've never seen this class of really big asteroids. An asteroid doesn't do

them justice. They're protoplanets, and we've never seen anything like it before, so I can't wait. Well, we will ask him about that, and I'm sure we'll have him back on as that spacecraft arrives at Vesta, which is not very far off. Let's go on to a couple of the other blog entries from last week, both of which were written by guest bloggers. That's right. You know, I'm always looking for guest bloggers with interesting voices who know things that I don't. And, of course, I don't know quite a lot about space science. And their voices can be really interesting, and I've got several people who have volunteered recently to make contributions. One of them came out of the blue from a guy named Mike Malaska,

who wrote a blog entry that I've been wanting to do for a really long time that basically summarizes a huge number of the citizen science opportunities that are out there on the web and off your computer in order to contribute to the development of science as just a member of the citizenry. And this is what SETI at Home hath wrought. And there are all kinds of terrific opportunities. They're all there in the blog. We do think about SETI at Home, starting it with computers. But of course, citizen science goes way back with things like bird backyard bird counts, which have been done for quite a long time before SETI at Home ever came along.

And that, too, is citizen science. Even amateur astronomy has a long and distinguished history. And will continue to have a long and distinguished future. And speaking of astronomy, you have yet another guest blog entry about a magma ocean. Yeah, and this is really a pretty amazing story, because it's a discovery that was made by a spacecraft that's no longer with us, Galileo. And the reason that the discovery is being made now is because it took the theoretical guys quite a long time to develop a model that

can explain Jupiter's magnetic field. And once they accurately modeled Jupiter's magnetic field, they were able to subtract it from what they measured at Io, and they found that Io has its own induced magnetic field, which means it has to have a liquid layer. But unlike Europa and Ganymede, that liquid can't be water because of Io's intense volcanism, so it's got a magma ocean under there.

And that's really an exciting story, and I was very glad that Jason Perry wrote about it because he's been an expert on Io since he was in high school. And with that, Emily, we're out of time. We'll talk to you again next week when you're on the road. And I'll be featuring lots more guest bloggers in the coming weeks.

That's Emily Lakdawalla, the Planetary Society Science and Technology Coordinator and a contributing editor at Sky and Telescope magazine. Bill Nye is up next. The science guy Skyped in from his hotel room in Salem, Oregon, where he had just delivered the Willamette University commencement address. Hey, Bill Nye the Planetary Guy here. And this week, the interesting thing to

me is how certain members of the U.S. Congress are battling with other members of the U.S. administration to keep the United States from doing much space business with China. Now, it's not the Cold War anymore, everybody, unless you want it to be. You know, they say, keep your friends close, but your enemies closer. If you want, for some reason, to keep the Chinese space program near you, do business with them, for crying out loud. Let's get Chinese taikonauts on the International Space Station. We can all be up there getting along and having a good time. You may remember, if you're of a certain age, when the U.S. decided not to send teams to the Olympics in the former Soviet Union as a means of protesting. Well, that was somewhat effective. But if you really want to be effective, start

sending faxes in there. Start engaging people in countries that you're a little afraid of. Send them blue jeans. Get along with them. Have fun. We're more alike than we are different. If you want to keep the Chinese closer, let's put them at 350 kilometers straight up on the International Space Station. Oh, yeah. And by the way, the real goal is to explore space and make discoveries and find out things about the universe that we don't know for the betterment of all humankind. Oh, yeah, that too. We could do all that by engaging the United States with the Chinese Space Agency, not trying to keep them at arm's length. I'm telling you, you don't need me to

tell you this. You can look it up and up's where we're going. Up, up, up, out into space. I'm telling you. You don't need me to tell you this. You can look it up. And up's where we're going. Up, up, up, out into space. I got to fly. Bill Nye, the planetary guy. You and I and the rest of humanity are about to visit a world that has barely been glimpsed until now. After a very, very long trip, the Dawn spacecraft has almost reached Vesta, the second largest object in the asteroid belt out beyond Mars. One of its cameras snapped a first, distant image of the huge asteroid on May 3. Dawn will linger at Vesta for a year and then depart for even bigger series, arriving there in 2015. It's an amazing journey, made possible by the gentle but persistent propulsion provided by its ion engines.

Mark Raymond manages the mission from the Jet Propulsion Lab near Pasadena, California, but JPL is just one of the international partners in Dawn. I asked Mark to return to Planetary Radio with an update. Mark, thank you for returning to Planetary Radio, especially as things become even more exciting with the Dawn mission. What are you up to now? Well, first of all, thanks for having me back. I appreciate your interest. And Dawn is now in its approach phase to Vesta. So we have imaged Vesta twice with our camera in order to help refine the trajectory. That is, we use these pictures to help determine where the spacecraft is relative to its destination. We've now observed Vesta also with one of our spectrometers, and we're continuing to thrust

with the ion propulsion system, slowly closing in, getting ready to be captured into orbit. So how soon does that happen? Is that the next milestone when actually Vesta's own gravity takes over from the ion engines? Well, Vesta's gravity never takes over from the ion engines. Because of the unusual nature of a trajectory using ion propulsion, we continue to thrust with the ion engines right through capture. Now, that happens on July 16th. The spacecraft won't even know the difference. That will be exactly the same as any other day of thrusting we've done throughout the mission. We'll continue propelling ourselves with the ion propulsion system for another several weeks after that until we arrive at the first orbit from which we're going to begin our

intensive science data acquisition. And all of this after, well, what will be by that time, more than three and a half years of getting out there to this not-so-little body and matching its orbit around the sun. That's right. Normally for a planetary orbit insertion, spacecraft comes screaming up to the planet and executes a big maneuver to be captured into orbit. In contrast, Dawn has spent this more than three and a half years of flight gradually reshaping its orbit around the sun so that it's looking more and more and more like Vesta's orbit around the sun.

And so this summer, Dawn will just creep up ever so gently near Vesta as the two of them travel together around the sun. It will slip into orbit and then just continue maneuvering down to the science orbits that we want to use. And in doing this effort, how much of interplanetary space have you guys covered? As of today, the spacecraft has traveled about 2,670,000,000 kilometers since leaving Earth. Wow. That's a lot of space to cover, and much more to come, of course. What does Vesta look like at this point, if I happen to be standing on the Dawn spacecraft? Well, if you were on the Dawn spacecraft and weren't too cold and hungry, you might actually enjoy the view of Vesta. It's just large enough now,

actually it's been just large enough since the middle of April, that to your naked eye, it would appear as a tiny disk. That is, it would no longer be just a pinpoint of light, like the stars and other planets in the solar system. But it still would be pretty small. Even with our camera, we just took pictures the day before yesterday, and Vesta was only about six pixels across. But it won't be much longer before it grows large enough to really reveal some exciting new landscapes. How long before you have a better view of Vesta than we've been able to pick up from any other instrument. Well, the best views so far are from the Hubble Space Telescope,

and we'll get views comparable to that in about the second week of June, and then they'll only get better after that. You said that not only are you beginning to snap these images, but a spectrometer is in use. Is that picking up real science now, or is this calibration? What's going on? No, this is more for calibration. Vesta is still, again, too small and too far away to reveal anything new to the spectrometer, but the reason we wanted to observe it is so we can set the parameters for future observations. About half a dozen times between now and the time we arrive in our first science orbit, we'll observe Vesta again with the spectrometer.

Gradually, Vesta will be larger and larger, and we want to be prepared for those times with proper settings for how we acquire the data. That spectrometer is just one of the instruments that goes beyond your cameras that will be telling us much more about the composition of Vesta, I think. That's right. That spectrometer we're using now will tell us about the minerals on the surface, essentially what kind of rocks are there. We also have a spectrometer, which is already operating,

that measures radiation, gamma rays and neutrons, and that will tell us what the elements are, what the different atomic constituents of the uppermost meter or so of Vesta are. And then when we get still closer, we'll be measuring the gravitational field, and that will tell us about the interior structure of Vesta, that is, how is the mass distributed. I was surprised to see that among the many mysteries that remain about Vesta are even things as basic as its mass. That's right. It's actually interesting that the mass has been estimated in part by how much Vesta perturbs the orbit of Mars. Really? Oh my God.

It's amazing. Now, most of the measurements come from how Vesta perturbs the orbit of Mars. Really? Oh, my God. It's amazing. Now, most of the measurements come from how Vesta perturbs the orbit of other asteroids, but Vesta is the second most massive body in the asteroid belt. It's a big place, and its effect on Mars has indeed been measured, and that has helped us estimate what the mass is. But, of course, until we get a spacecraft there, we won't really know for sure. That's Mark Raymond of the Dawn Mission now closing in on Vesta in the mass is. But of course, until we get a spacecraft there, we won't really know for sure. That's Mark Raymond of the Dawn mission now closing in on Vesta in the asteroid belt. He'll tell us more in a minute. This is Planetary Radio.

I'm Robert Picardo. I traveled across the galaxy as the doctor in Star Trek Voyager. Then I joined the Planetary Society to become part of the real adventure of space exploration. The Society fights for missions that unveil the secrets of the solar system. It searches for other intelligences in the universe, and it built the first solar sail. It also shares the wonder through this radio show, its website, and other exciting projects that reach around the globe. I'm proud to be part of this greatest of all voyages, and I hope you'll consider joining us. 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. Our nearly 100,000 members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. Nearly 100,000 members received 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. Dawn is about to break over an asteroid or protoplanet called Vesta. The dawn we're talking about is an emissary from Earth that has already traveled

billions of kilometers. Mission Manager and Chief Engineer Mark Raymond of JPL reminds us that Vesta is very big. Now, of course, you said the second biggest. The biggest is just a little farther down the schedule. That's right. The largest, most massive body in the asteroid belt is Dwarf Planet Ceres, and we will go there after we're finished at Vesta. We'll arrive in 2015, and one of the unique and I think really exciting things about this mission is it's going to be the first spacecraft to orbit two different solar system targets, and I think that's really cool. It's truly an interplanetary spaceship. Beyond cool. And is it really these ion engines that are enabling you to accomplish all of this?

It absolutely is. A mission even only to Vesta, which is the easier of the two destinations to reach, would have been unaffordable within NASA's discovery program without ion propulsion. within NASA's Discovery Program without ion propulsion, and a mission to both Vesta and Ceres would be simply impossible without it. It really is what enables us to undertake this exciting mission and to do this important science. Tell us how the spacecraft is doing otherwise. I know you had trouble with one of those reaction wheels that helps you orient it. That's right. So we had four reaction wheels.

We need three, and these are devices. They're like massive gyroscopes, which we spin electrically. Like big flywheels. That's right. And by changing the speed that these devices spin, we can rotate the spacecraft. We have four of these on board. We need three because we always carry a backup, and our backup failed in June of last year. So the spacecraft has continued operating just fine. We haven't lost any time or given up any capability.

It's just that we no longer have a spare reaction wheel. And so, in fact, last month, we transmitted new software to the spacecraft that would allow it to operate with two reaction wheels in the event that we have a problem with one of the others. But at this point, all three are healthy, and the spacecraft is performing just beautifully. And so we're looking forward to using them to get great science data at Vesta. And we should say this is very tried and true technology. They do the same kinds of things out there on Cassini, which we were talking about just

a couple of weeks ago with your colleague at JPL, Linda Spilker. But let's talk about that software upgrade. This has got to be a little bit more nerve-wracking than, oh, when I upgrade Windows on my machine. Well, that's true, but this was the fourth time we've installed new software on the spacecraft since it was launched. So we had plenty of experience with it from before, and the procedure went absolutely flawlessly. before, and the procedure went absolutely flawlessly. Nevertheless, as you observe, it's something you have to be pretty cautious about because the computer is constantly in control of the spacecraft. It's controlling its orientation. It's controlling temperatures.

It's monitoring all of the subsystems on board. And to begin running the new software, of course, we have to reboot the computer. And so there's a short time when the spacecraft has to get along without the guidance of the master computer. But again, we practiced that before launch. We understood how to do it. And it's gone extremely smoothly, four out of four times in flight. So while it's gone extremely smoothly four out of four times in flight. So while it's not something we take lightly, we understand how to do it pretty well. Got to be somewhat scary when it comes time to do that upload, though. It's not so much scary as just we have to devote an extra level of attention and care to it, and that pays off because, again, it's worked well.

Of course, it's your job, the rest of your team, the engineering team, to make sure that this spacecraft arrives safe and sound and is fully capable of beginning to do its part for the scientists, your colleagues around the world who are looking forward to getting this data. How does the interaction between those two groups work? They've got to be getting awfully excited as data starts to flow. They absolutely are very excited, but I can't say that they're any more excited than the rest of us. To me, this is an adventure not just for the scientists, but for everybody. I mean, we all share in the

excitement of exploring a brand new world. Not only everyone on the Dawn team, whether scientist or engineer, but I think everybody who has a passion for the cosmos, everybody who has a curiosity about what's out there in the universe and what's our place in it, I think we all can share in that excitement. Well put. And I can tell you what you already know, one huge fan that you have, Emily Lakdawalla, who we were talking to, as we do every week here, just a few moments ago, science and technology coordinator for the Society, but also the editor of our blog. Which I love reading. You and so many other people.

It is terrific. And she has this very excited, very enthusiastic entry in the blog that finishes with, let the mapping of a new world begin, even though we're still a few weeks off from that mapping, I think. Still very well put. And you're a contributor to that, of course. We will put up a link to your latest Dawn Journal entry, as well as to the dawn website where people can hear this show or at planetary.org slash radio we'll look forward to the next one of those installments well thank you very much i really appreciate your interest and i'm glad so many people are going to be along as we do indeed explore this alien exotic mysterious world i think there are going to be a lot of exciting things to learn there

about the dawn of the solar system. And, Mark, I hope we can talk to you again when we hit one of those upcoming milestones or kilometer stones. That would be my pleasure. Thanks, Mark, very much. Mark Raymond is the chief engineer and mission manager for the Dawn mission, now closing in on Vesta, as you heard, the second largest object in the asteroid belt, one that still is quite mysterious to those of us back here on the home planet,

but that mystery is beginning to be unveiled as Dawn approaches this body. I'll be right back. We'll see if we can unveil some mysteries about the night sky with our friend Bruce Betts for this week's edition of What's Up. Bruce Betts is back from Romania. He is the director of projects for the Planetary Society, and he's come around once again via Skype to tell us about what's up in the night sky, but how did it go over there? It went great. It was very interesting. Planetary Defense Conference and talking about protecting the Earth from near-Earth asteroid impacts and all manner of topics from finding them to political aspects to mitigating and deflecting them.

And you were there representing the Planetary Society, no doubt. Oh, yes, I was. And in fact, you can there representing the Planetary Society, no doubt. Oh, yes, I was. And in fact, you can go to the Planetary Society website. And I wrote a couple blogs while I was there. And I'll have another one in the next couple days, summing up the meeting with some more detail. Good. I enjoyed reading about your experience right there in the blog. What is up in the night sky? Still what's up in that pre-dawn part of the night sky that's impressive. A whole mess of planets over there in the east, low in the east before dawn, still doing their dance, getting close, moving apart. Dance, dance, dance.

Venus is the super bright one. Jupiter also extremely bright near Venus. And then Mercury much dimmer, but still bright and white, and then Mars dim and reddish, all moving around in a fun sight for the next couple weeks. Evening sky, we've still got Saturn hanging out over in the east in the early evening and high overhead in the middle of the night. And more stuff up in the sky when we get to answering the trivia contest this week. There's some fun stuff there.

We have This Week in Space History. It was Apollo 10's week back in 1969. Apollo 10's the one you always seem to be traumatized by the concept of going down to 50,000 feet above the surface of the moon and then having to leave again. Just not fair. Although some of them got to go back. That's true. We move on to random space fact.

Surprise finish. The meeting where the Planetary Defense Conference was held, the Parliament building of Romania. First of all, random building fact. It is apparently, according to the Guinness Book of World Records, the world's heaviest building. Really? Which I just think is such an incredibly random thing that people even came up with. Heavier than the Pentagon. Heavier than, I mean, any number of other buildings

that would have come to mind first. I'm going to have to look it up. That's what they say. I did not confirm it. They also are the largest civilian office building by volume, I assume, in the world, which is eclipsed only, I believe, by the Pentagon. That makes sense.

That, and I'm sure the weight is explained by their opting for the neutronium floor tiles. Yes, and the depleted uranium chandeliers. But here's my twist. I was staring at it after a couple days there and thinking about it and remembering the dimensions I'd read and thought, hey, wow, how appropriate and weird. This building is almost exactly

the size of the asteroid Apophis. Is that right? How appropriate? At least in its longest dimension is Apophis' best, we know, longest dimension, 270 meters. Fascinating. And it has a similar width in a different direction. So it's

very similar in size. So we're glad the Romanian Parliament building Fascinating. We can do the follow-on of, you know, which is more massive, Apophis or the Parliament Building. I'll look into that. Okay. We move on to the trivia contest. We asked you what celestial event was James Cook on his first voyage headed to the South Pacific to observe a rare celestial event? How did we do? And you may remember that I became very excited when you posed this question a couple of weeks ago.

You did indeed, because you knew it. I am reading a book in which this is sort of the first major event in the book, this trip, the first voyage by James Cook to the South Pacific. The book is wonderful, by the way. It's called Age of Wonder, and it covers roughly like 1780 to 1820 or so. This incredible blossoming of science in the Romantic Age and how closely it was tied to art.

So highly recommended, The Age of Wonder. You didn't want to hear all that. You just wanted to hear why. And Hunter Odom told us why. Hunter Odom of Marion, Illinois, came up with the answer. You want to give it to us? Oh, I'd be happy to. A transit of Venus, so Venus passing in front of the sun. Hunter, we're going to send you a Planetary Radio t-shirt for being the one chosen by Random.org for that. And Hunter, by the way, is a first-time winner, as far as I could tell.

Got some other very interesting responses. I had no idea until I read Ilya Schwartz's response that these transits come in something like a 243-year repeating pattern. I guess there'll be another one in June of 2012, and then it's going to be a long time after that, 2117. Yeah, we had one just a few years ago, and then we'll have this one in 2012. Don't miss it, and then it'll be a while. One quibble from David Kaplan, regular listener, David Kaplan, no relation. Those Kaplans, they're problematic. He said there was some road noise when he was listening to you ask the question.

He was pretty sure that you asked about James Kirk, who, of course, was not captain of the Endeavor. He was captain of the Enterprise, as we all know. Why did James Kirk go to the South Pacific? I know why. I think for an excuse to take his shirt off. Yeah, I think so, and probably meet some chicks. But that's what he used to do. That's really what the galaxy was all about for old Jim.

Old Jimbo. You know him well. Well, I was just quoting Spock. What do you got for next time? For next time, hearing an awful lot about near-Earth asteroids discovery, so we're going to stick on that theme for a moment more and ask, during 2010, what sky survey, so what set of telescopes that are part of the same search of the sky, discovered more near-Earth asteroids in 2010 than any other survey?

Just in that year. Okay. Yeah. Well, I thought I'd make it more specific. They actually have led for a few years now. But let's go with 2010 to make it precise and go to planetary.org slash radio, find out how to enter. You have until Monday, May 23rd at 2 p.m. Pacific time to get us that answer. Thank you so much and welcome home. Thank you. It's good to be home. I might be around for a while. Here's hoping. All right, everybody, go out there, look up at the night sky and think about really, really long plane flights. Thank you. Good night.

Well, you're home now. He's Bruce Betts, the director of projects for the Planetary Society, and he joins us every week, no matter where he is, for What's Up. Einstein was right, again. We'll find out why when we talk about Gravity Probe B next week. 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. Clear skies. Thank you.