Planetary Radio: Space Exploration, Astronomy and Science - Leaving for Jupiter with the Juno Mission's Scott Bolton

Episode Date: June 27, 2011

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The next mission to Jupiter, 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. Sometimes a half hour just isn't enough time to bring you the Universe, no matter how hard we try. We'll just tease you with a few seconds of Bill Nye the Science and Planetary Guy in front of an enthusiastic audience. Then stick around for a talk with Scott Bolton, principal investigator for the Juno mission, leaving for Jupiter in barely a month. Finally, a quick visit with Bruce Betts for this week's What's Up. It begins now with the Planetary Society's Science and Technology Coordinator, Emily

Lakdawalla. Emily, good to have you back again. And I think this is going to be a weekly thing for a while as we see Dawn, see Vesta closing in. Yeah, Dawn's getting closer and closer and Vesta's beginning to come into focus. I think last week when I first posted some images of Vesta, it was really hard to see any detail. A lot of people were seeing faces and monkeys and other stuff in the images of Vesta.

But this week, you really can see that Vesta looks very battered. It's got some pretty big and deep craters in it, which is kind of surprising given its size. You can see those rotate into view with the animation that they released this week, which contained quite a number of their images. You call particular attention to what can be seen at the Terminator. Anybody who's ever pointed a telescope at the moon, a half moon, knows why. That's right. And I suppose I should be very careful to define Terminator because those of you who are astronomers know what I'm talking about. The rest of you are probably thinking of Arnold Schwarzenegger.

The Terminator is the day-night boundary on a world. It's where the sun is either rising or setting if you were standing on the surface of the world. And on one side, you have sunlit terrain. And on the other side, you have night terrain. And that's where you can see the best topography because the sun is coming in at a very low angle. So that's where you can really pick out details of craters. You make a comparison. You talked about this body already being obviously much more irregular than we thought. You compare it to yet another body, though a much smaller one. That's right. I showed a picture of Janus, which is kind of similar in shape, and it seems to have similarly deep craters on its terminator. But it is much smaller. It's only about a third the diameter of Vesta. Vesta is huge. And it's kind of surprising to see such a

large body have such deep craters. Now, of course, these are preliminary images, they're rather fuzzy, you know, it might just be that I'm getting the wrong impression from interpreting fuzzy images. But really, Vesta looks like a very deeply battered place. And part of the reason for that is because it's made of rock. It's not made of ice like these other smaller worlds are. And rock can support much more steep topography than ice can. So it shouldn't be a surprise that it would have some more steepness. But it is still surprising.

Well, much better pictures, pictures no doubt by next week when we speak again let's very briefly talk about one other project that you mentioned earlier on the blog and this is another terrific example of citizen science yeah and this is one that i am incredibly excited about this is actually the first one where i find myself going back to it every night before i go to bed to do some work on ice hunters. And the idea behind ice hunters is that we have to look through about 5 million images that they've taken so far of star fields in the area where New Horizons will be heading after it passes by Pluto. Because New Horizons is going to go on to a much smaller Kuiper Belt object, but the catch is that that object hasn't

been discovered yet. And that's what they're asking the public to do, is to pour through these star images and try to find the little blob of light that represents an undiscovered Kuiper Belt object that New Horizons might just go on to visit. And Alan Stern has been telling us all along as he's talked about the New Horizons mission that this would be the next target, so people can help find it.

We'll put that link to this project up where you can hear this show, find this show at planetary.org, or just check out the blog with Emily. Emily, once again, thanks. We'll talk to you next week. All right. See you then, Matt. One of the distinguished speakers this year was our own Bill Nye, Executive Director of the Planetary Society. I wish I had time to share more of his remarks with you. You can hear a few extra minutes in this week's edition of Bill's Your Place in Space feature. It's on this week's show page at planetary.org.

Here's just a tiny sample. This is a picture of Saturn taken by the Cassini spacecraft a couple years ago. Astonishing picture. The spacecraft is out beyond Saturn, pointed back to the Earth. You see the sun just glinting, glimmering around there about the seven o'clock position. And there's the only night on Saturn is in the shadow of the rings. But wait, wait, there's more. It's not only a picture of Saturn, it's a picture of the Earth. See it right there. And when you download super high resolution version of this, you can see the moon, the Earth's moon, right there. So this is a remarkable photograph taken by a society that used its intellect and treasure to explore, to reach

out. And as I always say, space exploration brings out the best in us. And if you stop looking out, if you stop exploring, what does that say about us? It says we're content to stay home. We're content to not find out about our place in space. Bill Nye, the science and planetary guy at the Skeptics Society's Science Symposium on June 25th. Ready for a trip to Jupiter? Juno starts its long journey there in early August. Scott Bolton is Juno's principal investigator. Scott also directs the Southwest Research Institute's Space Science and Engineering Division and has had a hand in many previous missions.

He was in Florida all of last week overseeing the final preparations for launch. It's really an exciting time. I'm here right now at Kennedy Space Center, and in fact they're preparing for the next shuttle launch, which is also exciting to see. Our spacecraft is already getting ready, getting ready to get fueled. It's getting its final test done. It looks beautiful. The solar panels are attached. Everything's on. They're covering it with thermal blankets, and we're getting ready to move it over and mate it to the rocket. It's really exciting to see. We're just a little more than

about a month away from launch, August 5th. We have about three weeks at which time Jupiter and Earth are aligned, and then they start to separate away, and we have to wait another 13 months if we were to miss that window. And how long before you arrive at Jupiter? It takes us five years to get to Jupiter. Jupiter is really far, and of course we go out in a spiral. years to get to Jupiter. Jupiter is really far. And of course, we go out in a spiral. What we do is we launch and then we go around the sun. And two years later, we come back and meet the Earth. And we get a close flyby of the Earth. And that gives us an extra gravity boost. It kind of accelerates us and points us toward the right direction. And then it's

three years from then to get to Jupiter. So it's five years altogether. By the way, I want to refer people to an absolutely stunning website that apparently you developed with the folks at Radical Media that looks like a really good episode of Nova on PBS. It's so well done. We will provide the link to that at planetary.org where people can find this show as well. It's just beautiful if people want to learn more about the mission.

But that's where I saw that you guys are really taking that old NASA phrase, follow the water, to the extreme, aren't you? We sure are. We're following the water. In this case, it's the early solar system water. And what we're after is we're trying to discover the recipe of how you make planets. And water is a key ingredient. In fact, you start with trying to figure out a recipe by looking up the ingredient lists. And that's just what we're doing. And one of the main ingredients, which is water, we don't know how much of it is in Jupiter. And so that's part of what Juno's about. Why will looking for water at Jupiter tell us more about how our solar system and how our own planet came to be. First of all, water is really important throughout the universe. Most of the universe is hydrogen

and helium. And the next most abundant ingredient is oxygen. So the most common molecule, at least multi-element molecule, is probably water. What we think happened early in the solar system is there was a big cloud, mostly hydrogen, helium, pretty much the same stuff the sun is made out of, and that collapsed and formed the sun. And then what was left over, most of what was left over, went into Jupiter. It has more material than everything else in our solar system combined, other than the sun. So if you put all the planets, they fit inside Jupiter. And so it sucked up most of the stuff that was left after the sun formed. What we found out with Galileo probe and some other measurements that have been made from other telescopes is that

Jupiter's enriched in what we call heavy elements. It has a little bit more of carbon, nitrogen, sulfur, the noble gases, all this stuff that we cosmologists call heavy elements, which is just everything beyond helium in the chemistry table. It has a little bit more ratio-wise than the sun does. And we don't really know why or how that happened. And of course, it's important to us because all that stuff that we call heavy elements is actually what we're made out of. That's what the Earth is and that's what life came from.

And scientists think that the way it worked was the sun formed and then the rest of the material started to cool off and expand and water molecules started to form as ice and the ice trapped these heavy elements that were left. And you had these little tiny balls of what they call icy planetesimals, little tiny comets, if you will, really tiny. And they were enriched. They had all of the solar nebula composition minus the hydrogen and helium. So it was all like water ice with carbon, nitrogen, sulfur, all these other enrichments. And when Jupiter formed, those things

must have formed already and they got sucked in. This is a theory. We've never found these little icy planetesimals. But when we go to look at what Jupiter's made out of, how much water is in it is key to unraveling the mysteries behind this theory. And that's why water's key. What instruments does Juno carry that are going to reveal this information about the planet? So we carry a number of instruments that kind of look through the cloud layers of Jupiter into the interior, sort of the invisible. In order to get water, we use what's called microwave radiometers.

So we have some microwave antennas, six of them. Some of them are shaped like flat panels and some of them are horns, depends on the frequency. And what they do is they listen to Jupiter. They listen to the microwave radiation that's coming out of Jupiter simply because it's warm. It's glowing in black body radiation. And it's different temperatures in its atmosphere as you go down, glow at different frequencies. And what we do is we listen and we measure that temperature very precisely at many different levels inside Jupiter. So we're sort of seeing inside because the lower part is glowing and it escapes out and we measure it. How far down into that thick atmosphere will you be able to see or at least sense? We'll see down about a thousand bars

of pressure. One bar of pressure is what we experience as sea level. And the trick that Juno uses is how far down we see in the microwave is dictated by the absorption of water and ammonia. By unraveling how deep we're seeing based on the temperatures that we measure, we can then say and predict how much water was in our path on the way out. In other words, if there was less water, we'd see deeper. And if there's more water, we'll see less deep, more shallow. And so we can gauge how much water is in Jupiter by how deep we see. We've got more from Scott Bolton, principal investigator for the Juno mission to Jupiter. Planetary Radio returns in a minute. 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. 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. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. First there was Voyager, then the Galileo orbiter. Now it's time for another even deeper look at our solar system's biggest planet. The Juno mission leaves as soon as August 5th for Jupiter. Principal Investigator Scott Bolton has shared with us

how his spacecraft will probe deep into the thick clouds surrounding that world, but Juno will be doing much more. Now, you haven't mentioned a camera yet, but you could not go to this beautiful planet without taking along something that's going to snap some images. I agree. And, in fact, that's the reason we have something called JunoCam, which is built by Mike Malin of Malin Spaces.

Good old Mike Malin. He builds lots of cameras for the Mars programs. And he gave us one to use. And we're going to be able to take pictures of Jupiter's poles for the first time. Plus, we get incredibly close to Jupiter. So we see really close up. We have like three kilometer resolution or something. So we'll see the clouds, these swirling, beautiful clouds, really, really close. And that camera is not a scientific camera, but actually a public outreach camera. So those images are intended to just be

obtained by NASA and then immediately put on the website or some medium that the public can grab right away. In fact, we're going to put the raw data out and let the public play with how to make the pictures out of it. That's going to be music to the ears of my colleague, Emily Lakdawalla, and you can bet that she's going to dig. She and her colleagues are going to pull some wonderful stuff out of those images that I bet will surprise even you and your folks.

Now, you're going to be getting pretty close. How close in will Juno fly to this planet? Well, each orbit we get what's called a perijove. The close approach to Jupiter is about 5,000 kilometers above the cloud tops. So we're really skimming right over the cloud tops of Jupiter. I love that term, perijove. How are you managing to pull this off without the electronics in Juno just being fried by that horrible radiation? Right.

I mean, Jupiter is completely surrounded by radiation belts, like Earth has Van Allen radiation belts. Jupiter's got more intense ones. So what we're doing is we're diving actually beneath those. There's a little gap between those and Jupiter, but we're still going through some pretty intense regions, probably the most intense in the whole solar system other than just going right into the sun. The way we do it is Juno is very much like an armored tank. We've got a vault, literally what we call a vault in the center of the spacecraft that has all the sensitive electronics in it. And that vault is made out of titanium. And we stick all the

electronics in there, close it up, and protect it that way. Now you're bringing something else that far out that no other spacecraft has taken to the outer solar system. And those are these solar panels that we mentioned up front, which is a pretty amazing innovation. You're the first guys to do this. We are. We're taking the solar arrays out further than anyone's ever done before, out to the outer planets. We're kind of pushing the envelope of solar power. Our solar arrays are huge. We have three of them. Each one is about eight and a half meters long each. So they're like the size of a tractor trailer. They're pretty big. And even with those three giant solar arrays going to Jupiter,

where Jupiter's, you know, five times the distance away from the sun that Earth is, we only get enough power to power a couple of light bulbs. So what we're doing is we're both energy efficient. We're designed to be very, very energy efficient and use every watt we can. But we also had to customize the solar array so that they could deal with low light intensities, very cold temperatures, and the radiation that I spoke of earlier. That's also a killer to solar panels. And so we have special glass over the solar panels to protect them as well. This is a pretty green spacecraft. We're green. And I'm happy to say we were green before it was meant to be green.

We designed this a while ago. I got to cover at least one more thing because I had such a good time learning about it. And that was how this spacecraft got its name. And the story that you were told about Juno, the wife of Jupiter, that made it so appropriate for what your mission is all about. Right. We named our mission Juno. And Juno is the Roman name from Greek mythology of the wife and sister of Jupiter. So Jupiter was the king of the gods, and Juno was

really the queen of the gods. Back when we were forming the team and forming the mission, I had a contest for all the different names, and people were trying to think of things. And a friend of mine was a mythology expert, and he sent in this story. And when we read it, we said, oh, that's it. And the story goes that you know juno was married to jupiter but jupiter was uh not always uh well behaved and he was sort of misbehaving and he got around yeah you know and so he uh was doing some stuff that he knew she wouldn't appreciate and he looks out and he sees her coming and he says oh i'm going to cast a veil of clouds around myself. So he puts this

thick layer of clouds around him so that she couldn't see. But of course, Jupiter was a god too. And she had special powers and just said, oh, I know what's going on here. And I got to go see through those clouds and came down and kind of used her special powers to see right through to see what Jupiter was up to or what his true nature was. And in fact, that's just what our spacecraft does, is we use these special instruments, sort of magical ones, to see right through the clouds. So we see through the clouds with this microwave radiometry to get the water and see deep in the atmosphere. We use gravity signals to see down to the very center of Jupiter to see if there's a core of heavy

elements in the middle of it. And we use a magnetometer to measure the magnetic field of Jupiter, which is an invisible force field coming out of the middle of Jupiter. Scott, somewhere up there, there is a Roman emperor smiling down on your mission, and we will wish you all the best, both with this launch and over the next five years as it makes its way out to Jupiter. And we'll spend, what, I think one Earth year out there circling the planet. That's right. Thank you.

I really appreciate the opportunity to talk to your audience and let them know about the excitement of Juno. Check out our website. Oh, yeah. Once again, you have to see, first of all, just the regular website. But we'll have a link up to that and to the one that Scott developed with Radical Media, which I highly recommend. It tells a very dramatic and quite beautiful story. The graphics are truly amazing.

Scott, best of luck once again, and thanks. Thank you. Scott Bolton directs the Space Science and Engineering Division at the Southwest Research Institute. By the way, his colleague there, Alan Stern, is the PI for the other NASA New Frontiers mission. That's the one headed out to Pluto that we talk about on this show, New Horizons. But for this conversation, we've been talking with Scott as the principal investigator for NASA's Juno mission to Jupiter, which lifts off, as he said, less than a month from now

if things happen at the beginning or the opening of that launch window. I'll be right back with Bruce Betts for this week's edition of What's Up. We'll look at the night sky, maybe we'll give away a t-shirt. Bruce Betts is on the Skype connection. He's the director of projects for the Planetary Society. It's time for What's Up on Planetary Radio. We're going to hear about what's up in the night sky and some fun trivia stuff. And I bet he's got other things in mind. Hi.

Hey there. Hi there. Ho there. We're as happy as can be. Yes, we are. I have my little Mickey Mouse in the spacesuit right above my head. I'd forgotten he was up there, and I'm looking up at him right now, and he looks so happy. I'm sure he is.

Zero G. So what's up? We still have a supernova that is bright, although bright only for something that's really, really, really, really, really far away. So if you've got a hardcore amateur telescope, say 8 inches or above, you can still see it, but apparently it is starting to fade now. That's the one in M51 in the Whirlpool Galaxy. For those who want to check out easier-to-see objects, we've got Saturn in the evening sky, high in the west, looking yellowish,

and it's got its little friend, Poryma, dimmer star that's only a half a degree away from it. For a challenge, you can try to check out Mercury shortly after sunset over in the west, but it is awfully low down. And in the pre-dawn, no problems seeing Jupiter in the east dominating the super bright, and down below it, ways near the horizon, is dimmer Mars. Let us move on to this week in space history. A couple of pieces from Russian space history. 40 years ago this week was the tragedy of the Soyuz 11 crew dying during re-entry. Farther back, a different kind of disaster, in 1908, the Tunguska impact,

a large airburst asteroidal impact that leveled 2,000 square kilometers of forest. Which is probably a good thing, because if it weren't for Tunguska, we'd have to go back to, oh, the time of our trivia answer today to say, see what they can do? Exactly. No, it was, and it hit in Siberian, as far as we know. No humans were killed by it anyway. So it is a good reminder to point to that that kind of impact happens on average, perhaps every thousand years or every few hundred years. All right, on to one-term spaceflight.

Anybody remember the sound of Saturn rotating last week that Don Garnett played for us? This was apparently Bruce's impression of it. I wasn't even trying, but it just happens naturally. So Mercury, the planet, before the 4th century B.C., Greek astronomers believed the planet to be two separate objects, one visible only at sunrise, which they called Apollo, and the other visible only at sunset, which they called Hermes. I got a little confused of it, of course, being an inner planet,

only visible fairly low to the horizon, and only in the evening or the pre-dawn. Truly interesting. All right, we will move on to the trivia contest. We talked about the stratigraphic layers around the world at the K-T or Cretaceous-Tertiary boundary that are enriched in an element that is uncommon in the Earth's crust, but common in asteroids and comets.

And its discovery in these layers was key to the adoption of the impact theory of the extinction of the dinosaurs and 70% of the species on Earth. What is that element? How'd we do, Matt? Well, Alex, what is iridium? Ding! We only got one person, Tom Burns, our barbershop quartet friend, who said that I was

very close with peanut butter, as long as I meant chunky. He said, though, that the correct answer was Velveeta. So, I'm sorry, Tom. Well, they did find more than one thing. Yeah, a couple of people said that, actually. But I said an element. So, I'm sorry, Tom. Well, they did find more than one thing. Yeah, a couple of people said that, actually. But I said an element. Yeah, right. Velveeta is as fun as I am of it.

Not yet on the periodic table. Exactly, right. It's a noble cheese. Now, we did get a correct answer, I'm very happy to say, from Jeremy Woodard. Jeremy Woodard in Visalia, California. I think, I didn't actually check this time, but I believe that's a first-time winner. And he, of course, did say that it was iridium, that very rare element. It was not illudium, David Scurlock wanted to point out.

Illudium, which was used in the Illumium Q36 space modulator. Nice. We had a lot of people point out different qualities, properties of iridium, like it's incredibly corrosion resistant. Several people pointed out that it is used for the mirrors in

X-ray space telescopes. Camille Stefaniak, I think, nailed it when he said, dinosaurs died so we could have X-ray telescopes. It's a fair trade, I think. Well, that's one way to look at it. And X-ray telescopes have never tried to eat anyone. That's a plus. Anyway, we're going to send Jeremy a Planetary Radio t-shirt.

What's next? We're going to stick with Mercury and fly into the scary world of general relativity. A rather specific one for you all out there this time. How much in arc seconds per century does the periaps of Mercury's orbit precess around the sun purely as a result of general relativity so are you kidding are you kidding me okay you know i do you know the answer i don't know i don't think anyone living knows the answer no that is so not true this is actually his so it was actually observed even in the 1800s. They added up their reasons you can predict why the orbit basically processes.

It rotates around the actual point of periapsis, rotates around the sun over time. And you can predict it due to the tugs of other planets, things like that. And they were coming up short. And then it turns out general relativity predicts the missing amount of precession, or at least pretty much all of it. And so it's significant also as one of the first proofs, or the first proof, that general relativity was not just a practical joke, although I still question that. I know. Einstein still frightens me. Would you give it to us one more time and then we'll tell people how they can enter.

How much in arc seconds does the perigee of Mercury's orbit process around the Sun purely as a result of general relativity? So the amount of precession from general relativity alone, phrase it in the form of a question. No, you don't have to do that part. Go to

planetary.org slash radio. Find out how to enter. And you have until the 4th of July, July 4 at 2 p.m. Pacific time to get us this answer. All right, everybody. Go out there. Look up at the night sky and think about smoke. Thank you and good night. And he ain't just blowing smoke.

He's Bruce Betts, the director of projects for the Planetary Society. He joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California and made possible in part by a grant from the William T. and Kathleen L. Norris Foundation. Clear skies. Thank you.