Planetary Radio: Space Exploration, Astronomy and Science - Off to Pluto and Its Three Moons with Alan Stern

Episode Date: November 21, 2005

New Horizons PI Alan Stern on the mission to Pluto, and discovery of 2 new moons. Q&A: movies from rocket launches. New trivia contest.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

We're off to Pluto and its three moons, this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. Alan Stern returns to our microphone to talk of the ninth planet, and what we used to think was the outer edge of the solar system. Alan is in Florida making final preparations for launch of the New

Horizons mission, our first human emissary to Pluto. He'll also talk about his recent co-discovery of two new moons, circling that cold ball. And Bruce Betts hungers for your attention and lunch in What's Up. We've also got a Planetary Radio t-shirt for this week's space trivia contest winner. Let's see what's happening around the solar system.

Our first stop is a rock about 180 million miles away from home. Has Hayabusa touched down on asteroid Itokawa? The answer to that question was unclear as we were assembling this week's show. We do know that the troubled but plucky little Japanese probe got close and may have even succeeded at collecting some bits of Itokawa. Even as scientists continue to analyze incredibly complex radar data from the European Space Agency's Mars Express orbiter, the spacecraft has switched from looking for subsurface water

to an examination of the Martian ionosphere. You can learn more about the status of its extended mission at planetary.org. The latest NASA Ambassador of Exploration got his moon rock last week. Wally Schirra, the only astronaut to fly Mercury, Gemini, and Apollo missions, was honored near his home in San Diego, California. Schirra commanded the Apollo 7 Earth orbiting mission. Later, he sat at Walter Cronkite's side as Apollo 11 landed on the moon. There was no announcement about whether Paul Haney is still a turtle.

Lights, camera, action. Emily Lakdawalla is back this week to explain how engineers take some of the most amazing movies in the history of rockets. I'll be back with Alan Stern in a minute. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, During the Apollo missions, they captured cool film footage of the Saturn rocket stage separations. How was this footage captured? stage separations. How was this footage captured? Some of the favorite images from the Apollo missions are video of the separation of the first and second stages of the Saturn V rocket, followed by ignition of the second stage rockets. These amazing images show the curving blue marble of Earth in the background. They were captured using 16-millimeter motion cameras mounted on

the forward end of the Saturn rocket's first stage. The cameras operated for less than 30 seconds as the rocket stages separated 80 kilometers above the Atlantic Ocean. After recording, the cameras were ejected from the rocket. They were enclosed in waterproof aluminum capsules equipped with para-balloons that slowed their descent and kept them afloat once they splashed down. After they fell into the ocean, radio beacons and dye markers helped the Air Force to locate them.

Nowadays, capturing film of rocket launches doesn't require such heroic efforts. Stay tuned to Planetary Radio to find out more. It was a long and difficult road getting this far, but we may now be less than two months from the launch of the fastest spacecraft in history. Speed is nice, especially since the target is distant Pluto, about six billion miles from Earth, as the interplanetary crow flies. Alan Stern is principal investigator for the New Horizons mission. He also serves as executive director of the Space Science and Engineering Division of the Southwest Research Institute in Boulder, Colorado. Not surprisingly, we found him making final preparations at the Kennedy Space Center. Before getting to New Horizons, I congratulated Alan on his discovery last summer

of two new moons of Pluto, so far known only as S-2005P1 and P2. Alan, welcome back to Planetary Radio. Sounds like your little spacecraft is going to have more to look at once it reaches Pluto. Yeah, it's the kind of problem we look forward to. Talk to us a little bit about this discovery of what certainly appears to be two moons, although I guess that's not fully confirmed yet to the satellite IAU. Right. A team led by Hal Weaver and myself

with seven other astronomers, planetary scientists, put in a proposal to the Hubble Space Telescope to look for additional satellites of Pluto. The proposal was eventually accepted. The observations took place last May, just a little over six months ago. Lo and behold, Hubble's an amazing tool. In eight minutes flat,

it discovered two new satellites of Pluto. Eight minutes? Eight minutes on the 15th of May, and it got them both, and eight minutes on the 18th of May and confirmed them. All right, and just as amazing to me is these things are tiny. Well, they're not so small, you know. The larger of the two could be as large as 100 miles across. They're small compared to Pluto, but they take you a while to walk across or drive across.

No, when I say tiny, I mean in relationship to how far away they are, that the Hubble was able to find these objects, and apparently very easily, at that kind of distance. I mean, we're getting pretty good at this. They're very faint, and they're next to something much brighter. Pluto is less than two arcseconds away and almost 10,000 times brighter. And you have every reason to believe that these objects are indeed moons because they're traveling along with Pluto, right? Right. I'll tell you what the evidence is.

We see them clocking around Pluto, unlike, for example, what you would expect a Kuiper belt object that just happened to be in the background, or an asteroid do, we make the assumption that they're in an orbit like Pluto's well-established moon, Charon's, that it's in the same orbital plane, that the orbits are circular. And when we plot where those orbits would fall, it goes right to the positions that we got in the HST data. Smack on. So then that leads us to believe they're probably real. We went back to old HST data of another team member, Mark Buies, from 2002. His data wasn't as sensitive, but lo and behold,

in the places where those orbits lie, there are little bright dots right on the orbit line, back in 2002, right where you'd expect. And at that point, we decided it was pretty close to checkmate. We should go public. You ever stop and think of Galileo as like a close personal colleague, suddenly realizing that these two little dots of light are gravitationally tied to a much bigger one? Matt, I have to say no. I never thought of Galileo as a personal colleague.

But I'm flattered. Thank you. You're welcome. It is certainly very significant and exciting to find these additional objects as we learn more about the Kuiper Belt that Pluto is on the edge of, of course. Are they going to tell us more about Pluto? I think they're going to tell us a lot more about the origin of the Pluto-Sharon system. For one thing, the satellites are caught in resonances, resonant orbits that have periods that are even number multiples of Sharons.

They're probably related to the Charon forming event. They're probably debris that got trapped in other orbits. Wow. It was a part of that event. We've learned a few other things about them. We'll learn a lot more. We're going to have more Hubble data in February, and then we're going to propose for time next year to do physical studies of them.

And I think they'll be a real boon for understanding more about the system. They also suggest to us, and this is very important to New Horizons, that Pluto may have rings. I had not heard that. That was completely unexpected. Well, the logic is pretty simple. We know that Pluto and Charon are out there in the shooting gallery of the Kuiper Belt,

and when things hit, they make craters. But for these two new satellites, they're small enough that the ejecta doesn't just fall back somewhere else on the satellite. It can get into orbit around Charon because they have almost no gravity. I mean, it can get into orbit around Pluto, so the debris would naturally form rings. So they're going to act like shepherd moons, possibly, as we're finding at Jupiter and elsewhere? They may. There's certainly likely to be source regions for rings.

Those rings would be very hard to find from the Earth, but they should be a cakewalk for New Horizons. I don't know why I put Jupiter ahead of, gave Jupiter top billing over Saturn and talk about rings, but what the heck, it's true there, too, I guess. You've called this region of space, this region of our very own solar system, the Kuiper Belt, a wild and woolly place, and apparently you're getting a lot of agreement from other scientists, entirely independent of your projects. No, I'm not surprised.

It's really the further out we go away from the sun, the grander and grander the exotica. You know, we've had Mike Brown from Caltech on recently, and he, of course, is, I would guess, as excited about you about what we may find out there, and he's finding some pretty big rocks himself. And he thinks that eventually we may just find, he's willing to put money on this, that we're going to find something Mars-sized out there. Well, that makes him about number 10 in line for that. 15 years ago, I was publishing papers in Icarus to just that effect, that we should find things Earth-sized, in fact. And there's pretty good smoking gun evidence as to why. When we return,

Alan Stern will give us a status report on New Horizons, departing for Pluto, its moons, and beyond in just a few weeks. This is Buzz Aldrin. When I walked on the moon, I knew it was just the beginning of humankind's great adventure in the solar system. That's why I'm a member of the Planetary Society, the world's largest space interest group. The Planetary Society is helping to explore Mars. We're tracking near-Earth asteroids and comets. We sponsor the search for life on other worlds, and we're building the first ever solar sail.

We didn't just build it. We attempted to put that first solar sail in orbit, and we're going to try again. You can read about all our exciting projects and get the latest space exploration news in depth at the Society's exciting and informative website, planetary.org. You can also preview our full-color magazine, The Planetary Report. It's just one of our many member benefits. Want to learn more? Call us at 1-877-PLANETS. That's toll-free, 1-877-752-6387.

The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. Our guest is Alan Stern, Executive Director of the Space Science and Engineering Division of the Southwest Research Institute, and Principal Investigator on the New Horizons mission to Pluto and the even more distant Kuiper Belt. I asked Alan to put this new spacecraft in the context of past planetary exploration missions. Well, New Horizons is a mission in the spirit of the original mariners and the pioneers in a Voyager mission.

It's the first time really since Voyager left in the late 1970s that we sent an expedition to reconnoiter a new planet. It is a flyby mission, but I think you and others have pointed out that you're going to actually have quite a bit of observation time as you reach Pluto. That's right, Matt. We specifically designed this to circumvent the criticism at the time that Pluto missions were struggling to get funded that, well, it's all for a weekend at Pluto. In fact, we have very sensitive instruments, long focal length cameras, etc., that will turn this into a five-month encounter with the Pluto system.

Using these instruments, you hope to reach Pluto, I guess. I mean, there was a lot of emphasis, particularly on the political side, that we needed to get this mission on its way before Pluto gets much farther away from the sun in its regular orbit. Are you going to get out there before the atmosphere is all frozen out? We're going to try. I can't promise you that, but we're sure going to try. No one knows when that atmospheric collapse will take place. There are some models that indicate it could take place while we're en route, and other models that indicate it could take place while we're en route, and other models that indicate it could be as much as 20 years away.

As we said, though, this mission is going to go much farther out. You plan to be getting data back from New Horizons for long past the Pluto encounter. Well, that's right. It's the Pluto-Kuiper Belt mission, and after our Pluto encounter, we will fire our engines and fly probably two to three years to reach a Kuiper Belt object, and after that, fly by. If we have the fuel and the spacecraft in good health, we'll fire the engines again and target a second Kuiper Belt system.

Do you have an idea of what object you're going to be going after, or is that going to be determined further along in the mission? No, much later. We don't need to pick those objects until literally the time of the Pluto encounter. And because we're learning so much every year, it would really be premature to pick now. I asked you what those new moons are going to tell us about Pluto. What is the Kuiper Belt going to tell us about the formation of our solar system, or what do you hope it might tell us? Well, it's going to tell us a lot about the early stages of planet formation, because

the Kuiper Belt is a region where planet formation initiated, and we grew from dust grains to boulders to mountain-sized objects to comet-sized objects, to comet-sized objects, to worldlets. In fact, most of the objects that we're interested in in the Kuiper Belt are technically called planetary embryos, objects that were on their way to planethood when something arrested their growth. We don't know what that may have been, but the important thing scientifically is this allows us to go back into those early stages of planetary gestation to study these objects the same way that a paleontologist would be excited about finding the fetus of a dinosaur.

Tell us about the current status of the mission. I guess you might have had a couple of scary moments there. It's been in the news that your upper stage, the centaur, that is actually going to kick New Horizons on its way, probably saying that it was in jeopardy is too strong, but it kind of got caught up in some labor difficulties at Boeing. Oh, let me tell you, all the hardware is down here at the Cape, the Atlas rocket, the spacecraft, the solid rocket boosters, the Centaur, the upper stage. The business with Boeing had nothing to do with the Centaur at all. It had to do with the solid rocket upper stage.

We have hundreds of people working on New Horizons, literally hundreds, to bring it to culmination with launch. I understand we have five workers that went on strike. We've worked through that. We brought in some people with a great deal of experience to replace those five, and we brought in some additional inspectors. So we're counting down to launch, and your launch window opens up in early January? It opens on the 11th of January, and we have a 35-day clock.

Of course, with every passing day, our ability to get to Pluto declines. The first 18 days, we can get there in nine years, and then Jupiter's not in as good a position after that. And then we can go in 10 years for a few days, and then 11 years for a few days, and then 12 years, so forth, until we run the clock out on the 14th of February. So we're very hopeful that we can launch in the beginning of the window. Well, we'll hope that exactly that happens on the 11th or very soon after. Nine years to get to Pluto seems like a real express.

It will be the fastest spacecraft ever launched, and by a long shot. I know when I was a boy, it was awe-inspiring to see Apollo astronauts lift off at 25,000 miles an hour and take three days to reach the moon. New Horizons will pass the orbit of the moon the same day that we launch. We take off at 2 in the afternoon, and later that same evening, before midnight, we will pass the moon. I'm sure you remember Galileo took six years to reach Jupiter, and Cassini took four. We'll do it in 13 months flat. It's really a screamer.

That's amazing. So it's not just your trajectory. You've just got a real good kick from this rocket. Well, we built the smallest spacecraft that we could get away with intentionally so that with the very large launch vehicle, the combination is ferocious. We get the speed to cross the entire solar system in record time. So let's say that you do get there in nine years. Sadly, you do have a little bit of a wait between now and then,

and you're going to keep busy doing lots of other stuff. Lots of other stuff and paying attention to New Horizons. Yeah, monitoring the spacecraft. Tell us a little bit about your responsibilities now as principal investigator as we head toward launch. Well, as you know, in the last couple of months, we're really just making sure that the spacecraft has finished all of its testing, same for the launch vehicle, and that we have all of our mission operations plans firmly in place

so that when we're out of the box, we're ready to fly it, we have a Jupiter encounter that's only a year away. That is amazing. Alan, you've got a lot of other stuff going on, I guess with maybe a minute left. I want to ask you about something much closer to home and much closer to the center of our solar system. You are still actively looking for vulcanoids between Mercury and the Sun. Well, we have a plan. We have a secret plan to go back and look for vulcanoids again in a couple years, and I expect there's a fair chance we might find them. I think it's a little bit like the satellites of Pluto, you know, persistence pays. I take it that being a

secret plan, you can't exactly talk about it on the radio? Not just yet. Okay, all right. Well, we knew that we'd be having you back soon enough anyway. Good luck. Hope things keep moving along smoothly there toward the opening of that launch window on January 11. We will definitely be back to talk to you about this, and it is an extremely exciting mission, and we will let people know that they can visit planetary.org, where you may, in fact, be listening to this radio program to learn more about the mission.

Of course, we'll also put up the link to the New Horizons site there as well. Matt, thanks for all your interest. Alan, thank you very much, and good luck. Dr. Alan Stern is now the Executive Director of the Space Science and Engineering Division at the Southwest Research Institute in Boulder, Colorado, but he is also the Principal Invest investigator for the New Horizons mission, lifting off soon, we hope, from Kennedy Space Center, headed for the outer reaches of the solar system. We'll be right back with Bruce&A.

How do we capture video from launching rockets? There is now a private company called Ecliptic Enterprises that is making a profitable business from putting cameras on launch vehicles. Ecliptic's rocket cams have been mounted to Delta IIs, IIIs, and IVs, to Atlas IIs, IIIs, and Vs, on Spaceship One, and on the Space Shuttle tank and solid rocket boosters. The cameras are tiny, weighing less than 100 grams, and can radio color images and even sound directly back to Earth as the rocket lifts off, or they can store the data for later download. The information that these cameras return as a routine part of space launches

will be of incalculable value in diagnosing the causes of launch vehicle mishaps. They will also give human watchers the vicarious thrill of soaring into space. Got a question about the universe? We also give human watchers the vicarious thrill of soaring into space. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Time for What's Up on Planetary Radio. We're joined by Dr. Bruce Fetz, the Director of Projects for the Planetary Society,

who's going to tell us all about what's up in the night sky and maybe some other stuff. How are you doing? I'm hungry. How are you doing? I'm hungry, too. People don't care, but what they do care about is that Mars is still beautiful. It has faded some. Hungry for the night sky. Oh, that's much better.. Hungry for the night sky. Oh, that's much better. They are hungry for the night sky.

They are hungry for Mars and its yellowish-orange spaghetti sauce type color. Okay, you really are hungry. All right. Mars rising in the, it'll be already up in the east after sunset, looking still very bright and orangish. And you will see it in the opposite side of the sky from where you can see Venus at the same time just after sunset. In the west, looking like an incredibly bright whitish star. Also Saturn rising later in the evening in the east-northeast.

And we've got Jupiter very low before dawn, very low in the east, southeast. We do have a meteor shower coming up in a couple weeks, depending on when you're listening to this. The Geminids will peak on December 14th, one of the best traditional meteor showers of the year, sometimes up to 40 to 60 meteors per hour. But it's near a full moon this year, so it's going to be tough to see. Still, you can go out there, stare at the sky, relax, and watch for meteors. We'll also have another meteor shower in early January that won't have a full moon. And you'll remind us of these.

Yeah, I'll check back on both of those. On to this week in space history. In 1971, Mars II became the first artificial object, at least made by humans, to hit Mars. To hit Mars. Yeah, it was supposed to, you know, land, but it did hit it. Yeah. So technically, score one for the Soviets. Yeah.

Random Space Fact! Now, I really worked on this one for you, Matt. Really? Yeah. Thank you. You said how much you enjoy this kind of thing, so I did my own playing around with some numbers. My appetite is whetted. Well, it was already, but go ahead.

I'm hungry. All right, all right. Well, if you're hungry, then if you picture yourself as a giant ball of food, that won't be helpful. Like, like. But. Okay. Okay. But if the sun

were as big in diameter as I am, so 6 feet, 1.82 meters. If I were just extending my arms and surrounded by sun, the earth would be about the diameter of a

U.S. penny. Wow. Or about a marble, the size of a marble. I see. You're right. I do love this stuff, common terms of measurement. When you put it in the bread box metaphor, I just love this stuff. Bread box is somewhere in between. But I've got more for you because how far away would you have to put that in our scale solar system?

Oh, wow. You'd have to put it over 200 yards away, over two football fields, no matter what kind of football you're playing. Let's do this after lunch. All right, I see what you're saying. We can move on. You sure you don't want to know how far the nearest star would be? No, no, no, that's what I'm saying.

We should do this after lunch. You'll be the sun, and I'll go out 200 yards. We'll put a penny down. All right. No, no, you'll be the nearest star because you'll have to go 33,000 miles away. Okay, I'm out of here. Bye. So basically, the nearest star at that scale would be really far away.

Space is big. I guess that was really my point. Okay, moving right along to the trivia question. We asked you how many parsecs in a light year. Trick question. Well, not really. I mean, it's a legitimate answer. Not if you bond with fractions or decimals.

That's right. Yes, it's different than people would normally ask you bond with fractions or decimals. That's right. Yes, it does. It's different than people would normally ask because that's the kind of people we are. We did have a couple of people who were disturbed by this because they knew quite accurately that there isn't more than one parsec in a light year. And they didn't want to think fractionally, I guess. But most people did. And we also got people who told us quite precisely, some out to like 12 decimal points, how many parsecs are in a light year. Should I tell you about our winner?

Oh, please do. It's Ian Chapman of Hertford in the United Kingdom. Ian, who got it right, 0.306 parsecs in a light year. Indeed, which means there's about 3.26 light years in a parsec. And we also had people who came up with rounded to.307, and, you know, come on, we're talking thousands here, so we're giving it to Ian and all the rest of you. If you had.306 or.307, you won too, but only Ian gets a Planetary Radio t-shirt. Congratulations. A parsec, by the way, short for the parallax of one arc second.

If you imagine the Earth kind of halfway around this, or one place relative to the sun, you go a quarter of the way around, so they're about an AU apart, astronomical unit, the average distance from the Earth to the sun, you go a quarter of the way around, so they're about an AU apart, astronomical unit, the average distance from the Earth to the sun. You create an angle from there going off into space to an object that is one parsec away. That angle will be one arc second. So anyway, this is the derivation of why people use parsecs, another term used in addition to light years when measuring things that are really far away. why people use parsecs, another term used in addition to light years when measuring things that are really far away.

I also want to thank the couple of people who wrote in with apologies for George Lucas and Star Wars and the Millennium Falcon, and one who even directed us to a website that explained why it's okay to say that the Millennium Falcon made the Kessel Run in 12 parsecs or less than 12 or something like that. And it actually is a pretty good rationalization to save George. Yeah, it's a tough thing. This is the issue we discussed where

they reference parsecs like it is not a unit of distance. And so, but they have this very strange, interesting rationale. Well, it's not that interesting, but it's strange. So anyway. It's only a movie. Oh yeah. We're going to get mailed from all the Star Wars people. I can't believe you just said It's only a movie. Oh yeah. We're going to get mail from all the Star Wars

people. I can't believe you just said it's only a movie. All right. Six movies. What do you want? Laugh it up, Furball. Moving right along. Next trivia question. Perhaps less controversial, but who knows? How many NASA flight directors have there been for human space flight missions in the history of the program? I don't know. Well, okay. You, along with everyone else, can look it up, or the NASA flight directors can contact us themselves. How many NASA flight directors have there been since the beginning of the program? It's for human space flight only, so these are the people controlling the human missions from the ground.

How do they enter? Go to planetary.org slash radio and find out how to enter and send us your information. And please, when you send your trivia contest information in, tell us where you listen to us. We'd appreciate it. Yeah, thank you to all of you who've been doing that. Get this one to us by Monday, November 28th at 2 p.m. Pacific time. Monday the 28th at 2 p.m. Pacific time. Monday the 28th at 2 p.m. Pacific time. All right, everybody.

Go out there, look up at the night sky, and think about lunch. Thank you, and good night. I'm way ahead of you. He's Dr. Bruce Betts, the Director of Projects for the Planetary Society. He joins us every week, usually just before lunch, on What's Up. Where will we take you next time? I don't know. It's a big universe. But we hope you'll come along for the ride.

And we may have an interesting announcement about our trivia contest. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week, everyone. Thank you.