Planetary Radio: Space Exploration, Astronomy and Science - On the Way to Pluto with New Horizons Principal Investigator Alan Stern

Episode Date: February 20, 2006

Principal Investigator Alan Stern returns for the first time since launch of New Horizons toward Jupiter, Pluto and beyond.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Alan Stern goes to Pluto and beyond, 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. We've talked about New Horizons, the first ever mission to Pluto and its moons. This week, we hear from the source. Principal Investigator Alan Stern will give us an update on the probe and tell us what he'll be up to in the nine years it will take to reach the ninth planet. Let me tell you, he's a busy guy. Emily will tell us why it's not called the Voyager Anomaly in her space Q&A contribution.

And Bruce Betts gives us a surf and sky report on what's up as we give away another Explorer's Guide to Mars poster. At the top of our space headlines is a follow-up to last week's show about the proposed NASA budget. The agency is now getting some heat from Congress about its cutbacks in science and robotic exploration. The Republican and Democratic heads of the House Science Committee told NASA Administrator Mike Griffin that they were uncomfortable with the spending plans. As the next crew of Space Shuttle Discovery prepares for launch in May or sometime after, Florida Today has reported that one of the three remaining ships may become no more than an

organ donor in 2008. Apparently, NASA intends to cannibalize Atlantis, making it a source of spare parts for Discovery and Endeavor, which will complete the International Space Station on their own. You know we're always on the lookout for great pictures to share. Mars Rover Opportunity had already made movies of Mars moons Phobos and Deimos crossing in front of the sun. Now Europe's Mars Express has caught the shadow cast by Phobos on the surface of Mars. You can see them all in Emily's daily blog at planetary.org. And finally, NASA will be honoring the contributions of yet another individual with its Ambassador of Exploration Award. Not an astronaut this time, but someone who was nearly right there with them for decades.

Former CBS anchorman Walter Cronkite will be getting his little sliver of the moon in a ceremony later this month. If you followed space program coverage on TV in the 60s and 70s, you were probably watching Mr. Cronkite. It helped make him one of my heroes. Congratulations, Walter, and thanks. I'd say live long and prosper, but you have. Alan Stern of the New Horizons mission is just a minute away.

Here's Emily. a minute away. Here's Emily. Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, do the Voyager spacecraft also exhibit the Pioneer anomaly? In brief, we don't know. The Pioneer anomaly was discovered during routine tracking of the Pioneer 10 and 11 spacecraft, which are currently headed out of the solar system. Careful analysis of tracking data has shown that the Pioneers have not traveled as far as engineers predict. The engineers have gone back into the data and refined their models to try to account for the anomalous acceleration, but they have not been able to find any spacecraft-related force

that could be causing the slowing of the spacecraft. The inability to explain the acceleration using the laws of physics has raised the question of whether it's necessary to modify the laws of physics to explain the anomaly. However, it's still considered much more likely that some as-yet-undiscovered spacecraft process is causing the acceleration. So it's an excellent question to ask whether other interstellar spacecraft, such as the Voyagers, are also experiencing the Pioneer anomaly.

Unfortunately, it's impossible to answer that question. Stay tuned to Planetary Radio to find out why. Alan Stern is Executive Director of the Space Science and Engineering Division at the Southwest Research Institute in Boulder, Colorado. He's also Principal Investigator for the New Horizons mission, with a spacecraft that is right now racing through the solar system toward Pluto and the Kuiper Belt, with a stop at Jupiter just a year away. The mission was the result of many years of work, much of it taking place at the Johns Hopkins University Applied Physics Lab.

At times it appeared it might all be for naught, as NASA considered whether the mission should be kept alive. The successful effort has given Stern another reason to feel like a very fortunate man. Alan, while we have been talking about New Horizons, mentioning it at least, I think, every week since well before the launch, this is the first time since launch, the first chance we've had to say congratulations. Thanks, Matt. It feels great for the whole team. It's just fantastic to be in flight.

So as we speak, about a month in, and I guess things are going real well. You know, they really are. Sometimes I worry I'm going to wake up in this last month. It's just been a dream, and we're three days from launch. The spacecraft is very healthy. We're very far along in the spacecraft checkout. We did our early trajectory corrections that put us on the course to the keyhole at Jupiter. We have one more little cleanup burn

that will come in March, but it's literally 10 times smaller than the previous burn that we did. As I say, it's just a cleanup. And starting this week, starting in fact today, the 20th, we began instrument commissioning. Oh, that's great. And I heard that your data rate is a good deal better than you expected. Well, we're able to communicate. Of course, we're close to the earth now, but we're communicating at even higher rates on a routine basis than we'd planned for. And that's just a testament to what a fantastic telecom system APL built, and what a great job the DSN is doing. Could you say a little bit about what you and your folks there mean by Tom's cruise and Glenn's glide?

I see you've been reading. Yes. Yeah, absolutely. Well, when we first architected the mission for the Jupiter Gravity Assist, we named the period of time from right after launch until Jupiter Cruise 1, and we named the period from Jupiter to eight years all the way over to Pluto as Cruise 2, and those are a little dry, but we all knew what they meant. After a while, being devious, I thought I would try and honor my project manager,

who I knew would hate it, Tom Coughlin, and I started calling Cruise One Tom's Cruise because he had promised that he would stay with us to Jupiter. Well, it turns out he wasn't able to do that for health reasons, but he sure got us through design and confirmation and all the early startup phases and then handed it over to Glenn Felton, who became our project manager and took us through launch and will continue with us through Jupiter. In his honor, I've named Cruise 2 Glenn's Glide. And anybody who takes a look at the New Horizons website, of course, we will put that link

up on our website, planetary.org. But if you take a look at that, you'll see right up front, next to the PI's report, written by our guest, Alan, a color shot, a color drawing of the trajectory that divides this path up between Tom's cruise and Glenn's glide. You're, what, about a year away from that boost from Jupiter. Well, that's right. You can mark your calendars. It's February 28th, the last day of February next year. So a year from now, we will be in the thick of it with Jupiter observations.

And what, a little more than nine years from not your final destination, but the one that gets all the publicity, Pluto. Right, the Pluto system, Pluto and its cohort of satellites. Nine years from now, we will just be kicking off the distant encounter observations in the early part of 2015. And you were telling me before we started recording that something is going on, something that we'll be able to watch for, I guess, regarding the satellites of Pluto. Yeah, thanks for asking.

The nine of us, the team that Hal Weaver and I have led to search for and then find the two satellites of Pluto, received Director's Discretionary time from Matt Mountain at Space Telescope Institute, two orbits of Hubble's precious time, to follow up on the discovery, help refine the orbits, and search for additional satellites. Well, Pluto's come around the bend, out from behind the solar exclusion zone, and the first of those two orbits was executed last week on Wednesday, on the 15th, and the second one will come about 10 days from now.

And so in addition to refining the orbits, as I said, we may just have to see what Pluto provides. We may have something to say about whether there are additional satellites. But nothing you can talk about now, and in fact, you're just getting the data in. Right, right. And whatever we find, we'll want to confirm it with the second observation, whether it's thumbs up or thumbs down, it doesn't matter. To us, it's interesting. Right, right. And whatever we find, we'll want to confirm it with the second observation. Whether it's thumbs up or thumbs down, it doesn't matter.

To us, it's interesting. And from the standpoint of New Horizons, it's important to know what the list of targets is as we plan the encounter. And we'll cover that when that report comes out, of course, here on Planetary Radio. I got a question for you about this period between now and a few more years before you get up reasonably close to that Pluto system. That's the age-old question. What does a guy do to pass the time while he's on the way to Pluto? Well, a lot of people ask me that, and I sort of chuckle like I did

because I guess people think that Pluto is the only thing I work on. I'm a working researcher and working on a number of other different missions. I have an instrument on the Rosetta spacecraft headed to two asteroids and Mars flyby and a comet rendezvous. I'm a participant in both Mars Express and Venus Express on the science teams and becoming increasingly involved in Mars missions and future mission concepts. So I'm plenty busy. You don't have to worry. Now, I knew this, of course, because I know that you basically haven't slept in 17 years. Talk a little bit about that Rosetta mission,

which is, of course, one that has been in the works for many, many years. Rosetta is a phenomenal mission. You know, it's a Cassini-class, billion-dollar spacecraft en route for now for about two years to a comet with an almost impronounceable Russian name, Chermunov-Gerazimenko. We just call it CG, or sometimes Natasha for short. And the spacecraft's doing very well. There are 13 instruments, a small lander on board. Three of those instruments are U.S. instruments provided through an agreement between NASA and the European Space Agency,

since Rosetta is an ESA mission. And it will be the first comet orbiter to arrive at its target. It's the only one that's actually slated. NASA doesn't have current plans. We did have the craft mission many, many years ago, but it didn't actually end up getting built, unfortunately. So I think it's going to revolutionize our knowledge of comets by spending literally a thousand days with one, not just to fly by, but getting in and really seeing how it evolves as it goes through a perihelion passage day in and day out with everything from plasma sensors to infrared and ultraviolet spectroscopy to a phenomenal camera suite, and as I said, a lander.

What will be the nature of Rosetta's encounter with Mars? Well, as a matter of fact, Rosetta's going to be at Mars next year, and I can't decide if it's to my disappointment or to my delight because I have an instrument on Rosetta. The Rosetta-Mars flyby is the same week as the New Horizons-Jupiter flyby. Oh, man, never rains but it pours. There you go. So I guess it's the kind of problem you want.

But it's a flyby for a Mars gravity assist to turn the trajectory back towards Earth for a future Earth gravity assist that will come as we pump our orbit up over several years to match velocity with CG. And it's going to be a science-active encounter, so we're really looking forward to it, particularly for the ultraviolet team, which I lead, for the ALICE UV spectrometer, because this instrument has capabilities that no other ultraviolet spectrometer

at Mars has ever had. It's a new wave band, much shorter wavelength, and we expect to teach us a lot about the newly discovered aurora, the night glow, and something about the escape of Mars' ancient atmosphere. We'll hear more from New Horizons Principal Investigator Alan Stern after this break. 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, where we're talking with Alan Stern, Principal Investigator for the New Horizons Mission to the Pluto System and beyond. Before the break, Alan was telling us about some of the other things he's up to, including work with an ultraviolet instrument on the Rosetta asteroid mission.

But wait, there's more. Speaking of short wavelengths, talk to us about your instrument on the Lunar Reconnaissance Orbiter. Yeah, that's another derivative of the ALICE UV spectrometers on board New Horizons and Rosetta. It's called LAMP for the Lyman Alpha mapping project. It'll be the third ALICE-type instrument we launched, but because LRO only takes four days to get to its target, it'll be the first to arrive, while the other two are still in the mail, so to speak.

LRO has just passed its preliminary designer view, a big step forward, and looking forward to a launch at the very end of 2008. It'll arrive at the moon the week that it launches, actually just four days later, in our orbit. And our instrument, like some of the others, is about attacking the topic of, is there really water ice at the poles? We have circumstantial evidence for that. We know there's hydrogen excess, but we don't know if the hydrogen is bonded to oxygen as water.

Different instruments on LRO take different approaches. Ours can detect exposed water ice directly by using the Lyman Alpha SkyGlo that illuminates these permanently shattered regions only in the ultraviolet so that we literally see in the dark. Because they don't get any sunshine or earthshine. Right, but they do get Lyman Alpha Skyshine. And in addition, it's just a happy coincidence that there's a spectral fingerprint, a spectral absorption feature of water in the far ultraviolet,

so the combination of the illumination source from the stars and the interplanetary medium combined with that absorption feature allows us to look for exposed deposits of water ice, even if the water ice is only there mixed at a couple of percent in the regolith. We'll find it. We'll map it. We'll tell the landers where to go so they can set down and sample it. I'm still thinking of this contrast of getting to your goal in four days as opposed to getting there in 10 years.

But space exploration is a funny business. Let's get back to New Horizons, that long trip. New Horizons, other than visiting Jupiter, is going to stay busy along the way. In fact, I think you have something of a scoop for us. Yeah, well, as you know, we're going to hibernate most of the mission to save cost and to save time on our electronics. By the time we get to Pluto, the spacecraft will be nine years old, but many of the operating electronics will only be a couple years old because after Jupiter, we shut down and only wake up a little bit of time each year. So

that's a smart strategy APL put together. But during the wake-up, we'll be doing a little bit of cruise science each year. It keeps the team practiced, helps us check out our instruments, and as I say, it keeps us polished for the real deal at Pluto. And we've just announced something we found before launch and hoped that we'd be on the Jupiter trajectory. We will have a distant encounter with a centaur, an escapee from the Kuiper Belt, even before we reach Pluto. This will occur in early 2010. So distant, but I guess you still expect to get some good science out of this. Yeah, I don't think it'll be headline-making,

but nonetheless we'll be about six or seven times closer than the Earth would be. We'll be about 2.5, perhaps 2.8 AU away from the centaur, but it will allow us to make observations at both closer range and from special geometries, from angles that you could never get from the Earth as we pass by. And so I do expect some scientific papers to come out of it. And then we're going to continue to look, as new centaurs are discovered all the time, for the happy circumstance that one could be discovered even closer along our route of flight to Pluto. Well, you've gotten to exactly where I wanted to finish up with a couple of minutes left here,

and that is more KBOs, Kuiper Belt Objects. When you get beyond Pluto, we've actually had this come up on the show, but I'd like to hear from the source. How are you going to find and target these other possibly big objects out there in that belt after you've had the Pluto encounter? Well, we're going to find them, Matt, before the Pluto encounter because we need to make our maneuver as quickly as possible, meaning weeks, not months or years after Pluto. So we'll be searching for them with large ground-based telescopes that can go faint enough

to find the KBOs. The kind of KBOs we're looking for are ones that are 50, 30, 50, 100 kilometers across. Basically, what we think are the building blocks of objects like Pluto. We have done some mathematical studies, what are called Monte Carlo studies. We expect that within our reach, within the amount of fuel that we have, there could be anywhere from four to perhaps eight candidates. We want to find those and then select the best one or two for our trajectory. What is your Monte Carlo study, aptly named, tell you about the chances of finding something really big out there, on the order of the kinds of things that have been

showing up out there lately? Well, the larger they get, the fewer they are and the farther they are in between. So I'm afraid those odds are pretty low. If you get up around 100 kilometers, which is quite large, by the way, but nonetheless, not large as KBOs get since we're finding them as almost as big as Pluto. But even around 100 kilometers, the chance of getting a flyby would be quite low, probably 10 percent with our fuel budget. If you want to go for something 1,000 kilometers across, it's vanishingly small. And I can already tell you that there's nothing along that trajectory. But there is a very small chance for those who like to take chances that we could get very lucky.

Certainly, Providence has shined on new horizons so far. And eventually you join that royal family that emissaries from Earth, the Voyagers and the Pioneers. Right. Well, we'll be on out into the distant reaches of the solar system, although probably not operating after we leave the Kuiper Belt. I think if we do our job right, we will run the spacecraft out of fuel, visiting as many and as many interesting KBOs as we possibly can. We're not built to do deep interplanetary science.

We're built to do KBO flybys, and that's what that fuel's for. And we will continue to follow your progress as you head out there toward that Kuiper Belt and all the other wonders that are in store for New Horizons, and for that matter, the other missions that you're involved with, Alan. And I certainly hope that we can check in with you often before that encounter with the Pluto system. Matt, thanks for your interest, and also thanks for Planetary Society's support of getting New Horizons built. You are, of course, very welcome. Our guest on this edition of Planetary Radio has been Alan Stern,

principal investigator for the New Horizons mission, but someone with a hand in many other missions, all of which we will continue to cover here on Planetary Radio, right up to and probably beyond that wonderful encounter with Pluto, the Pluto system, that perhaps not most distant planet in our system, but certainly for our purposes or my purposes, very much a planet. And we will have other discoveries to make as we visit once again with Bruce Betts for this week's edition of What's Up.

That's right after a return visit from Emily. I'm Emily Lakdawalla back with Q&A. Do the Voyager spacecraft also exhibit the Pioneer anomaly? It's impossible to know because the Voyager spacecraft have a fundamental difference from the Pioneer spacecraft that swamps the tiny effect of the Pioneer anomaly. The Voyagers, like nearly all modern spacecraft, are three-axis stabilized. What that means is that the Voyagers maintain a constant attitude in three-dimensional space, with their x, y, and z axes always pointing in constant directions. In order to maintain this constant orientation against other forces acting inside and outside the spacecraft, the Voyagers occasionally fire tiny puffs of their thrusters to stabilize themselves.

The uncertainty in the Voyagers' ability to measure the force of their thruster firings is very small, but it is much larger than the tiny effect of the Pioneer anomaly. So even if it were affecting the Voyagers, we could not detect it. The Pioneer spacecraft, on the other hand, are spin-stabilized. They point at a constant direction in space by slowly rotating around one axis. They don't need thruster firings to maintain their attitudes. It is because of this spin-stabilization that it's possible to detect the tiny force of the Pioneer anomaly at all, making the Pioneer tracking dataset a unique and valuable resource.

Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Bruce Betts is on the line for this week's edition of What's Up? And we catch you today in San Diego, or more specifically, beautiful Coronado. Yes, indeedy-do. I'm doing some fluid dynamics studies and tidal studies, as well as studies of ultraviolet radiation and its effects on humans.

Surf's up, huh? Surf's up, dude! What else is up? Oh, there's seagulls, there's pelicans, there's all sorts of, oh, planets. I was thinking farther out there. Got it, okay. Well, I think I saw some F-18s flying by. All right, this is just getting annoying.

Let's move on to the night sky. In the night sky, we have high, high in the sky after sunset is Mars, still looking like a reasonably bright orangish star. And you can watch it as it continues to fade. It's kind of neat right now. It's right near the Pleiades, the cluster of seven stars. And so it makes for a pretty view, a pretty picture. You can also see Saturn in the evening sky rising.

It's already up fairways in the east just after sunset. It is below the bright stars Castor and Pollux, the twins of Gemini. You can also catch Jupiter rising in the middle of the night in the east and then basically almost overhead before dawn looking like an extremely bright star. Venus starting to be able to see that in the pre-dawn sky looking like an extremely bright star. Venus, starting to be able to see that in the pre-dawn sky, looking like an extremely bright star. And if you listen to this show soon after we record it, you can catch Mercury still in the evening sky.

I actually saw it last night. It is up and having a good time. As always, not that far off from the sun, so look just after sunset, and it will be a bright-looking star appearing off there in the west. So there you go. All five planets that you can see with your eye are up right now. Cool.

Moving on to this week in space history, February 20th marks the 20th anniversary of the Mir space station launch. So the Soviet Mir space station launched 20 years ago. Whatever happened to that thing? So the Soviet Mir space station launched 20 years ago. Whatever happened to that thing? It burned up in a fiery ball and took out a couple seagulls. Oh.

On to random space facts! I got really random and space facty this time. Infrared spectroscopy was able to identify the mystery material on Io as sulfur dioxide frost, particularly using which band? That's right, the strong 4.1 micron absorption band of sulfur dioxide frost. Boy, you were really randomized this time. Had we heard about this mystery component on Io? No, it's a 35-year-old mystery. Oh, okay. Okay, 25, excuse 35-year-old mystery. Oh, okay.

Okay, 25, excuse me. A Voyager mystery. A Voyager mystery, but it was solved actually with ground-based studies to figure out what this mystery feature was that no one expected when they expected to look out and see water ice like covering all the other satellites in the outer solar system. So there you go. Let's move on to the trivia contest, shall we? We asked you what was the giant storm half the size of Jupiter's red spot on Neptune,

Carl, that was discovered at the time of Voyager 2. How'd we do, Matt? Lots of entries this week. A lot of people, well, not really a lot, but a couple who were sad to see that this storm had disappeared, had a tear in their eye. And, in fact, Alex McDonald said, never forget. But Alex was not our winner. Our winner was Paul Kuzniar.

I think we pronounced his name correctly. Paul listens to the show in Poland, a city called, and I know I'm going to mangle this, Jelenia Gora. And Paul came up with the Great Dark Spot. May it rest in peace. Indeed, the Great Dark Spot. Rip? Did you have more on Neptunian spots, or shall I move on?

Well, we had a few other people who had things to say, like Paul Corman. He mentioned he wasn't thinking of the right storm, I guess. But I guess there was another one called Scooter? There was indeed, Scooter. It was a white spot that was moving rapidly around the planet, and it's been nicknamed Scooter, applied by the Voyager 2 team. The best name we got came from our friend, Reverend Brent, who said he wasn't sure. He said, was it Katrina?

And he said, no, I'm sorry, that was the one on Jupiter. No, not really. Those are different storms, smaller but worse. Yeah. Anyway, we don't have time to go into that right now. Let's move on to the next question, shall we? Speaking of nasty things on the Earth, in the state of Washington in the United States, what is the not-so-pretty name of the Mars analog areas where giant floods ripped up basalt thousands of years ago,

leaving scarred areas that have been given a pretty name, at least in my opinion? What is that name? Go to planetary.org slash radio to get us your answer. And when, what do we give them? Do a poster again? Sure, another beautiful Explorer's Guide to Mars poster. Those seem to be very popular. Indeed they do.

Hey, and everybody, don't forget, teaching that introduction to astronomy, planetary science class these days. If you're interested in watching it over the Internet, either live or delayed in the archives, you can go to planetary.org slash special, because it's very special, slash Betts class, B-E-T-T-S class. There you go. And here's something else that you don't want to forget.

Your contest entry for this coming one, the one just announced by our friend Bruce, you need to get that in to us by the 27th, Monday, February 27th at 2 p.m. Pacific time. February 27th, Monday, February 27th at 2 p.m. Pacific time. And we'll make sure that you get your shot at an Explorer's Guide to Mars poster. All right, Bruce, cowabunga. Cowabunga, dude. Hey, everybody, go out there, look up in the night sky, and think about the surf's up. Thank you, and good night.

He's Bruce Betts. He's out there shredding today, and he'll be back with us next week for another edition of What's Up here on Planetary Radio. And Planetary Radio is produced by the Planetary Society in Pasadena, California. Thanks for listening. We hope you'll be back next time. Have a great week, everyone. Thank you.