Planetary Radio: Space Exploration, Astronomy and Science - Countdown to Sample Return: A Stardust Special

Episode Date: January 2, 2006

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A little stardust is about to fall on Utah. We'll talk about it this week on Planetary Radio. Hi, everyone, and Happy New Year. Welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. Well, last July, the Deep Impact mission provided us our first look at the interior of a comet. And now, on January 15th, the Stardust mission will bring back to Earth

the very first sample collected from a comet. That's Andrew Dantzler, director of NASA's Solar System Division. He was first up at a recent press conference held in anticipation of an unprecedented event in space exploration. We'll devote most of today's show to that event, the return to Earth of a spaceship carrying particles dating back to our own origin in the universe. Not to worry, Bruce Betts will also drop by with a brand new space trivia contest in his pocket and stars and planets in his eyes. Emily is concentrating on the ears this week as she lets us listen in on a couple of cosmic metronomes. Here she is. I'll be back with lots more about Stardust in just a minute.

Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, how do scientists create sounds from data about stars and magnetic fields? As charged particles move around the magnetic fields of stars and planets, they generate radio emissions.

Many scientists study how the frequencies of these radio emissions vary with time in order to understand the changing nature of the magnetic field or to measure the rotation rates of giant planets and pulsars. These frequencies may be much lower or much higher than the human range of hearing, but it's easy for scientists to shift the frequency to a range that humans can hear, producing pretty bizarre sounds, like these from Cassini's recording of Saturn's kilometric radiation. Do these sounds represent anything real,

or are they just art made from science data? Stay tuned to Planetary Radio to find out. Back to NASA's Andrew Dantzler as he kicked off a Stardust media briefing at the space agency's Washington headquarters a few days ago. Dantzler looked back over his shoulder at a big picture of VILD-2, the comet visited by Stardust. Stardust flew through the dust cloud of one of those, survived, collected dust, and is on its way back home with that sample. At that Washington gathering with Andrew Dantzler were some of the leaders of the Stardust mission, including Principal Investigator Don Brownlee, a past guest on our program.

Don is obviously and understandably caught up in the drama and romance of a seven-year and nearly three-billion-mile round trip. We are ending, approaching the end of a quite fantastic voyage. Stardust has traveled further than anything else from Earth has ever traveled and come back. The Stardust mission traveled halfway to Jupiter to encounter a comet, grab a piece of it, and bring it back to the Earth. Where did this comet come from? This comet formed at the very edge of the solar system.

This is a view of our solar system 4.5 billion years ago at the time it was forming. You can see the center where the sun formed. You can see Jupiter in there and way at the very edge. That's where this comet came from. It formed out by Pluto at the very edge of this disk that formed the planetary system. That's where our comet formed from. It spent all of its lifetime out there until recently it came into the inner part of the solar system where we could sample it.

So we went halfway to Jupiter, but we were actually essentially going to the very edge of the solar system four and a half billion years ago, sampling the virtual building blocks that formed the solar system years ago. And these are literally the building blocks of our planetary system. Personally, I feel a strong attachment to this thing, and we should all feel a strong attachment to it, because the fact is all the atoms in our bodies, the carbon atoms and the oxygen and the nitrogen and the potassium and calcium and so forth, all those atoms were in Stardust grains, like are coming out of that comet now, before the solar system formed.

Yet Stardust has already returned valuable data about Comet VILD-2, much of it in the form of surprising images. We were stunned when we got to the comet and saw incredible features. We saw steep cliffs, actually overhanging cliffs. We saw spires and many features which, oddly enough, have never been seen on other solar system bodies. As exciting as that was, we're actually just using the comet as a carrier, as sort of a library that scarfed up the building blocks of the solar system,

preserved them far from the sun at low temperatures for four and a half billion years, and have now dumped them off. We grabbed them two years ago, and they're landing in the desert in just a couple of weeks. So how big are these bits of comet dust that are safely stored away in the Stardust return capsule? Even the biggest are what most of us would call, well, tiny. This is a particle that's less than the diameter of a human hair in size. And we will collect thousands or we will return thousands of particles like this. But this particle, for the analytical techniques that we use on them, is actually a giant rock, actually too big for us to analyze.

We slice them up into hundreds of slices. But we believe these samples that we collect will be themselves collections of tens to hundreds of thousands of very small grains. And the next slide shows one of the kinds of instruments that we will be analyzing. And when I say we, the preliminary examination team is people all over the world with all kinds of different instruments that will be analyzing these things at scales down to a single atomic scale. They will be analyzing specifically down to the size scales of the dimensions of our computer chips.

Don Brownlee also reminded us that his spacecraft is returning more than comet dust. Our mission is called Stardust, in part because we believe some of the particles from the comet will, in fact, be older than the sun and planets. They're formed around other stars. We call them Stardust. And believe it or not, these particles, even though they're small, are we consider huge giant rocks compared to our ability to analyze them because we're studying things literally at the atomic scale in some cases. There's a phenomenal amount of real estate in something even as small as a measly DNA molecule,

as you can imagine. Tom Duxbury is the Stardust Project Manager at the Jet Propulsion Laboratory near Pasadena. He provided a quick look at the mechanics of the January 15 sample return. As we're sitting here and talking and speaking, we have a world-class navigation team at JPL. They are positioning our spacecraft in space and time so that at late night, the 14th of January, we'll be at exactly the right place to separate our return capsule from our spacecraft. If we look at the first video, at four hours out from landing, and we will land about 3 in the morning mountain time, our return capsule

will be separated from our spacecraft. Our return capsule is only about 3 feet across, a little less than 3 feet across. It has a heat shield like the Apollo spacecraft did to survive the atmosphere. And we call this our knight in shining armor. If we look at the bottom part, it's protected by a very thick thermal heat protection system, and as we come in over the western United States, this thing will light up the night sky for a brief period of time, but buried inside of this capsule is our collector grid

that will contain the samples. If we look at the next video, we can trace the steps of this capsule coming over the western United States. Here it's seen over Nevada. It's ready to hit the upper atmosphere. And at this time, that from like San Francisco up to Portland, maybe even further, people can see this. Don Brownlee brought along a useful prop for his presentation. And this is basically what the collector looks like. It looks like a large ice cube tray filled full of this magic material called aerogel.

It's an ultra-low density silica glass. It's only a few times denser than air, and particles embed themselves into it and are captured. So our gift from the edge of the solar system, this is older than the solar system, in some cases older, will be contained in this grid, and a couple days after it lands, investigators from all over the world will be diligently digging into this, trying to reveal the secrets of our origin. Don Brownlee, principal investigator for the Stardust mission,

returning comet and star stuff to Earth on January 15, 2006. You're listening to the first Planetary Radio for that brand new year. We'll be back with more about Stardust, including a comparison to the Deep Impact mission, in just a minute. 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. I'm Matt Kaplan. We're preparing for the return of Stardust by listening to excerpts of a recent media briefing at NASA headquarters in Washington, D.C. Remember Genesis? That mission was similar to Stardust, at least in

that it returned a sample capsule to Earth. But the Genesis samples were wispy bits of the solar wind rather than comet dust. The Stardust team hopes there will be another difference. Genesis was supposed to be lowered more or less gently to Earth under parachutes. But those parachutes never opened. The sample capsule hit the ground hard, split open, and spilled some of its precious samples in the all-too-common dirt of the desert floor. Of course, the Genesis team has miraculously recovered some of those samples, and their near tragedy has been studied by their Stardust colleagues. Here's Mission Systems Manager Ed Hurst.

With capsules like this, in particular this one, this is the fastest return vehicle that has ever been brought back to Earth. So bringing it home for the first time is the only way to test a system like this. You do testing on the ground to the extent you can. So there is some residual risk that something could happen on return. We think the probability of that is very low at this point. By the way, when Ed says Stardust is coming in fast, he means fast. The sample return capsule will hit Earth's atmosphere at about 13 kilometers per second,

or 28,000 miles per hour. There is another mission worth contrasting with Stardust. We got a status report on deep impact from Jessica Sunshine just last week. Stardust principal investigator Don Brownlee was asked to compare that brilliantly successful trip to Comet Temple 1 with his own project. On Stardust, by having samples in the lab, we can look at this in a totally different way. Maybe a way to compare this is think of a human that you look at at a distance with a pair of binoculars,

and you can tell, wow, they're two meters high and hair on the top and two arms and legs and so forth. That's a certain level of characterization. But you get down to the molecular level, which you can do if you study from in the lab. You can study individual DNA and all kinds of details that you never dream of looking at if you're studying it by remote sensing techniques. So there's a lot of interplay between different missions. And deep impact and Stardust are highly complementary to each other.

And together they also form a phenomenal link between things that we can study in the solar system. In the solar system, we can go to bodies and study them directly. In the rest of the universe, we can't. We rely only on telescopic observations. So these two missions provide us an interesting link between what we can do here and what we can see out very far away outside the solar system. Someone who probably remembers the great old movie Andromeda Strain usually asks why the stardust scientists are so nonchalant about protecting us earthlings from those exotic samples.

Well, it turns out that they need protection from us much more than we need it from them, and for a very simple reason. Each year we have 30 to 40,000 tons of primitive material from comets and asteroids that lands on Earth, and this is about one particle per square meter per day. So during the course of our seven-year mission, there was more comet dust collected in your backyard than we're bringing home. So it's very natural. I mean, we have, you know, organisms on Earth have always lived surrounded by comet dust. We are also made out of materials like comet dust.

That's where we... Everything on Earth came from space. It took about seven-tenths of a billion years for life to show up on Earth. And when it first formed in here, the source of organic molecules that it assembled from were either made on Earth or they were delivered from space.

Now, they may not have been able to be made here. If that's true, they had to come from space. And the two sources we know of are bodies like comets and asteroids. Don and the rest of the Stardust science team expect to find about 2,000 larger particles in the aerogel collectors. That means particles that are a significant percentage of the width of a human hair. But they also expect there will literally be millions of much smaller comet crumbs and interstellar tidbits embedded there.

It may be enough to keep them and many other scientists busy for a very long time. Don points to the ongoing research based on material from the last sample return mission, one that took place 34 years ago. The last Apollo mission was 1972. And people are still discovering very exciting things on the Apollo samples. And the samples are a resource that's unending. So unless we consume all of the samples, they will certainly be studied decades from now.

My guess is there might not be a comet sample return mission in the next decade or so, so we're certainly it in the meantime. It's been a long time since the last return of solid... I mean, the Genesis mission returned solar wind from space, but this is the first return of solid samples from space since Apollo 17 in 1972. It's only Stardust's 101-pound sample return capsule that is returning to Earth. The rest of the sizable spacecraft, the so-called bus, will remain in space,

passing our planet periodically as it circles the sun. Don and his colleagues are finding fulfillment even in space, passing our planet periodically as it circles the sun. Don and his colleagues are finding fulfillment even in this, because stardust still carries an important cargo. The importance may be more symbolic than scientifically useful, but it nevertheless carries personal significance for a lot of people. It'll either collide with a planet or the sun or be ejected from the solar system. It's most likely it will be ejected from the solar system. And we have a crew on board of over a million people that signed up

and their names are etched on a little silicon chip. And as an astrobiology type person, I'm intrigued by the thought that those names in that spacecraft will far outlive the Earth. When the sun becomes a red giant and scorches Earth, that spacecraft and those names will still be floating around the galaxy somewhere. We've been listening to excerpts from a recent press conference at NASA headquarters in Washington, D.C. The briefing featured Andy Dantzler, Director of NASA's Solar System Division, Ed Hurst, Mission Systems Manager,

Tom Duxbury, Stardust Project Manager, and Don Brownlee, Principal Investigator for the mission. Planetary Radio will offer continuing coverage of Stardust. We'll do our best to bring you the highlights from its return to Earth in the early morning of January 15. Check your radio volume. Emily is coming back with more sounds from space. This one is a bit less eerie, but more like the cosmic metronome I teased you about earlier.

Then we'll join Bruce Betts for a what's-up look at the night sky and the triumphant return of the Space Trivia Contest. Stay with us. Thank you. I'm Emily Lakdawalla, back with Q&A. When scientists make sounds from radio emission data, do the sounds represent anything real, or is it just a form of art? All of these so-called sounds are created from electromagnetic radiation that propagates through a vacuum, something sound cannot do. So these scientists created sounds do not in fact represent any real sounds being broadcast through space. However, converting the radio data to sound

is a way of permitting us humans to use our sound processing brain power to help us observe what is going on in the radio emission data. With our ears, we can detect and analyze patterns in the sounds that may not be immediately obvious within the numerical data, like the beating of the rapid rotation of a distant pulsar. a distant pulsar. Got a question about the universe? Send it to us at planetaryradioatplanetary.org. And now here's Matt with more Planetary Radio. It's a new year.

Time to begin a new year of What's Up? with Dr. Bruce Betts, the Director of Projects for the Planetary Society. Bruce, hope you had a great new year, or you're still having it. I'm still having a great new year, Matt. How about you? So far, so good. So far, very much enjoying it. Had a wonderful holiday.

And looking forward to looking at the night sky. As well you should. As well you should. As well you should. Go look at the night sky. And, of course, in the evening you can see three planets, Venus, Mars, and Saturn. Venus low in the west, getting lower, lower, lower, but still looking like an extremely bright star. See Mars in the south, dimming, dimming, dimming, but still looking like a pretty bright star in orange.

And Saturn looking like a kind of bright star, but with those groovy rings. If you take a look through a small telescope, and it is rising a little before about 7, 7, 8 p.m. Getting easier. Getting easier and below Castor and Pollux and the two bright stars in Gemini. And let's move on to this week in space history. On January 4th, January 4th. Now, this is less space history than space now,

although it happens every year. Earth will be at perihelion, its closest point in its orbit to the sun. And that happens every January. It's January 4th. And we'll come back to that, perhaps in the trivia contest. Ah, a clue, a hint. A hint, a clue.

We like to call it foreshadowing. A precursor. A precursor. A tease, a tag, something. You win. Okay. Yay. Let's move on to...

Red Light, Space Fact! Recall-o! No. No, maybe you don't. But let's tell you, this one's kind of obvious, but not everyone thinks about these things all the time. But secondary impacts, this is when you get a big impact into a planetary surface. Stuff gets thrown out, falls back down, makes all secondary impact craters. Most of it.

Yeah. Most of what? Most of the stuff falls back down. I mean, on Mars, some of it comes to Earth. Well, yeah, but we're not talking about that part. You're only talking about secondary impacts. I'm talking about secondary impacts on the planet right now. I'm sorry I stepped all over you.

Go ahead. All right. Well, okay. After that. I destroyed your pacing. I'm really sorry. Okay. I know I'm lost for the rest of the show.

Maybe I'll just do a different one. I don't feel like that one anymore. Really? Seriously? No. Move on. Okay. Secondary impacts.

It's your segment. Really? No. No. Well, it's really your segment. No, it's your segment. All right. Well. You're the director of projects. That's true. Move on. Okay. Secondary impacts. It's your segment. Really? No, no. Well, it's really your segment. No, it's your segment. All right. Well, you're the director of projects.

That's true. I am. All right. In that case, secondary impacts. I wanted to point out that on more massive bodies, higher gravity, really, it's not the mass. It's the surface gravity. Like Mercury, say, compared to the moon, they fall closer to the impact, the primary impact. Why do I mention this?

Because if you stare enough with the trained eye at impacts on Mercury and on the moon, of course, with the untrained eye and just looking initially, they all look very similar. But you'll start to see differences. And one of them on Mercury is that secondary impacts will fall closer to the tree. Well, my jaw has dropped. I've been looking at the moon through telescopes for decades, and now I'm going to go out and check it out. Do that and then compare it to some pictures of Mercury.

Okay. Yeah, you'll also see slightly different crater formation. You'll see that different diameter craters go to central peaks at different sizes, all sorts of interesting subtleties of craters. It only makes sense. I just wanted to open that chapter to the world. And now let's open another chapter by going on to the trivia contest. Goody. We asked you, how big is an AU, an astronomical unit? This is the average distance between the Earth and the sun. How'd we do?

Tons of correct answers. We even got some that provided additional details, like Connor Hanrahan. Not our winner. Sorry, Connor. But he said that the number he came up with in meters is accurate, scientists say, to about plus or minus 30 meters. That's pretty good. But here's our winner. And I've been waiting for this one because he's entered quite a few times. And I don't think he's won before.

Igor Popov. Igor Popov, who is from, okay, bear with me here, Novosibirsk in Russia. And he got it right, too. 149,597,850. No, wait a minute. That's wrong. 150 million kilometers or 93 million miles. There you go. Igor,807. No, wait a minute. That's wrong. 150 million kilometers or 93 million miles. There you go.

Igor, you won. We're going to send you a T-shirt. Congratulations, Igor. He put Igor. He said Igor. I thought it was Igor, but he put Igor for his pronunciation. I'm sure he is correct, and I apologize for my mispronunciation. But at least you pronounced the name of the city correctly.

Yeah, right. Who's going to know other than Igor, R-E-G-O-R? Let's call the whole thing off. All right, to tie together, you're going to love this. I tie together that trivia question and my This Week in Space history. Love it when it all comes together. It's all coming together, folks. my This Week in Space history.

Love it when it all comes together. It's all coming together, folks. I ask you, how close is Earth's perihelion to the sun? How far are we from the sun, from the center of the sun? Yeah. In AU, in astronomical units, give it to me to at least two decimal places, how close is perihelion? So how far off are we from the average 1 AU? Oh, I love it. It's so integrated. This is great. Okay. Yeah? So how far off are we from the average 1 AU? Oh, I love it.

It's so integrated. This is great. Okay. Yeah. So how do they enter? I don't know. Oh, right. Go to planetary.org slash radio.

Find out how to integrate yourself into our contest and win a fabulous prize. And be sure to become integral by Monday, January 9th. Monday, the 9th of January at 2 p.m. Pacific time. And we'll make sure that you're entered in this contest. So remember, don't enter just to the nearest integer, because that would not be integral. All right, that was ridiculous. Okay, how about everybody go out there, look up at the night sky, and think about whether magnets would stick to your brain. Thank you, and good night.

It wasn't that much of a reach. I liked it. Integers, integers, integers, igor. He's Bruce Fetz. He's the director of projects for the Planetary Society. He's here every week with a magnetic personality for WhatsApp. We've got an extra minute to do something I've never done, which is to thank some of the other people who help make this program possible each week.

You know about Bruce and Emily, of course, but that's because you get the pleasure of hearing them. How about Monica Lopez, the Planetary Society's Marketing Director and Webmaster, and Brandon Schultz, our Network Administrator. You've actually heard Jennifer Vaughn, our Director of publications, but I won't tell you how. She also serves as our most constructive critic. And Charlene Anderson, associate director of the Planetary Society, who helped get this program started. The news stories I often refer you to, and upon which I also rely,

are usually written by my colleagues Amir Alexander, AJSJ.S. Rail, and, yes, Emily Lakdawalla. Susan Lendrith helps get the word out, Lou Coffey makes sure everything gets paid for, and Andrea Carroll digs up the dollars Lou uses to pay for everything. Thanks also to the rest of the Planetary Society staff, to all of our wonderful guests, and most especially to you, dear listeners. There wouldn't be much point if you weren't along for the ride. Your support means a lot to us.

It's vacation week, so we'll be doing something we haven't done in a year and a half. That's presenting you with an encore edition of the show next time. If you missed our star-studded Planetary Society 25th anniversary celebration, your second chance arrives in seven days. I'll be back with a brand new show the following week. Take care, and once again, Happy New Year. Thank you.