Planetary Radio: Space Exploration, Astronomy and Science - MESSENGER Reveals Mercury

Episode Date: January 21, 2008

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MESSENGER REVEALS MERCURY 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. It happened exactly as planned. On January 14, the MESSENGER spacecraft made its first brief visit to our solar system's innermost planet. It showed us part of that world never before seen up close, and a few other parts that have changed little since they were viewed

by the Mariner 10 probe more than three decades ago. We've got two special reports for you, the first from our Bruce Betts, who was at the Applied Physics Lab in Maryland as the messenger team waited for word of success. Then we'll get Emily Lakdawalla's analysis of the spectacularly detailed images that have already been returned.

How can a beer can show us the way to affordable space travel? Our regular commentator Bill Nye the Science Guy has that answer in just a minute or so. And Bruce Betts will return to tell us where we should look for Mercury and its planetary sisters in tonight's sky, along with the new space trivia contest

and other goodies. It has been another busy week in our favorite universe where simply everything seems to happen. Get out your acronym notebooks. We've got a new entry for you. It's LCROSS, or L-C-R-O-S-S, NASA's Lunar Crater Observation and Sensing Satellite. LCROSS will launch later this year with the Lunar Reconnaissance Orbiter.

It will split in two, sending one piece to impact in one of the moon's permanently shaded polar craters. The other part of the spacecraft will then fly through the plume, kicked up by that deep impact, sniffing for water, hydrocarbons, and other good stuff, before it too smacks down on Luna. Just last week, the LCROSS science instruments were certified and packed off for integration with the rest of the probe. SOFIA has passed a major milestone on the way to becoming a flying observatory.

The Stratospheric Observatory for Infrared Astronomy is that specially modified 747 with a gigantic telescope where you and I normally sit. Test flights with the telescope door closed have been completed. Soon they'll start flying with that 16-foot hatch open to the sky. Lastly, this story from the creators of the Space Elevator Games. The Spaceward Foundation has upped the ante for the next Space Elevator Beam Power Challenge way, way up. Teams competing in September for an up to $2 million prize will have to send their light-powered climbers up a full kilometer on a tether suspended under a balloon.

We've got a link to the details at planetary.org slash radio. Back with Bruce's special report right after this week's visit with Bill Nye. Hey, hey, Bill Nye the Planetary Guy. You know, I'm vice president of the Planetary Society, and I'm very excited about doing this regular feature here on Planetary Radio. Today I'd like to talk about the beer can problem, or if you'd like, the soda can problem, the pop can problem. And that problem is roughly this. When you go take a trip in a conventional airliner, it's heavy, but 10% of that weight is fuel. 90% of the airplane is you and your luggage and some metal. But 10% is nothing but

kerosene with some don't freeze me additives. Well, if you want to do the same thing with some sort of future space plane where you take off from a runway, orbit the earth and then re-enter safely and land on a runway again, about 95% of that space plane would have to be fuel. That is to say, 95% of it is gas, with just 5% for you and your luggage and some electronics and keeping warm equipment and stuff like that. And this is why we call it the beer can problem, because a beer can is a soda can is maybe 95% liquid and 4% or 5% metal. This is a very, very difficult problem.

But the people who may address it are the space tourism advocates. People who are designing rockets with new materials, fabricated in new ways, way beyond or different from conventional aircraft aluminum and rivet construction. These people may make it possible for many of us to take trips into space for considerably less than the current price of about $20 million U.S. This could be a very exciting time when people everywhere get a view of the Earth from outer space. It may, dare I say it, my friends, change the world by changing the beer can problem.

Thanks for listening. Talk to you next time on Planetary Radio. Director of Projects. That's why he was in Maryland on Monday evening, January 14, celebrating with an international team at the Applied Physics Lab, or APL. I gave him a call minutes after the arrival of some very good news. Bruce, hello from California. Hello from Maryland. Can you hear me? Yes, indeed. Quite clearly, it's a miracle of technology. I am back here for the first spacecraft visit to Mercury in 33 years. That would be Messenger, as people who listen to the show a couple weeks would know. Planetary Society was co-hosting, along with the Applied Physics Laboratory, APL, co-hosting a public event with a lecture about Mercury, oddly enough, and Messenger and what's going on.

As we speak, the flyby was, what, maybe two, three hours ago? A little bit more, about six hours ago. That was the closest approach. That was when they were doing the burn, so you're right. They were still taking data three hours ago. So how did it go? Do we have some word about the success of this flyby? We know that the flyby, the trajectory part, was very successful. They plopped right about where they wanted to

plop in their trajectory correction that they were doing, getting a gravity assist, the first of three gravity assists from Mercury that will eventually lead them to where they can get into Mercury orbit in 2011. They've got a sunshade they need to keep pointed at the sun because that pesky Mercury being so close to the sun. They've got instruments they need to point at Mercury during the flyby, and it was just too much to also be able to point the high-gain antenna to Earth. So they're doing one of those flybys where they store all the science data,

and that will be coming back over the next couple days. But they were able to get the Doppler velocity data and see that the trajectory did what they wanted it to do. And so that much is wonderful. And soon, and by the time this airs, of course, everyone will know how it went in terms of the science data. So where were you during this? Were you there at APL? I was at APL, though it's more complicated than you or the listeners want to know. I was at other meetings in Washington, D.C. during the day talking about Earth observations, then came to APL shortly after the flyby and attended some receptions and some of the celebration part, and then participated in the public lecture where we had Sean Solomon,

the principal investigator of the mission, and then the main talk given by Bob Strom. Bob Strom, who holds the—he's the only person who was on the Mariner 10 team and now is on this team as well. Very interesting historical perspective. He even did a timeline of his life versus the timeline of trying to get Mercury missions. And also point out many of the weird things about Mercury. But of course, the thing, and I've mentioned it in other shows, but it's just so darn exciting. We haven't seen 55% of the Mercurian surface with a spacecraft. What they're going to get this time is about half the missing part.

And then the next flyby in this fall, they'll get the other half, the missing part. So the last chunk of a big planetary body that we've never seen. Plus they have really cool other instruments that will give us information that Mariner 10 could never give us. This public event that you were back there for, you said it was co-sponsored with APL? Yes, it was actually here in Laurel, Maryland, on the APL campus in one of their lecture halls. And Rob Strain, the head of their space department, also was one of the people announcing it. And so we had a good time working together with them and getting the inside scoop on what happened today and what they're expecting to happen over the next few days.

Let me ask you a question just about APL that I've been curious about because, of course, I've been to JPL, but I've never been back there. Is it the same kind of a place, or is it substantially smaller? Do you get a different feel from that facility? There's so much potential to offend people at one lab or the other. I think they're both wonderful. All right. They do give it a similar feel.

JPL's not on a hillside like JPL. It's flatter. But I think they're probably comparable in size. APL does a lot more classified and DOD work in addition to their planetary and Earth science and such than JPL does these days. So that's one difference. So you don't get an aerobic workout going to the farther reaches of the parking lot as you do at JPL? No. By the time you walk into the JPL gate, you're already exhausted. Yeah, I know.

So when are you headed back our way? I am headed back tomorrow and can hardly wait to come back to that lovely place. Well, and we will catch you, hopefully by the end of today's show, through the miracle of radio, for this week's edition of What's Up. You'll have all sorts of amazing miracles of radio on this show. Well, he is Bruce Betts, of course, the director of projects for the Planetary Society, back there representing the Society at this first flyby of Mercury in 33 years. And we wanted to catch him while he was still out there at the Applied Physics Laboratory,

operated by Johns Hopkins University. We're going to be back, though, in just a minute or so with Emily from a little bit later in the week. And hopefully she's going to have a report for us on some of the first science data returned by the Messenger spacecraft. This is Planetary Radio. Hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era. Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the P, B,

and J. The passion, beauty, and joy of space exploration. You probably do too, or you wouldn't be listening. Of course, you can do more than just listen. You can become part of the action, helping us fly solar sails, discover new planets, and search for extraterrestrial intelligence and life elsewhere in the universe.

Here's how to find out more. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. We just heard Bruce Betts reporting from the Applied Physics Lab as the Messenger spacecraft completed its first flyby of planet Mercury on January 14th.

The mission team got little more than confirmation of success on that first day. 100 hours later, they had much more to celebrate. Emily Lakdawalla's geology training often helps her in her work as the Planetary Society Science and Technology Coordinator, and it has proved useful once again as she examines and analyzes the beautiful images sent back by Messenger. I asked for her thoughts in a recent Skype conversation. Emily, it's been a few days now since the encounter. You've had some really excellent coverage of the data coming back,

some of your own work that you've done with those images. There are quite a few of them now, actually more than I thought we would see at this point. To me, the most dramatic, the most exciting is that spectacularly lit shot of this crater called Vivaldi. Do you agree? I agree that that one's one of the most striking. And I think it's just because of the way the light rakes across the surface. I don't think it really matters which crater on Mercury you were looking at. Just right on the Terminator there with the sunlight striking the edge of the inner ring of that double-ringed crater, just picking out all these little cliffs and mountain peaks, it's really gorgeous.

You were saying before we started recording that maybe at this point the real significance is that we got these at all. Absolutely. I think that the real significance of this flyby is that it seems to have demonstrated that Messenger works great. All of the instruments work great. They all operated quite happily with no anomalies through the flyby. The flyby was incredibly precisely targeted. So I think it just bodes very well for the future of the Messenger mission in general. It's like setting up your golf shot from Miami to Seattle and missing the target by less than two and a half inches.

It's pretty precise. Yeah. We get used to these golf analogies when they talk about navigation. shot from Miami to Seattle and missing the target by less than two and a half inches. It's pretty precise. We get used to these golf analogies when they talk about navigation. I think it's pretty amazing that they got within 1.4 kilometers of the altitude that they were aiming for. Also struck, of course, by the spectacular improvement in quality of these images over those taken 33 years ago by Mariner 10. Yeah, that's kind of funny. I was speaking with Clark Chapman, who has been working on Mariner 10 images almost since the Mariner 10 images were taken in 1974. And he said,

you know, in retrospect, I should have expected that they were going to look that much better, but I really didn't expect how beautiful that they were going to look. The quality is much higher. Mariner 10 had a television camera, and Mariner 10's targeting was very jittery, whereas Messenger's targeting is very, very precise, and the images are super sharp. Well, we've learned a few things in three decades. Maybe the most popular line in the popular media has been, gee, looks like the moon, But that can't be right. Well, you know, to be fair, it does look a lot like the moon. And that's no accident,

because there are a lot of similarities. They're both bodies with rocky surfaces that have no atmospheres. And that means that their craters look rather similar. Mercury is a little bit bigger than the moon, but not a lot. So the craters actually look very similar too, although they look a little shallower on Mercury than they do on the moon because of Mercury's higher surface gravity. So there are a lot of similarities. But as you start looking at things on Mercury more closely, you see differences too. I think two big differences that I see are that there are these ubiquitous faults crisscrossing the surface of Mercury that cut across craters. You see faults on the Moon as well, but they tend to be within

craters. You don't see them crossing the rims of craters in so many different places. Geologists saw these faults in Mariner 10 images, and they've interpreted them in the past to mean that the entire crust of Mercury has shrunk over time because the core shrunk as it cooled. But still, those faults are quite striking, and they're going to keep geologic mappers very busy throughout the MESSENGER mission and after. The other thing I noticed is there are these really interesting craters that have bright interiors but very dark rims. And you find them in several places in the images from Messenger,

but they're very concentrated in one large impact basin, which was partially seen by Mariner 10 called Caloris. And so those things seem to be speaking to some very interesting geology that's happening underneath the surface, and the impact craters have dug out different kinds of rock from beneath the surface than the rock that you see on the surface. Is it Caloris that you, at least in your blog, tried to do some matching between an image taken by Messenger

and one taken by Mariner 10? That's right, and it's a good example of how just a difference in lighting angle can make such a huge difference in being able to even find features on the surface of a planet. Mariner 10 saw Caloris on the Terminator, that is the day-night boundary. And as such, the light was coming at a very slanting angle like it is in the messenger image of Vivaldi. And so you could see picked out beautifully these multiple rings surrounding a huge impact basin, 1,300 kilometers in diameter.

But in the messenger images, Caloris is lit almost from straight above, and you cannot see those rims at all. The only way you can see Caloris is because of a slight brightness difference between it and the surrounding area. So a messenger is going to have to see the whole surface of Mercury at a variety of different lighting angles in order to be able to find all of the impact basins on the surface. And then it'll have to look at the same places with high sun in order to see how the the impact basins on the surface. And then it'll have to look at the same places with high sun in order to see how the surface brightness varies from place to place. Speaking of your blog, I want to share the addition you've made to my vocabulary with the audience.

And this was, I won't even try to pronounce it, R-U-P-E-S. Yeah, I usually pronounce it rupees, but I never really know how these things are pronounced. I just make a wild guess. And those are those faults that I was speaking about. They're very common across Mercury. Indicating that at least sometime in the past, this was a geologically active place. That's right. And it was geologically active after many of the craters formed on the surface.

You have to remember that most craters in a place that's as densely cratered as Mercury is and the moon, most of the craters that you see formed very early in the history of the solar system. Only some of them have formed in the last few billion years. Most of them formed in the first somewhere around four billion years ago, give or take a couple hundred million years. And so that faulting that we see that formed the rupees and the other faults, that happened after most of the cratering across the surface. You know that Mercury was geologically active for at least some couple hundred million years of its history. One thing that's kind of mysterious about Mercury is that you'd expect that that geologic activity would have halted a long time ago. But evidence suggests that it still has a molten core, at least a molten outer core,

because it has its own internally generated magnetic field. So there's actually a driver down there for continued geologic activity. So scientists don't necessarily expect it, but they would be delighted and somewhat surprised to see some evidence for much more recent geologic activity on Mercury. That's certainly one of the things they're going to be looking for. How long will we need to wait before the next encounter between Messenger and Mercury, and what will we be seeing that time? Well, the next encounter is coming up pretty soon in October. I don't know whether this is just a good fortune.

I expect it's mostly just a good fortune, but we're going to be seeing almost exactly the opposite face of Mercury than the one that Messenger saw this time. Because Mercury rotates so very slowly, on any one flyby, only one half of Mercury is sunlit throughout the whole flyby. So on this one, we only had a chance to see about half of the surface of Mercury, and Messenger wound up seeing slightly less than half of the surface. With the next flyby in October, we're going to see almost exactly the other half of it sunlit. So that's very fortunate.

Excellent. And not too long to wait either, October, that is. We are pretty much out of time, but I've got to ask you about your planetary scientist in training there, your daughter, Anahita, who had her own reaction to these images. That's right. The very first image that they released came out pretty late in the evening when I was getting ready to give her her dinner and put her to bed. And so I didn't have time to think about it very much, but she pointed to it and gave me her thoughts, which was, fall. Very astute observation. Emily, thanks so much. You're welcome. Nice to speak with you, Matt. We will, of course, put up links from where people may be listening to this show to both your blog and the article that you've just done.

And look forward to your return to Q&A next week. Emily Lachtwal is the Science and Technology Coordinator for the Planetary Society. And, of course, she is a regular contributor to this radio program with the question and answer segment. contributor to this radio program with the question and answer segment, and a geologist, which comes in very handy when you're talking about new features never before seen on the surface of the planet Mercury. We're going to hear a what's up segment, never before heard. That's when Bruce Betts will join us in just a moment or so here on Planetary Radio. It's time once again for What's Up on Planetary Radio. We are joined as if by magic by the Director of Projects for the Planetary Society, Dr. Bruce Betts. You were just in Maryland when last we heard from you.

Oh, wait a minute. Could you ask the executive director to please stop crunching chips into the microphone? Could you stop crunching chips in the microphone? Thank you, Lou. No offense, though. I love working here. Thank you. He's gone.

Yeah, he slammed the door. That was probably funnier visually. Welcome back from Maryland. Lou Friedman chewing. Great moments in planetary radio history. So, yeah, no, I'm excited to be back. And now I'm back, and we've been getting some Mercury data in, and it's fabulous. Yeah, yeah.

It's very cool. And we had a great event there. Overflow crowd came out to see me. Okay, they came out to see the main speaker Bob Strom and all the other people like Sean Solomon, but I was there. Sean Solomon, who will have to come back on the radio

show again sometime soon and tell us more about his spacecraft. He agreed to. He was a little concerned about talking to you again, but he was happy to come. No, just kidding. Alright, now I'm going to say, you called the head of APL the Grand Poobah. Technically the head of the APL Space Department. I called the Grand Poobah on the public event, yes. And he said he forgot his hat, his Poobah hat.

His hat, yeah. So hopefully that means I will be welcomed back to APL and not shot on sight. Anyway, we should probably tell people about the night sky. And conveniently enough, perhaps not coincidentally, Mercury is up. You can see it in the evening. It's always Mercury, a tough object. It never gets that far from the sun. But if you look for it above the west-southwest horizon, a little bit after sundown, you can see it. It looks like a bright star. So we've just got a festival of planets. Up higher, we've got Mars in the east in the early evening.

Actually, it's really just overhead in the evening. Saturn, Saturn coming up now around 8 or 9 p.m. in the east, and it will continue to get higher and rise earlier as we approach its opposition towards the end of February. In the pre-dawn sky, it's just getting exciting and crazy in the pre-dawn, that time period that I never see. Venus, brightest star-like object up, can't miss it in the east. But also now, if you look to its lower left, Jupiter starting to come up. And they will snuggle each other by February 1st.

Their conjunction only 0.6 degrees apart. Venus, Jupiter, two brightest planets up there. We're also going to have an annular solar eclipse coming up February 7th. We'll give you some more information about that. But if you happen to be in Antarctica or in New Zealand or eastern Australia for a partial solar eclipse, you can see that. I'm with you about that pre-dawn stuff. I think it's really just a nasty rumor that it even exists.

I do too, but I hear occasionally people are up. That's why I continue to mention it. I suppose if no one is, we could cut that part. Write to us if you were up in the pre-dawn and saw some of these things. Okay, good. See some of these things. On to this week in space history. A dark day in space exploration.

1967, Apollo 1 fire kills astronauts Grissom, Chaffee, and White. Happier news in the rest of this week in space history. 30 years ago, the first automatic resupply ship docking. Automated docking progress won. From the Soviets, 1986, Voyager 2 flew by Uranus. 2004, Opportunity landed, and it's still going strong. Already the fourth anniversary for that one on to random space

phobos moon of mars its orbit is degrading it will impact mars in about 100 million years. So careful where you buy land. All right, on to the trivia contest. We asked you about the robotic surveyor landers, soft landers, precursors to the Apollo human landings. How many legs did surveyor spacecraft have? How'd we do? You know, we got a tremendous response to this. It's the most entries I think we've ever had other than during the fifth anniversary contest period.

Maybe it's just because it was so easy. Because sadly, a lot of people obviously guessed. And they guessed wrong. They said four legs. Anyone say one? No, no, no. Well, you know, they did the extensive research on two, but it didn't work out. Oh, that's too bad.

Yeah, that would have saved some ass. So what's left? Three. Three and a half. Three plus or minus 0.5. We gave it to anyone who said that. Reminds me of a joke, but we'll leave that for another time. It's probably best.

We did get a winner, though. Somebody who was chosen first attempt by Random.Oregon. She had the right answer. It's Eleanor Frank of West Orange, New Jersey, who indeed said three legs had the Surveyor Landers. Now, there were people who said no and that I was wrong because I had put an upper limit at 12 legs. Lindsay Dawson said it was 15 legs because there were five successful landers. John Gallant went beyond that. He said no, it was 21 legs because there were five successful landers. John Gallant went beyond that. He said, no, it was 21 legs because there were two who crashed that crashed.

But, you know, the legs are still there. They're still on the moon. Clever. Haven't thought about cumulative legs. That'll be the basis of some future trivia, I'm sure. The best random space fact, though, came from Lieutenant Leonard Johnson. And he pointed out, reminded us, that Pete Conrad sawed – Had legs?

He did. And he used them to get over to Surveyor 1 because that was the Apollo mission that landed near the Surveyor. And he sawed its head off and brought it back to Earth. It was the first lunar decapitation. A pity to fool. I'm sorry. Mr. T walked through. I didn't think that was Lou.

Yeah, it's too bad. I believe that was not Surveyor 1. Oh, one of the other surveyors. Surveyor 3, I think. Oh, you're good. Well, I don't know. If I got it right, I'm good. We won't stop for that. People out there are either cheering me or laughing at me. As with most days of my life.

All right. We'll go on to a, you know, I think it's time to sink deeply back into bureaucracy. So our next trivia contest, answer the following. What are the names of the four NASA mission directorates? Now, this is tricky because NASA reorganizes about every two or three years. It's been a while, though, so you should find out the names of the four NASA mission directorates. Go to planetary.org slash radio. Find out how to enter.

Got till Monday, January 28, Monday the 28th at 2 p.m. Pacific time to get us that answer. And we're all done. All right, everybody. Go out there, look up at the night sky, and think about those little keys on telephones that you have to punch all the time and make those funny little noises. Thank you and good night.

Funny you should mention that because our phone at home, the buttons, you have to mash them. It's like an aerobic workout to call somebody nowadays. I wondered why your fingers seem to be bulking up. You like that? Yeah. Yeah, well, which is of no interest at all to the audience. So I'll just say that he's Dr. Bruce Betts, the Director of Projects for the Planetary Society, and he joins us every week here

for What's Up. Hey, let's go rotary. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Редактор субтитров А.Семкин Корректор А.Егорова