Planetary Radio: Space Exploration, Astronomy and Science - Flying the Skies of Saturn’s Moon Titan

Episode Date: January 16, 2019

Imagine soaring over what may be the solar system’s most Earth-like world, if you ignore the chill. If funded, the nuclear electric-powered Dragonfly will do exactly this. Principal Investigator Elizabeth “Zibi” Turtle shares her enthusiasm. Emily Lakdawalla reports on Chang’e 4, China’s pioneering lander and rover on the far side of the Moon.  Bruce and Mat answer a question that had no answer till New Horizons flew by Ultima Thule days ago. That’s part of this week’s What’s Up. Learn more at:  http://www.planetary.org/multimedia/planetary-radio/show/2019/0116-2019-elizabeth-turtle-dragonfly-clipper.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

A flying machine for Saturn's moon, Titan, this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. They call it Dragonfly, and there has never been anything like it. Will it get the chance to fly across the frigid yet surprisingly Earth-like surface of Saturn's moon? We'll learn more from the project's principal investigator, Elizabeth Zibby-Turtle. It was a question no one could answer when Bruce Betts asked it two weeks ago. Now we're ready to resolve that space trivia contest quiz about New Horizons' recently visited target.

The Planetary Society's Jason Davis is keeping up with China's great success on the far side of the moon. You can read his work in the Planetary Society blog at planetary.org. Jason's colleague, Senior Editor Emily Lakdawalla, is also on top of this mission. I talked with her at Planetary Society headquarters a few days ago. I passed by your office a little bit earlier today, and there you were working away at Photoshop, creating something which is now available to everybody online, and it's pretty terrific. We have some really amazing video from China showing the descent of the lander Chang'e 4 to the surface on the lunar far side. And then even better for me, the deployment of the rover, its little wheels

rolling out onto these tracks, the tracks being lowered like a forklift to the lunar surface. And then just instantly, the rover drives right off, leaving tracks in the very powdery dust of the lunar surface. It's just amazing. I guess you tweeted it out, but our colleague Jason, who has been writing regularly about Chang'e 4, he'll be blogging about this? He already has. You know, there's been so much space stuff going on in the last couple of weeks. Jason and I have been working on each other's stuff. We've got the Chang'e 4 landing. We've got the OSIRIS-REx going into orbit, the MU69 flyby.

It's just been overwhelming in a good way, but I'm also kind of tired. Well, and you didn't mention InSight, but you have written about it because InSight is just going great guns. When we had that wonderful live launch event, it sounded like it was going to be a lot longer before the real science started to come back, but I guess they're pretty close. They're very close. We're definitely not quite at real science yet. They still have to do some things like putting the very important wind and thermal shield over their instrument to keep it protected from changes in temperature and, yes, Martian wind that would upset the delicate balance of the seismometer. But the instruments have gotten back their first data, and it's looking spectacular. The scientists are so happy. Any word about when they will start drilling down below the surface? That'll happen probably late February.

They'll start doing that. It's not exactly a drill, remember. It's a self-hammering mole that kind of just pings its way down. It's going to be kind of fun. So much going on, as you said. It's a big time for planetary exploration. It really is. And it's just a pleasure to have so many international collaborators. I'm on Twitter and I see, you know, at the end of my day, Japan and Australia are waking up overnight. I see Europe come online. And just as the world turns, we have data coming in from agencies all over the world, and it's a great time.

Thanks, Emily. Thank you, Matt. That's Emily Lakdawalla, Senior Editor for the Planetary Society, and part of that means that she's in charge of the Planetary Report, which you can now check out online. The whole magazine is there in a great online format, and see what's happening all over the solar system as well as the terrific writing that goes into that magazine each month. We'll talk to her again soon. In 2020, the next Mars rover from the U.S. will carry a flying machine to the red planet. This tiny helicopter will mostly be a proof of concept. A far more ambitious cousin is being planned at the Johns Hopkins University Applied Physics Lab.

If it is funded and successfully reaches Saturn's cloud-shrouded moon Titan, Dragonfly will allow us to explore far more of this tantalizing world than a rover could hope to cover. One of the highlights of my recent visit to APL was the chance to sit down with the leader of the Dragonfly effort, Elizabeth Turtle Goes by Zibi, a nickname she picked up as a toddler when she couldn't quite say Elizabeth. Zibi has joined us a couple of times previously, but this is her first visit as principal investigator

for both Dragonfly and the camera system that will be aboard the Europa Clipper spacecraft when it leaves for that other moon in the early to mid-2020s. Zivi, Elizabeth, welcome back to Planetary Radio. Thanks very much. It's a pleasure to be here again. And nice to be doing it for the first time face-to-face, thanks to the fact that I'm here to cover this wonderful mission, this encounter with Ultima Thule. But I'm getting all this other wonderful material, which I guess is just terrific evidence of all the great things happening here at APL.

Yeah, there are a lot of exciting things going on, and especially, as you mentioned, with the New Horizons flyby of Ultima Thule. That's been really exciting, and we're anxious to see what they get. As we speak, we are only about three hours away from seeing the latest and greatest that has been sent back by the spacecraft. So are you going to be in the room again looking for that new higher res image? I hope so. I hope so. It'll be very interesting to see what they see out there in the far reaches of the solar system. Yeah, can't wait. But you're a busy person. You have a lot going on. And we're going to talk about just a couple of those things that are keeping you busy right now.

Beginning with the one, and I've been trying to think of how to talk about this, because everybody that I know, myself included, is so excited about this mission that is still just a candidate that is waiting to see if it's going to be funded. And you know, we're the Planetary Society. Every mission that reaches this stage that Dragonfly has reached, we would love to see get out there into the solar system. But there certainly is something especially captivating about sending a flying machine to this absolutely stunning world of Titan. I don't think you'll disagree. No, I won't. There are certainly a lot of important places in the solar system to explore. And we're very excited to be at this stage

in the proposal process for New Frontiers and to be able to work on the Dragonfly mission at this point. There's a lot of work that's been done in the Phase A study that we're just completing, and we're really hoping to be able to get back to Titan. You said it's a New Horizons mission. Excuse me. New Frontiers mission. New Horizons was the first spacecraft in that class. And this is because it's cheaper than one of the most expensive missions.

I mean, things like Curiosity or the James Webb Space Telescope. Right, or Europa Clipper, the flagship, or Cassini, the flagship class missions. Right. New Frontiers is the next step. So the mid-range. It's the mid-range. It's the next step up from Discovery. With the Discovery missions down at the lower level. Yeah. Still big investments, of course, and so we would expect NASA to do a great job of evaluating these. How do you make the case for Dragonfly? I mean, of course, one of the things that we know from past experiences that NASA likes to go with proven technologies that seem safer because they have worked in the past. And Dragonfly is pretty

innovative. It is. It's an innovative application of existing technology. And that's really what we've leveraged here in developing the mission concept. Dragonfly would send a rotorcraft lander to Titan, spend most of its time on the surface making science measurements, but it would be able to fly from place to place so that we can get to multiple sites to make those measurements. It is an innovative exploration strategy, but the technology that we use to do that is all technology that exists and has been proven here on Earth or on Mars. And so we're able to leverage that and take advantage of the technological advances that have already been done and then apply those to Titan exploration. Other than calling it by the mission name Dragonfly, how do you describe this device, this flying machine? I mean, I have heard people call it a quadcopter, but it's really double that. It's really an octocopter.

That gives people the sense that it's got eight arms and it's actually got four arms with two rotors on each. So technically it's an X-8 rotorcraft, but sometimes we'll call it a dual quadcopter or mostly we refer to it as a rotorcraft lander. So you'll forgive me because when I first heard about this, I thought, okay, I know drones. I got one for my birthday a couple of years ago. They're little tiny guys. And it's only very recently that I've learned how big this craft is going to be. Give us an idea of its dimensions. It's a similar size to a Mars rover. We have a similar type payload. We have four instruments. Now, do you mean like Spirit and Opportunity class or more like Curiosity?

Like Spirit and Opportunity class or more like Curiosity? It stands a little over a meter high, a couple meters across. Yeah. So it's a, I mean, it's a, yeah, it's somewhere in the mix of the lander sizes. So it is much larger than the drones that one is used to playing with in one's backyard. It carries everything with it, like the Mars rovers. So we have a MMRTG power source. So it's a radioisotope thermal generator, the same thing that's on the rear end of Curiosity. Right, yeah.

Exactly. And so we have that and the payload, and everything comes with us. It's a single unit that moves from place to place. So this is not going to be a light spacecraft, at least in terms of its earth weight, because, I mean, you've got the RTG, that's got a lot of shielding, you've got all these instruments, but you can get away with this on Titan apparently, right? Right. The gravity on Titan is about a seventh of the gravity here on Earth. The other thing that makes aerial exploration such a possibility on Titan, of course, is its atmosphere.

And the atmospheric pressure at the surface of Titan is one and a half times that at the surface of Earth. So it's actually easier to fly on Titan than it is on Earth. I have heard people saying that a human, properly insulated, could fly on Titan. You'd just flap your arms with the right wings attached. Yes, if you had wings and a good sweater, you'd be able to fly on Titan. You ever read the great Robert Heinlein story? I think it was called The Menace from Earth. And there are big lava tube type cavities on the moon.

And people are flying around on the moon doing exactly this. Something to think about for the distant future, I suppose. But for now, this idea of a flying machine, as I called it on Titan, the answer to this is probably obvious. But why will it be so useful to be able to do more than just crawl across the surface as we do on Mars? So we know from the Cassini observations of Titan that it has a very varied geography. Titan is actually surprisingly Earth-like. It has, with the atmosphere, it has a lot of atmosphere-surface interactions.

There are sand dunes, except it's organic sand. There's actually a methane cycle, like our water cycle here on Earth. And so there are methane clouds and methane rivers and wide distribution of types of material on the surface. And what we want to be able to do is get to different places to be able to understand the chemistry of Titan in these different environments. Because this is fundamentally a mission to understand prebiotic chemistry. fundamentally a mission to understand prebiotic chemistry. And so we want to be able to understand how materials have interacted, how chemical compounds have interacted in different places on Titan where the history has been different. So to be able to get to areas that are tens or hundreds of kilometers apart, we really need to be able to use this technology to fly. It gives us

just a much longer range to be able to travel. You said you're going to be looking to use this technology to fly. It gives us just a much longer range to be able to travel. You said you're going to be looking for prebiotic conditions. Maybe I'll ask first how your instruments will do this. So maybe talk about the instruments that you plan to carry. Right. There are four instruments that Dragonfly would carry. One is the mass spectrometer. This is a mass spectrometer very similar to the SAM instrument that is on Mars right now. On Curiosity, right? Absolutely. So this is one of the applications of current technology to the Titan environment. So we would be able to sample material from the surface into the mass spectrometer to measure details of the chemical composition. And this is

one of the reasons we want to be able to go to different places is to see how the chemistry differs from place to place on the surface. So will you have a scoop or a drill? Drills, yep. And we can use pneumatic transfer because we have an atmosphere. Ah, so you'll just, like pneumatic tubes in old department stores or bank branches. Exactly. Yes. Yeah, right. Fascinating. Okay. Which also makes me think of PlanetVac, the technology that the Planetary Society has been supporting development of. Yes. And I believe for that you're working with Honeybee Robotics. We sure are. It's their concept.

And that's the same team we're working with on Dragonfly. How cool. I did not know that that had come up. All right. Another check for the Planetary Society there. What other instruments? There's a gamma-ray and neutron spectrometer. This allows us to measure the bulk elemental composition in the area under the rotorcraft. It's complementary to the mass spectrometer, which will measure very detailed chemistry of specific sites.

We get a different sense of the material components available for that chemistry with the gamma-ray neutron spectrometer. an instrument that's been used on other spacecraft like the Messenger spacecraft and the Gamma Ray Neutron Spectrometer is also being developed for the Psyche mission that's in development for Discovery. But one of the differences for Titan is that because we have an atmosphere that shields the surface from cosmic rays, so we actually have to bring a neutron generator with us so that we can generate neutrons to be able to sense the products of those reactions. Because at asteroids, it's the cosmic ray impacts that give you those,

make those neutrons and gamma rays fly off of objects. Right. Okay. Got it. Very, very interesting. The other two instruments, we have a suite of cameras. You better. Yes, exactly. Exactly. And we'll be able to take images both on the surface and in flight. And then we have a suite of atmospheric meteorology sensors and geophysical sensors, including seismic sensors. Another technical factor which I find fascinating about this spacecraft, because it is a spacecraft even though it's mostly a flying machine, is that you won't be able to relay through anything. There won't be anything else in the Saturnian system to help get your signal back to Earth.

Dragonfly is going to have to communicate directly. Right. We do direct Earth communication from the surface. We have a high gain antenna. We're able to do communication directly from the surface of Titan. Fairly efficiently? What kinds of organic molecules do you hope to find? You know, there is a lot of speculation, not just that we will find very complex organics on Titan, but that, as you said, I mean, you're going to be looking for prebiotic stuff, which

this would certainly fall under that classification. A lot of people still speculate on, well, if you did have to figure out how life could have evolved on a body like Titan, here's a possible model. Is Dragonfly going to help us with that? So we know that there's very complex organic chemistry occurring on Titan. We have measurements from the Cassini spacecraft, which actually sampled the top part of Titan's atmosphere and measured very complex molecules, even in the very upper reaches of the atmosphere. And of course, all of those molecules fall down through the atmosphere. And there's this rich haze, which makes it difficult to see the surface, but provides this incredible chemical lag deposit on the surface of Titan. It all just falls out onto the surface of Titan. There are places on Titan,

I mentioned that there's a methane cycle, there's liquid methane on the surface. And so that's, of course, one way that you can have a solvent to interact with these complex organic molecules. One might call it a methane-based primordial soup. Exactly, yes. So there's the possibility for chemical progress in a methane-based system. The surface or the crust of Titan is water ice. Titan is an ocean world like many of the satellites in the outer solar system. There's a deep liquid water ocean and it may be possible for there to be material exchanged between the surface and the ocean. So for organics to get down to the ocean or for water to come to the surface in the form of cryovolcanism.

There are some hints of that in the Cassini data. Of course, Titan has also been subject to impacts. And with a water-ice crust, such impact events would melt the crust. And now you've got a liquid water reservoir that can persist for long periods of time. There's also this opportunity or these opportunities on the surface for the organics to have interacted with liquid water. We know from laboratory experiments that if you combine the types of organic materials we have on Titan with liquid water, you can get amino acids, etc. And so you can get into these prebiotic chemical molecules. This is only making me more excited about what

you may be able to find. How are you going to pick where this machine will fly to? I mean, what will be your targets? The initial landing will be in the interdunes. Titan's low latitudes, the equatorial region, have these vast sand seas, seas of organic sand dunes. We know this from Cassini exploration. So we've characterized these regions well. We know the dunes are made of organic sand particles. We don't know how they form. That's an ongoing question, but we do expect that the dunes will have gathered material from a wide range across Titan. Similar to some of the sites that have been explored on Mars, where material is, you know, we can get a grab bag of materials. And so similarly, the dunes may

offer that widely sourced organic material from across Titan. And so similarly, the dunes may offer that widely sourced organic material from across Titan. But the other reason the dunes are a good place to explore initially is that in between the dunes, there are these very flat, broad inter-dune areas, which not only make for very nice landing sites, but also allow access to material with a water ice component. And so in very close proximity, you have both this rich organic material and material with a water ice component. And so that allows us to get to two different types of materials in a short period of time because they'll be both accessible at the initial landing site. From there, one of the things that's particularly exciting about Dragonfly is that we can scout future landing sites in advance.

We actually will take off, go out, and scout a new area, come back. It's a reconnaissance flight. So we can do a reconnaissance flight. Wow. Exactly. And so then we'd come back to the same landing site, transmit the data, decide where we want to go next, what we want to explore next. I'll expect there'll be lots of energetic science team discussions about that. But what we would do in the long run is have a leapfrog exploration strategy, where once we know where our next landing site's

going to be, we would fly toward that landing site, but then overshoot, go past it, scout a new area, and then come back to the previously scouted landing site. And that way, we have this very efficient strategy to be able to make progress across the surface and also scout each landing site in advance. Is there reason to land close to or on the beaches of Titan, the shorelines of some of those lakes and seas? I mean, you know, of course, I'm thinking of my t-shirt, Surf Titan. There have to be some risk in that as well the the seas and lakes are are certainly very interesting places to explore there are a couple of reasons why we're focusing on the uh the solid material on the surface um rather than exploring the lakes and seas directly

um as as previous proposals of the the time mission that was proposed to explore Ligia Mare, for example. The boat? The boat, yes. Cassini actually did a very good job of measuring the lakes and the seas. The Cassini radar was actually able to penetrate to the bottom of the seas and measure their depths. And that also puts constraints on the material, the liquid

material in the lakes and seas. So we have a pretty good understanding of the liquid composition. And what we don't understand after the tantalizing hints that Cassini and the Huygens probe, which landed on the surface of Titan, gave us, what we don't understand at this point is the chemistry of the solid materials. We have a very basic, we know that they're different materials and we know some have a water ice component, et cetera, but it's at the very high level. And so it's the solid materials that we really, it's a big gap in our understanding of Titan is the nature of the composition of solid materials. The other complication with the lakes and seas is that the timeline for this New Frontiers call, with that timeline, launch would be in 2025,

and we would arrive at Titan in 2034. So that's conveniently, actually, almost a year, almost exactly a year after the Huygens probe descended down through the atmosphere. almost exactly a year after the Huygens probe descended down through the atmosphere. So conveniently, it gives us atmospheric truth. We know what the atmosphere was like at that season on Titan. So that's very good for planning our landing, for understanding what the conditions will be like. But at that time in Titan's year, it will be northern winter.

The lakes and seas, which are primarily at the high northern latitudes, will be in winter darkness. And if the sun isn't up, the earth isn't up. And the direct-to-earth communication strategy requires us to be able to see earth with the lander. Of course, because at that distance, earth and the sun are not too far apart in the sky. Basically the same part of the sky. Very interesting. Right. So initially, we looked at that and said, well, we won't be able to go to the lakes and seas because of the season. But then we also have this scientific imperative to really understand the chemistry of the solid surface on Titan.

For the future, would it be interesting to explore those shorelines, which I assume we may find, and who knows, maybe Dragonfly will at least image some of these. Perhaps there's the equivalent of tide pools. Right, yes, it would be a very interesting place to explore. Dragonfly with the MMRTG, that means that there isn't necessarily a constraint. The MMRTG power degrades slowly. The power output degrades slowly. But we use it to charge a battery. So one can certainly start to dream of longer extended missions where one can go further and further afield.

And, of course, it's exciting to think about having a way of dipping one's toes in the shorelines. Yeah, I'll say. This spacecraft has got to be pretty tough. It's got to withstand the pressure, the cold. And then the other thing that occurred to me was, it's going to have to live through probably some rainstorms, right? Well, we know from Cassini what the seasonal weather patterns are like on Titan because Cassini was able to survive, to explore the Saturnian system for such a long time, for 13 years. It was almost half a Titan year. When Cassini got there, when Huygens landed, it was late southern summer, the equivalent of January on Titan. And the Cassini mission lasted until late June in Titan's year. So we really got to see how the weather changes.

And at the time when Cassini arrived, all of the clouds, the one south polar rain event we observed, that was all at the south pole. There was one other rain event that Cassini observed, and that was at lower latitude. It was actually well after the northern vernal equinox on Titan, and that would be several years after Dragonfly arrives. So we don't expect there to be rain events at the latitude that we're exploring during the mission lifetime. If there were rain, it wouldn't be a problem. Rain on Titan, it's the same temperature as the land or everything would be equilibrated on the outside, of course. The raindrops actually fall very slowly on Titan.

They fall at about the speed of snowflakes on Earth because the gravity is so low. So it would actually be pretty interesting to observe, but we don't expect that to be something that happens in the season that we're active in the nominal mission on Titan. Such an amazing world. We know from Cassini, the radar images, rich visually this this surface is I am very excited about the possibility of getting back these camera shots of canyons and dunes and uh yeah I you you'd clearly agree yeah absolutely um it's a it's a very earth-like place it's a very familiar place and that's what we've that's what we've seen from Cassini. And from the one scene that Huygens was able to observe on the surface, and being able to get to a variety of different geologic settings is, of course, extremely compelling. and being able to understand how the different interactions of geologic processes, atmospheric processes on Titan, how they all work. And of course, to understand the chemistry, we really need the context of the environment.

And so that's one of the reasons that we've chosen the payload we have, because we need not only the specific chemistry at the landing sites, but to understand the landing sites. So we need the atmospheric context and the geologic context, what has brought the materials to the places that we explore. And then, of course, the geophysical context, the nature of the surface, ground truth for Cassini measurements, and even listening for Titan quakes with a seismometer, the same way that InSight is about to be doing on Mars, which is very exciting. All right, so I certainly love the idea that you're going to get so much science out of these images, complementary science, but it's really just those exciting pictures that I

want to see of this world. I reluctantly turn away from Dragonfly. I'll leave you one more question. When will we know if you are allowed to move on to the next phase? So we just turned in the concept study reports. That's the big product from the phase A study. There will be a site visit in the spring of 2019. So the reviewers have the proposal at this point. They will come ask us questions at the site visit to discuss details with them at that point. After that, at some point in the early summer, hopefully, NASA will be making a decision. Best of luck. Thank you.

All right, now on to a mission that is a sure thing, at least in terms of getting it off the ground. I know I shouldn't say that, right? You're allowed to knock on wood. The Europa Clipper, which you are deeply involved with. And we talk with people about this mission a lot, Bob Pappalardo and others. And you're in charge of the imaging system? Yes, the Europa imaging system, or ICE, as we call it, which consists of a narrow-angle camera and a wide-angle camera. So two complementary cameras that will observe the surface of Europa at a wide range of scales to be able to constrain a variety of different aspects, you know, from geophysics to surface geology to searching for plumes. So I think back, as you mentioned plumes, to your mention of

the possibility of cryovolcanoes on Titan. We already know they exist on Europa. That's the point, right? Well, there's certainly some very tantalizing evidence that there may be active plumes or be at times active plume eruptions on Europa. I guess it's more of a sure thing at Enceladus. At Enceladus, yes. There's ongoing cryovolcanic plume eruptions at Enceladus. There, like I said, a number of lines of evidence for that at Europa, but we don't quite yet have the same direct observations of the plumes, of potential plumes at Europa that we've had at Enceladus. But we hope to be able to do that, and the Europa Clipper mission has a large suite of instruments, all of which are designed to be able to study various aspects of the plumes if they're there, and of Europa, all of which are designed to be able to study various aspects of the plumes,

if they're there, and of Europa, regardless of whether or not there are plumes. Another beautiful world. Your cameras will be sending us beautiful images of this place as well. It's really exciting to be looking forward to getting back to Europa, being able to observe the, you know, Europa as a system in that it has, you know, potential plumes, the surface geology, how the ice shell works, potential exchange processes, you know, through the ice shell to the subsurface ocean. And with the cameras, of course, we get to look at that at a variety of scales, from the very high-resolution meter scale to global mapping of the world, of Europa as a world. Has Europa Clipper, the planning of this mission, benefited from previous missions there? I'm thinking particularly of the one that's

still underway, Juno, which is doing a pretty good job of surviving in that nasty radiation environment. Yes, any of the spacecraft that have been in or gone through the Jovian radiation environment provide us information about the radiation, and that's very useful for designing the spacecraft, for understanding how much shielding we need for the instruments or other components of the spacecraft, absolutely. I haven't talked to anybody for a while now about the current status of Europa Clipper, but I take it things are moving along. Yes, things have been moving along at a rapid pace. Instruments are actually all coming up on the critical design reviews at this point, starting this winter.

Getting through those and then really getting into building the flight equipment. Very exciting times around our solar system. Yes, there's a lot going on. You've been at this for a while. There's a lot going on. You've been at this for a while. You're getting these opportunities now to explore in ways that we've never, no one even dreamed of until fairly recent years. And now some of them at least are becoming reality. I just think of how your field of planetary science has changed compared to its, you know, its genesis years when even the term was still being defined

by people like Carl Sagan. It must be a pretty good feeling. It's amazing to look back and see how far we've come and how much we know now and how many questions, right? Every new step brings new questions with it. Going back to the Cassini mission and Titan, when Cassini arrived, we only knew that there were large areas on the surface that were somewhat brighter and somewhat darker, you know, in the infrared. That was all we had was the remote telescopic observations at, you know, the scale of a thousand kilometers across the surface. And in the span of almost a blink of an eye, Titan went from that to an incredibly familiar place with, you know, where we know the surface geology and we know the geography, and we've gotten to observe the seasonal cycle of weather. And so to think of just how quickly, you know, a place can go from being unknown to being familiar is amazing. And, of course, we've done that for many of the worlds in the outer solar system in just the last couple of decades.

It's been a great adventure. I hope we keep it up. Absolutely. Wish you the greatest of success with these projects and everything else that you're up to, Zibi. Thanks very much. It's been a pleasure to talk to you. It really has. Thanks. Elizabeth Zibi-Turtle is Principal Investigator for the Europa Imaging System and the Dragonfly Mission. She is a planetary scientist in the space exploration sector at the Johns Hopkins University Applied Physics Lab. Time for What's Up on Planetary Radio. The chief scientist of the Planetary Society is here with us. That's Bruce Betts.

Welcome. Welcome. Welcome to you, Matt. How are you feeling? Not as well as I would like, which probably people can hear if they haven't noticed already during the show, but the show must go on. And so we carry on. You're a trooper. Thank you. That's what I wanted to hear. I was trying to come up with some space theme thing, but I'll leave it as showbiz. Tell us what's the show in the sky? You're a space trooper. That's opposed to a star trooper. Sure. Yeah, exactly.

So up in the sky, we've got that total lunar eclipse happening on the night of the 20th to the 21st. And the maximum total eclipse will be at 512 UT on the 21st. That's 2112 Pacific Standard Time for us. The total lunar eclipse will be visible throughout most of North America, South America, the Eastern Pacific, the Western Atlantic, Western Europe, and even into Eastern Europe. It'll just end Eastern Africa because it's visible in Western Africa. And even in the eastern parts of that, they'll still catch the end of the eclipse. It'll be cool. Let's hope for clear weather across the world. It's a worldwide sensation.

Nearly. It's half a worldwide sensation anyway. And then in the pre-dawn, we've got that Jupiter-Venus dance going on. So Venus super, super bright, Jupiter just super bright. They will be very close together on the morning. That's the pre-dawn east on the morning of the 22nd of January, where Jupiter

will pass Venus from night to night, heading farther up and getting above Venus to its upper right. Is that clear, Matt? Can you understand that through your... I got it. I won't add anything. It'd be more foolish than usual for me to add anything else. But yes, I did get it. Thank you. All right. I feel like you're the one who's sick and I'm the one who's incoherent. But I guess that's no different than usual. Don't make me laugh. Please. It was 1969 this week that we had the first docking of two spacecraft that actually both had humans on board, Soyuz 4 and Soyuz 5. And now, on to random space facts! I wish I could have said that. I wish I was capable of saying something like that. I was trying to put the energy in it for you. Maybe it'll transfer.

This one's kind of obvious, but I mention it in case people haven't thought of it. If you're on the surface of the moon, then your day-night cycle is about 29 and a half Earth days long. So you've got day for a little over two weeks, Earth weeks, and night for over two weeks. And so if you're a spacecraft on the surface, like the recently landed Chang'e 4, you experience about two weeks of daylight and two weeks of night, which plays havoc with thermal control because the surface of the moon will change hundreds of degrees, no matter what your temperature system pretty much. Do you think there's anybody left in our audience, more broadly, I'm sure there is, who still thinks of where Chang'e 4 is as the dark side of the moon? Well, it depends on how you answer that. In terms of, as opposed to the far side. No, I hope not. But it is, for example, when we're recording it, the dark side right now, it just changes from the dark

side to the light side. So it's chilling hard in lunar night. So it's the temporary dark side. So you're saying that within a few hours, I'll be living on the dark side of the earth. a few hours, I'll be living on the dark side of the earth. Exactly. It does exist. We move on to the trivia contest. This was the fun one for me because I don't think I ever have asked a question that we didn't know the answer to when I asked it, but now we know the answer. I asked, is 2014 MU69 nicknamed Ultima Thule that New Horizons flew by between when we asked this, when we answered this. Is it a binary, two objects, a contact binary, two lobes, or none of the above? How do we do, Matt? This was really fun. I mean, you remember how thrilled I was when you posed this question two weeks ago. The audience felt the same way. At least the very large group of people who entered this

time had a great time. And we had people who were like just chomping at the bit, waiting for Alan Stern and his team to flash that image up on a screen so that they could enter the contest. Well, I'm glad I made the flyby exciting because otherwise it would have been boring. I'm kidding. That was sarcasm. I know you are. Here's our winner, Josh White. I know he's right because I was there. Josh White in Sweetwater, Tennessee, as far as I know, a first-time winner. He says Ultima Thule 2014 MU69, if you prefer, is a contact binary. That is correct. We see it as the contact binary, otherwise known as a snowman. Yeah, two lobes. Congratulations, Josh.

You have won this one. You are on top of it. A question that could not be answered until about a week and a half ago, less than a week and a half ago. We are going to send Josh a set of those really fun, terrific Kik asteroid stickers, all five, a complete set from Chop Shop Store. ChopShopStore.com is where you can check them out. Co-designed, is that fair to say, by Bruce Betts? Yes. It may be taking a little too much credit. I did none of the art, so don't worry. I just assess the scientific validity in an iterative process. You consulted on their design.

There you go. That's impressive enough. Okay. And a 200-point itelescope.net astronomy account for that worldwide network of telescopes. And I do have others, of course. Paul Bergel in Brooklyn, New York. He says, New Year's Eve was cool and all, but the real countdown was at 1233 a.m. on January 1st. That's if you're in the Eastern time zone. He says,

happy fool year. No, I get it. Steve Wienel in Antelope, California, another guy we've heard from before. He proposes a new name for this asteroid, Ultima Frosti. And you know why. It's because so many people, including Alan Stern, compared it to a snowman. But it has been compared to other things, and they were kind of all rounded up by Jonathan Aguilar in Baltimore, Maryland, very close to where I was.

Its shape has been compared variously to, sure, a snowman, Star Wars BB-8, that little droid, Kenny from South Park, and an odd peanut. He says, to me though, it reminds me most of my 11-month-old daughter Vera back when she was still small enough to be swaddled and quite pink. This is from Bob Klain in Chandler, Arizona. Would you and Bruce consider yourselves to be a contact binary when you're shaking hands? Yes. I also fight about who's the zero and who's the one if we're really binary. But we definitely know who the bigger lobe is.

Dave Fairchild, our poet laureate, will close it out. MU69 we've seen has bodies tied together, and like we saw with Philae, lobes are closer than a brother. We're two for two in visiting these solar-kissing cousins with billions more to find

that we can add to the discussion. All right, we're ready to go on. For next time, what 180-kilometer diameter crater did Chang'e 4 land in? And who is the crater named after? Go to planetary.org slash radio contest. You've got until the 23rd, January 23rd, Wednesday at 8 a.m. Pacific time to respond. And we will have for you, we'll give you another set of those stickers, the kick asteroid stickers from Chop Shop. We will also give you a 200 point itelescope.net account. I found the other day, and I really had

forgotten that I had this, yet another signed copy of Chasing New Horizons, Inside the Epic First Mission to Pluto by Alan Stern and David Grinspoon. It's an excellent book. Some of you will remember that I talked with both of the authors some months ago, well before the flyby of this latest object. And as I said, this one is signed by Alan Stern himself. So get in on it. As I said, this one is signed by Alan Stern himself. So get in on it. And a little preview. I've been hinting.

Now it can be told. Not this week, but in next week's contest, the return of the rubber asteroid. Yay! I know, long overdue. We're done. You've done a masterful job, Matt, working through your sickness. So everyone, go out there, look up at the night sky, think about Matt's health and your own and how to improve them. Thank you and good night. I'm going downstairs now to have some hot tea.

Bruce is the chief scientist at the Planetary Society and he joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, Planetary Radio is produced by the Planetary Society in Pasadena, California and is made possible by its high-flying members Mary Luz Bender is our associate producer Josh Doyle composed our theme which was arranged and performed by Peter Schlosser I'm Matt Kaplan at Astro