Planetary Radio: Space Exploration, Astronomy and Science - A Mission to Earth: OSIRIS-REx

Episode Date: January 2, 2019

Why do so many spacecraft that are headed across our solar system turn their instruments back to Earth during flybys?  OSIRIS-REx was no exception. The answers come from mission scientist Vicky Hamilton.  She has also written about the topic in The Planetary Report. Planetary Society CEO Bill Nye helps us ring in the new year, while Bruce Betts leads the first What’s Up of 2019 with exciting news about the night sky. Learn more at:  http://www.planetary.org/multimedia/planetary-radio/show/2019/0102-2019-vicky-hamilton-osiris-rex.htmlLearn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

A mission to Earth, this week on Planetary Radio. Welcome, and Happy New Year. I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. By the time you hear this, Osiris-Rex may be orbiting no more than 2 kilometers from a messy, mysterious asteroid called Bennu. The spacecraft is already revealing Bennu's secrets, according to Vicki Hamilton. This comes after the probe tried out its instruments when it passed our own, much bigger rock.

Vicki is here to share much more with us. This holiday edition of our show has also allowed me to head for the Applied Physics Lab near Baltimore, where I'm covering the thrilling New Horizons flyby of faraway Ultima Thule. Don't worry, I still found time for our regular What's Up visit with Bruce Betts. And we can now share a special greeting from someone else, Planetary Society CEO Bill Nye. Bill, welcome back to the show and happy new year. I thought that you might want to share greetings for this year that we have just begun, 2019. It is an amazing thing to me that there is such a thing as 2019. Fascinating. When I was a kid, the 21st century was this remote future. But here we are. And on top of that, we have continued to

explore space and learn more about the solar system and our place within it and so on. So, as we speak, the remarkable spacecraft, OSIRIS-REx, is going to be in the proximity of the asteroid Bennu, which was named by Mike Peasey, who was in third grade at the time. Now he's in college, for crying out loud. It just takes a long time to get to these remote destinations in the solar system. But we learn more about our place in space with every mission. And Matt, as we talk about 2019, I think about the next decade, what people are going to call the 2020s. And I'm very, very hopeful that we are able to bring back samples from Mars, rock samples from Mars, and very hopeful that we are able to design missions to really look for life there on Mars. and in the 2020s, we're going to have a probe going by Jupiter's moon Europa,

the Europa Clipper mission, and it's going to be fantastic. It's going to send back pictures that artists have imagined for decades, and we'll see what it really looks like up close. This is a very, very exciting time. And as we speak, I believe the government is shut down, but the NASA administrator has the influence to keep NASA television going as we go by this crazy distant object, Ultima Thule, which is, we presume, a body similar to Pluto. Well, by the time people hear this, we may have a much better idea of how much it resembles Pluto.

It is very good of the administrator to make sure that that coverage will continue. And as we speak, I'm just about to head for APL, the Applied Physics Lab outside of Baltimore, thanks to the Planetary Society and thanks to our members who've enabled us to- Who bought you a plane ticket. They bought you a plane ticket. Thank you, members.

It's true. But Matt, while you're there, you're going to do like four shows or something, right? It's a value. I'm going to get a whole bunch of stuff. What would you call this? It's a four for one. I'm going to be talking to a whole bunch of other people, including Zippy Turtle, who is the principal investigator for what we hope will be the Dragonfly mission to Titan. So you're right, exciting times, and the Planetary Society is standing behind all this.

It really is, everybody. And so if you're out there listening and you're a Planetary Society member, thank you. If you're not a member yet, think about joining us because we work with the U.S. Congress especially to advance the space science missions that we feel are the best value to humankind. And there's talk now about renewing or authorizing the NASA budget for three years rather than one year. And that would be really good because it keeps things stable in the space industry. Well, these are details. But, Matt, Happy New Year, and let's fly by Ultima Thule. Let's have a look up close at Bennu and learn more about our place in space.

Thank you, Bill. Happy New Year to you. This is a great way to start the new year, with a conversation with the CEO of the Planetary Society. I look forward to talking to you across the entire year. Onward! Like all missions of exploration around our solar system, there's a big and talented team behind OSIRIS-REx. It takes engineers, scientists, administrators, navigators, technicians,

even accountants to get us successfully to other worlds or to explore them from afar. Vicki Hamilton is an important contributor to this mission. She is the Deputy Instrument Scientist for the OSIRIS-REx Thermal Emission Spectrometer, or OTIS, and she leads the OSIRIS-REx Spectral Analysis Working Group. As you'll hear, the spectrometers on board the spacecraft are critical to its successful remote investigation of Bennu. OSIRIS-REx reached its destination just weeks ago after traveling for more than two years. Its mission won't end till it returns a precious sample in 2023. But it has already made one brief but essential return to Earth, and Vicki has written about this flyby.

Welcome to Planetary Radio. It's a great pleasure to have you on to talk about Osiris-Rex, something we've done a couple of times in the past with Dante Loretta, and we will again fairly early in the new year, 2019. But of course, we want to talk to you partly because you are the author of this great article in the brand new December solstice edition of the Planetary Report. It's called Flying by Home, Testing OSIRIS-REx's Tools on the Way to Asteroid Encounter. It's a great article, and we will link to it from this week's show page that the people can get to from planetary.org slash radio. page that the people can get to from planetary.org slash radio. So congratulations on that. But most of all, congratulations on the tremendous success so far of this mission. Thank you. I'm very happy to be here and excited to talk about what we're doing. So this is one fascinating, dirty little

rock that you folks have reached. Is Bennu turning out to be everything you had hoped for? So far, absolutely. We were not sure how much we would see in terms of the compositional information in particular, which as you mentioned, is my specialty. But very early on in our first data sets, we've made some really great identifications and discoveries already, and we're definitely at the object we wanted. I saw that December 10th press release that said that, thanks in part to the instrument that you most closely work with, that you found water on Bennu. Yeah, we've seen certainly evidence of water inside minerals, not liquid water on the surface. But yeah, we see evidence from both of our spectrometers that we have minerals on the surface that have water in them.

And that is exactly what we came to find. Was that any kind of a surprise or was this expected? I think it was expected. That's part of the reason we chose Bennu was because we had telescopic observations from the Earth that suggested that this asteroid should be very similar to a group of meteorites called carbonaceous chondrites. And these are meteorites that very commonly contain water. So that was part of the reason we chose Bennu. And so it was expected. It's always nice to have your expectations confirmed, though. You bet.

Remind us of why it's so important and hopefully going to be so fascinating to bring back a little piece of this so-called carbonaceous chondrite asteroid. One of the primary ways we study asteroids, other than looking at them through telescopes and measuring their spectral properties is by looking at actual samples of asteroids that we have on Earth. And those come to us in the form of meteorites. The hitch, though, with meteorites is that before we can get our hands on them to study them, they have to come through our atmosphere. They land on the earth. They interact immediately with our hydrosphere and our atmosphere and our biosphere. Even if you go out and pick up a meteorite within a day of its falling, it is already starting to change in its

properties, its chemistry, because of the fact that it's interacting with our environment. What we're trying to accomplish with OSIRIS-REx is to get away from that. We want to go to the asteroid, pick up a pristine sample, and bring it home in a controlled environment so that we don't have that interaction with all the things that we know about or are related to Earth, we want to be able to study this object without any of those interferences. So once again, we learn the importance of sample return pretty much everywhere around the solar system. No less true in the case of Bennu, I suppose. But it's a hard thing to do, isn't it? It is. It is. The very first thing that's really hard to do is even get to an object like this. I mean, Bennu is only about 500 meters in diameter. I mean, it's a very, very small object. You can walk that far in 10 minutes. it, it has almost no gravity. So we have to operate a spacecraft in this micro gravitational environment and do all kinds of different observations, let alone actually contact the object in order to pick up the sample and do all of that safely, and then be able to bring it back

and launch that sample back from the spacecraft to the earth. So there's a whole lot of steps, many of which have never really been done before. Now, as people hear this, this may have already happened, but I read that OSIRIS-REx may be accomplishing orbital insertion on December 31st, New Year's Eve, when it will go down to no more than two kilometers from the surface. But how do you orbit something that is so small and has so little gravity of its own? Well, that's actually a really great question for the spacecraft team. The engineers, yeah. Yeah, exactly. The people who have to fly it.

Ultimately, I think orbit is a word that kind of comes with quotations around it because it really isn't an orbit in the classical sense of how you might orbit the Earth or orbit Mars or orbit another planet. There's a lot of sort of station keeping and little thruster firings and things that help keep the spacecraft stable at all times. But yeah, we are going to go into our first quote unquote orbit on the 31st. Pretty exciting. Hopefully that will have gone perfectly by the time everybody is hearing this. Let's ignore this climactic event of sample return for a few moments because you have these great instruments that we've talked with Dante Loretta

before on this program. And we don't need to go through all of them here, although they are all very well described in your article in the Planetary Report. Just stick into your own field. Is there anything special about the infrared instruments on OSIRIS-REx? I think one of the most special things isn't the instruments themselves per se, but the fact that we have them both. Most spaceflight missions don't carry two spectrometers to cover both the visible infrared part of the spectrum as well as the thermal infrared part. And that is one of the uniquenesses of this mission is that we have spectral coverage from the visible all the way

out into the infrared. You know, this is the first time a thermal infrared spectrometer has ever been sent to an asteroid. Previous missions have always sent visible and near-infrared spectrometers. So I think we're doing a lot of new things here for the first time. And this discovery of these water-bearing minerals on Bennu, I guess that's a good indication of the value of these instruments. Absolutely. We first identified an important spectral feature from the visible and infrared spectrometer OVIIRS. And then it was just a few days later when we were looking at the thermal emission spectrometer data from OTIS, is the name of the instrument, and were able to see completely different set of spectral features that drew us to the same conclusion.

So it was really nice to be able to say, okay, we saw one thing with one instrument. Do we see something similar with the other instrument? And since they're measuring two different things but coming to the same conclusion, that's really, really encouraging for us. Tell us about OTES, which is O-T-E-S, by the way, since that's the instrument that you are most frequently dealing with. It's a really neat little instrument. It's got a lot of heritage from previous missions, primarily Mars missions. So this is the fourth version of this instrument to fly in space. I'm really excited to be associated with it, again, because

it is the first time we've taken an instrument like this to an asteroid. And it, I think, is going to give us a whole new view of what we're looking at. Let's turn to what is the main topic of this article you did in the Planetary Report. The most studied planet in our solar system has got to be our own Earth. So why do so many spacecraft, including OSIRIS-REx, that are headed to other worlds, why do they point their instruments homeward when they have the opportunity, when they're flying by? Well, a lot of times, some of these missions, between their launch and when they actually arrive at their destination,

it can be many, many months, if not many, many years. And in that entire time, you generally don't have anything to look at other than deep space. And so you can look at deep space with a camera and you can see stars and know that the camera is working correctly. But with instruments like our spectrometers, you look at deep space and there's nothing to see there. And our spectrometers are not imagers. They just collect light. They don't make images. And so when there's nothing to see out in space, all you can know is that the instrument is turning on and collecting data, but you don't know what the data quality is. So when we have the opportunity to fly past the Earth during an event like a gravity assist, we have an opportunity where we're close enough to a target

that is going to give us a signal, and we even know what that signal should look like, that we can actually collect those data, verify that the instrument calibrations are working as we expect them to, we can make modifications if we need to. And like I said, since we know the Earth so well, we know exactly what we should be seeing. You mentioned up front in the article that you ran into that classic, very cordial tension between a mission's scientists and the engineers who of course are charged with getting it safely to its destination so that you can do lots of good science there. Talk about how that

became part of the game as you were looking at this flyby of Earth. Yeah. Not every mission is fortunate to have a flyby like this. And so the science team was really excited about the opportunity to collect these data. And as you say, and as I mentioned in the article, you get very, very excited about any opportunity to collect data as a scientist. That's what we're all about. But the folks flying the spacecraft have a very reasonable concern that any kinds of turning the spacecraft to look back at the Earth or having to turn on the instruments, all of those events have the potential to send a bad command or, you know, make some mistake that could endanger the spacecraft. And so their job is to say, well, do you really need to do this?

How important is it? How do we fit this in at a time where we don't risk the spacecraft? And so, you know, it starts out as we go to the project and say, you know, hey, we'd like to make these observations, the spacecraft team gets involved, they want to know exactly what we want to do. How do we want to do it? When do we want to do it? And then basically, it's just an ongoing discussion for many weeks or months to say, when can we fit this in at a time where it's least likely to pose a risk to the spacecraft? Can we do it without overworking the spacecraft team? Because we don't want them to be working so hard that somebody accidentally makes a mistake. It's

happened. Like you said, we're trying to get data, they're trying to keep things safe, but ultimately we all want what's best for the project. And so we have this discussion and we came up with a plan that we executed and got great data. Give us a little overview of that plan. You go into much greater detail in the article and it obviously went pretty well. I'll bet the engineers were also pretty thrilled to see that everything was working properly. Oh, yeah. I mean, I have to give all kudos to the spacecraft engineering team. I mean, they are very excited to see these data when they come back as well.

It's a lot of their relative to the Earth's orbit. shot right past the Earth at our closest approach, as soon as everybody knew that the spacecraft was okay and working the way it was expected to, we turned the spacecraft back to look at the Earth. And so we did that the day of the gravity assist, so within a few hours of the event. And then we did it again on day three after the assist and on day six and 10, the idea was that we wanted to have backup observations so that if something went wrong on that first day and the spacecraft team had to deal with some anomaly that we couldn't get the data on day one, we would have opportunities on day plus three, plus six, and plus 10. And in the end, everything worked flawlessly and we got all of those observations. Yeah. And there are some great results of that.

In fact, there's a great full page sidebar in the TPR article that graphs the actual results from Otis as it was observing Earth during one of these observation periods. Can you describe what it shows us? Sure. So there are two guidelines on that graphic. There's a dark blue curve and a sort of turquoise curve. And they're nice, smooth curves. And what those represent are the amount of energy coming off of an object that's the same temperature as either the ocean surface or the

upper atmosphere in those two cases, what that energy would look like if there was nothing around to absorb that energy. So if you didn't have an atmosphere, if you didn't have water, if you didn't have anything to measure at all, you would simply be measuring the temperature flux coming off of the object. But once you actually have an atmosphere, and that atmosphere has molecules, those molecules interact with light. And so you don't get that nice smooth curve, you get these absorption features or these dips in the curve that tell you what is actually there interacting with the light. In this particular graphic, at the left-hand end, there's an absorption that we know is due to methane. There's absorptions due to ozone in our atmosphere, carbon dioxide in our atmosphere,

and even the water vapor that is around all the time. So almost every single bump and wiggle in the yellow spectra in that plot is meaningful. It's telling us something about what we're seeing. We know very, very well from years of looking at our own planet, what these features are and what they're due to. And so this is what this graphic is showing us. Is this more or less the equivalent of what we would see in a visual-like representation of spectra where the dark lines are? Because there's light at that wavelength is being absorbed. It's similar. It's not identical. So at the wavelengths that our eyes can see, what we're looking at is reflected light, the light that comes from the sun and reflects off of surfaces and to our eyeballs, which are our sensors, our instrument.

These longer wavelengths, what we're measuring is the energy that's just naturally emitted. So if you are out hiking in the summertime and you walk up to a rock and you put your hand over that rock, you'll feel heat coming off of it. That's what we're measuring. And so it's slightly different. And what's happening in this case is that some of the heat is not getting back out of the rock again because it's been absorbed by the rock. Okay. Okay. Is this the same kind of infrared observation that is being done satellite is an Earth-observing satellite, and it has an instrument that is not the same but similar to OTIS on board, and it measures the Earth. And so in that particular case, we are measuring around looking at water vapor,

looking at both at the Earth's surface as well. And so in that regard, that is somewhat similar. It just occurred to me that I should breathe a little sigh of relief to see that dip that represents the ozone in our atmosphere. Good to see it's still doing its job. Yeah, exactly. This wasn't the only thing that happened, of course, during these Earth Gravity Assist observation periods. You got some beautiful images, too. I'm sure you know that we just saw the 50th anniversary of the snapping of that famous

Earthrise image that was captured by the Apollo 8 crew. And now OSIRIS-REx has captured its own beautiful images of Earth. These really are pretty stunning. Yeah, they really are gorgeous. What's actually even more impressive about this is that the Earth, it reflects about, I don't know, on the order of maybe 20 to 30% of the sunlight that falls on it. Bennu only reflects about 4% of the sunlight that falls on it. And so when we built these cameras for the mission, they were designed to look at something very, very, very dark.

I like to use the analogy that Bennu has the darkness of a charcoal briquette. It's black. And so if you've ever taken a photograph with a camera where you've had to adjust your shutter speed or your aperture to cut down the amount of light so that you don't overexpose. That's what we really had to do to get these pictures because the Earth is so, so much brighter than Bennu. The cameras really weren't designed to image something as bright as the Earth. And yet we did, you know, the team did a really remarkable job of figuring out how to get those images so that they weren't saturated. There are a couple little spots up near the poles, up near the top of the images,

where we have these little things that we call icicles. And those are basically places where the Earth's surface and the clouds and all of that were too bright for the camera, but the rest of it is just, it's stunning. Speaking of gorgeous images, I called it a dirty little rock. Bennu is really pretty fascinating, isn't it? I mean, it's just covered with stuff. Yeah. It's really surprised us in some ways. Everybody expected it to be a little bit rocky. I think some people expected it to be a little bit rocky. I think some people expected

it to be a little less rocky than it is. We have this huge boulder sitting on the surface that in the article, you can actually see it sort of sticking out on the lower left side. And that thing is 50 meters in size. It's enormous. We don't yet understand where that came from. We see a lot more variation in brightness on the surface than we were expecting. I mentioned a minute or two ago that the average reflection from Bennu is only about 4% of the light that falls on it. And yet when you get pictures as we have now, at scales of 35 centimeters or so, you can actually see that there are some little rocks on the surface that are considerably brighter than that. And so we're really looking forward to figuring out what that means. Well, the best is obviously yet to come.

What are you most looking forward to? I'm really looking forward to two things. I'm looking forward to getting much higher resolution spectral data on the surface. Everything that we've collected so far, our spatial resolution, the data that we're getting is from very large areas on the surface. So Bennu's about roughly 500 meters across in diameter. We're looking at areas that are sort of 50 to 100, 200 meters across. And so I'm really looking forward to the time when we get down to looking at things at the 40 meter scale or the 20 meter scale or the eight meter scale when we're doing our reconnaissance for the sample site selection.

So I think that's going to be really fascinating. And then of course, the other part I'm really excited about is actually the return sample, because part of what I do is I run a lab where we collect spectral data from geologic samples and from meteorites. And so I'm really looking forward to getting some of that sample into the lab and comparing it to meteorite spectra. Wow. That really is going to be thrilling. meteorite spectra. Wow. That really is going to be thrilling. Thank you, Vicki. Please tell Dante and the rest of the team, give them our best wishes for continued success of this mission, which has already gone so incredibly well. So it's not incredible. It's just wonderfully well. And I look forward to talking to you again. Boy, it's a ways off, but I sure would love to talk to you again when you have that little bit of Bennu there in your lab to examine it right up in front of you.

That would be great. Thank you very much for doing this. Oh, well, thank you very much for asking. I love being able to talk about what we're doing. Vicki Hamilton is a staff scientist and the acting section manager for planetary physics in the Southwest Research Institute's Department of Space Science. That's where she studies what other worlds are made of. She has that lab that she mentioned, where that is also devoted to thermal infrared spectroscopy of planetary materials. And she leads the OSIRIS-REx

Spectral Analysis Working Group and is Deputy Instrument Scientist for the OTIS Spectrometer. Time for What's Up on Planetary Radio. Bruce Betts is the Chief Scientist for the Planetary Society. He has been with me on this segment throughout many years now and will be with me throughout 2019. Welcome and Happy New Year. Happy New Year, Matt.

We're ready to jump in. We've got a lot of great stuff to talk about today. So go ahead, hit it. Tell us what's up there. January 6th, partial solar eclipse visible in parts of Eastern Asia and Northern Pacific Ocean. January 21st, a total lunar eclipse visible throughout most of North America, South America, Eastern Pacific, Western Atlantic, Western Europe, Western Africa. It's going to be a party. January 21st, total lunar eclipse. Pre-dawn, got super bright Venus in the east and below it is Jupiter. They will actually be switching places on January 22nd or thereabout. And Mars still in the early evening in the southwest looking reddish. Busy.

And how? We move on to this week in space history. It was 15, that's the number, 15 years ago, Matt, that we celebrated not only the Spirit landing on Mars, but the stardust fly-by-fly-through of the VIL-2 comet, COMA. Wow, 15 years. We're still trying to talk to Opportunity as we speak, so let's hope that that is a nice New Year's present before too long. Random Space Fact.

But the last time that 2014 MU69 was in the same place in its orbit as when New Horizons flyby is happening now, it was 1722. More than 120 years before even Neptune was discovered, much less Pluto and the Kuiper Belt objects. Yes, the period of 2014 MU69 is 296.44 Earth years. So you were just a wee little child. I think I was a toddler learning to walk. It was either that or I was learning to hoist the mainsail. All right, we move on to the trivia contest. I hear you've got a lot of responses, so let's get right to it.

How many orbits did Apollo 8 complete of the moon? How'd we do, Matt? Great. Very, very well. I am going to let our poet laureate, Dave Fairchild in Shawnee, Kansas, answer this for us. Borman and Lovell and Anders were asked to fly out to Luna and back. It took them three days from the Earth to the moon in a sky that was inky and black. And when they were ready for lunar insertion aboard the best bird they could find, they turned on the service propulsion ignition while sailing around the backside. Insertion was perfect and all of the folks back at mission control breathed again. The crew circled Luna and headed for Earth when the orbiting count got to 10. Very nice, very nice. Well done. And he's right, right? Yes, that is correct. Dave, we don't have a prize for you, except for, of course, your continuing recognition as the Poet Laureate,

but we do have one for first-time winner, Dan Glenn in Palm Springs, California, probably a neighbor of my mother's out there. Dan indeed said it was 10. He added, hey dudes, happy and safe holidays. We got so many nice holiday wishes from listeners. And thank you to all of you. I can't answer all of you on air or otherwise, but know that I've read them all and they are much appreciated. By the way, for Dan, we have Robert Kirson's great book about Apollo 8, Rocket Men, and a Planetary Radio t-shirt from the Planetary Society Chop Shop Store at chopshopstore.com. And of course, a 200-point itelescope.net astronomy account, which he can use to observe the moon. It's always a nice thing to look at with the telescope. I got a few more if you're ready.

Adam Ladak in Scarborough, Ontario. He said 10 is also the number of minutes. Apparently, it took James Lovell to calculate the correct numbers to realign the module's inertial measurement unit. Talk about being reactive. And I think that was after that issue that they had coming back to Earth that Robert Kirson wrote of in his book and told us about two weeks ago when we talked to him on this show. From Bruce Goodman in Ada, Michigan, he says,

Wish I could say they inspired the Beatles to write Revolution, but in reviewing the lyrics, I see that is not true. Number 10, number 10. Andrew Zimmerman in Tokyo. A couple of heart warmers here. He says, what a fantastic episode. I am a child of Apollo. I was just shy of four

years old, but vividly remember sitting in my father's lap watching Eagle land on the moon in July of 1969. Apollo 8 laid the foundation for this remarkable achievement. In that vein, Kay Gilbert in Manhattan Beach, California. She says, I'm 30 years younger than Jim Lovell, but my first grade teacher in Milwaukee, Sister Charlene, taught him too. She always bragged about astronaut Jim and his missions. Finally, from Torsten Zimmer, our friend in Germany who can almost always be counted on for laugh, he says, it just occurred to me that Earthrise, if it had been shot today, would probably be a selfie. What? You don't like that? I thought that was hilarious. I'm still trying to figure it out.

Your arm's not long enough. That's the problem. Okay. We can move on. All right, Matt. I think this is the first time I've ever done this in the trivia question in all these more than 16 years. I'm going to ask a question that no one knows the answer to at the time I'm writing this. So it could lead to some confusion depending on how things come back from New Horizons. But answer me this, people. Is 2014 MU69 or Ultima Thule a binary, in other words, two separate objects, a contact binary, in other words,

two objects that seem to be stuck together as one object with two lobes, or none of the above? Depending on what New Horizons finds, this could be easy to answer or hard to answer. But in any case, go to planetary.org slash radio contest and tell us what you found that New Horizons found. I love this. You're right. This has never happened before. Now, of course, we're, because I have to head to APL, we're recording this days ahead of the encounter with 2014 MU69, Ultima Thule.

This will be really fun. You have until the 9th, January 9th at 8 a.m. Pacific time. That's a Wednesday, of course, to get the answer for this one. And I think we will once again give away a set of those great stickers, the Kik Asteroid stickers from Chop Shop that Bruce Betts had a hand in helping to come up with, helping to design. They're part of the Kik Asteroid campaign that the Planetary Society put on, and you can see them at chopshopstore.com, along with a 200-point itelescope.net account. That's it. We're done. All right, everybody, go out there, look up the night sky, and think about 2019 and where you want to go in life, in space, or in jello. Thank you, and good night. I like that blue jello. I'm going to dive into that inner space. He's Bruce Betts, the chief scientist of the Planetary Society,

and he joins us every week here for What's Up. Like our show? Please share it with others by leaving us a rating or review somewhere. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its new and veteran members. Mary Liz Bender is our associate producer. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan at Astro.