Planetary Radio: Space Exploration, Astronomy and Science - OSIRIS REx: Ready for a Voyage to Bennu

Episode Date: June 21, 2016

OSIRIS-REx will launch toward Near Earth Asteroid Bennu soon. In an early celebration of Asteroid Day, mission leader Dante Lauretta tells us how learning about asteroids may teach us about our own origins, and help us avoid a cataclysmic impact.Learn more about your ad choices. Visit megaphone.fm/adchoicesSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

Celebrating Asteroid Day with Dante Loretta, this week on Planetary Radio. Welcome to the travel show that takes you to the final frontier. I'm Matt Kaplan of the Planetary Society. Very soon, a spacecraft named OSIRIS-REx will depart on its mission to an asteroid named Bennu. IRIS-REx will depart on its mission to an asteroid named Bennu. The leader of that mission returns to our show with an update and an eloquent explanation of why we need to learn more about these small companions in our solar system. There's still a lot to look at in the current night sky.

Bruce Betts will tell us what and where. Next week, my guest will be Scott Bolton, principal investigator for Juno, which arrives at Jupiter on July 4th. Senior editor Emily Lakdawalla has prepared a minute-by-minute timeline for that first encounter. Emily, I remember so well, I believe it was much more than seven minutes of terror, when Cassini was doing what Juno will be doing very soon. Tell us what's on this timeline. Juno will soon be entering orbit at Jupiter, and it gets only one shot at doing this correctly.

So it is a somewhat terrifying moment for the mission. Juno will be firing its rocket engine for a total of 35 minutes in order to change its orbit from one that's orbiting the Sun to one that's orbiting Jupiter. It's got to be nerve-wracking for the people who are going to be at JPL, and I know that you'll be there among them. It really is, made all the more so by the fact that nobody that you'll see in mission control on the day of orbit insertion will actually be able to do anything about it if something goes wrong, you know, because they're all observing things that happened 48 minutes in the past, according to the spacecraft. We'll all be watching

for the radio signals from the spacecraft. They'll be looking for a distinct shift in the frequency of those signals, kind of like a, it's a Doppler shift that'll let us know that the velocity of the spacecraft is changing as it's supposed to as the engines fire. As long as the engines fire for at least 20 minutes, Juno will be in Jupiter orbit and anything that happens after that can be cleaned up later. So that's really the critical number. After it starts, it's got to fire for at least 20 minutes. Five times the terror for your space exploration pleasure. Coming up from Juno on the 4th of July,

you'll find it all in Emily's blog posted to planetary.org on June 16th, including this terrific timeline of what to expect as Juno goes into orbit at Jupiter. On that very same day, you posted this little image from ExoMars. Yes, it's not the most impressive image of Mars, but it's really important. It's the first deep space image of Mars from the science camera on board ExoMars Trace Gas Orbiter. And it's just a little taste of what's to come from the mission when they do enter orbit in September. So Mars ho, land ho, they're getting ready to enter orbit too in just a couple of months. And Jupiter ho, much more to expect from both

of these missions. Emily, I look forward to talking to you again next week. See you then, Matt. She's our senior editor, the Planetary Society's Planetary Evangelist, and a contributing editor to Sky and Telescope magazine. Bill Nye is on vacation this week. I hear he's looking up at Mount Rushmore. So in a few moments, we'll be talking to Dante Loretta, another exciting mission that will get underway very soon this year, and that's OSiris-Rex. Asteroid Day is June 30th, the anniversary of that cataclysmic impact that obliterated the forested hills of Tunguska, Russia in 1908. We're celebrating a bit early with the return of University of Arizona professor and researcher Dante Loretta. Many of you will remember the great mission overview he provided

in our September 15, 2015 show. That mission is OSIRIS-REx, the Origins Spectral Interpretation Resource Identification Security Regolith Explorer. That may sound tortured, but the god Osiris is a pretty good role model. Ancient Egyptians believed he brought life in the form of agriculture to the Nile Valley, just as Osiris Rex may bring pristine samples of the building blocks of life on Earth to Earth-bound labs. But Osiris was also the god of the underworld, and we know that near-Earth asteroids like Bennu, the one that will be sampled by this mission, have and will again threaten our planet with destruction and death.

By the way, Bennu was yet another Egyptian deity associated with creation and rebirth. Dante, welcome back to Planetary Radio. Thanks, Matt. It's great to be here. As I told the listeners, we went through a lot of what the spacecraft has to offer, its fantastic suite of instruments, in the show that we did last September. Tell us where we are now. Your spacecraft is at the launch site, right? That's right. We achieved a major milestone on May 20th. We shipped the spacecraft from the

production facility at Lockheed Martin in Colorado. We flew on an Air Force C-17 Globemaster cargo transport plane, landed at the shuttle landing facility at Kennedy Space Center, and got our spacecraft into the new home, which we call the Payload Hazardous Servicing Facility, or the PHSF, at Kennedy Space Center. It's a facility that's got a long history. Many planetary missions have passed through that, and they have all their logos up on the wall, so it was really great to see everybody who had come before us. So they know what they're doing.

They do. It's actually our team that moves in. So it's the Lockheed Martin, the Goddard, and the Arizona team that move into the PHSF. Kennedy Space Center maintains it for us. But we take over and we do our tests and our preparations for launch there. I saw on your blog that you invited the Air Force crew of that C-17 to the launch. Yeah, they were great hosts. They were really friendly. They allowed us to go up into the cockpit and chat with them and learn more about the aircraft

and the other amazing missions that they fly, chat with them and learn more about the aircraft and the other amazing missions that they fly, which are in much more dangerous situations than transporting a spacecraft to Florida. And so they were really excited to be part of the program, and we made good friends with them, and we're happy to have them come down to Florida and wish us well on the beginning of our journey. I love those images of this big box with a spacecraft that's going out to visit an asteroid, moving down the road on a semi, too. It's pretty cool. Yeah, that was a little bit nerve-wracking.

They said we're going to keep it around 65 miles per hour, and I was like, okay, I think we're good. We did have a nice police escort and lots of vehicles in the promenade, so we were in good shape getting to the Air Force Base. It was also fascinating to read about the measures that you had to take, even when the spacecraft was in transit, in the interest of planetary protection. Can you talk about some of what you had to go through? Yeah, our mission is designed to return pristine organic compounds from asteroid Bennu, and so we do a lot of contamination control, contamination knowledge

to preserve our science. And the science requirements are actually much more of our driver than the planetary protection. We could have met the planetary protection with less stringent procedures, but the science drove us to even tighter control because not only worried about biology, we're worried about anything organic. And there's a lot more organic compounds floating around than there are biological species. So we had to keep the entire spacecraft under a dry nitrogen gas purge. So we had this big rack of gas bottles and valves and plumbing that went right into that shipping container and made sure that we kept the spacecraft clean throughout the entire journey. You came close.

I think 53 minutes once, and your limit on doing that purge was 60 minutes? That's right, yeah. So that was the stressing case when we had to transport the container off of the truck, onto the forklift, and then get it winched into the cargo bay of the C-17. And we had to get the purge cart in right behind it so we could get back on. And we had allowed ourselves a 60-minute budget for our contamination control requirements, and we got it on 53 minutes into the operation. Not bad. Must have been nerve-wracking, though.

We were watching the clocks pretty closely there. And, you know, there would be a lot of paperwork when you miss a requirement like that. So we certainly wanted to get it done and not to mention preserving the great science that we're going to do. All right. So now you're back in that nice clean room and everybody's wearing bunny suits. What's left to do with the spacecraft other than putting it on the tip of a rocket? Yeah. So we've done some final checkouts. The first thing you want to do is a verification test to make sure nothing changed just from the transport itself so that, you know, there was no shifting of components or anything like that. So you get it there, you check it out, say, okay, we got the same results we got before we left Colorado, so we're in good shape there. We had to install a couple of components. One element came in later

than scheduled, which was one of the LIDARs, which is a laser ranging device for our navigation and control systems. That went on the spacecraft. We also waited until later to put in the flight batteries, just because we don't want to stress those through our testing. So we ran with a series of test batteries, and now the flight batteries are on the spacecraft. And then we've got to install the fuel. We've got to install the ordnance, which are the explosive bolts for releasing the solar arrays. And then, of course, the critical gas that goes inside the TAGSAM bottles. Which is also nitrogen, right? That's right.

Nitrogen's kind of the standard gas that we use for curation, collection, and contamination control. If we figured we'd pick one, nitrogen's nice and inert, dry, there's a lot of it in the atmosphere. So that's the one we use for all of those functions. So you're looking good for the opening of this launch window in September? We are in great shape, yeah. We are on schedule, even a little bit ahead of schedule. The launch vehicle looks like it's going according to plan. We were on an Atlas V rocket. If you've been following launches, and I'm sure you do, the last Atlas V launch was to the International Space Station for a resupply mission,

and they actually had an anomaly where the first stage cut off early, and the second stage fortunately was able to make up for it. They had some margin on the second stage of the booster. You know, whenever something goes wrong like that, there's a huge investigation that kicks off. They've gone through all of the components on our rockets, as well as the ones that are in line ahead of us. Everything looks like it's been resolved there. We're going to anxiously watch the MUOS-5 launch on June 24th to make sure that one goes smoothly. You told us nine months ago, you've got a pretty long window, and you'd prefer to launch late in that window, because you said it might take as much as a year off of

off the mission. You'd get back these samples that much sooner. How is that looking? That's not going to happen. So there was a lot of things that had to go right in order to get that early return to occur. We would have come back in 2022 instead of 2023. One of the key parameters was what we call the dry mass of the spacecraft, which is basically the mass without any of the rocket fuel on board, which we call the wet mass. And the dry mass had to stay below a certain value. And one of the things we did when we arrived at Kennedy was a spin balance test, where we literally put the spacecraft on a turntable and spun it around, and we measured the center of gravity along that particular axis we call the z-axis. And that's a really

important parameter because all of our large engine burns on the main engines go through that vector, and we don't want to have an imbalance or you might get off course. So we had to put some ballast weight on in order to get the center of gravity lined up with where it needed to be. That ended up being about 20 kilograms of material, and that put us over the dry mass limit, which would have enabled the early return. And it's just another example that always fascinates me of the intricacy and the interdependencies of all these components and how they just ripple through the whole mission design. Someday we ought to talk about that and just what it takes to manage a mission like this, which is also a little bit of what you try to capture in your game, Extronaut,

that we'll talk about in a few minutes. Let's talk about your target, Bennu, which, of course, you got some help in naming that from a contest that the Planetary Society helped out with. Is it just a run-of-the-mill rock, or is there something special about Bennu? Oh, no. Bennu is a very special asteroid. We went through a long process to select the target for OSIRIS-REx to maximize the chances of mission success and the highest science value return for our program. So the early selection criteria were based on engineering design constraints, actually. We had some pretty basic ones. We decided early on that we were going to be a solar-powered spacecraft. That was dictated by NASA because radioisotope power wasn't available to us. And that meant we

didn't want to get too far away from the sun and be in a really power-limited condition. So we set the constraint there at about 1.6 astronomical units. And then we also decided we didn't want to have a complicated thermal control system. Classic example is the Mercury Messenger, where they had to have a giant sun shield and make sure they kept the spacecraft in the right attitude to keep everything functioning. We didn't want to get too close to the sun. So we set the inner distance at 0.8 astronomical units, remembering that the Earth is at one AU. So right away, just by setting those two ranges that dropped us down to a few thousand asteroids in the solar system. And then we wanted something that was relatively large. There's a lot of tiny asteroids out there on the order of two meters, 10 meters, 50 meters. And they probably don't

have any loose regolith on their surface, any of this loose soil that we want to grab and bring home. And many of them are spinning really rapidly. And that would make it very hard for our touch and go sampling maneuver. So we wanted something 200 meters or bigger, and that got us down to a couple of hundred asteroids. We also looked at the reentry. We're coming back into the Earth's atmosphere. We decided to use the Stardust return capsule because that was a proven design built by Lockheed Martin, our aerospace contractor.

And that has to come in at less than 12.4 kilometers per second re-entry velocity and that sets the inclination of the orbit that is the angle of the asteroid's orbital plane relative to the earth's orbital plane you can imagine as that angle increases the relative velocity goes up through simple vector math so that got us down to a few dozen asteroids and then we got to come in and say okay we want something that we feel has a high percentage of having carbonaceous organic compounds, providing us clues to the origin of life and the origin of the oceans on our planet. That got us down to five asteroids. And then we picked Bennu because it was so well characterized. We had a great astronomical data

set that really facilitated mission planning, and that was the final decision point for us. So it really narrows down. In fact, there's a great graphic about this that is sort of like a pyramid, and up at the point is this asteroid Bennu, and there just weren't that many to choose from once you got to that point. That's right. Once we laid down the basic engineering and then the science on top of it, that we were down to five targets. Principal Investigator Dante Loretto will tell us more about the OSIRIS-REx sample return mission and its asteroid target in a minute. This is Planetary Radio. This is Robert Picardo. I've been a member of the Planetary Society since my Star Trek Voyager days. You may have even heard

me on several episodes of Planetary Radio. Now I'm proud to be the newest member of the Board of Directors. I'll be able to do even more to help the Society achieve its goals for space exploration across our solar system and beyond. You can join me in this exciting quest. The journey starts at planetary.org. I'll see you there. I'll see you there. You know what? We could use your help. If you find anything we've missed, you can let us know. It's all at planetary.org. Thank you.

Welcome back to Planetary Radio. I'm Matt Kaplan. Dante Loretta leads the OSIRIS-REx mission, launching for near-Earth asteroid Bennu in September of this year. launching for near-Earth asteroid Bennu in September of this year. With asteroid day fast approaching, I knew Dante could tell us much more about this 500-meter-wide target and its hundreds of thousands of cousins in the asteroid belt and elsewhere across our solar system. How is it that we know so much about this asteroid Bennu? Well, it's in a very Earth-like orbit, and it's got an orbital period of 1.2

years, and the Earth has an orbital period of one year. And so every six years, they're in the vicinity of each other in the solar system, and it does very close approaches to our planet. It was discovered in 1999 by the Linear Asteroid Survey based out of New Mexico. And right away, the science community recognized it as an outstanding radar target. And so the planetary radar system, which has access to the Arecibo Planetary Radio Telescope and the Goldstone Radio Telescope, they got on it right away, and they got us unprecedented resolution of the target, giving us information about the shape and the rotation state and even some geology in terms of average grain size on the surface and radar roughness of the surface.

We also got spectral data, which confirmed that it was a very low albedo, meaning a very dark black object, and therefore likely to be rich in organic compounds that are the prime objective of our mission. We had a lot of observations of its position. So its orbit is, in fact, the best constrained orbit of any object in the solar system, even the Earth. And that's because we have so much information, including three radar ranging measurements spread over a period of 12 years. The uncertainty in the semi-major axis, over a period of 12 years, the uncertainty in the semi-major axis, which is the average distance between the asteroid and the sun, is six meters out of over 100 million kilometers. So the decibel

points just boggle the mind for those of us who are used to evaluating significant digits in our science results. So we know where this thing is really well. So we know where it is, results. So we know where this thing is really well. So we know where it is, we know the size, the shape, the rotation state, and we have a pretty good handle on the composition. All of those met our requirements for the science of this mission very well. So we're going to post a link, of course, to the OSIRIS-REx website where you can see this radar image, or maybe more than one, of asteroid Bennu. I'm happy that this came up, because of course, the great dish at Arecibo that has done so much of this work is in some jeopardy. And in fact, we're going to have a conversation with somebody observing a different asteroid at

Arecibo next week, a little Planetary Radio Extra conversation for this show. Sounds like this capability has been pretty important to your planning. Absolutely. I mean, it provided the fundamental information about the size and shape and rotation of the asteroid. And using that information, we're able to really plan the mission in very great detail. We can estimate what it's going to be like to orbit the asteroid. We can use it for observation planning so that we can understand the challenges and the excitement that we'll get when we're trying to target specific regions on the asteroid surface. We're able to use that information to estimate

the geopotential, that is basically where are the valleys and where are the mountains on the asteroid, and the valleys being the regions where we expect the regolith to be accumulating and where we're likely to go get our samples. So it's a fundamental input to what we call our environmental requirements document and our mission planning teams because they use it to verify to the agency that we in fact have the high chance of success that is required for a program like this. Even though we've talked about it in the past, and I'm guessing that most of our audience understands why sample return is so important, tell us why not just do everything remotely with instruments? I mean, you've got a great suite of instruments that'll be reporting back in situ. Yeah, so the primary objective of OSIRIS-REx is to bring back samples

of a carbonaceous asteroid that represented the kinds of objects that we believe seeded the surface of the Earth with the building blocks of life. And so we need to go in and perform exquisite, detailed trace analysis of these compounds. And you really can't get that done on a spacecraft. Some of the instruments that we're going to use, like the synchrotron x-ray probe, require enormous facilities on the ground to get the spatial and the chemical resolution that are required for our science. So we really have to have samples in the laboratories to meet our primary science objectives. Not only that, sample collection is a

treasure trove for the future. The capabilities of material science and chemical analytical instruments is going to continue to improve. I've seen it able to get pieces of Bennu, get it into their laboratories, and perform investigations that we never even dreamed possible here at the beginning of the 21st century. Something occurred to me a few days ago. I told you about this in email, and it's sort of the analogy between studying asteroids and the public feeling about sharks on this planet, but a lot of the public anyway. I'm almost surprised that the Discovery Channel doesn't have a scary asteroid week, just like they have shark week. I actually think that's in the works. Is that right? Yeah.

All right. Well, I guess I should sue them. But just the same, they are a threat, and you will be doing some of your studies will have to do with that, right? Absolutely. I mentioned earlier the criteria that went into selecting the target, which were things that didn't get too far away from the Earth, things that were on a low inclination relative to the Earth, basically meaning something that we could launch a spacecraft from our planet, rendezvous with, and then get back to our planet. When we leave Bennu, we have to do a burn on our main engines for the rocket system. And that changes the velocity of the spacecraft by about 200 meters per second. And that single burn sets us on a trajectory that will intercept the Earth in 2023,

about two and a half years later. But what that means is you only need to change the velocity of Bennu by 200 meters per second to put it on that same trajectory. So it's already coming very close to the Earth in energy space, delta V space. As we integrate out over the next couple hundred years, there's a reasonably high probability that Bennu is going to end up as an Earth impactor. We can predict its orbit. I mentioned earlier that we have a very precise measurement of the orbit of this asteroid, and we can predict it with great certainty to the year 2135, so about 120 years into the future.

At that point, it's going to come in between the Earth and the Moon, and the solution scatters. Our equations don't have an exact answer just because when we propagate the uncertainty in the asteroid position, as small as it is, it still has a variety of possible futures that can come out of that encounter with our planet. Many of those lead to a return and an impact with the Earth. So I look at a lot of what we're doing on OSIRIS-REx as a gift for the future. We don't know if it's going to hit the Earth or not, but the people of 2135 will know if Bennu's going to hit the Earth. And I guarantee you, they're going to be very grateful for not only the data that we collected

of the asteroid, but the samples that are back on Earth, because they're going to be able to go to all of that information and figure out how to prevent this thing from potentially hitting our planet. Well, it's nice to make those error bars, put them closer together when it's a matter of life and death. That's right. I always joke, I wish I could live to the year 2135 just so I could see what my citation index looks like. Before we finish, tell us a little bit more about that game Extronaut.

It's been a while coming, but it's getting close. Yeah, we've made great progress. I do want to thank all of our Kickstarter backers, including yourself. Thank you very much for the campaign. We ran that in October of 2015, and we attracted almost 1,000 people to that Kickstarter, and it was great. And we went through a design cycle. I applied a lot of the engineering principles that I use for Osiris-Rex to making the game really well, including extensive peer review. And we got the final files to the factory early this year and went through the whole approval process, got the proofs, and they are now

on their way to the United States and they'll be available for purchase in July. So we're very excited to see that product get to market finally. Fantastic. Congratulations on that. Let's finish with this. Would you like to say something about Michael J. Drake? Yeah, thanks for that opportunity. Mike was a really special person to me and to the OSIRIS-REx team. He, first of all, hired me at the University of Arizona back in 2001. He was the chairman of the department and the director of the Lunar and Planetary Laboratory. So I owe him my job. And then he took me under his wing. And in 2004, he invited me to be his deputy for the principal investigator position on an asteroid sample return mission. And we worked really hard for seven years to write proposal after proposal to NASA.

You never get it the first time in this business. You always have to go through several iterations. And we won the contract for OSIRIS-REx in May of 2011. Mike, unfortunately, passed away in September of that year. So he did get to see us win, and he was there when we celebrated. But it was a major blow to the team and to me personally. I lost a great friend and a great mentor, and it's hard to talk about even now. But his vision lives with us to this day. Mike was very dedicated to the science of OSIRIS-REx. He loved asking big-picture questions like, where did we come from? And he also believed heavily in investing in the future, and especially in educating the next generation of scientists, engineers, and managers,

and all the other great talents that come together to make a program like this a success. And we've carried that forward. We've had a lot of students work on this program. We have a student-built instrument, our X-ray imaging spectrometer, and I believe we've already made a large impact in workforce training. And I've seen a lot of leaders grow up in our program, and we can expect great things from them as planetary science continues its path into the future. Well said, Dante. A pleasure to talk to you once again. Can we do this in, oh, let's say maybe three, four months when you've got a spacecraft on its way to Bennu? Absolutely. Are you guys coming out to our launch?

I know the boss is. I know Bill is. I would love to, of course. I have to convince them that that's a good investment, that they need the radio guy there. All right. Well, let me know. We could certainly do something right around that time or certainly after we're in space and we've gone through our checkouts. I would love to. I look forward to it, Dante, and I hope things continue to go as well as they have been.

Thanks again. All right. My pleasure. Dante Loretta. He is the principal investigator for OSIRIS-REx, preparing right now at Cape Canaveral to be launched toward asteroid Bennu. He is a professor of planetary science and cosmochemistry at the University of Arizona's Lunar and Planetary Laboratory.

I don't think there's too many people on this planet who know more about near-Earth asteroid formation and evolution, and his mission is going to help us learn much, much more about those topics. We'll learn a few things from Bruce Betts, too, when we go to this week's edition of What's Up. Time once again for What's Up on Planetary Radio. Bruce Betts is at the other end of the Skype line, ready to tell us what's up in the night sky. Not sounding quite as good as usual because he's not using his usual microphone,

but welcome anyway. Thank you. You sound wonderful, like you've got a quilt over your head. Yes, well, that's easily explained. I have a quilt over your head. Yes, well, that's easily explained. I have a quilt over my head. We're doing a little remodeling of the house here, and the carpets are gone. The wall-to-wall carpet is gone because no one wants a house with carpeting anymore. So are the bookcases.

So all the good acoustical stuff is gone. So here on what is by far the hottest day in the Los Angeles area in ages, I have a quilt over my head. That's genius. I just love that image very much. Thank you. Thank you very much, too. All right, what's up?

Get on with it. Well, when you go out at night, which is, you know, about 95 here, you can in the evening still see Mars. It is dimming, but it's still brighter than any star in the sky, though not brighter than Jupiter. Mars is in the evening south looking reddish, and Saturn, which is gradually getting farther away from Mars in the sky, is yellowish, much dimmer, closer to Mars than Saturn, is reddish, and Terry's a dimmer but still bright red star. That's the party. Oh, I'm sorry.

Make sure you check out brighter Jupiter over in the towards the west, southwest in the early evening. That's dominating over there. We move on to this week in space history. It was 2004 when Spaceship One became the first privately funded human spaceflight on a sort of suborbital flight. Yep. I was there. What a blast. I get it. So on to...

Random spaceflight. I forget. The mass of all the asteroids in the asteroid belt added together is still only about 22% the mass of Pluto. I'm always amazed to reflect on how little stuff, there's a million objects, but they're all little, how little stuff is actually in the asteroid belt. That's fascinating. And we'll see that Pluto is not that big when we get to the trivia contest for next time.

Let's go to the previous trivia contest. And I asked you how many NASA field centers are currently named after former astronauts? How'd we do, Matt? Very nice response to this. People going after a Planetary Radio t-shirt, a, wait a minute, I got to get right, a Rubber Planetary Society asteroid, and a 200-point itelescope.net account on that worldwide network of telescopes based in Australia, but they've got scopes all over every hemisphere that you can imagine. The winner this week... I imagine some on Mars, is that...

Not yet. Give them time. Skip Medlock, a first-time winner, as far as I can tell, in Lubbock, Texas. He says that there are two NASA centers named after astronauts, John Glenn Research Center and the Neil Armstrong Flight Research Center here in California. Is he correct? That is correct. Excellent. Well, Skip, you're going to be getting

all of that cool stuff, and somebody else is going to get the same prize package this week. But I put them in order. Are you ready? Here are the NASA centers. Ames, Armstrong, Glenn, Goddard, JPL, Johnson, Kennedy, Langley, Marshall, and Stennis. Order them in latitude. and Stennis. Order them in latitude. Maybe next week. Martin Hajofsky in Houston, Texas. He said, how long must we Planetary Society members wait to get JPL, the only NASA field center without a person's name, rechristened in honor of Bruce Murray? But then he adds, or Bruce Betts for that matter. Yes. I mean, no, it should be Bruce Murray. That is a brilliant idea, the Bruce Murray part.

I like it as well. I think listener Paul Code in Los Altos, California, might be confused. He thinks it already is named after someone. He refers to it as the Joan Jett Propulsion Laboratory, which, you know, I like her a lot. I think that'd be a nice tribute as well. Me, yeah, me. Always move on.

Rockets in space. Moving on. All right, we move on. We compared Pluto to the asteroid belt, saw that Pluto is a lot more massive than those pesky asteroids, but how does Pluto stack up compared to the moon? What is the ratio of the mass of the moon to the mass of Pluto? How much more massive is the moon than Pluto approximately?

Go to planetary.org slash radio contest. This time you have until Tuesday, June 28th at 8 a.m. Pacific time to get us your answer. And I think we are done. All right, everybody, go out there, look up on the night sky, and you just have to think about Matt with a quilt over his head. Thank you and good night. It's really toasty in here. He's Bruce Betts, the director of science and technology for the Planetary Society. in here. He's Bruce Betts, the Director of Science and Technology for the Planetary Society, and he will join us again next week, probably with a better microphone, here for What's Up.

I wonder what's on the quote. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its impactful members. Josh Doyle composed our theme, which was arranged and performed by Peter Schlosser. I'm Matt Kaplan. Clear skies.