Planetary Radio: Space Exploration, Astronomy and Science - Leaders of the Lucy asteroid mission

Episode Date: October 13, 2021

A delightful, exclusive conversation with principal investigator Hal Levison, deputy principal investigator Cathy Olkin and deputy project systems engineer Mike Sekerak on the eve of Lucy’s launch toward the asteroids that share Jupiter’s orbit. Don’t miss the cameo appearance by Ringo Starr! Bruce Betts offers another What’s Up space trivia contest with an extended deadline. Learn more at https://www.planetary.org/planetary-radio/2021-lucy-levison-olkin-sekerakSee omnystudio.com/listener for privacy information.

Leaders of the Lucy mission that is about to begin its journey to Jupiter 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. I lied. Lucy is not going to Jupiter. I lied. Lucy is not going to Jupiter. In fact, it will never be closer to Jupiter than when it returns to Earth in a slingshot maneuver. That's how far the Trojan asteroids that share Jupiter's orbit are from our solar system's biggest world. Our last conversation with Hal Levison, Kathy Olkin, and Mike Sekarac was over two years ago. Now their spacecraft is prepped and ready to begin the long trip to the outer solar system. My exclusive and very fun conversation

with them is minutes away. It includes a cameo appearance by a space fan named Richard Starkey. You may know him as Ringo Starr. Afterward, we'll check in with Bruce Betts, who has a space trivia quiz with yet another extended deadline. We'll begin with these headlines from The Downlink, the weekly newsletter from the Planetary Society. You can get it for free at planetary.org slash downlink. The October 8 edition is topped by a photo you'll hear Bruce and me talk about. is topped by a photo you'll hear Bruce and me talk about. It's Mercury, imaged during a brief visit by the European Space Agency's BepiColombo spacecraft while it was less than 200 kilometers above the surface.

Five more of these encounters are in store before it finally achieves orbit in four years. Building on its very successful Emirates Mars mission, also known as HOPE, the United Arab Emirates has announced that it will send a probe to explore several asteroids in the main belt before finally landing on one in 2033. I look forward to welcoming back Her Excellency Sarah Al-Amiri, Chair of the UAE Space Agency, for a conversation about this new project.

I didn't hesitate when I received an invitation from Mike Sekirak a few weeks ago. He wondered if I'd be interested in getting the gang together again. Based at NASA's Goddard Space Flight Center, Mike is the Deputy Project Systems Engineer for the Lucy mission. Mike, Lucy Principal Investigator Hal Levison, and Deputy Principal Investigator Kathy Olkin were my guests in April of 2019, when their spacecraft was still coming together. Now Lucy is sitting on top of the Atlas V that will help it begin its 12-year mission. The launch window opens on Saturday, October 16th. It was just a week before that the four of us gathered online for the illuminating and very enjoyable conversation you're about to

hear. Hal and Kathy, both of whom work at the Southwest Research Institute, gathered with Mike around one microphone at Cape Canaveral. Hal, Kathy, Mike, congratulations on reaching this already auspicious date. I cannot believe that we are talking, well, as we speak, it's still, what, nine days ahead of the opening of your launch window. But I'm so glad to catch you now because I have seen some of your schedule for next week, just the public and media events you're going to be doing. And so I'm glad to catch you now when you've got a moment to catch your breath and talk to us on Planetary Radio. Welcome back to the show. It's our pleasure to be here. Thank you. You've got to tell people what you just told me, what just happened this morning as we speak on the 7th of October.

Kathy? This morning, it was really exciting. We woke up early and got to see the spacecraft lifted onto the booster at the Vertical Integration Facility. So amazing. What an amazing day to finally get here and have our spacecraft on top of the launch vehicle.

Absolutely thrilling. I did see the two pieces of the fairing as they were being put onto the spacecraft. That was in one of the photos NASA was released just the other day. I'm so sorry I wasn't recording when you first told me that because you were just jumping up and down in spite of the fact that you've been up since when? We got up around four o'clock to head out to see it. They drove the spacecraft from Astrotech on surface roads, which is why they do it in the middle of the night, to get it to KSC. And then starting at around 7, they were beginning the lift.

Yeah, and you mentioned the encapsulation. The spacecraft was put into the fairing. It was a little bit of a bittersweet moment. I, you know, I love being able to see that spacecraft and I know that we're not going to see it again. You know, it's going to go on its way. And, and I was a little sad about not being able to see it in person again. Of course, you know, Lucy will be where it needs to be in space where it's designed to be. And of course, where it can capture all the great science. But still, I felt a little sad about not being able to see it in person anymore.

Yeah, we did our final checkouts last week. We got to inspect all the blankets, all the instruments, every little fine detail, and we all put our stamps of approval on it and wished it goodbye. We do our first power-up on top of the rocket tomorrow for our final checkouts, and then we're ready to go. Wow. And you were not the first people to tell me that was kind of a feeling of mixed emotions as you saw your spacecraft with your own eyes for the last time. So, Mike, it sounds like everything's in good shape. Yeah, absolutely. Technically, the spacecraft is ready to go. We put it through a lot of environmental testing and a lot of other simulations and other verification procedures throughout the whole last basically year, year and a half, all the way through the normal shock and vibration and thermal vacuum testing.

But because of our unique mission, we've had to do some unique tests to help simulate those asteroid encounters and flybys, which is required to really look at the loose, unique aspect of our mission to define and to execute some specialized testing. And the spacecraft all passed with flying colors and we feel she's ready to go. Yeah, I'd like to mention one of those specialized tests. We have an instrument pointing platform on the spacecraft. tests. We have an instrument pointing platform on the spacecraft. It has our scientific instruments and it has a two axis gimbal so we can move and point at the Trojan asteroids as we fly by. That gimbal, of course, is designed to be working in space, but we need to test it here on Earth. And so there's a huge helium balloon that we use to off-weight the force of gravity pulling down on the instrument pointing platform so that we can do deployment tests. I think that's really cool. All the different ways that there's ground support equipment to be able to test the spacecraft on the ground that's meant to work in space.

Yeah, and another one of the really amazing tests was when we deployed these solar arrays. The largest ultraflex arrays that have ever flown will be the furthest solar-powered mission that's ever operated. And seeing those arrays deploy off the spacecraft for the first time was really, really exciting. But it takes a huge amount of ground support equipment. And we only can deploy one wing at a time because it's so big, you know, fitting into that area. But they worked just great so far on the ground.

And we have confidence that they'll work in flight as well. It was quite the engineering feat to get them tested both in the vacuum chamber on their own as well as on the spacecraft and test it on the ground. I just want your audience to understand what these solar arrays are. They're made out of cloth. Well, the cells aren't made out of cloth. But the support is made out of cloth. Well, the cells aren't made out of cloth, but the support is made out of cloth and they unfold like oriental fans. So they're actually quite beautiful to watch deploy. I encourage your listeners to go off and watch some of the videos that are on YouTube.

It really is quite beautiful. We will put a link to that video of the test deployment of those magnificent solar panels, those fans, on this week's show page at planetary.org slash radio, along with some other stuff that I think we'll be talking about. So you're going to be taking that record away from Juno, the current record holder for farthest stout flight by a solar-powered spacecraft. Tell me, if you had had the chance, if NASA had said, hey, look what we found, here's a radioisotope thermal generator we forgot we had, would you like to substitute that for your solar panels?

I don't know, Hal, might you have tried to take advantage of that? I mean, assuming it was years ago. Yeah, and it depends on the details, right? One of the things that are really special about our solar arrays is we got a lot of power for the mass, right? And so that's not necessarily true for any kind of nuclear power. So we'd have to look at the benefits, the cost benefits of it. Yeah. So our arrays are going to produce half a kilowatt of power all the way out at 5.7 AU. That's why we have the big solar arrays. And so one RTG won't be nearly enough to give us that

amount of power out of that distance. Isn't that amazing? I mean, we went from, oh my gosh, is Juno going to be able to do this from so far out, to now actually seeing other advantages, not just the poor availability of RTGs, but they may actually offer the advantages that you're talking about. One other aspect of these things is when they're folded up, they're only four inches thick. So that gives you some feeling for how special these things are and how innovative they are. I wanted you to know that all of us at the Planetary Society were ready a couple of weeks ago to start screaming if the budget circus in Washington, D.C. had prevented you from beginning your mission within this launch window that opens on the 16th. Now, thank goodness that that worked out. But were those anxious moments for any of you as well, Kathy? Well, it was something that we had our eye on, but we were planning and putting contingencies in place

and trying to figure out how we would best work around things if we needed to. So it was something to pay attention to, but I wasn't worried yet. And luckily, it didn't end up being something that we had to worry about. I was pretty confident that we would be okay. The people at headquarters are supporting us every which way they can. And I'm pretty certain that they would have gotten those exemptions and whatever we needed to do to finish our job. They really were on top of all that. I would like to think that someone told all the members of Congress we might have to delay the Lucy mission. And they said, what? We can't have that.

We already had one other government shut down during earlier part of our development. And then, of course, we had to deal with COVID obstacles. So to get so close to the end, to be tripped up by this, we were going to make sure that didn't happen. Well, just like we've done all along, you know, things have come up. We work around them. We make plans. We look at our contingencies and we move forward because it's not like we haven't had challenges. Of course, being in ATLO during COVID was challenging, and we are here and on track for the opening of our launch period. So I'm confident because

we've had a lot of experience in working as best we can to stay on track. If you don't mind me saying, our team has been amazing. The innovative way they had to look at scheduling and budget during COVID, the flexibility every day, they had to replant things occasionally, and yet they got us here where we needed to be. They're really an amazing group of people. Yeah. And we had a plan at first when COVID happened and it was the fast plan. And then we had the faster plan. And then the next plan, you might think it would be the fastest plan, but no, that's when we pivoted to peace and love. Peace and love. Well, that's going to come up in a few moments as well. Hal, this may be as good a time as any to let you give some additional kudos to, if not the individual members, other members of the team, but the other organizations and companies that have helped us reach this day. Well, there's no doubt that we have gotten a tremendous amount of support from our partners. They've been there not only with financial support when we needed it, but every time that we needed help, we got the A-team. And that is why we ended up being where we are. So it's a combination of Goddard Space Flight

Center, who's been managing this, and Lockheed Martin has been amazing at getting all this done in time. It's been a great collaboration that has allowed us to get here. Yeah, and I'd like to also call out some of our other partners. Our instruments were built at Arizona State University and the Johns Hopkins Applied Physics Laboratory and Goddard Space Flight Center. And our navigation team comes from Kinetics. And our science operations center is at Southwest Research Institute. So it takes a number of different institutions all across our country to be able to build and fly a spacecraft. And it's because of all the hard work of the people at those institutions

that we are where we are today. A great collaboration as so many missions, basically all of missions are nowadays. You couldn't do something like this without a collaboration like that. Yeah, it takes a great team, right? There's no single person who could build and fly a spacecraft.

You know, that would be crazy. But it also takes a lot of people with different talents and different skills all coming together for a single goal. That's part of the reason I love doing space exploration. I promise I'm going to come back to the mission and what's ahead, even though we've talked about that in the past. By the way, you were last on the show in April of 2019, so two and a half years. A lot's happened since then. There are so many other wonderful things that are wrapped around this mission. I watched the video the other day made of the dedication ceremony

for the plaque that has now been attached to Lucy and is going to sail with Lucy for, what, tens of thousands of years? Or longer. Good. Or longer. So our estimates is if Lucy is left alone, that its average lifetime before it either hits the sun or gets ejected from the solar system is roughly 2 million years. Wow. You know, we had this thought. You know, we go back to the pioneer plaques.

Remember those back in the 70s? I was in middle school, right? And I remember thinking how cool that was. Made me feel like I was connected to the galaxy in a way that I'd never thought of before. And it probably had a lot to do with why I'm doing what I'm doing today. The Pioneer plaque is heading out to the stars, so we put messages to aliens about the human race on that here, since it's remaining in orbit around the sun for such a long period of time. It's easy to imagine that some astroarchaeologist sometime in the near or distant future will come across it looking for our junk, trying to learn about us. So this plaque has inspirational messages to our descendants on it.

It's really an honor to be able to do that. We're leaving a record. I mean, if you look at most of our lives, even the three of us, this thing is going to outlive everything that we've done. And so it's really our legacy that's sitting on that spacecraft. Yeah. And I really like thinking about the long-term, those eons that you're talking about, right? I think it takes a long time to explore the Trojan asteroids, we'll be in flight for 12 years. But that's nothing compared to the millions of years that the spacecraft could go on. And also, it's nice to look back to the Australopithecus fossil, Lucy. That was millions of years ago as well. And so we're spanning millions of years in either direction. And hopefully when our descendants go and find Lucy in the plaque, they'll say, oh, it's based on the fossil that we know from our ancient records. So that would be very cool. But, you know, millions of years is a long time.

One of the really charming things about that ceremony that we will link to, as I said, is, you know, the synergy between Lucy, the fossil and Lucy, the spacecraft. You know, he has an interesting story to tell. His hypothesis is that what makes human beings human is our ability to be able to collaborate so that as a group, we can do, accomplish things that are greater than any individual can do. So that's his definition of human. And in that way, what we're doing, building a spacecraft, is sort of the ultimate expression of that. That's just perfect, isn't it? Yeah, it really is.

Yeah, and I'm really excited to take the Lucy spacecraft to go explore the asteroid Donald Johansson. When we were doing the mission design, there was an opportunity to fly past an asteroid, and that asteroid, you know, had its typical license plate designation, not a given name. We realized the opportunity and asked the person who discovered that asteroid, Bobby Buss, if he could name it after Donald Johansson. And now it is asteroid Donald Johansson. So we'll be taking Lucy out to visit Donald Johansson. That's just wonderful. I want to go back to the plaque. It includes these wonderful, wise messages from, you know, people like Einstein and Carl Sayen, poet Rita Dove, novelist Kazuo Ishiguro, I'm a big fan, and many others. Even Amanda Gorman,

who blew so many of us away with the reading of her poem at the presidential inauguration earlier this year. And then there's this, I'll read it, from the wonderful Davis O'Bell, who I was in touch with a couple of days ago. We, the inquisitive people of Earth, sent this robot spacecraft to explore the pristine small bodies orbiting near the largest planet in our solar system. We sought to trace our own origins as far back as evidence allowed. Even as we look to the ancient past, we thought ahead to the day you might recover this relic of our science. Gosh, she's great. She's just wonderful. She is great. Beautiful words. Yeah. How did you choose among all of the possible candidates to basically make very nearly immortal on this plaque? I must admit, it was just coming up with the type of person we would like to represent us. We've reached out to Nobel laureates. We reached out to U.S. poet

laureates. We then just started coming up with a bunch of names that we thought would really represent us well. Dana came to the front of the list really quickly because she understands what we're doing so well, right? A lot of the people on that list, while they think what we're doing is profound, they really don't understand very well the community that we're part of of and i've always been impressed with dana with her ability to be able to truly understand what we're doing and why and her words reflect that yeah david's books are just amazing and the way that she can convey the science and exploration and i'm thinking of longitude and, you know, that is just amazing.

And so she really brought that insight with that quote, but we, there are so many people who come from different backgrounds and it was wonderful to see their take on this request. Yes. And the other, on this request. Yes. Another group that we've included is we reached out to people from the pop culture. Pop culture. I got one for you.

Let me see if you can hear this. A little noisy, but I'm so excited. Lucy is going back in the sky with diamonds. Johnny will love that. Anyway, if you meet anyone up there, Lucy, give them peace and love from me. Peace and love, man. Peace and love. The one and only Ringo Starr.

You actually had, you have messages on the plaque from all four of the Beatles, speaking of pop culture, pretty, pretty darn cool. Well, after all, you know, the spacecraft is named after the fossil, right? And the synergy there is, you know, Donald Johansson and his collaborators were trying to unravel the history of the human race with the fossil. We're trying to unravel the history of the solar system, both of which are origins questions, with the spacecraft. The castle was named after the song Lucy in the Sky with Diamonds. So there is a connection there. And if you look carefully, you'll notice that our logo for Lucy is diamond shaped.

Oh, I have it. So we're making a connection there with that. So they were natural to reach out to when we were putting the plaque together. And, of course, the living ones got very excited about being able to contribute, as you heard from Ringo. So let's talk about the mission, which we've done before, but it bears repeating. So seven asteroids, five flybys you just mentioned to me. Some of these are double or binary asteroids. There's a lot to see out there. Remind us why these objects have generated so much interest from scientists in so many

fields. Kathy? Well, it's really interesting to understand the diversity of the Trojan asteroids. And that's really where we started, with a list of asteroids that had similar properties, so similar sizes, similar inclinations, but different spectral types, telling us that the composition was different. And then starting with those matched pairs, finding sets that the mission designer could get to. And that's how we got to Euripides and Oris in our mission design. That was the first objects that we started on, and then we built from there.

That was the first objects that we started on, and then we built from there. With Patroclus and Manetius, we were looking at what would happen when we continued the trajectory out further. Right, Hal? Yes. So the amazing thing about our trajectory, and let me just say, Kathy had it exactly right, that we started off looking for pairs. It turns out that that was difficult enough to find a pair of asteroids we could go to. The fact that we have such a large number is a combination of hard work by the team that designed the trajectory and a lot of luck. For example, our last one, which to me is the most interesting scientifically, which is this near

equal mass binary, just so happens that we happen to be floating by at the right time to be able to visit it. And so that luck really has led us to this amazing set of objects that allow us to compare not only spectral types, which is what we were set out to do, but a wide range of different directions and parameter space. We have everything from an object that's less than a kilometer up to objects that are a hundred kilometers across. We have objects that have very different collisional histories. We have an object that we know was involved in a major collision, right, because it's part of an asteroid family. And the binary, we believe, is pretty pristine and has been left alone. So we can, by seeing this multidimensional space, it really makes

the science that much more compelling. Yeah, and I'd like to build on what Hal was saying about the luck before, because with Patroclus and Manetius, they're on an inclined orbit. And so it just happened to be that not only were we drifting by at the right time, but Patroclus and Manetius were crossing the ecliptic plane or nearby at that time, allowing us to get to them. So there was a lot of luck in getting this amazing set of diverse Trojan asteroids. There was a lot of luck in finding the opportunities. The flight dynamics team has been spending a lot of server time over the past four and a half years, crunching this trajectory thousands and thousands and millions of times to be able to fine tune it. We have three

earth gravity assists, five deep space maneuvers, over 30 trajectory correction maneuvers in order to thread the needle, to do these flybys at just the right distances to make sure that we're able to get the, the, the other images and the science that we want to get. So it has taken that flight dynamics team a lot to make sure that we have robust, have accounted for all the unknowns because we're going to them because they don't know what they look like, which also means there's other challenges that we don't know exactly what's out there. So we have to look at the statistical variation to make sure that we are well within the margin of the spacecraft, which we comfortably are.

But from that first luck of finding those and then really, really drilling down into those details and putting all that in simulations and putting that on board the spacecraft and testing it, has taken a whole team from the engineers and the scientists as well, working together of, what do you know about the targets? Okay, let's take that and put that into the simulation. That has taken a lot of effort for that to converge, but it has. Yeah, exactly. And some of those details are really interesting, at least to me. We do a deep space maneuver as we're leaving the L4 swarm that targets our third Earth gravity assist, which sets us up then to fly by Patroclus and Manetius at the time that we want.

And so this is all carefully orchestrated, as Mike was saying, and really quite an accomplishment of mission design. Another part of that that I find so intriguing as a big science fiction fan is we'll be the first mission to go all the way out past Jupiter distance and come back to the Earth. And come back! You read all these books about humans crisscrossing the solar system, and it's all science fiction. We sent these probes out to great distances.

We'll be the first one that goes out and comes back when we do that third Earth gravity assist to set ourselves up for the Petrocos-Menezes binary encounter. You know, some of the people who found the trajectories, those magical trajectories that resulted in the grand tour by the two Voyager spacecraft, are still around. And they went through some of this, you know, these long nights of sweating over the numbers. Computers are a little more advanced now, fortunately for you guys. But you have to be thinking of Voyager, which to some degree, with this ballet that Lucy is going to be doing, it appears to me that in some ways you're actually outdoing the Voyager spacecraft,

at least in terms of trajectory. Now, I know that sounds like sacrilege, but still, it is a wonder to look at this path. So, obviously, the grand tour for Voyager, you know, visited all these planets and gave us these great images to help understand, you know, what these large bodies in the solar system look like. You know, what they had to do with inventing a lot of that when they did was truly amazing. You know, computers and our knowledge of celestial mechanics has improved since then, but our targets are so much smaller. So, it's so much harder versus a of that when they did was truly amazing. Computers and our knowledge of celestial mechanics has improved since then, but our targets are so much smaller. So it's so much harder versus a big planet versus an asteroid that at most is a little over 100 kilometers across to our smallest ones,

as Hal was saying, Palomelius, 20-ish or so kilometers across. That's a much, much finer needle that you need to thread there. And we want to make sure we get just to the right aim point to be able to do this careful choreography of actually imaging those asteroids. So it is a much finer window that we need to hit to image a small asteroid versus a large planet, not to take anything away from the Voyager mission, which is, I think, one of the most amazing missions. But we have new technology. We've used that to be able to do this really, really fine work. Stick around. Hal, Kathy, Mike, and I will have much more fun talking about the Lucy mission in just a minute.

Hi again, everyone. It's Bruce. Many of you know that I'm the program manager for the Planetary Society's LightSail program. LightSail 2 made history with its launch and deployment in 2019, and it's still sailing. It will soon be featured in the Smithsonian's new Futures exhibition. Your support made this happen.

LightSail still has much to teach us. Will you help us sail on into our extended mission? Your gift will sustain daily operations and help us inform future solar sailing missions like NASA's NEA Scout. When you give today, your contribution will be matched up to $25,000 by a generous society member. Plus, when you give $100 or more, we will send you the official LightSail 2 extended mission patch to wear with pride. Make your contribution to science and history at planetary.org slash S-A-I-L-O-N. That's planetary dot org slash sail on. Thanks.

Mike, I know you did some pioneering work on electric drives, ion engines, basically. I was just talking about a week ago on this show with Mark Raymond, who did so much with the Dawn mission with that because of its ion engines. You don't have that. I mean, I want to make sure everybody understands. Yeah, of course, you've got thrusters to make some adjustments now and then, but you don't have a main engine, much less an ion engine, that's going to make sure you thread the needle, as you're saying. And yet, this is all looking pretty good.

Do you wish you had an ion engine strapped on there? Well, as an electric propulsion person, of course, I always want to put one on there. But Hal said no. When you've got big arrays like this that can produce in Earth orbit, tens of kilowatts of power if we had restrung the solar cells differently. Yeah, 500 watts. Getting that to work at 5 AU is almost impossible. Yeah, you have to have a very throttable drive, which engineers and my friends and colleagues are working on.

But we are able to, just with the trajectory we're able to do alone, the thing about Dawn is that they did over 12 kilometers per second at delta V change using these NSTAR ion engines. And that's really amazing to allow them to change things in orbit. They weren't really using a lot of gravity. They were using that impulse from those ion thrusters. Whereas for us, we're only doing about 1.7 kilometers per second at delta V. A small correction, we do have a main engine, a Liris 1C Biprop engine that will be doing those deep space maneuvers. It's a chemical propulsion system to give those burns, which does the major orbit tweaking.

But we do have a main engine. But it's really the orbital mechanics that's allowing us to get the verses. So we don't have a lot of flexibility. For example, we are launching here shortly, and it puts us on one-year Earth gravity assist, and then two years later, another Earth gravity assist. If for some reason we don't go here shortly, which our team is all saying,

if we have to launch next year. Don't next uh the next opportunity would launch us in what would have been our first earth gravity assist to get us on the exact same trajectory um so that that's how special and unique this trajectory is so ion engines would definitely enable more options here, but we managed to find this trajectory that we are getting on. Yeah, and that's what I think, is that we found a solution to all of these design challenges that we had within the technology constraints that we were working in. And so, I wouldn't change anything. I wouldn't want to change the propulsion system. I wouldn't want to change the power system because we managed to find this beautiful solution. I mean, Lucy is an amazing and beautiful spacecraft.

And it all works well together, visiting so many different Trojan asteroids. One thing that I think is interesting is that the first two Trojan asteroids we fly past, Yerba Aedes with its small satellite Keta, and then Polymele, we fly past them just about one month apart. And so we're really setting that up and almost, you know, thinking about, you know, playing billiards and shooting pool and flying right down that line. I think the orbital mechanics of that is just beautiful because it's kind of so pure. It is. It is. I mean, it's a cosmic dance. I called it a cosmic ballet. And thank you for the correction, Mike. You know, I look at Cassini, which tooled in and around the Saturnian system for so long, which also had just those chemical main engines to make it a huge success.

Hopefully Lucy will see the same kind of success. Well, we certainly plan that to be true, right? And we're, you know, we're doing something that, building on what Cassini did, because really the Earth is doing all the work, right? When it comes to setting up our encounters, right? The main engine is doing some tweaks and, you know, the thrusters, a little bit smaller tweaks, but the Earth is doing all the heavy lifting.

And to me, that's a very elegant solution. Fortunately, Earth has some momentum to spare. Yeah, that's right. We'll steal just a little bit of it. But that posed some interesting engineering challenges from the standpoint of, you know, we had three Earth gravity assists, but depending on when we launch in the launch period, our first Earth gravity assist could be as low as 300 kilometers. That's low Earth orbit type of distances.

So even though the spacecraft had to be designed for deep space operations, we had to take into account what typical low Earth orbit spacecraft orbit spacecraft do by passing that low with aerotorque, aerothermal heating, electrostatic discharge. So we've had to deal with those kinds of complications, which is very unusual for a deep space mission. Right, and with these really large solar arrays. Yeah, with large solar arrays. It blows a whole horse at that. I mean, we had to go, I had to take a sample of the arrays to a special facility at NASA Glenn

and expose it to a plasma arc to help simulate the electromagnetic discharge and make sure they won't short themselves out going through the atmosphere this low, which, again, is not normally what you would think of for a deep space mission. And we also go as close to the sun as 0.83 AU. So we're within Earth's orbit for part of the mission. So we had to account for the thermal extremes there as well as past Jupiter. That beautiful orbital solution has posed some technical challenges to the engineering team that we definitely met and overcame, but definitely required some special thinking. It didn't occur to me until now, but with those

giant arrays, I suppose as you continue to adjust your trajectory, you've got to take into account that you're going to be a bit of a solar sail as well. The solar radiation pressure that is going to be coming from these arrays is something we definitely had to take into account. We've known that from the beginning. And yes, that is something we certainly had to factor in because they are a big solar sail out there, which you guys always talk about. Hal, a lot of us, I'm one of them, would have been thrilled even if you went all this way and did this amazing trajectory and didn't do any

science, but of course you're going to. Can you talk a little bit about what you hope to discover and maybe about these instruments that you hope to make those discoveries with? They have this illustrious and very reliable history, fortunately. Yeah, indeed they do. So we have three main science instruments. All our instruments are L apostrophe. I'm a little bit of a Francophile. Right. So we have the LORI instrument, which is a clone of the LORI instrument that's on New Horizons. Narrow field, high resolution, basically panchromatic telescope. That's really a beautiful design. There's no focus mechanism, right? And so it's designed so that the thermal expansion will keep it in focus throughout the temperature range that will be used to measure the surface properties. We're going to measure the temperature of the surfaces we go by and how the temperature warms up or cools off across the terminator.

That will tell us how fluffy the surface is, for example. We have an instrument called LaRalph, which is based, again, on the New Horizons Ralph, which is really two instruments in one. It's a color camera and an imaging near-infrared spectrograph. So we're going to get three-dimensional data cubes out of it of position and spectrum. of position and spectrum. We're hoping that that's going to tell us a lot about the chemical makeup of the surface of these bodies. In addition, we're going to be able to measure the Doppler shift as we go by, and so get the measurement of the mass.

Remind me, Kathy, what the delta V is going to be. So the delta V that we're measuring this Doppler shift of is about six millimeters per second on top of our base velocity that's between six and nine kilometers per second. So we really have very precise ability to measure the Doppler shift to determine the mass of the Trojan asteroids as we fly by. And I'll just remind everybody that's using the spacecraft's radio and the clock that's built into it to make these ultra fine measurements of just the shift in the signal that's coming back to Earth, well, going to the spacecraft and coming back to Earth. Fascinating.

Which means we can't use the thrusters during that time. So we've had to plan that into our concept of operations because any small little thruster firing would make it hard to pull out that measurement. So, you know, that's a very, part of that carefully choreographed con ops there is we've got to take that into account. That's certainly true. Yeah. It's very much like a dance. Everything has to work together. And we also are using our terminal tracking cameras for science. We have two terminal tracking cameras on our instrument pointing platform. And they're there so that we can make sure that we're pointing at the Trojan asteroid as we fly by. They'll be able to take

images of the Trojan asteroid and on board do state estimation and point the instrument pointing platform at the Trojan asteroid, effectively collapsing the uncertainty ellipse between the relative position of the spacecraft and the Trojan asteroid. That's why we have the terminal tracking cameras, and these are very wide field cameras, and we realized that these images would also be useful to determine the shape of our targets. As you heard before, we are measuring the mass, and then you combine the mass with the volume, and that's how we'll get density, which is really a very diagnostic feature of the origin and evolution of small bodies in our solar system. Hal, you used the word pristine, which takes us back to one of the justifications for this mission, right? Because we are, we expect at least some of

these objects probably will be able to take us back to the earliest era of the solar system. Yeah, you know, if you look at what NASA and the other space agencies have been doing, they've been spending a lot of time studying these small bodies, asteroids and comets and things like that. In a real sense, these populations were affected and sculpted during the planet formation process and relatively have been unperturbed since then, right? So the best way, I think, and I've pretty much dedicated my career to do this, to understand the history of the solar system is to study these small body populations. Did you have to take planetary protection into consideration as so many other missions have to. Mike?

Yeah, so all of the missions we have to work with headquarters to make sure that we meet our requirements and the Coast Guard agreements for planetary protection. Even though these are the Jupiter Trojans, because of the ground points are 60 degrees in front and behind Jupiter in its orbit and space is a big place, the closest we ever get to Jupiter and Europa, which, of course, is a big concern, is actually on launch day. And then because we are going on this basically six-year heliocentric orbit around the sun that gets us to the L4 and L5 swarm, space is a big place. So we did the analysis, and we don't have any concerns for Europa or Mars.

Turns out at the first DGA, we're closer. Oh. So the statement is not quite right. I don't know if you want to re-say that. That's okay. When we do our first Earth gravity assist, which will be next fall, we're actually just a little bit closer. We're a little bit closer.

next fall. We're actually a little bit closer. We're a little bit closer to Jupiter. But it is true that the spacecraft is closest to Jupiter when it's sitting right near the Earth. Just fascinating. And give us a good idea of just how huge the orbit

of Jupiter is. That's right. Let me restate that real quick, Matt. You can. I don't mind. I mean, that was kind of entertaining, actually, what we just went through. It's kind of splitting hairs. I would keep it.

I would say you don't need to worry about it, if it's okay with you. I'm fine. But I got to look. Either way, I do have paperwork from headquarters that says we don't have to worry about planetary protection. We had to get that signed. Maybe this is another one for you, Mike. But everybody, jump in if you like. Give us an idea of what's ahead.

I mean, 12-year mission, primary mission at least. With any luck, we're going to see a beautiful launch on Saturday, October 16th. What are the next big milestones as we look out across this mission profile? After we launch, of course, we're going to have several weeks of checkouts, making sure that everything is working properly in the spacecraft, deploying the instrument pointing platform because it's in a locked position right now, and doing some calibration checkouts on the instruments in the spacecraft. Like I said, about a year later, we're going to do our first Earth Gravity Assist basically next fall, and that, again, stealing a little bit of energy from the Earth.

We'll go on to a larger orbit two years after that is when we'll do our next Earth Gravity Assist, and that will give us enough energy to get out to the L4 swarm. Before we get there, though, in 2025 is when we do our flyby of the Donald Johansson main-built asteroid, and that is going to get its own science of its end of itself. We will be using that to help test some of our sequences and basically use that as a rehearsal for the Trojan asteroids. And then from 2027 through 28 is when we're in the L4 swarm. And that's where we encounter Polymerely, Euripides, Lucas and Oris.

And then we come back around for our third Earth Gravity Assist that then tilts our orbit a little bit, that gets us out to the L5 swarm to do that Patroklos-Menezes binary in 2033. Hope your calendar is clear all the way out. Well, I mean, that does bring up what we've heard from so many other people on other missions. Exploring the solar system requires the greatest of patience, doesn't it? There's no doubt. One interesting fact I think about, Lucy, is we're going to be traveling for 12 years. That's the length of the mission. But all our important science is going

to be collected within a total period of 24 hours. Wow. Right. That tells you how fast these encounters are. So each one is basically a two-hour stretch. I mean, obviously we're taking data on approach and leaving, but all the important science really is in that two-hour approach or egress, depending on which encounter it is. So there's going to be a lot of sitting around and the spacecraft is going to be waiting. We're not going to be waiting. We're going to be busy planning the next one, but it is true that

the spacecraft will be just waiting for a long period of time. That's right. We have a lot of science planning to do to make sure that we really have the best and robust science return that we'll be able to get from the Trojan encounters. As Hal says, they're very fast. And so time is a critical commodity. And we're going to have to spend a lot of time planning that to really optimize what we get back scientifically. It's interesting because I've been thinking a lot about your question, you know, what's next? And it almost seems to me that this mission has been basically a trilogy. So first we had volume one, which was the proposal, and that had one cast of characters. Volume two, we're coming to the end. This is nearing the conclusion of our volume two, where we built this great team and built a spacecraft and developed it.

And then we have the closing book in the trilogy is about to start with our operations phase. And we'll transition and some of the team will roll off to other projects. And we'll be in our with our operations team for the next 12 years so it's it's really like a series of three volumes with different characters after the 12 years though the spacecraft should still be in good health it should still love for palatine board so oh yeah it could be like the foundation series and go on and on and on are you watching i. Are you watching? I'm pretty impressed with the episodes I've seen so far.

I haven't had time. After launching Checkout, it's high on the list. It's a good update to classic science fiction. Hal, I'm thinking back to you talking about being in junior high during the Pioneer missions,

and now I'm thinking of a 12 year old who may be out there right now, who by the time this mission is ready to end or move on to whatever it moves on to in 12 years, that 12 year old might be a grad student or even a post grad working with Lucy Data. There is no doubt, right, that this is a multi-generational mission, right? We have built into our plan succession plans, right? So as people age out and retire, bringing in new people in, and that's expected to continue to the very end. So people that are in college now or even in high school now should think about coming and joining us sometime. There's plenty of opportunity.

Yeah, I gave a talk at my son's school. My son's in elementary school. And halfway through my talk on Lucy, it dawned on me that these elementary school kids I was talking to were going to be in college when we did the PM binary flyby. I mean, it really is, again, these long, long duration missions, really, it's a multi-generational endeavor. Yeah, and I think about it from our student collaboration perspective. When we were selected, we didn't have a student collaboration. And Dr. Thomas Zurbuchen suggested that we think about it. And we really thought, how can we reach the most people? We were fortunate. We brought in folks from Arizona State University to help lead that effort,

and we've reached, I believe it's over 6,000 students over the course of our offerings. We have virtual academies. This can lead to internships. We have instrument incubators. We have a Lucy Ambassadors program. These students who are in college now can easily be working on the mission in the future in that time frame in their career. And so I think that's a really exciting thing to look forward to. And Kathy, that's exactly what I was going to ask you about next, because I saw some activities on the website. I think you probably are reaching a lot more than 6,000 young people because, I mean, one project was encouraging kids to make time capsules that, you know, they can add things to over the years and then open them up in 12 years. There's some really fun stuff to get kids involved that everybody can find on the Lucy website. That's right.

That's right. That's right. The time capsule idea, I think, is just outstanding because, like Mike said, this time scale is different than most people's regular experiences. And so being able to capture what we're doing in October of 2021 and then look at it again in 2033 is going to be remarkable. And in fact, I put together a collection of items for my own time capsule. And it'll be interesting to see what I think of them when I get to 2033. I'll be like, why did I have this in there? What was that important for? That's part of the fun of a time capsule. That's right.

Listen, you three, you've been very generous with your time in what I suspect might be a kind of busy period. Let me just finish with this. Where will each of you be when that, I think it's an Atlas 5, lifts off with Lucy in just a few days? Hal? I will actually be part of the polling for launch. So I will be in the control center called ASOC at ULA during the launch. And I'll be in the test control center

where we'll be monitoring the telemetry from the spacecraft. So we have a lot of family and friends coming down, but we actually won't get to see the launch ourselves. You'll be working. You'll be working, watching a computer monitor, making sure that everything's healthy with the Lucy spacecraft

all the way through the solar. I'm going to run outside, watch the launch, and then run back inside. There's no way anybody's going to stop me from seeing the launch. Yeah, you and everyone. That's right.

I'm going to try and be in two places at once, basically. I'm Hal's backup for the polling. So in the beginning of the night, I'll be at a place called Hangar AE. It's one of our control areas. And then I will drive across the causeway to a building over at Kennedy Space Flight Center and give a briefing to some people about the mission and watch the launch from there with them. And then I will scoot quickly back over to Hangar AE to see the telemetry come back down. So I'm going to be very excited to kind of be

everywhere all at once. I only wish that I could be there at the Cape with the three of you. It is going to be so exciting. Just know that a lot of us out here at the Planetary Society and many other listeners to this show are also thrilled. And I know that I speak for them when I wish you the greatest of success and the greatest of science ahead from the Lucy mission. And thank you for this time today, all three of you. Go Lucy. Go Lucy. Peace and love. Go Lucy.

Peace and love. Go Lucy. Peace and love. Go Lucy. Peace and love. Lucy Principal Investigator Hal Levison, Deputy Principal Investigator Kathy Olkin, and Deputy Project Systems Engineer Mike Sekirak of the Lucy Mission. Time for What's Up on Planetary Radio. Here is the Chief Scientist of the Planetary Society.

Wait a minute, I got something to read to you. I almost forgot. It's from our longtime listener, Elijah Marshall in Australia. I'm loving listening to Bruce. Is he as much fun in the office as he is on the show? Well, Elijah, the answer is I don't know because I haven't been to the office in a year and a half, much less been there with Bruce. Are you fun in the office still? No. There you have it, Elijah. Straight from the mouth. Yeah, right. What's up? No, I'm home almost all the time and I'm big fun, big fun at home.

Always, always. Let's just jump into the night sky. So we've got, it's just lovely in the evening sky You've got soon after sunset over in the east Venus, really, really bright And it is getting pretty darn high for Venus So easy to see You turn over to the other part of the sky And the other really bright object is Jupiter With Saturn to its right

And over the coming weeks and couple months, they'll all be getting closer together. It'll be a fun festive time. But for now, they're still lovely in different parts of the sky. And I've got Mercury. Mercury making an appearance in the pre-dawn east. You're going to need a nice view of the eastern horizon looking fairly low down, but it's coming up and we'll be there for two, three, four weeks. On to this week in space history. It was 1997, Cassini-Huygens was launched on its way to the Saturnian system. 2003, Shenzhou 5 was launched and Yang Lui became the first Chinese astronaut.

And in 2018, BepiColombo was launched, and it's been flying past Venus and making its way gradually to Mercury. And just made, what, a couple of weeks ago now, that first pass of Mercury, and got some really cool images, some of which we have had at planetary.org. They're fun. And we look forward to more in the coming years. For now, though, we move on to... I don't know what to make of that. I don't either. You've been hearing about the Lucy mission.

In fact, on this show. Exactly. I know these things. You've been hearing about the Lucy mission. In fact, on this show. Exactly. I know these things. And although I haven't heard the episode yet, but the custom of naming the Trojan asteroids of Jupiter after Trojan War figures from the Iliad, Johann Pellice of Vienna, who was the first to accurately calculate their orbits,

and I don't know if you discussed that in the leading orbit, leading Jupiter, named after Greek heroes, trailing orbit named after heroes of Troy, but just to confuse matters, there's a spy in each camp with one Greek in the Trojan, one Trojan in the Greek camp. I don't know if there's a horse involved, but they were named early on before the convention took place. No, that did not come up. Thank you for those tidbits, those sub-RSFs. We're getting into the details. We've been on the air for a long time. All right, we moved on to the trivia question. I asked you, what moon of a, this was such a kludgy question, I'll be curious how we did. What moon of a planet has an orbital sidereal period closest to 24 hours? So it takes about 24 hours to go around its parent planet. How'd we do, Matt? planet. How'd we do, Matt? We got such a variety of answers on this one. There were some ones that came very close, some not so close. But the general opinion was, the consensus was, well, it all consolidated in one. And I will let Dave Fairchild, the poet laureate, provide it to us. Methone is an egg-shaped moon, a ball of fluff, I guess. It lives in Saturn's

E-ring and is also craterless. At barely three kilometers, Cassini gave it worth by showing that its orbit time is just the same as Earth. Almost, anyway. According to Norman Cassoon in the UK, Norman Kassoon in the UK and a lot of other people, its period is, or its rotational period is exactly, or very nearly 1.009573975 Earth days, sidereal measurement. In fact, I think you specified that actually. I did. And it's actually, I mixed and matched. That's why I say it's Kluge. It's the orbital period, how long it takes to go around the planet, which isn't necessarily the same as the rotational period, which is what our 24 hours is approximately. Can I tell Norm, Norman Kassoon, that he's our winner? Yes. Another one that was the end of a long dry spell. His last win was in January of 2017. So those of you out there who are still wandering in the wilderness, keep the faith.

We're going to send Norman, by the way, a Planetary Society kick asteroid, rubber asteroid. How's that? Congrats, Norman. Congrats. And here are some more contributions from listeners. Laura Weller, also in the UK, she says, So Mathon is a moonlet? I didn't know a moonlet was a thing until this contest. Cute. My new favorite thing in space.

I've always enjoyed a good moonlet. Chris Mills in Virginia, please send me a rubber moon instead. Sorry, Chris, we only have paper moons. Matthew Eason in Virginia, here's a fun fact. He says Neptune has both the moon with the shortest period, it's Niyad, at 0.294 days, and the longest period, Neso, days. And the longest period, Neso, or Neso, 9,374 days for that little pup to get around Neptune. My gosh. I almost used those as part of the show. Yeah, I love that.

Here's a fairly long one, but it's interesting from Kent Murley about the nature of this moon. He's in Washington. Methone rides in a dust ring, a close-in partial arc separate from the main icy rings. Her orbit varies along and around this arc every 450 days because of a resonance with the dreaded Mimas. Do you hear the Imperial March playing in the background? I really do hear it in the background. So will we still catalog it as a moon a century from now? Or an electrostatic dust storm rafting a gravitational river? I think it has a moonlit core in there. I can't handle Terran dust bunnies.

I advise not landing there until we know how to handle lunar and Aryan or Martian dust. Imagine trying to climb out of a bagless bean bag in zero G. Wow. I'm going to have to put that aside to think about later. That's wow. I loved it. Yeah. I didn't know how to have a big thing on it.

You know, like, like there is for a Europa, a temp no landings here because you'll just disappear. Yeah. Methone is a weird place. It's weird looking. I encourage people to pull up a picture from Cassini. It's interesting with its sort of ellipsoidal shape and lack of craters probably caused by being all fluffy. Here is a poem to close out with from Jean Lewin, also in Washington. Three sisters of the Alcyonides are dynamic in their ways. Under the effects of Gaia's sun, their orbits tend to stray,

but forging on like all good eggs, the phone never cowers, orbiting round Saturn's girth in about 24 hours. It looks kind of like an egg. I get it. It really does. All right, we're ready to go on to another contest with another special deadline. All right, we're coming back to Lucy. So most of the asteroids to be visited by the Lucy mission are Trojan asteroids named after characters in Homer's Iliad. But what two objects to be visited by Lucy are named after real people? Go to planetary.org slash radio contest. Wow. This might be a tough one, but you've got two weeks this time, not three like last week. In fact, we've got the same deadline we gave you last week of October 27th. That's Wednesday, October 27th at 8 a.m. Pacific time. And we'll have

a cool little maybe it'll be warm, I don't know, a little Planetary Society rubber asteroid waiting for the winner of this contest. Alright, everybody, go out there, look out in the night sky and somewhat unfortunately think about macrame. Thank you and

good night. I just don't understand. Why would macrame be unfortunate? All right, we love the macrame. Good. That's Bruce Betts. He's the chief scientist of the Planetary Society who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society

in Pasadena, California, and is made possible by its members who, like Lucy, are diamonds in the sky. You can shine with them at planetary.org slash join. Mark Hilverda and Jason Davis are our associate producers. Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. Ad Astra.