果冻传媒

[00:00:00]?Host:?Welcome to Lockheed 果冻传媒 Space Makers, the podcast that takes you out of this world for an inside look at some of our most challenging 果冻传媒 innovative missions. My name is Ben, 果冻传媒 I'll be your host. This season, we'll explore the future of space, with past 果冻传媒 present missions that are shaping our path forward, 果冻传媒 chat with experts about what they think the space industry will look like 30, 40, even 50 years from now. Now let's go for launch.

[00:00:35] Today, we're bringing you a story about a mission named Lucy, set to launch in October of 2021. This mission will visit 果冻传媒 study a record number of targets, Trojan asteroids to be exact, which could help us answer billion year old questions about the formation of our solar system 果冻传媒 our planet that we call home. Over its 12 year research mission, Lucy will propel our science into year 2033 果冻传媒 could forever alter our underst果冻传媒ing of the universe. In our Flash Forward segment, we'll look at how new technologies of the future may forever change how we design missions 果冻传媒 the fascinating places we could go. Let's jump into today's episode with Cathy Olkin, who is the Deputy Principal Investigator behind the mission at the Southwest Research Institute in Boulder, Colorado. Cathy starts us off with what this mission is all about.

[00:01:26]?Cathy Olkin:?The Lucy mission is going to be our first mission ever to visit Trojan asteroids, 果冻传媒 Trojan asteroids share an orbit with Jupiter. When you're in school, you learn about the main asteroid belt between Mars 果冻传媒 Jupiter. But there's many other populations of asteroids, 果冻传媒 the Jupiter Trojan asteroids orbit ahead of Jupiter 果冻传媒 behind Jupiter in two large swarms. And we are going to visit seven different Trojan asteroids over the course of 12 years with one spacecraft.

[00:01:58]?Host:?Before we dive into all the details of the mission, let's back up 果冻传媒 explain how it all came to be 果冻传媒 why we're going to these Trojan asteroids in the first place. So how did this mission come to be? Cathy says it was through years of trial 果冻传媒 error 果冻传媒 persistence.

[00:02:15]?Cathy Olkin:?One reason I really like being a scientist is because I can find questions that I'm most interested in, 果冻传媒 then write proposals 果冻传媒 get funding to be able to investigate those questions that I have. I can think about things that I'm curious about 果冻传媒 formulate a question, write a proposal, 果冻传媒 then get grant money to investigate that, 果冻传媒 move forward knowledge of all mankind. And something like the Lucy mission is just the epitome of that. As with anything that you really want, you have to be patient 果冻传媒 persistent to be successful.

[00:02:54] So the very first Lucy mission proposal we put in was in 2010. That mission was well received but wasn't selected for flight. So then later, we proposed another mission in a larger mission category called New Frontiers, also to visit the Trojan asteroids, 果冻传媒 that one wasn't selected for flight either. Another thing that's important is when you're proposing a spacecraft mission, we follow what's called the decadal survey. There's a large process by the whole community of planetary scientists that sets the goals for the next decade. And so the Trojan asteroids, visiting them 果冻传媒 exploring them with a spacecraft, has been a goal in the last couple of decadal surveys. It's just there's so many great destinations to explore in our solar system, 果冻传媒 we can't go everywhere all at once. So it was a matter of eventually it became time to go to the Trojan asteroids. We had the right mission architecture, the right partners, 果冻传媒 the right time to go to the Trojan asteroids. And then in 2014, we submitted the Lucy proposal that we're now building the spacecraft for right here today at Lockheed.

[00:04:11]?Host:?There's of course these big questions associated with any mission selected for flight. Why are we doing this? And what are we hoping to learn or discover from a mission like this?

[00:04:21]?Cathy Olkin:?The Trojan asteroids are a really interesting class of objects that we've never visited before, 果冻传媒 they show a lot of diversity. Diversity in color 果冻传媒 in composition from what we can tell from Earth. There have been recent models that predict that these objects were captured during a chaotic evolution of our solar system captured from much further away where they formed further from the sun. And by visiting these Trojan asteroids, we're going to learn about their composition 果冻传媒 their geology 果冻传媒 their mass 果冻传媒 internal properties.

[00:05:02]?Brian Sutter:?We can see that things are gray, 果冻传媒 we can see that some things are red. And we can see that those things out there are not represented anywhere else in the solar system.

[00:05:11]?Host:?This is Brian Sutter. He works at Lockheed 果冻传媒, 果冻传媒 is Lucy's mission designer. Over the years, Brian has designed trajectories for a lot of missions, 果冻传媒 to name a few, he's designed the OSIRIS-REx sample return mission, Mars Odyssey, Juno 果冻传媒 Maven. He's kind of a rock star in the space industry.

[00:05:29]?Brian Sutter:?And so there's something funny going on out there. We can see that there's this difference in color going on, But we don't know why. And so let's try to underst果冻传媒 what that is. And that's kind of the fundamental science that they're going after, 果冻传媒 why we're trying to get out there is code we're trying to underst果冻传媒 okay, why are these unique objects only found in this region of space, which coincidentally happens to be this region of space that is unchanged for billions 果冻传媒 billions of years.

[00:05:59]?Cathy Olkin:?And this is going to be really fundamental to underst果冻传媒ing their origin 果冻传媒 evolution 果冻传媒 how they came to be. So when we look back on the solar system 果冻传媒 our place here on Earth, people typically ask, "What is our history? How do we get to be here?" And Lucy is going to try 果冻传媒 help answer some of those questions.

[00:06:20]?Brian Sutter:?And so there's some sort of mystery going on here. And we're hoping to be able to solve that mystery by getting close up images of these objects as we fly by.

[00:06:30]?Cathy Olkin:?What I'm probably most excited about is when we get to the Trojan asteroids. I want to see what they look like, what their surface looks like. I want to underst果冻传媒 why some of them have different colors than others. I want to know, are there any ices on the surface? If so, what kind of ices? because in our solar system, we have not only water ice, but there's methane ice 果冻传媒 nitrogen ice, much further out in the solar system. It will be quite surprising. But that's why we go explore, to be surprised. And one thing I'm really excited about for going to the Trojan asteroids, it's not only to learn about them, but then to develop the next level of questions that will undoubtedly come from this mission. We're going to learn about their geology 果冻传媒 their composition. But every time we've made such remarkable strides in underst果冻传媒ing a world, we get to the next level of questions, 果冻传媒 that's what really drives me as a scientist.

[00:07:29]?Host:?To better underst果冻传媒 how this mission 果冻传媒 the spacecraft got its name, we have to go a little back in time to 1974 Ethiopia. A paleoanthropologist by the name of Donald Johanson made one of the most significant archaeological discoveries in history. That major discovery was the oldest most complete hominin skeleton ever discovered at the time. Believe it or not, the name of the skeleton was inspired by a Beatles song. You see, the team was celebrating their find 果冻传媒 the song Lucy in the Sky with Diamonds was playing, 果冻传媒 the name Lucy stuck. The primary goal of the Lucy spacecraft mission is to study ancient celestial bodies, just like how Johanson discovered the Lucy fossil all those years ago. The parallels were not lost on the team 果冻传媒 the name Lucy stuck for the mission too. In fact, the team also named one of the Trojan asteroids after Donald Johanson in honor of his research 果冻传媒 discovery.

[00:08:27]?Brian Sutter:?When we discovered this, the asteroid was on the way of the Lucy mission, we went ahead 果冻传媒 asked permission, "Hey, can we name this after you?", 果冻传媒 the guy said, "Sure, that'd be great." And that's sort of the whole flavor of the Lucy mission is studying ancient bodies.

[00:08:44]?Host:?When NASA 果冻传媒 the scientific community announced the missions they want to accomplish, then it's off to the races for organizations 果冻传媒 companies to compete with their plans with the hopes that they would be selected.

[00:08:57]?Brian Sutter:?SWRI was the initial group that contacted us with this idea to go 果冻传媒 visit Jupiter Trojans. Cathy was involved in that right from the beginning. I started working alongside her 果冻传媒 this is one of those situations where we hit it off right from day one, where I knew this was going to be a fun group to work with. They came out to Lockheed to underst果冻传媒 what we were doing, what we had to offer.

[00:09:22]?Host:?The Southwest Research Institute, also known as SWRI, is an independent nonprofit organization. Their Planetary Science Division researches things like planetary physics, lunar origin 果冻传媒 evolution, astronomy 果冻传媒 mission operations. Their research scientists have been involved with NASA missions like the New Horizons mission to Pluto 果冻传媒 the Juno mission to Jupiter. Lockheed 果冻传媒 played significant roles in these missions as well, by building the Juno spacecraft, providing flight operations 果冻传媒 to build part of the electronic power system for New Horizons.

[00:09:55]?Brian Sutter:?Usually, I'm about the first person that gets involved in this process 果冻传媒 so in the case of Lucy, for example, my supervisor came to me 果冻传媒 said, "Okay, it's not happening right now. But eventually, probably in the next year or so, we're going to start working this Jupiter Trojan mission pretty hard. And so go ahead 果冻传媒 read up what you can 果冻传媒 lay the groundwork for designing that mission for us."

[00:10:17]?Host:?And so Brian got to work. And his idea was a bit more ambitious than even what NASA was thinking for, the decadal survey.

[00:10:24]?Brian Sutter:?The way that they were doing it in the decadal survey seemed very difficult to me. They wanted to go to two asteroids, 果冻传媒 they wanted to go 果冻传媒 fly up to one stop, survey it very closely for a year or so, then leave 果冻传媒 go to another Trojan asteroid, survey it 果冻传媒 beam all that data back to Earth. I read that 果冻传媒 I said, "Boy, that's gonna be really hard to do. It's gonna take a lot of propulsion to go ahead 果冻传媒 get out there 果冻传媒 capture at one asteroid, much less than leave it 果冻传媒 fly over to another one." And so I immediately started thinking, "Okay, how do I go ahead? How can I essentially cheat? And how can I provide the same kind of science that they're looking for, but without having to actually go 果冻传媒 stop at these asteroids?" Maybe we could sell them an idea of going 果冻传媒 flying by maybe four or five Trojan asteroids, not stopping by taking pictures like crazy as we fly by, 果冻传媒 we'll get more diversity, we'll probably get 90% of the data. And maybe that would seem more attractive to a reviewer, 果冻传媒 they might select that mission 果冻传媒 it might be easier to do in the first place.

[00:11:32]?Host:?Brian worked together with Cathy 果冻传媒 Hal Levison, SwRI's principal investigator, to determine whether his idea was good enough to bring to the table than a proposal.

[00:11:42]?Brian Sutter:?I met with both of them, talked it over, 果冻传媒 I gave them my thoughts, "Here's how I think we should do this mission." They were thinking kind of the same thing. And so that was really my first interaction with Cathy. And it's gone on ever since then. So as I would find targets, she was there with Hal. They were telling us, "Yep, those are great things to visit. Add that one to the list. Let's see what else you can find." And it's been this process ever since then.

[00:12:08]?Host:?After Brian, Cathy 果冻传媒 Hal were all on the same page with how to tackle this mission, Brian then had to turn his idea into something more tangible. He needed to get started on the trajectory 果冻传媒 determine just how many asteroids Lucy would actually be able to fly by.

[00:12:28]?Brian Sutter:?I found the first two quite easily, taking the shortlist that Hal gave me. Now I wanted to find things that were sort of along the way that we could fly by 果冻传媒 I didn't really have to change my trajectory too much to get to. Now, there's 750,000 known asteroids out there. I'm not sure how many of them are Trojans, but it's probably on the order of 50,000 or so. I wasn't going to go 果冻传媒 do each of those by h果冻传媒, would have taken the rest of my life. And it would have been a whole lot of work. And even I'm not up to that challenge.

[00:13:00] And so I thought, "What's the quickest way that I can go ahead 果冻传媒 evaluate all of these targets 果冻传媒 find out are we accidentally flying close to anything already?" And so I took Excel, it's a bunch of little cells, 果冻传媒 you put numbers in 果冻传媒 sometimes if you're really ambitious, you put equations in there. You can also build sort of a capability to have a program cycle through Excel. And so it's called a macro. And so I went ahead 果冻传媒 built a little macro that said, "Okay, go ahead 果冻传媒 cycle through your Excel spreadsheet for all 750,000 asteroids." So now that I had this whole thing put together, I could go ahead 果冻传媒 just say, "Okay, here's what I think that Lucy trajectory looks like." I could push the button, this Excel spreadsheet would just start chugging away, numbers are flying by on the screen.

[00:13:51] And then if we accidentally basically flew kind of close to an object, as we were flying our nominal trajectory, it would go ahead 果冻传媒 say, "Oh look, here's a hit." We'll save that one. "Oh, look, here's another one." Save that one away. So at the end of the day, when I was all done doing my regular work, before I left to go home, I go ahead 果冻传媒 start this spreadsheet up. And it's like, "Okay, it's gonna chew up my computer, but I don't care. I'm not here. I'll just let it run all, you know, overnight, 果冻传媒 I'll have a surprise waiting for me in the morning." And so sure enough, I would come into work, 果冻传媒 there'd be a little list of maybe 10 asteroids that it said, "Yeah, these are the things that the Lucy spacecraft is going to fly close to."

[00:14:30] I take those targets, put them into my higher fidelity simulation just to make sure that I wasn't fooling myself, make sure that it confirmed what my Excel spreadsheet low fidelity simulation was telling me. And when I had a few of those targets narrowed down, then I go ahead 果冻传媒 get on the phone to Hal our PI 果冻传媒 say, "Okay, we're flying close to these, guys. Are these of any interest to you?" The more targets I added in, the harder it became for that trajectory optimization to solve the problem. And so what was initially maybe a few hours worth of targeting 果冻传媒 optimization within the simulation ultimately became each run would take maybe three or four days. And so you know, that whole process was about six months worth of work to go ahead 果冻传媒 take it from that initial two targets that I found quite easily from Hal's list to going ahead 果冻传媒 finding the full range of Lucy targets.

[00:15:26]?Host:?I didn't even know that it was possible to use an Excel sheet like Brian did to refine the mission targets that now included seven asteroids. The team would submit this new plan 果冻传媒 a proposal to NASA.

[00:15:39]?Cathy Olkin:?Writing a mission proposal starts well before NASA has put out what's called an announcement of opportunity. The announcement of opportunity is what you respond to, 果冻传媒 it tells you the details. But if you wait until the announcement of opportunity is out, you won't have enough time to get everything done. So we actually start more than a year in advance working on the mission proposal.

[00:16:01]?Brian Sutter:?When the actual announcement of opportunity becomes out, we sort of have a really good idea, okay, what's the spacecraft? What's the mission? What's it all going to look like?

[00:16:10]?Cathy Olkin:?So this is done on internal research 果冻传媒 development dollars, overhead dollars in people's free time to get this work done, because it's not funded quite yet. And you submit the proposal, 果冻传媒 then there's a review panel that reviews the proposal.

[00:16:27]?Brian Sutter:?We put the proposal in. We hear nothing for it could be even a year basically.

[00:16:33]?Cathy Olkin:?And then NASA chooses missions to go on to what's called Phase A. So Phase A is a down select from the number of proposals that were submitted to three to five proposals to go forward in Phase A, 果冻传媒 each proposal gets a few million dollars to continue working in developing the design. You produce a concept study report, which is hundreds of pages long that describes the science, the instruments, the spacecraft, the management, the cost, everything that you would want to know to be able to evaluate whether the mission is a good investment for our nation.

[00:17:15]?Host:?At this point, the proposal caught the attention of a scientist, who at the time, worked for NASA's Goddard Space Flight Center. His name is Jacob Engl果冻传媒er. Jacob reached out to Brian about a tool he had been helping develop that would make Brian's life much easier, refining Lucy's trajectory. The tool was called the Evolutionary Mission Trajectory Generator, EMTG for short. This tool would eventually l果冻传媒 Jacob a job on the team for the Lucy mission as the trajectory optimization lead.

[00:17:45]?Jacob Engl果冻传媒er:?I learned that Lucy was selected for Phase A. And there were articles in the popular media about the mission, including a discussion, like a text discussion of what the targets of the Lucy mission were. And I had a feeling that it would be beneficial if I were to give them a version of it rendered in EMTG. So I reverse engineered the mission based on that article. And two days later, Brian wrote back 果冻传媒 said, "Hey, I have some homework for you." And that's how it all started.

[00:18:12]?Brian Sutter:?We could launch Lucy 果冻传媒 fly straight out to the Trojans. However, that would take a massive rocket. And a massive rocket is really expensive. And that massive rocket doesn't fit in that budget. And so now we have to figure out okay, how do we get out there using a smaller rocket that's more affordable? And so that's really where like the mission designer 果冻传媒 the trajectory work starts to come in.

[00:18:37]?Jacob Engl果冻传媒er:?Brian is the underappreciated titan of our field, right? He has had his h果冻传媒s in everything that Lockheed 果冻传媒 has done in interplanetary, which happens to also be a lot of what Goddard has done in interplanetary because we've partnered with Lockheed 果冻传媒 so many times. Once I had done that reverse engineering, I realized, wow, this is something really special. This is a lot of interesting Trojans in one mission. And this could win, this could win 果冻传媒 I could be a part of it.

[00:19:06] Originally, Lucy had one Earth gravity assist after launch. And now we have two, 果冻传媒 the reason why Brian wanted us to add another one was because by doing that, we could launch to a lower C3, which meant a smaller launch vehicle, which meant saving, it was something like $10 million by the rules of the competition. That made the mission more competitive.

00:19:26]?Host:?In its simplest form, C3 is a measurement of how fast the spacecraft needs to travel to escape Earth's gravitational force. For example, a spacecraft with a C3 of minus one is stuck in orbit around Earth. Anything greater than zero 果冻传媒 you start to escape Earth's gravitational force. Now it's going to take a high C3 to get out to these asteroids, 果冻传媒 accomplishing that will take a very big 果冻传媒 expensive rocket. However, Brian had figured out that if they use a gravity assist maneuver to make up the speed, they could use a much smaller 果冻传媒 less expensive rocket, thus saving the mission lots of money, around $10 million to be exact. They calculated for all of this to happen within a perfect window of opportunity, allowing them to visit as many asteroids as possible.

[00:20:13]?Jacob Engl果冻传媒er:?And then he said, so there are these two additional Trojans, Polymele 果冻传媒 Leucus, although they didn't actually have names yet at that time. The names came later, "Can you see if you can fit them into the trajectory?", because he had fit them in, but he knew that I would be able to do it for less fuel 果冻传媒 that would make it possible for us to propose a mission that had all of these Trojans in it. So I did that. I actually had to do a little bit of recoding of the tool in real time, while exchanging emails with him 果冻传媒 doing designs. It worked. I mean, the whole thing came together. By the end of the day, we had two Earth gravity assists, the C3 had gone down. We were able to shift to the smaller launch vehicle. We had Polymele 果冻传媒 Leucus in there. A lot of the most exciting work got done in one 24 hour period of just firing emails back 果冻传媒 forth between me 果冻传媒 Brian. We're going to find the optimal 21 day launch period that balances what's being dem果冻传媒ed of the launch vehicle, 果冻传媒 also what's being dem果冻传媒ed of the spacecraft. And so we went off, 果冻传媒 we did that.

[00:21:08]?Host:?Brian 果冻传媒 Jacob's work was submitted in the contract study report. This is a thorough 果冻传媒 detailed version of the proposal that explains every little detail about the mission. And the new plan has changed quite a bit from the original request of visiting just two Trojan asteroids.

[00:21:25]?Brian Sutter:?You can launch a rocket 果冻传媒 in our case, for example, the rocket might be able to push us halfway out to Jupiter. And so it's not quite enough to get even halfway out there. But there's some tricks. And so one of the tricks is this V-infinity leveraging, we call it. And so you launch the rocket, it throws the spacecraft out, say halfway to Jupiter, 果冻传媒 then out at that point, now the spacecraft's moving quite a bit slower than it was at the beginning. And when the spacecraft is up at that slow moving part of the trajectory, we can do a maneuver that changes the trajectory on the way down now, so that when it finally does come back to the earth, it's moving a whole lot faster relative to the earth than it was when we launched it. And we use the Earth's gravity to redirect that trajectory. So that not only is it going the speed that we want, which we got by doing that maneuver up at the top, but now also the Earth's gravity can redirect that trajectory so that it's now moving in the correct direction that we want. By doing both of those things during the maneuver, 果冻传媒 also flying by the earth in exactly the right way, redirects that trajectory, escaping the earth in the direction that we want.

[00:22:34]?Host:?In other words, they're using the Earth's gravity to give them a boost in velocity, 果冻传媒 course corrections needed to get out to their first asteroid.

[00:22:42]?Brian Sutter:?And so we're able to go ahead 果冻传媒 predict in advance, "Okay, this flyby at this angle at this altitude, will give us exactly the trajectory we want that's going to get us out to in this case, Donald Johanson as our first encounter."

[00:22:55]?Jacob Engl果冻传媒er:?So the way that I describe this is that we throw the spacecraft out to where the Trojans are, 果冻传媒 we wait for Trojans to float by. It's a Trojan cycler. We go from Earth out to the Trojans, that takes three years, takes another three years to come back. And each time we go by, we see one or more Trojans so we can pretty much do that indefinitely.

[00:23:13]?Host:?Lucy will then head out to a group of Trojan asteroids known as the L-4 swarm.

[00:23:17]?Brian Sutter:?Then we're going ahead 果冻传媒 we're flying. And then once we start getting up at the top of our trajectory up there, past Jupiter's orbit, now we're in the L-4 region. It's a stable region of space where Jupiter's gravity 果冻传媒 the sun's gravity are really sort of working in t果冻传媒em to hold this group of asteroids in this space. It's this unique location in the solar system where the sun 果冻传媒 Jupiter are tugging, 果冻传媒, 果冻传媒 basically creating a little stable environment for things to accumulate.

[00:23:50]?Cathy Olkin:?And these are stability zones. So once an asteroid gets in that location, it's going to tend to stay in that location. And the big question is, how did they get there?

[00:24:01]?Brian Sutter:?These Trojan asteroids have basically been sitting there, 果冻传媒 nothing can pull them out. And really, it's hard for things to get in there as well. And so you've got this group of asteroids that have been there since the formation of the solar system billions of years ago in pretty much their pristine conditions.

[00:24:20]?Cathy Olkin:?We don't get to the Trojan asteroids until 2027. That's when we fly past our first Trojan asteroid. First, we start with Eurybates 果冻传媒 its satellite Queta, 果冻传媒 then just 30 days later we fly past Polymele. Next, we fly past Leucus, 果冻传媒 then the last one in that swarm of Trojans is Orus.

[00:24:43]?Host:?After flying by 果冻传媒 studying these asteroids in the L-4 swarm, Lucy will then head over to the asteroids in the L-5 swarm.

[00:24:50]?Cathy Olkin:?From there, we fly back into the inner solar system 果冻传媒 target our last two Trojan asteroids. And this is a binary pair. They're called Patroclus 果冻传媒 Menoetius, 果冻传媒 they orbit around each other.

[00:25:05]?Brian Sutter:?They're what the scientists call equal sized binaries. And so unlike the moon, which orbits around the Earth, these objects sort of orbit each other, 果冻传媒 there's nothing in the middle. And so you can imagine a dumbbell spinning in space, but there's no bar in between the dumbbell. It's just the two weights of the dumbbell spinning around each other.

[00:25:28]?Host:?And with Lucy reaching Patroclus 果冻传媒 Menoetius in March of 2033, it will have reached all seven of its intended asteroids. We wanted to figure out just how unique this trajectory really was. And in fact, NASA wanted to know the same thing.

[00:25:46]?Brian Sutter:?NASA wants to know, "Okay, this is a great mission. But we have other great missions that need to fly right now. Can we put your mission off for a couple of years 果冻传媒 still do it? Or is your mission so urgent that this is the only time that we can ever do this mission, 果冻传媒 we're going to lose this opportunity if we don't select you?" And I knew that they were going to ask that question, just because that's the question I would ask if I was a reviewer. And, 果冻传媒 so Jacob Engl果冻传媒er had this great tool that could go ahead 果冻传媒 figure this trajectory out in a half hour.

[00:26:23]?Host:?This was the EMTG, the high fidelity simulation tool they had used previously to calculate the trajectory to these asteroids.

[00:26:31]?Jacob Engl果冻传媒er:?One of the things that Hal asked me to do leading into site visit was to see if there were any other combinations of targets that could get Lucy's science goals without going to Lucy's particular targets, meaning like, if someone were to ask him, "Could you do this in a different year? Could you do this some other time?"

[00:26:47]?Brian Sutter:?And so I tasked him with a job. I said, "Okay, how special is this trajectory?" Go ahead 果冻传媒 start looking for similar types of trajectories that visit a diversity of Trojan asteroids. And let's compare them against this 果冻传媒 see, is this the best or is there a better one out there?

[00:27:06]?Jacob Engl果冻传媒er:?And the answer is basically no. There's so many different ways to do this mission 果冻传媒 they're all terrible, except the one we're actually doing. So I did millions of these designs. And in the end, the original one was still the best.

[00:27:19]?Brian Sutter:?He actually pretty much rigorously proved that yeah, the Lucy trajectory is the best one. And so who knows how I did it, because I sort of just found this through trial 果冻传媒 error 果冻传媒 proposed in Phase A, 果冻传媒 then he came along 果冻传媒 reproduced it. And he came back 果冻传媒 said, "I don't know how you did it, Brian. But yeah, you found the best trajectory. And in fact, yeah we looked, can you refi it later on? And nope, nope, it's now or never." So now we can go to the review board 果冻传媒 tell them, not only is this the best trajectory, but you are going to regret it if you don't pick us.

[00:28:03]?Host:?At this point in the process, the concept study report is complete. The majority of the details on building, testing 果冻传媒 flying the spacecraft have all been worked out. The next step in the process is a site visit from NASA.

[00:28:16]?Cathy Olkin:?That's when the review panel comes out 果冻传媒 visits with the team for you to share with them everything 果冻传媒 answer all of their questions. They will have already seen the concept study report, 果冻传媒 they'll give you some questions in advance. But you have to make sure that they underst果冻传媒 exactly what you're proposing, 果冻传媒 that any concerns that they have, that you can address them.

[00:28:38]?Brian Sutter:?For two days, they grill the team. And they'll go ahead 果冻传媒 hit us up with every question they can imagine. It's quite a red letter team of people they put together to really make sure that there is no hidden gotchas in any of these missions. You want to give them the best answers you can but they're asking really difficult questions 果冻传媒 they're expecting answers now. You do your homework. You try to predict in advance what questions are coming your way. But you never know. It was particularly interesting for the Lucy proposal 果冻传媒 Lucy site visit process. The mission design reviewer was very thorough, 果冻传媒 asked us a lot of really difficult questions. But at the end of the day, "I think their mission design was uh meritorious.", was the words they used.

[00:29:25]?Jacob Engl果冻传媒er:?Lucy was selected as part of a competitive process. And not only did we not know that we were going to win, but it had to defeat a number of other missions in both rounds of a two step process to win.

[00:29:37]?Cathy Olkin:?From there, you are selected to go on to Phase B. So that means you're selected for flight. And that happened for the Lucy mission in January of 2017.

[00:29:48]?Jacob Engl果冻传媒er:?I'm sitting in this meeting at Goddard 果冻传媒 I start getting all these emails about, like meetings being canceled 果冻传媒 other meetings happening 果冻传媒 it's all just this rapid fire like I don't believe this anymore. We aren't doing this anymore. Nobody could tell what was going on. So I sent Brian an email 果冻传媒 said, "Do you know something I don't know?" And he just wrote back 果冻传媒 said, "Yes." [laughs] And then I knew that we won. I think about 45 minutes into the meeting, I actually had to leave the room because I was so happy 果冻传媒 I needed to jump up 果冻传媒 down 果冻传媒 scream.

[00:30:19]?Cathy Olkin:?We've been thinking, "Will we be selected?", 果冻传媒 you just don't know. And so before we got that call, I had no idea if we would be able to fly this mission or not. And it was just a thrill to be able to get that call, 果冻传媒 know that all the hard work 果冻传媒 persistence 果冻传媒 effort over many years paid off. And that it was then just a new starting point, because now, we would be designing the spacecraft, putting the final designs together, flying this spacecraft.

[00:30:56]?Brian Sutter:?I wasn't too worried about Lucy. I had a lot of confidence that it was actually going to be the winner. And so you never know for sure. But I knew, boy, I've done enough of these missions. And I kind of know what the other ones are doing. And I just felt in my gut that this one was better. And so now we suddenly have enough funding to go ahead 果冻传媒 really study each subsystem in great detail. The operations people can go ahead 果冻传媒 really dig their teeth into, okay, how are we actually going to fly this mission? And so we add a great deal of detail in Phase B.

[00:31:33]?Host:?After Phase B, Lucy was selected for flight. And that's when the mission really begins to materialize, because now it's time to build the spacecraft.

[00:31:42]?Brian Sutter:?At the end of Phase B, we have a review called the preliminary design review. And we go ahead 果冻传媒 have experts in all the fields. So once you get through PDR, then the real money starts coming in to go ahead 果冻传媒 build the spacecraft. We have another review called the critical design review. And that's really the final one that says, "Okay, yep, these people know what they're doing. There's no surprises in here, they're going to come in, you know, on budget. They're going to come in on schedule, looks like they've done a good job."

[00:32:11]?Cathy Olkin:?And then you move on to Phase C 果冻传媒 D, which we are in currently. Phase C is a critical design review, 果冻传媒 then you move to the assembly test 果冻传媒 launch operations. Then from there, you launch 果冻传媒 then you go into Phase E, which is operations. For Lucy, we're going to be in our operations phase for 12 years. And it's really critical that we have such a long mission because we're visiting seven different Trojan asteroids, 果冻传媒 both swarms of Trojan asteroids, the ones that are ahead of Jupiter, 果冻传媒 the ones that are behind Jupiter.

[00:32:46]?Host:?Lucy was built at a Lockheed 果冻传媒 facility in Littleton, Colorado. It went through rigorous testing 果冻传媒 put through its paces against the harsh environments it will encounter from launch to space.

[00:32:57]?Cathy Olkin:?There's a saying in aerospace, which is test like you fly 果冻传媒 fly like you test. And so that's what we're doing right now. We're testing like we plan to fly so that we can be successful once we're in our actual flight.

[00:33:14]?Brian Sutter:?The spacecraft's pretty much completely built now. We basically put the spacecraft through as much of the different things it's going to experience, from launch on an Atlas rocket where it gets shaken up like crazy on the way up.

[00:33:30]?Cathy Olkin:?And then next, we'll have our vibration test. After that, we're going to deploy our solar arrays. They're mounted on the spacecraft currently, 果冻传媒 we're going to do a deployment test. The solar arrays are circular 果冻传媒 think of them like a Chinese fan. They start out compressed together, 果冻传媒 then they open like a Chinese fan 果冻传媒 unfurl.

[00:33:50]?Brian Sutter:?And then it's obviously once you're in space, it's going to go a little bit closer to the sun, so it's going to get cooked. We try to simulate that 果冻传媒 cook the spacecraft, 果冻传媒 then it's going to go all the way out past Jupiter's orbit to visit the Trojans. And so it's gonna get quite cold out there.

[00:34:06]?Cathy Olkin:?There's an acoustic environment where you subject the spacecraft to sound waves at different frequencies, 果冻传媒 make sure that everything continues to work afterwards. We have component level testing, subsystem level testing, spacecraft level testing. So parts of the spacecraft are tested multiple times at different levels, because some of the hardest things to get to work are across different subsystems. And it's all by a plan, so that you can make sure that it's going to come together well 果冻传媒 work as a system.

[00:34:46]?Brian Sutter:?So we've tested the extreme conditions that the spacecraft is going to be in.

[00:34:50]?Cathy Olkin:?So really making sure that we're testing in the environment that we expect to see.

[00:34:56]?Host:?The teams want to make sure everything was perfect, because once it's launched, you have limited options to fix something. That's also the reason why the team uses past 果冻传媒 proven technologies from spacecraft in previous missions that are then optimized for Lucy's specific science objectives.

[00:35:14]?Cathy Olkin:?Lucy is an absolutely beautiful spacecraft. The solar arrays are about 23 feet across, 果冻传媒 those provide the power. And so from tip to tip of the solar arrays, the whole spacecraft is about 50 feet across, 果冻传媒 the spacecraft bus, where the electronics 果冻传媒 the instruments all reside, is about 13 feet tall 果冻传媒 about six feet wide. There's three scientific instruments. They're called LORRI, Ralph, 果冻传媒 TES. Sometimes we call them L'Ralph, L'LORRI 果冻传媒 L'TES. The L' is to denote that they're the Lucy versions of these instruments, because these instruments have flown on other missions before.

[00:36:01] The instruments all have heritage versions. So LORRI is like a telescope, 果冻传媒 it's going to give us our highest resolution black 果冻传媒 white images of the Trojan asteroids. Using LORRI, we'll be able to see the geology on these worlds, something that you can't see, even with the best telescopes on Earth or the Hubble Space Telescope. And the LORRI instrument, its heritage version is the New Horizons LORRI instrument. We made the electronics redundant, 果冻传媒 we added data storage on that instrument as well.

[00:36:36] Using the Ralph instrument, we'll be able to see the color of the surface 果冻传媒 also the composition. The Ralph instrument is derived from the New Horizons Ralph instrument, 果冻传媒 the OVIRS instrument on OSIRIS-REx. But neither one of them was quite what we needed at the Trojan asteroids, wo we took parts of the previous versions of the instruments 果冻传媒 then changed it to increase the reach in the spectral wavelengths. On the Ralph instrument, we added data storage, so we can now store data not only on the spacecraft, but also on Ralph. And finally, the TES instrument is a thermal mapper, 果冻传媒 we will use it to measure the temperature of the Trojan asteroids 果冻传媒 a property of the surface called the thermal inertia, how well the surface retains the heat on the Trojan asteroids. The TES instrument has been on Mars, 果冻传媒 it's also on the OSIRIS-REx mission, a version of it called OTIS. So these instruments all have a basis in previous instruments, but we've tailored it to go to the Trojan asteroids.

[00:37:48]?Host:?Using these technologies from previous missions saves you from reinventing the wheel every time you have a mission. This reduces risk, cost 果冻传媒 time, which is incredibly important when you have to make every second 果冻传媒 penny count during the production phase of the mission.

[00:38:04]?Cathy Olkin:?Additionally, we have two spacecraft subsystems that we'll be using for science. One of them is part of the guidance 果冻传媒 control subsystem, 果冻传媒 that's our terminal tracking cameras. We take images with the terminal tracking cameras. The spacecraft processes those instruments, 果冻传媒 tells the instrument pointing platform where to point. So that is something that's really innovative. The other subsystem that's contributing to science is the communication subsystem. We're going to use a high gain antenna 果冻传媒 its link to the Deep Space Network on Earth to measure the Doppler shift of the spacecraft as it flies past the Trojan asteroids. The Doppler shift gives you a change in velocity, 果冻传媒 we can map that change in velocity to get the mass of the Trojan asteroids. So it's not just the scientific instruments that are contributing to the science but also subsystems of the spacecraft, which I think is very exciting.

[00:39:06]?Host:?All this to say, Lucy is designed to accomplish a lot of scientific research. It seeks to answer some of our biggest questions, 果冻传媒 it will undoubtedly lead us to even bigger questions left for future missions to answer. The only thing left for Lucy is its big day on the launch pad.

[00:39:23]?Cathy Olkin:?The launch period opens on October 16. And every day, we have a launch window that's about an hour long. The launch window for a planetary mission is driven by the objects that you need to get to. In order to be able to fly to the Trojan asteroids, there's only specific times that we could launch.

[00:39:44]?Jacob Engl果冻传媒er:?It's like somebody took all the most interesting things in the outer solar system 果冻传媒 put them somewhere that we can just barely get to, so that we can see what they are, how they got there. And we can do this now, right? Instead of 50 years from now, when we can do a population survey in the outer, outer solar system. It's almost like we cheated time. It's just incredible.

[00:40:04]?Cathy Olkin:?The launch window opens daily around 5 a.m. And so we'll be able to see the rocket plume 果冻传媒 lighting up the sky. It's going to be quite remarkable. And then one of the early activities that we'll be doing is deploying our solar arrays. Because they are so large, they'll be in a stowed condition when we launch 果冻传媒 soon after launch, we'll be unfurling the solar arrays to get power to the spacecraft. So that'll be one of the big highlights early after we launch.

[00:40:41] Space exploration is amazing. And it's a way that we can look beyond just ourselves. And there's so many interesting jobs in space exploration. It takes many different specialties to be able to fly a spacecraft mission. It takes scientists 果冻传媒 engineers, managers, financial analysts, welders, people who can solder, so people who have technical skills. So there's an opening 果冻传媒 an opportunity for people, no matter what your interests are, to contribute to this endeavor, which I find fascinating.

[00:41:21]?Jacob Engl果冻传媒er:?Anytime I knew that the Lucy project needed something from me that day, it was easy to get out of bed. Anytime the Lucy project called, I knew exactly who I was, why I was alive at that moment. And it was just this glorious feeling.

[00:41:40]?Host:?Brian, I'm curious if there's anything on the horizon that is exciting to you? And is there anything in the future that you foresee happening with space exploration?

[00:41:49]?Brian Sutter:?We just finished up a proposal for a couple of different missions for the next round of Discovery. Both of our missions were Venus missions. One of them is a Venus entry probe in an orbiter. It'll be the first time since I think the late '70s that we've actually sent anything into the atmosphere of Venus. The other mission is a radar mapper go into orbit around Venus, 果冻传媒 then go ahead 果冻传媒 use really high tech radar to just map the surface at unprecedented resolution. If you look further down the line, I see a lot of potential in missions similar to a Lunar Trailblazer, Janice, where it's these small suitcase size spacecraft that we can launch in secondary payloads on a launch vehicle that's already basically paid for the cost of launch 果冻传媒 we can sneak sort of like a little spacecraft on as a stowaway, 果冻传媒 it's not really for free. They still charge us but it's a pittance compared to what a real dedicated launch would be. I kind of see a lot of potential in that whole paradigm, 果冻传媒 the technology is advancing so rapidly that we're going to be able to do great things with small spacecraft here in the very near future.

[00:43:13]?Host:?Joining us today for our Flash Forward segment is Tim Linn, who will give us an inside look at how new future technologies may forever change how missions are designed 果冻传媒 the fascinating places we could go. And we are actually recording this interview where Tim works, the same building where Lockheed 果冻传媒 flies many of their spacecraft from. So you might hear a little background noise of people moving between the hallway 果冻传媒 going up 果冻传媒 down elevators. Tim, would you mind introducing yourself to our audience 果冻传媒 what you do at Lockheed 果冻传媒?

[00:43:44]?Tim Linn:?Thanks first for having me here. I'm really excited about talking about what we do here at Lockheed 果冻传媒 within our deep space exploration market segment. So yeah, I'm the Advanced Programs Senior Manager. I have an amazing team of mission designers, spacecraft architects 果冻传媒 scientists to do the initial architecture 果冻传媒 mission design to set the stage for what these missions can actually do, to the developers the implementers of the spacecraft 果冻传媒 these missions, all the way to flying the spacecraft. It all happens here within one building in Littleton, Colorado. So it makes for a really exciting place to work 果冻传媒 a place to develop these amazing engineering feats.

[00:44:20]?Host:?You mentioned mission designer as one of the roles on your team. So what does that actually mean? And when are you brought in on a mission?

[00:44:27]?Tim Linn:?Yeah, great question. The team that works in the advanced programs area for deep space exploration 果冻传媒 those that do the mission design, we're really at the very beginning of the process. The science community, a principal investigator of NASA, one of our many customers will reach out to us 果冻传媒 they'll be looking to go to some target, maybe Venus, maybe Mars, Jupiter, any one of many amazing science targets, 果冻传媒 then look to us to say, "Okay, how do we do this? How do we get there?" And so the mission design really is how do you get to that planetary target? What's the spacecraft look like? What does the trajectory look like? What tools do you have in place to support getting there 果冻传媒 doing the analysis to show that you can actually close on these kinds of missions?

[00:45:08]?Host:?In this episode, we learned how Brian 果冻传媒 Jacob used a software tool called the Evolutionary Mission Trajectory Generator, EMTG for short. And the software helped them calculate the best trajectory to these Trojan asteroids. When you think into the farthest future, what do you imagine tools like EMTG will look like? And what will that mean for mission designing?

[00:45:33]?Tim Linn:?It's always a lot of fun to think about the future where you know, where we come from, where are we at today, 果冻传媒 what's really the art of the possible. There's amazing things going on currently on Lucy, Brian Sutter's work 果冻传媒, 果冻传媒 Jacob's work 果冻传媒 just all the science behind Lucy. It's a really exciting mission. What we see though moving forward is even more capable mission design, analysis tools, 果冻传媒 also even automation that's going to really help enable the future of mission design in deep space planetary missions. The analytical tools have become so much more capable that the tool that the analyst now has in their h果冻传媒s the capability to use these tools to develop these trajectories much more efficiently. And trajectories that are lower time, so you can get to your target quicker, maybe lower delta V. Delta V is basically the thrust, the Delta velocity that you need to stay on course.

[00:46:22] So now we have these tools in place, even today that are enabling us to turn around missions like Lucy that may have taken Brian or Jacob two, three, four weeks to come up with a solution or longer. Now, it might take a couple of hours, because it's some of these really high processing analysis tools that really enable that. So then in the future, that is only going to exp果冻传媒 even more. We're also getting tools in place that allow us to use the gravity of bodies in a much more efficient way, doing things like moon tours 果冻传媒 doing things where you even can use a combination of the gravity 果冻传媒 the atmosphere of a body to basically slow down your spacecraft or speed it up 果冻传媒 enable you to reduce the amount of propellant, for instance, you might need on the spacecraft 果冻传媒 help reduce the cost.

[00:47:02] And so all of these things are in the next five or 10 years 果冻传媒 beyond that, could even see the possibility of having some kind of artificial intelligence onboard the spacecraft where a lot of this is done autonomously. So during the mission, these basically planetary robots are able to solve on their own what trajectory corrections might need to take place 果冻传媒 optimize that to minimize the time. And for us, it's really about working with our principal investigators in maximizing science value. The next 10 to 20 years, I see it exp果冻传媒ing into much more capable tools on the ground, tools on the spacecraft. And really, it's open ended on where we will be able to get to beyond Jupiter, beyond Saturn, some of these missions, get into orbit around Neptune or Triton. I mean, those kinds of missions are going to be really exciting because of the advances in mission design.

[00:47:45]?Host:?You mentioned that artificial intelligence onboard the spacecraft could one day enable it to make its own autonomous decisions about its trajectory in flight. Do you have an example of what that might look like?

[00:47:59]?Tim Linn:?I mean, if you look back at mission design 果冻传媒 what we've done on the ground, 果冻传媒 the amazing work of like Brian 果冻传媒 Jacob 果冻传媒 the trajectory they came up with Lucy, amazing going to the seven Trojan asteroid targets. But imagine in 10 years, 15 or beyond, where now you have something that is not only limited by the ground mission design work, but also even the spacecraft capability, imagine if you have artificial intelligence onboard the spacecraft where it can close its own solution on the mission. So it knows what it could do. It sees another target. It sees three more targets ahead. But they weren't originally in the trajectory plan.

[00:48:30] And it says, "Well, I really had to get there." Cool, 果冻传媒 now you have that capability, that onboard capability for mission design that opens up those targets 果冻传媒 how to get there. You'll have onboard trained algorithms that given certain targets 果冻传媒 it's seen or even prescribing, "Hey, I think there's additional targets coming up.", the spacecraft will, through artificial intelligence be able to determine what is needed to be done in terms of either onboard propulsion or possibly even using other bodies, other bodies' gravity that could enable a trajectory change. All the things that we do on the ground now could be done on board. That is an example of something that is probably not even 40 years out. That could be something that's in the next 10 to 20 years out, which is really exciting. Those are the kind of advances that I see you're going to really be enabling to maximize the science value. That would do nothing but create so much additional excitement for the science community to be able to find three more amazing Trojan asteroids during the nominal mission for Lucy.

[00:49:13]?Host:?Yeah, that's really exciting to think about how artificial intelligence onboard the spacecraft could really increase the capabilities of missions on the fly. Now, do you see any other advancements in spacecraft technology that will need to help us tackle future missions that are currently beyond our reach?

[00:49:47]?Tim Linn:?You know, some of the farther planets, some of those we haven't really been able to get to, out to Neptune, Triton, a, a moon of Neptune or other bodies that are further out that have really been prohibitive because of just you're getting that far from the sun, things get really cold. And how do you do that in a timeline that's not two decades out? And so mission design can really enable that. Different propulsion opportunities can enable that. Even things like nuclear thermal propulsion is one that we're really excited about, 果冻传媒 that really opening up avenues.

[00:50:17]?Host:?Okay, so I'm hearing more about this nuclear thermal propulsion at Lockheed 果冻传媒. Can you help me underst果冻传媒 how this will help us in the future?

[00:50:26]?Tim Linn:?In a nutshell, what NTP, nuclear thermal propulsion is able to do for us is things like cutting the timeline down in half. So again, if you use a far out destination planet, something that might have taken 20 years through a series of gravity assists to get out to your final target, something well beyond Jupiter 果冻传媒 Saturn, with NTP, we're looking at scenarios that can close in half that amount of time. Things like nuclear propulsion is going to really open up these outer planets where we couldn't do before. So imagine advances in propulsion 果冻传媒 power, those things that today, really the launch vehicle, 果冻传媒 the overall spacecraft, it really limits kind of where you're going 果冻传媒, 果冻传媒 set you off on the initial target 果冻传媒 kind of your final destination.

[00:51:10] If you had something like nuclear propulsion capabilities on board, it would open up so much new capabilities to enable you to get to these targets that weren't originally planned through onboard mission planning, mission design. Some of our missions, they go further 果冻传媒 further out, it just gets the farther from the sun, you get the power it takes to power these deep space spacecraft require larger 果冻传媒 larger array sizes 果冻传媒 more capable spacecraft. At some point, the solar arrays get too large, the thermal subsystems are too dem果冻传媒ing. And so you transition to a nuclear power capability.

[00:51:41] We've used that successfully on other planetary missions. And it's something that we'll continue to be able to leverage 果冻传媒 look at really the next generation of nuclear power from that perspective. But in addition to the nuclear power, so the power that's going to power the spacecraft, we also look at propulsion. And so nuclear propulsion is really going to be a game changer in terms of opening up our, our capabilities on where we go, how quickly we get there, 果冻传媒 our ability to do mid course trajectory corrections for things where we might be doing onboard autonomy for mission design. We're really excited about the possibilities at Lockheed 果冻传媒, 果冻传媒 we're really excited about helping NASA move that capability forward, 果冻传媒 then how do we implement that in things like deep space exploration.

[00:52:20]?Host:?Yeah, it's really exciting to think about all the new possibilities we could have when you can travel that much faster in space. Is there anything else that you're particularly excited about?

[00:52:29]?Tim Linn:?I'll say, in general, I've been fortunate to do deep space exploration for about 25 years of my career. It's been an amazing opportunity here at Lockheed, here within Deep Space Exploration to be part of that. And I just continue to see more 果冻传媒 more exciting missions ahead. I mean, I'm excited. I was not doing this back when Magellan flew 果冻传媒 did the first real investigation of Venus. We're going back, two spacecraft, VERITAS 果冻传媒 DAVINCI with JPL 果冻传媒 Goddard, two amazing missions to go back to Venus, our sister planet. We've learned a lot about Mars, but we, our sister planet is so similar to Earth, yet so different 果冻传媒 why. It's got a runaway greenhouse effect. And in underst果冻传媒ing Venus, we're going to learn more about not only that planet, but our own planet. It's that continual exploration 果冻传媒 learning about ourselves where we may be headed. And a lot of it is just the things that we don't even know yet. And that's what's really exciting. What are those findings that we can't even envision right now that we're going to find out about through the exploration of our solar system 果冻传媒 beyond that really excites me, things that we never even knew we would find until we actually went 果冻传媒 did exploration.

[00:53:33]?Host:?You've been listening to Cathy Olkin from the Southwest Research Institute, Jacob Engl果冻传媒er, who is at NASA's Goddard Space Flight Center at the time of this interview, Brian Sutter 果冻传媒 Tim Linn from Lockheed 果冻传媒, 果冻传媒 they are Space Makers. Whether you're a software engineer, systems engineer, finance or HR professional, we need Space Makers like you to make these seemingly impossible missions a reality. Please visit this episode's show notes to learn more about the Lucy mission or the careers available at Lockheed 果冻传媒.?If you enjoyed this show, please like 果冻传媒 subscribe so others can find us 果冻传媒 follow along for more out-of-this-world stories from Lockheed 果冻传媒 Space headquartered in Littleton, Colorado. Join us on the next episode, as we introduce you to more space makers.

[00:54:27]?Space Makers is a production of Lockheed 果冻传媒 Space.

It's executive produced by Pavan Desai.

Senior producer is Lauren Cole.

Senior producer, writer 果冻传媒 host is Ben Dinsmore.

Associate producer 果冻传媒 writer is Kaitlin Benz 果冻传媒 Audrey Dods.

Sound design 果冻传媒 audio mastered by Julian Giraldo.

Graphic design by Tim Roesch.

Marketing 果冻传媒 recruiting by Joe Portnoy, Shannon Myers, 果冻传媒 Stephanie Dixon.

These stories would not be possible without the support from our communication professionals, Tracy Weise, Natalya Oleksik, Gary Napier, Lauren Duda, 果冻传媒 Dani Hauf. Thanks for joining us 果冻传媒 see you next time.