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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #15 dnia: Marzec 12, 2023, 05:17 »
Gravity Assist: Let’s Talk About Climate Change, with Gavin Schmidt (2)

Jim Green: Well, to understand this concept of altitude of land isn't it true that as, as ice or snow in mountain peaks then wither away, the land becomes more buoyant and moves up. And so you have to not only factor in the, the change in ocean height, but the change in, in mass that is occurring on the land.

Gavin Schmidt: Yes, you do. And in fact, it's even more complicated and more fascinating. Because when you when you move the ice, when the ice moves, and it melts and goes into the ocean, you're also changing the mass distribution on Earth, which changes gravity. And so if you lose a chunk of ice on Greenland, that means that there's less gravity pulling water towards Greenland. And in fact, sea level goes down near Greenland, and goes up elsewhere. And, and it turns out that there's a small change in the rotation of the Earth as well, which also changes the shape of the geode, and you need to have all of those things calculated, if you're going to be able to predict what's going to happen to sea level in New York, or in Johan-- or in South Africa, or also or in or in Shanghai. And each of those places has a different fingerprint from where the ice is melting, or where the terrestrial water storage is changing.

Jim Green: Gavin, what lessons should we take away from the climate environment during the global pandemic?

Gavin Schmidt: Okay, so let me start off by saying that I'm not going to recommend a global pandemic in order to reduce emissions.

Jim Green: Good, good, good.

Gavin Schmidt: Nonetheless, the restrictions that were put in place, it did impact a lot of different emissions. So as you rightly say, you know, we, in the US, we reduced carbon dioxide by I think about 10%, in 2020, compared to the year before, globally, it was about a 7% decrease in carbon dioxide emissions, mostly from changes in transportation. So people weren't driving as much they weren't flying as much. And, and that had impacts on other things, too. So, so people not driving reduce the amount of nitrous oxides. So those are a precursor of smog, there are very bad, health wise, in cities, mostly everywhere, we saw reductions in ozone, and not, not so much in some of the most polluted parts, but, but we saw big changes in in the short-lived pollutants that we that we saw from space, everywhere, where there were big restrictions put in place.

Gavin Schmidt: So there's, there's two lessons, I think, to take from that. One is that just making people stay at home and not do anything, is not a good climate plan. Right? That's, that's, it's not sufficient. The systematic changes that need to be made in how power is generated and how industry is run. Those are the big players and, and without tackling those, you know, individual choices about you know, working from home or going into the city or taking a car or taking a bus taking a bike, all of those things are small comparatively.

21:25 Gavin Schmidt: The second thing to learn from that, though, is that anything that we do that is going to reduce emissions is always going to affect these other things. It's also going to affect air pollution, it's also going to affect smog. And there are things that we can design there are, there are policies that we can design that allow us to reduce emissions and clean up the air at the same time, and reduce, you know, public health problems associated with particulates or with ozone or with smog. And so these things are connected. And I think the, you know, one of the most important lessons from, from the COVID pandemic has been: Those connections are very, very clear. And we need to be able to build those into our, our plans going forward.

Jim Green: So in terms of being a good steward of this planet, are there things that individuals could do that would help out?

Gavin Schmidt: It's important to remember that even though you're an individual, you wear many hats, you know, you're, you're an individual consumer. You're a commuter, you can, you can work from home or take a bike or take public transport, rather than driving a car, you can swap out your car for an electric vehicle. You can be a citizen, you know, you're you can be a parent, you can be a member of a faith community. And through those communities, you can influence decisions that are being made at a higher scale, right? You can influence the, the insulation that that's being put into the school or your new building, you can influence where your town buys its energy, you can influence the politicians that are making decisions about utility choices, you can influence, you know, the readers of your local newspaper. You can influence the people at your local town halls, you have a lot of different roles that are there that can amplify your values and your choices, such that they can impact bigger and bigger and bigger decisions.

Jim Green: So everyone can play a role and an important one at that.

Gavin Schmidt: Yep.

Jim Green: Well, you know, Gavin, I always like to ask my guests to tell me, what was the event or person, place, or thing, that got them so excited about being the scientists they are today? I call that event a gravity assist. So Gavin, what was your gravity assist?

Gavin Schmidt: So back when I was a postdoc, I was working at McGill University in Montreal. And Montreal, as I'm sure you know, is is bilingual, right? So there's, there's an English population, there’s a French speaking population. And I’m fortunate enough to speak a little bit of French and so I was able to kind of, you know, go between the two. And, and I remember, you know, pretty early on, when I was there, I was giving a talk, and it was a, it was a French language scientific conference, and I was giving a talk on the Cretaceous, and what, and how the climate of the Cretaceous might have been. And immediately after I gave my talk this, this, this, this journalist came up to me and, and he said, Oh, you know, I'm from from Radio Canada, which is the French, the French network there.

Gavin Schmidt: And he says, you know, my audience is absolutely fascinated by by the Cretaceous, you know, because, you know, there were dinosaurs, and everybody loves dinosaurs. And, and he said, You know, I just, you know, can you tell me something about the predictions? So, he, you know, the camera starts rolling. And this is all in French. And the guy says, What would he says to me, you know, “Comment était le crétacé?” So, what was it like in the Cretaceous? And I said, “Chaud.” Hot. And he says, you know, how hot? I said, “Très chaud,” very hot. And he said, Thank you very much. And that was it. And I was going, Okay, well, that was that was that was interesting.

Gavin Schmidt: And, and, you know, and I bring that up, because, you know, what's kind of pushed me to be kind of where I am, as has been a kind of innate desire to help people out to explain stuff to folks. And one of the things that I realized at that moment was that even if I don't know everything, I still know a lot more than a lot of other people. And that's kind of the need to know a lot about the need to know a lot about a lot of things, and see how they fit together. And then be able to explain what's going on in the ocean to the people that care about the clouds, or what's going on in the radiation to the people that care about paleoclimate or explained to somebody that cares about the dinosaurs how climate change, you know, impact or impacted or impacted them. You can be that translator, you can be that conduit of interesting information. You know, that was that was when I kind of realized that that was something that could be done. And that, and that I could do it.

Gavin Schmidt: What's pushed me into climate change has been both that kind of evolution of, of my thinking about what science is for, but also this massive interest that the public and another people have about climate change.

Jim Green: Well, I gotta tell you, you really upped your game since that last interview. (laughs)

Gavin Schmidt: Well, it’s a craft, yes.

Jim Green: Yeah, that's right. And and indeed it it takes a lot of practice and a lot of exposure. And, and it's hard for scientists to talk about, you know, some of these esoteric subjects.

Jim Green: So Gavin, thank you.

Gavin Schmidt: Thank you very much.

Jim Green: Will join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green, and this is your Gravity Assist.

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Jun 18, 2021
Editor: Gary Daines

« Ostatnia zmiana: Marzec 19, 2023, 06:17 wysłana przez Orionid »

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #16 dnia: Marzec 26, 2023, 08:10 »
O źródłach misji Psyche

Lindy Elkins-Tanton: Because, you know, it seems like a very, very niche topic to discuss, doesn't it? But to those of us who are in planetary science, it was kind of a big idea. And so we presented at conference and we have people lined up at the microphones before we even started talking, it was standing room only there were hundreds of people crammed in the room. Because for the 200 people in the world who care about this, it was a really big and controversial idea. And so that's what got us thinking, how do we look inside a planetesimal? And that's what eventually led us to Psyche.

Gravity Assist: This Asteroid Is Metal, With Lindy Elkins-Tanton (1)
Jul 2, 2021

This illustration, created in March 2021, depicts the 140-mile-wide (226-kilometer-wide) asteroid Psyche, which lies in the main asteroid belt between Mars and Jupiter. Psyche is the focal point of NASA's mission of the same name. The Psyche spacecraft is set to launch in August 2022 and arrive at the asteroid in 2026, where it will orbit for 21 months and investigate its composition. Credits: NASA/JPL-Caltech/ASU

What’s inside a planet? We can’t drill into the center of Earth. But with the upcoming Psyche mission, scientists will have the opportunity to visit a unique object in the asteroid belt called Psyche, which may be the exposed metallic core of a planetary body that stopped growing before it became a big planet like Earth. Dr. Lindy Elkins-Tanton describes her fascination with Psyche as well as the rock record here on Earth. 

Jim Green: A mission to the most mysterious asteroid in the asteroid belt is getting ready to fly. What is that object? And why is it important for us to explore it?

Lindy Elkins-Tanton: It’s probably the first metallic object we humans will ever go visit.

Jim Green:  Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Dr. Lindy Elkins-Tanton and Lindy is the vice president of the Arizona State University's interplanetary initiative. And she is also the principal investigator of the Psyche mission. Now, Psyche was selected in 2017 when I was head of planetary science. 

Lindy Elkins-Tanton: (laughs)

Jim Green: Yes, that's right. And it has a window to launch beginning in August 2022. So Lindy, welcome to Gravity Assist. 

Lindy Elkins-Tanton: Thank you so much, Jim. It's really great to join you here. 

Jim Green: Well, you know, your background in geology and geochemistry is really fascinating, you know, because you specialized in the formation of terrestrial planets. So how does the rock record really give us insight into how our terrestrial planets form?

Lindy Elkins-Tanton: The question is, what rock record are we talking about? Because for centuries, for millennia, we tried to understand our Earth by looking at the rock record we have here on Earth. And it turns out, it doesn't go back far enough. Our oldest rocks on Earth are really about 4 billion years old. But that is several hundred million years after the formation of our planets, it turns out, because of our weathering, and our plate tectonics and all the things that happen on the surface of the Earth, we don't have the record of the very early formation of planets. So for that, we have to go to meteorites, the remnants, the shrapnel of planet-forming, and we need to leave the Earth and look at other planets and asteroids that have earlier surfaces. 

Jim Green: So indeed, we had to brin rocks back from the Moon and find out that they were older than the oldest rocks here on Earth to really tease that out.

Lindy Elkins-Tanton: Exactly. That's exactly right. And so then we were able to get some information about when the Moon formed, but then to find out when the majority of the Earth formed before that, and also when Mars formed really, really early. And then the very earliest bodies in the solar system, the ones that I really love these days, planetesimals, meaning little planets, these little planets that formed in just the equivalent of if our solar system was 24 hours long, they would have formed in the first 10-20 seconds. And they're really the materials like the raw materials like the eggs and the flour from which our big planets were formed. And so it turns out, there are stages and stages of earlier and earlier information we can get. So starting with the Moon earlier, than the, than the Earth's surface that we have today, and then stepping backwards in time even further.

Jim Green: Well, you know, one of the things that we recognize as humans here on Earth, is that species come and go. Is there evidence of that in our rock record?

Lindy Elkins-Tanton: Yes. All right. So here's what our rock record on Earth is amazing at, is telling us what has happened on our Earth in the last 3 to 4 billion years. But even better at doing it in the last, say, 700 million years, just the most recent, say, one-fifth of our Earth's age. And by looking at those rocks, we can see the record of species developing, you can see their fossils in the rocks, and then fossils disappear with younger rocks. And we know that species went extinct, and then new species show up. We can track the branching and the extinctions of life on Earth by looking at the rocks. 

Jim Green: Now, you did some fieldwork and collected samples when you were looking at extinction events. 

Lindy Elkins-Tanton: Mhmm. 

Jim Green: What was your most memorable field experience?

Lindy Elkins-Tanton: Oh, my goodness, those experiences were unbelievable. I was just, I was just chatting about this with my husband last night. Amazingly, I spent five field seasons in Siberia in very remote places, finding samples of rocks with a big team, eight nations, 30 scientists, all different disciplines, because you need everybody at the table to answer these questions. Trying to understand if the world's largest ever volcanic event, the Siberian flood basalts, caused the world's largest ever extinction event, the end Permian extinction. And just when I say it like that, probably your response is, “Well, duh, like that seems like it would be pretty obvious that that could happen.” 

Lindy Elkins-Tanton: But exactly how the volcano could cause the extinction really wasn't clear. So we spent lots and lots of time selecting those rocks and bringing them back and analyzing them and getting our answers. But so memorable. And I was just, what I was saying to my husband last night is that is that an adventure is what you call it when it wasn't a tragedy. (laughs) 

Lindy Elkins-Tanton: And we had so many adventures going down these big Arctic rivers in like ridiculous inflatable boats and flying in planes that turned out the seats weren't bolted to the plane, and being out, you know, hundreds of kilometers from any person, hundreds of kilometers from any railroad or road. And really, they were some of the most amazing experiences of my life. 

Jim Green: Well, I’m so glad you made it through that, so that it wasn't a tragedy. But indeed wasn't the end of the Permian a big tragedy?

Lindy Elkins-Tanton: I guess it was a big tragedy. That was the biggest extinction that we have recorded. So far in Earth history. We lost, maybe above 95% of ocean species all went extinct, leaving just a few percent left. And at least 70% of land species went extinct. It was pretty close to the end of multicellular life on Earth for a while. Recovery came very quickly. But it was a very, very dramatic event. 

Lindy Elkins-Tanton: And one of the things that went extinct people often ask me, well, Wasn't this the dinosaurs? No, not the dinosaurs. Before the dinosaurs. dinosaurs hadn't even come to exist yet when this happened. So what exactly went extinct? Well, one thing that went extinct, which is one of my favorite animals of the past, was trilobites. They look a little bit like horseshoe crabs, but they're quite different organisms. And there were so many of them, and they all went extinct. That was the end of trilobites.

Jim Green: So in the last 500 million years, there's been, what? Five extinctions? Where's the Permian in that set?

Lindy Elkins-Tanton: Right? The five big extinctions? Well, the famous dinosaur one is about 66 million years ago. And the Permian was 252 million years ago. And an interesting thing about it is that these five extinctions when you think about it always being an asteroid strike, which was certainly a big contributor with the dinosaurs. The other ones all seem to be more related to big volcanic eruptions, and in fact, the global climate change they caused by changing the chemistry of the atmosphere. 

Jim Green: Well, I tell you, you know, we are the first species on this planet that recognize we can become extinct. 

Lindy Elkins-Tanton: Yeah.

Jim Green: We're also the first species that actually could do something about it. 

Jim Green: Everyone associates, you know, the extinction of the dinosaurs with a major impact event. 

Lindy Elkins-Tanton: Mmm. 

Jim Green: You know, an asteroid that's come to us. So this brings us to, I think, another really super topic that connects well, and that's your Psyche mission. 

Lindy Elkins-Tanton: Psyche! 

Jim Green: Yeah. So what exactly is Psyche? And what do we know about it so far?

Lindy Elkins-Tanton: Oh, my goodness. This is so fun to talk about. Psyche is the name of an asteroid that orbits out past Mars, in the outer main asteroid belt between Mars and Jupiter. And it is also the name of our robotic spacecraft that is going to visit this asteroid Psyche. Psyche was named after the goddess Psyche, by the man who discovered this asteroid back in the 1800s. Now, what do we know about Psyche? Surprisingly little, which makes it an incredibly fun kind of exploration to do. We're so privileged as planetary explorers to send robots to Mars and learn more about Mars to send robots and soon humans to the Moon, again, to learn about the Moon. 

Lindy Elkins-Tanton: But what about going to a place where we've never been, and where we've actually never had a close-up photograph? We don't even really know what it looks like. So we're exploring a whole new kind of object where we don't have any answers yet. What we know so far is that it's unusually dense. It's so dense that it can't be just made of rock. It has to also be made of metal and so it makes it probably the first metallic object we humans will ever go visit. 

Jim Green: Well, Lindy, when was the first time you recognized that Psyche was so special, and that we needed to go out and visit it?

Lindy Elkins-Tanton: You know, it was after we started planning the mission. And I think a lot of people think of that as backwards. You know, that the principal investigator and the team of people. At one point we were 800 people, by the ways, big teams. Think that you start with this idea. I'm going to the Moon, I'm going to Mars, I'm going to Ceres, but actually we started with the science question. People were interested in a paper that we'd written in a hypothesis we had about how planetesimals form and it took us a few months to decide that the very best place in our whole solar system we could go to learn about this science question was Psyche. So the science question came first. And then Psyche came second.

Jim Green: Wow, that's interesting. (laughs) 

Lindy Elkins-Tanton: Back in 2011, I published a paper with my friends Ben Weiss and Maria Zuber, thinking about what the structure of these little planetesimals these tiny planets could be. And it had been generally thought that they either melted entirely and had a rocky exterior and a metal core, or they didn't melt at all. And we started working on could they melt partly, could they have a metal core inside, but then an unmelted lid on the outside, which matches a bunch of observations of meteorites. And this is the kind of thing, this cracks me up to talk about. 

Lindy Elkins-Tanton: Because, you know, it seems like a very, very niche topic to discuss, doesn't it? But to those of us who are in planetary science, it was kind of a big idea. And so we presented at conference and we have people lined up at the microphones before we even started talking, it was standing room only there were hundreds of people crammed in the room. Because for the 200 people in the world who care about this, it was a really big and controversial idea. And so that's what got us thinking, how do we look inside a planetesimal? And that's what eventually led us to Psyche.

Jim Green: So how does one get all this metal together?

Lindy Elkins-Tanton: Yeah. Why is there a big chunk of metal out there? Well, I can tell you with some confidence, it's not the Death Star because those who know the Death Star say the size is not correct. So how do we collect metal? Well, that is a natural process of making rocky planets. It turns out that we know this from meteorites, that the most primitive material just like the building blocks of planets has little bits of metal and little bits of rock all mixed together really intimately like, centimeters, millimeter size grains. And when you put all that material clumped together into a planetesimal, to return to that tiny planet idea, the little bodies that formed early, I mean things that are 10s or hundreds of kilometers in diameter, like the size of a state, maybe the size of Australia, they’re heated up by those early short lived radioisotopes. Turns out there was enough of one of them aluminum 26 to actually melt those planetesimals. So when you melt the mixed up rock and metal, in a body the size of Australia, the metal sinks to the middle because it's denser. And that's how you get a big clump of metal. We've got a big clump of metal, our core, inside of the Earth. There's one inside of the Moon, amazingly, inside of Mars inside of Mercury, inside of Venus, but we never, ever get to see them. It's too hot. It's too pressurized. Like, no matter what Jules Verne says, we are never going to go to the Earth's core. So Psyche gives us, we think, a way to see the core of a planetessimal, maybe the only way humans will ever see a core if our ideas are right.

Jim Green: But that tells us that the metal must be exposed for us to be able to…

Lindy Elkins-Tanton: Mhmm. 

Jim Green: … when we get there see it on the surface. How did that happen?

Lindy Elkins-Tanton: Oh, okay, so they're so Psyche went through something that really went beyond an adventure a bit into a tragedy. And we think this is our best idea. We think that that's Psyche was part of a planetesimal. And it had that metal core and that rocky outside, and that as it collided with other planetesimals rather than clumping up into bigger and bigger things like the Earth, instead, it got bashed into pieces. And so its rock was bashed off of it and some of its metal was exposed. Maybe it's all metal, it could be all metal, it could be half metal, we really are not sure. But we think it must be a fragment of a larger body that finally had its metal revealed on the surface through impacts that were destructive to it.

Jim Green: Well, you know, this really makes sense to me. Because, you know, when I was in grade school a long time ago, I was told that the asteroid belt was where two planets collided, and here's the debris. But isn't it true that the asteroid belt is actually trying to become a planet…

Lindy Elkins-Tanton: (laughs) Right.

Jim Green: But Jupiter is not letting it.

Lindy Elkins-Tanton: Yes.

Jim Green: It's pulling those pieces apart?

Lindy Elkins-Tanton: That's exactly right. And you know, that idea that there was a planet there has been around for centuries. And it turns out that if you clumped up everything in the asteroid belt, it would be just really tiny, it wouldn't even make a planet even if you get it together. But Jupiter is the great disrupter, you're right. Its gravity interacts with the asteroid belt objects and keeps them apart. And so in fact, there's really lovely dynamical work done by theorists who can show that Jupiter actually starved Mars. It disrupted the material in that area so much that Mars could not grow beyond its you know, we don't like Mars to feel bad, but small size.

Lindy Elkins-Tanton: And this idea, you know, what is the asteroid belt and where is the planet that belongs there is something that has been around for centuries and, and in the early 1800s. This is just my favorite story about asteroids, that… that Franz Xavier von Zach in Germany, organized all these astronomers all over Europe into a team to find the missing planet. And they started searching because at that time, they didn't know about asteroids they hadn't been seen yet. And so they just saw a big blank space between Mars and Jupiter. And the reason I love this story twofold. One is that their nickname was Die Himmels Polizei, the, the celestial police is how people translate it, they were going to set the heavens straight, they were going to set them to order by finding the missing planet. And then they started looking at one of the things they found was Psyche. So thank them for looking.
« Ostatnia zmiana: Kwiecień 09, 2023, 10:22 wysłana przez Orionid »

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #17 dnia: Marzec 26, 2023, 08:10 »
Gravity Assist: This Asteroid Is Metal, With Lindy Elkins-Tanton (2)

Lindy Elkins-Tanton is a planetary scientist with expertise in planet formation and evolution. She is the Principal Investigator for NASA’s Psyche mission, the first NASA mission ever to explore a metal-rich asteroid. Credits: Abigail Weibel

Jim Green: Yeah, in fact, the first set of things they found like Ceres and Vesta, 

Lindy Elkins-Tanton: Exactly.

Jim Green: They thought they were planets.

Lindy Elkins-Tanton: Right? Right. Maybe they're just really far away. And they're big planets. But now they're just little sparks of light. So, asteroids.

Jim Green: Right. And that led them to believe that there's a field of smaller bodies. 

Lindy Elkins-Tanton: Mhmm. 

Jim Green: Well, how many of these smaller bodies do we expect out there? In the asteroid belt?

Lindy Elkins-Tanton: Well, I think that we're, we're expecting in excess of a million. And as much as as those numbers just boggle us to think of, a million objects orbiting there, the fact is, it's really mostly empty space. Space is really, really empty. Even finding another asteroid that we could look at from a distance as we sent our spacecraft to Psyche, it turns out there was just nothing nearby, even with, you know, a million objects, it's just space.

Jim Green: So we really have to reorient ourselves from the Millennium Falcon flying through the asteroid belt, to then be able to realize if we can get to one, that's the that's the goal of the Psyche mission.

Lindy Elkins-Tanton: Exactly, exactly. And that Millennium Falcon image is just in our brains permanently. It's very hard to get away from that.

Jim Green: Well, what instruments are onboard the spacecraft and really be able to look at the body and tease out what it's all about?

Lindy Elkins-Tanton: It was such an interesting challenge to go through the the process of trying to figure out what instruments would allow us to measure what we needed to measure no matter what Psyche ended up being. Because there's a there's a wide range of possibilities. Here, we have our favorite hypothesis, but there's other ideas. So in the end, what we settled on was, first of all, magnetometers on Psyche, because if it was a core, and if that core made what's called a dynamo, and created a magnetic field, like we have on Earth, created by our core, then we should be able to measure its record. Won't have one now. 

Lindy Elkins-Tanton: Very cold, nothing happening on Psyche now. But the record of the past. We could use the magnetometers for that. Then we're sending imagers, of course, because we always want to know, what does it look like. And the imagers also allow us to create a topographic map of all the hills and faults and impact craters and all the things we hope to see there. And again, we don't really know. And then our third instrument is what's called a gamma ray and neutron spectrometer. And this is this is an instrument that I did not have a lot of experience with before this planning process started. And I think it is just such a miracle of ingenuity. And should I take us just a second and describe what this instrument does, because it's so incredible? 

Lindy Elkins-Tanton: So there are these things called galactic cosmic rays. And we think they are created in the middle of galaxies in their black holes, and they go shooting out through all the star systems in between galaxies and two other galaxies. They're these little tiny, super energetic particles. And sometimes they hit a body that has no air on it, like Psyche. They hit the surface of this airless body. And what they do with the galactic cosmic ray, when it hits Psyche, it hits an atom on Psyche’s surface. And that atom then gives off to other pieces of radiation: a neutron and another gamma ray. And we have our spacecraft orbiting fortuitously around Psyche with a special crystal to intercept the gamma ray and a special tube to intercept the neutron.

Lindy Elkins-Tanton: And it turns out that those gamma rays have exactly the energy of the atom that gave them off. And so by counting those gamma rays, produced by cosmic rays that come possibly from other galaxies We are able to count up and know exactly what the atoms are that make up the surface of Psyche and, and figure out its composition. And to me, that is just astonishing innovation. 

Jim Green: That's a great instrument. Now, Psyche is at least a 30-light minute trip away from Earth. So that means it's very far out there. So we got to have enough fuel one propellant to get there. What are some of the really creative ideas that came out that allowed Psyche to get out to the asteroid Psyche, way out in the asteroid belt?

Lindy Elkins-Tanton: Right, right, so, so very often of spacecraft are trying to go far away from the Earth, they might have a radioisotope power source. But that was not an option for us. Too expensive, not something we were going to create for this mission. And so, and so how are we going to do it? How are we going to be able to have enough propellant to get all the way out there? Well, we rely on this beautiful, I sort of think of it is as like as like the sustainability option for space travel. It's called solar electric propulsion. 

Lindy Elkins-Tanton: So what we're doing is we're flying huge solar arrays that will unfold from the spacecraft after launch into things that look like huge wings. They would cover a whole singles tennis court, 20-odd meters across. And at Earth, these solar panels will create 20 kilowatts of energy, out of Psyche about a 10th of that. And so what do we do with all that power, what we do is we power little thrusters called Hall thrusters. And the propellant that we use is the noble gas xenon. We're going to bring over 1000 kilograms of xenon with us in a big tank. And we take that electricity from the solar arrays, and we ionize individuals, xenon atoms, we pull an electron off of them. And then we shoot them out the back of the spacecraft through these Hall thrusters in what's called a little a little potential, in other words, that the charge of the atom will drive itself out of the out of the hall thruster, and that little tiny atom gives a little tiny push to the spacecraft. And so we do that over and over again. And we're going to go very slowly and at very high efficiency, all the way out to Psyche using solar electric propulsion, and the noble gas, xenon. And I just want to tag on to this, that this is all made possible for this mission by our fantastic industry partner Maxar, because they have vast experience in building just this kind of power system and chassis for Earth orbiters. Only this time, we're going to send it all the way out to Psyche.

Jim Green: Well, I also know that you're going to use another technique, which is flying by Mars.

Lindy Elkins-Tanton: Oh!

Jim Green: And now why do you do that?

Lindy Elkins-Tanton: We do it so that we can shout out “gravity assist!” (laughs)

Jim Green: Absolutely. (laughs)

Lindy Elkins-Tanton: That’s the whole point here. Yes. So great. So Mars is in fact going to give us a gravity assist. You know, people always say, and it's a beautiful metaphor, if you're holding hands and ice skating and one person stops and the other person slings around them and then speeds up tremendously -- that's what Mars is going to do for us. And so we're going to fly by Mars, and it's going to give us a gravity assist and send us on our way to Psyche.

Jim Green: Yeah, that's fantastic. Well, I can't wait for the launch window to open up. August of 2022. Oh, my gosh.

Lindy Elkins-Tanton: I know that it's over a year away. But it feels like tomorrow. And you know better than I do, how this goes every single day as scheduled. You know, hour by hour between now and launch. There's so much still to do. But we're going strong.

Jim Green: Well, we know you're in for a whole series of surprises when you get there. But what's the top thing that you would like to learn about Psyche? 

Lindy Elkins-Tanton: Well, our number one science objective is to figure out whether or not Psyche is a core. Is it part of that metal middle of a planetesimal? But here's my secret favorite thing. My secret favorite thing is that all our ideas about Psyche are wrong. And when we get there, we're going to discover a kind of material and a kind of body that we had not anticipated. And it'll teach us something entirely new about how planets are formed. That's my secret wish.

Jim Green: You know, I think you'll be right. Well, Lindy, you know, I always like to ask my guests to tell me what that event or person, place ,or thing that got them so excited about being the scientists they are today. And I call that a gravity assist, of course. So Lindy, what was your gravity assist?

Lindy Elkins-Tanton: Oh, this is a really lovely question to answer and I don't, I'm going to tell you right now I have a little bit of a narrative about it. I don't have just a single answer. So many people have told me their gravity assist was seeing Saturn or seeing Jupiter through a telescope when they were 10, 11, 12 years old. Like, so formative. I saw Saturn when I was 10 I think and I still wanted to be a veterinarian. 

Lindy Elkins-Tanton: So when did my gravity assist come along? It wasn't until much later in my life when I realized that the thing that transformed my own life and gave me huge impetus to keep working in this direction was the ability to work on a team of people, where the thing we were producing was so much more than what any one of us could do alone, and where we had a big aspirational goal. And those things together add up to just making me want to jump out of bed in the morning and get the thing done and feel like we really have meaning and purpose. And it's hard to imagine, for me, a bigger and more motivating goal than expanding human knowledge by visiting a place we've never been. And so that's, that's my gravity assist, is working with the team after I realized in my 20s that that was what really made me happy.

Jim Green: Well, Lindy, thanks so much for joining me in discussing this fantastic topic, the asteroid belt, and the history of the Earth and our rock record and what we can learn by visiting one of the most mysterious asteroids in the asteroid belt. Thank you.

Lindy Elkins-Tanton: Jim, thank you so much. 

Jim Green: You're very welcome. Well join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green, and this is your Gravity Assist.

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Jul 7, 2021
Editor: Michael Bock

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O historii Mars Ingenuity helicopter

MiMi Aung: And so he turned to René and me, and he says, “Why aren't we doing, you know, things like this at Mars? Why aren’t we flying at Mars?” So, from the division position, we connected Dr. Elachi with Dr. Bob Balram, right, who had done research at JPL on, you know, Mars helicopters in the 90s. And so, Bob and Dr. Elachi and Dr. Jakob van Zyl, who was you know, the associate director of strategy at the time, and they kind of, you know, quietly said “Hmmm, this, it may be worth, you know, investigating.” Well, over that year, Bob's analysis did show that perhaps with the advancement of technologies now, you know, his research was in the 90s. Now, in the 2013 era, technology maybe may have advanced that maybe we can build an autonomous system light enough that we could, perhaps build the Mars helicopter.

Gravity Assist: A Dream, a Team, a Chance to Fly on Mars, with MiMi Aung (1)
Jul 9, 2021

NASA’s Mars Perseverance rover acquired this image using its left Mastcam-Z camera. Mastcam-Z is a pair of cameras located high on the rover’s mast. This is one still frame from a sequence captured by the camera while taking video. This image was acquired on Apr. 22, 2021. Credits: NASA/JPL-Caltech/ASU/MSSS

The idea for NASA’s Mars Ingenuity helicopter began at the Jet Propulsion Laboratory with a team of dedicated engineers who believed in something seemingly impossible. MiMi Aung served as the project manager on the helicopter, which has now achieved nine flights on Mars. In this episode of Gravity Assist, she shares the history of the helicopter project as well as her secrets for leading groups of people to accomplish things no one has ever done before.

Jim Green: We know how to land a rover on Mars. But what does it really take to fly a helicopter on the red planet? It takes Ingenuity.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with MiMi Aung. And Mimi is the lead engineer on the Mars Ingenuity helicopter, developed and managed out of Jet Propulsion Laboratory in Pasadena, California. Welcome, MiMi, to Gravity Assist.

MiMi Aung: Thank you, Jim. It's really great to be here.

Jim Green: So when you were young, what were your childhood dreams?

MiMi Aung: Well, you know, I grew up, you know, different parts of the world. Right. So, I mean, I was born here a while my, you know, in the U.S, while my parents were, you know, getting their PhDs. And then when we went back to Burma, Myanmar, and, you know, I grew up there. My formative years. And then I moved to, we moved to Malaysia, you know, I had further and I had my education was always progressing along there. And then I came back to the U.S. So just being you know, all over the world, it wasn't clear to me if I would ever have a chance, you know, to explore space. I mean, but one thing that always fascinated me wherever you are, which, regardless of what part of the globe you're in, you can always see the sky, the stars, and the fundamental question, you know, of, you know, what's out there? Is there life elsewhere. Are we alone? That's the question that I've always had.

Jim Green: You studied electronic engineering at the University of Illinois in Champaign-Urbana, where you earned a bachelor's and then a master's degree. How did you go from there to Jet Propulsion Laboratory?

MiMi Aung: When time came to look for my first job, and that was exciting, right, you've been in school all your life.

Jim Green: Right. (laughs)

MiMi Aung: And, and one of the professors said, you know, NASA Jet Propulsion Laboratory, you know, they have the Deep Space Network that tracks these tiny little signals with, you know, large antennas and extremely low-noise amplifiers that actually, you know, let you amplify the signals, which after that, you have to process very carefully, you know, to retrieve the signals. And that comment really connected me back, you know, to what I really loved studying, right, really the signal processing algorithms and the communication systems, and then the idea of Deep Space Network and tracking these tiny little signals in deep space. Anyway, that got me to say, “I am going to get an interview with that place.”

Members of NASA's Ingenuity helicopter team in the Space Flight Operations Facility at NASA's Jet Propulsion Laboratory react to data showing that the helicopter completed its first flight on April 19, 2021. Credits: NASA/JPL-Caltech

Mimi Aung: And the University of Illinois hosts, you know, recruiting groups, right, from all the different companies, different agencies, and JPL was there. They had a little star system with, you know, gold and silver, and, you know, I don't know how many colors, but it was all the gold stars I could stick on to get an interview with JPL. And I did. (laughs)

Jim Green: (laughs)

Mimi Aung: And that's how it started. And I can tell you, Jim, the day, I clearly remember that day, it's been now, you know, over 30 years, that interview, but when I walked in on lab, and all the conversations, I remember who I talked to, very clearly, and it was just magic, you know. Once I walked in, and the kinds of work that was being done at NASA JPL and I could see all the different places where I can apply, pursuing, doing things that, you know, you have dreamed of doing until then.

Mimi Aung: Driving down that Oak Grove Drive, right? Like that feeling of, “I'm driving into the Jet Propulsion Laboratory, I can't believe it.” That feeling? It really never went away. I mean, just the other day, right. I mean, now we're, you know, working remotely. But going back on lab, I have the same feeling. And I've had it like, every day that I drive in. And so anyway, it really has been a dream come true. And I've enjoyed it for three decades. 30 years!

Jim Green: Well, you know, the Deep Space Network, as you, as you've already noted, is just tremendous capability for not only NASA, but for the nation. I mean, it is our way of communicating with all our probes. So what were some of the kinds of projects that you did, what did they assign you to do?

MiMi Aung: All right, well, this answer is gonna date me. But (laughs)…

MiMi Aung: This was 1990. When I was arriving, the DSN, the Deep Space Network, was just putting in their first digital receiver. They were replacing the analog receivers with a digital receiver. So I joined the Block-V Receiver group, which is the first digital receiver. And, and by the way, Block-V Receiver is still operational in the field today. So you can imagine that as the signal processing engineer, right, it's just a dream come true.

MiMi Aung: So I was an analyst in the signal processing communications area for the Block-V receiver with, I was in the team. We designed the algorithms, and then when they got implemented into the hardware and the software, and then we you know, after that team implemented it, we did the integration and test, and then followed all the way through deployment into the DSN, you know, across in California, in Madrid, Spain, and Canberra, Australia. And it was just, it was just fantastic to see, get a chance to participate all the way from the algorithms, and then really participate through the implementation all the way to deployment and making a system work.

MiMi Aung: I've been to all the complexes and I, I love the DSN. That was my initial home, so to speak. Yes.

Jim Green: Yeah, well, you've managed so many teams that have done enormous amount of important work for, for the nation and for NASA. What's your secret in building these teams?

MiMi Aung: Well, I think the first secret, I think you have to be truly passionate, passionate about the cause that the team is pursuing, you know, whether in my case, it's been the Mars helicopter or autonomous system capabilities for the future. It's definitely not a, you know, 9 to 5 job. And I really believe in having team members that believe and are as passionate as I am. And really, once you enroll them, so I always say, you know, “I'm enrolling you deep down to your heart,” and people look at me funny, but I think after people who work with me after a while, get what I'm saying. Because then what we do is, I really also respect every person. There is no hierarchy in terms of importance of what you can contribute. And there is no hierarchy on how easily you can also bring the entire system down.

MiMi Aung: I really believe in diversity, the technical diversity, and the technical responsibility. And there is no hierarchy, which means everybody really needs to respect the system, and everybody has to respect everybody else. Otherwise, you know, the kinds of systems we do here at NASA, and you know, and myself personally in JPL, they are not things that are straightforward by any means. And, and so you really have to respect every single discipline. And so I think my secret sauce is: Have passion, respect what everybody's bringing to the table, and then, you know, really expect the excellence, the best of yourself and all the teammates. And I really think you can make, you know, really, really, really big things happen.

Jim Green: Yeah, magic happens when that occurs.

Jim Green: I'd also heard that you worked on the Psyche mission, you know, and that's that fabulous spacecraft going to a really unique asteroid that may be a metal core. So what was your contribution on Psyche?

MiMi Aung: Yeah, Psyche is, you know, fabulous mission. And, you know, in addition to the primary goal, to go to Psyche, right to the asteroid, they are also hosting a new technology, Deep Space Optical Communications, a technology demonstration package. And so, now, they are two different objectives, you know, two different projects, so to speak, that come together on the same flight system. And so my contribution was to join, and to be the accommodation manager on Psyche, to accommodate the Deep Space Optical Communication. And that was a perfect position for me, because, you know, Jim, we were just talking about my fundamental belief in getting new capabilities infused into future missions. And whenever there is a deep space mission, it is the ultimate platform, right, for a technology demonstration opportunity to mature a technology. And so, again, the optical comm getting demonstrated in deep space, for the first time, making this successful, I was definitely motivated.

MiMi Aung: And it really was a fun job.

Jim Green: We're moving into that era where humans will be walking on the surface of the Moon and then on to Mars. We're going to want high resolution video, data, voice, and that requires these kind of communication systems for us to investigate. So that's a great step.

Jim Green: So I was always a big proponent of technology demonstrations. All right? So that gets us to I think the next huge step in your career. How did you get involved in building that helicopter for Mars?

MiMi Aung: (laughs) Oh, yes. That's another major technology infusion activity, very motivated, very driven, you know, for the future. So, yeah, at the time the helicopter concept was born or revived, I was the deputy manager of the autonomous systems division. So I remember, actually, there was a tour of our division by our prior director, you know, Dr. Elachi. And one of the demos we showed was some drones being used to demonstrate autonomous navigation algorithms, OK. This was just in a room with drones. And on the way out, he said to me and René Fradet who was the deputy director of the engineering and science directorate at the time. 

MiMi Aung: And so he turned to René and me, and he says, “Why aren't we doing, you know, things like this at Mars? Why aren’t we flying at Mars?” So, from the division position, we connected Dr. Elachi with Dr. Bob Balram, right, who had done research at JPL on, you know, Mars helicopters in the 90s. And so, Bob and Dr. Elachi and Dr. Jakob van Zyl, who was you know, the associate director of strategy at the time, and they kind of, you know, quietly said “Hmmm, this, it may be worth, you know, investigating.” Well, over that year, Bob's analysis did show that perhaps with the advancement of technologies now, you know, his research was in the 90s. Now, in the 2013 era, technology maybe may have advanced that maybe we can build an autonomous system light enough that we could, perhaps build the Mars helicopter.

MiMi Aung: And then once it started to mature, it looks like it is possible, may be possible, still may be, we started to put more funding into that. And that was about the time I joined from the autonomous systems division deputy manager position to leading the Mars helicopter. So I joined Bob and the team. And then we started growing the team from there. And it was still internal, we first demonstrated that we could lift with a little 1/3 scale vehicle, that was about the time that I joined in 2014. So from there, I was still, you know, keeping my other job as the in the autonomous systems division management position and kind of going part time. And it was an interesting, again, pivot, because it was hard to tell where it was going.

Jim Green: Well, you know, about that time, Charles Elachi, you know, loved that idea, gave me a call, I was the head of Planetary, of course, at NASA Headquarters, and said, “Jim, I want to helicopter on Mars. And, you know, how can we make that happen?” And I said, Charles, well  we’re going to put out a call for instruments on what now is Perseverance. I said,”You must propose it, I can't just tell you to go do it.” All right. And indeed, JPL put together a fabulous proposal. And eventually, as you know, we we said, let's do this. A wonderful tech demo, a wonderful opportunity for us to move forward.

MiMi Aung: We really started with the question of whether it was possible. And so the way we started is, we started with a fairly compact team. And one of the, you know, first thing is to really grasp the concept and map it down.

MiMi Aung: And I remember, I think, one of the first meetings saying, “Look, all of us have the ability to, enabling position to make this happen. But each of us also have the ability to bring this thing down, literally.” And so that was just a principle we all worked on that if we ever made a decision that was great for just our, our own area, but are not aware of what it is, it is so easy to really destroy the entire system. And so that's the fundamental principle that we followed from that day one, I remember that meeting, I said “All of us have to be system engineers, as well as we have to be as the best we can in each of our areas, or else, it just won't work.”

MiMi Aung: And we were also, also jointly so excited and passionate, really, from day one about this chance to fly something in the atmosphere of another planet outside of Earth. And that passion was really deep in all of us. And it goes all the way from not just the technical, you know, technical excellence that came out of each of us. But the personal dedication. I mean, there were a lot of people that made personal career choices.

MiMi Aung: So the job I was talking about the deputy division manager position, I was part time on it, but after a while, it you know, [the] helicopter really grew and you know, need it all, you know, one’s attention. And it was the most uncertain job for you to walk away to the other one. But those are examples. And there are many of us, and so many people, you know, put off their honeymoon for seven months.

Jim Green: Wow.

MiMi Aung: And somebody cancelled a vacation on the spot because there’s tests that needed a few days. And his flight was in a couple of days. And he just said, “Nope, I'm not getting onto that plane to Taiwan, you know, I'll put off the trip.” And it's all driven by this opportunity to add that aerial dimension to space exploration.

Jim Green: Well, as you said, you and your team made it happen. It was as you made these major increments and demonstrated more and more. We were going to keep going. So long as you were successful, you were going to get the green light.

MiMi Aung: This is the beauty of the NASA culture, everybody just chips in, and gives their very best. And there was so many technical challenges that we all overcame, but the reason we did was we thought together, and we solved together.

Jim Green: Well, you know, as head of Planetary, I saw that all the time. You know, it was almost like we were doing miracles, one right after the other, you know, at the centers and the missions we were accomplishing. And it really is all about that team effort, it all about is that vision that everyone gets on that wavelength and then works as hard as they do to make it happen.

Jim Green: When you know, the first flight of Ingenuity took place on April 19. Now, if it wasn't for the pandemic, I would have been there.

MiMi Aung: Yes.
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Gravity Assist: A Dream, a Team, a Chance to Fly on Mars, with MiMi Aung (2)

Teddy Tzanetos, MiMi Aung and Bob Balaram of NASA's Mars Helicopter project observe a flight test. The image was taken on Jan. 18, 2019 as the flight model of the Mars Helicopter was tested in the Space Simulator, a 25-foot-wide (7.62 meter-wide) vacuum chamber at NASA's Jet Propulsion Laboratory in Pasadena, California. Credits: NASA/JPL-Caltech

Jim Green: As you probably know. But what was that moment like? I mean, I saw it from afar. And and I was I was jumping up and down with the best of you. But what, what was it like? How did you feel when it really took off?

MiMi Aung: Oh, it was, it was phenomenal, really, you know, and the thing that I didn't realize until the day is coming up to it, well maybe I realized that it really hits you is you really had to be prepared for every possible outcome. So until that moment, right, you have three or four scenarios, right, ranging from “it didn't work, it didn't start flying and we have to try again” to “it flew but crashed” to “it flew and landed exactly the way you thought it would.” And there is no way of telling where it was going to be.

MiMi Aung: Because we've done all the simulation. We've done all the tests on Earth, and it really, you know, should work, right? We had no doubt. And so, so there was a whole range of emotions that you're preparing for, right? And you have to, you know, just be ready for everything. That's what engineering is, right? You analyze, you design, you test, it's gonna work, but until you go over that threshold of really doing it, you know, you don't know the results.

MiMi Aung: So for me, it was it was really exciting. And they were getting hints we were starting to get about you know, the event reports that were starting to come down and they were looking nominal, right, like, hey, it looks like it started out right. And I think Håvard and Michael were reading what visibility we have and we were starting to smile. But for me the thing that hit it was the altimeter plot. Once I saw the altimeter plot that just shot up to the three-meter altitude and then very quickly coming down. I think that's the point I jumped up, I couldn't can't stay anymore. So yeah, because at that point, you say “Wow, we've nailed it.” You know, we promised NASA right, at least one flight, right. So there was our 100% success flight.

MiMi Aung: And whenever there were difficult moments, what got us going forward was this dream of it flying at Mars, right. And so really, for me, the most important flight. There are beautiful, much more challenging flights going on, as we, you know, that we have proceeded on with, but I think the first flight will be ever, forever, will be the most important flight. It was a dream come true moment, and not just even dreams, like, you know, when you work for a reward, you know, this is like the absolute definition of a reward right, in every dimension.

Jim Green: It was indeed beautiful. I agree. Well, you know, to me, as you moved on to other flights, you also ran into flight number six. And that was pretty exciting. Can you tell us a little bit about what happened?

MiMi Aung: Yes, so flight number six was when we had a very long distance flight, right, and I'm trying to remember, about over 200 meters, you know, kind of flight. And then at the end of the flight, we were making maneuvers, you know, to turn and to take color pictures to construct stereo imaging, and then, in fact, come back a little bit, about 50 meters back and then land. So it's, it's very sophisticated, you know, a large distance, and then almost a little slight U turn, and then to land. Well, at the end of the long the first long leg, right? We took some color image, we took a color image, and just the activity, the increased activity on board triggered a time tagging-issue on the black and white camera, the navigation camera.

MiMi Aung: What happened was because the onboard estimations were off, right, as you know, where we were actually were versus, you know, where what the camera time-tagging, it was telling, it became a rugged flight. And so, the vehicle thought, you know, these errors, because you're going like large errors, and I have to be here, but I'm here and there was a lot of confusion. So, flight control stability margins were stretched, but it's still within, it stayed stable, you know, the vehicle stayed stable, and the vehicle landed, and at the end, it ended up within five meters of the targeted position.

MiMi Aung: It really was quite a stress test. And it was great because, because it all did, you know, work and Ingenuity, again, it landed safely within five meters, which is fantastic performance.

MiMi Aung: We really got a lot of really great data on the performance of our vehicle, so yes.

Jim Green: Yeah, you ran into an anomaly, but indeed, you were able to then overcome that. And, as you say, learn an enormous amount from that. Congratulations, that that was really exciting.

Jim Green: You know, for young ladies who have an interest in science, technology, engineering and mathematics, and they all may be listening, what would your advice be to give them the gravity assist they need to step into your shoes one day?

MiMi Aung: Oh, my advice? Oh, follow your heart. And I know it sounds motherhood, apple pie, you know, but it matters. I think it's important for everyone to really figure out what makes you passionate, like what do you want to make happen for the world? Right? Or for whatever, what do you really want to make happen? And it turns out, each of us have different, you know, callings, you know, for me, it's, you know, first-of-a-kind systems that answers big questions or big causes, okay, so at NASA is first of a kind systems and my passion has been, you know, is there life elsewhere? Are we alone and as an engineer, you know, things that I can do to help make systems you know, that really will help answer the questions. So for all these 30 years, you know, I've been here, that's what's drawn me, okay? So, but for you, you know, all of you out there, right, the next generation, it will be your own quest that draws you, okay?

MiMi Aung: But you really have to find what really draws you. Once you find that, find an intersection of what you can do for that cause and an area that, that you're good in and that you love to do. And I really believe it has to be an intersection of what you love to do, what you're good at, and what is needed in the world that you really believe in. And once you find something like that, go after it, you know, go after it, and don't don't say, “Oh, I'm only this. Or you know, I don't have opportunities.” One step at a time, really, you can get there, if you believe in it, you know, and it comes all the way from talking to people or, you know, searching for more information and starting at even a remote opportunity that you can work your way up to get there. And because you're passionate about it, you will find a way.

MiMi Aung: Don't let anybody talk you out of it. Don't let yourself talk out of it. Don't say I'm not good enough. Or sometimes, and I have to share with you, you know, when I was younger, it's like, “It's just me, it's just me,” right?

MiMi Aung: Don’t let that happen to you. You will find a way, you know towards achieving that. So that's my advice. (laughs)

Jim Green: No, I think that's great advice. I can't agree with you more. Well, MiMi, I always like to ask my guests to tell me what was that event or person place or thing that got them so excited about the being the engineer that they are today. And I call that event a gravity assist? So Mimi, what was your gravity assist?

MiMi Aung: So Jim, I think more of a solar electric propulsion type person.

Jim Green: Little pulses along the way, yes.

MiMi Aung: Pulses all along the way. And I think my first you know, big one, of course, is finding that I really wanted to work in space exploration or space-based systems. And never, you know, knowing… growing up, I didn't know if I would have that opportunity. And then once you know that, that that really coming on driving on lab to JPL, NASA JPL, you know, for the interview. And that was a huge moment for me.

MiMi Aung: And, and really, once I got to talk to the people who were doing space exploration. I think that was a huge maybe there's a gravity assist moment, because to me, it was more like Well, I'm here like I really, it could be as cool as I thought it was going to be and if I think that's where I became mentally committed. I think you need that gravity assistance. So that was one. And then my, you know, this Block-V receiver group, I know I go back to it a lot and but it really was how I got grounded right into how do you turn these algorithms that I was learning in school to a really big system.

MiMi Aung: And that really propelled me into and this is where I owe, you know, a majority [of] that to my first supervisor, you know, Ernie Stone, because he just didn't lead he taught us, all of us in the group, what it took, it takes a whole village, it takes every engineering discipline, you know, all the way, right, from somebody soldering, you know, all the way to, you know, somebody climbing up the antenna to do something to you know, they're all the fancy algorithms or whatever, you know, everybody really had to contribute together. So that was another huge assist, and probably gravity assist, but maybe over seven years. (laughs)

Jim Green: (laughs)

MiMi Aung: And then entering the world of now the spacecraft side, going from the ground side to the spacecraft side. And then the other gravity assist turning moment was really… again, I keep going back into you have to be passionate, you have to love what you do. Once on the spacecraft side, after being there, I just became obsessed with wanting to push the autonomous capability of systems. And so being obsessed with that, and then of course, you know, and that led into everything I do. And then ultimately, helicopter, Mars helicopter is an example of where I actually got to then dip back down into the details to make one of those, you know, future capabilities happen.

MiMi Aung: You know, I literally grew up in NASA JPL, right, walking in as a 23-year-old. And I am, you know, as I move on to take, there's a next big thing that I want to pursue as I move on, you know, like somebody who grows up as you move away from your village to go on to the next, you know, village or whatever. It's, it's, it's, it's a, it's emotional. And I guess I had this fear of, you know, this place that I've loved so much, and all the people I've bonded with. I just hope I won't be forgotten. So the thing I want to say…

Jim Green: I don't see how that's possible.

MiMi Aung: So the only thing is, please don't forget me. I think that's what I want to leave with. So…

Jim Green: No, no, no, no, no, MiMi, you're well placed in history. And I certainly will not forget you.

Jim Green: So MiMi Thanks so much for joining me and discussing your fascinating career.

MiMi Aung: Thank you. And it's been a fantastic conversation. Thank you so much, Jim.

Jim Green: Well join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green, and this is your Gravity Assist.

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Jul 9, 2021
Editor: Gary Daines

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #20 dnia: Kwiecień 23, 2023, 23:00 »
Bliska, a bardzo zagadkowa planeta

Lori Glaze: Well, we have lots of indicators that make us think that yes, Venus once had a lot of water. We have measurements from the Pioneer Venus large probe mission in the 1970s, that had some measurements that made us think that yes, there was an enormous amount of water present in the past. We also know that the, the molecules that got delivered to Earth that would have been a source for water on Earth would have also come to Venus. And there's every indication that Venus started out very similar to Earth with lots of water, that it would have been a water planet in the past. But we just know that somehow over time, that atmosphere heated up, and a lot of that water was lost to space.

Gravity Assist: Onward to Venus, with Lori Glaze (1)
Jul 23, 2021

Lori Glaze, director of planetary science at NASA, described NASA's Mars exploration strategy at a briefing before the InSight spacecraft Mars landing in 2018. Credits: NASA/Bill Ingalls

Venus is so close, and yet so far in terms of our understanding of its history and geology. Early in its history it may have had an ocean just like Earth’s, and volcanoes may be erupting there today. The only way to find out more is to take the latest technology to Venus and take a closer look! NASA is sending two missions to Venus this decade and participating in a European Space Agency mission there, too. Lori Glaze, director of planetary science at NASA, discusses these missions and why she’s so excited about what we’re about to learn.

Jim Green: The bright morning star and evening star turns out to be the planet Venus. What is NASA doing about exploring that next?

Lori Glaze: There's every indication that Venus started out very similar to Earth with lots of water, that it would have been a water planet in the past.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Dr. Lori Glaze. And Lori is the director of Planetary Science at NASA headquarters in Washington, DC. In fact, Lori got this fabulous job after I left to become the chief scientist. Welcome, Lori, to Gravity Assist.

Lori Glaze: Thanks, Jim. Great to be here.

Jim Green: Well, you know, before coming to NASA Headquarters, you were at Goddard Space Flight Center. What did you do there?

Lori Glaze: Oh, gosh, when I was at Goddard, I did a lot of different things. I was a scientist. So I did a lot of science where I did research on volcanoes across the solar system, including volcanoes on Mars; and volcanoes on Venu; and volcanoes on Io, the moon of Jupiter. And so that was my, my main science background. But I also got really interested in developing new mission concepts that could explore the solar system; in particular, exploring Venus.

Jim Green: Well, you know, we've got a lot of missions that have gone to Venus in the past. So we do know a few things about it. Can you tell me why the fascination with this beautiful planet? Where is it in our solar system?

Lori Glaze: So Venus is actually our closest neighbor in the solar system. It's our closest neighbor. And it's actually closer to the Sun than us as well. So Mercury, and then Venus and then Earth. And what's so fascinating about Venus is that both Earth and Venus are about the same size. Venus is a little smaller, but not much. So they have similar gravity. They formed in the same part of the solar system, they probably formed at about the same time. And so we would assume that they were all made up of the same materials, they started in the same place. And you would think that they would have evolved very similarly. But they didn't, they have, somewhere along the way, they took very, very different paths. Earth and Venus went very different directions.

Lori Glaze: Where Earth now has an oxygen rich atmosphere, we have liquid water on the surface, we have an environment that's very comfortable for us as, as humans and for lots of different types of life. On Venus, the atmosphere is almost all carbon dioxide, about 95% carbon dioxide, and there's so much of that carbon dioxide. It's such a thick atmosphere that it has a really strong greenhouse effect, meaning that the solar radiance comes into the atmosphere, but the thermal energy can't escape and it is incredibly hot at the surface.

Lori Glaze: So what we really want to understand is, as we're discovering thousands of new exoplanets, it's hard for us to tell when we look at them, are they going to be exo-Earth's or exo-Venus's? And so the more we understand about Venus, the more we'll be able to understand exactly what makes an Earth? What makes a planet become Earth-like or makes a planet become Venus-like?

Jim Green: Well, you know, Venus's atmosphere is so thick as you say, 90 times our atmosphere, that it almost acts like a fluid on the planet. And so the temperature and pressure is the pretty much the same anywhere you go on the day side and the night side. Pretty remarkable.

Lori Glaze: It is remarkable. I'll tell you another fun fact about Venus. You're absolutely right that the temperature doesn't change with day to night, it changes from equator to pole, but Venus actually also rotates backwards from Earth, and it rotates on its axis so slowly that a day on Venus is longer than its year, meaning that it takes longer to rotate on its axis than it takes for it to make the entire trip all the way around the Sun. It's a weird place, but definitely fascinating.

DAVINCI+ will send a meter-diameter probe to brave the high temperatures and pressures near Venus’ surface to explore the atmosphere from above the clouds to near the surface of a terrain that may have been a past a continent.

This is an artist’s concept of DAVINCI+, a mission that will send a m probe to brave the high temperatures and pressures near Venus’ surface. During its final kilometers of free-fall descent, the probe will capture spectacular images and chemistry measurements of the deepest atmosphere on Venus for the first time. Credits: NASA GSFC visualization by CI Labs Michael Lentz and others

Jim Green: (laughs) But you love it.

Lori Glaze: I do.

Jim Green: The only blue planet on our solar system today is Earth. And there's been a lot of discovery at Mars, indicating that Mars was a blue planet. Also, early on in its history. What about Venus?

Lori Glaze: Well, we have lots of indicators that make us think that yes, Venus once had a lot of water. We have measurements from the Pioneer Venus large probe mission in the 1970s, that had some measurements that made us think that yes, there was an enormous amount of water present in the past. We also know that the, the molecules that got delivered to Earth that would have been a source for water on Earth would have also come to Venus. And there's every indication that Venus started out very similar to Earth with lots of water, that it would have been a water planet in the past. But we just know that somehow over time, that atmosphere heated up, and a lot of that water was lost to space.

Jim Green: Well, you recently announced two new missions, what we call Discovery missions, and they're going to Venus, what are they all about? Tell us what are they gonna do?

Lori Glaze: I am really excited about both of these missions, two missions to Venus, one of them called VERITAS and the other one called DAVINCI.

Lori Glaze: And these two missions are really highly complementary. They're both interested in helping us answer questions about how a rocky planet with an atmosphere, how that those planets form and how they evolve over time. But they go about the different observations in very, very different ways to help us answer some of those questions.

Lori Glaze: So the VERITAS mission is an orbiter, it's going to go into orbit around Venus, and it's going to carry with it an amazing synthetic aperture radar system that actually has two antennas and allows it to, in one orbit, collect topography and understand the the topography of the surface of Venus understand the elevations of the ground below. That's a really challenging thing to do on Venus, because there's such a thick atmosphere that you can't see to the surface in the normal visible wavelengths. You have to use a radar system really to see through and measure this topography. Do they're going to get the highest resolution topography we've ever seen for Venus globally, so that'll be amazing.

Lori Glaze: They also are going to carry an infrared instrument that does allow them to kind of poke through and see through the clouds at certain wavelengths and measure how the surface reflects in those wavelengths, and how it emits energy and those wavelengths. And that'll help tell us more about the crust and its properties.

Jim Green: In addition to that, isn't it going to be looking for hotspots, perhaps volcanoes?

Lori Glaze: So VERITAS will be looking for potential hotspot. That infrared detector will be able to look for things that may be emitting energy at higher temperatures. And so perhaps there may be some indication of active volcanoes on Venus. An earlier instrument flown by European Space Agency thought that maybe they saw hints of that in these infrared wavelengths. And so we'll see with VERITAS, you know, whether we can see similar signals on Venus.

Lori Glaze: Many of us are really intrigued by the idea that Venus could have active volcanoes today. And Venus being almost the same size as Earth, the interior should still be hot. And one of the main ways Earth loses its heat is through volcanoes. And so it seems like Venus should still have active volcanoes. We've actually seen some evidence of that, possibly some measurements, where we've seen sulfur dioxide, big spikes, where there's a sudden increase in the amount of sulfur dioxide that we can see at the cloud tops of Venus. And we know on Earth, that volcanoes put out a lot of sulfur dioxide. So some people have suggested maybe the sulfur dioxide we see on Venus might be from volcanoes. We've also seen in infrared images, looking at the emissivity of the surface spots, that look like they may be warmer, and that may be active lava flows. So we don't really have a smoking gun yet. But there's, there's a lot of good indicators. And certainly, it seems like a place where volcanoes should still be active.

Jim Green: The other discovery mission is DAVINCI+. So once again, a fabulous mission. What is it supposed to do?

Lori Glaze: So the DAVINCI mission is really a cool mission to fly a small probe, which is about a meter across, a big sphere. And that mission is going to send that probe down into the Venus atmosphere to measure the gases in the atmosphere. And there's going to make the types of measurements that you can't make from space, the only way you can make these measurements is to actually suck in the gas and sniff it and, and measure directly the chemicals that are contained in the gas.

Lori Glaze: So it's going to measure gases like helium, neon, argon, krypton, xenon, all of these gases that are called noble gases because they don't like to play nice with the other gases, they don't like to combine with anything. And so those gases are really good indicators, kind of like little molecular fossils in the Venus atmosphere, to let us see back into what Venus's atmosphere was like billions of years ago, and how it may have changed over time.

Lori Glaze: So very cool measurements, also going to measure water vapor in the atmosphere, and it's going to measure two different kinds of water, the heavy water which is deuterium and the lighter water, which is hydrogen. And by measuring those two, it'll help us understand the story of water in Venus's past, because we think Venus had a lot more water way long ago and billions of years ago that has all escaped, and that deuterium and hydrogen, the hydrogen escapes more easily, we'll be able to measure that ratio, and that will give us a sense of how much of that that water has actually been lost.

Lori Glaze: And then finally, it's also going to measure the trace gas chemistry, all of the chemicals like sulfur dioxide, carbonyl sulfide, carbon monoxide in the lowest part of the atmosphere, it's never been measured before. And then I guess I should say one more thing it's going to do: Its carrying a camera, which is always awesome, because as it comes down at the very end of its descent, it's going to take pictures that we can see for the first time what some of the really rugged terrain on Venus looks like up close. So that'll be really cool as well.

Jim Green: Is it expected to survive all the way down to the surface?

Lori Glaze: Yeah, the DAVINCI probe is expected to survive all the way to the surface. Now that is a hard thing just by itself. It takes about an hour for that probe to descend all the way through the atmosphere. It's not like Mars where you have seven minutes of terror. It's more like an hour of, of extreme nervousness as it comes down. And the atmosphere of Venus of course is very, very hot. Very, very hot near the surface —  850, 900 degrees Fahrenheit — you've got incredible pressures, essentially, it's about 100 times more atmospheric pressure than on Earth. And so it's like if you were half a mile underwater, so really not, not a comfortable place for a spacecraft. But it should survive all the way to the surface. It doesn't have to survive after landing. But, you know, we'll see if perhaps it's able to take one more picture once it once it lands.

Jim Green: So let me get this straight. We're going to drop a probe off at Venus. It’s going to fly through sulfuric acid. It's going to encounter enormous temperatures hot enough to melt lead and crushing depths. How do you build such a probe?

Lori Glaze: It's not an easy thing. So I'll tell you that the, the probe itself is actually made of titanium. And the titanium is very resistant to the sulfuric acid. It's also, structurally, it's one of the strongest, but lightest metals that we can use. So we're we really want to keep our mass down as low as possible. So that titanium lets us be really strong, you know, resist the pressure of that really dense atmosphere, but also be lightweight.

Lori Glaze: Now, we have to stay cool and that is really hard. And so I will tell you that what we're going to do with DAVINCI is it is going to carry something we call a phase change material. So think about ice cubes, right? That as the ice melts, it, it keeps your water at the same temperature doesn't get warmer or, or colder, right until all of the ice is melted. On DAVINCI, they're not going to carry ice cubes, of course, they carry some type of a salt material or a wax material and, you know, depending on what they've chosen. And that as it melts, helps keep the inside of that probe all at the same cool temperature, cool relative to the outside temperature, so that all the electronics and the instruments can operate at the same temperatures that they are comfortable operating at.

Lori Glaze: You know, that'll melt pretty fast. And it, you've, you've only got an hour to get through. So they just have to carry enough to survive that hour. And I'll tell you another fun fact about Venus, the world record for surviving on the surface of Venus is two hours by one of the Venera landers that was launched by the Soviet Union. So, you know, two hours is the is the best we've done so far, surviving in that high temperature environment.

Jim Green: Indeed, Venus is so hot, we don't expect any liquid water on its surface. So as it has evaporated the water, there's been chemical interactions in the upper atmosphere and it creates sulfuric acid. So is DAVINCI+ able to punch through the level of sulfuric acid in the clouds of Venus?

Lori Glaze: It will punch through the, the clouds. It'll come right down through there. And that's exactly where it'll start making its measurements is when it's in the clouds, in those sulfuric acid clouds. And I will just say one note, there was a mission that went to Venus, back in the 1970s, called Pioneer Venus. And they actually when they tried to measure the atmosphere, they actually sucked in one of those sulfuric acid droplets, and it clogged up their tubes. And so they weren't able to make all the rest of the measurements that they wanted to make. So DAVINCI has lots of plans for not letting that happen to make sure that they are able to make all the gas measurements they want to make all the way down to the surface.
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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #21 dnia: Kwiecień 23, 2023, 23:00 »
Gravity Assist: Onward to Venus, with Lori Glaze (2)

This artist’s concept shows the VERITAS spacecraft, which will use its radar to produce high-resolution maps of the topographic and geologic features on Venus. Credits: NASA/JPL-Caltech

Jim Green: Well, you know, Venus doesn't have a magnetic field and the solar wind continues to strip its atmosphere. But yet it seems to have such a thick atmosphere. How is that possible?

Lori Glaze: That's always a great question because we think a lot about you know, that what we know about the Mars atmosphere, and we know that Mars has lost so much of its atmosphere. And a lot of times that is explained by the fact that Mars doesn't have a magnetic field. And so it’s unable to protect itself from the solar wind. And then you go to the Venus case, and you say, “but how is that true at Venus because Venus also has no magnetic field to protect itself from the solar wind?”

Lori Glaze: But there are some other factors that are at play here. One is that Venus, of course, has much higher gravity than Mars does. And so losing your atmosphere from the solar wind is, is partly a balance between the gravitational pole that's holding the atmosphere in and then that, that stripping from, from the solar wind, and there may also be other processes in play. We're actually still trying to better understand how exactly the Venus atmosphere is lost.

Jim Green: Now in addition to our two discovery missions going to Venus, European Space Agency also announced their mission to Venus. Is NASA involved in that too?

Lori Glaze: We are absolutely involved in that mission. So the European Space Agency, they also selected a Venus mission. It's called EnVision, and NASA is really proud to be participating with ESA on that mission. We're actually going to be contributing a synthetic aperture radar. It's similar, but actually quite different, from the radar that's going to fly on VERITAS. And this radar system is going to be focused on taking very high spatial resolution images in targeted locations on Venus. So that will be awesome.

Lori Glaze: It also is going to carry a ground penetrating radar, and a spectrometer that looks across several different wavelength regions. And so that will really help us characterize the atmosphere, and also, in some cases, be able to penetrate down to the surface. So these missions are all really complementary and between VERITAS, DAVINCI and EnVision, it's going to be a great resurgence of Venus science. And we're looking forward to a coordinated effort across all of our international science community.

Jim Green: Well, what's the order of launch between these three missions?

Lori Glaze: Right now, the scheduled plan is that VERITAS would be the first one to launch. At around the 2028, I believe is the, the schedule right now and then followed shortly by DAVINCI in 2029. Possibly 2030. But very close there together. And then the EnVision mission would follow after those two. Its baseline is to launch in 2032. But I know ESA is actually looking at trying to see if there's a way to launch a little earlier. So they're going to launch very close to each other. This will be a really synergistic exploration of Venus at the end of the 2020s.

Jim Green: Right, and so with VERITAS, first getting that broad picture, enabling then EnVision to really hone in on just the right places. That will be spectacular.

Lori Glaze: Absolutely, that's exactly the way this should happen. That you know, VERITAS is going to do the global mapping, EnVision’s going to do the high-resolution imaging. And then you know, DAVINCI is going to add on top of this incredible in situ chemistry measurements.

Jim Green: Wow, can’t wait.

Jim Green: So you're the director of planetary science at NASA. And I would say you have the job to be the top advocate in the federal government for planetary missions. Can you give us an overview of what your job is like?

Lori Glaze: Oh, my gosh, yeah. And you're right. The main purpose of this job or the main responsibility is to be that advocate, and to really speak to the amazing science that we're doing. And the planetary science portfolio right now is just chock full of incredible science missions. Last time, I counted, I think we have 39 missions in our portfolio that are including our participation on partner-led missions going to Mercury, we got now missions going to Venus, we have a whole slew of missions going to the Moon. We've got a bunch of things at Mars, we've got missions at Jupiter, we're going to have a new mission going to Europa, the moon of Jupiter.

Lori Glaze: We've got missions all the way out into the Kuiper Belt. So it's incredible science, you know, my day-to-day job is I get to learn about the incredible science going on on all of those missions. I get to talk with the scientists that are, you know, developing those missions, and then talk to the scientists, of course that are then using the data and making the fantastic new discoveries. It's, it's an amazing job, as you well know.

Jim Green: I do, I do, but I have to tell you, I do appreciate how hard it is. It’s, to me, it's the toughest job I ever had. I greatly admire you and all the efforts that you're doing to make this work and it's just really spectacular. Well, what's the next mission you're going to launch?

Lori Glaze: So the next mission that we're going to launch is called Lucy. And the Lucy mission is going to launch in October of this year. And Lucy is a really interesting mission that's going to go study these unusual asteroids that are trapped in Jupiter's orbit. These are unusual in their location, and also in the unique ability of this one mission, one spacecraft to actually visit seven different asteroids that are out there, a great alignment of orbital dynamics, and the physics of our solar system that allows this spacecraft to go visit multiple asteroids.

Lori Glaze: And these are amazing remnants of our early solar system and by visiting lots of different asteroids will help tell us that, that early story of how that, the, the solar system formed and where the larger planets migrated during that early formation time. So it'll be a fantastic and exciting mission.

Jim Green: Well, Lori, I always like to ask my guests to tell me that event or person place or thing that got them so excited about being the scientists they are today. I call that event a gravity assist. So Lori, what was your gravity assist?

Lori Glaze: I would say that my gravity assist was an event that happened in May, actually on May 18, 1980, which was the day that Mount St. Helens erupted in, in Washington State. And at that time, I was in high school. And I was living in Bellevue, Washington just up, up the highway from, from where Mount St. Helens erupted. And there was just something about that whole time and the, the leading up to the eruption, when there was a lot of discussion about what was happening at the volcano that I just found absolutely fascinating.

Lori Glaze: And I didn't directly go into studying volcanoes when I went to college. But I got my bachelor's in physics. And I had an opportunity when I did my masters to apply my physics background to studying volcanoes and understanding how lava flows move and how the ash columns rise up into the atmosphere.

Lori Glaze: And I really attribute that event back at that time when I was in high school to what really got me excited about science and got me super excited about volcanoes, and then ultimately led to my real fascination with planetary science.

Jim Green: Well, Lori, thanks so much for joining me and discussing the fantastic things that you do to make NASA's planetary missions happen.

Lori Glaze: Thank you.

Jim Green: Well join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green, and this is your Gravity Assist.

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #22 dnia: Maj 07, 2023, 08:55 »
O znaczeniu NBS (Neutral Buoyancy Simulator) w operacjach kosmicznych.
Felicia Ragucci: So the NBS was used to practice the procedures for deploying, like the protective solar sail and how to save those Space Station. And they were, there were engineers actually doing those procedures in the tank at the same time as the astronauts, we're doing them in space. So that's one, one huge accomplishment of the NBS. And another huge thing is the design and the development of the Hubble Space Telescope, which is amazing because the Hubble Space Telescope is something that many so many people know about. And it's one of the most productive scientific instruments that NASA or anyone has ever created. And this telescope itself was designed and then developed using the NBS. So we were able to make a serviceable telescope by working with hardware under the water in a weightless environment.

Gravity Assist: Diving Into NASA History, with NASA Intern Felicia Ragucci (1)
Jul 30, 2021

On April 1, 1983, divers and astronauts at NASA's Marshall Space Flight Center in Huntsville, Alabama, prepared for the first satellite repair mission in space. Before the repair, the crew of Space Shuttle Challenger mission STS-41-C spent months at the Neutral Buoyancy Simulator, an underwater training facility that is now a historic landmark. Pictured at the top of this image is Jim Green, who is now NASA’s Chief Scientist and host of Gravity Assist. Credits: NASA

In honor of National Intern Day, Gravity Assist features Felicia Ragucci, an undergraduate at Dartmouth College who recently completed an internship with NASA’s History Office and the Office of the Chief Scientist. During her time at NASA, Felicia researched the history of the Neutral Buoyancy Simulator, an underwater training facility where astronauts practiced satellite repairs and other activities. Felicia explains how she researched the history of this place during her internship.

Jim Green: NASA loves interns, and we employ hundreds of them across all the activities that we do, including the history of NASA.

Felicia Ragucci: One of the big questions that was guiding my project is:

Felicia Ragucci How do we practice what we do in human space exploration?

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Felicia Ragucci. And she is an undergraduate student at Dartmouth College. She recently completed an internship here at NASA in the History Office, and also working with the Office of Chief Scientist. NASA has always had tremendous interns, both during the summer, but also during other times of the year. They perform very important work for NASA.

Jim Green: Welcome, Felicia, to Gravity Assist.

Felicia Ragucci: Thanks, Jim. Great to be here.

Jim Green: So what actually did you do to find out that NASA needed interns, particularly in the history department?

Felicia Ragucci: So I interned during the pandemic. And it was kind of during a time when I had just finished taking classes. And then I was going to take my next term of school off. And so I was looking for an opportunity to do an internship or some other experience. And then my dad, one day, told me that NASA was looking for interns, and he saw something about it online, or in an email or something. And I was like, Oh, that's amazing, because, you know, he knows that I love science and love space. So I looked at the application and saw that it was due. This was on a Friday, and it was due on a Monday. And I was so I was like, “Oh no, how am I gonna get this application together?” But I was able to get all my parts done. And a really wonderful professor of mine was able to send in a recommendation just in time, like one hour before the application was due.

Jim Green: Your internship project was to research a historic facility at the Marshall Space Flight Center called the Neutral Buoyancy Simulator. We also call that the NBS. Now the NBS is where astronauts train on how to perform outside work in space, but they do it here on Earth in a water tank, and I was personally a safety diver for many years there.

Jim Green: Well, how would you describe the Neutral Buoyancy Simulator?

Felicia Ragucci: So the Neutral Buoyancy Simulator, it's really cool. I wish I could see it in person. And hopefully I can one day, but since we were remote during the pandemic, I haven't seen it yet. But basically, it is a huge water tank. It's 43 feet deep. And I think 75 feet across, holds like 1.3 million gallons of water. And so the whole idea of this facility is to simulate weightlessness. And so the way that you do that is by achieving a state of neutral buoyancy. And I'm no physics major or anything. But neutral buoyancy is basically when an object is neither going to sink in the water or float in the water. So it's kind of just going to hover there. And you do that by using a combination of weights and flotation devices.

Felicia Ragucci: And you can kind of wade out a suited subject who's wearing a pressure suit, you can use little what lead weights, weigh them out till they're neutrally buoyant, and then they're just kind of hovering there in the water. So effectively, you're using the tank to simulate weightlessness in space. And of course, it is a simulation. So it's not perfect. There are things like water drag, which you'll find in the tank, which won't be in space. But it's a really good simulation for how to work with objects and how to move things, heavy structures around in a zero-gravity environment here on Earth.

Jim Green: Why was the NBS so important to NASA?

Felicia Ragucci: NBS was really important to NASA because it played a role in so many critical missions that NASA has done over the years. And I didn't even know this. So it's really amazing to kind of dig into this history and realize that the Neutral Buoyancy Simulator played a role in so many critical missions, including, I mean, one of the first things did is it played a role in saving Skylab, which was the first space station.

Felicia Ragucci: So the NBS was used to practice the procedures for deploying, like the protective solar sail and how to save those Space Station. And they were, there were engineers actually doing those procedures in the tank at the same time as the astronauts, we're doing them in space. So that's one, one huge accomplishment of the NBS. And another huge thing is the design and the development of the Hubble Space Telescope, which is amazing because the Hubble Space Telescope is something that many so many people know about. And it's one of the most productive scientific instruments that NASA or anyone has ever created. And this telescope itself was designed and then developed using the NBS. So we were able to make a serviceable telescope by working with hardware under the water in a weightless environment.

Felicia Ragucci: And that way, we were able to place handrails and foot rails on the telescope in a way that allowed astronauts to go service the telescope and which is why, you know, we serviced it so that it's still functional today and still producing data.

Jim Green: So as you gathered information about the history of the tank, you interviewed all kinds of people. What were some of the memorable stories that you ran across in your research?

Felicia Ragucci: Yeah, so the conducting oral history interviews was probably my favorite part of this history research project, because it was really fun to be able to talk to so many different people who were involved with the tank, and just really fun to talk to NASA people in general, because I think that this is definitely, yeah, they are, in general, very passionate, and I'm very eager to talk to students and people about their work.

Felicia Ragucci: So for the researching the NBS, I interviewed kind of four different categories of people. The first was engineers, also astronauts, and then divers who worked in the tank, the test conductors and other test personnel who kind of worked at the facility itself full time. So those are the four groups of people that I interviewed. And it was really, really fun to talk to engineers about the tank, because really, at its heart, the neutral buoyancy simulator was a design and development facility. So it was used for concept testing, concept development and creation. So you know, engineers would get in there, get into the pressure suit, have an idea, you know, put up, put in some hardware, some mock ups and try something out. And that's how they would really go about engineering the structures that we find in space today.

Felicia Ragucci: I also got to speak with one astronaut, and that was George D. Nelson, who flew on the Solar Maximum repair mission. And that was a really, really fun conversation. I got to talk with him about the tank and he was telling me about his close friendship with Story Musgrave and how he passed on, kind of, all the responsibilities for taking care of the suit to George, and so how, you know, he was in charge of that as when he was in the astronaut office, and also, you know, in his dives in the NBS, and I also got to talk to him about the Solar Maximum mission and preparing for that in the tank.

Felicia Ragucci: And kind of the, the amazing things that they were able to do with the Manned Maneuvering Unit and how they demonstrated the success of that in space. And they kind of they also had an underwater mock-up of the MMU that they used in the NBS. So that really shows how, you know, side by side, you have the space, you know, doing whatever you're doing in space, and they were able to simulate it really effectively in the water at the NPS.

Jim Green: I should mention the Solar Maximum Mission was a satellite that went awry, and it had the capability of being repaired. And indeed, that mission was spectacular, grabbing this absolutely enormous satellite, and getting it in into the shuttle bay.

Jim Green: Well, now that you know all about the history of the tank, and all the positions that the divers did, and the suited subjects, if you were going to participate in any of the NBS dives, what role would you be and what would the dive be?

Felicia Ragucci: Oh, that's a really fun question. Oh, let me think I think. Hmm, well, if I were to go in the NBS, I think that I don't know if I want to be the suited subject just because that seems like it's a very high pressure roll, and also a bit claustrophobic. So I think of being in the pressure suit might be a little difficult for me, even though it would be really fun. So I think that I would want to be there's a whole network of divers that were really critical to all of the NBS dives. You know, you had safety divers, water safety divers, photo divers, utility divers who were setting up the hardware in the mock ups.

Felicia Ragucci: So I might want to be a photo diver and you know, holding one of these underwater cameras, and videotaping the whole test from start to finish, which they did, because that was the data that each test produced. And so you get this whole video of the test. And you'd be able to extract from that, you know, the important the important knowledge about the spacewalk and about the equipment that they were engineering. So I think being a photo diver would be really fun. And then I'd be able to see, you know, the test from start to finish.

Felicia Ragucci: Jim, I know that you yourself, were a diver in the tank. So can you tell us a little bit about that?

Jim Green: Yeah, I had wonderful memories, many wonderful dives between 1980 and 1985. I did about 150 dives in the neutral buoyancy tank. But my position was as safety diver. So I was responsible for the life of the person in the suit, whether it was an engineer or an astronaut. And indeed, I had a wonderful opportunity to wade them out, I could do that rather quickly.

Jim Green: In three minutes, I could get them neutrally buoyant, put them in any position, let them go, and they would stay there, they wouldn't rise or fall or their roll over on their back, completely neutral, and then take them down to their station where they needed to do their work.

Jim Green: And then watch them as they as they did their work. And as they got into more complicated dives, really ensure that they were always safe and always ready for, for me to step in and, and help them any way necessary to make their job successful. So those dives were great. And I certainly enjoyed that time. And unfortunately, I had to leave in 1985 and go to my next job, which was at Goddard Space Flight Center.

Felicia Ragucci: Yeah, definitely all the divers and people that I talked to always say that they have great memories about diving in the tank. So it seems to be a very fondly remembered thing by lots of folks at NASA.

Jim Green: Well, it really is, when you think about it, you're watching the development or the procedures they're going to use in space, where they're really trying to make something happen, where it doesn't always work, right, where they have to figure out what the next steps are. And it's like being there, it's like being you know, in a suit, watching them, supervising them, in terms of making something happen, like repairing a satellite. And so this really connects all the divers with the human exploration in space.

Jim Green: You know, and they know the essential part of what they do in the tank is fundamental process of getting these people ready to repair or build structures, and make really something important happen in space. And that's been going on since the late 60s. And it's just been tremendously successful. This is one of the reasons why human exploration has done what it's done. And we're in space. For the last 20 years, we've had somebody in space on the International Space Station, which we built. And many of those operations were practiced in the tank.

Felicia Ragucci: Yep. And that couldn't have been done without all the divers and all the people who volunteered. So they definitely played an incredible, incredible role.

Jim Green: Well, in addition to the interviews, you had an opportunity to look over a variety of material. What was the most important material that you uncovered in the history of the NBS?

Felicia Ragucci: Yeah, so for the material that I worked with, it spanned you know, written papers and reports that were written about the NBS. Also a lot of photographic evidence. So there were tons and tons of pictures of the of the all the dives that happened in the NBS and so there's an online archive of those. So I've worked with those photos, as well. is these photos stored at the at Marshall Space Flight Center. But I think one of the most important sources that I worked with was this newsletter, this archived, archived issues of a newsletter that was weekly newsletter that was published at Marshall called the Marshall star. And so we had archived issues of that newsletter from 1968, all the way to 1997, which could span the entire lifetime of the tank.
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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #23 dnia: Maj 07, 2023, 08:56 »
Gravity Assist: Diving Into NASA History, with NASA Intern Felicia Ragucci (2)

Felicia Ragucci recently completed an internship at NASA Headquarters, where she researched the Neutral Buoyancy Simulator. Credits: John J. Cho

Jim Green: And so using that archive of these newsletter issues, I was able to go through and kind of really extract a pretty comprehensive history of the tank, and the who was there, what test they were doing, when it was happening, and any other important news about the tank. And using that information from that archive, I created a 60 page timeline, which kind of covered like, all the basics about the tank and what happened at it. And then from there, we were able to use that to kind of cross reference other sources, figure out dates and times. And people who came to the tank so that that source was was really invaluable to my project.

Jim Green: Well, as you say, this was the first tank that NASA had starting in the late 60s. But as you also mentioned, it was no longer in use after 1997. What happened to it?

Felicia Ragucci: Yeah, so the story of the decommission of the tank, I think, gets a little tricky. So you have the tank at Marshall, which is the neutral buoyancy simulator, the NBS, which is really being used for engineering design and development. But then you also have simultaneously there is a series of tanks, Johnson as well. One was like the weightless environment training facility, then now today, it is the NBL. So the Neutral Buoyancy Lab, which is much larger than the NBS. And so that's kind of the tank that's been in use since the NBS got decommissioned in 1997.

Felicia Ragucci: And that tank is really used more for astronaut training. So a lot of the people I talked to who worked and dove in the NBS, thought it was really unfortunate that the tank was decommissioned, because it really was playing a different role, as opposed to the NBL at Johnson. So it really was at Marshall about engineering, design, development and concept creation. And that type of work is really important to conduct when we're figuring out how to do new things in space and pioneering new missions.

Jim Green: Well, how do you think the history of the NBS really relates to the history of NASA as a whole?

Felicia Ragucci: Yeah, so the history of the NBS, I think, I think it's really important, because kind of one of the big questions that was guiding my project is kind of a simple question. But you when you start to think about it, it's really important. And that question is, how do we practice what we do in human space exploration? That's kind of what NASA is all about. And what the agency is all about is putting humans in space and exploring space in different ways using technology, and engineering and science. And so the tank really encapsulates that idea. And it's all about practicing for that human space exploration, creating new missions, creating new concepts, and testing them out to make sure that, that when we send people and astronauts into space, that they're going to be safe, that they have procedures, and they have the tools necessary to do what they need to do safely. So I think that the NBS is really, really captures NASA's mission.

Jim Green: You know, in terms of doing all this research and accumulating all this fantastic information. What do you think the next step should be to preserve the concepts of the neutral buoyancy tank that was done at Marshall?

Felicia Ragucci: Yeah, so the neutral buoyancy tank, I believe that the facility itself, I mean, it's been decommissioned since 1997. And I believe that the facility is going to be tore down or destroyed, unfortunately, so but I think even without the physical facility itself, there are definitely ways to preserve the knowledge that was gained from it.

Felicia Ragucci: The main data that was collected from the NBS was these videotapes of all these different tests. And then there the various offices that worked in conjunction with the tank and kind of kept all that data and have the marshal so I think that, that that data and all the pictures and the photos and the videos from the tank should definitely be preserved. And especially since neutral buoyancy isn't a dead concept, it's still being done. It's just being done at Johnson now and also at various other space agencies. So neutral buoyancy is really widely used. And so definitely the data and the lessons that we learned should be kept.

Felicia Ragucci: And the other thing too is this came up in one of the interviews that I had with an engineer, but he was talking about technology transfer and how you kind of transfer technology and science to different people. And he said that the way to do that is not to disseminate the technology, but to disseminate the people who worked with it. So I think that the NBS was really great, because it brought so many people together from across NASA, they were, you know, all these all the divers who worked at the tank were volunteers from the center.

Felicia Ragucci: So they thought they had different day jobs, and then they would all come together and dive in the tank so that they would able to, they would be able to meet new people and work on different missions. And they take those lessons with them. So I think that's, that's another key concept too.

Jim Green: Well, I think you'll be happy to learn that you've accumulated so much great information, that indeed, we've started the process of getting a major historian to write up the history based on the material that you put together. And that historian is Roger Launius, who is well known throughout all of NASA, and in the history of space. So congratulations on all that very hard work that you did, it's going to really pay off into, I think, a really great book about the neutral buoyancy simulator.

Felicia Ragucci: Well, thanks. Yeah, it's great to hear, and thanks for all the support that I had during the internship. And I think it's great that it's going to be put into an E book. And you know, hopefully, then it's really accessible to so many people, and they can learn about the history of the tank, which makes all the missions of so many of the missions that we know about possible.

Jim Green: So Felicia, how does your internship relate to what you're going to be doing next?

Felicia Ragucci: That is a wonderful question. My internship came at a really a really interesting time, I guess during the pandemic. I was really, really feel fortunate to have had such a wonderful opportunity and so during my internship was over a period of months when I took up some extra time from school. So I'm currently an undergraduate right now, and I have about six terms of schooling left before I graduate. So I definitely do not know exactly what I want to do still, after I graduate, but I think it will be something that combines Humanities and Sciences in some way.

Felicia Ragucci: And so that's why I really enjoyed this internship experience where, you know, my position was working with both the Office of the Chief Scientist and also the history office. So, you know, it's really been great to have more and more experiences as I get older, that show me that those two things are intertwined. And it's not sciences are separate from humanities, but the two things are really intertwined and depend on one another.

Felicia Ragucci: And I think this podcast and what you do, Jim is a great example of that, because you're doing, you know, science communication, and in telling the public about the science and everything that goes on at NASA, which I think is really important. So science, communication is definitely a field that I would consider, along with other things like medicine, or other things like that. So we will see, but I think this internship has really taught me a lot and helped me develop skills, both in sciences and humanities that I'll use in the future.

Jim Green: Well, Felicia, I always like to ask my guests to tell me what was that event person place or thing that got them so excited that they ended up working at NASA? I call that event a gravity assist. So Felicia, what was your gravity assist?

Felicia Ragucci: So I was thinking about this question and trying to think back to back to my past and younger days and think about something that got me interested in science and in space exploration. And one memory that has always stuck with me is watching. It was a special on Nova, I think it was the Fabric of the Cosmos with Brian Greene, the physicist, and it was like a four part special or something like that. That was on Nova and, and I remember watching that, and just being so fascinated, because I was pretty young.

Felicia Ragucci: And he was talking about, you know, quantum physics and all these sorts of crazy things that happened in that world. So I think that really could capture anyone's imagination. And it definitely did mine and, and I would also credit my dad too, because he's a doctor. So he's a scientist. And he has, you know, he's been a really great inspiration and just seeing him work in his his, like, seeing his example has always gotten me interested in science and curious about the world around me. So yeah, that's my gravity assist.

Jim Green: Okay, sounds great. Well, Felicia, thanks so much for joining me in discussing your fantastic work supporting NASA.

Felicia Ragucci: Thanks for having me.

Jim Green: Well, join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green, and this is your Gravity Assist.

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Jul 30, 2021
Editor: Gary Daines

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #24 dnia: Maj 21, 2023, 07:24 »
O symulacji kosmicznych środowisk fizycznych w laboratorium
Ethan Elliott: So it's a self-contained lab that includes all the seven lasers, all the electronics, and the ultra-high vacuum chamber needed to cool atoms to under a billionth of a degree above absolute zero. It was installed on the interior of the ISS in June of 2018. So it's been operating for about three years. It's created the first Bose-Einstein condensate in orbit, and demonstrated the first atom interferometer in orbit.

Gravity Assist: Freaky Physics on the Space Station, with Ethan Elliott (1)
Aug 6, 2021

The Cold Atom Laboratory (CAL) is a science experiment on the International Space Station that creates an environment 10 billion times colder than the vacuum of space. Credits: NASA/iGoal Animation

The laws of physics get very, very weird in the realm of particles too small for the eye to see. Aboard the International Space Station, an experiment called the Cold Atom Laboratory (CAL) is exploring how the universe works on a fundamental level by cooling atoms down to a billionth of a degree above the coldest temperature possible, absolute zero. By using special lasers and magnetic fields, CAL is making unusual structures called Bose-Einstein condensates almost every day. Ethan Elliott of NASA’s Jet Propulsion Laboratory talks about the exciting possibilities that this experiment offers for the future of physics.

Jim Green: Space is cold, really cold. What happens to the very tiny world of atoms when they are so far away from any sun?

Ethan Elliott: 10 billion times colder than the core of your body is now on the International Space Station.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Ethan Elliott, and he is an atomic physicist and research technologist at NASA's Jet Propulsion Laboratory in Pasadena, California. He's been working on Cold Atom Laboratory, a really neat piece of research up on the International Space Station, and it's operating right now. Welcome, Ethan, to Gravity Assist.

Ethan Elliott: Thank you, Jim. Very excited to be here.

Jim Green: What exactly is the Cold Atom Lab, Ethan, and what's it trying to do up in space?

Ethan Elliott: So it's a self-contained lab that includes all the seven lasers, all the electronics, and the ultra-high vacuum chamber needed to cool atoms to under a billionth of a degree above absolute zero. It was installed on the interior of the ISS in June of 2018. So it's been operating for about three years. It's created the first Bose-Einstein condensate in orbit, and demonstrated the first atom interferometer in orbit.

Jim Green: So when you talk about the Bose-Einstein condensates, what exactly do you mean?

Ethan Elliott: The Bose-Einstein condensate takes its name from two physicists, you know, we're pretty familiar with Einstein. And Einstein predicted the condensate, but all of that work was based on the work of the Indian physicist, Bose, who very generally worked out these, these quantum statistics that predicted not just the BEC, but know that this whole range of physics involving photons at the time in 1925, and he sent this paper to Einstein and Einstein realized, oh, wow, there, there's really something here and officially translated into German himself. And that's where Einstein's name get, get attached to it.

Ethan Elliott: It's, it's a fifth state of matter beyond solid, liquid, gas, and plasma. But fundamentally, we describe it as a macroscopic quantum object. And I realize that's the kind of answer that gives scientists a bad name because it raises 10 more questions. Right, so what is a macroscopic quantum object?

Ethan Elliott: So a quantum object follows the laws of quantum mechanics, which were rules scientists discovered, when they started studying the smallest objects in the universe like electrons. They found they could behave like waves and particles. And that's very strange, because we know waves and particles are different things. When particles collide, they bounce off of each other. But when waves collide, they can move through each other, or waves can be at different places at once.

Ethan Elliott: And by trapping and cooling atoms, we can exploit a law that quantum mechanics applies not just to the smallest, but also to the coldest. Advances in technology and techniques over the last 40 years, have allowed us to reach these temperatures where we can actually amplify quantum mechanics. So in science fiction terms, we can't shrink something down and enter the quantum realm. But we can enlarge the quantum realm itself. And the experimental machines that do this work better in microgravity, and that's where the ISS comes in.

Ethan Elliott: Another way to think about cold atoms in space is that the cold gives you the amplification of quantum mechanics, while the freefall of the ISS gives you an extension of the amount of time you have to interact with gravity. So that's like a kind of an amplification of gravity.

Jim Green: So when we say cold, how cold is it? And how do you work so hard to make it at that temperature?

Ethan Elliott: So when we when we say cold, we're talking a billionth, less than a billionth of a degree above absolute zero. So you think, “Oh, you know, one degree above absolute zero, that sounds pretty cold.” This is a billion times colder than that. And the way we reach these temperatures, we actually have to start by getting the atoms hot, we take a solid piece of metal, we heat that to about 700 degrees Kelvin, and make a metal vapor. And once that's done, the first stage of cooling uses laser light to corral the atoms near the center of our of, our vacuum chamber.

Ethan Elliott: Lasers cool the atoms that are then loaded into a container with walls that are made out of magnetic fields. And these magnetic fields give the atoms of frictionless bowl to evaporate in, kind of like a like a hot cup of coffee. So the atoms collide with each other, they exchange energy, and a portion of the atoms accumulate enough energy to escape over the walls of the trap, taking that energy away with them and leaving the remaining atoms colder.

Ethan Elliott: And eventually, the evaporation will stagnate when the sample of atoms is cooled so much that no atoms can build up enough energy to escape. But we force the evaporation process to continue by sending in very specifically tuned radio waves or microwaves. And its frequency is chosen so that the atoms can reach a particular magnetic field, where they will have the orientation of their electrons relative to the nucleus altered in a way that changes them from magnetically attractive to magnetically repulsive ejecting them from the trap. And because this slices out the hottest atoms from the trap would call this an RF knife.

Ethan Elliott: And as the temperature drops there, that's where we get into the range of a billionth of a degree above absolute zero, your strange behavior or really, quantum mechanical behavior starts to starts to happen.

Ethan Elliott: So, what a Bose-Einstein Condensate really is, is when enough of the atoms get into this lowest energy state with the largest wavelength, so that you have this collection of ultra-cold atoms with the same wavelength that as far as quantum mechanics is concerned, is the same atom.

Jim Green: Wow, that sounds fantastic. So why do scientists care so much about studying atoms when they get so close and cold in that Bose-Einstein condensate regime?

Ethan Elliott: Yeah, so there are three broad categories of, of uses for ultra cold atoms, and many kinds of experiments in each category. And that's one of the reasons why CAL is a multi user instrument, different scientists want to use it for different things. So you can use ultra cold atoms, one for fundamental science. You know, there's always a state of the art quantum calculation that needs checking. You can also, number two, use the control and organization that you get by cooling atoms to arrange them into models for other systems in nature, such as the lattices of a superconducting metal, or the interior of a neutron star. Or, third reason: You can use atoms themselves as probes of inertial forces.

Ethan Elliott:  By inertial forces, I mean, accelerations, rotations or gravity. And gravity in particular is what really gets physicists interested and raises the single eyebrow.

Jim Green: Ethan, last year, NASA reported that your project and, and all the people in your organization were able to create that fifth state of matter up on the International Space Station. How did you feel when that occurred?

Ethan Elliott: I mean, it, it felt amazing, you know, there was so much work leading up to this, you know, that that rockets leaving when that that rockets leaving, so a lot of a lot of late nights to get everything working. And then, you know, once the atoms are on the on the ISS, there are all these different stages to checking out the the instrument and making that each part of it, making sure that each part of it works. I mean, when the instrument was first powered, and you know, there's just a green LED that comes on for the first time, you know, the “whoa!” You know, the whole room is going, going nuts that they just got this little little light on.

Ethan Elliott: But yeah, so when it when it comes to actually observing these, these ultra-cold atoms, yeah, so how do you observe something this cold? We actually make the sample of ultracold atoms, then we send in a final laser beam that blows the cloud apart, but the atoms that were there cast a shadow on a camera behind this, this laser beam. And that's how we tell what the atoms are doing, tell whether there's a Bose-Einstein condensate there or not.

Ethan Elliott: We start getting these first pictures down that look like they have the BEC spike at the center. And, you know, the physicists in the room are just starting to glance back and forth at each other you know, and to say through our teeth like like is that is that it like that could be it? Oh, boy. No, okay. All right. You know, play it Cool, let's let's get it. Get a couple more of these. You know, make sure it's make sure it's repeatable, okay, all right, that could really, that could really be it. And yeah, that was a great a great moment. But then, you know, then you do have to do your scientific due diligence. And now this has got to stand up to peer review, what's the temperature? What how to how does the How does the BEC flow when we shut the shut the trap off. So yeah, that was, that was a very exciting time.

Jim Green: Well, since then, how many times if you've gotten these atoms in that state, that fifth state of matter, that Bose Einstein concentrate, concentrate, (laughs) condensate?

Ethan Elliott: It is a mouthful. The, you know, it starts out as this, you know, as this huge as this huge milestone, and then it just turns into a daily occurrence. So now when the instrument is started up each day, there is a warmup period for our lasers, and the first stage of cooling is this laser cooling to load atoms into the magnetic trap. And then the next step is okay, you know, confirm that there's a BEC and that's kind of our, you know, our, our daily standard, our daily gate for then starting in on the day’s science.

Astronaut Christina Koch unloads new hardware for the Cold Atom Lab aboard the International Space Station the week of Dec. 9, 2019. Credits: NASA-International Space Station

Jim Green: That's fantastic.

Jim Green: Well, once you get them in that state, these several thousand atoms, what are some of the measurements that you do next?

Ethan Elliott: Well, yeah, I so I talked about these beat these three broad uses for ultra cold atoms, fundamental science, simulating other systems and using the atoms themselves to to make measurements. And that brings us to that something we call a atom interferometer. So an interferometer detects the interference of waves to make measurements, it's an interfere-o-meter, right, and we can now use the quantum mechanical waves that we've created. So we've taken matter and forced it to have a wavelength.

Ethan Elliott: We can use the interference of these waves to give extremely precise measurements of inertial forces like accelerations, rotations, and gravity. And as physicists we are very interested in gravitational measurements.

Ethan Elliott: And scientists don't understand how to combine our best description of gravity, which is general relativity, with quantum mechanics, which is our, our best description of the macroscopic world. You know, General Relativity says that mass distorts space time and moves around in a curved space time. But quantum mechanics says that, you know, mass can also be a wave and kind of being in two different places at once and how to combine that we don't don't really know how to how to do yet. And if there's a problem with these theories, it's not it's not the logical steps of the theories themselves. If there's a problem with these theories, it's all the way back at the fundamental assumptions that went into them.

Ethan Elliott: So one of the fundamental assumptions of general relativity of gravity is something called Einstein's equivalence principle, which, basically, if you were to stand at the top of the Leaning Tower of Pisa and drop your your pebble and your boulder, it should hit the ground at the, at the same time. That might not actually be true. And if you were to, for example, take two quantum mechanical matter waves, you know, that have different masses say one's made out of rubidium one's made out of potassium, and you drop those matter waves simultaneously in an interferometer, do they fall the same? And if you do that, not only are you very accurately testing this fundamental assumption of, of gravity, of general relativity, but you're doing it with quantum mechanics.

Jim Green: Fantastic. Well, I heard that it wasn't too long ago that we brought up to the International Space Station and upgrade to the experiment. What were some of the changes that were made from the first implementation of Cold Atom Lab?

Ethan Elliott: So that's, that's one of the great things about being on the ISS that there's a human presence, right. There's astronauts that are available to upgrade the instrument, or, or fix it, if something were to go really wrong, which we haven't, haven't needed yet.

Ethan Elliott: So, the atom interferometer that I talked about, that was installed in January of 2020, by astronaut Christina Koch. The atom interferometer was installed as part of replacing the heart of the instrument, this, the science module, and the science module contains the ultra-high vacuum chamber that you need for the thermal isolation of the atoms from the environment. So you the atom cooling happens inside a vacuum chamber to even allow them to be to be cold.

Ethan Elliott: This is really the, the heart of the instrument. So that was replaced about a year and a half ago, but just this this July 15th, we had a new upgrade that was installed by astronaut Megan McArthur. And we're actually now just in the, in the process of, of testing this now.

Ethan Elliott: So this upgrade, it's a, it's a new frequency source, it's a new source of microwave photons that we can use to manipulate the ultra-cold atoms And it's going to allow us to cool not just one species of atoms, but two and this opens up many new possible experiments.

Jim Green: Well, Ethan, what is your role in working with the JPL team on Cold Atom lab?

Ethan Elliott: Look, I have the best job that there is. I study quantum mechanics in space. Officially, I'm the lead of the engineering model testbed, which is a copy of the instrument on the ground where we test new upgrades, or troubleshoot problems. I'm the deputy lead of CAL’s flight operations. And I'm one of the scientists using this instrument to collect data and conduct experiments. And there are teams all over the world using this instrument for their own experiments, including three physicists that were such pioneers of this field of atom cooling and trapping that they already have Nobel prizes.

Jim Green: Well, Ethan, I always like to ask my guests to tell me what was that event or person, place or thing that got them so excited about being the scientists they are today. I call that event a gravity assist. So Ethan, what was your gravity assist?

Ethan Elliott: Well, generally, I think I was always excited to be a scientist. And I wish I could say it's because I grew up reading Newton or Einstein, or the Feynman lectures or anything by actual great scientists of history. But no. As a kid, what excited me was when I would turn on cartoons after school, and watch space adventures and superheroes with the understanding that most of the superheroes were scientists, right? It was always some crazy invention that would save the day or the, or the superpowers themselves were derived from a freak accident in the lab.

Ethan Elliott: And honestly, if you don't mind, something that I'm very passionate about is not what brings students into science, but how they manage to stay in science when it gets tough, and it will get tough. And, but I've been very lucky to have had great mentors through undergrad and outstanding graduate advisor and mentors at JPL. I think there is great science outreach to get students excited. But I'm most interested in reaching the undergrad and the graduate students who are already working in science have put in so much work, but are starting to just feel overwhelmed or maybe that they can't do this, or that they've made a mistake. And I just want them to know that it's it's going to work out and to keep going.
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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #25 dnia: Maj 21, 2023, 07:24 »
Gravity Assist: Freaky Physics on the Space Station, with Ethan Elliott (2)

Ethan Elliott is the lead of the Cold Atom Laboratory engineering model testbed at NASA’s Jet Propulsion Laboratory in Pasadena, California. Credits: NASA/JPL-Caltech

Ethan Elliott: I think motivation or the ability to keep going comes from the story or a narrative that we tell ourselves and the trouble starts when we hit something where that story fails. So, let me try to quickly explain how once the story I was telling myself failed.

Ethan Elliott: In my PhD, I was working on a very specific application of ultra-cold atoms to test consistency with a string theory conjecture. I had to learn all day, all this hydrodynamics and thermodynamics. And to do that I was reading rocketry textbooks, and really starting to wish I had done something more space-related. But why would NASA hire a cold atom scientist?

Ethan Elliott: So I got it in my head that I needed to demonstrate what a good physicist I was, to be a successful scientist, I would need to graduate in five years. So then towards the end of my fourth year, my entire experiment need to move from one university to another, you know, meticulously aligned optics, diode laser 130 watt, carbon dioxide, laser, optical fiber is laser walking electronics, power supplies, high back and components, control hardware, you know, the whole deal. And I thought my, my career was over. I had given myself completely made up deadline that was now impossible. I thought I was a complete failure, you know, that the narrative that I've been telling myself is broken. And I thought seriously about quitting. And I only snapped out of it with a new story: you know, that the conviction that okay, a true scientist would show the knowledge, skill, patience, to personally rebuild an ultra-cold atom experiment from the ground up, and know, maybe better than it was even.

Ethan Elliott: And I graduated, and my advisor told me that he saw an ad that NASA was trying to build a cold atom experiment to put in space. And yeah, I thought, you know, the, sign me up for that I was on the plane to that interview so fast. And then the drive to to move my family out to JPL. So I just want any student to be very careful about the story that they're telling themselves and make sure that it's not made-up nonsense. They can, they can generate their own gravity assist, kind of, by changing their perspective. And now, when things go wrong in the lab, you don't get literal superpowers. But those are the times that that make you better. And you know, you make mistakes in school so that you don't later and no one asked me now how long I was in school, but they do ask me to lead troubleshooting on the only quantum lab in orbit. So to any graduate student alone in a dark lab right now: Don't quit. It's going to be okay.

Jim Green: Yeah, that's absolutely tremendous advice. I mean, I remember, of course, in my own graduate career, the ups and downs that occur. But indeed, you've got to be able to be passionate, and stick it out and find your way. And I'm so delighted you were able to do that. Ethan, thanks so much for joining me and discussing your fantastic experiment and your important career that led you to Jet Propulsion Laboratory.

Ethan Elliott: Thank you so much, Jim. Great conversation.

Jim Green: Well, join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green, and this is your Gravity Assist.

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Aug 6, 2021
Editor: Gary Daines

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #26 dnia: Maj 28, 2023, 08:57 »
Rozmowa ze specjalistką misji Cassini , a po jej zakończeniu LRO, Sentinel-6, SWOT

Gravity Assist: Goodbye Saturn, Hello Earth, with Janelle Wellons (1)
Aug 27, 2021

Artist's concept of the Cassini spacecraft diving between Saturn and its innermost ring. Cassini’s mission ended by plunging into Saturn in 2017. Credits: NASA/JPL-Caltech

Janelle Wellons likes to say that she operates “fancy space cameras.” At NASA’s Jet Propulsion Laboratory, she creates commands that allow spacecraft to take valuable scientific data in our solar system and here at planet Earth. She also monitors the health of spacecraft, like a space robot doctor. She has worked on the Cassini mission to Saturn, the Lunar Reconnaissance Orbiter, Sentinel-6/Michael Freilich, and more. In this episode, she reflects on her experiences at JPL and why outreach and diversity and inclusion efforts are so important.

Jim Green: Every spacecraft that NASA builds is so unique, whether they orbit Saturn or the Earth. Let's talk to an instrument engineer that creates the commands that tell our instruments what to measure.

Janelle Wellons: Space is not this gatekeeper that says if you didn't make it after college, then it's not for you. Space is a place for everyone.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Janell Wellons, and she is an engineer at NASA's Jet Propulsion Laboratory, or JPL, and it's in Pasadena, California. She has worked on missions to the Moon and Saturn and right now, also here at Earth. Welcome, Janelle, to Gravity Assist.

Janelle Wellons: Thank you so much. I am so excited to be here.

Jim Green: Well, I'm, I'm just as excited having because we're going to talk about your activity and what led you to JPL? How did, how did you get your, what I would say, your dream job? Right.

Janelle Wellons: Right. Right. It was definitely not a clear shot, I could tell you that much.

Janelle Wellons: So you know, I'm a kid in New Jersey. Neither my parents are in the sciences or engineering. But my parents from a young age instilled in me that curiosity was always going to be a good thing. And so that meant when I went to Toys R Us, I didn't just have to go into the pink aisle with all the Barbie dolls and the kitchen sets. I was allowed to go to the blue aisle, too.

Janelle Wellons: And that…

Jim Green: Cool.

Janelle Wellons: Made all the difference for me thinking about what my future could be. But it also kind of led to some issues. I call them issues and maybe they're not so much of issues. Because I got to high school, I realized that all of the classmates around me, they knew exactly what they wanted to do. And I didn't even know where to start. It wasn't something that was at the forefront because my parents, they also didn't graduate from any four-year universities.

Janelle Wellons: But I was actually getting mail addressed to me from colleges, all around the nation college, they had never heard of talking about their track programs, talking about, oh, we have this kind of math major, or this kind of literature. It was amazing. But it was also overwhelming. I was taking these letters, I was storing them in a container underneath my bed. And when I ran out of room in the container, they were going in the trash can.

Jim Green: Okay.

Janelle Wellons: My mom turns and happens to notice there's a pamphlet for school called the Massachusetts Institute of Technology, was a school I had never heard of in my life. But my mom, thank goodness for my mom, she had heard of this school. And she said, You need to look at this. This is a great school.

Jim Green: Yes, MIT.

Janelle Wellons: MIT. (laughs)

Janelle Wellons: And so we did look at it, we spread it out on the kitchen table. And it was talking about how they had this summer program for juniors going into their senior year. And you're going to learn all about the sciences and you're going to be all these other students from around the nation and if you get in, it's also totally free of cost which, my mom's saw that part and she's like, “You're applying to this.”

Janelle Wellons: I went back and realized that the previous year, they had over 2000 applicants and only admitted one person from New Jersey. “Like, Oh, well, it’s a wrap, I’m definitely not getting in.” I mean, come on. I'm not even top of my class in the middle of nowhere New Jersey, sorry. I just didn't think, you know, that, why would choose me? I'm not the perfect SAT. I'm not the perfect grades. And so when my mom called me that spring, saying “you need to rush home, there's a package in the mail,” I’m like, well, we already went over this, but fine, I'll come home.”

Janelle Wellons: And I opened it up and saw that word, “congratulations.” It changed my life.

Jim Green: All right. So then you graduate. How did you get to JPL from there?

Janelle Wellons: Well, I was taking all these classes in my major. And my professors kept on talking about this NASA JPL place. That three-letter word was just everywhere. Oh, let's pretend we're gonna land something on Mars, like JPL. Let's pretend we're gonna send a spacecraft out of our solar system like JPL. It's like, this name just kept coming up, coming up. And suddenly a place I didn't know. I started to know. And I started to become really interested in working for JPL. I mean, cool space robotics! Like, if I'm going to study aerospace engineering, then I want to work for them. They seem super cool. And so because of that, of course, I was going for the internship every year, getting in that line of the career fair, holding my resume, listening to my classmates in front of me talk about all their cool projects, hoping that maybe I'll be cool, too. (laughs) But I never landed the internship.

Janelle Wellons: And I'm glad that it happened the way that it did, because I realized that even I didn't believe that I was an engineer at that point. It took until my senior year to really start getting the confidence that I belonged here.

Janelle Wellons: And I remember it was right around Thanksgiving, that I got a phone call. Phone call was coming from I believe someone in HR saying, “hey, has anyone talked to you about salary yet?” I said, “Salary? Wait a second! Did I get the job?” He’s was like, “Oh, wait. You didn't hear that yet? Yes, you did.” I said, “Excuse me,” while I put ‘em on mute. And I had the biggest celebration you can imagine right there, my dorm room jumping up and down. I couldn't believe it. I finally landed the job at JPL. And not long after that, when I graduated from MIT, I flew out to California for maybe the third time in my entire life, and started my new life here, working there.

Jim Green: Fantastic. Well, you followed your passion. And because of that, you met your goals. And they are lofty goals. So your first mission at JPL was Cassini, I found out. Well, can you tell me more about what you did working on Cassini?

Janelle Wellons: Absolutely. So I'm starting at JPL. I’m a new person, nervous all over again, because you got the job and now it's time to prove yourself, right? And when I was hired, I was hired into a group that does instrument operations engineering. But to be quite honest, I really did not know what that was, you know, between the interviews and talking to all the people, your excitement can get the best of you, and you're just excited to be there.

Janelle Wellons: And soon I found out that this this job of instrument operations engineering, basically meant that I could do some of the coolest things imaginable. Because on Cassini, I learned what that job title was all about. It was about basically operating the scientific instruments that we put on the spacecraft that go to all these places, so that we can learn more about them -- the how, the why, the what, all those questions asked by the scientists, I was there to make it happen.

Janelle Wellons: And so I was trained on Cassini to generate commands that had the ones and zeros, the machine language and our instruments can understand. And in particular, on this mission, I was commanding the imaging science subsystem, and the visible and infrared mapping spectrometer, but I kind of like to call them fancy space cameras, because the end product that you got from these instruments, were these absolutely beautiful images of Saturn, its rings, its moons. I mean, seeing those images come down and realizing that we're there. We captured this, this isn't an artist's rendition, this is real. I was sending them to my friends. They just they couldn't believe it. I couldn't either. But that was my job: commanding these instruments, these cameras and getting back these wonderful pictures.

Janelle Wellons: And the other half of it was making sure that things were running smoothly. You know, we kind of talk about instruments and spacecraft like their people sometimes, making sure they're healthy and safe. And I kind of like to compare my job to somewhat like a doctor and their patient, you know, you come in, you're not feeling so well. They look at the charts and: Oh, your blood levels are spiking all your temperature’s high. It's the same thing that we're doing every day that we come into work, we're looking at the charts of the instrument: is the voltages doing okay, the currents, the temperatures, all the commands, are they executing the right way. And over time, you really get to know how your instrument behaves, and when things are going well, or even when they're not going well, even if it's not because it's out of a limit, just because you have a good understanding of how it works.

Janelle Wellons: Cassini was actually this really amazing part of its journey. It was at the end. We were approaching fastly approaching the grand finale of the Cassini mission.

Jim Green: That’s right. That's right.

Jim Green: And while you were doing that, while you were out there working on the instrument, I was NASA Headquarters. And I don't know how you felt when we decided Cassini needed to die by plunging into Saturn in 2017, but I'm the one that signed off on it.

Janelle Wellons: Are you serious? Oh, my goodness.

Jim Green: Yeah. Yeah. Yeah, It was a, it was something that had to be done because the what we found in terms of the possible life on Enceladus, and Titan was such a fantastic moon, that we just couldn't risk the spacecraft hitting either one of those moons.

Janelle Wellons: Yeah.

Jim Green: So we, we needed, we needed to plunge it into the atmosphere. So how did you feel when that happened?

Janelle Wellons: I feel honored. I’m meeting the man who signed the line, who brought the end to Cassini, a very fitting and to Cassini, too. When I heard that news. Honestly, I was so excited. I could not believe my luck. I’m on my first project at JPL and you're telling me that we are purposefully going to destroy a spacecraft? I’m like, when is the next opportunity that this is gonna happen for me? I was psyched. (laughs)

Jim Green: Unfortunately, it was me, but JPL proposed this fabulous mission of jumping in between the rings and the clouds of Saturn. Wow, what's not to like about that?

Janelle Wellons: Yeah.

Jim Green: We've learned so much from that.

Janelle Wellons: I realized over time that I needed to kind of keep my excitement on the inside a little bit. ‘Cause I got the feeling that maybe not everyone around me was quite as excited as I was.

Jim Green: They were very sad. They were I know, I you know. So I was in the control room when it happened. And it was a rather somber affair.

Jim Green: Mhm.

Janelle Wellons: I was at Caltech, and we were watching on the screen, everybody in mission control. And at the end, when everyone stood up, and we announced the end, and people were hugging, I saw. And he was crying like ugly tears crying.

Jim Green: Yeah, I know.

Janelle Wellons: when I saw him do that. I started crying, the hardest I ever had. This team was like a family. And they were the family that welcomed me. And it was going to be the start of the end to that too. Maybe at JPL. But of course not in our personal lives outwards. We still meet. I'll never forget it because of that.

Jim Green: Well, after Cassini did you get involved in your next big mission? Was at the Lunar Reconnaissance Orbiter?

Janelle Wellons: Yes, it was. So while I was working on Cassini, I started to learn about that project. And I started to learn that half my time will be spent on the Lunar Reconnaissance Orbiter. And so I joined that team. And it was in stark contrast to the Cassini team, because of the sheer size of it. So I went from working with all these people to be on a team of five at JPL. And it was a big change, but a very cool one. It kind of showed me that there are so many differences in the missions that we operate and how we go about them what the team dynamic is. In this case, on LRO, I was going to be operating the Diviner instrument.

Janelle Wellons: That's a radiometer. And so being on LRO was very cool. Because one, I remember being able to go outside at night, look at the Moon and say, we're there. Like we're there.

Jim Green: Wow. That's right.

Janelle Wellons: And in the very beginning, I was sending commands in real time, like on the headset, with the folks out at NASA Goddard who were in charge of operating the spacecraft and getting all the official lingo like command on the way or go for uplink it was just so cool.

Jim Green: Diviner is a fabulous instrument, measuring the temperature the surface. This is how we know those permanently shadowed areas are colder than the surface of Pluto. And it's from the diviner instrument on LRO.

Janelle Wellons: Colder than Pluto! That's really cool.

Jim Green: They, they are, you know, and so volatiles fall on them, you know, water’s in there and it's just not coming out because it's just frozen solid. So that's one of the reasons why LRO is such a fabulous mission. Now it's still operating.

Janelle Wellons: Yeah.

Jim Green: Are you still involved in that? Or did you go on to something else?

Janelle Wellons: I'm working on three Earth missions, which is not something I ever imagined for myself coming to JPL. Because like I said earlier, I knew them from the Mars, and the Venus and the Sun and Saturn, I didn't really know them for Earth. Come to find out though Earth is one, a planet and two, our home, so why wouldn't we be doing all this great science for our own planet?

Jim Green: Right.

Janelle Wellons: And so while I was working on LRO, I started to get introduced to this project called the Multi-Angle Instrument for Aerosols. I didn't know much about it, but I was told by my supervisor, this is something you want to be involved in early on. I said, “Yes, ma'am. I definitely trust your judgment.” And she was right. I joined that project very early on.

Janelle Wellons: And I think what makes this project truly special, is that its mission is something that is absolutely, absolutely going to impact people here on Earth. Because MAIA, MAIA is this instrument, it's a camera, ‘course, the fancy space camera, that's going to be measuring particulate matter, or pollution, in cities all over the world. And by measuring this pollution, they're also going to be doing health studies in those same areas.
« Ostatnia zmiana: Czerwiec 04, 2023, 07:42 wysłana przez Orionid »

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #27 dnia: Maj 28, 2023, 08:57 »
Gravity Assist: Goodbye Saturn, Hello Earth, with Janelle Wellons (2)

Janelle Wellons at NASA’s Jet Propulsion Laboratory. Credits: NASA/JPL-Caltech

Jim Green: So, in addition to MAIA, you're also working on a couple other Earth science missions. What are they?

Janelle Wellons: Yes, I am also working on a mission called Sentinel-6 that launched last November. I was on the team then wish I was because oh, man, can you imagine your project being launched just the adrenaline to be there to see your accomplishment? But I'm so happy I'm on it now. Because when I joined, they were doing a lot of very cool activities to make sure the instruments were performing the way they should be. And so I got to do that real time stuff again, on the console. Everybody paid attention. Are you ready? Watching the telemetry or the monitoring the, the temperatures of voltages, the things we spoke about before. And I'm also on this project called SWOT. And SWOT is not yet in space, but it is making its way shortly there. It is in the lab, is being integrated, put together tested, we're in that phase of development. And it's my job in that capacity to figure out once again, how we operate this once it actually gets up in space.

Jim Green: Now, of course, Sentinel-6 is also called Michael Freilich and Michael Freilich was the division director of Earth science when I was the planetary science director. And so Mike and I were good friends. And he has passed away. And I'm delighted that Sentinel-6 has been named after him.

Janelle Wellons: I wish I had had the pleasure to meet him. And sounds like you were really good friends. I'm sorry for your loss, but so happy because his legacy obviously, is, is living on.

Jim Green: Well, you know, I know you enjoy public outreach activities. And so when you talk, what does the public want to know?

Janelle Wellons: You know, when I talk, my goal, my mission is, it may be seem like it's a simple one. But it's just to inspire at least one person in the room. I don't care who it is, because inspiration doesn't stop when you're just a kid. Space is not this gatekeeper that says “if you didn't make it after college, then it's not for you.” Space is a place for everyone.

Janelle Wellons: So when I do outreach, my goal is specifically to talk to people who may not think that it's possible for them to one day work for NASA, kind of the same way, I wasn't exactly thinking it was possible for me to one day, and share with them that not only did my journey feel very much full of chances, opportunities, maybe it wouldn't have even happened if not for a pamphlet in the mail. But also not giving up after the first bit of failure, of rejection. That's a part of what actually helps you grow and helps you get better. And so that's the message that I like to share. So that by the end, there’s someone out there who may not have thought that this was for them, who now thinks, “I can do it too.”

Jim Green: Janelle, you work in the diversity and inclusion activities at JPL. What's that like? And what do you guys do?

Janelle Wellons: I got into the diversity, inclusion and equity part of the lab, honestly, because when I came into JPL, I was looking for that community. I was wondering to myself, “you know, I'm out here in California by myself, you know, my whole family's back on the east coast. And here I am. It would just really be great if I had a community of people, specifically of black engineers, who can relate to my experience in a lot of ways, that I could just talk to.” And so after doing some digging, we found there was an organization out there, but they had kind of been dormant, doing maybe one event per year. And I proposed: Do you mind if me and some of my friends revive this? Can we make this something new? And they gave us the total thumbs up with support. And that's exactly what we did.

Janelle Wellons: And at first, we went from building the community: let's all go for a hike, let's meet in the cafeteria for games on Friday, during lunch. But we were able to grow so much more beyond that, especially with the help of the other employee resource groups at the lab. And we went from building that community to using that community to institute real change that can only improve NASA as a whole, to make that future for those who never imagined themselves in a place like this, who maybe have never pictured themselves as an engineer, because maybe they've never seen someone who looks like them in that space.

Janelle Wellons: So now, we're out there doing outreach for K through 12. for going to the conventions, we're recruiting, we are helping the lab with creating new events to allow employees to talk with each other about the experiences that we go through to really just make that inclusive environment that NASA is all about. And so I'm so proud to be involved in all those efforts. And I'm looking forward to all the great things that will come from it.

Jim Green: Well, that's fantastic. Because Janelle as you know, so well, many of our young students don't see a future in some of these things. They don't even know what's going on in some areas. So getting them exposed and being that, you know, role model that you are is a huge step to help them on their way. And I'm sure you're giving gravity assists along the way.

Jim Green: Well, Janelle, I always like to ask my guests to tell me what was that event or person, place or thing that got them so excited about being the engineer they are today? I call that event a gravity assist. So Janelle, what was your gravity assist?

Janelle Wellons: My gravity assist happened my freshman year at MIT. So I come out of that program. I was so excited to be there. And I realized that I didn't exactly know what I wanted to do. I knew that math was cool, for sure. I absolutely loved math. And I convinced myself, I was going to become a theoretical mathematician.

Janelle Wellons: And all these upperclassmen were telling me, “you know, MIT is a school that's known for its engineering. So we’re just gonna encourage you to take at least one introductory class to engineering.” All right.

Janelle Wellons: But then I came across one called aerospace engineering. And I was the type of kid who was up watching Jimmy Neutron building a rocket in his backyard and launch into space thinking, “How can I be the kid in the neighborhood that does the same thing?” And you know, the black hole videos late at night. You know, space is cool. I don't know many people who don't think so.

Jim Green: That’s right.

Janelle Wellons: And so, how about I give that one a try? And this is when the gravity assist comes in, because I'm in the class on the first day, and the professor is going over the syllabus. And he's talking about how we're going to learn the rocket equation, we're going to learn about how planes fly. And we're also going to learn a little bit about the history of spaceflight. And he shows this image of an astronaut fixing the Hubble telescope. And I remember looking at that, and thinking, “this is unreal. Some people really, they have a job that lets them work on something in space? And then my professor, Professor Jeffrey Hoffman, says that he is the man in the photo.

Jim Green:  Yes, he is. Jeff is a very good friend of mine.

Janelle Wellons: Wow. I mean, I think I may have been the only person in the room who didn't know who he was prior to that class. Because I seem to be the only one with my jaw on the desk in disbelief that I was in the same room as an astronaut. Are you serious? Never met anyone from NASA. You’re telling me my professor is an astronaut? That moment, that moment was everything for me because I couldn't imagine turning down the opportunity to learn aerospace engineering from someone like him. And, you know, I went on to continue with the major knowing nothing about this subject, but learning every step of the way. And even doing an internship where he was my mentor over in Italy, and them rolling out the red carpet for him because he had flown with the Italians in space. I mean, he doesn't even know this, he likely does not know this. But he was the gravity assist that really set me on this path to be here at JPL.

Jim Green: Well, that's fantastic. Well, Janelle, thanks so much for joining me in discussing your fantastic career.

Janelle Wellons: Thank you so much.

Jim Green: My pleasure.

Jim Green: Well, join me next time as we continue our journey to look under the hood at NASA and see how we do what we do. I'm Jim Green, and this is your Gravity Assist.

Jim Green: Gravity Assist is going to be taking a mid-season break. Come back in October when we’ll discuss the Lucy mission to the Trojan asteroids, space weather, and much, much more. In the meantime, check out other NASA podcasts at

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Aug 27, 2021
Editor: Gary Daines

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Odp: [NASA Gravity Assist] : Season 5
« Odpowiedź #28 dnia: Czerwiec 04, 2023, 08:48 »
O tym jak to kiedyś mogło być i o oczekiwaniach związanych z misją Lucy.

Hal Levison: What we learned when we looked at this particular period of evolution, is that the Trojan asteroids, which are the this population of asteroids that lead and follow Jupiter's orbit by about 60 degrees, get captured into their orbits during this evolution. So let me explain a little bit more detail about what we're talking about. We envision that the giant planets formed in a much more compact configuration. Jupiter, Saturn, Uranus, and Neptune, all forming within let's say, 12, 13 astronomical units from the Sun right now, Neptune's out at 30 astronomical units.

Gravity Assist: Lucy and the Space Fossils, with Hal Levison (1)
Oct 8, 2021

NASA’s Lucy mission will study the Trojan asteroids. It is scheduled to launch in October 2021. Credits: NASA

The planets of our solar system didn’t have such stable orbits a few billion years ago. The giant outer planets moved around chaotically in their orbits, and Uranus and Neptune may have even switched places. To get a more complete understanding of the full history of our solar system, NASA is sending a spacecraft called Lucy to investigate the Trojans, mysterious small objects that share an orbit of the Sun with Jupiter. Principal investigator Hal Levison of the Southwest Research Institute’s branch in Boulder, Colorado, discusses this exciting mission, launching Oct. 16, 2021.

Learn more about the Lucy mission


Jim Green: We're launching the mission Lucy. It's going to a special place in Jupiter's orbit, where objects called Trojans are captured. What are they? And what can they tell us about the evolution of our solar system?

Hal Levison If you think about it, almost everything is chaotic. The stock market, the weather, everything is chaotic. And so is the solar system.

Jim Green: Hi, I'm Jim Green. And this is a new season of Gravity Assist. We're going to explore the inside workings of NASA in making these fabulous missions happen.

Jim Green: I'm here with Dr. Hal Levison. And he is the principal investigator of a fantastic mission called Lucy. And he's based out of Southwest Research Institute in Boulder, Colorado. Lucy will be launching very soon, and will be visiting some of the very special asteroid objects that share an orbit with Jupiter. So welcome Hal to Gravity Assist.

Hal Levison: Oh, it's my pleasure to be here. I can't wait to fill you in and let your listeners know about the Lucy mission. It's very exciting.

Jim Green: It is very exciting. But I want to start, actually, a little earlier. What got you into studying how the solar system evolved? And how it may have even moved around over time?

Hal Levison: Well, when I was a kid, I was always interested in asking the questions where we came from, how we got here, how the Earth got the way it is. And so the study of planet formation, you know, was just filling in one of the niches of that question, right? I mean, obviously, there are many aspects of that question from cosmology all the way up to evolution. Right? But for me, I decided working on trying to understand how the Earth and the other planets got to be, is really what my passion is.

Hal Levison: My whole career has been trying to understand how planets came by building large numerical computer simulations following the orbits of things around the Sun as they accrete to form the planets.

Jim Green: What's really neat about that whole concept is that it led you to some really exciting discoveries. The concept of how planets form, and then how they interact with each other, and actually move their orbits based on that interaction. That that is a fantastic story, you know, moving something the size of Jupiter and Saturn, Uranus and Neptune. How did that come about?

Hal Levison: Let me take a step back, right, because, you know, the concept of planet formation back when I got into this field, I'm a gray beard at this point in my career, was the planets sort of formed out of a narrow region of what we call the protoplanetary disk, which is made of gas and dust.

Hal Levison: And the planets slowly accumulated objects around that.

Hal Levison: What we did, through my career, over the last 20 years or so, was to understand that that's not how planets form. Planet formation is actually very violent. The system evolves together, right. So rather than having this little isolated region where the Earth grew, materials handed back and forth between the planets as they grow, the planets are pushing each other around. They're competing for resources, the ones that are successful grow, and become the planets that we see today.

Hal Levison: And it was that understanding of this evolution from a very quiescent situation to a very violent one that sort of led us to this understanding that the planets had to move around. And in particular, what we noted when we tried to run our models of the outer solar system, is that you can never build Uranus and Neptune where we see them today.

Hal Levison: Jupiter and Saturn, which are closer to the Sun, and thereby, in the standard picture form much faster, much faster, stop Uranus and Neptune from growing at all. So we needed to come up with an idea which allowed the four giant planets to grow together.

Sharing Jupiter’s orbit around the Sun, the Trojan asteroids may hold clues to the evolution of the solar system. NASA’s Lucy mission will explore them. Credits: NASA/JPL-Caltech

Hal Levison: And what, what we came up with was the idea that they formed as a very compact group, as a system of four planets. And then we needed to get Uranus and Neptune out where we see them. Right?

Jim Green: Right.

Hal Levison: And that led to this, what we call it, we call it the Nice model, which is a really a global instability, where the orbits of the planets become really become nuts. And they cross each other and gravitationally scatter each other around -- gravity assists, right? Jupiter, Saturn gave Uranus, and Neptune a gravity assist to basically kick them out to the orbits we see today.

Jim Green: So Hal, in the Nice Model, did the order of the planets remain the same? Or did they change places?

Hal Levison: Um, it depends on the details of the model. Jupiter, and Saturn, their orbits remained the same. Uranus and Neptune. It's about 50-50, which one ends up the inner planet and which one is the outer planet. There's also a version of the Nice Model, which is actually becoming quite popular at the moment, where there was another ice giant that was actually ejected into interstellar space during this event, so that the solar system originally had nine planets in this idea, and now it's down to eight.

Hal Levison: The reason why we need this extra planet is because we need gravitational interactions between Jupiter and this planet to get the orbit of Jupiter, right.

Jim Green: Oh, interesting.

Hal Levison: But once Jupiter grabs on to one of these things, the most likely scenario is it gets ejected.

Jim Green: Completely out of the solar system.

Hal Levison: Completely out of the solar system.

Jim Green: Wow, OK.

Hal Levison: So it's, it's, it's gone. It's history. If this is right.

Jim Green: And isn't it true that the small bodies tell us this telltale sign of the dynamics of the solar system in its early formation?

Hal Levison: It's the place to look, right? The way I like to put it is the small bodies are the fossils of planet formation, right? The planets evolved from them by accreting them and growing, right. That's, by the way, why we named Lucy, Lucy. It's named after the human ancestor fossil that we know, right? Because these things are really the places to go. Right? If you want to understand the history of planet formation.

Hal Levison: So that's why NASA and other space agencies have put so much effort into understanding these small bodies, because they tell us about our history.

Jim Green: Yeah, that's fantastic. And of course, Lucy is going to go to several small bodies. How did you make the decision to go to certain small bodies to uncover this early dynamical period of the solar system?

Hal Levison: What we learned when we looked at this particular period of evolution, is that the Trojan asteroids, which are the this population of asteroids that lead and follow Jupiter's orbit by about 60 degrees, get captured into their orbits during this evolution. So let me explain a little bit more detail about what we're talking about. We envision that the giant planets formed in a much more compact configuration. Jupiter, Saturn, Uranus, and Neptune, all forming within let's say, 12, 13 astronomical units from the Sun right now, Neptune's out at 30 astronomical units.

Jim Green: Wow, yeah.

Hal Levison: So that gives you how the scale of the solar system changed during this time. And that there was this disk of small bodies, outside the orbit of the giant planets, that extended out through about 30 AU where we see Neptune today. We believe, or this model predicts is probably a better way of putting it, that the stuff that's in the Trojan swarms now are a remnant of that disk that originally formed outside the orbit of the giant planets.

Hal Levison: And that disk is now gone. Because Uranus and Neptune went through it. Most of it is in interstellar space. And the way to understand what that period of time looked like and what that disk looked like, is found in the Trojans.

Hal Levison: So that’s sort of the theoretical reason to go to these bodies. There's another aspect of this, right? If you look around the solar system, there are several small major small body populations and the Trojans because they're sort of at the edge of what we can do with solar power missions are the ones we have yet to go to. So they're the ones that are really, are not explored. And in addition to that, right, because of their proximity to Jupiter, they're the only small body population that isn't supplying us with meteorites. So in a way, we have less information about the Trojans than any other small body population in the solar system.

Jim Green: You know, not all small bodies are created equal, so to speak, you know, we've got the rocky asteroids in the asteroid belt, but as you go further out, there's a lot of small bodies that are in the Kuiper belt. So when we say these objects, Trojan asteroids, are captured around Jupiter, do we believe they're all from the asteroid belt?

Hal Levison: This model would predict that these objects, the Trojans, formed in this disk beyond the orbit of the planets, but we don't know that for sure. We need the data. Right? So that's one reason why we're doing Lucy is to get the data to test our theories about the evolution of the outer planets also, because according to the Nice Model, these objects formed at different distances from the Sun, they should have different compositions because at different distances, you have different temperatures, right.

Hal Levison: And so as a result, we should be able, by looking at these things close up, determine sort of where they formed, hopefully…

Jim Green: Mhm.

Hal Levison: …how they formed. And we hopefully can put that together with a story of the migration of the planets to figure out the history of the solar system. That's the overarching goal.

Jim Green: Right. And that's what Lucy is all about. And it's launching very soon. So how do you feel about that? (laughs)

Hal Levison: I'm scared.

Jim Green: (laughs)

Hal Levison: But the, I mean, it's been, it's been one hell of a ride. We started working on Lucy, in March of 2014. For all these years, until about a year, year and a half ago, it was just Power Point slides, and CAD diagrams, and things like that. And so over only about a year and a half, a very short period of time, it's gone from something that's on paper to really, a real spacecraft that's completed. The beginning of the launch period is October 16. So that's very exciting.

Jim Green: You're not just going to visit one object. How many of these Trojan asteroids are you going to visit?

Hal Levison: We are breaking records. So we're visiting eight asteroids. No other mission is gone that before, seven of which are Trojans. We rattle around the inner solar system for a while and use Earth gravity assists to actually pump up the orbit of the spacecraft so it can get out as far as Jupiter. On the way out, it passes a main belt asteroid, which we've named after Donald Johanson, the discoverer of the Lucy fossil.

Jim Green: Right, very appropriate.

Hal Levison  Yeah, thank you. And that's actually an interesting object, in and of itself, because it is part of an asteroid family, which formed about 130 million years ago. So it's one of the youngest objects in the solar system. And then we're heading out to the Trojan swarms. We are going to do two orbits around the Sun. The first we'll take us through the L4, the leading swarm. And then we come back to the Earth, do an Earth gravity assist, and go out to the trailing swarm which is called the L5.

Jim Green: Well, how many Trojans are there trapped in the Lagrangian point L4 and L5 at Jupiter, do you think?

Hal Levison: There are, estimates are there are a couple million.

Jim Green: Wow!

Hal Levison: Of these things there. Most of them are really small, right? There are only a few thousand that are what we would call macroscopic big things like the ones we're going to.

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Gravity Assist: Lucy and the Space Fossils, with Hal Levison (2)

Hal Levison is the principal investigator of NASA’s Lucy mission. Credits: NASA

Jim Green: So after you go to L4, and visit a couple of the Trojans, why do you have to come back to Earth and get a gravity assist to go to L5?

Hal Levison: Well, we need to do this, and we need the gravity assist in the beginning, in order to save fuel. Right, putting together a trajectory like this is actually very difficult. And it's limited by the mass of the spacecraft, which includes the fuel at launch. So if we were going to try to go, let's say, directly from the L4 to the L5, it would require fuel tanks that are just way too big. And so the trick that we're using here is to use the Earth as a targeting mechanism. That's why we have three Earth gravity assists through the entire mission. We're letting Earth do the work rather than our main engines, and that saves fuel and makes the spacecraft lighter, which saves fuel and money in the long run.

Hal Levison Let me just give you a little bit more background of Trojans. One of the interesting, and some surprising aspects of this population is when you look at them, they're very different from one another. Right? This is, this is what leads people to believe that they formed at different locations in the solar system or were captured. But in order to understand what they're telling us about the history of the solar system, we have to understand that diversity. And so Lucy itself was designed to visit as many of these things as we could. The planets literally are aligning to allow us to do this mission.

Jim Green: That's right. This is a great opportunity to, to really understand this, this hidden idea of how the solar system came about by studying these small bodies. Well, how long does the total mission take?

Hal Levison: So the mission is roughly 12 years. Our last encounter is with my favorite object, which is a near-equal mass binary. So these are two 100-kilometer size things. They're almost the same size, in nearly circular orbit around one another. Fascinating. I think they're leftovers from the formation of the planets, the original formation of the planets. That is on March 3, 2033.

Jim Green: Wow. (laughs) That's fantastic. Well, what are the instruments that you're taking on Lucy?

Hal Levison: So Lucy has three basic scientific instruments. There's a narrow field panchromatic camera called L’LORRI. We put a an L apostrophe before all our instrument names for Lucy.

Jim Green: (laughs) I see.

Hal Levison: So it’s L’LORRI that came out of APL that's going to do our high resolution imaging for crater counts and looking at geology. And it's going to do our satellite searches and look for rings and various things like that. We have a thermal infrared instrument spectrograph, which is out of Arizona State University. Right? It is going to allow us to measure the temperature of the object over various locations, that will tell us how the rocks on the surface heat and cool, which will tell us something about the structure of the surface, whether it's sandy or whether it's rocky.

Hal Levison We have an instrument called L’Ralph, which is out of Goddard, which is actually two instruments and one. It's a color camera. And it's a near infrared spectrograph, imaging spectrograph, which is going to give us information about the chemical makeup of the surface. In addition to that, we're going to use our high-gain antenna to measure the mass of the objects as we go by, as they gravitational tug on the spacecraft, we can measure how massive they are through Doppler shift. And we have a navigation camera, which is a wide field panchromatic camera, which is going to give us its shape. So with the mass and the shape, we should be able to get a dense density, which is a very important diagnostic for figuring out how these things formed.

Jim Green: So as you said, many of these Trojans are different in their spectral appearance. So are we visiting each and every one of the variations of the Trojans?

Hal Levison: Yes, as far as we can tell, right? I mean, the mission was designed to do that. Now a lot of this is luck, but what we set out to do was to visit the extremes, right. So we have one object, which is our first Trojan that we encounter called Euripides, it's really cool object. And it's very gray. So we're going to that one. And then we looked for an object of similar size and a similar orbit as Euripides, but very red.

Hal Levison: And what we tried to do is make them so similar in every other way, that any differences that we see is due to the composition of their surfaces. And so we're going to be able to do a direct comparison between a gray and red object. And then we just filled in what we could do, and the objects we could find. You know, once we did that, we saw we saw a whole spectrum of objects that fit the diversity that we needed

Jim Green: So Hal, what's been the greatest challenge in putting this mission together?

Hal Levison: Well, I mean, it's rocket science.

Jim Green: (laughs)

Hal Levison: There's been many challenges. Some we expected, some we didn't. Lucy, another record that we're breaking with Lucy is we're going further from the Sun than any solar powered spacecraft in history.

Jim Green: Oooh.

Hal Levison: So we have very large solar arrays. And we're in order to save mass for we used, I wouldn't say the new design, but it's certainly never been used on deep space missions before. And we had to scale them up, because they're big. And so typically, these things are two, three meters in diameter. Ours is 7.3 meters in diameter. Scaling those up turned out to be a real challenge.

Jim Green: Well, you know, I just say, making these solar arrays very large, that's one thing. But you've got the other problem of folding them up and how you get them into a fairing to launch and then bringing them out and fully extending them.

Hal Levison:  Yes. And then there's the challenge: They have to be lightweight.

Jim Green: Right.

Hal Levison: So these things have fold up and unfold like oriental fans. And although the solar cells are, are not made out of cloth, the entire supporting structure is made out of cloth.

Hal Levison: I encourage your listeners to go online and see some videos of our arrays. They are really amazing. And it makes the spacecraft really large. Lucy from wingtip to wingtip is about 50 feet.

Jim Green: Wow, okay.

Hal Levison So it’s big. most of it is solar arrays.

Jim Green: Rocket science at its best.

Hal Levison Rocket science at its best. So, we've been in contact with Donald Johanson the discoverer of the Lucy fossil, through this whole thing, which has been, he's a fascinating guy.

Jim Green: Yes, he is.

Hal Levison: But he said something to me, I think, is insightful. He said, what makes human beings human beings is our ability to communicate and collaborate, to be able to do more than an individual person or creature can do. That's what makes us human. And while he's so into what we're doing here, is this is sort of the ultimate example of doing that. Going to space and building a spacecraft. Right? It really is rocket science.

Jim Green: Really exciting. Well, Hal, I always like to ask my guests to tell me that event or person, place or thing that got them so excited about being the scientists they are today. And I call that event a gravity assist. So, Hal, what was your gravity assist?

Hal Levison: I would say there were two events, right. Like I said, I've always been interested in where we came from. What got me interested in the astronomical side of things, was, you know, I grew up in the 70s. And actually, at the time, we were putting a lot of money in the public schools for teaching science and that kind of thing. And my high school had a planetarium, with a planetarium director, his name was Scott Negley. And I, when I showed up at high school, I took a little class from him and got hooked. I spent my high school years working in the planetarium, going out teaching, teaching elementary school kids and things like that.

Hal Levison: So that was also combined with, what NASA was doing at that time. That was the time of Pioneer and Viking and Voyager. So a lot was going on, the initial reconnaissance of the outer solar system, for example, that got me hooked.

Hal Levison: I remember, in particular, the Pioneer plaque.

Jim Green: Yeah!

Hal Levison: Really inspired me, right. There's a Plaque on pioneer, that sort of a message to aliens that can pick it up some time. But really, it made me understand that we’re really part of the galaxy, we really are part of the universe, right? We are part of the solar system, this idea, most people sit around and say, “Well, here's us, and then there's space, right, and space is separate from us.”

Hal Levison: And it's not true, we are embedded in it, We are part of it. And that's kind of a lesson that these kinds of plaques and things send to people and indeed, Lucy has a plaque on it.

Jim Green: Ah!

Hal Levison: It’s different, because Lucy will end its life in orbit around the Sun. Our calculation showed, if no one goes and picks it up, it'll spend almost a million years just orbiting between the Earth and Jupiter. And so what we did is we put a plaque on Lucy, with messages to our descendants, rather than messages to alien civilizations. So we've asked some cultural leaders within our community to contribute quotes that are on the plaque. And the plaque was put on the spacecraft a few weeks ago, and we're gonna launch it to the, to the planets.

Jim Green: Wow, that's fantastic. Indeed, I remember the Pioneer 10 and 11 plaques and, and that they were made, very simply showing here are the planets and here's where the spacecraft came from. And here's a man and a woman and the size of the spacecraft next to it, some really elementary images that helped understand the origin of our first two spacecraft that are leaving the solar system. Well, Hal, thanks so much for joining me and discussing your fantastic career and I wish you the best and the launch of Lucy.

Hal Levison: It's going to be an exciting day. And a beautiful launch because it's a nighttime launch. So it's going to be really beautiful to watch.

Jim Green: Well, join me next time as we continue our journey to look under the hood at NASA and see how we do what we do, I'm Jim Green, and this is your Gravity Assist.

Lead producer: Elizabeth Landau
Audio engineer: Manny Cooper
Last Updated: Oct 8, 2021
Editor: Gary Daines

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Odp: [NASA Gravity Assist] : Season 5
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