Natalya Bailey: Rocket Engines and Electric Spacecraft Propulsion | Lex Fridman Podcast #157

1. 0:00 – 1:46

   Introduction

   1. LFLex Fridman0:00

      The following is a conversation with Natalia Bailey, a rocket scientist and spacecraft propulsion engineer previously at MIT, and now the founder and CTO of Axion Systems, specializing in efficient space propulsion engines for satellites and spacecraft. So, these are not the engines that get us from the ground on Earth out to space, but rather the engines that move us around in space once we get out there. Quick mention of our sponsors: Munk Pack low-carb snacks; Four Sigmatic mushroom coffee; Blinkist, an app that summarizes books; and Sunbasket, meal delivery service. So, the choice is snacks, caffeine, knowledge, or a delicious meal. Choose wisely, my friends. And if you wish, click the sponsor links below to get a discount and to support this podcast. As a side note, let me say something about Natalia's story. She has talked about how when she was young, she would often look up at the stars and dream of alien intelligences that one day we could communicate with. This moment of childlike cosmic curiosity is at the core of my own interest in space, in extraterrestrial life, and in general, in artificial intelligence, science, and engineering. Amid the meetings and the papers and the career rat race and all the awards, let's not let ourselves lose that childlike wonder. Sadly, we're on Earth for only a very short time, so let's have fun solving some of the biggest puzzles in the universe while we're here. If you enjoy this thing, subscribe on YouTube, review it on Apple Podcasts, follow on Spotify, support on Patreon, or connect with me on Twitter @lexfridman. And now, here's my conversation with Natalia Bailey.

2. 1:46 – 5:47

   Intelligent life in the universe

   1. LFLex Fridman1:46

      You said that you spent your whole life dreaming about space, and also pondering the big existential question of whether there is or isn't intelligent life, intelligent alien civilizations out there. So, what do you think? Do you think there's life out there? Intelligent life?

   2. NBNatalya Bailey2:03

      Intelligent life. That's trickier. I- I think looking at, you know, the- the likelihood of a self-replicating organism, given how much time the universe has exi- existed, and how many stars with planets, I think it's likely that there's other life. Intelligent life, I'm hopeful. You know, I'm a little discouraged that we haven't yet been in touch.

   3. LFLex Fridman2:34

      Uh, allegedly.

   4. NBNatalya Bailey2:35

      I remain hopeful.

   5. LFLex Fridman2:35

      I mean, d- it's also-

   6. NBNatalya Bailey2:37

      On the- in- in our dimensions-

   7. LFLex Fridman2:38

      Right.

   8. NBNatalya Bailey2:39

      ... and so on, yeah.

   9. LFLex Fridman2:39

      It's also possible that, uh, they have been in touch and we just haven't ... we're too dumb to realize they're communicating with us, in whichever is the- it's the S- Carl Sagan idea that they may be communicating at a timescale that's totally different.

   10. NBNatalya Bailey2:54

       Yeah.

   11. LFLex Fridman2:54

       Like, their- their signals are on a totally different timescale, or on a, like, a totally different kind of medium of communication. It could be- it could be our own- it could be the birth of, like, human beings, like, that th- the- whatever the magic that makes us who we are, the collective intelligence thing, that could be aliens themselves. That could be the medium of communication. Like, the nature of our consciousness and intelligence itself is the medium of communication. And when-

   12. NBNatalya Bailey3:24

       And, like, being able to ask the questions themselves.

   13. LFLex Fridman3:28

       Right.

   14. NBNatalya Bailey3:29

       I've never thought of it that way.

   15. LFLex Fridman3:30

       Like, actually, yeah. Asking the question-

   16. NBNatalya Bailey3:32

       Yeah. (laughs)

   17. LFLex Fridman3:32

       ... whether aliens exist might be the very medium by which they communicate. It's like they- they send questions as opposed to answers.

   18. NBNatalya Bailey3:38

       So, some- this, like, collective emergent behavior is- is the signal?

   19. LFLex Fridman3:44

       Is the signal, yeah. (laughs) So, the ob-

   20. NBNatalya Bailey3:47

       That's interesting, yeah.

   21. LFLex Fridman3:48

       'Cause maybe that's how we would communicate with ... If you think about it, if we were way, way, way smarter, like a thousand years from now, we somehow survive, like how would we actually communicate? In a way, that's like, if we broadcast the signal, you know, and then it could somehow, like, percolate throughout the universe. Like, that signal having impact on-

   22. NBNatalya Bailey4:10

       Multiverse.

   23. LFLex Fridman4:11

       Multiverse, of course. (laughs) Uh, that would have a signal in- uh, uh, an effect on the most possi- the most-

   24. NBNatalya Bailey4:19

       Mm-hmm.

   25. LFLex Fridman4:19

       The highest number of possible civilizations. What would that signal be? It might not be, like, sending a few, like, stupid little "Hello, world" messages. It might be something more impactful. Where ... It's almost, like, impactful in a way where they don't have to have the capability to hear it. It, like, forces the message to have an impact.

   26. NBNatalya Bailey4:42

       Right. My (laughs) train of thought has never gone- gone there.

   27. LFLex Fridman4:46

       Good.

   28. NBNatalya Bailey4:46

       But I like it.

   29. LFLex Fridman4:47

       (laughs)

   30. NBNatalya Bailey4:48

       And also somewhere in there, I think it's implied that something travels faster than the speed of light, which I'm also really hopeful for.
3. 5:47 – 7:52

   Life in our solar system

   1. NBNatalya Bailey5:47

   2. LFLex Fridman5:47

      Do you think there's life on Mars? Uh, like, uh, no longer ... well, already living but- uh, currently living, but also no longer living? Like, that we might be able to find life. There's- there's- some people suspect basic mo- microbial life.

   3. NBNatalya Bailey6:03

      I'm not so sure about in our own solar system, and, and I do think it might be hard to untangle if we somehow contaminated other things as well.

   4. LFLex Fridman6:14

      Yeah.

   5. NBNatalya Bailey6:15

      Uh, so I'm not sure about this close to home.

   6. LFLex Fridman6:19

      That would be really exciting.

   7. NBNatalya Bailey6:20

      Yes.

   8. LFLex Fridman6:21

      Like, do you think about the Drake equation much, of like-

   9. NBNatalya Bailey6:23

      That was what, yeah, what got me-

   10. LFLex Fridman6:26

       (laughs)

   11. NBNatalya Bailey6:26

       ... (laughs) into all of this, yeah.

   12. LFLex Fridman6:28

       Yeah, 'cause, uh, one of the questions is how hard is it for life to start on a habitable planet. Like, if you have a lot of the basic conditions, not exactly like Earth, but basic Earth-like conditions, how hard is it for life to start? And if you find life on Mars or find life on Europa, that means it's way easier. That's a good thing to confirm that if you have a habitable planet, then there's going to be life. And that, like, immediately, that's g- that would be super exciting 'cause that means there's like trillions of planets-

   13. NBNatalya Bailey7:02

       Yeah.

   14. LFLex Fridman7:02

       ... with basic life out there.

   15. NBNatalya Bailey7:04

       Though, of all the planets in our solar system, Earth is clearly the most habitable, so, uh, I would not be discouraged if we didn't find it on another planet-

   16. LFLex Fridman7:15

       Sure.

   17. NBNatalya Bailey7:15

       ... in our solar system.

   18. LFLex Fridman7:17

       True, and again, that life could look very different. It's habitable-

   19. NBNatalya Bailey7:19

       Yeah.

   20. LFLex Fridman7:19

       ... for Earth-like life.

   21. NBNatalya Bailey7:20

       Right.

   22. LFLex Fridman7:21

       But it could be, uh, totally different. I still think that trees are quite possibly more intelligent than humans, but their intelligence is carried out over a timescale that we're just not able to appreciate.

   23. NBNatalya Bailey7:33

       Huh.

   24. LFLex Fridman7:33

       Like, they might be running the entirety of human civilization, and we're just, like, too dumb-

   25. NBNatalya Bailey7:37

       (laughs)

   26. LFLex Fridman7:37

       ... to realize that they're, they're the smart ones.

   27. NBNatalya Bailey7:40

       Maybe that's the alien message. It's in the trees.

   28. LFLex Fridman7:44

       It's in the tr- (laughs) in the trees.

   29. NBNatalya Bailey7:47

       (laughs)

   30. LFLex Fridman7:47

       Uh, yeah, it's not in the, uh, monolith in the Utah desert, it's in the trees.
4. 7:52 – 11:26

   Humans on Mars

   1. LFLex Fridman7:52

      So, le- let's go to space exploration. Uh, how do you think we get humans to Mars?

   2. NBNatalya Bailey7:57

      I, I think SpaceX and, and Elon Musk will be the ones that get the first human setting foot on Mars, uh, and probably not that long from now, from us having this conversation. You know, maybe we'll inflate his timeline a little bit, but I tend to believe, um, the goals he sets. So, I think that will happen relatively soon. Um, as far as, you know, when and what it will take to get humans living there in a more permanent way, um, you know, I have a glib answer which is, you know, when we can invent a, a time machine to go back to the early Cold War, and instead of uniting around sending people to the moon, um, we pick Mars as the destination. Uh, so really, I, you know, I, I say that because there's nothing truly scientifically or technologically impossible about doing that soon. Uh, it's more, you know, politically and financially and, and those are the obstacles, I think, to that.

   3. LFLex Fridman9:04

      Well, I wonder of when you colonize with, you know, more than, say, five people on Mars, you have to start thinking about the kind of, uh, r- like, rules you have on Mars.

   4. NBNatalya Bailey9:16

      Yeah.

   5. LFLex Fridman9:16

      And speaking of the Cold War, who gets to own the land? You know, you start planting flags and you start to make decisions. And, uh, (laughs) like SpaceX has this ni- it's probably a little bit trolly, but they have this nice paragraph in their contracts where it's like, it's, it talks about (laughs) that, uh, like human, uh, governments on Earth or Earth governments have no, uh, jurisdiction on Mars. Like, the rules, the martians get to define their own rules.

   6. NBNatalya Bailey9:50

      (laughs) Sure.

   7. LFLex Fridman9:50

      And it sounds very much like, uh, (laughs) like the Founding Fathers for this country. That's the kind of language. Uh, it's interesting that that's, that that's in there and it makes you think, perhaps that needs to be leveraged, like you have to be very clever about leveraging that to, uh, to create a little bit of a Cold War feeling. It seems like we're, w- we humans need a little bit of a competition. Do you think that's necessary to s- succeed and, um, to get the, the necessary investment? Or can the pure pursuit of science be enough?

   8. NBNatalya Bailey10:28

      No, I think we're seeing right now the pure pursuit of science, I mean, that results in pretty tiny budgets for exploration. Um, there has to be some disaster, impending doom (laughs) um, to get us onto another planet in a permanent way. I don't know... Financially, I just don't know if the private sector can support that, and, but I don't n- I, you know, I don't wish that there is some catastrophe coming our way that, that spurs us to do that.

   9. LFLex Fridman11:03

      Yeah, it's un- I'm unsure what the business model is for colonizing Mars.

   10. NBNatalya Bailey11:08

       Yeah, exactly.

   11. LFLex Fridman11:09

       Yeah, like there is for, we'll talk about satellites. There's probably a lot of business models around satellites, but there's not enough short term business. I guess that's how business works. Like, you should have a, (laughs) you should have a path to making money in like the next 10 years.

   12. NBNatalya Bailey11:25

       Well, and

5. 11:26 – 12:20

   Robots vs human in space exploration

   1. NBNatalya Bailey11:26

      m- maybe even more broadly and, and looping back to something we, we said earlier, I don't know that getting humans off this planet and, you know, spreading (laughs) um, like bacteria is what we're supposed to be doing in the first place. So-

   2. LFLex Fridman11:45

      Yeah.

   3. NBNatalya Bailey11:46

      ... maybe we can go but should we? And, and I'm probably a, uh, unusual person for thinking that in my industry because humans want to explore, but I almost wonder, you know, are we putting unnecessary obstacles, like, uh, or very finicky biological things in the way of some more robotic or-... you know, more silicon-based exploration. Um, and, yeah, do we need to colonize and spread? I'm not sure.

6. 12:20 – 16:25

   AI in space

   1. NBNatalya Bailey12:20

   2. LFLex Fridman12:20

      What do you think is the role of AI in space? Do you, uh, in your work, again, we'll talk about it, but do, do you see more and more of the space vehicles, spacecraft being run by artificial intelligence systems? More than just, like, the flight control, but, like, the management?

   3. NBNatalya Bailey12:41

      Yeah, I don't have a lot of color to the dreams I have about way in the future in, in AI, but I do think that removing... You know, it's hard for humans to even make a trip to Mars, much less go anywhere farther than that. And I think we'll have, you know, more, uh, this, again, I'm probably unusual in, in having these thoughts, but perhaps be able to, to generate more knowledge and understand more if we stop trying to send humans and instead, you know, I don't know if we're talking about AI, um, in a truly, you know, artificial intelligence way or AI as, as we kind of use it today. Um, but maybe sending a petri dish or two of, like, stem cells and some robotic handlers instead if we still need to send our DNA because we're really stuck on that. Um, but if not, you know, maybe not even that petri dish. Um, so I see, I think what I'm saying is, you know, I see a, a much bigger role in the future of AI for space exploration.

   4. LFLex Fridman13:47

      It's kind of sad to think that, uh, I mean, I'm sure we'll eventually send a spacecraft with, uh, efficient propulsion, like some of the stuff you work on out that travels just really far with some robots on it and with some, with some DNA in a petri dish.

   5. NBNatalya Bailey14:05

      Yeah.

   6. LFLex Fridman14:05

      And then human civilization destroys itself, and then there'll just be this floating spacecraft that eventually gets somewhere or not.

   7. NBNatalya Bailey14:13

      Yeah.

   8. LFLex Fridman14:14

      That's a sad thought, like this lonely spacecraft just kind of traveling through space and humans are all dead.

   9. NBNatalya Bailey14:20

      Well, it depends-

   10. LFLex Fridman14:21

       That's a possible future.

   11. NBNatalya Bailey14:22

       ... it depends on what the, what the goal is, right? (laughs)

   12. LFLex Fridman14:26

       (laughs) I don't-

   13. NBNatalya Bailey14:27

       Another way to look at it is-

   14. LFLex Fridman14:28

       I don't know what the goal is. Yeah.

   15. NBNatalya Bailey14:29

       ... we've preserved, it's like a little time capsule of knowledge, DNA, you know, that we've-

   16. LFLex Fridman14:34

       Mm-hmm.

   17. NBNatalya Bailey14:34

       ... that will outlive us. So-

   18. LFLex Fridman14:36

       Well, that's beautiful.

   19. NBNatalya Bailey14:37

       Yeah. (laughs)

   20. LFLex Fridman14:38

       (laughs) Uh-

   21. NBNatalya Bailey14:39

       It's how I sleep at night. (laughs)

   22. LFLex Fridman14:41

       So, you also mentioned that you wanted to be an astronaut.

   23. NBNatalya Bailey14:43

       Yes.

   24. LFLex Fridman14:45

       So, even though you said you're unusual in thinking, like, it's nice here on earth and that we might want to be sending robots up there, you wanted to be a human that goes out there. Would you like to one day travel to Mars? You know, if it's, if, if it becomes sort of more open to civilian travel and that kind of thing. Like, are you, uh, like vacation-wise, like if we're talk- if we're talking vacations, would you like to vacation on earth or vacation on Mars?

   25. NBNatalya Bailey15:15

       I wish that I had a better answer, but no. I wanted to be an astronaut because I, first of all, I like working in labs and doing experiments and, um, I wanted to go to, like, the coolest lab, the ISS.

   26. LFLex Fridman15:33

       (laughs) Yeah.

   27. NBNatalya Bailey15:34

       Um, and do some experiments there. Uh, that's being decommissioned, which is sad. But, you know, there will be others, I'm sure. Um-

   28. LFLex Fridman15:43

       The ISS is being decommissioned?

   29. NBNatalya Bailey15:44

       Yes. I think by 2025 it's not going to be in use anymore. But I think, um, there are other, there are private companies that are going to be putting up stations and things.

   30. LFLex Fridman15:55

       So, it's primarily like a research lab essentially.
7. 16:25 – 21:42

   How rocket engines work

   1. LFLex Fridman16:26

      Okay, let's talk rockets. Uh, how does a rocket engine work or any kind of engine that can get us to space or float around in space?

   2. NBNatalya Bailey16:36

      The basic principle is conservation of momentum. So, um, you throw stuff out the back of the engine and, oops, uh, and that pushes the rocket and the spacecraft in the other direction. So, uh, there are two main types of, of rocket propulsion. Um, the one people are more familiar with is chemical because it's loud and there's fire. Um, and that's what's used for launch and is more televised. So, um, in, in those types of systems, you usually have a f- a fuel and an oxidizer and, um, they react and combust and release stored chemical energy. Um, and, and that energy heats, um, heats the resultant gas and, and that's funneled out the back through a nozzle, uh, directed out the back and, and then that momentum exchange, um, pushes the spacecraft forward.

   3. LFLex Fridman17:32

      Is there an interesting difference between liquid and solid fuel in those contexts?

   4. NBNatalya Bailey17:36

      They're both lumped in the same. So, uh, chemical just means that the release of energy from, from those bonds essentially. So, a solid fuel works the same way. Uh, and the other main category is electric propulsion, so instead of chemical energy, you're using electrical energy, um, usually from, you know, batteries or solar panels. And, uh, in this case, the stuff you're pushing out the back, uh, would be charged particles. So, um, instead of combustion and heat, you, you end up with charged particles and you force them out the back of the spacecraft using either an electrostatic field or electromagnetic. Um, and, but it's the same momentum exchange and, and same idea stuff out the back and everything else goes forward.

   5. LFLex Fridman18:27

      Cool. So, those are the big two categories. What, what's the difference maybe in like (exhales sharply) the challenges of each, the use cases of each, and, uh, how they're used today? The physics of each, like-

   6. NBNatalya Bailey18:45

      Hmm.

   7. LFLex Fridman18:45

      ... and where they're used, all that kind of stuff. Anything interesting about the two categories that distinguishes them? Besides the, the chemical one being the big sexy flames and-

   8. NBNatalya Bailey18:56

      Yeah. (laughs) Fire.

   9. LFLex Fridman18:57

      ... fire. (laughs) Yeah.

   10. NBNatalya Bailey18:59

       Chemical is very well understood. Um, you know, uh, in its simplest form, it's like a firework, so it's been around since 400 BC or something like that. Um, so that... Even the big engines are quite well understood. I think, you know, one of the, one of the last gaps there is probably, um, what exactly are the products of combustion? Um, our modeling abilities kind of fall apart there, um, because it's hot and gases are moving. And, uh, you end up kind of, you know, having to venture into, um, lots of different interdisciplinary fields of science to try to solve that, and that's quite complex. But we have pretty good, um, models for some of the more like emergent behaviors of that system anyways. But that's, I think, one of the last unsolved pieces. Um, and really the, the n- kind of what people care about there is, is making it more fuel efficient. So, the chemical stuff, um, you can get a lot of, um, instantaneous thrust, but it's not very fuel efficient. It's much more fuel efficient to go with the electric type of propulsion. Um, so that's where people spend a lot of their time, um, is trying to make that more efficient in terms of thrust per unit of fuel. And then, um, there's always considerations like heating and cooling. It's very hot, which is good if it heats the gases but, you know, bad if it melts the rocket and, and things like that. So, there's always a lot of work on heating and cooling and, and the engine cycles and things like that. Um, and then on electric propulsion, I find it like much more refreshingly poorly understood.

   11. LFLex Fridman20:54

       (laughs)

   12. NBNatalya Bailey20:55

       Um-

   13. LFLex Fridman20:56

       Lots more mysteries.

   14. NBNatalya Bailey20:57

       Yeah. I think so. Uh, one of the classes I took in college spent... We spent 90% of the class on chemical propulsion, and then the last 10% on electric. And the professor said like, "We only sort of understand how it works, but it works kind of." And I was like, "That's-

   15. LFLex Fridman21:15

       That's what I'm gonna work on. (laughs)

   16. NBNatalya Bailey21:15

       "... that's interesting." Yeah. And, uh, you know, even, uh, an ion engine, which is probably one of the most straightforward because it's... it has just an... it's just an electrostatic engine. But it has this really awesome combination of like quantum mechanics and, um, material science and fluid dynamics and, uh, electrostatics and, and, um, it's just very intriguing to me. Um-

8. 21:42 – 26:05

   How ion engines work

   1. NBNatalya Bailey21:42

   2. LFLex Fridman21:42

      First of all, can you actually zoom out even more? Like, 'cause you mentioned ion propulsion-

   3. NBNatalya Bailey21:47

      Yeah.

   4. LFLex Fridman21:47

      ... engine is a subset of electric p-

   5. NBNatalya Bailey21:50

      Of the electric. Mm-hmm.

   6. LFLex Fridman21:51

      So like, maybe... Is there categories of electric engines and then we can zoom in on ion propulsion?

   7. NBNatalya Bailey21:55

      Yes. So... Sure. There's, um... The two most kind of conventional types that have been around since the '60s are ion engines and Hall thrusters. And ion engines are a little bit simpler because they don't use a magnetic field for generating thrust. Um, and then there are also, um, some other types of plasma engines but that don't fit into those two categories, so just kind of other plasma like, um, a VASIMR engine, which we could get into. Um, and then those are probably the main three categories that would be fun to talk about. Oh, and then, of course, the category, um, of engine that I work on, which is, um... has a lot of similarities to an ion engine but could be considered its own class called a colloid thruster.

   8. LFLex Fridman22:44

      Colloid. Cool. Okay. So, what is an ion propulsion, ion engine?

   9. NBNatalya Bailey22:48

      Uh... Okay. So, in an ion engine, you have an ionization chamber and you inject the propellant into that chamber. And this is usually, um, a neutral gas like xenon or argon. Uh, so you inject that into the chamber and you also inject, um, a, a stream of really hot high-energy electrons. And everything's just moving around, um, very randomly in there. And the, the whole goal is to have, um, one of those electrons collide with one of those neutral atoms and turn it into an ion. So, kick off a secondary electron and now you have, uh-

   10. LFLex Fridman23:29

       Plasma.

   11. NBNatalya Bailey23:30

       Yes.

   12. LFLex Fridman23:30

       Okay.

   13. NBNatalya Bailey23:31

       And now you have (laughs) ... Um, uh, and now you have a charged, you know, xenon or argon ion and, and more electrons and so on. Um, and then, uh, some fraction of those ions will happen to make it to this downstream, um, electric field that we set up between two grids with holes in them.

   14. LFLex Fridman23:53

       Mm-hmm.

   15. NBNatalya Bailey23:54

       And, you know, in terms of area, the same amount of those ions also makes... runs into the walls and lose their charge and, um, that's where some of the inefficiencies come in. But the very lucky few make it to those holes in, in that grid and they're, um, two grids actually, and you apply a, a voltage differential between them and, and that sets up an electric field. And a charged particle in an electric field, uh, creates a force. Uh, and so those ions are accelerated out the back of the engine and the reaction force is, um, is what pushes the spacecraft forward. Um-... if you're, you know, following along and tallying these charges, now we've just sent a positive beam of ions out the back of the spacecraft, um, and, and for our purposes here, the spacecraft is neutral. So eventually, um, those ions will come back and hit the spacecraft because it's a positive beam. So you also have to have an external cathode, um, producer of electrons outside the engine that pumps electrons into that beam and neutralizes that. So now it's net neutral everywhere and it won't come back to the spacecraft. So that's, that's an ion engine.

   16. LFLex Fridman25:07

       What temperature are we talking about here? So in terms of like the, the chemical-based engines, those are super hot. Uh, you mentioned plasma here. How hot does this thing get?

   17. NBNatalya Bailey25:18

       Um-

   18. LFLex Fridman25:20

       I mean, is that an interesting thing to talk about in a sense that... Is that a-

   19. NBNatalya Bailey25:23

       Yeah.

   20. LFLex Fridman25:23

       ... interesting distinction or is heat... I mean, it's all gonna be hot.

   21. NBNatalya Bailey25:28

       No, so it's important, uh, especially for some of these smaller satellites people are into launching these days. So the, it, it's important because you have the plasma, but also those high energy electrons are hot, and, um, if you have a lot of those that are going into the walls, you do have to care about the temperature. So, um, I... Uh, I'm having trouble remembering off the top of my head. I think they're at like 100 electronvolts in terms of the electron energy, and then I'd have to f- remember how to convert that into kelvin.

   22. LFLex Fridman26:00

       Can you stick your hand in it? Is that, not room temperature?

   23. NBNatalya Bailey26:03

       No, not recommended. (laughs) Yeah.

   24. LFLex Fridman26:04

       Okay.

9. 26:05 – 35:03

   How colloid engines work

   1. LFLex Fridman26:05

      So what's a colloid engine?

   2. NBNatalya Bailey26:07

      So the same rocket people that, um, came up with, with these ideas for electric propulsion, um, probably in the middle of, of last century, uh, also realized that there's one more place to get charged particles from, um, if you're going to be using electric propulsion. So you can take a gas and you can ionize it, but there are also some liquids, particularly ionic liquids, which is what we use, that you also can, um, use as a source of ions. And if you have ions and you put them in a field, you generate a force. So they recognized that, but, um, part of being able to leverage that technique is being able to m- kind of manipulate those liquids on a scale of nanometers or, or, you know-

   3. LFLex Fridman27:00

      Hm.

   4. NBNatalya Bailey27:00

      ... very few microns. So, you know, the diameter of a human hair or something like that.

   5. LFLex Fridman27:05

      Oh.

   6. NBNatalya Bailey27:05

      And in the '50s, there was no way to do that, so they wrote about it in some books and then it kind of died for a little bit. And then with, um, silicon, MEMS computer processors, and, and when foundry started becoming more ubiquitous, and my advisor, um, started at MIT, uh, kind of put those ideas back together and was like, "Hey, actually there's now a way to build this and bring this other technique to life." Um, and so the way da- the way that you actually get the, the ions out of those liquids, um, is you put the liquid in a, in, again, a strong electric field, and the electric field stresses the liquid, and you keep increasing the field, and eventually the liquid will assume, uh, I'll go this way, a, a conical shape. Um, it's the, it's when the electric field pressure that's pulling on it exactly balances the liquid's own restoring force, which is its surface tension.

   7. LFLex Fridman28:05

      Mm-hmm. Cool.

   8. NBNatalya Bailey28:06

      So you have this balance and the liquid assumes a cone, um, when it's perfectly balanced like that. And at the tip of a cone, um, the radius of curvature goes to zero right at the tip.

   9. LFLex Fridman28:18

      Mm-hmm.

   10. NBNatalya Bailey28:18

       Um, and, uh, the radius, uh, sorry, the electric field, um, right at the tip of a sharp object would go to infinity, uh, 'cause it goes, um, uh, as one over the radius and, one over the radius squared, and instead of the electric field going to infinity and maybe like generating a wormhole or something, um, a jet of ions instead starts, you know, issuing from-

   11. LFLex Fridman28:44

       Mm-hmm.

   12. NBNatalya Bailey28:44

       ... the tip of, of that liquid. So the field becomes strong enough there that you can pull ions, um, out of the liquid.

   13. LFLex Fridman28:50

       Uh, what is the liquid we're talking about? What-

   14. NBNatalya Bailey28:52

       So, um-

   15. LFLex Fridman28:52

       ... or is it, there's a bunch of different ones?

   16. NBNatalya Bailey28:54

       You can do it with, um, with different types of liquids. It depends on, you know, how easily you can free ions from their neighbors and if it has enough surface tension so that you can build up a high enough electric field. But, um, what we use are called ionic liquids and they're really just positive. They're, uh, they're very similar to salts but they happen to be liquid over a really wide range of temperatures.

   17. LFLex Fridman29:19

       This sounds like really cool. (laughs)

   18. NBNatalya Bailey29:21

       It, yeah.

   19. LFLex Fridman29:22

       Okay. So how big is the c- uh, how big is the cone are we talk- uh, what, what's the size of this cone that generates the ions?

   20. NBNatalya Bailey29:27

       So if you have a cone that's emitting pure ions, um, the... I can't remember if it's the radius or diameter, but, um, that emission is happening from, of that cone is something like 20 nanometers.

   21. LFLex Fridman29:41

       Oh. (laughs) I was imagining-

   22. NBNatalya Bailey29:44

       So-

   23. LFLex Fridman29:44

       ... something slightly bigger. But so like this is, so this is tiny, tiny.

   24. NBNatalya Bailey29:48

       Yes.

   25. LFLex Fridman29:49

       Hence the only being able to do it recently.

   26. NBNatalya Bailey29:52

       Yeah. That's right.

   27. LFLex Fridman29:52

       So this is all controlled by a computer, I guess. Like, or like how, how-

   28. NBNatalya Bailey29:57

       (laughs) Yeah. Which one?

   29. LFLex Fridman29:58

       ... how do you control s- how do you create a cone that generates ions at a scale of nanometers exactly?

   30. NBNatalya Bailey30:04

       So the kind of main trick to making this work is that physically, we manufacture hundreds or thousands of sharp structures and then supply the liquid to the tips. So that does a few things. Um, it makes sure that we know where the ion beams are forming so we can put holes in the grid above them to let them actually leave instead of hitting, right?
10. 35:03 – 37:52

    Material science

    1. NBNatalya Bailey35:03

    2. LFLex Fridman35:03

       Okay. Zoom- zooming out a little bit on the physics, uh, apologize for the way too big of a question, but do you from either a s- ... You mentioned Accion is, you know, more sort of an engineering endeavor, right?

    3. NBNatalya Bailey35:16

       Mm-hmm.

    4. LFLex Fridman35:16

       But from a perspective of physics in general, science in general, or the side of engineering, what do you think is the most, to you, like, beautiful and captivating and inspiring idea in this space?

    5. NBNatalya Bailey35:30

       In this space, and then I'm gonna zoom out a little bit more, but, um, in this space, I keep butting up against material science questions. So, I ... Over the past 10 years, I feel like every problem or interesting thing I, I want to work on, if you dig deep enough, you end up in material science land, uh, which I find kind of exciting and it makes me want to dig in more there, and, um, I was just ... You know, f- ... Even for our technology, when we have to move the propellant from the tank to the tip of the emitters, we rely a lot on capillary action and you're getting into wetting and surface energies and-

    6. LFLex Fridman36:15

       At a scale of, like, nano scale?

    7. NBNatalya Bailey36:18

       Yeah. Yeah, I mean, you're ... It's, uh, all ... If you look further, it's quantum too, but it, it all is ... You know, I would-

    8. LFLex Fridman36:25

       Wait, capillary action (laughs) at the quantum level? (laughs)

    9. NBNatalya Bailey36:27

       Yeah. So I would ... I, I kind-

    10. LFLex Fridman36:30

        Oh, that's so cool.

    11. NBNatalya Bailey36:30

        It all comes back to me-

    12. LFLex Fridman36:32

        (laughs)

    13. NBNatalya Bailey36:32

        ... to, you know, material science. (laughs) there's so much-

    14. LFLex Fridman36:34

        Yeah.

    15. NBNatalya Bailey36:34

        ... we don't understand at these sizes, um, and I, I find that, um, inspiring and exciting, um, and then more broadly-... you know, I remember when I learned that the same equation that describes flow over an airfoil is used to price options, the Black-Scholes equation, and I was like, "Pfff." And it's, you know, just a partial differential equation, but that kind of connectedness of the univer- you know, uh, oh, I don't want to use-

    16. LFLex Fridman37:08

        (laughs)

    17. NBNatalya Bailey37:08

        ... options pricing and the universe in the same...

    18. LFLex Fridman37:10

        (laughs)

    19. NBNatalya Bailey37:10

        But you know what I mean. This connectedness, I find really magical.

    20. LFLex Fridman37:15

        Yeah, the patterns that mathematics reveals-

    21. NBNatalya Bailey37:17

        Yes.

    22. LFLex Fridman37:17

        ... seems to echo in a bunch of different places.

    23. NBNatalya Bailey37:20

        Yes.

    24. LFLex Fridman37:21

        Yeah, there's just weirdness. It's like it really makes you think, I think we're definitely living in a simulation. Like whoever-

    25. NBNatalya Bailey37:28

        (laughs)

    26. LFLex Fridman37:28

        ... whoever programmed it-

    27. NBNatalya Bailey37:29

        I like that that's your conclusion.

    28. LFLex Fridman37:30

        ... is using, (laughs) I know, is th- using, like, shortcuts to program it. Like, they didn't, they just copy and pasted some code for the different parts.

    29. NBNatalya Bailey37:38

        (laughs) Yeah.

    30. LFLex Fridman37:38

        It just-
11. 37:52 – 42:51

    Nuclear powered rocket engines

    1. LFLex Fridman37:52

       in terms of using, uh, Colloid engines, what's, what's an interesting difference between a propulsion of a rocket from earth once you're standing on the ground to orbit and then the kind of propulsion necessary for once you get out to orbit or to, to like deep space to, to m- move around?

    2. NBNatalya Bailey38:14

       Yes. The reason you can't use an engine like mine to get off the ground is, you know, the thrust it generates is, instantaneous thrust is very small, but if you, if you have the time and, and can accumulate that acceleration, you can still reach speeds that are, um, very interesting for exploration and, and even for missions with humans on them. Um, a- an interesting direction I think we need to go as, as humans exploring space is, um, the power supplies for electric propulsion are, are limiting us in that, um, you know, solar panels are really inefficient and, and bulky. And batteries, I don't know when anybody's ever gonna, um, improve battery technology. I know a lot of people that work on that. Um, and nuclear power, um, you, we could have a lot more powerful electric propulsion systems, so they would be extremely fuel efficient, but more instantaneous thrust to do more interesting missions, um, if we could start launching more nuclear systems. But-

    3. LFLex Fridman39:25

       Oh, so like s- so something that's powered, nuclear powered, if that's the right way to say it-

    4. NBNatalya Bailey39:31

       Yeah.

    5. LFLex Fridman39:31

       ... that ... But is in a small enough container that could be launched?

    6. NBNatalya Bailey39:36

       Yeah. So, um, I mean, uh, as a world, we do launch, um, spacecraft with nuclear power systems on board. But size is, is one consideration. It hasn't been a big focus, so the, the reactors and the heaters and everything are bulky and so they're really only suitable for some of the much bigger interplanetary stuff. Um, so that's one issue, but then it's a whole, like, rat's nest of political stuff as well.

    7. LFLex Fridman40:06

       I, I heard, uh, I think Elon describe or somebody, but I think, I think it was Elon that described the, uh, EVTOL, like electrical-

    8. NBNatalya Bailey40:15

       Mm-hmm.

    9. LFLex Fridman40:15

       ... vertical takeoff and landing vehicles. So basically saying rockets ... Um, obviously Elon is interested in electric vehicles, right? But he said that rockets can't, uh, in the, in the near term, it doesn't make sense for them to be electric. Uh, what ... Do you see a world with the rockets that we use to get into orbit are also electric based?

    10. NBNatalya Bailey40:40

        Uh, it's possible. You can produce the thrust levels you need, but you need this, uh, a much bigger power supply and, and-

    11. LFLex Fridman40:47

        Like nuclear.

    12. NBNatalya Bailey40:47

        ... I think that would be nuclear. And the only way people have been able to launch them at all is that they're in a, you know, 100 times redundancy safe mode while they're being launched and they're not turned on until they're farther off. So if you were to actually try to use it on launch, uh, I think a lot of people would still have an issue with that. But someday.

    13. LFLex Fridman41:08

        It's a- it's an interesting concept, nuclear. It seems like people, like everybody that works on nuclear power has shown how safe it is as a source of energy.

    14. NBNatalya Bailey41:17

        I know, right?

    15. LFLex Fridman41:18

        And, uh, and yet we are s- seem to be, I mean, based on the history, based on the excellent HBO s- series-

    16. NBNatalya Bailey41:26

        (laughs)

    17. LFLex Fridman41:26

        ... I'm rushing with the Chernobyl, it seems like we have our r- risk estimation about this particular power source is, uh, drastically inaccurate. But that's-

    18. NBNatalya Bailey41:36

        Yeah.

    19. LFLex Fridman41:36

        That's a fascinating idea that we would use nuclear as a source for our vehicles.

    20. NBNatalya Bailey41:42

        Mm-hmm.

    21. LFLex Fridman41:42

        Uh, and not just in outer space. That's cool. I'm gonna have to look into that. That's super interesting.

    22. NBNatalya Bailey41:47

        Well, um, just last year, Trump eased up a little bit on the regulations and NASA and hopefully others are, are starting to pick up on the development. So now is a good time to look into it 'cause there's actually some movement.

    23. LFLex Fridman42:02

        Is that a hope for you to, to explore different energy sources that the entirety of the vehicle uses something like, uh, uh, like the, the entirety of the propulsion systems for all aspects of the vehicle's-

    24. NBNatalya Bailey42:15

        Mm-hmm.

    25. LFLex Fridman42:15

        ... life travel is the same or electric? Is it possible for it to be the same, like the Colloid engine being used for everything?

    26. NBNatalya Bailey42:24

        You could a- and you would have to do it in the same way we do different stages of rockets now where once you've used up an, an engine, um, or a stage, you let it go because there's really no point in holding onto it. So I wouldn't necessarily want to use the, the same engine for the whole thing, but the same technology I think would be interesting.

    27. LFLex Fridman42:45

        Okay, so it's possible. All right. But, uh, in terms-

    28. NBNatalya Bailey42:48

        Yeah. It comes down to the power source.

    29. LFLex Fridman42:49

        The power source. It's, that's really interesting.

12. 42:51 – 46:18

    Electric propulsion out in space

    1. LFLex Fridman42:51

       But for the current power sources and its current use cases, what's the use case for electric, like the, uh, the, the Colloid engine-... can you talk about where they're used today?

    2. NBNatalya Bailey43:01

       Sure. So chemical engines are still used, um, quite a bit once you're in orbit, but that's also where you might choose instead to use an electric system and what people do with them, and, and this includes, you know, the ion engines and hall thrusters and our engine, um, is basically any maneuvering you need to do once you're dropped off. Um, there's... Even if your only goal was to just stay in your orbit and not move for the life of your mission, you need propulsion to accomplish that, because the Earth's gravity field changes as you go around in orbit and pulls you out of your little box. Um, there are other perturbations, um, that, that can throw you off a bit. Um, and then, you know, most people want to do things a little bit more interesting, like, uh, maneuver to avoid being hit by space debris or, uh, perhaps lower their orbit to take a higher resolution image of something and then return. Um, at the end of your mission, uh, you're supposed to responsibly get rid of your satellite, whether that's, um, burning it up, but if you're in GEO, um, you want to push it higher into graveyard orbit. Um-

    3. LFLex Fridman44:17

       What's GEO and what's G- what's, uh, graveyard-

    4. NBNatalya Bailey44:19

       Um, so low earth orbit and then geosynchronous orbit or geostationary orbit.

    5. LFLex Fridman44:23

       And there's a graveyard? What's the graveyard?

    6. NBNatalya Bailey44:24

       Yeah. So those satellites are at, um, like 40,000 kilometers, so if they were to try to push their satellites, um, back down to burn up in the atmosphere, they would need, you know, even more propulsion than they've had for the whole lifetime of their mission. So instead, they push them higher, where it'll take, you know, a million years for it to naturally de-orbit. Um, so we're also cluttering that higher bit up as well, but it's not as pressing as, as LEO, which is low earth orbit, where more of these commercial missions are going now.

    7. LFLex Fridman44:56

       Well, so what... How hard is the collision avoidance problem there? You said some debris and stuff. So, like, how much propulsion is needed? Like, how much is, uh, the life of a satellite is just like, "Oh, crap." Trying, (laughs) trying to avoid, like, little bits down there?

    8. NBNatalya Bailey45:09

       Yeah. I think one of the recent, um, you know, rules of thumb I heard was per year some of these small satellites are doing, like, three collision avoidance maneuvers. Um, so that's-

    9. LFLex Fridman45:22

       Oh, it's not too bad.

    10. NBNatalya Bailey45:23

        ... that's not... Yeah.

    11. LFLex Fridman45:24

        Well-

    12. NBNatalya Bailey45:24

        But it's not zero, um, and it-

    13. LFLex Fridman45:26

        (sighs)

    14. NBNatalya Bailey45:26

        Yeah. It takes a lot of, um, planning and people on the ground and, you know, n- n- none of that really, I don't think, right now is autonomous.

    15. LFLex Fridman45:36

        Oh, that's not good. (sighs)

    16. NBNatalya Bailey45:37

        Yeah, and then we have a lot of folks taking advantage of, you know, Moore's Law and cheaper spacecraft, so they're launching them up without the ability to maneuver themselves and they're like, "Well, I don't know."

    17. LFLex Fridman45:47

        (sighs)

    18. NBNatalya Bailey45:47

        "Just don't hit me." (laughs)

    19. LFLex Fridman45:49

        And three times a year, that could be, become affordable if it's like... If it gets hit, maybe it won't be damaged kind of thing? That kind of logic?

    20. NBNatalya Bailey45:57

        Affordable in that instead of launching one satellite, they'll launch, you know, 20 small ones. Yeah.

    21. LFLex Fridman46:02

        Yeah.

    22. NBNatalya Bailey46:02

        So if one gets taken out-

    23. LFLex Fridman46:04

        Yeah.

    24. NBNatalya Bailey46:04

        ... that's okay, but the problem is that, you know, one good-sized satellite getting hit, um, that's like a ballistic event that turns into 10,000 pieces of debris that then-

    25. LFLex Fridman46:14

        All right.

    26. NBNatalya Bailey46:14

        ... are the things that go and hit the other satellites.

    27. LFLex Fridman46:17

        Other... Right.

    28. NBNatalya Bailey46:17

        Yeah.

    29. LFLex Fridman46:17

        So

13. 46:18 – 51:12

    Satellites

    1. LFLex Fridman46:18

       do you, do you see a world where, like, uh, in your sense, in your own work and just in the space industry in general, do you see that, that people are moving towards bigger satellites or smaller satellites? Is there going to be a mix? Like what's... And what are we talk- what, what does it mean for a satellite to be big and what's... And small? What size are we talking about?

    2. NBNatalya Bailey46:36

       So big... The space industry prior to, I don't know, 1990, you know, I guess the bulk of... The majority of satellites were the size of a school bus and-

    3. LFLex Fridman46:49

       (laughs) Wow.

    4. NBNatalya Bailey46:49

       ... cost a couple billion dollars. Um, and now, you know, our first launches were on, um, satellites the size of shoe boxes that were built by high school students. So (laughs) that's very different, you know, to give you the two ends of the spectrum. Um, big satellites will... I, I think they're here to stay, at least as far as I can see into the future, um, for things like broadcasting. Um, you want to be able to, you know, broadcast to as many people as possible. Um, they're... You also can't just go to small satellites, um, and say Moore's Law for things like optics. So if you have an, an aperture on your satellite, you know, that just, that doesn't follow Moore's Law. That's, that's different, so it's always going to be the size that it will be. You know, unless there's some new physics that comes out that I'm not aware of, um, but if you need a resolution and you're at an altitude, that kind of sets your... The size of your telescope. Um, but because of Moore's Law, we, we are able to do a lot more with smaller packages and, and with that, be- you know, comes more affordability and opening up access to space to more and more people.

    5. LFLex Fridman48:03

       Well, what's the smallest satellite you've seen go up there? Like what, what are the smallest kind? You said shoe boxes.

    6. NBNatalya Bailey48:09

       Yeah. So I think, you know, the smallest... They're, uh, smallest common form factor can fit a softball inside.

    7. LFLex Fridman48:16

       Wow.

    8. NBNatalya Bailey48:17

       Um, so it's 10 centimeters on each side.

    9. LFLex Fridman48:20

       So cool.

    10. NBNatalya Bailey48:21

        Um, but then there are some companies working on, um, you know, fractions of that even.

    11. LFLex Fridman48:26

        Okay.

    12. NBNatalya Bailey48:26

        And they're doing things like, um, IOT-type applications, so it's very low, you know, bandwidth, um, type things, but they're finding some niches for those.

    13. LFLex Fridman48:37

        Do you mean like there's a business... There's a thing to do with them?

    14. NBNatalya Bailey48:40

        Yes, either-

    15. LFLex Fridman48:41

        Like what do you do with a small satellite like that?

    16. NBNatalya Bailey48:43

        Um, you can, you know, track a ship going across the ocean as... Like, if you need to... If you're just pinging something, you know, you can handle that, that amount of data, um, and those latencies-

    17. LFLex Fridman48:55

        And so you have to-

    18. NBNatalya Bailey48:56

        ... and so on.

    19. LFLex Fridman48:56

        You have to have propulsion on that. You have to have a little engine.

    20. NBNatalya Bailey48:58

        No, those are just, you know, letting fall out of the sky, um-

    21. LFLex Fridman49:03

        Okay. (laughs)

    22. NBNatalya Bailey49:03

        Yeah.

    23. LFLex Fridman49:04

        But what, uh... So what kind of satellites would you equip a colloid engine on?

    24. NBNatalya Bailey49:09

        Anything that's bigger than probably about 20 kilograms, um, anything that needs to stay up for more than a year, or anything somebody spent more than, like, 100K to build are kind of the ways I would think about it.

    25. LFLex Fridman49:22

        That's a lot of use cases.

    26. NBNatalya Bailey49:23

        Yeah.

    27. LFLex Fridman49:23

        What's a sm- what's a small sat?Like, what-what category?

    28. NBNatalya Bailey49:26

        Small sat's actually very big. I think it's, like-

    29. LFLex Fridman49:29

        Okay.

    30. NBNatalya Bailey49:29

        ... 700 kilograms or ... Hitting my microphone.
14. 51:12 – 52:50

    Photo of Earth from the Moon

    1. NBNatalya Bailey51:12

    2. LFLex Fridman51:12

       Can I ask you a ridiculous question?

    3. NBNatalya Bailey51:14

       Yes.

    4. LFLex Fridman51:15

       So I've recently watched this documentary on Netflix about, uh, flat Earthers.

    5. NBNatalya Bailey51:21

       Mm-hmm.

    6. LFLex Fridman51:22

       That bel- you know, that people ... That believe in a flat earth. As some- (laughs) as somebody who develops propulsion systems for-for-for satellites and for spacecraft, what's, uh, to you, is the most convincing evidence that the earth is round?

    7. NBNatalya Bailey51:40

       Probably some of the photos taken from the moon.

    8. LFLex Fridman51:48

       Photos from the moon?

    9. NBNatalya Bailey51:49

       Yeah.

    10. LFLex Fridman51:49

        Okay, so it's not from the s- from the satellite space. You're like-

    11. NBNatalya Bailey51:53

        Yeah, I think seeing tho- that perspective ... I ... Maybe I'm just ... I'm answering too personally 'cause I really love those photos.

    12. LFLex Fridman52:02

        'Cause they're beautiful? Yeah.

    13. NBNatalya Bailey52:04

        I really like the ones that show the moon and, um, the lunar lander and they're taken a little bit farther back, so you see earth and first you're like, "Wow, that's tiny and we're insignificant," and that's kind of sad, but then you see this really cool thing, that we landed on another- (laughs)

    14. LFLex Fridman52:21

        Yeah.

    15. NBNatalya Bailey52:22

        ... you know, planetary body and you're like, "Oh, okay."

    16. LFLex Fridman52:24

        Can you actually see earth? I-d-d-I don't ... I don't know if I remember those-

    17. NBNatalya Bailey52:27

        Yeah, I'll send you ... I'll send you that picture.

    18. LFLex Fridman52:29

        'Cause I love the pictures or videos f- of just earth from more ... from orbit and so on.

    19. NBNatalya Bailey52:34

        Right, yeah.

    20. LFLex Fridman52:34

        Just like those ... That's really bea- ... That- that's like a perspective shifter. That's the pale blue dot, right? The- it probably appears tiny.

    21. NBNatalya Bailey52:41

        Yeah, and just that, you know, juxtaposition of the insignificance that-

    22. LFLex Fridman52:46

        You're in another-

    23. NBNatalya Bailey52:47

        ... we built this really cool thing. (laughs)

    24. LFLex Fridman52:49

        (laughs) Yeah, take the picture.

15. 52:50 – 55:12

    Humans on Mars

    1. LFLex Fridman52:50

    2. NBNatalya Bailey52:50

       Um, I just love that, yeah.

    3. LFLex Fridman52:50

       Ah, that'd be cool. I can't ... I personally love the idea of humans stepping on Mars. I'm such a sucker for the romantic notion of that and being able to take pictures from m- Mars, like selfies.

    4. NBNatalya Bailey53:01

       So you would go?

    5. LFLex Fridman53:03

       I ...

    6. NBNatalya Bailey53:04

       (laughs)

    7. LFLex Fridman53:05

       ... I, uh, yeah, I would be ... W-what did you say? You said you wouldn't be in the first 100.

    8. NBNatalya Bailey53:09

       Not in the first thousand.

    9. LFLex Fridman53:10

       Tha-thousand.

    10. NBNatalya Bailey53:11

        Yeah.

    11. LFLex Fridman53:11

        Which it's funny because to me that's-that's brave to be in the first million. I think when the Declaration of Independence was signed in the United States, there was, like, two million people. So I would like to show up when they're signing those documents.

    12. NBNatalya Bailey53:29

        Okay.

    13. LFLex Fridman53:29

        So maybe the two million. Like, what- what-

    14. NBNatalya Bailey53:31

        Oh, that's an interesting way to think of it. Okay.

    15. LFLex Fridman53:32

        'Cause like then we're like participating as citizenry and defining the direction.

    16. NBNatalya Bailey53:38

        Mm-hmm. So it's not the technical risk, you just don't want to show up somewhere that's like America before ... (laughs)

    17. LFLex Fridman53:47

        Yeah, because-

    18. NBNatalya Bailey53:48

        Before that.

    19. LFLex Fridman53:48

        It's ... Oh, I- I ... From a psychological perspective, it's just gonna be a stressful mess as- as people have studied, right? It's like ... It ... People ... Uh, most likely, the process of colonization, like, looks like basically a prison. Like, you're in an inc- ... A very tight, enclosed space with people and it's just a really stressful environment.

    20. NBNatalya Bailey54:13

        Mm-hmm.

    21. LFLex Fridman54:13

        You know, h- how do you select the kind of people that would go? And then there would be drama, there's always drama. And it's ... And I just want to show up when there's some rules. But I mean, you know, it depends. So I'm not worried about the health and the technical difficulties.

    22. NBNatalya Bailey54:25

        Yeah, interesting.

    23. LFLex Fridman54:26

        I'm more worried about the psychological difficulties. And also just not being able to Tweet. Like, what are you gonna ... How are you-

    24. NBNatalya Bailey54:33

        Yeah.

    25. LFLex Fridman54:33

        ... how can you ... There's no Netflix. So, yeah, maybe not in the first million but the first 100, uh, thousand. It's exciting to define the direction of a new ... Like, how often do we not just have a revolution to redefine our government as, you know, smaller countries-

    26. NBNatalya Bailey54:49

        Sure.

    27. LFLex Fridman54:49

        ... are still doing to this day.

    28. NBNatalya Bailey54:50

        Start over.

    29. LFLex Fridman54:51

        But literally start over from scratch. There's, uh, just our financial system, it could be, like, based on cryptocurrency. You could think about, like, how demo- ... You know, we have-we have now the technology that can enable pure democracy, for example, if we choose to do that.

    30. NBNatalya Bailey55:09

        Mm-hmm, yeah.
16. 55:12 – 1:03:07

    Propulsion without fuel

    1. LFLex Fridman55:12

       of things. So we talked about two, uh, different forms of propulsion which are super exciting. So the chemical-based, that's doing pretty well, and then the e- electric-based. Is, um ... Are there types of propulsion ...... that might sound like science fiction right now, but are actually within the reach of science in the next 10, 20, 30, 50 years, that you kind of think about? Or maybe even within the space of even just, like, (sighs) like even ion engines. Is there, like, breakthroughs that might 10X the thing? Like, really improve it?

    2. NBNatalya Bailey55:49

       So, you know, the real game changer would be propellantless propulsion, and so every couple of years you see a new, now a startup or, um, a researcher comes up with some contraption for producing thrust that didn't require... You know, we've been talking about conservation and momentum, mass times velocity out the back, um, mass times velocity forward-

    3. LFLex Fridman56:14

       'Cause there's usually a mass.

    4. NBNatalya Bailey56:14

       Yes.

    5. LFLex Fridman56:14

       That's what-

    6. NBNatalya Bailey56:15

       Exactly. And you have to, you know, carry that up with you or find it on an asteroid or harvest it from somewhere if you didn't bring it with you. So, not having to do that would be, you know, one of the ultimate game changers, um, and- and I, you know, unless there are new types of physics, um, I don't know how we do it, but it comes up often, so it's something I- I do think about, and, um, you know, the one, I think it's called the Casimir effect, um, if you can- if you have two plates and- and the space between them is on the order of these, like, the wavelength of these ephemeral vacuum particles that pop into and out of existence or something, um... I may be confusing multiple types of propellantless forces, but, um, that- that could be real and could be something that- that we use eventually. Um-

    7. LFLex Fridman57:11

       What would be the power source?

    8. NBNatalya Bailey57:13

       Yeah, the most recent engine like this that has- was just debunked this year, I think, in- in March or something, was called the EmDrive, and, um, supposedly you- you used a power source so, you know, batteries or solar panels to generate microwaves into this resonant cavity, and people claimed it produced thrust. So they- they went straight from this really loose concept to building a device and testing it, and they said, "We've measured thrust." And sure, on their thrust balance they saw thrust, and different researchers built it and tested it and got the same measurements, and so it was looking actually pretty good, um, no one could explain how it worked, but what they said was that, um, this, inside the cavity, um, the microwaves themselves didn't change but the speed of light changed inside the cavity, so relative to that, um, you know, there-

    9. LFLex Fridman58:07

       Wow.

    10. NBNatalya Bailey58:08

        ... momentum was conserved.

    11. LFLex Fridman58:09

        Okay.

    12. NBNatalya Bailey58:09

        Um, and I don't, you know, I, whatever. Um, but finally someone I think at NASA built the device, tested it, got the same thrust, then unhooked it, flipped it backwards and turned it on but got the same thrust in the same direction again, and so they're like, "This is just an interaction with the test setup or, you know, some-"

    13. LFLex Fridman58:29

        Got it.

    14. NBNatalya Bailey58:29

        "... the chamber," or something like that.

    15. LFLex Fridman58:30

        Well said.

    16. NBNatalya Bailey58:31

        So, um, thwarted again, um, but, you know, it would- it would be so wonderful for everybody if we could figure out how to do it, but I- I don't know.

    17. LFLex Fridman58:40

        That's an interesting twist on it, because that's more about efficient travel, long distance travel, right? That's not necessarily about speed. That's more about-

    18. NBNatalya Bailey58:50

        Sure.

    19. LFLex Fridman58:50

        ... enabling, like-

    20. NBNatalya Bailey58:51

        Yeah.

    21. LFLex Fridman58:52

        ... less-

    22. NBNatalya Bailey58:52

        So hook that up to the nuclear power supply-

    23. LFLex Fridman58:55

        Yeah.

    24. NBNatalya Bailey58:56

        ... there you go.

    25. LFLex Fridman58:56

        Okay.

    26. NBNatalya Bailey58:57

        (laughs) Yeah.

    27. LFLex Fridman58:58

        (laughs) But still, w- wha-

    28. NBNatalya Bailey58:59

        Yeah.

    29. LFLex Fridman58:59

        ... in terms of speed, in terms of trying to, so there- there's recently a s- already, I think, been debunked or close to being debunked, but the, uh, signal, a weird signal from, um, our nearby friends, nearby exoplanets from, uh, Proxima Centauri, uh, a signal that's 4.2 light years away. So, you know, the- the thought is, uh, it'd be- it'd be kinda cool if there's life out there, alien life, uh, but it'd be really cool if we could fly out there and check, and so what kind of propulsion, and d- do you think about what kind of propulsion will allow us to travel close to the speed of light or, you know, half the speed of light, all those kinds of things that would allow us to get to Proxima Centauri in a reasonable, in a lifetime?

    30. NBNatalya Bailey59:50

        You know, there's the project Breakthrough Starshot-
17. 1:03:07 – 1:10:05

    How to build a rocket company

    1. NBNatalya Bailey1:03:07

       someday.

    2. LFLex Fridman1:03:08

       You, uh, you're the co-founder of, just like we've been talking about, Axion Systems. Uh-

    3. NBNatalya Bailey1:03:12

       Yeah.

    4. LFLex Fridman1:03:12

       ... this is... Would you say a space propulsion company?

    5. NBNatalya Bailey1:03:15

       Yes.

    6. LFLex Fridman1:03:16

       Broadly speaking. Um, so, uh, how do you... Big question, how do you, uh, build a rocket company? From like (laughs) a propulsion company from one person, from two people to 10 people plus? And actually, you know, take it to a successful product?

    7. NBNatalya Bailey1:03:41

       Yeah. Well, I think the early stage is quite, uh... I'm not supposed to use the word "easy" when you work in rocket science, but straightforward. Um, when you're working on something, you know, sexy like an ion engine, it's more straightforward to raise money and, and get people to come work for you because the vision's really exciting and... Actually, that's something I would say is very important throughout is, um, a really exciting vision because when everything, you know, goes to crap, um, you need that to get people-

    8. LFLex Fridman1:04:15

       Yeah.

    9. NBNatalya Bailey1:04:15

       ... getting themselves out of bed in the morning and thinking of the, the higher purpose there. Um, and, you know, another thing along the way that I think is key in, in building any company is, um, the right early employees that also have their own networks and can bring in, um, a lot of people that, um, you know, really make the, this, the whole greater than, than just the sum of the early team.

    10. LFLex Fridman1:04:46

        And how do you build that? Like how do you find people? It's like asking, uh, like (laughs) how do you make friends? But is there, um... Is it, uh, is it luck? Is there a system? Like how... I- in terms of the people you've connected with, the, the people, um, you built the company with. W- is there some thread, some commonality, some pattern that you find to be, to hold for what makes a great team?

    11. NBNatalya Bailey1:05:17

        Uh, I think, you know, personally, uh, a thread for me has been my network and being able to draw on that a lot, but also giving back to it as much as possible in like an unsolicited sort of way. Like making connections between people that, you know, maybe didn't ask but that, uh, I think could be really fruitful and, um, even, you know, weirder than that is just really getting... You know, having weird, uncomfortable conversations with people, like at a conference, and getting over the small talk quickly and getting to know them quickly and having a relationship that stands out and then being able to call on them later because of that. Um, and I think that's... It's... That's been because I'm introverted and I, you know, wanna poke my eyes out instead of go and do small talk and so-

    12. LFLex Fridman1:06:14

        Yeah.

    13. NBNatalya Bailey1:06:14

        ... I huddle in a corner with one person and, you know, we talk about aliens or things like that.

    14. LFLex Fridman1:06:19

        Yeah.

    15. NBNatalya Bailey1:06:19

        And, um, so, you know, that's all to say that, you know, having a strong network, I think is really important but a genuine one. And let's see, other ways to build a rocket company. Kind of making sure you're paying attention to the sweeping trends of the industry. So everybody just cares about cost and, um, being able to get out ahead of that and even more than we ever thought we'd need to as far as what we needed to price our systems at. You know, people for... Since the start of the, the US space industry, they've been paying 20, 25 million in adjusted dollars for an ion engine and seeing that now people are going to want to pay 10K for an ion engine, um, and just staying-

    16. LFLex Fridman1:07:07

        Wow.

    17. NBNatalya Bailey1:07:08

        ... out ahead of that and those kinds of things. Um, so, you know, being out in the industry and, and talking to as many people-

    18. LFLex Fridman1:07:14

        It's crazy.

    19. NBNatalya Bailey1:07:14

        ... as possible.

    20. LFLex Fridman1:07:15

        So there's a drive... I mean, I suppose-

    21. NBNatalya Bailey1:07:17

        Yeah.

    22. LFLex Fridman1:07:17

        ... SpaceX really pushed that.

    23. NBNatalya Bailey1:07:18

        It's frustrating for me. (laughs)

    24. LFLex Fridman1:07:19

        (laughs) Yeah. So, uh, SpaceX really pushed this-

    25. NBNatalya Bailey1:07:22

        Mm-hmm.

    26. LFLex Fridman1:07:23

        ... uh-

    27. NBNatalya Bailey1:07:24

        Yeah.

    28. LFLex Fridman1:07:24

        ... the application of, uh, I guess, capitalism of driving the price down of, um, basically forcing people to ask the question, "Can me- this du- can this be done cheaper?"Um, thi- this can lead to, like, big problems, I would say, in th- in the following sense. I see this in the car industry, for example, that, uh, p- people have s- it's such a small margin for profit. Like, they've driven the cost of everything down so much that there's literally no room for innovation-

    29. NBNatalya Bailey1:07:59

        Yes.

    30. LFLex Fridman1:08:00

        ... for taking risks. So like, cars ... (sighs) Which is funny because not until Tesla, really, which is one of th- in a long, long time, one of the f- first successful new car companies that's constantly innovating. Every other car company is really boring in terms of their technological innovation. They innovate on design and style-
18. 1:10:05 – 1:14:38

    SpaceX and commercial spaceflight

    1. NBNatalya Bailey1:10:05

    2. LFLex Fridman1:10:05

       (laughs) But in general, just on the topic of SpaceX, you know, 2020 has seen some difficult things for human civilization and, uh, it's been a lot of ... First of all, it's an election year. There's been a lot of drama and division about that. There's been riots over all different, um, reasons. Racial division. There's been, obviously, a virus that's testing the very fabric of our society. But there's been really i- for me, at least, super positive things, which, inspiring things, which is, uh, SpaceX and NASA, uh, doing the first commercial-

    3. NBNatalya Bailey1:10:42

       Yeah.

    4. LFLex Fridman1:10:43

       ... f- human f- flight. Uh, launching humans to space and did it twice successfully.

    5. NBNatalya Bailey1:10:49

       Mm-hmm.

    6. LFLex Fridman1:10:50

       Uh, what is that, um ... Did you get to watch that launch? Did you, uh ... What does it make you feel? Uh, do you think this is, uh, first days for a new era of, um, space exploration?

    7. NBNatalya Bailey1:11:05

       Yeah, I did watch it. We played it outside on a big screen at our place.

    8. LFLex Fridman1:11:09

       That's awesome.

    9. NBNatalya Bailey1:11:10

       And, um, I was a little ... You know, they kept saying, "Bob and Doug. Bob and Doug." (laughs) And, you know, astronauts usually are, um, treated with a little bit (laughs) more fanfare so it felt very casual, but maybe that was a good, a good thing. Like, this is the era of commercial, crewed-

    10. LFLex Fridman1:11:28

        Mm.

    11. NBNatalya Bailey1:11:29

        ... missions and-

    12. LFLex Fridman1:11:29

        Oh, it wa- it was a little bit more, um, what is it? Um, what's his name? Chris Hadfield, like, playing guitar.

    13. NBNatalya Bailey1:11:37

        Yeah.

    14. LFLex Fridman1:11:37

        It's more ... It's a different flavor to it of a-

    15. NBNatalya Bailey1:11:41

        Yeah, exactly.

    16. LFLex Fridman1:11:42

        ... more like fun, playful, celebrity type of-

    17. NBNatalya Bailey1:11:46

        Yes, exactly.

    18. LFLex Fridman1:11:47

        ... astronaut versus, um, the, the au- the aura of the magical sort of, h- heroic-

    19. NBNatalya Bailey1:11:53

        Right. Yeah.

    20. LFLex Fridman1:11:53

        ... element of the single human representing us in space.

    21. NBNatalya Bailey1:11:56

        Yes.

    22. LFLex Fridman1:11:57

        Yeah.

    23. NBNatalya Bailey1:11:58

        I think that's all for the better though. It's so cool that it's such a commonplace thing now that we send ... You know, I can't believe that sometimes I'll have to ... You know, you don't even realize that astronauts are coming and going all the time, you know, splashing back down and it's just so common now, but, uh, that's quite magical I think. Um, so yes. We did watch that. I love, love, love that we finally have that capability again to send (laughs) people to the space station. Um, and it's just really exciting to see the private sector stepping up to fill in where the government has pulled back in the US and I think pulled back way too soon as far as exploration and science goes. Probably pulled back at the right time for commercial things, um, and, and getting that started, but, um, I'm really happy that it's even possible to do that with private money and, and companies.

    24. LFLex Fridman1:12:55

        Do you like the, the kind of the model of competition of, uh, NASA funding ... I guess that's how it works is like they're providing quite a bit of money from the government and then, then private companies compete to be, uh, to be the delivery vehicles for-

    25. NBNatalya Bailey1:13:11

        Yes.

    26. LFLex Fridman1:13:11

        ... the, whichever the, th- the, uh, the, the government missions, like NASA missions.

    27. NBNatalya Bailey1:13:17

        Yes. I think for ... This type of mission is a little bit kind of straddles, um, commercial and, and science, so I think it's good, but I do, in general, feel like, um, we've pulled back too much on, you know, NASA's role in the science and exploration part and I think our pace is too slow there, you know, for my liking, (laughs) I suppose.

    28. LFLex Fridman1:13:43

        What do you mean on the scienti- uh, okay. So did you have ...I mean, on the cost thing, do you feel like NASA was a little too bureaucratic in a sense, like, too slow, too heavy cost-wise in their effort, like when they were running things purely without any commercial involvement?

    29. NBNatalya Bailey1:14:03

        So I suppose it's more that I just want the government to fund.

    30. LFLex Fridman1:14:08

        I see, yeah.
19. 1:14:38 – 1:21:13

    Advice to startup founders

    1. NBNatalya Bailey1:14:38

    2. LFLex Fridman1:14:38

       So you have quite a bit of experience, first of all, st- starting a company yourself, but also I saw, maybe you can correct me, but you s- you have a quite- quite a bit of knowledge of, um, just in- in general the startup experience of building companies that you've interacted with people. W- if, is there- is there advice that you can give to somebody, to a founder or co-founder who wants to launch and grow a new company and do something big and impactful in this world?

    3. NBNatalya Bailey1:15:10

       Yes. Uh, I would say, you know, like I mentioned earlier, but make sure the vision is something that, you know, will get you out of bed in the morning and- and will get... and that you can rally other people around you to- to achieve, uh... 'Cause I see a lot of folks that sort of cared about something or saw a window of opportunity to do something and, you know, startups are hard and- and more often than not just being opportunistic isn't going to be enough to make it through all the really crappy, um, things that are going (laughs) to happen.

    4. LFLex Fridman1:15:48

       So the vision just helps you psychologically to carry through the hardships for you and the team in this situation.

    5. NBNatalya Bailey1:15:53

       Yeah, you and the team. Yeah, exactly.

    6. LFLex Fridman1:15:56

       Okay.

    7. NBNatalya Bailey1:15:56

       To kind of younger people interested in getting into entrepreneurship, I would say, you know, stay as close to, like, first principles and- and fundamentals as you can for as long as you can, um, because really understanding the problems, you know, if it's something scientific or hardware-related or, um, even if it's not, but having a deep understanding of- of the problem and the customers and what people care about and, um, how to move something forward is more important than taking all of the entrepreneurship classes in undergrad.

    8. LFLex Fridman1:16:31

       So being able to think deeply, yeah.

    9. NBNatalya Bailey1:16:33

       Yeah, exactly.

    10. LFLex Fridman1:16:34

        (laughs) Yeah. Well, have you been surprised about how much, like, pivoting is involved? Like, basically rethinking what you thought initially would be the right direction to go?

    11. NBNatalya Bailey1:16:44

        Yeah.

    12. LFLex Fridman1:16:44

        Or is there, if you think deeply enough, that, uh, you can s- stick in the same direction for long enough?

    13. NBNatalya Bailey1:16:50

        So our, you know, our guiding star hasn't changed at all. Um, so that's been pretty consistent, but we, w- within that, we flip-flop on so many things, um, all the time. And, you know, to give you one example, it's do you stop and build a first product that's well-suited to maybe a smaller, less exciting segment of the market, or do you stay head down and focus on, you know, the big swing and- and trying to hit it out of the park right away? And we've flip-flopped between that, and there's not a blanket answer and there are a lot of factors, but, um, that's a hard one. And I think one- one other piece for the aspiring founder, um, spending a lot of time and effort on the culture and people piece is so important and is always an afterthought and something that I haven't really seen, like, the founders or- or executives at companies purposefully carve out time and- and acknowledge that, yes, this is going to take a lot of my time and resources and then... But you see them after the fact trying to repair the, you know, bro culture or whatever else is broken at the company. Um, and I think that it's starting to change. Um, but just to be aware of it from the beginning is important.

    14. LFLex Fridman1:18:19

        Right. I- I guess it should be part of the vision of what kind of place you want to create or what kind of, like, human beings...

    15. NBNatalya Bailey1:18:28

        Yeah, exactly. Like, you can't wait five, 10 years and then just slap an HR person onto trying to fix it. Like, it has to be thoughtful from the beginning.

    16. LFLex Fridman1:18:37

        Yeah. Umm, don't get me started on the HR people.

    17. NBNatalya Bailey1:18:41

        (laughs)

    18. LFLex Fridman1:18:42

        Uh, (sighs) don't leave HR to HR people, but I'll just leave it at that. You didn't say that, I said it. Okay.

    19. NBNatalya Bailey1:18:48

        (laughs)

    20. LFLex Fridman1:18:49

        (laughs) Uh, yeah, HR is... Actual HR is really important. It's just so, so important.

    21. NBNatalya Bailey1:18:55

        Yes, but so overlooked.

    22. LFLex Fridman1:18:55

        Yeah, culture is so important. Yeah. So...

    23. NBNatalya Bailey1:18:58

        And then I also was surprised, like I thought you could say, "Here will be our culture and our values," and that it was kind of distinct from who I and my co-founder were as people.

    24. LFLex Fridman1:19:11

        Yeah.

    25. NBNatalya Bailey1:19:11

        And it was like, no, that's not how that works.

    26. LFLex Fridman1:19:12

        Yeah.

    27. NBNatalya Bailey1:19:13

        We just kind of, like, ooze our our behaviors and then the company grows around that. So you have to do a lot of, like, introspection and-

    28. LFLex Fridman1:19:21

        Yeah.

    29. NBNatalya Bailey1:19:21

        ... self-work to not-

    30. LFLex Fridman1:19:23

        Yeah.
20. 1:21:13 – 1:29:31

    Book recommendations

    1. LFLex Fridman1:21:13

       Uh, okay.

    2. NBNatalya Bailey1:21:14

       Yeah.

    3. LFLex Fridman1:21:14

       So, people love it when, uh, we talk about books. Is there books, maybe three or so, technical fiction, philosophical, that had an impact on your life and you might recommend? And for each, is there an idea or so that you, uh, take away from it?

    4. NBNatalya Bailey1:21:31

       Yes. Um, so I've been a voracious reader all my life, um, and I'm always reading, like, three or four or five books at a time. Um, uh, and now I use Audible a lot too, and, you know, podcasts and things like that. Um, so I think the first one that stands out to me is, um, Ten... It's a novel, um, Tender is the Night by Fitzgerald, and I, I read it when I was much younger, but I went back and read it recently, and it's not that good, so I'm not sure why it has, like, such an (laughs) important place, um, in my literary history. But, um, I love Fitzgerald as an author because he's very, he has very, like, flowery prose, um, that I can just picture what he's saying, but he does it in a, such a creative way. I remember that one in particular 'cause it, you know, I read a ton as a kid too, but it kind of set me, it was like the beginning of my adult reading life, and, um, getting into classics and, um, I kind of, I do feel like I, they seem intimidating maybe, and then I realize that they're all just, like, love stories. Um, uh, so-

    5. LFLex Fridman1:22:51

       (laughs) Yeah, uh, isn't everything (laughs) a love story-

    6. NBNatalya Bailey1:22:53

       You know?

    7. LFLex Fridman1:22:53

       ... somehow?

    8. NBNatalya Bailey1:22:53

       Yeah, it's really- (laughs)

    9. LFLex Fridman1:22:55

       Yeah, at the bottom.

    10. NBNatalya Bailey1:22:55

        Even, you know... I don't know. I, I was surprised that even, like, a lot of the Russian authors, um, you know? That's all, they're all-

    11. LFLex Fridman1:23:03

        Yeah.

    12. NBNatalya Bailey1:23:03

        ... just love stories. Um-

    13. LFLex Fridman1:23:04

        We humans are pretty simple. There's not much-

    14. NBNatalya Bailey1:23:06

        Yeah.

    15. LFLex Fridman1:23:06

        ... to work, there's not much to work with, so.

    16. NBNatalya Bailey1:23:08

        So, I think maybe that was it. It made, like, that whole world less intimidating to me, and, and cemented my love-

    17. LFLex Fridman1:23:15

        That's cool. (laughs)

    18. NBNatalya Bailey1:23:16

        ... for reading.

    19. LFLex Fridman1:23:17

        People should just approach the classics like, "Th- there's probably a love story in here."

    20. NBNatalya Bailey1:23:20

        Chick flicks. Yeah. (laughs)

    21. LFLex Fridman1:23:21

        Sure. (laughs) "It's a, it somehow boils down to a chick flick-"

    22. NBNatalya Bailey1:23:24

        Yes.

    23. LFLex Fridman1:23:24

        "... so I'll just relax and, and enjoy the ride." Uh-

    24. NBNatalya Bailey1:23:27

        And then-

    25. LFLex Fridman1:23:28

        So, what else?

    26. NBNatalya Bailey1:23:29

        Um, changing gears quite a bit, um, The Beginning of Infinity. Do you know it? By David Deutsch. Um, so he's a physicist, um, I think at Cambridge or Oxford, and so I was introduced, like, more formally to a lot of the ideas, like a lot of th- the things we've talked about he, um, has a lot more, like, formalism and, um, physics rigor around. And so I got introduced to, you know, mo- more, like, jargon of how to think about some of these ideas, um, um, you know, like memes and, you know, DNA as, as ultimate meme, um, uh, the concept of infinity and, um, objective beauty. Um, but he has a really strong grounding in, in physics. Um, and then-

    27. LFLex Fridman1:24:19

        So he has a rigorous way of talking about these, like, big topics?

    28. NBNatalya Bailey1:24:22

        Yeah. So that was very mind-opening to me to read that, but it also, I think is probably part of why I ended up marrying my husband is related to that book, and then I've had some other really great connections with people because I had read it and so had they. Um, so-

    29. LFLex Fridman1:24:40

        I like how you turned that, that bo- even that book into a love story.

    30. NBNatalya Bailey1:24:44

        (gasps) I did. I know.

Episode duration: 1:34:40