Natalya Bailey: Rocket Engines and Electric Spacecraft Propulsion | Lex Fridman Podcast #157
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 monk pack low carb snacks four sigmatic mushroom coffee blinkist an app that summarizes books and sun basket meal delivery service so the choice is snacks caffeine knowledge or 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 and 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 wander 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 an apple podcast follow on spotify support on patreon or connect with me on twitter at lex friedman and now here's my conversation with natalia bailey 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 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 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 allegedly i mean in in our dimensions and yeah 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 it's the it's this carl sagan idea that they may be communicating at a time scale that's totally different like their signals are on a totally different time scale or like a totally different kind of medium communication it could be it could be our own it could be the birth of like human beings like that the whatever the magic that makes us who we are the collective intelligence thing that could be aliens themselves that could be the medium communication like the nature of our consciousness and intelligence itself is the medium of communication and like being able to ask the questions themselves i've never thought of it that way like actually yeah asking the question whether aliens exist might be the very medium by which they communicate it's like they they send questions so some this like collective emergent behavior is is the signal is the signal yeah so interesting yeah because maybe that's how we would communicate with if you think about 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 an impact multiverse of course uh that would have a signal an effect on the most possible the most 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 what 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 right my train of thought has never gone gone there but i like it 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 oh you're hopeful are you excited by the possibility that there's intelligent life out there sort of you work on on the engineering side of things it's this very kind of focused pursuit of uh moving things through space efficiently but you know if you zoom out one of the cool things that this enables us to do is find or get even intelligent life just life on mars on europa or something like that does that excite you does that scare you oh it's very exciting i mean it's the whole reason i went into the field i'm in is to contribute to building the body of knowledge that we have as a species um so very exciting do you think there's life on mars i like uh no longer well already living but at currently living but also no longer living like that we might be able to find life as some people suspect basic microbial life 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 uh so i'm not sure about this close to home that would be really exciting yes like do you think about the drake equation much of what that was what yeah what got me into all of this yeah yeah because 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 that would be super exciting because that means there's like trillions of planets yeah basic life out there though of all the planets in our solar system earth is clearly the most habitable so i would not be discouraged if we didn't find it on another planet in our solar system true and again that life could look very different it's habitable for earth-like life right but it could be totally different i still think that trees are quite possibly more intelligent than humans but their intelligence is carried out over time scale that we're just not able to appreciate like they might be running the entirety of human civilization and we're just like too dumb to realize that they're they're the smart ones maybe that's the alien message it's in the trees the trees uh yeah it's not in the uh monolith in the utah deserts and the trees right yeah so let's go to space exploration how do you think it would get humans to mars 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 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 so really you know i say that because there's nothing truly scientifically or technologically impossible about doing that soon it's more you know politically and financially and and those are the obstacles i think to them well i wonder of when you colonize with you know more than i say five people on mars you have to start thinking about the kind of uh like rules you have on mars and speaking of the cold war who gets to own the land you know you start planting flags you start to make decisions and uh like spacex says this night 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 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 it sounds very much like uh 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 we humans need a little bit of a competition do you think that's necessary to succeed in um to get the necessary investment or can the pure pursuit of science be enough no i think we're seeing right now the pure pursuit of science i mean that results in pretty tiny budgets for exploration there has to be some disaster impending doom 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 you know i don't wish that there is some catastrophe coming our way that that spurs us to do that yes i'm not sure what the business model is for colonizing mars yeah exactly 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 you should have a path to making money in like the next 10 years well and 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 um like bacteria is what we're supposed to be doing in the first place so maybe we can go but should we and and i'm probably a an 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 we're 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 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 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 yeah i don't have a lot of color to the dreams i have about way in the future and 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 this again i'm probably unusual 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 in a truly you know artificial intelligence way or ai as as we kind of use it today 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 but if not you know maybe not even that petri dish so i see i think what i'm saying is you know i see a much bigger role in the future of ai for space exploration 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 and then human civilization destroys itself and then they'll just be this floating spacecraft that eventually get somewhere or not that's a sad thought like this lonely spacecraft just kind of traveling through space and humans are all dead well it depends on what the what the goal is right another way to look at it is we've preserved it's like a little time capsule of knowledge dna you know that we've that will outlive us that's beautiful yeah that's how i sleep at night so you also mentioned that you wanted to be an astronaut yes so even though you said you're unusual and thinking like it's nice here on earth and then 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 it becomes sort of more open to civilian travel and that kind of thing like are you uh like vacation wise like if you talk if we're talking vacations would you like to vocation on earth or vacation on mars 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 and do some experiments there uh that's being decommissioned which is sad but you know there will be others i'm sure um the iss is being decommissioned 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 so it's primarily like a research lab essentially yes research lab in space that's a cool way to say it's like the coolest possible research lobby that's where i wanted to go and now though my you know risk profile has changed a little bit i've three little ones and um i won't i won't be in the first thousand people to go to mars let's put it that way yeah earth is kind of nice we have our troubles but overall it's pretty nice again it's the netflix okay let's talk rockets uh how does a rocket engine work or any kind of engine that can get us the space or float around in space the basic principle is conservation of momentum so um you throw stuff out the back of the engine and and that pushes the rocket and the spacecraft in the other direction so there are two main types of of rocket propulsion the one people are more familiar with is chemical because it's loud and there's fire and that's what's used for launch and is more televised so um in in those types of systems you usually have a fuel on an oxidizer and 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 directed out the back and and then that momentum exchange pushes the spacecraft forward is there an interesting difference between liquid and solid fuel in those contexts 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 and the other main category is electric propulsion so instead of chemical energy you're using electrical energy usually from you know batteries or solar panels and uh in this case the stuff you're pushing out the back 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 same idea stuff out the back and everything else goes forward cool so those are the big two categories what what's the difference maybe in like the challenges of each the use cases of each and how they're used today the physics of each 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 yeah fire fire yeah 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 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 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 kind of what people care about there is is making it more fuel efficient so the chemical stuff you can get a lot of 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 the engine cycles and things like that and then on electric propulsion i find it like much more refreshingly poorly understood uh lots more mysteries yeah i think so one of the classes i took in college spent we spent 90 percent 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 it's like that's that's interesting yeah and 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 material science and fluid dynamics and electrostatics and and it's just very intriguing to me um first of all can you actually zoom out even more like because you mentioned ion propulsion engine is a subset of electrolytes so like maybe is there a categories of electric engines and then we can zoom in on ion propulsion 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 and then there are also some other types of plasma engines but that don't fit into those two categories so just kind of other plasma like a vasomere 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 of engine that i work on which is has a lot of similarities to an ion engine but could be considered its own class called a colloid thruster colloid cool okay so what is an ion propulsion i imagine okay so in an ion engine you have an ionization chamber and you inject the propellant into that chamber and this is usually a neutral gas like xenon or argon so you inject that into the chamber and you also inject a stream of really hot high-energy electrons and everything's just moving around very randomly in there and the the whole goal is to have 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 plasma yes okay and now you have um 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 electric field that we set up between two grids with holes in them and you know in terms of area the same amount of those ions also makes runs into the walls and lose their charge and that's where some of the inefficiencies come in but the very lucky few make it to those holes and in that grid and they're two grids actually and you apply a voltage differential between them and and that sets up an electric field and a charged particle in an electric field creates a force and so those ions are accelerated out the back of the engine and the reaction force is is what pushes the spacecraft forward 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 those ions will come back and hit the spacecraft because it's a positive beam so you also have to have an external cathode 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 what temperature we're 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 um i mean is that an interesting thing to talk about in a sense that is that a interesting distinction or is the heat i mean it's all going to be hot no so it's important especially for some of these smaller satellites people are into launching these days so the it's important because you have the plasma but also those high energy electrons are hot and if you have a lot of those that are going into the walls you do have to care about the temperature so um i am having trouble remembering off the top of my head i think they're at like 100 electron volts in terms of the electron energy and then i'd have to remember how to convert that into kelvin can you stick your hand in it is that no no temperature not recommended yeah okay so what's a colloid engine 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 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 use as a source of ions and if you have ions and you put them in a field you generate a force so they recognize that but part of being able to leverage that technique is being able to kind of manipulate those liquids on a scale of nanometers or or you know very few microns so you know the diameter of a human hair or something like that 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 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 that 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 this way 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 so you have this balance and the liquid assumes a cone when it's perfectly balanced like that and at the tip of a cone the radius of curvature goes to zero right at the tip um and uh the radius sorry the electric field um right at the tip of a sharp object would go to infinity uh because it goes is 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 a jet of ions instead starts you know issuing from the tip of of that liquid so the field becomes strong enough there that you can pull ions um out of the liquid what is the liquid we're talking about so there's a bunch of different ones 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 what we use are called ionic liquids and they're really just positive they're they're very similar to salts but they happen to be liquid over a really wide range of temperatures this sounds like really cool okay so how big is the uh how big is the kona we talk what what's the size of this cone that generates that 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 oh i was imagining something slightly bigger but so like this is so this is tiny tiny yes hence the only being able to do it recently yeah that's right so this is all controlled by a computer i guess like or like how do you control how do you create a cone that generates ions on a scale of nanometers exactly 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 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 cool um but it also reduces the actual field we have to the voltage we have to apply to create that field because the field will be much stronger if we can already give the liquid a tip to form on and those tips we form have radii of curvature on the order of probably like single microns so we are working at a little bit larger scale but once we create that support and the electric field can be focused at that tip then the tiny little cone can form so wait so there's something in them there's an already like a hard material that like gives you the base for the cone and you're pouring like liquid over it whatever from the bottom yeah it's porous so we actually supply it from the back of the chip and then liquid forms on top yeah on that structure yeah and then you somehow make it like super sharp the liquid so the ions can leave and then we've applied that field to get those ions and that same field then accelerates them that's awesome and there's like a bunch of these yeah i should have i should have brought something um so well you could just pretend that you have some nanometer cones on so actually you know kind of about this scale um we build we call them thruster chips and it's just a convenient form factor and it's a square centimeter and on each square centimeter today we have about 500 of the actual physical we call them emitters those physical cones um and we're working on increasing that by a factor of four in the coming months in size or in in number and the density the number of emitters within the same square centimeter chip so that thing because i think i've seen pictures of you with like a tiny thing yeah and that must be the thing okay so that's an engine um so that is kind of the ionization chamber and thrust producing part of it what's not shown you know in that picture um is the propellant tank so we can keep supplying more and more of the liquid to those emission sites and then we also provide a power electronic system that talks to the spacecraft and turns our device on and off so that's the colloid engine that's the core of the coolidge um it's the way i've been talking about it it's um more of ion electrospray colloid um tends to mean like liquid droplets coming off of the jet but if you make smaller and smaller cones you get pure ions so we're kind of like a subset of colloid yes what uh aspects of this you said that it's been full of mystery from the physics perspective what aspects of this are understood and what are still full of mystery yeah recently um we've been understanding the kind of instabilities and and stable regimes of um you know how much liquid do you supply and and what field do you apply and um why is it flickering on and off or why does it have these weird behaviors so that's in the past just couple years that's become much more understood um i think the two areas that come to mind as far as um not as well understood are um the boundary between you know you have um we we actually use kind of big molecular ions and if you're looking at the molecular scale you have you know some ions that you've extracted and they're in this electric field one ion you know it's a big molecule it's getting energy from the electric field and some of that energy is going into the bonds and making it vibrate and doing weird things to it sometimes it breaks them apart and then zooming out to the whole beam the beam has some behaviors as this beam of ions and there's a big gap between what are those what how do you connect those and how do we understand that better so that we can understand the beam performance of of the engine is that a theory question as an engineering question theory definitely we're axion is a startup and we're more in the business of building and testing and observing um and characterizing and we're not really diving much into that theory right now okay zooming out a little bit on the physics uh apologize for the way too big of a question but to you from either us you mentioned axion is you know more sort of an engineering endeavor right performer 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 in this space and then i'm going to 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 which i find kind of exciting and it makes me want to dig in more there and i was just you know 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 at a scale of like nano yeah i mean you're it's if you look further it's quantum too but it it all is you capillary action at the quantum level yeah so i would i i it all comes back to me to you know material science there's so much we don't understand at these sizes um and i i find that inspiring and exciting 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 and it's you know just a partial differential equation but that kind of connectedness of the universe you know i don't want to use options pricing and the universe and the same but you know what i mean this connectedness i find really magical yeah the patterns that mathematics reveals seems to echo in a bunch of different places yes yeah there's just weirdness it's like it really makes you think i think you're definitely living in a simulation like whoever programmed like that that's your conclusion is using is using like shortcuts to program it like they didn't they just copy and pasted some code for the different parts yeah think of something new or just paste from over there they won't notice my conclusion from that was i'm gonna go interview for finance jobs so i had like a little detour that's the back that's the backup option so in terms of using uh kohler engines what's what's an interesting difference between a propulsion of a rocket from earth when you're standing in the ground to orbit and then the kind of propulsion necessary for once you get out or better to like deep space to to move around 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 very interesting for exploration and and even for missions with humans on them um 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 you know solar panels are really inefficient and bulky and batteries i don't know when anybody's ever going to improve battery technology i know a lot of people that work on that and nuclear power you we could have a lot more powerful electric propulsion systems so they would be extremely fuel efficient but more instantaneous for us to do more interesting missions um if we could start launching more nuclear systems but so like so something that's powered nuclear-powered that's the right way to say it yeah but is it a small enough container that could be launched yeah so um i mean as a world we do launch 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 i i heard i think elon described or somebody i think i think it was elon described the uh ev tall like electrical vertical takeoff and landing vehicles so basically saying rockets i'm 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 electrical uh what do you see a world with the rockets that we use to get into orbit are also electric based uh it's possible you can produce the thrust levels you need but you need this uh a much bigger power supply and 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 i think a lot of people would still have an issue with that but someday 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 value and uh and yet we are seem to be i mean based on the history based on the excellent hbo series russian with the chernobyl it seems like we have our risk estimation about this particular power drastically inaccurate but that's that's a fascinating idea that we would use nuclear as a source for our vehicles uh and not just in outer space that's cool i'm going to look into that that's super interesting well um just last year trump eased up a little bit on the regulations and nasa and hopefully others are they're starting to pick up on the development so now is a good time to look into it because there's actually some movement is that a hope for you to to explore different energy sources that the entirety of the vehicle uses something like uh like the entirety of the propulsion systems for all aspects of the vehicle's life travel is the same or electric is it possible for it to be the same like the cool load engine being used for everything you could 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 engine 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 okay so it's possible all right but uh yeah it turns down to the power source the power source it's that's really interesting but for the current power sources and its current use cases what's the use case for electric like the the the corallite engine can you talk about where they're used today 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 health thrusters and orange and um there's 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 and then you know most people want to do things a little bit more interesting like maneuver to avoid being hit by space debris or perhaps lower their orbit to take a higher resolution image of something and then return at the end of your mission you're supposed to responsibly get rid of your satellite whether that's burning it up but if you're in geo you want to push it higher into graveyard orbit um what's geo what's um so low earth orbit and then geosynchronous orbit or geostationary orbit and there's a graveyard yeah so those satellites are at um like 40 000 kilometers so if they were to try to push their satellites 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 deorbit 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 cool so 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 the the life of a satellite is just like oh crap trying trying to avoid like literally 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 that's not yeah but it's not zero um and it yeah it takes a lot of um planning and people on the ground and you know none of that really i don't think right now is autonomous oh that's not good yeah and then we have a lot of folks taking advantage of you know moore's lawn cheaper spacecraft so they're launching them up without the ability to maneuver themselves and they're like well i don't know just don't hit me 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 affordable in that instead of launching one satellite they'll launch you know 20 small ones yeah so if one gets taken out 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 are the things that go and hit the other satellites yeah so do you see a world where like in your sense in your own work and just in the space industry in general do you see that people are moving towards bigger satellites or smaller satellites is there going to be a mix like what's and what do we talk what what does it mean for satellite to be big most and small what's that 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 cost a couple billion dollars and now you know our first launches were on um satellites the size of shoe boxes that were built by high school students so that's a very different you know to give you the two ends of the spectrum big satellites will 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 there you also can't just go to small satellites 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 morris law that's that's different so it's always going to be the size it it will be you know unless there's some new physics that comes out that i'm not aware of but if you need a resolution and you're at an altitude that kind of sets your size of your telescope but because of moore's law we we are able to do a lot more with smaller packages and and with that you know comes more affordability and opening up access to space to more and more people well what's the smallest satellite you've seen go up there like what what are the smallest kind you said shoe boxes yeah so i think you know the smallest their uh smallest common form factor can fit a softball inside wow so that's 10 centimeters on each side um but then there are some companies working on you know fractions of that even and they're doing things like iot type application so it's very low you know bandwidth type things but they're finding some niches for those you mean like there's a business there's a thing to do with them yes what do you do with a small satellite like that um you can you know track a ship going across the ocean is 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 and you have to have propulsion on that you have to have a little engine no those are just you know letting fall out of the sky um okay yeah but what uh so what kind of solid lights would you equip a colloid engine on anything that's bigger than probably about 20 kilograms 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 that's a lot of use cases what's this what's the small set like what what's category it's actually very big i think it's like 700 kilograms or keep hitting my microphone um maybe a thousand kilograms down to 200 kilograms or people have their own kind of definitions of how they break them up but small sat is still quite large and then um it's kind of also applied as a blanket term for anything that's not a school bus size satellite so we need to get our jargon straight industry so what do you see do you see a possible future where you know there's a few thousand satellites up there now a couple of thousands of them functioning do you see a future where there's like millions of satellites up up in orbit or if we get millions tens of thousands which just seems like where the natural trajectory of the way things are going now is going tens of thousands yes uh the two you know buckets of applications one is imaging and the other is communication so imaging uh i think that will plateau because one satellite or one constellation can take an image or a video and sell it to you know infinity customers but if you're providing communications like broadband internet or satellite cell or something like that satellite phone um you know you're you're limited by your transponders and and so on so to serve more people you actually need more satellites and and perhaps at the rate you know our data consumption and things are going these days um yeah i can see tens of thousands of satellites can i ask you a ridiculous question yes so i've recently watched this documentary on netflix about flat earthers that bel you know the people that believe in a flat earth as somebody as somebody who develops propulsion systems for for satellites and for a spacecraft what's uh to use the most convincing evidence that the earth is around probably some of the photos taken from the moon photos on the moon okay so it's not from from the satellite space yeah i think seeing though that perspective i maybe i'm just i'm answering to personally because i really love those photos they're beautiful yeah 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 you know planetary body and you're like oh okay can you actually see her i i don't i don't know yeah i'll send you i'll send you that picture because i love the pictures or videos of just earth from more from orbit and so on right yeah those that's really beautiful that's like a perspective shifter that's the pale blue dot right it probably appears tiny yeah and just that you know juxtaposition of the insignificance but you're not going to build this really cool thing i just love that yeah that'd be cool i can't i personally love the idea of humans stepping out of mars i'm such a sucker for the romantic notion of that and being able to take pictures from mars like so you would go i have i uh yeah i would be what did you say you said you wouldn't be not in the first thousand 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 that was like two million people so i would like to show up when they're signing those documents okay so maybe the two million oh that's an interesting way to think about it because like then we're like participating as citizenry and defining the direction so it's not the technical risk you just don't want to show up somewhere that's like america before yeah because it's i from a psychological perspective it's just going to be a stressful mess as people have studied right it's like it's people most likely the process of colonization like looks like basically a prison like you're in a very tight enclosed space with people and it's just a really stressful environment you know how do you select the kind of people that will go and then there'll be drama there's always drama 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 yeah i'm more worried about the psychological difficulties and also just not being able to tweet like what are you gonna how are you yeah there's no netflix so yeah maybe not in the first million but the first hundred 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 are still doing to this day start over from scratch there's uh just our financial system it could be like based on cryptocurrency you could think about like how democrat you know we have we have now the technology that can enable pure democracy for example if we choose to do that yeah as opposed to representative democracy all those kinds 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 electric base 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 like even ion engines is there like breakthroughs that might 10x the thing like really improve it so you know the real game changer would be propellant-less propulsion and so every couple years you see a new now a startup or a researcher comes up with some contraption for producing thrust that didn't require you know we've been talking about conservation of momentum mass times velocity out the back um forward yes 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 casmir 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 propellant-less forces but um that that could be real and could be something that that we use eventually what would be the power source yeah the most recent engine like this that has was just debunked this year i think in in march or something was called the m drive and um supposedly 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 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 their momentum was conserved 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 of the chamber or something like that so um forward it again um but you know it would be so wonderful for everybody if we could figure out how to do it but i don't know 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 enabling like yeah so hook that up to the nuclear power supply there you go okay yeah but still in terms of speed in terms of trying to so there's recently us already i think been debunked or close to being debunked but the uh signal a weird signal from our nearby friends nearby exoplanets from proxima centauri a signal that's 4.2 light years away so you know the the thought is uh it'd be it'd be kind of cool if there's life out there alien life uh but it'd be really cool if you could fly out there and check and so what kind of propulsion and did 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 and have reasonable in a lifetime you know there's the project breakthrough star shot yeah um that's looking at sending those tiny little chip sets um accelerating really fast yeah using a laser so launching them and then while they're still relatively close to the earth you know blasting them with some i forget what even what power level you needed to to accelerate them fast enough to get there in 20 years crazy sounding but uh a lot of people say that's a legitimate like it's crazy sounding but it can actually pull it off yeah i love that project because there are a lot of different aspects you know there's the laser there's how do you then um get enough power when you're there to send a signal back no part of that project is possible right now but i think it's really exciting but do you uh do you see like human uh like a spacecraft with a human on it so it's like a heavy one being like us inventing new propulsion systems entirely like do you ever see that in the on the radar of propulsion systems like that or are they completely out there in the impossible well we're going to quickly leave the realm of what i can describe with any credibility but i think i think because of special relativity if we try to accelerate some mass to close to the speed of light it becomes infinitely heavy and then we just don't we'd have to like harness a lot of suns to do that or you know it's just that that math doesn't quite work out but you know in in my child's my childlike heart i believe that you know we're missing something um whether it's you know dark matter or other dimensions and if you can just have some anti-matter and a black hole and then ride that around and somehow you know turn that into some mess with gravity somehow yeah i i feel like we're missing lots of things in this puzzle and that you know i wonder how is that puzzle yeah right well i can speak with confidence as a descendant of uh apes that we don't know what the hell we're doing yeah so there's uh we're like really confident like physicists are really confident that we've like got most of the picture down right it feels like oh boy it feels like that we might not even be getting started on some of the essential things that um that would allow us to engineer systems that would allows to travel to space much much faster yeah and there's even things that are much more commonplace that we can't explain but we've started to take for granted like um quantum tunneling you know um just things like oh the electron was here with this energy and now it's here with this energy and it's just tunneling um but so i you know we're missing a lot of the picture so yeah i don't know to you know use your same question from earlier i don't know if you and i will see it but um yeah someday you uh you're the co-founder of just like we've been talking about axion systems uh yeah this is would you say space propulsion company yes broadly speaking um so how do you big question how do you uh build a rocket company from like a propulsion company from one person from two people to ten people plus and actually you know take it to a successful product 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 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 a really exciting vision because when everything you know goes to crap um you need that to get people 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 the right early employees that also have their own networks and can bring in a lot of people that you know really make the this the whole greater than than just the sum of the early team yeah how do you build that like how do you find people it's like asking like how do you make friends but is there um is it uh is it luck is there a system like how in terms of the people you've connected with the the people um you built the company with is there some thread some commonality some pattern that you find to be to hold for what makes a great team 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 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 want to poke my eyes out instead of go and do small talk and so i huddle in a corner with one person and you know we talk about aliens or things like that 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 out ahead of that and those kinds of things um so you know being out in the industry and talking to as many people as possible so there's a drive i mean yeah spacex really pushed that frustrating for me yeah so uh spacex really pushed this uh yeah the application of uh i guess capitalism of driving the price down of um basically forcing people to ask the question can be this can this be done cheaper this can lead to like big problems i would say in the following sense i see this in the car industry for example that uh people have 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 taking risks so like cars which is funny because not until tesla really which is one of the in a long long time one of the first successful new car companies that's constantly innovating every other car company is really pouring in terms of their technological innovation they innovate on design and style and so on that you that people fall in love with the look and so on but it's not really innovation the in terms of the technology in it it's really boringly the same thing and they're really afraid to have taken risks and that's a big problem for rocket space too is like you if you're cutting out costs you can't afford to innovate to try out new things and then yeah that's definitely true with i ion engine then right so but what um so how do you compete in this uh in this space do you by the way see spacex as a competitor uh and what do you say in general about the competition in the space is it really difficult as a as a business to compete here no i i don't see spacex as a competitor um and i see them as one day not too long from now a customer hopefully um i mean to compete against that i think you just have to do things in an unconventional way so bringing silicon mems manufacturing to propulsion you know nasa doesn't make ion engines using a batch mass producible technique they have you know one guy that's been making their ion engines for 20 years like bespoke pieces of jewelry so um bringing things to what you're trying to innovate to to make them you know in our case more cost effective was was really key well i like the idea of uh somebody putting out ion engines on like etsy yeah my advisor at mit would you know the thruster chip i was holding up he would wear one as a lapel pin 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 of all different um reasons racial division there's been obviously a virus that's testing the very fabric of our society but this has been really i for me at least super positive things which inspiring things which is uh spacex and nasa uh doing the first commercial yeah human flight uh launching humans to space and did it twice successfully 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 yeah i did watch it we played it outside on a big screen at our place and um i was a little you know they kept saying bob and doug bob and doug and you know astronauts usually are um treated with a little bit more fanfare so it felt very casual but maybe that was a good a good thing like this is the era of commercial crude missions and it was a little bit more um what is it um what's his name chris hadfield like playing guitar yeah it's more it's a different flavor to it of uh yeah exactly more like fun playful celebrity type yes exactly astronaut versus uh the or the aura of the magical sort of heroic elements of the single human representing us in space yes yeah 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 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 people to the space station and it's just really exciting to see the private sector stepping up to fill in where the government has pulled back in the u.s 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 and getting that started but i'm really happy that it's even possible to do that with private money and and companies 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 whichever the the the government missions like nasa missions 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 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 i suppose what do you mean ana science 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 so i suppose it's more that i just want the government to fund i see yeah and and maybe nasa's not the best organization to to do it rapidly but i think that you know again depending on the goals we're just kind of at the very starting point of space exploration and science and and understanding so we should be spending more money there and and not less and um other countries are starting to spend more and more and i think we'll file we'll fall behind because of that so you have quite a bit of experience first of all to start starting a company yourself but also i saw maybe you can correct me but you you have quite quite a bit of knowledge of um just in general the startup experience of building companies you've interacted with people if is there is there advice that you can give to somebody to a founder co-founder who wants to launch and grow a new company and do something big and impactful in this world 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 because 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 to happen so the vision just helps you psychologically to carry through the hardships for you and the team yeah you and the team yeah exactly 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 because really understanding the problems you know if it's something scientific or hardware related or even if it's not but having a deep understanding of of the problem and the customers and what people care about and how to move something forward is more important than taking all of the entrepreneurship classes in undergrad so being able to think deeply yeah yeah exactly yeah 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 or is there if you think deeply enough that you can stick in the same direction for long enough so our you know our guiding star hasn't changed at all um so that's been pretty consistent but we 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 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 that's a hard one and i think one one other piece for the aspiring founder spending a lot of time and effort on the culture and people peace is so important and is always an afterthought and something that i haven't really seen like the founders or or executives that 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 and i think that it's starting to change um but just to be aware of it from the beginning is important right 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 yeah exactly like you can't wait five ten years and then just slap an hr person on to trying to fix it like it has to be thoughtful from the beginning yeah and don't get me started on hr people uh don't leave hr to hr people but i'll just leave it at that you didn't say that i said it okay uh yeah hr's actual hr is really important this is so myself yes but so culture so important yeah 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 and i was like no that's not how that works we just kind of like ooze out our behaviors and then the company grows around that so you have to do a lot of like introspection and self work to not end up with a shitty culture it's kind of a it's a it's a relationship but as opposed to a relationship with two people it's relationship with many people yeah and you yeah you communicate so much indirectly by who you are you have to be yes you have to live it yeah uh as somebody i think about this a lot because generally i'm full of love and all those kinds of things but like i also get like really passionate and when i see somebody in in the context of work especially when i see somebody who i know can do a much better job and they don't do a great job i can lose my in a way that's like steve jobsian and you have to think about exactly the right way to lose your if you're going to or if at all you have to really think through that because it sends a big signal uh you know sometimes that's okay like if you do deliberately like if you're going to do it deliberately if you're going to say like i'm going to be the kind of person that allows this and pays the cost of it but you can't just think it's not going to have a cost yes this was like the first thing i worked on with my leadership coach was to how not to just snap people when they were being an idiot and um first i got really good at apologizing that was the first step because it was going to take longer to fix brilliant behavior and then she i've got i'm actually a lot better at it now and it started with things she's like every time you walk through a doorway think you know calm and take breaths before responding and there were all sorts of these little things we did and it was mostly just changing the habit yeah yeah oh boy it's a long road okay so people love it when 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 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 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 10 it's a novel um tender is the knight 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 important place um in my literary history but um i love fitzgerald as an author because he's very he's 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 because 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 yeah isn't everything yeah it's really at the bottom 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 just love stories are pretty simple there's not much to worry there's not much to work with so so i think maybe that was it it made like that whole world less intimidating to me and and cemented my love that's for reading people should have just approached the classics like there's probably a lot of chick flicks yeah so it somehow boils down to a chick flight so just relax and enjoy the ride and then so what else um changing gears quite a bit um the beginning of infinity do you know what 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 the things we've talked about he um has a lot more like formalism and physics rigor around and so i got introduced to you know more like jargon of how to think about some of these ideas um you know like memes and you know dna as as ultimate meme um the concept of infinity and um objective beauty um but he has a really strong grounding in in physics um and then there's a rigorous way of talking about these like big 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 i like how you turn that that even that book into a love story i did i know it's good it's good your robot has a heart exactly and okay the third uh series is it's just it's harry potter um of course which somehow connects to i haven't read harry potter i'm really sorry forgive me forgive me uh but uh i've read tolkien but just harry potter just haven't haven't gone to it but your company name is somehow i think connect with harry potter right i think they heard this my i always feel like i have to justify my fandom um the first three books came out when i was 10 so i went along this journey with harry um age-wise and i read them all like nine or ten times all seven books and i think um anything that just keeps you reading as is what's important and you know there i have lulls where i don't feel like reading anything so i'll reread a harry potter or a you know trashy detective novel or something and and i don't really care and that's why i mention harry potter because it you know whatever just keeps me reading i think is important and um it was a big part of my life growing up and then yes axion i the official of the naming of the company is that axion is like a concatenation of accelerate and ion but it actually came from accio the summoning charm and then we just added an n and it was perfect what's the summoning charm that's just one of the spells yeah it um probably most notably harry uses it to summon his broomstick out of his dorm room when he's battling a dragon somewhere else so he says the spell and the broomstick comes to him so summoning in that way okay there we go this is brilliant so the the big thing is that it's something that you've carry with it's like your car is your safe place you return to something like the harry potter that you know i reread them still um whatever keeps me reading i think is is the most important thing okay i got it so yeah i'm actually the same way in terms of the habit of it it's important yeah it's important to just keep yeah keep reading but i have found myself struggling a little bit to because i listen to a lot of audiobooks now i've struggled to then switch back to reading seriously uh because just read so many papers read so many other things it feels like if i'm going to sit down and have the time to actually focus on the reading i should be reading like blog posts or papers or more condensed kind of things yeah but there there's a huge value to just reading long form still yeah and you know my husband was never that into fiction but then someone told him or he heard um you know you learn a lot of empathy through reading fiction um so you could think of it that way well yeah that's kind of what yeah yeah the and it's also fiction is a nice unlike not less so with nonfiction is a chance to travel i see it as kind of traveling yeah as you go to this other world and it's it's nice because it's like much more efficient you have to get on a plane you don't have to and you get to meet all kinds of new people it's like people say they love traveling and i say i love traveling too i just yeah read fiction i told my um three-year-old that that was why we read so much because we you know see the places in our mind and i'm like it's basically like we're watching a movie you know that's how it feels and she's like i prefer watching frozen with popcorn with her response but yeah there's some power to the imagination right that's it's not just like watching a movie because some something about of our imagination because it's it's the words in the world that's painted somehow mixing in with our own understanding of our own hopes and dreams our fears it like mixes up in there and the way we can build up that world from just the page yeah you're you're really creating the world just with the like prompts from the book right yeah yeah that's different than watching a movie yeah which is why it hurts sometimes to watch the version and then you're like that's not at all yeah yeah i imagined it well we kind of brought this up in terms of uh the depending on what the goals are let me ask the big uh your your friends of manila's he's obsessed with this question so let me ask the big ridiculous question about the meaning of life uh do you have uh you ever think about this one do you ever uh ponder the the reason we're here he's descends the vapes on this spinning ball in the middle of nowhere yeah i don't i don't think one ends up in the field of space propulsion without thinking of these existential questions uh yeah all the time or bill's a business yeah i know um yeah we've touched on a lot of the different pieces of this i think so i i have a bunch of thoughts um i do think that you know the goal isn't the meaning [Music] isn't anymore just to be like a petri dish of bacteria that reproduces and um you know where survival and reproduction are the main objectives and maybe it's because now we're able to answer these ask those questions um that's maybe the turning point um and instead i i think it's really the the pursuit and generation of knowledge and and so if if we're taken out by an asteroid or something i think that it will have been a you know meaningful endeavor if somehow our knowledge about the universe is preserved somehow um and the next civilization isn't starting over again um so that that's that's i always yeah i resonated with that that i always loved the mission of google from the early days of making the world's sort of information and knowledge searchable i always loved that idea i was loved i was donated as people should to wikipedia i just love wikipedia i feel like it's the it that's one of the greatest accomplishments of just a humanity of us together especially wikipedia and this opens like in this open community way putting together different knowledge just like on everything we've talked about today i'm sure there's a wikipedia page about ion engines and i'm sure it's pretty good yeah like it's i don't know that's that's incredible and obviously that can be preserved pretty efficiently at least wikipedia and you just you'll be like human civilization is all like burning up in flames as there's this one usb drive slowly traveling yeah wikipedia that's on from the beginning of our chat that one lonely spacecraft it just means wikipedia and then it will have been a civilization well spent um so pushing that knowledge along yeah through like one little discovery at a time is is one of is a core aspect to the meaning of it of it all yes and i also i i haven't yet figured out what the connection you know an explanation i'm happy with yet for how it's connected but um evolving beyond just the the survival piece too i think like we touched on the the emotional aspect something in there about cooperation and you know love and so i in my day-to-day that just boils down to you know the pursuit of knowledge or improving the human condition and being kind love and knowledge yeah exactly so i'm pretty at peace with that as the meaning right now makes sense while you work on yeah spacecraft propulsion yes exactly like literal rocket science natalia this is amazing conversation you work on such an exciting engineering field and i think this is like what 20th uh 21st century will be remembered for as space exploration so this is super exciting uh space that you're working on so and thank you so much for spending your time with me today thanks for having me this was fun thanks for listening to this conversation with natalia bailey and thank you to our sponsors monk pack low carb snacks four sigmatic mushroom coffee blinkist an app that summarizes books and sun basket meal delivery service so the choice is snacks caffeine knowledge or delicious meal choose wisely my friends and if you wish click the sponsor links below to get a discount and to support this podcast and now let me leave you with some words from carl sagan all civilizations become either space-faring or extinct thank you for listening and hope to see you next time