Kind: captions
Language: en
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
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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
projec