gentlemen. I'm Jean LeGall. I'm

President of the French Space Agency and

the President elect of the International

Astronautical Federation, and it is my

pleasure to welcome you here at the 67th

International Astronautical Congress.

Elon Musk is founder, C.E.O., and lead

designer of SpaceX. Elon founded SpaceX

in 2002 with the goal of revolutionizing

space technology and ultimately enabling

humans to become a multiplanetary

species, and that's the plan he's going

to lay out for us today.

SpaceX has had a number of firsts

including as the first private company

to deliver cargo to and from the

International Space Station and the

first entity to land a nautical thrust

booster back on land and on ships out at

sea.

Please join me in welcoming Elon Musk.

[APPLAUSE].

ELON MUSK: Thank you. Thank you very

much for having me. I look forward to

talking about the SpaceX Mars

architecture. And what I really want to

achieve here is to make Mars seem

possible, make it seem as though it's

something that we can do in our

lifetimes and that you can go. And is

there really a way that anyone can go if

they wanted to?

I think that's really the important

thing.

So, I mean, first of all, why go

anywhere?

Right?

I think there are really two fundamental

paths. History is going to bifurcate

along two directions. One path is we

stay on Earth forever and then there

will be some eventual extinction event.

I don't have an immediate doomsday

prophecy, but eventually history

suggests there will be some doomsday

event. The alternative is to become a

space-faring civilization and a

multiplanet species, which I hope you

agree that is the right way to go.

Yes?

[APPLAUSE].

That's what we want.

[APPLAUSE].

Yeah. So how do we figure out how to

take you to Mars and create a

self-sustaining city, a city that is not

really an outpost but can become a

planet in its own right and thus we can

become a truly multiplanet species?

You know, sometimes people wonder, Well,

what about other places in the solar

system?

Why Mars?

Well, just to sort of put things into

perspective, this is -- this is what --

this is an actual scale of what the

solar system looks like. So we're

currently in the third little rock from

the left. That's Earth. Yeah, exactly.

And our goal is to go to the fourth rock

on the left. That's Mars. But you can

get a sense for the real scale of the

solar system, how big the sun is and

Jupiter, Neptune, Saturn, Uranus. And

then the little guys on the right are

Pluto and friends.

This sort of helps to see, it's not

quite to scale, but it gives you a

better sense for where things are. So

our options for going to -- for becoming

a multiplanet species within our solar

system are limited. We have, in terms of

nearby options, we've got Venus. But

Venus is a high-pressure -- super

high-pressure hot acid bath. So that

would be a tricky one. Venus is not at

all like the goddess. This is not in no

way similar to the actual goddess.

So it is really difficult to make things

work on Venus.

Mercury is also way too close to the

sun. We could go potentially on to one

of the moons of Jupiter or Saturn, but

those are quite far out, much further

from the sun, a lot harder to get to.

Really, it leaves us with one option if

we want to become a multiplanet

civilization, and that's Mars. We could

conceivably go to our moon, and I have

nothing against going to the moon, but I

think it's challenging to become

multiplanetary on the moon because it's

much smaller than a planet. It doesn't

have any atmosphere. It's not as

resource rich as Mars. It has a 28-day

day, whereas the Mars day is 24 1/2

hours. And in general, Mars is far

better suited to ultimately scale up to

a self-sustaining civilization.

Just to give some comparison between the

two planets, there are actually --

they're remarkably close in a lot of

ways. In fact, we now believe that early

Mars was a lot like Earth. And, in fact,

if we could warm Mars up, we would, once

again, have a thick -- a thick

atmosphere and liquid oceans.

So, where things are right now, Mars is

about half again as far from the sun as

Earth. So it has decent sunlight. It's a

little cold, but we can warm it up. It

has a very helpful atmosphere which, in

the case of Mars being primarily CO2

with some nitrogen and argon and a few

other trace elements, means that we can

grow plants on Mars just by compressing

the atmosphere. And it has nitrogen,

too, which is also very important for

growing plants.

It will be quite fun to be on Mars,

because you will have gravity which is

about 37% that of Earth, so you will be

able to lift heavy things and bound

around and have a lot of fun. And the

day is remarkably close to that of

Earth.

So we just need to change that bottom

row, because currently we have 7 billion

people on Earth and zero on Mars.

So there's been a lot of great work by

NASA and other organizations in early

exploration of Mars and understanding

what Mars is like, where could we land,

what's the composition of the

atmosphere, where is there water, or

ice, we should say. And we need to go

from these early exploration missions to

actually building a city.

The issue that we have today is that if

you look at a Venn diagram, there's no

intersection of sets of people who want

to go and can afford to go. In fact,

right now you cannot go to Mars for

infinite money. Using traditional

methods, you know, if taking sort of a

holistic style approach, an optimistic

cost number would be about $10 billion

per person. For example, the Apollo

program, the cost estimates are

somewhere between $100 billion to $200

billion in current-year dollars, and we

sent 12 people to the surface of the

moon, which was an incredible thing and

I think probably one of the greatest

achievements of humanity.

But that's -- that's a steep price to

pay for a ticket. That's why these

circles only just barely touch. So you

can't create a self-sustaining

civilization if the ticket price is $10

billion a person. What we need is a

closer -- is to move those circles

together. And if we can get the cost of

moving to Mars to be roughly equivalent

to a median house price in the U.S.,

which is around $200,000, then I think

the probability of establishing a

self-sustaining civilization is very

high. I think it would almost certainly

occur -- not everyone would want to go.

In fact, I think a relatively small

number of people from Earth would want

to go. But enough would want to go and

who could afford the trip that it would

happen. And people could get

sponsorship. And I think it gets to the

point where almost anyone, if they saved

up and this was their goal, they could

ultimately save up enough money to buy a

ticket and move to Mars. And Mars would

have labor shortage for a long time so

jobs would not be in short supply.

But it is a bit tricky because we have

to figure out how to improve the cost of

trips to Mars by 5 million percent. So

this is -- this is not easy. I mean,

it's -- and it sounds like virtually

impossible but I think there are ways to

do it. This translates to an improvement

of approximately 4 1/2 orders of

magnitude.

These are the key elements that are

needed in order to achieve the 4 1/2

order of magnitude improvement. Most of

the improvement would come from full

reusability, somewhere between 2 and 2

1/2 orders of magnitude. And then the

other two orders of magnitude would come

from refilling in orbit, propellant

production on Mars and choosing the

right propellant. So I'm going to go

into detail on all of those.

Full reusability is really the super

hard one. It's very difficult to achieve

reusability for even an orbital system,

and that challenge becomes even

substantially greater for a system that

has to go to another planet. But as an

example of the difference between

reusability and expendability in

aircraft -- and you can actually use any

form of transport. You could say a car,

bicycle, horse. If they were single-use,

almost no one would use them. It would

be too expensive. But with frequent

flights, you can take something like an

aircraft that costs $90 million and if

it was single use, you would have to pay

half a million dollars per flight. But

you can actually buy a ticket on

Southwest right now from L.A. to Vegas

for $43, including taxes. So that's -- I

mean, that's a massive improvement.

Right there it's showing a four order of

magnitude improvement.

Now this is harder -- the reusability

doesn't apply quite as much to Mars

because the number of times they can

reuse the spaceship is -- the spaceship

part of the system is less often because

the Earth-Mars rendezvous only occurs

every -- every 26 months.

So you get to use the spaceship part

roughly every two years.

Now, you get to use the booster and the

tanker as frequently as you'd like. And

so it makes -- that's why it makes a lot

of sense to load the spaceship into

orbit with essentially tanks dry and

have it have really quite big tanks that

you then use the booster and tanker to

refill while it's in orbit and maximize

the payload of the spaceships that when

it goes to Mars, you really have a very

large payload capability.

So as I said, refilling in orbit is one

of the essential elements of this.

Without refilling in orbit, you would

have a half order of magnitude impact

roughly on the cost. By "half order of

magnitude," I think the audience mostly

knows, but what that means is each order

of magnitude is a factor of ten. So not

refilling in orbit would mean a 500%,

roughly, increase in the cost per

ticket.

It also allows us to build a smaller