All language subtitles for Discovering.The.Cosmos.S01E04_English

♪

NARRATOR: Planet Earth.

It's been home to humanity
for over 200,000 years.

But with a population of
7.5 billion and counting

and with limited resources,

this planet might
not support us forever.

Some scientists
are beginning to think

that to safeguard
humanity's future

we need to do something radical.

That is the theory

of one of the world's
most prominent physicists.

DR. HAWKING: I
am Stephen Hawking.

I am convinced that
humans need to leave Earth

and make a new
home on another planet.

To stay risks annihilation.

It could be an
asteroid hitting the Earth.

It could be a new
virus, climate change,

nuclear war, artificial
intelligence gone rogue.

We can, and must, use our
curiosity and intelligence

to look to the stars.

We must do it now,
before humanity is overtaken

by some disaster that we can
neither anticipate nor control.

NARRATOR: In this
program we investigate

the latest science,
technology and engineering

to find out, if
Professor Hawking is right, and

we do have to leave the Earth
and colonize another planet,

is it possible?

Is there another planet out
there that we could call home?

DR. VIGAN: On average we find
a few new planets each day.

NARRATOR: How will we get there?

DR. LUBIN: There is
no fundamental reason

why we couldn't build systems

which would be
capable of propelling humans

to intergalactic distances.

NARRATOR: And how will we
set up a new human civilization

on an alien world?

DR. RUIZ: If you're
going to be on another planet

you're going to have to
deal with its atmosphere.

You're going to have to
deal with growing plants.

NARRATOR: Humanity may be facing
its greatest challenge ever.

♪

NARRATOR: Professor Steven
Hawking and other scientists

believe that to secure the
future of the human species,

we must colonize another planet.

If they are right, our
first task must be to decide,

where are we going?

Is there another world out there
that could be our new home?

The planets of
our own solar system

would be relatively
nearby for us to reach.

But the extreme
conditions on these planets

mean they are not
ideal for human habitation.

However, beyond our
solar system, our galaxy,

the Milky Way, has
over 300 billion stars,

and we now believe that many
of them, just like our own sun,

have planets around them.

These are known as exoplanets,

and, with
potentially billions out there,

perhaps one of them could be a
good target for a human colony.

One of the world's best
places to search for exoplanets

is here in Chile

at Paranal Observatory's
Very Large Telescope or VLT.

Danielle George is an engineer

and an expert in
radio astronomy technology.

She's come to see

some of the world's most
powerful telescopes in action.

♪

During nighttime observations,

the VLT is operated
from this control room.

Arthur Vigan and
Raphael Galicher

are visiting
astronomers from France.

They are already hard
at work observing a star

to see if it has an exoplanet.

DR. VIGAN: So now you can
see there is the star here.

DR. GEORGE: Oh, great.

DR. VIGAN: What
we will want to do

is to subtract
all of this light,

which is all this
light from the star

that we are not
really interested in.

What we are interested in

is the light of a faint
planet that would be around.

DR. GEORGE: So you've got
about an hour to integrate it,

now have you?
DR. VIGAN: Yeah.

♪

NARRATOR: This
"direct imaging" method

collects visible
light from the star,

and from any planet
that might be orbiting it.

The result is like
taking a photograph.

DR. VIGAN: Ah, no, I'm not sure.

DR. GALICHER: Not convinced.

DR. GEORGE: So
you think this is it?

DR. GALICHER: I
think this is it.

DR. VIGAN: Yeah,
it's possible it was...

DR. GEORGE: So, team here,
optimist, pessimist is it?

[all laughing]

DR. GEORGE: I
hope it's a planet.

DR. VIGAN: We would
have to re-observe that star

in a few months from now,

and if it's still
moving with the star

then it means it's a planet.

DR. GEORGE: So if it
turns out to be an exoplanet,

do you guys get to name it?

DR. GALICHER: Yeah. With a
B after the name of the star.

DR. GEORGE: Excellent. And
do we know what star it is?

DR. VIGAN: Yeah, we know,
but we cannot tell you. It's...

DR. GEORGE: Oh, okay.
DR. GALICHER: Yeah.

DR. VIGAN: I mean, until it's
confirmed and it's published,

everything's a secret.

DR. GEORGE: So is
there a general consensus

amongst planet hunters

to how many potential
exoplanets there could be?

DR. VIGAN: Well, we are
really starting to think that

planets are
ubiquitous in the universe.

And they are really everywhere.

I mean, we've
discovered the first exoplanets

about 25 years ago, and now
we are finding more and more.

Almost on average we find
a few new planets each day.

DR. GEORGE: Each day... wow.

NARRATOR: In the last 25 years,
astronomers around the world

have discovered
over 3,000 exoplanets.

So could one of
these be a candidate

for a new Earth colony?

It turns out
it's not that simple.

Most would be
nightmare destinations.

♪

WASP 12b is an
enormous hot gas giant

five times the size of Jupiter.

It's so close to its star
that surface temperatures

are over 3.5
thousand degrees Fahrenheit,

and its star's huge gravity

pulls the planet
into a football shape.

Visiting this planet
would be spectacular.

Its clouds could be
made of corundum --

an aluminum oxide that is the
basis of rubies and sapphires.

[choir sings Mozart's "Requiem"]

Kepler 1520b is a rocky planet
2,000 light years away from us

and about the size of Mercury.

The heat from its
star is so intense

that it vaporizes the rock
from the planet's surface,

giving it a
comet-like tail as it orbits.

HD 189733b is another gas giant.

Particles of glass silicate
form rain in its atmosphere,

giving this planet a
bright blue color...

and scorching winds
of nearly 2,000 degrees

encircle the planet.

♪

For humans to survive,

we need to find a
planet that's rocky...

and about the same size
and density as the Earth

so that its gravity
will be similar to our own.

Then, the crucial thing
we need to sustain life

is liquid water at the surface.

That means we
need to find a planet

that orbits in the
habitable zone of its star...

the distance
where the temperature

is just perfect
for liquid water.

For our sun, a
yellow dwarf star,

the habitable zone stretches
from around the orbit of Venus

to the orbit of Mars.

Earth sits neatly
right in the middle.

But these
Earth-like rocky planets

are impossible to detect using
direct imaging techniques.

The planets are just too small
and their stars too bright.

Christophe Galfard
is a science writer

who studied theoretical
physics with Stephen Hawking.

Today he is meeting
astronomer James Jenkins

to find out more about an
alternative method he uses

to look for these planets
that are hidden from view.

DR. GALFARD: So tell
me, what does the swingball

got to do with finding planets?

DR. JENKINS: Well,
if we consider that

the ball is a planet

and the post there represents
our star in the center,

we can see that the
planet orbits the star.

And not only that, the planet
exerts a gravitational force,

it pulls the star.

And we can see with
this analogy of the post

that there's a wobble,
a movement of the star,

and that's what we search
for when we look for planets.

DR. GALFARD: All right!

NARRATOR: James and his
team used this technique

to study the star
Proxima Centauri.

At 4.2 light years away,
it's the closest star to us,

after our own sun.

Inside the astronomers'
living quarters at Paranal,

James reveals what they
found as the results came in.

DR. JENKINS: Each night
as this data was coming in

and we were putting
those points on this plot,

we started to see
this kind of oscillation,

and this wobble of the star
that we can see here told us,

hey, the indications we
found before were correct.

DR. GALFARD: That then there is
probably something out there.

DR. JENKINS: There
is probably a planet.

Each night we were
seeing this confirmation.

And after three weeks,

we knew pretty much for
certain, Proxima b exists.

DR. GALFARD: So do
you think that planet

is pretty much the
best candidate we have

if we want to
colonize another world?

DR. JENKINS: I would have to
say the answer would be yes,

at this moment in time.

The fact that it's the
nearest star to our sun

and it has this planet
that could be Earth-like,

if in the future
we can build craft

that can travel
between the stars,

I think that Proxima b

would be basically the
first stop on that journey.

DR. GALFARD: That's
the best thing I've heard

for a long while.

DR. JENKINS: I'm
glad to hear that.

DR. GALFARD:
That's very good news.

♪

NARRATOR: Thanks to James and
his team's remarkable discovery,

we now know that
there is a planet

around our stellar
next-door neighbor

that could be
suitable for colonization.

Welcome to Proxima b.

The radial velocity method

doesn't just reveal
a planet's existence.

These observations also tell us

that Proxima b is a little
more massive than the Earth...

and it's almost
certainly a rocky planet.

Its year, the time it
takes to orbit its star,

is just 11.2 days.

That means this planet
must be very close to its star.

But because its
star is a red dwarf,

much smaller and
cooler than our sun,

this planet does sit
in the habitable zone.

And there might just be
liquid water at the surface.

Proxima b might be
our best destination

for mankind's new home.

But although it's
our nearest planet,

Proxima b is still
a very long way away.

Getting there, even with the
fastest rockets we have today,

would take thousands of years.

Professor Hawking
believes this will be

one of our biggest hurdles.

DR. HAWKING: This is
an enormous challenge.

We have lost the
momentum of the space race

that was driven by the Cold War.

We need to start again.

To leave Earth will
take a global approach.

Everyone should join in.

Our best minds need to
focus and rekindle the romance

and the exploratory
spirit of space travel

found in the early
lunar expeditions.

NARRATOR:
Engineers around the world

are now taking on
this challenge...

and new breakthroughs
in propulsion technology

might change the way
we travel to planets...

and to the stars.

♪

NARRATOR: We've now
found a target planet

that could be suitable for human
colonization... Proxima b.

But its distance from
the Earth, 4.2 light years,

is a staggering 25
trillion miles... far beyond

anything we've reached
with a spacecraft before.

Even the Saturn V, the
fastest rocket in history,

only has a top speed
of 24,000 miles an hour.

At that speed it
would take us 120,000 years

to reach Proxima b.

To succeed on our mission

we're going to need a
huge technological leap.

Incredibly, a man
in Houston, Texas,

thinks he is very
close to making this leap.

Franklin Chang Diaz

is a rocket scientist
and former astronaut.

DR. GALFARD: Is that you?

DR. DIAZ: That's me,
our first spacewalk.

We were doing
some construction job

on the
International Space Station.

NARRATOR: Franklin has
built a revolutionary rocket

in his workshop that's powered

not by traditional rocket
propellant, but by plasma.

Plasma is a stream of highly
energized charged gas particles.

Lightning is one example.

Because plasma has
so much more energy

than the gas produced
by a chemical rocket,

it could push a
spacecraft much faster.

DR. DIAZ: Here it is!
DR. GALFARD: There we go.

DR. GALFARD: Wow, nice.

DR. DIAZ: So this
is the vacuum chamber,

and the rocket is inside.

DR. GALFARD: So you're creating
the vacuum of space in there.

DR. DIAZ:
Absolutely, that's the point.

NARRATOR: Harnessing
plasma into an engine

could change the way we
travel in space forever.

DR. GALFARD: So how does
the engine actually work?

DR. DIAZ: The way
you make the plasma is

you start out with gas,
and it goes into a cavity.

In that cavity
there is an antenna,

and that antenna shines
radio waves into the cavity.

And the gas becomes a plasma.

It's about maybe
three, five million degrees.

DR. GALFARD: Now
you're talking hot.

DR. DIAZ: Now
you're talking hot.

And then you just let it go, and
that makes a heck of a rocket.

NARRATOR: The magnetic
field inside the chamber

directs the
energized charged plasma cloud

and forces it into a nozzle
shape to create a powerful jet.

DR. GALFARD: Can
we see it in action?

DR. DIAZ: We can
certainly see it in action.

DR. GALFARD: So that's
the back of the rocket.

DR. DIAZ: That's the business
end. Okay, here it comes.

NARRATOR: This superheated jet,

thousands of times hotter than
conventional rocket exhaust,

provides the engine's thrust.

DR. GALFARD: So with
this kind of thrust,

how fast can a rocket go?

DR. DIAZ: It can go
about 10 times faster

than a conventional rocket.

And that will get us to
Mars in as slow as 39 days.

DR. GALFARD: That's not bad.

DR. DIAZ: And that's
essentially the plan.

NARRATOR: Working with
NASA, Franklin is close

to trying out his
plasma rocket in space,

where he predicts
it could reach speeds

of over 100,000 miles per hour.

If it works, it could completely
transform space travel.

DR. DIAZ: We want to be able to
put out this rocket in service

in a matter of
three years from now.

We want to
completely do a paradigm shift

in the
transportation arena in space.

DR. GALFARD: So
Franklin, could your rocket

take us to
Proxima b, for instance?

DR. DIAZ: Wow, that's a long
way. This rocket as it is, no.

The way I think of it
it's more like a precursor

to the rocket that
could take you to Proxima b.

♪

NARRATOR: Though
Franklin is confident

that future generations
of his plasma rocket

will be able to
take us to an exoplanet,

for now his focus is on
travel within the solar system.

This rocket might
reach Mars in 39 days,

but it would still take 2,000
years to get to Proxima b.

If we want to leave
the Earth imminently,

we need technology
that's even faster.

♪

In California, a team led
by astrophysicist Philip Lubin

is working on an alternative
propulsion solution.

They think they can get
a spacecraft to Proxima b

in just 20 years,
powered only by light.

DR. LUBIN: We
can demonstrate that

light carries momentum
and energy very easily.

If you take the torch here and
shine it at these small vanes,

you can see that it will
begin to push the vanes around.

DR. GEORGE: That's just
the light that is doing that?

DR. LUBIN: Yeah, the
light itself transfers

momentum and energy to the
vane, and that propels it away.

DR. GEORGE: Okay, but that
isn't a very powerful light,

and I wasn't going very fast,

and that is also
very small as well.

DR. LUBIN: Yeah, it's
really a scaling problem.

Increase the power
level, then suddenly we have

a very effective tool
for propelling spacecraft

that are suitable
for interstellar flight.

NARRATOR: This might seem
like pure science fiction.

But we know it works.

Light from the sun has
been successfully propelling

the Japanese craft IKAROS

through space for
the last seven years.

Philip's masterplan is to
build a huge bank of lasers

that measures
over six miles across.

Their combined light
would push a spacecraft,

accelerating it to
one-fifth the speed of light

♪

His team is so confident
this technology will work,

they are already constructing a
fleet of small unmanned probes

that will use
this method to make

the 25 trillion-mile journey
to Proxima b in just 20 years.

Despite its small size, this is
a fully functional spacecraft,

armed with sensors, cameras

and even microscopic
rockets to help orient it.

NICHOLAS: Initially
what will happen is

that it will fly
sort of edge-on,

and once you get to Proxima
b, it will then flip up,

and its sensors will
take all of their data,

all of their
information, whether that be

a camera, temperature sensors,

and then it will actually flip
around and send that data back.

DR. GEORGE: So
effectively they could do

a fly-by type
thing of Proxima b?

NICHOLAS: Right.
And the idea would be

you would have
hundreds of these at a time.

You sort of make a mosaic of all
these individual data points

and you use that to paint
sort of a much bigger picture

of what you are looking at.

NARRATOR: Vessels like
these may be the first

to glimpse the
surface of Proxima b.

But currently, these
are just tiny probes,

only big enough for an
initial scouting trip.

Could we ever
really use this technology

to transport humans
to a distant planet?

DR. GEORGE: What I hadn't
quite appreciated before today

was how far along that
technology roadmap you were.

But can you scale that up,
can you use the same technology

to have humans
travel interstellar?

DR. LUBIN: There are many
hard problems in this project.

It's not a simple project, it's
not easy, and it's not cheap.

But there is no
fundamental reason

why we couldn't build
extremely large systems,

which would be
capable of propelling humans

to intergalactic distances.

It's going to be a
fundamental transformation

in human exploration.

DR. HAWKING: I have no doubt
that we will eventually find

ways of crossing the
immense distances of space

in just a few years.

One of our species' great
strengths is embracing new ideas

and evolving them into
cutting-edge technologies.

Just look at advances we've made

in the fields of medicine,
communications and electronics.

We only built the first
silicon chip only 60 years ago.

Now it powers just about
every aspect of our lives.

Our ingenuity will
get us to Proxima b.

NARRATOR: If these scientists
can fulfill their promise,

we may soon have a way to
transport humans to Proxima b

that takes just 20 years.

But how do we choose
these interstellar spacefarers?

And how many
should be in our crew?

As we've learned
from species on Earth,

if there are not enough
individuals to establish

a sustainable population, our
human colony could go extinct.

NARRATOR: We've now
found what might be

the perfect planet
for colonization...

and we're working on the
technology to get there.

Our next challenge is to decide

who we will send
on this epic voyage.

To investigate how
to choose our crew,

Danielle has come to the place

they've been selecting and
training astronauts for decades:

NASA's Johnson Space Center.

DR. BARRATT: It's
a bilingual station.

Everybody has to be proficient
in English and Russian.

NARRATOR: Astronaut
Mike Barratt has taken

two long-duration trips to
the International Space Station

and spent 211 days in space.

DR. BARRATT: All right,
let's take a look at the Orion.

NARRATOR: This is
the Orion Capsule,

NASA's newest spacecraft.

This is the vehicle
that will soon carry

the next
generation of astronauts

beyond low Earth orbit

for the first time
since the moon landings.

DR. BARRATT: We definitely look
for people who want to explore

and have the commitment
to leave your home planet

and go and make
another planet your own.

When you look at how people
have moved across our planet

from say Europe to
the Western world,

you first have the
explorers, and they're the ones

who see things
for the first time

and characterize what
the environment is like --

the risk, if you will.

And if it looks
like a good place to go,

you're followed by the pioneers,

the people who
learn to live there.

And typically pioneering
is also fairly austere,

but you go there
with a certain knowledge

and a certain resolve
that you're there to stay.

The pioneers are then followed
by the colonists, if you will.

The colonists bring what I would
call a snapshot of humanity,

of civilization
to occupy that spot,

and so we really acquire that
destination and make it our own.

We look at Mars now
as the next destination,

as something that's
remote and difficult to do.

But in the long run, Mars
will be an interway point --

it'll be an in- or outpost

from which we will
continue to branch out.

DR. GEORGE: So someone
sitting at home on the sofa now

could be an astronaut in
a few generations' time,

colonizing another planet?

DR. BARRATT:
Absolutely. We look forward to

a continual
expansion of civilization,

so the cycle will
repeat over and over

as we keep
pushing the boundaries.

We will start again with
the explorers and the pioneers,

and the colonists
will eventually follow.

[rocket engines firing]

NARRATOR: But how many of these
astronauts must reach Proxima b

in order to start
a permanent colony?

DR. HAWKING: There have always
been a few true explorers

who have never been stopped by
the adversity of the challenge.

However, it will take more than
explorers to colonize a planet.

We will need to
send enough people

to build a
complete new civilization.

NARRATOR:
Proxima b is so far away

that this mission
must be a one-way trip.

To form a permanent
settlement when they get there,

those original crew
members will need to breed.

They will be the founders
of a brand new population.

So how many people does it take

to form a
genetically sustainable colony?

♪

The answer might lie here

at Washington's
Smithsonian National Zoo.

Here they study
not human populations,

but endangered species.

These are golden lion tamarins.

Just 40 years ago they were
on the brink of extinction.

Population
geneticist Dr. Brandie Smith

was part of the team

behind the golden lion
tamarins' impressive comeback.

[cross talk]

DR. GEORGE: So why did they
nearly become extinct, Brandie?

DR. SMITH: Well, they
live in the same places

that humans like to live.

And so their habitat just began

to decrease and
become fragmented.

And the tamarins
just couldn't keep up.

So there were only
about 200 left in the wild.

I have another one, and they
were on the edge of extinction.

They were critically endangered.

And when
populations get that low,

you become
concerned because essentially

they start to lose
genetic variability.

And if climate change
came through, or a disease,

the populations
could be wiped out

because they don't
adapt to changing conditions.

NARRATOR: The
tamarins had a close shave.

Using a
controlled breeding program,

Brandie and her team
rescued this population,

and they are now off
the endangered list.

DR. SMITH: You want a
grape? It's a big grape...

NARRATOR: But that's a stark
reminder for our human colony.

If there's not enough genetic
variation among our crew,

they could easily go extinct.

So perhaps then we
should be handpicking

our best genetic specimens
to represent the human species.

DR. GEORGE: Could we choose
the individuals genetically

to make sure that we had all
of the right things we needed

once we got to the planet?

DR. SMITH: Well, the problem is,

you don't know
which genes to select.

So the ones that might confer
an advantage here on Earth

might be totally,
totally different

if we went to another planet.

They might not be the best, and
they could also be detrimental.

DR. GEORGE: So as a
population geneticist,

what's your professional opinion

on how we should
address this challenge?

DR. SMITH: You need
to collect a sample

that's large enough to
get a good representation.

You don't want to select.

You want it to be
a random population.

♪

NARRATOR: This
means that to succeed

in colonizing a
planet like Proxima b,

we must take potentially
thousands of astronauts.

And all of them will
need to spend decades

traveling through the
hostile environment of space.

Protecting their bodies

will be a huge challenge...

but a surprising new
discovery in the animal kingdom

might hold the solution.

NARRATOR: According
to Stephen Hawking,

a colony on Proxima b
may be humanity's destiny...

but a journey to
a planet like this

will challenge our
species like nothing before.

The human body is fragile,

and space is the most
hostile environment we know.

The experience of astronauts on
the International Space Station

reveals that spending time
in a weightless environment

is hazardous to the body.

Without gravity, humans
deteriorate very quickly.

Here at Johnson Space
Center, behind closed doors,

every astronaut is
studied for months

when they return to Earth.

Kate Rubins has
recently come back

from a 115-day
mission on the ISS.

Mike Barratt, as well as
being a fellow astronaut,

is also a leading
expert in space medicine.

DR. BARRATT: The human
body changes almost globally

when you put it
in weightlessness.

From the standpoint of fitness,
we do lose bone and muscle,

because we don't have

that normal daily
challenge of gravity.

But we also lose blood volume,

so that makes you really
good for weightlessness.

As it turns out, it is
very adaptive if you will,

but when you want come back to
Earth, it becomes maladaptive.

♪

NARRATOR: To
counteract this wasting,

all astronauts exercise for
two and a half hours every day

while on the ISS.

But it is not enough.

ARCHIVE: Standing
by for touchdown.

NARRATOR: By the time
they return to Earth,

astronauts are frail
and at risk of injury.

ARCHIVE: Flashing
that familiar smile,

Kate Rubins now out
of the Soyuz spacecraft.

MAN: Hey, welcome
back. You're looking good!

NARRATOR: Landing on
a planet in this state,

people would
struggle to build anything,

let alone a new civilization.

And the lack of gravity in space

also has a huge effect
on our sense of balance.

The day they return to Earth,

some astronauts have the
coordination of a toddler.

DR. GEORGE: One here?

NARRATOR: Five
months after her landing,

Kate is still recovering.

BRUCE: Whenever you
are ready and you go,

I'm going to hit
the start button.

WOMAN: Go.

BRUCE: So this actually
gives us a better reflection

of what a person is capable
of in a post-flight period.

Sprint. Sprint.

It's muscular power, it's
speed, agility, it's balance.

DR. GEORGE: Does
it feel weird then?

When you doing
it you're feeling,

man, this should be
really, really easy?

DR. RUBINS: Try doing it
on the deck of a moving ship.

That's about what it
feels like when we landed.

BRUCE: If you've landed
after six or seven months

of deep space cruise,
you don't necessarily

want to get out there
and do an agility test

or a maximum
strength test right away.

You may need a lander
large enough to accommodate

the entire crew
in for a few days

before you've gained a
little bit of strength

and sea legs, if
you will, land legs,

so that you could
walk to a habitat.

NARRATOR: Weightlessness
isn't the only danger

associated with
long-duration space travel.

Our crew would need to find ways

to make their
food and life support

last the 20-year
trip to Proxima b.

The confinement
would put them under

huge psychological stress,

and their bodies
would be exposed

to prolonged doses of radiation,

damaging their DNA and
leading to lethal cancers.

♪

Incredibly, though,
nature may offer a solution

to all of these problems --
and these bears hold the key.

DR. GALFARD: Hello, Rob.

NARRATOR: Dr. Robert
Henning is a pharmacologist

who has worked closely
with the European Space Agency.

DR. HENNING:
There's a bear in that den,

but it is too
dark here to see it.

But with a thermal camera

you can actually
pick up its body heat.

NARRATOR: Rob studies an
element of bear behavior

which no other
large mammal exhibits.

DR. HENNING:
Hibernation is not sleeping.

Hibernation is
slowing of metabolism.

DR. GALFARD: So it's
a bit like being alive,

but in extreme slow motion.

DR. HENNING:
Yeah, yeah. Absolutely.

NARRATOR: During hibernation,
animals need virtually no food.

If we could find a
way of putting our crew

into stasis like this on
their journey to Proxima b,

it would greatly
reduce the amount of supplies

they'd need to take.

But Rob thinks there would also
be another unexpected benefit.

DR. HENNING: Well,
the interesting thing

is that hibernators are
also protected from radiation.

DR. GALFARD: So you
are telling me that bears

hibernating in space would
not be harmed by radiation.

DR. HENNING: Yes.

DR. GALFARD: That's
crazy, you know that?

DR. HENNING: [laughing] Yeah.

♪

NARRATOR: Rob thinks
he's found the key chemical

that controls hibernation.

And it could be used to
put humans into stasis,

and protect their DNA
from radiation damage.

He discovered this in the cells
of another hibernating mammal

-- the hamster.

DR. HENNING: This
is a hamster cell

which has been in the
fridge for three days.

DR. GALFARD: Okay.

Agh, that's rotten eggs

DR. HENNING: That's
hydrogen sulphide, right.

DR. GALFARD: It smells bad.

DR. HENNING: It
smells bad, yeah.

DR. GALFARD: So that means that

the cells
themselves produced this?

DR. HENNING: They
produced the hydrogen sulphide.

Now we know hydrogen sulphide
can sort of replace oxygen.

It is not as
efficient as oxygen,

but it is probably efficient
enough to keep you alive,

and so we think this is an
important part of hibernation.

♪

NARRATOR: Rob uses a
chemical very similar

to hydrogen sulphide

to put human cells into
a state of hibernation.

And amazingly, when
he exposes these cells

to lethal levels of radiation,
their DNA remains undamaged.

DR. HENNING: So
this compound protects

against radiation damage.

The long jump would be

maybe we should feed the
astronaut this compound.

But if we put a
human into hibernation,

I don't have any idea
right now how to wake them up

and when to wake them up.

DR. GALFARD: So, knowing this,
would you try to hibernate,

to be put in hibernation?

DR. HENNING: I think so, yeah.

I've thought about
it a long long time,

and I just think that if I
were the first, I would do it.

NARRATOR: If we can use Rob's
hibernation method on humans

and find a way to
wake them up again,

they could arrive on Proxima b,

fit and free from
radiation damage.

Though hibernation
may help our astronauts

to survive the journey,

we must also ensure
they are able to survive

on the surface
of their new home.

DR. HAWKING: Getting to Proxima
b is only part of the problem.

Although we think it has
similarities to Earth, it is

very unlikely to be exactly
the same as our current home.

The crew may have to adapt
to life in a very alien world.

They will also need
to find water, grow food

and use the
planet's natural resources

to build a
successful new civilization.

NARRATOR: If the
planet we're able to reach

has no breathable atmosphere,
they won't last long.

Thankfully for our explorers,

engineers have been
working on a solution.

♪

NARRATOR: Proxima b
may be the best candidate

we have for a habitable
planet in our neighborhood.

But our latest
observations suggest

that this planet may
not have an atmosphere

that could support humans.

So if we're not able to
find an oxygen-rich planet

that's within our reach,

scientists are
experimenting with other ways

that we might be
able to survive.

This is Biosphere 2.

In 1991, eight people
lived inside these glass domes

in the heart of the
Arizona Desert for two years.

The structure was built
as what is what is known as

a "closed loop," completely
sealed from the outside world.

Everything the humans needed
was provided by the plants.

By photosynthesizing,
the plants produced oxygen

and removed carbon dioxide.

They recycled
water for drinking...

and the edible
plants provided food.

Biosphere 2 is now used
as a huge research facility

for scientists who
recreate and study

the Earth's various ecosystems.

In the miles of tunnels

that sit underground
beneath the greenhouses,

Biosphere's
director, Dr. Joaquin Ruiz,

gives Danielle a
behind-the-scenes tour.

DR. RUIZ: All these things
that you see here to your right

is all the air cooling
and heating that's required

to keep the place alive.

And that's the stainless steel

that is underneath
the whole biosphere

so that there's no
interactions between

the soil and the
biosphere itself.

So the complete thing
was sealed from the top

and it was
sealed from the bottom,

and this is what it
takes to cool the whole thing.

The original experiment
had two reasons for it being.

One of them was trying
to understand in detail

how various biomes
of the Earth operate.

So there's ocean
and a rainforest.

And the other one
was, what would it take

to create a structure that you
would build on another planet

and you could basically live
in it in a sustainable way?

DR. GEORGE: But there's no
way we could actually take

all of this to
Mars, though, is there?

DR. RUIZ: Well, you can't,

but you have to
take something similar.

Because if you're going
to be on another planet,

you're going to have to
deal with its atmosphere.

You're going to have to
deal if you're growing plants.

So yeah, something like this,

or at least the
concepts that are in here

with different materials that
aren't this heavy and so on,

you would have to take.

♪

NARRATOR: The infrastructure
we'd need to sustain

even just a small
number of humans like this

poses an enormous
engineering challenge.

Building something on this scale

would take a huge
amount of time and labour.

And we currently have
no way of transporting

these heavy
materials on a spacecraft.

♪

But at NASA's
Kennedy Space Center,

engineer Rob Mueller
could have the answer.

Robots.

Rob is developing an
army of autonomous machines

that could set up an
entire habitation on Proxima b

before any humans arrive --

starting with
robots that can locate

the raw ingredients
for construction...

right where we need them.

DR. GEORGE: These are
incredible little things then,

aren't they?

ROB: These are what
we call the swarmies,

which is a small robot designed
to mimic the behavior of ants.

And they are very
small, and we will have

hundreds of these on the
surface looking for resources.

In nature the ants go around

and they look for resources
in a kind of a random walk

and they leave a
pheromone trail behind.

What we will do is track

the same kind of
pheromone trail in software,

and then once the swarmies,
which are mimicking the ants,

find the resources,

one of the robots will
raise its hand and say,

"I've found the resource,"

and all of the other
robots will converge

by following the digital trail,

the breadcrumb trail
that we left in the software.

NARRATOR: The swarmies
could find all the resources

we need to support humans...

on the planet itself,

within a surface dust of
crushed rock known as regolith.

ROB: You just drive one
stick, it moves to one side,

the other stick
moves the other side,

so it's kind of
like a tank steer.

NARRATOR: Rob and his team
have developed a mining robot

to dig up this regolith.

DR. GEORGE: So why are
you scooping the surface?

What are you hoping to find
with that surface regolith?

ROB: On the moon, 42 percent
of regolith by mass is oxygen.

So if you need breathing air,

you would simply scoop up
the regolith, process it,

and you are good to go.

DR. GEORGE: Wow.

ROB: Yes, on Mars you
have hydrated minerals,

and you can extract the water
from the hydrated minerals,

and you would have water
for drinking, growing plants,

and you can also
electrolyze the water,

get hydrogen and oxygen,
which is rocket propellant.

And then the waste
material, even that's useful.

You use that for construction.

NARRATOR: Rob's
mining robots would mean

we'd barely need to take any

of these
essential supplies with us.

And even better -- he's
created a fully automated

production line that
transforms the planetary dust

into a mind-blowing
variety of building materials.

ROB: ...
stronger than fiberglass.

This material here is a mixture
of a polymer and a regolith,

so this is concrete for space.

DR. GEORGE: Wow.

ROB: This is rebar, used already
today instead of steel rebar.

It doesn't corrode, is very
strong and it's very cheap.

This is a paver that's in
the shape of a puzzle piece,

and this was done
simply by taking the regolith,

putting it in a mold, and
then you bake it in an oven.

And we assemble
these with robots,

and then we add a landing pad in
space for landers to land on.

Now, can you imagine
launching this into space?

I can barely pick this up.

It makes a lot more sense
to use the local materials

and make it there.

DR. GEORGE: So you
literally could do everything,

literally everything we need
to build a new civilization,

on a new planet.

ROB: Everything is there.

We just need to have
imagination and ingenuity.

We have to
invent new technologies

so that as a civilization,
we can move into outer space,

to have a healthy
future with abundance.

NARRATOR: Visionary scientists
and engineers like Rob

are showing us that
colonizing another planet

might not just be
a futuristic dream.

We are making massive
leaps in rocket technology.

We're understanding how to
protect our bodies in space.

We even understand how
to build a new civilization

millions of miles from Earth.

Some of this technology
may be in its early stages...

but humans have an
astonishing ability

to take new ideas
and develop them into

something far beyond what
we ever thought possible.

DR. HAWKING: Our
species' natural curiosity

is what will drive
us to distant planets.

In the next 100
years, we will embark

on our greatest-ever adventure.

Our destiny is in the stars.

Space, here we come.

♪