Original subtitles

♪

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.

♪