01x01 - Space: How Far Can We Go?

[bunniefuu]

For more than a decade, I've made
programmes about the universe...

...and our place within it.

There it is! There it is!

I can see the parachutes.

I've had some remarkable
encounters...

I can't believe you can just stand
next to a spacecraft...

Release...

...memorable experiences...

They came down exactly the same.
Wow!

HE SCREAMS

...and explained
some beautiful science

about how our planet works.

That really is the thin blue line
that protects us.

Look at that!

CHEERING

Now, I'm taking a new look
at those past programmes.

This surely is as close as I'm going
to get to being in space.

I think our knowledge really has
moved on since we made these films,

so it's really interesting

to revisit some fundamental
questions again.

Are we alone in the universe?

What really is gravity?

Where will the exploration
of space take us?

TICKING

And what is time?

BEEPING

Beeping is never good.

I've come to
the Royal Institution...

...the historic home of science,

to watch some my old films.

I'm starting by looking
at a question

that's fascinated me
since I was young.

How far can we go
in our exploration of the cosmos?

The way you acquire
reliable knowledge about nature,

about the universe beyond Earth,
is to go and look, to explore.

I think now we're living through
the beginnings of a new age

of exploration.

Physical exploration
of the universe beyond our planet.

At this point in the 21st century,

for the first time,

space flight is on the verge
of becoming routine.

And I do really think that with
the advent of, particularly,

reusable rockets that fly up
into space,

deliver something
into near Earth orbit,

and then come back down again,

we're on the verge of a golden age.

How far can we go?

I was always interested in space
when I was growing up.

The first thing I really remember
was the first flight

of the space shuttle,
which actually, as I speak now,

was 40 years ago yesterday.

And I remember that
absolutely vividly.

RADIO COMMS:

These things that I saw
on television growing up,

you know, astronauts training
underwater,

or flying in jet fighters...

I never thought I would get
the chance to do any of those.

I am floating in a spacesuit above

the International Space Station.

It's surely as close as I'm going
to get to being in space.

Astronauts have to do this
for hours at a time, six, seven,

eight hour space walks,
they're going to have to perform

many of them to install this module
when it's taken up into space.

Over there,
that's the Zvezda module,

the Russian habitation module
where the cosmonauts sleep,

you know, where they eat -
it's their lounge in space.

You can just imagine, can't you?

If you imagine the Earth stretching
out over there, curving away.

Ahh...

I think it'd be wonderful -
so wonderful.

It's kind of one of those things
you always dream of, you know?

I did, anyway - doing a space walk

out in space on the Space Station.

This is undoubtedly the most
physically demanding thing

I've ever done.

What I learnt, ultimately, is that
I don't have the right stuff,

I have the wrong stuff -
cos it's really hard!

Since November 2nd, 2000,
when the first expedition arrived,

the International Space Station
has been continuously occupied.

HE SPEAKS RUSSIAN

Humanity's permanent outpost
amongst the stars.

You know, for me this defines
what it means to be human.

Throughout the whole history
of life on Earth,

of all the creatures that have ever
lived in the oceans

and the land or in the sky,

only one has ever made it off
its home world.

So, why is it that we alone
have ventured out into space?

What is it that makes us special?

Exploration is important.

It's the way that we acquire new
knowledge about the world around us.

We're part of this world.

And if you think about the world

not only as the surface of our
planet, but the wider environment,

there's a great deal more territory
to explore beyond the Earth

than there is on the surface
of the Earth.

The International Space Station
is the current frontier

for humans in space.

For the last 20 years now,
there has not been one second

when all humans have been confined
to their home world.

The space station has been
continuously crewed

for all that time.

It's a tremendous achievement.

And what we've learned is how
to live and work

and build beyond our planet -

that's the great gift of
the International Space Station.

But exploration doesn't have
to be physical.

We tend to think of exploration
as walking across new terrain

and planting a flag like
the polar explorers of old.

But it doesn't have to be that.
It can also be intellectual.

And actually, for most of history,

our exploration of the universe
beyond Earth has not been physical,

it's been looking up at the stars.

These are the Atlas mountains
in North Africa.

According to Roman legend, they held
the heavens above the Earth.

And they are one of the finest
places to come to view the stars.

From a place like this, it's easy
to appreciate the profound effect

that the night sky would have
had on our ancestors.

You know, from a modern perspective,

astronomy can seem remote
and arcane,

because we've lost our connection
with the night sky.

From a city, you just don't see

a sky look anything like this.

From the darkness of
the Atlas mountains,

it's really truly majestic.

S0, f0!' OUT BHCGStOFS,

the connection with the night sky
would have been incredibly intimate.

They looked into the skies to
understand their place in creation,

and the movement of the stars
told them one thing.

They were at the centre
of the universe.

Up there is Polaris, the North Star,

and it's almost exactly aligned
with the Earth's spin axis,

which means that
as the Earth rotates,

all the stars rotate through the sky
around that point.

So, it looks for all the world
as if the Earth

is at the centre of the universe

and the stars rotate around it.

Of course, that's what the ancients
thought for thousands of years,

and why not? Because it's obvious...

...but wrong.

To understand the Earth's real
position in the solar system,

we need to look at the one set
of bodies that doesn't behave

as predictably as the stars.

The Greeks named them "planetes",
or wandering stars,

and we have kept the name planet
to describe them.

This is Mars, photographed once
a week over a period of months.

Rather than travelling in a straight
line across the background of

the stars, it occasionally changes
direction and loops back on itself.

It's very hard to explain
these retrograde loops

if the Earth
is at the centre of the universe.

Understanding the retrograde motion
of Mars didn't come easy.

That's why it took over 2,000 years
to work out,

but I'm going to explain it
using a stick and some rocks.

The key thing is that the Earth

is not at the centre
of the solar system.

The sun is.

And the Earth and Mars go around it

in almost circular orbits.

So, when Mars is
viewed from the Earth,

then it's seen on the sky.

In fact, on the constellations
of the Zodiac.

So, as Mars orbits around
and the Earth orbits around,

then from that position, Mars will
look like it's there on the sky.

Mars moves and the Earth moves
in that position,

and Mars moves in that direction
across the sky,

and again, in that position,
Mars will be here.

So, you see, it's moving in
a straight line across the sky.

But what happens
when the Earth overtakes Mars?

Then, look at the line of sight.

Mars has moved back to there.

It's reversed its direction.

And it continues to do that
until the Earth

gets round to somewhere like there

and Mars is here, and then you see

the line of sight means that it's
started moving that way again.

So Mars has ex*cuted that strange
looping motion on the sky

because the Earth overtook Mars

on the inside,

and that's why
the retrograde motion happens.

Simple!

Understanding the retrograde loops
was one of the major

achievements of early astronomy.

It created the concept of the solar
system and allowed us to build

the first accurate maps
of the planets

and their orbits around the sun.

You might say, well,

how ridiculous is it to think that
we are the centre of the universe?

But Aristotle had a good
argument for that.

He said, "Well, the Earth
is at the centre of the universe

"because everything falls towards
it, and it's not moving."

That's actually what we observe.

It's a really terrific
intellectual leap to realise

that, actually,
you're on a little ball of rock

careering around a star,

which is itself careering around
the centre of a galaxy,

which is itself careering
through the universe

with trillions of other galaxies.

None of that is obvious.

All of it requires exploration
and thought.

As we continued to explore,

we learned just how vast
the universe is.

The biggest breakthroughs have
happened in the last hundred years.

I think it really was a remarkable
time in the first half

of the 20th century, because in
parallel with the developments

in cosmology, where we're learning
for the first time, really,

that we live in a vast universe -

we're also developing the
technology to explore it physically.

When you think about the rate
of achievement, you know -

at the turn of the 20th century,
no powered flight existed.

Nobody had ever left the surface
of the Earth in anything

other than a balloon.

Technology broadened our horizons.

INTENSE BLAST

And a new breed of explorer
was born.

In the world of space exploration,

this room is hallowed ground,

because every astronaut

that flies to the International
Space Station today, and indeed

pretty much every astronaut
that's ever flown into space,

first American,
then Russian and European,

have sat at this table
and signed this book.

This is so precious.

It's a tradition that began in 1969

with three Soyuz crews,

Soyuz-6, 7 and 8.

As you flick through the pages
you just turn through

the history of space exploration.

And here on a visit,
June 1st, 1970, is Neil Armstrong.

The reason every astronaut wants to
come here and sit at this table

is because this table,

and all the furniture in the office,

everything you see in the office,

belonged to Yuri Gagarin.

This is a great speech.

An unprecedented duel with nature -

could anyone dream of anything
greater than that?

You know, it's easy to characterise
the early astronauts,

the pioneering test pilot
astronauts, as emotionless people.

You know, people who were just
interested in flying the vehicles.

But you only need to listen to
Yuri Gagarin's words to realise that

he knew precisely the significance
of what he was about to do.

On April 12th, 1961,

we became a space-faring
civilisation.

Just being immersed for a few clays
in the Russian space programme,

there's an almost spiritual
motivation -

you can see it in the art.

Alexei Leonov,
the famous Soviet cosmonaut,

did these beautiful paintings...

...which I think had a sense
of that - it's almost like

it's our destiny
to return to the stars.

For me, we,

by which I mean the human race,

are at our best
when we over-achieve,

when we do something

that really, we weren't quite
capable of doing at the time.

And the Apollo moon landings have
to fall into that category.

The fact that you can navigate
a quarter of a million miles

through space and land on
the surface of the moon

and then take off from the surface
of the moon,

re-enter the Earth's atmosphere,

with all the tremendous engineering
challenges that that entails -

aerospace, in my view,
was not really ready to do that.

I think it's just a beautiful
example of engineering overreach.

This most extraordinary quest
to put a man on the moon

required the most
extraordinary rocket.

The thing about the Saturn V is
it's just enormous by any standards.

And the challenge was,
how do you film that?

You can just about,

if you go a long way away
with a big wide lens,

fit it in shot.

But that doesn't tell you anything
about the scale of this thing.

And you realise that it takes you

about two or three minutes
to walk along it,

and so we thought,
"Well, let's do that, then."

But of course, if you want
to do that, then you can't cut.

You've got to have one shot that
tells you the scale of this thing.

This is the spacecraft that took
John Young, Ken Mattingly

and Charlie Duke to the moon.

There's the service module
and the command module,

that's the engine that fired
to bring them

back from the moon to the Earth.

The lunar lander sat inside there

and this piece is essentially
a single rocket motor

that fired to take them
from Earth orbit to the moon.

So, this is the 120 tonne
moon spacecraft, if you like.

But from a physics perspective,
the difficulty is getting

that into orbit.

On Saturn V, that was done
in two bits.

This is Stage Two

and that is the Stage Two fuel tank.

Inside there are 450 tonnes
of rocket fuel

and this burnt through those
450 tonnes in about six minutes,

taking the spacecraft
from an altitude of 200,000 feet,

about 38 miles, up to 114.5 miles,

that's virtually in orbit.

It did that by burning the fuel
in five engines.

Now, at the time,

that was one of the most powerful
rockets ever built,

but not the most powerful.

That was this -

Stage One of the Saturn V.

There are 2,200 tonnes of fuel
in here

and Stage One burnt through that in
about two and half minutes.

To do that, they had fuel pumps
that were more powerful than a 747

at lift off to pump 15 tonnes
of fuel a second

into these...

The F1 engines.

Every statistic about
these engines is ridiculous.

In those two and half minutes,

when this spacecraft
was lifting off,

the power generated was more

than the peak electrical generation
capacity of the United Kingdom.

It's one of my favourite shots
that I've ever been involved in

because it was so, so difficult.

Hi. Charlie.

One of the great honours I've had
whilst filming is to meet

some of the astronauts
who've travelled to the moon.

Hello, Charlie.

Nice to meet you, good to see you.
Wonderful to meet you.

Good to be here with you.
Have a seat.

Charlie Duke was a lunar module
pilot for Apollo 16

and the youngest person ever
to walk on the moon.

OVER RADIO: We're feeling good.

Mission objective, to bring back
samples from the lunar highlands

and test drive new technologies.

Here we go.

We're really going up a hill,
I tell you.

When I was just becoming
aware of Apollo,

I thought that I would be able
to go into...

at least into Earth orbit myself.

Yeah, really.
My dad was born in 1907

and so he was just right
after the Wright brothers

and he could barely believe
that his son went to the moon.

And yet at the time,
my five-year-old, Tom,

he didn't think it was
any big deal, you know,

that everybody in the neighbourhood
was going to the moon.

Bill Armstrong was
a next door neighbour,

Tom Stafford was in
the neighbourhood,

Frank Borman was in
the neighbourhood,

the whole neighbourhood was either
NASA engineers or astronauts,

so for everybody, it's natural,

"Let's go to the moon, Dad,
when are you going to do it?"

OVER RADIO: Hey, this is perfect,
with the rover and you

and the mountains,

and the old flag.

Come on out here
and give me a salute.

Big Navy salute.

Off the ground a bit more.

There we go.

I mean, you're most famous,
probably, for the most famous

photograph involving you
and it's not you -

it's the photograph of your family
that you left on the moon.

Yeah, I asked the boys,
they were five and seven,

I said, "Would you guys like to be
with your dad on the moon?"

They said, "Oh, yeah,
that'd be great, Dad."

So on the back of that picture
we had written,

"This is the family of
astronaut Charlie Duke,

"from planet Earth, who landed
on the moon in April 1972."

We all signed it

and then I dropped the picture
on the moon.

It sort of shows the human side
of space flight and, you know,

we were family men,
we were dads, husbands,

and so wanted my family
to be a part of it.

They'll sit there for millions
of years, those, won't they?

They won't go anywhere.

If you look back to those clays,
so, less than a year from first

test flight, first manned
test flight to landing on the moon.

Yeah.
Would that be possible now? No.

Why?
We don't have the schedule,

the money, to build spacecraft
that quickly.

We don't have the, er...

...manpower to do it.

I mean, 400,000 people and
unlimited budget, you can do a lot.

Yeah. And so that's...

THEY LAUGH

That's what we had.

After Charlie left,
only two men have ever gone back.

At the end of Apollo, early 1970s,

I think most people thought that
we would be back to the moon

quite soon.

Actually, it's been 50 years
and we haven't gone back.

But now we're trying
to re-acquire those skills

because we want to go further.

So, the next step is Mars.

Mars is in our back yard.

It's the most Earth-like place
in the solar system,

other than the Earth,
but by a long way -

it's almost habitable.

So, I think if there is going to be
a new frontier physically,

that we're going to explore,

then there is no choice -
it has to be Mars.

I think the difference between
the future Mars missions

and the Apollo missions is that
Apollo was a national endeavour.

Mars won't be like that.

Now, the visionaries,

the people who are really trying
to excite us

and push us out towards the stars,
to Mars and beyond,

are not only focusing their efforts
on national governments,

they're also focusing on developing
the expertise in the private sector.

Foremost amongst those visionaries

is aerospace engineer
Dr Robert Zubrin.

He's a legend in space geek circles

cos he wrote the books on how to
build a space-faring civilisation,

how to colonise Mars.

Er, OK.

So, here's my lab.

This machine here is
one of the most important.

This is for making rocket fuel
and oxygen on Mars,

out of the Martian atmosphere.

Since the 1990s, Zubrin's proposal
of a lightweight,

"live off the land" approach to
visiting Mars has influenced many,

including NASA.

So, this is really a lab,
aimed at ultimately colonising

and building bases,

creating resources out of raw
material, and staying there.

Yes.

This is...

...my invention for
cleaning clothes in space.

I call it the "vacuum cleaner".

It sucks out all the air.

It boils off all the water
and all the oils.

It explodes all the bacteria.

They're dead.

The stuff is clean.

Some of Zubrin's ideas
may seem unconventional.

But it's his back-to-basics approach
that has proved so appealing.

Can you give us some indication
of the difficulty of humans

going to Mars and then colonising?

Cos you've got these wonderful
paintings on the wall.

This is a depiction of my mission
plan for human exploration

to Mars, which is known as
the "Mars direct plan".

There's nothing in this that's
fundamentally beyond our technology.

We're not talking
about venturing into new

and unknown worlds of physics here.

We're talking about brass tacks
engineering.

Building systems of moderate size,

flying them to Mars.

We do not need giant
Battlestar Galactica spaceships.

How optimistic are you that this
is something different now,

in 2017, to the way the world was
in, let's say, the year 2000?

In the year 2000,
we knew about people like Elon Musk.

They were characters
in science fiction stories,

of the entrepreneur who would
come along and make this happen.

Well, now those characters
have stepped out

of science fiction novels,

and they are now in the real world,
doing this stuff.

Zubrin's zeal for finding
a way to reach Mars

is driven by a belief that it is
the only option humanity has

to ensure its long term survival.

The worst idea that anybody
has ever had

is that there is only
so much to go around, OK?

And that therefore, nations are all
enemies of each other.

If we can get off this rock

and see that the world we live in
is not this planet -

this is not the world,
this is just one planet

in a world of trillions
of planets -

and that there are unlimited
resources available to us

if we maximise the reach
of human creativity.

And therefore,
every nation is fundamentally

the friend of every nation, and
every person of every other person.

Zubrin has a view
which I share, actually.

Which sounds ridiculous
when you first vocalise it.

How do we grow our civilisation
without destroying our planet,

without destroying ourselves?

He takes it as read
that we have to expand.

I don't see that our future,

for the indefinite future,

can be just based on being
more and more careful

with dwindling resources
here on Earth

when, as Zubrin points out,

there are unlimited resources
available beyond Earth.

I think, inexorably,
the logic leads up there.

Zubrin's ideas have influenced
a new kind of space explorer.

Billionaires,
like Elon Musk and Jeff Bezos,

are building rockets.

They see Mars as
the next great frontier

and space exploration as
the saviour of our civilisation.

I remember speaking to Jeff Bezos,
which was a real privilege.

So, he says he wants
to zone the Earth residential.

That sounds ridiculous, doesn't it?
"What are you talking about?"

But, of course,
if you have a paradise island

in the middle of the Pacific Ocean,

you don't decide to build
a steel mill on it. Right?

Well, the Paradise Island
is the Earth.

And so, where should
the steel mills be? We need them.

Ultimately, the vision is to have
the dirty heavy industry stuff

up there, where all the resources
and all the energy are,

and keep this place pristine.

Steel mills on Mars might sound
like science fiction,

but NASA is developing machines for
mining and building on other worlds.

The moon is seen as
a stepping stone to Mars.

One day, robots will mine
the lunar surface

to build habitats
for human settlers.

One stick drives
one side of the wheels

and the other stick drives
the other side of the wheels.

Robotics engineer Aj Nick is
letting me take one out for a spin.

So, we can turn on this button.

You can go ahead and raise this arm
over here, and keep driving.

There is a real feeling of
stability there, and...

Ha-ha-ha!

You're confident I can't break this?

I have done way worse to this robot.

I suppose the obvious question is,
if you want to mine this,

why don't we just get a shovel
and dig it up?

Why is the robot so complicated?

The first problem is,
we're trying to make

everything as lightweight as
possible, to fit inside of a rocket.

And then you get there on
the lunar surface,

and you have reduced gravity
once you get there.

So, now the thing that was
already really light,

because you had to make it light
to fit in the rocket,

is even lighter
while it's there on Earth.

OVER RADIO: This is really
some rock. Really shocked.

With one sixth of Earth's gravity,

operating on the moon creates
a challenge.

I'm going to explore right here.

While the Apollo astronauts
could move around with ease,

they found simple tasks like digging
and collecting rocks difficult.

Argh!

Current Earth terrestrial excavators
actually get their

excavation force, their ability
to cut through the soil,

from the weight of their vehicle.

Here, since we don't have a lot
of weight, it's very difficult.

Aj and his team have come up
with a unique design,

that will allow their robots to work
in the moon's weak gravity.

So, now I'm digging.

The scooping drums at either end
rotate in opposite directions.

This has the effect of pinning
the robot to the ground,

allowing it to dig
without floating off into space.

As one drum on the front is digging,
the other drum is rotating

in the opposite direction
from the other drum.

And so, that allows the excavation
forces to be cancelled

as it's digging.

This is the only vehicle
in the world that can dig

more than its own weight.

If I took it into this trench the
wrong way, it may well fall over.

Can I do that? Yep.

Oop!

Unlike other planetary rovers,

these robots are meant to be robust,

designed to get themselves
out of problems,

even if they're flipped upside down.

It's really easy to drive,
and really manoeuvrable,

and really powerful.

It does seem like you can get out
of a lot of trouble.

Once the lunar dirt has been dug up,

it needs to be transformed
into a building material.

I'll show you some materials here.

Senior technologist Robert Muller
has been sintering the lunar dust,

heating it until it solidifies.

So, the result,
a well sintered regolith, is this.

And that's essentially turning
crushed rock back into solid rock.

That's really quite heavy actually,
that feels quite dense.

So, that is just this material
in an oven, essentially.

That's right.

By mixing the regolith with plastic,

Rob can create something
far more versatile,

a material which can be used
in a 3D printer.

And we use the big robot arm,
we have a print head on it,

and then we are able to make
objects like this.

This is a blast deflection wall.

This is an ogive dome.

It could be used for the roof of
a habitat when it gets really big.

And in fact, it's quite strong.

If you look down at it,
it's very strong.

You can kick it all day long
and it won't break. That's quite...

So, that is built by that robot?

Yes.

Using, essentially, the regolith
that you would find on the moon?

That's correct.

So you never bring any
materials from Earth.

You go mine them on the moon,
and then you build whatever you need

to create your local moonbase
out of local materials.

All you have to bring is the robot.

Everything is there, is the point?

Everything is there,

the only two things missing
are technologies and imagination.

If we can put
those two things together,

and harness the materials
and the energy we have in space,

we have all the resources
in space we need.

We just need to be clever enough
to learn how to use them.

The plan is to use the moon
to learn how to colonise Mars.

So, landing on and then,
in the future,

colonising Mars
is tremendously exciting but,

and it seems ridiculous to say it,

but it's worth reminding ourselves,

there are going to be
tremendous challenges.

Get it!

BRIAN LAUGHS

These are the dunes
in the Namib Desert.

It's an absolutely
spectacular place.

This place is not the hottest or
the driest desert in the world,

but these dunes are some of
the oldest sand dunes in the world.

And the reason we're here
in the Namib Desert is that this is

a great analogue
for the surface of Mars.

This is what the surface
of Mars looks like,

and these dunes,
called barchan dunes,

these crescent shaped dunes,

are the same as the sand dunes
on Mars.

So, if you want to get a feel
for what it would be like

on the surface of Mars,

and you want to know what driving
a 4x4 around on it would be like,

then this is the place to come.

Mars has vast dunes...

"GHOFITIOUS VOICGHOGS...

...and giant ice sheets.

It has canyons and river valleys.

Mars is a dry, frozen version
of our home,

covered in red dust and sand,

and it's all due to the fact that
Mars has virtually no atmosphere.

Mars is not a nice place.

You have problems with radiation,
you know,

very limited magnetic field,
virtually no magnetic field,

so very little protection
from solar radiation.

It's cold and it's barren
and it's arid.

The problem with humans is that
they're quite fragile things

and we need a big infrastructure,

a life support system
to colonise Mars.

And that's really difficult.

It is at the limits
of our current technology.

So, if we want to explore
the universe beyond Earth...

...it is simpler to do it
with robot explorers.

Sending robotic probes in our place
has allowed us

to explore deeper into the cosmos
than we could ever go.

TYRES SCREECH

CAR HORNS BEEP

In the last 50 years, we've sent
unmanned space craft to every

corner of the solar system.

No, no, no, no!

HORNS BEEPING
Tram!

Many not much bigger and not much
more advanced than this car.

Whoops, sorry.

So this is the most dangerous
thing I've ever done.

I've flown in jet fighters,

I've dived to the bottom
of the ocean,

I've been astronaut training
in Russia, zero G flights,

but nothing was as dangerous
as driving a vintage Fiat 500

around Rome in rush hour.

It's a beautiful piece
of engineering

but it's essentially got no brakes.

We sent Mariner 10
and Messenger to Mercury,

the closest planet to the sun.

It's got no acceleration.

I don't know what these sticks
do here.

43 missions to Venus...

...and 51 to Mars...

AGGRESSIVE HORN BEEPING
Wa-hey!

...but only a handful have made it

into the solar system's
outermost reaches.

In 1977, a chance alignment of the
planets meant that it was possible,

at least in principle, to launch
a spacecraft to all four

of the outer gas giants,

so NASA launched two spacecraft -
Voyagers 1 and 2.

Just 18 months later
they reached the largest planet

in the solar system, aptly named
after the Roman king of the gods,

Jupiter.

They explored Saturn...

...before separating, with
Voyager 2 going on to visit Uranus.

And then in 1989,

after travelling for 12 years...

...it reached Neptune -

the most distant planet
in the solar system.

When I was growing up
I had this book, which is a book

into which you stuck cards

that you collected
in packets of tea, right,

and this particular book
is The Race into Space.

And I loved this.

You can see how long it was ago
cos it was 5p.

This is in the early 1970s.

Right at the end, one of the future
missions is the grand tour

of the solar system,
because it was known that

if you launched a spacecraft
in the late 1970s,

there is a chance planetary
alignment

which means that you could send
a single spacecraft

to Jupiter and Saturn and then
to Uranus and then to Neptune.

And this became
the Voyager programme,

Voyager 1 and Voyager 2.

Voyager 1 is the furthest artefact
of our civilisation.

Right out there.

Twenty two thousand million
kilometres away!

It's been in space
for over 40 years.

It's almost incomprehensible,

and it's even more incomprehensible
that we're still in contact with it.

And in my favourite book,

from when I was growing up,

there's a picture -
the Goldstone Mars station.

And so, it was almost like the
fulfilment of a childhood dream

seeing it on the horizon.

I had this book with me.

I got it out and looked and went,
"Yep, there it is."

Today, the Goldstone Station
is listening out for the faintest

whisper from Voyager 1.

Call 233.

It's almost there now

so we should be
seeing it coming in.

Voyager is so far away

that it takes the signal
around 15 hours to arrive,

travelling at the speed of light.

Now we've got the receiver.

Oh, that triangle?

Yeah, that's it, right there.
There it goes.

Yeah, yeah.

It may appear as little more than
a blip on a screen but, for me,

it's beautiful.

I mean, you just have to think
about it, this little thing,

it's no bigger
than a double decker bus,

designed in the late '60s,

launched in the mid '70s,

and still functioning
32 years later.

Good science data is still coming
out of that little spacecraft.

I think it's absolutely wonderful.

This was a wonderful thing
because it was real.

And after all those years
that I'd followed this spacecraft,

you can see, right, in my face,

just absolutely,

completely forgot that I was making
a television programme.

And just got carried away
by the moment.

Just wonderful.

Voyager1 is now
in interstellar space,

14 billion miles from Earth.

After photographing the outer
planets of our solar system,

Voyager took this image.

Known as the pale blue dot,

it's the most distant image
of our home planet ever taken.

Earth as a single pixel.

And after more than 40 years
of exploring space

we still receive a signal
from Voyager 1.

Elsewhere in the solar system,

another world awaited our arrival.

New Horizons, for me, is probably
the most exciting mission

that's been mounted in the last,
certainly several years,

perhaps decades, because it was
a mission to a new place,

to a new world and that world,
Pluto, we knew nothing about.

And that's exploration at its best.

It's always the case
that if you go somewhere new

that you've never been before,
you make unexpected discoveries.

And New Horizons did not disappoint.

After nine years of flight,

New Horizons awoke.

ARCHIVE AUDIO:

CHEERING AND APPLAUSE

We had our first glimpse of the most
distant world ever visited.

Pluto is beautiful.

Far from being a frigid,
featureless world,

it turns out that it has all
the characteristics of a dynamic,

living planet.

Yes, it is cold on the surface,

about -230 degrees Celsius.

I'd be walking over solid nitrogen.

But the blotches
that could be made out

in the grainy
Hubble Space Telescope images

turned out to be
a tremendous variety

of geological form and structure.

But by far the most
recognisable feature

is the region known as
Tombaugh Regio,

or to give it its more popular name,
Pluto's Heart.

But there's something
very strange about the region,

something that sets it apart
from the rest of this dwarf planet.

The surface of Pluto is covered
in craters - the scars of impacts

that have taken place over
many billions of years

just like the surface of our moon.

Except, if you look
on Sputnik Planitia,

it is absolutely smooth.

There are no craters there at all -
not a single one.

Detailed imagery
beamed back by New Horizons

revealed a network of
hexagon and pentagon shapes...

...that crisscross the frozen
nitrogen surface.

A clue to what might be happening
can be seen in these images.

Those kind of patterns are found
elsewhere in nature.

Here, for example,
on the surface of the sun.

Or here, in a liquid that's been
heated from below.

These patterns are characteristic
of convection.

There's a heat source, which is
causing material to rise up

and then it cools
and falls back again.

And in those circulating
convection currents,

you tend to get patterns like this.

So, what could be happening below
the surface of Sputnik Planitia

is that there is a heat source
deep down which is melting

the nitrogen ice and causing it
to rise, cool, and then fall again.

And those convection currents
are constantly resurfacing the area.

Our best theory of how
this could be is that somewhere

deep in its interior...

...there are radioactive elements
that generate heat as they decay.

Now, the evidence from
Sputnik Planitia that there's still

an internal heat source

and studies of other geological
features on Pluto

have led some scientists to suggest

that that ocean of water
might still be there.

And the relatively warm ocean
could explain

the lack of craters
on Sputnik Planitia.

The entire area is constantly being
repaved as the nitrogen surface

is slowly turned over.

Imagine that, an ocean,

billions of miles away from the sun,

on the frozen frontier
of the solar system.

On this most surprising of worlds,

there may still be
an ocean of water.

How far can we go?

With our current technology,

there are rough designs
to build spacecraft

that can go to the nearest stars.

The nearest star,
the Alpha Centauri system,

is about four light years away.

That's a tremendously long
journey...

...but it's a journey,
with current technology,

that we could imagine making
in 100 years, let's say.

Is there a limit to our exploration?

Well, there may be limits
to our physical exploration,

but there are no limits
to our intellectual exploration.

In our imaginations,

using science to travel,

then we can explore out to the edge
of the observable universe.

So, I would say there is no limit

to the potential
of human exploration.

Why do we feel the need
to continue to explore?

There's a deeper question here
which goes to the very heart

of the question,
what does it mean to be human?

One of my favourite quotes,
TS Eliot.

He speaks about exploration.

He says, "We shall not cease
from exploration.

"And the end of all our exploring

"will be to arrive where we started

"and know the place
for the first time."

I always think of the pale blue dot
image that Voyager 1 took.

That pixel is the only place
we know of in the universe

where life exists.

It is our responsibility, therefore,
to protect this pixel

and not to fight over it.

So, exploration gives us
perspective.

And that's what Eliot means.

In order to understand your place,

in order to be able to comprehend
your importance

and the beauty and privilege

of our position here
in the universe,

you have to go away
and look at that place from afar.

And that, to me,
is the true value of exploration.

Next time, I'll be asking one of
the most profound questions.

Are we alone in the universe?

We have hope that someday,

we will be in the right place
at the right time.

A 72-second flash of radio waves.

This has become known
as the "wow signal".

See you in eight hours.