All language subtitles for A.Travelers.Guide.to.the Planets.S01E01.Jupiter.2010.1080p.BluRay.DD5.1.x264-c0kE_track3_[eng]

MAN: T minus 40 seconds.
Everything looks good for launch.

NARRATOR: Life feeling
a bit ordinary?

Travel choices a bit tame?

Head beyond the asteroid belt
for an out-of-this-world experience.

Welcome to Jupiter...

home of high-adrenaline adventure.

Plunge into its mysterious depths.

MAN: You'd drop through the clouds,

it would get darker and darker
and hotter and hotter.

At the center, the temperatures
are hotter than the surface of the sun

and the pressures
are unimaginably high.

NARRATOR: Stormy on the inside,
and stormy on the outside.

WOMAN: | like to watch
hurricanes on TV...

pbrrr...you know.

The Great Red Spot being
the biggest hurricane that we know of

and it having been there
for 400 years,

to see this would be pretty cool.

NARRATOR: Want more bang
for your buck?

Thrill-seekers should head to lo,

Jupiter's exotic moon
of fire and brimstone.

MAN: To see lo just blasting off
these huge volcanic plumes,

covered in glowing volcanoes.

It would be a pretty amazing
place to see.

NARRATOR: Escape lo's hot zone

with a dive into the ice-covered
alien ocean of neighboring Europa:

just the place for a close encounter
of the weirdest kind.

MAN: Is there a reason
to go to Europa?

You bet.

It's a totally unexplored world,

and it probably has the highest
probability of life off this planet.

NARRATOR: Choose Jupiter,
and a change of scenery is guaranteed.

With its 62 alien moons to explore,

out here, there's something
for everyone.

Tempted?

There has never been
a better time

to take a giant leap to where
no human has gone before.

To follow in the footsteps
of our robot pioneers

and explore the planets
of our solar system.

MAN: Oh, man, that's incredible!
My golly, this time goes fast!

NARRATOR: A tour of the solar system
wouldn't be complete

without a visit
to its largest planet.

But with the grandest sights,
biggest dangers,

and greatest mysteries
all on the itinerary,

it pays to brush up
before blast off.

Consider this your personal guide
to exploring the kingdom of Jupiter.

Enter the court of an alien giant.

JOHN SPENCER: Jupiter is one of the most
spectacular places in the solar system.

If you are approaching
by spacecraft,

you could see from a long distance
the cloud patterns of Jupiter,

its incredibly complex,

constantly changing
multicolored clouds

that are like nothing else
in the solar system.

NARRATOR: Jupiter takes its name
from the Roman king of the gods.

Fitting for the brooding and mysterious
king of the planets.

Calling it the biggest planet
in the solar system

doesn't do it justice.

Jupiter is a world so roomy

that it could swallow every
planet and moon in the solar system

and still have room for more.

ANDY INGERSOLL: If you move the Earth,
you could put it inside the Great Red Spot,

which is the largest storm there,

and there are several other spots
that are about Earth's size.

So everything on Jupiter is big.

TORRENCE JOHNSON: You can fit
a thousand Earths inside Jupiter.

It's huge, and yet it's quite,
quite under dense.

It's made of almost entirely
hydrogen and helium.

NARRATOR: This giant gasbag is built

from the flimsiest materials
in the universe,

but for all its squishy bulk,
it's a great little mover.

Jupiter spins at such breakneck speed
that it bulges at the equator.

So fast, in fact, that a day here
lasts less than 10 hours,

the shortest of all the planets.

Our gaze was first drawn to the attractions
of Jupiter 400 Earth years ago

when Italian astronomer Galileo
pointed his telescope toward the planet

on January 7, 1610.

His curious novelty quickly became

one of the most powerful
scientific instruments of all time.

And turned our world on its head.

SCOTT BOLTON: What he saw
for the first time

was that Jupiter had four moons,

and he could see those four moons
were going around the planet.

And this is what really first told him

that the Earth couldn't possibly
be the center.

Here were objects going around
something other than the Earth.

NARRATOR: It was a revelation.

lo, Europa, Callisto and Ganymede.

Were these worlds like our own,
circling a distant master?

It's a cosmic experience anyone
with a backyard telescope can have.

Point at Jupiter,
and you'll see for yourself.

DAVID LEVY: Jupiter is like a little
miniature solar system by itself.

It has many moons, four of which
are very large and bright,

the rest of which are
very small and faint,

but these moons are all different.

NARRATOR: The court of the king
of the planets is crowded.

At last count, an entourage
of 62 moons was in attendance.

All dancing to Jupiter's
heavy gravitational tune.

It's even crowned by a trio
of faint gossamer rings.

Jupiter is a planet that knows how to exert
its influence on the solar system.

And how to impress
even the seasoned traveler.

You can fly around the Earth
in a jumbo jet in less than two days.

Try this on jumbo Jupiter

and you'll be in the air for 3 solid weeks,
refueling about 50 times.

Not only will you get sick of the food,
there's nowhere to land.

JOHNSON: You don't actually have
a surface of Jupiter.

You shine a big, strong
radar pulse at Jupiter,

and what you get back
is four tiny blips.

You see the moons of Jupiter just fine.

In fact, we can study them by radar.

Jupiter isn't there.
It's like a stealth planet.

If you had radar eyes, you'd wonder
what these things were circling.

NARRATOR: For a stealthy planet,

Jupiter makes a big blip
on the space travel radar.

And it's a target worth the trip.

The best way to test fly
a trip to Jupiter

is to retrace the extraordinary journey
of the only spacecraft to orbit it.

WOMAN: And liftoff of Atlantis and
the Galileo spacecraft bound for Jupiter!

NARRATOR: Launched by shuttle,

the Galileo spacecraft
left Earth in 1989

for an odyssey that lasted 14 years.

The first three were spent simply
trying to leave the neighborhood

with enough speed
to go the distance.

Three times farther than Mars,
about half a billion miles,

the road to Jupiter is a long one,
with a few bumps along the way.

MAN: Asteroids!

ANNOUNCER: You are there
as they brave the staggering shudder!

NARRATOR: Halfway there
you bump into the asteroid belt.

SPENCER: It's not like in the movies

where you're dodging asteroids
at every second.

Space is very big and the asteroids
are a long distance apart,

so you could travel through it
quite safely.

NARRATOR: The next thing you run into
you can't avoid:

the leading edge
of Jupiter's magnetosphere.

It's invisible, but the sound
is like a signpost.

CLAUDIA ALEXANDER:
It's like you hit something,

so you're "doo doo doo da doo,"
then "bam!"

And so, oh, now we're
in the Jupiter system.

NARRATOR: Want to explore further?

Be warned: you have just
crossed the threshold

into the most hazardous piece
of space real estate in the solar system.

ALEXANDER: At Jupiter's magnetosphere there's
almost nothing that can protect you.

That's a kind of a "don't enter
this zone at any costs,"

and if you, do you better be prepared
to pay in terms of your electronics.

You know, you are toast.

NARRATOR: Step inside
Jupiter's raging magnetic field

and you enter a radiation hot zone
of staggering intensity,

where incoming charged particles
from the sun

are whipped into a relativistic frenzy.

Buffeted by the solar wind,

the magnetic maelstrom streams back
almost as far as the orbit of Saturn.

ALEXANDER: The magnetosphere of Jupiter
is the largest thing in the solar system.

If it were visible from the Earth,

it would be the size
of the full moon in the sky.

NARRATOR: This was like
a magnet to NASA,

setting off for deep space for the first time
in the early 1970s.

JOHNSON: What Pioneer told us
was that Jupiter's radiation belts

were even more intense
than we had anticipated,

and that meant that
our next mission, Voyager,

suddenly went into rework real fast
to put more shielding on board.

Shields up, captain,

‘cause we knew we were going to be
getting a lot of radiation dose.

NARRATOR: When the space-hardened Voyagers 1 and
2

flew past in 1979 on their way
to the outer solar system,

Jupiter's great mysteries
only deepened.

How were these powerful magnetic storms generated
inside a giant ball of gas?

Why was one moon
boiling with volcanoes,

while its neighbor
remained covered with ice?

And what lies
beneath Jupiter's clouds?

It was Galileo's mission
to investigate.

ANDY INGERSOLL: I'm a weatherman.

| like weather at all altitudes,

from hurricanes near the ground
to weather at the top of the atmosphere.

NARRATOR: Jupiter is
a weatherman's dream:

Furious jet streams blow
alternating bands of clouds

in opposite directions at speeds
of over 300 miles per hour.

Lightning that's ten times
more powerful than on Earth.

Hailstones that could be
the size of footballs.

It's wild out here,
but surprisingly predictable.

INGERSOLL: We can make
a weather forecast for Jupiter

more successfully than we can
make one for the Earth.

If you want to take close-up images
of the Great Red Spot,

you'll have to know where
the Red Spot's going to be

two or three weeks in advance.

Now you could never do that
with a storm on Earth,

but it was not difficult on Jupiter,

because the Red Spot
is so well behaved.

It just chugs along.

NARRATOR: Jupiter's famous
red beauty spot had been a puzzle

ever since it was discovered in 1664.

This seemingly perpetual storm
is more like a giant eddy,

caught between rivers of cloud,
than a hurricane.

INGERSOLL: If you were floating
in a balloon in the center of the red spot

it might be rather calm.

But you'd be going fast.

Your balloon would be going
faster than hurricane winds,

but it might be a smooth ride.

NARRATOR: This storm
is a sight to behold,

towering five miles into the sky,
but why the color?

JOHNSON: Understanding
the colors of Jupiter,

which were one of the first things
noted by astronomers

a couple of hundred years ago,

still eludes us in terms
of a detailed explanation.

NARRATOR:
The other unsolved puzzle

since the Voyagers beamed back
the first weather reports

is why there is a red spot at all.

INGERSOLL: We sort of expected,
as we got close,

things would be rather quiet,

because how could a storm last
for 300 years?

But in fact it was more turbulent,
and that raised the mystery.

How can a storm last for so long?

NARRATOR: Hamid Kellay grapples
with this part of the problem

in a very down-to-earth way:

blowing miniature Jupiter bubbles
in his lab in Bordeaux.

KELLAY: The red spot is huge.

You can put two to three Earths in it.

So everything is telling us
that things like this

should be just annihilated
by the turbulent flow around them.

NARRATOR: By heating a half soap bubble through
contact with a metal surface,

he mimics how the thin fluid
atmosphere of Jupiter

might respond to heat rising
from deep inside the gas ball planet.

Sure enough, swirling storm patterns
emerge spontaneously.

KELLAY: The interest in the soap bubble,
at least this one,

is that we get single vortices
that generate.

We don't do anything
to generate them,

and they just nucleate
out of the blue, basically,

out of the turbulent motion
around them.

NARRATOR: Space agencies
spend billions of dollars

to send spacecraft
to look at these things.

Hamid Kellay's approach
lets you explore Jupiter

without leaving your bathtub.

There's only so much, though, you can
resolve from a safe distance.

To get to know the planet's
heart and soul,

you'll need to take the plunge.

Picture a suicide dive
into the mysterious depths?

Relax.

Galileo's already done it for you.

JOHNSON: We separated the probe
from the Galileo mother ship.

We were flying in toward Jupiter,
basically a ballistic bullet.

INGERSOLL: The Galileo probe
went in at an unbelievable speed

because Jupiter's gravity
just accelerated it on the way in.

JOHNSON: Now you've seen pictures

of meteor fireballs
in the Earth's atmosphere.

Well, this is hundreds of times worse
in terms of the heat and shock.

It was more like sitting
in front of a nuclear blast.

NARRATOR: The violence
lasted only minutes.

On December 7, 1995,
the probe dropped through alien skies

at about 60 miles an hour
and with all instruments blazing.

JOHNSON: In terms of what
it might look like,

it's not dissimilar to the upper
atmosphere of the Earth.

If you were descending
along with the Galileo probe

and looking out the window,

you would see some
thin cirrus clouds go by,

then you might see some other clouds
that might be somewhat strange.

NARRATOR: But it would be like dropping
into an alien chemical factory.

These clouds not only look strange,
they really stink.

INGERSOLL: You have more than one
substance forming clouds on Jupiter:

ammonia, which is cleaning fluid,

then H2S, which is the rotten egg gas.

And then below that is water.

NARRATOR: Like giant thunderheads,
these deep water clouds

are the source for Jupiter's
ferocious lightning.

Things are getting hotter now,
and the pressure's heavier.

Then the clouds end.

JOHNSON: If you imagine going
through the cloud decks of Jupiter

and emerging from underneath
the base of the water clouds,

it would be like breaking out
into clear skies

in descent on an airliner
on the Earth.

NARRATOR: This could be
the most terrifying sight

in the solar system:

clear skies above a bottomless pit,

an infernal drop into the depths
of Jupiter's endless sky.

INGERSOLL: You may have
raindrops evaporating

into the hot interior of Jupiter,

but there's no ocean down there,

there's nothing but just hot,
more hot atmosphere.

NARRATOR: Transmission was lost
about 100 miles below the cloud tops.

JOHNSON: Just hours after
we lost contact with the probe

it descended into part
of the atmosphere

where the probe material itself
would have started evaporating.

So in sort of a Zen closure,

our atmospheric probe became part
of the atmosphere it was studying.

NARRATOR: Heroic as the descent was,

the probe penetrated only
the outermost onion skin of Jupiter.

Peel back the layers
that Galileo couldn't reach,

and the mysteries deepen.

We must now travel
to the very strange heart of Jupiter

to answer a true cosmic puzzle:

how a gas giant is born.

There is no boundary to run into,
no concrete surface,

but far below the clouds,
the pressure squeezes hydrogen

from a hot gas atmosphere
into a hot liquid ocean.

It's deep.

Keep going down
another 12,000 miles

and the liquid transforms again
into something even stranger.

JOHNSON: Temperatures and pressures
would get to the point

where protons lose track of electrons
and nuclei lose track of their electrons,

and you basically just have
a kind of ionic soup,

which is very hard to imagine.

It's just like trying to imagine yourself
being inside a star, basically.

Hydrogen, for instance, goes
into what we call a metallic state.

It is the electrically conducting fluid

that's causing Jupiter's
immensely powerful magnetic field.

NARRATOR: This vast, secret ocean
of seething metallic hydrogen,

not a molten iron core,

is the powerhouse generating
Jupiter's dangerous energy shroud.

But there is one more mystery
hidden inside this giant alien onion:

the key to the origin
of the planets themselves.

400 years after Galileo
first trained his telescope on Jupiter,

Scott Bolton is following
in his footsteps.

Scott is tour director

for the next spacecraft
to pay the planet a visit.

The Juno mission,
launching in 2011.

SCOTT BOLTON: Juno is taking the next step
beyond what Galileo first showed us,

which is the telescope
to look at the outside,

and we've come up with ways
of looking at what's inside of Jupiter,

and from this, we'll understand
how it was built

and how it came to be.

NARRATOR: From what we understand,
the planets formed

from the disc of gas and dust
swirling around our newborn sun.

Matter collided with matter.

It was a game of gravitational
survival of the fattest,

a race that Jupiter ultimately won.

Planets, like people, are what they eat.

Did Jupiter gobble up most
of the abundant lightweight gases first,

before all the solid stuff
started banging around?

Or did it form like
all the other planets,

but grab more than its fair share
of ice and gas from the cosmic chiller?

The molecules of Jupiter's first meals--
rocks, ice, vapors or dust--

are still trapped somewhere inside.

When the Galileo probe measured

higher levels of rare and heavy gases
than anyone was expecting,

things got more complicated.

BOLTON: That did not fit any theory
of how the planets were made.

And so in one quick swoop of time,

all the theories of how
the planets were made,

including the Earth,
went out the window.

NARRATOR: Juno will continue
where Galileo left off,

trying to unravel the mystery
of Jupiter's formation.

BOLTON: We do this by looking
down deep in Jupiter

and understanding first

whether there's a solid core
in the middle of it.

NARRATOR: If gravity measurements
show no solid core,

then Jupiter formed early,
like the sun.

With a core, then its birth came later,
once solid materials were created.

By measuring water content,
Juno should also reveal

how hot the solar system was
when Jupiter formed.

And where.

Some theories suggest the planet
muscled its way in

to be closer to the sun.

With gas giants like Jupiter being
discovered now all over the galaxy,

resolving the puzzle of its origin
is taking on a whole new significance.

While the atmosphere probe
was disappearing into clouds in 1995,

Galileo itself skimmed past moon lo,
put on the brakes

and slipped into orbit
around Jupiter.

Even at this stage,
the team knew that lo,

about the same size
as our Own moon,

would be one of their
prime attractions.

This strange pizza-colored moon

orbits the closest
of Jupiter's big four moons,

and it's volcano central.

JOHNSON: This is one of those cases
where the headline for the daily tabloid

is actually correct:

it's the most volcanic place
in the solar system.

There isn't any place on the surface
where you're not going to find a volcano

within 100 miles or so,
usually less.

And there's enough material
coming out of those volcanoes

to cover the surface over to a depth
of a centimeter every year.

NARRATOR: Fresh-faced lo
has a makeover between every visit.

No other world masks its age so well.

SPENCER: We were lucky enough
to point at a volcano

that happened to be having
a major eruption at the time.

We saw this line of fire fountains,

actually so bright that they
overexposed the camera

and produced a very dramatic evidence
of just how active lo is.

NARRATOR: Take a night flight,
like Galileo's, over the surface of lo,

and the view down to the churning lava lakes
would be unforgettable.

Imagine, then, a visit to the surface.

JOHNSON: The landscape
might look quite a bit

like a red and yellow sulfur-painted
version of what you would see

if you went to the big island of Hawaii,

with the interesting additions of the fact
that you have a very low gravity field

and these geyser-like eruptions
of sulfur dioxide gas,

which give you a kind of a spray
of condensing sulfur dioxide crystals

rising up in 100-kilometer-high
umbrella-shaped plumes

and falling back down to the surface.

NARRATOR: Giant plumes,
a snowfall of sulfur,

fire fountains of lava,
some even hotter than lava on Earth.

Just why is lo cooking inside?

JOHNSON: The reason for lo's
tremendous volcanic activity

is energy that's being pumped into it
from the tides raised by Jupiter.

I'm not talking about liquid tides
like out here in the ocean.

I'm talking about the whole body of lo
is being squeezed by tidal forces.

So every day the surface of lo
at the equator

when it's closest to Jupiter

will be maybe 100 meters higher than it is
when it's furthest from Jupiter.

That's an awful lot
of squeezing and pushing.

NARRATOR: lo is like warm putty
in Jupiter's gravitational hand.

Adventure travelers take note:

a trip out here comes with
some pretty hefty health warnings!

JOHNSON: Io's got
a very, very tenuous atmosphere,

mostly of the gases that are
coming out of volcanoes.

So it wouldn't be a very nice place.
There's basically no air to breathe.

It probably would look
very beautiful

if you could get away
from the discomfort

of sitting there at
minus 300 degrees Fahrenheit,

having to protect yourself from that

and also being given a pretty hefty dose
of radiation that would be lethal.

NARRATOR: Gas escaping into space
from the plumes

is energized by Jupiter's
magnetosphere,

creating an intense band
of ionizing radiation

that bombards a surface
already soaked in emissions.

JOHNSON: If you went out
relatively unprotected

with like a normal spacesuit
from our space programs these days

and walked out on the surface,

you'd get a lethal dose
of radiation in minutes.

[Geiger counter clicking]

NARRATOR: There is one corner
of the Jovian system

where you could find
some unexpected protection

from Jupiter's dangerous
space weather.

Ganymede, the largest moon
in the solar system,

comes complete with
its very own force field.

SPENCER: There's something
happening in the interior

that is active enough
to generate electrical currents

and produce a magnetic field.

ROBERT PAPPALARDO:
Ganymede's deep interior

is probably hot today,

and we know this
because Ganymede

has its own internally generated
magnetic field,

which says that it has an iron core
that's hot and convecting today.

NARRATOR: Sitting safely
under Ganymede's magnetic umbrella

is a good spot to gaze up
at Jupiter's amazing non-stop auroras,

100 times more powerful than Earth's.

ALEXANDER: | think it would be
a pretty beautiful sight

from my position on Ganymede.

Perhaps I'd have
a drink in my hand.

| might be able to see
this spectacular oval

unfolding in a dynamic, you know,
vista right in front.

That would be pretty cool.

NARRATOR: From Ganymede

you also see the last of Jupiter's
big four moons, Callisto.

JOHNSON: Callisto has kind of been

the dull, boring Cinderella
satellite of the system

ever since we saw
its dark, pock-marked,

very heavily cratered
ancient surface.

NARRATOR: The battered surfaces
of Callisto and Ganymede

reveal a darker side

of living in the same cosmic neighborhood
with a giant like Jupiter.

LEVY: I would like
to visit Jupiter one day.

| think it would be a good place
to take a vacation,

but not in July of 1994.

That would have been a terrible time.

NARRATOR: In July 1994,

the fragmented comet Shoemaker-Levy 9
that David helped discover

began its fateful, final approach to Jupiter.

LEVY: Instead of being one comet,
it was 20 comets or more

all running down through space

almost like linebackers
down a football field.

Each comet collided with Jupiter

at the speed of about
140,000 miles an hour.

NARRATOR: Telescopes around the world
saw radiant plumes thrown high into space,

leaving dark bruises
the size of the Earth.

Then, in 2009, it happened again.

Australian amateur astronomer
Anthony Wesley

spotted the gigantic impact.

ANTHONY WESLEY:
And this black spot,

that is about the size
of the Pacific Ocean.

NARRATOR: Once again,
Jupiter's dual gravitational role

as solar system traffic cop
and cosmic Hoover was on display.

LEVY: Jupiter is the solar system's
vacuum cleaner.

Without Jupiter, the Earth
would be walloped by a comet

maybe once every 50 years or so.

Life would not be possible on the Earth
if it were not for Jupiter.

We need Jupiter.

NARRATOR: For thousands of years,

Jupiter has been standing guardian
to life on Earth.

And now we think it's possible
it might have nurtured some of its own.

When Galileo took a closer look
at Europa, the picture changed.

JOHNSON: Europa is a fascinating object.

If you imagine descending
onto a world

that looks every place
like the frozen wastes

of the Arctic or the Antarctic,

you'd get a pretty good impression
of what's going on.

It's very, very bright because
the ice is very reflective

and broken up in places

where it looks like you have
basically ice rafts on the surface.

It would be like flying over
a moon-sized ice field, basically.

And landing on the surface you would
not see any large mountains,

you'd see criss-crossing ridges

that would look like
killer ski Slopes everyplace.

NARRATOR: Killer ski slopes
with pale pink stripes.

And all with the icy surface

at a very cool 260 degrees Fahrenheit
below zero.

MAN: If the ice is so cold,
is it just like just really, really hard?

PAPPALARDO: Yeah, yeah, yeah,
it acts just like rock.

So it's as hard as rock
at the surface of Europa.

NARRATOR: No doubt, the first person
to return from the ski slopes of Europa

will have some pretty tall stories to tell.

Europa specialist NASA's Bob Pappalardo would
like to be one of them.

PAPPALARDO: Oh, I'd love to get
down to the surface of Europa.

To walk around that surface,

it would probably kind of crunch
under your boot.

It's a very bizarre place

and really stretches our minds
to think about what's possible

in an ice world that's orbiting
a giant planet like Jupiter.

NARRATOR: Europa itself is stretched
by the gravitational strain

of being locked in an orbit
with lo and Ganymede

around its giant host.

PAPPALARDO: Every Europan day,
as it orbits Jupiter,

the stresses rotate around,

and if a crack forms

moving at just the right speed
across Europa's surface,

about the speed a person can walk,

it would follow a curved path

and explain the pattern
that we see on the surface.

You would be able to hear the cracking probably
of Europa's ice shell.

You couldn't hear that
if your head were in space,

but as soon as you put
your head to the ice

you'd probably hear
Europa creaking like a boat.

SPENCER: The processes that heat lo
are operating on Europa as well,

but on a less dramatic scale,

and so there's constant changes
in Jupiter's gravitational pull

that are distorting the surface, and that's
generating heat in the interior.

NARRATOR: This is a clue
to Europa's biggest secret:

its frozen icy shell floats above
a vast hidden ocean of salty water,

warmed by Jupiter's
intense tidal embrace.

The ocean of Europa is thought
to be over 60 miles deep,

deeper than any on Earth.

If so, there is more water hidden
on Europa than on our own blue planet.

And with water comes
the possibility of life.

JOHNSON: It sounds like a place
where life might exist.

It's protected from the radiation
environment underneath all the ice.

And it's sort of the same sort
of temperatures and pressures

as we have in Earth's oceans.

| have friends
in the oceanographic community

that want to get wet right now.

They're like, show me a hole

and I'll get a robotic submersible
down there.

NARRATOR: If there is life down here,
the challenge is getting to it.

Bill Stone has gone
where no man has gone before.

A pioneering cave diver
and aerospace engineer,

he now wants to go diving in an alien ocean some
500 million miles from home.

And he's developing
the technology to do it.

BILL STONE: We started off
with the idea of two things.

One is this gadget that swims

has to be intelligent enough
to understand where it is.

What we wanted to create was
a field microbiologist on silicon,

that did everything
that a good microbiologist

would go out and do in the field.

NARRATOR: His Depth X and Endurance intelligent
autonomous robots

have already proven themselves
as very capable explorers

in impossible underwater situations:

mapping deep subterranean
caverns in Mexico,

and now exploring deep below
ice-covered lakes in Antarctica.

As these robot submarines
accomplish great missions,

the possibility of one day melting our way
into Europa's deep ocean

is moving from fiction toward fact.

CHRIS McKAY: Let's just imagine
that we're on a little spacecraft

with the capability
to melt through the ice,

we push down, whoom,
plowing through the ice.

We hit the water,
that may be an interesting zone,

right there at the interface
between the water and the ice,

and we look around.

What we might see
is a community of organisms

that are growing on energy
that's coming through the ice,

oxidants, maybe even oxygen, produced
by sunlight on the surface of the ice,

being mixed through the ice
reacting with the water,

and at that interface
energy is being released,

organisms are consuming
that energy.

Okay, that's cool.

We then go deeper,
down to the bottom of the ocean,

there we see maybe
hot hydrothermal vents,

deep-sea vents
like we see on Earth,

where tidal energy, which is being
caused by Jupiter's gravitational pull,

is pumping hot fluids
through the crust.

That's what we will be hoping to find.

NARRATOR: On Earth, we have found communities of
life doing just fine,

cut off from life above

and huddling for warmth
and sustenance

around volcanic vents
in the deep sea.

This is what makes Europa
SO appealing:

there should be warm salty water

interacting directly
with a hot, rocky seafloor.

PAPPALARDO: Life is like a little battery.

It runs off a chemical reaction.

If that rocky mantle is hot,

then, like black smokers
on the ocean floors of the Earth,

there could be the chemistry
that powers life

just pouring into that ocean
from hot locations on that ocean floor.

If Europa is an environment
where we think there should be life,

then it's important
to know, is there?

Does life get going easily
given the right conditions?

Or for that matter, if there's
no life in Europa's ocean

and the conditions
are favorable to life,

why not, and how rare, then,
is life as we know it on Earth?

NARRATOR: In 2003,
with fuel and power running low,

Galileo's 14-year odyssey
was brought to an end--

deliberately, to ensure Europa
remained uncontaminated

by an out-of-control spacecraft
with a load of earthly bacteria.

ALEXANDER: | was responsible
for Galileo's bitter end, on purpose.

My friends always
remind me to say,

“Make sure you tell people
it was on purpose."

So the idea was to, you know,
come into the atmosphere of Jupiter

with enough velocity that it would
break up and be destroyed,

you know, pretty much right away.

It's now part of Jupiter.

NARRATOR: Meanwhile, back on Earth,
our return to Jupiter is being planned.

In the construction bays
at Lockheed Martin,

the Juno spacecraft is taking shape,

getting ready for its close encounter
later in the decade.

And looking ahead, NASA
and the European Space Agency

are joining forces
to send two spacecraft,

one each, to orbit
Ganymede and Europa.

This essential, detailed reconnaissance
will set the stage for the ultimate goal

of exploring an alien ocean
by robot submarine.

STONE: Europa is
a good place for robots. Why?

Number one, it's a heck
of a long ways away.

Our propulsion systems are not
ready for it, to deliver people there.

And second, the radiation environment
on the surface of that moon

is dangerous as hell.

Five minutes exposure
to an unshielded human,

and you've received
a lethal rem dose,

so you don't want to put
people on Europa,

but we can definitely put robots there,

and is there a reason to go?

You bet.

Right, it's a totally
unexplored world,

and it probably has the highest probability
of life off this planet.

NARRATOR: One day we might develop
the magnetic field technology necessary

to keep a human alive within
Jupiter's radiation environment.

But in the near future our exploration
will continue by machine.

JOHNSON: The robotic program
isn't about robots;

it's a profoundly human activity.

We're just sending pieces of ourselves
out there to do these jobs.

INGERSOLL: Pretty soon you are
using the eyes of the spacecraft

as your eyes,

and you get very attached
to your heroic spacecraft,

which survives numerous
death-defying experiences.

JOHNSON: If you listen to people

who've been involved in these
explorations over the years,

they say, oh, that was the year
we went by Enceladus,

that's the year we went to Neptune,
very much a personal thing.

The difference between being here,
being there, starts blurring.

NARRATOR: To be so familiar
with such alien worlds

shows how far we've traveled
thanks to Galileo:

both the man and the robot.

And the voyage continues.

SPENCER: I'd love to visit lo
if | could.

It's one of my favorite places
in the solar system.

You would always have Jupiter
hanging in the background;

huge and multicolored
and constantly changing.

It would be a pretty amazing
place to see.

INGERSOLL: For a trip to study
the weather of Jupiter,

| would get down in the atmosphere
where the lightning is being formed,

and I'd just look out the window
and enjoy the flashes.

PAPPALARDO: Europa kind of has it all.

I'd love to be able to poke around
down there in Europa's ocean.

Might there really be life down there?

It's probably not something
I'll know in my lifetime,

but we'll set the stage

for the next generation
of explorers to find out.

NARRATOR: However we reach
across the ocean of space,

the kingdom of Jupiter has
a lot to offer a visitor from Earth.

It's far out and far away
and tempting us to visit.