All language subtitles for A.Travelers.Guide.to.the Planets.S01E04.Mars.2010.1080p.BluRay.DD5.1.x264-c0kE_track3_[eng]

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

NARRATOR: Have you ever fantasized
about going somewhere special?

Somewhere far from crowds,
off the beaten track?

Somewhere out of this world?

Is it time to catch a rocket
to the red planet?

MAN: Mars is filled with mysteries:
volcanoes 75,000 feet tall,

huge canyons,
3,000 miles across and 6 miles deep,

all kinds of interesting features.

NARRATOR: Awaiting you
is some of the greatest scenery

in our solar system,

on a world where water once ruled,
then vanished into thin air.

Where lost microbe empires
may still survive underground.

We've seen the postcards,
and we do wish we were there.

MAN: Just the thought
of being in this new world,

seeing a landscape that
no other person had seen before,

| think there are a lot of astronauts
that would sign up to that.

NARRATOR: But don't be fooled:
nothing about going to Mars will be easy.

Danger awaits you
on this desolate beauty,

and perhaps Martians, too.

MAN: If we find on Mars evidence
of a second independent origin of life,

that's hugely profound
because it tells us right away

that life is common
in the universe.

NARRATOR: Mars.

Invaded by a robot and perhaps soon
by an Earthling like you.

MAN: Would | like to go to Mars?
Oh, in a heartbeat.

Absolutely.

If there was any way
for me to be going to Mars

| wouldn't be screwing around with robots,
you know, I'd want to go myself.

NARRATOR: There has never
been a better time

to boldly go where no human
has gone before:

to follow in the footsteps
of our robot pioneers

and visit the planets
of the solar system.

NEIL ARMSTRONG:
That's one small step for man...

MAN: Oh, man, that's incredible!

NARRATOR: It's been said
that the first person on Mars

is alive somewhere on Earth today.

Imagine it's you.

What do you need to know?

How might you get there
and what should you pack?

What are some of the must-see sights

and what should you avoid?

Think of this as your personal travel guide
to exploring the red planet.

Mars has always had a mystique.

It's one of the easier planets
to spot in the night sky,

a constant dot of red light
moving through the heavens.

And now we know for sure
that of all the planets,

this red, rocky one
is the most similar to home.

Here are polar caps
and sun-baked deserts,

giant volcanoes
and mighty canyons.

Mars even spins at about
the same speed as Earth,

making a Martian day only
about 40 minutes longer than ours.

Although it's further out from the sun
and takes twice as long to circle it,

the long Martian year
has identifiable seasons.

And what's more: our two planets
share a common childhood.

LYNN ROTHSCHILD: In many ways
it's a sister of the Earth.

It was formed at roughly the same time,
about 4.5 billion years ago

with a little change here and there.

It also was formed
of the same sorts of materials,

bombarded by comets
and asteroids.

So it has the same
delivery system we have.

NARRATOR: Could life have been forged
in the same way on both planets?

When we sent the first probes
to investigate in the 1960s,

almost anything was possible.

ROTHSCHILD: Originally
in the popular imagination

we thought that Mars might be
inhabited by whole civilizations,

building canals and so on.

And then the Mariner flyby missions

really painted a very grim black and white
view of Mars as being barren.

ANNOUNCER: The pictures and data
recorded by Mariner 4

revealed Mars to be
a cold, barren planet.

MAN: We should be coming up
on terminal descent ignition.

MAN: SCS is close to vertical.

NARRATOR: Still, NASA was eager
to look for signs of life.

In 1976, the Viking spacecraft arrives
from Earth for our first close encounter.

And there are still hopes
of a welcoming committee.

But both Viking spacecraft
send back photos

of nothing but rocks and sand.

BEN CLARK: We had cameras,
so obviously if there was a yucca plant

or | was hoping there would be
a freeway in the distance,

but what the main thrust
of Viking was actually,

was some chemical laboratories

and they looked for
the chemical signs of life.

NARRATOR: Even the dirt
seems devoid of life.

ROTHSCHILD: There was
always the chance

that when they were so busy
looking for microbes

there could be a large organism
looking over their shoulder

that they completely missed.

But now we have
enormous amount of imagery

that shows nothing
like a large organism.

There are no cats running around,

there are no bisons,
there are no palm trees.

NARRATOR: It seems Mars
is not the kind of planet

that gives up its secrets easily.

But if you dig a little deeper,

you soon find that this is a world
worthy of a closer look.

There are some basic things
you should know about Mars

before leaving home.

Most days will be
clear and sunny and cold.

The average temperature on Mars
is as bitter as mid-winter in Antarctica.

At about half the diameter of the Earth,
Mars is a handy size.

But it's much less dense than Earth,
with about a third the gravity.

Surprisingly, the actual surface area
is almost exactly the same

as all the dry land on Earth
shrunk together without the oceans.

Build a few freeways and you could drive around
Mars in a couple of weeks.

And driving around Mars is exactly
what planetary scientist Steve Squyres

has been doing since 2004.

Not in person, but via NASA's
two off-road robot rovers,

Spirit and Opportunity.

[applause]

STEVE SQUYRES: It looks like nothing
I've ever seen before in my life.

NARRATOR: For all of us
here on Earth,

the snapshots sent back
by these forward scouts

are the next best thing
to standing on Mars in a spacesuit.

SQUYRES: We very consciously gave
these robots some human-like qualities.

The cameras are about
this high off the ground;

they are the same height
as human eyes.

The visual experience that you get
from looking at the rovers’ pictures

is intentionally like
what you would get

if you were looking out the visor
of your helmet and a spacesuit on Mars.

NARRATOR: In the four decades
since our robots first arrived,

the once fuzzy ball
at the end of our telescopes

has steadily focused into
a red planet we can understand.

And it's not a welcoming place.

The problem is the atmosphere
is so thin and cold

that water exists only as solid ice
in the ground or vapor in the air,

not as a liquid on the surface.

You might see some fine, wispy clouds
high in the sky,

but don't bother bringing
an umbrella.

The whole planet is drier
than the dustiest desert on Earth.

And there hasn't been
a drop of rain here

for millions, perhaps billions,
of years.

SQUYRES: The thing
that fascinated me

was that we could see valleys
snaking across the surface

that had clearly been carved
by flowing water.

So this is telling us
that in the past it was different

and not only that,
it was different

in a way that would have made it
more suitable for life than it is today,

and that I found
truly compelling.

CLARK: We are very convinced
that at one time

it was a very hospitable planet
with liquid water

and enough atmosphere
to sustain a climate,

and so now we're trying to understand
how did it change,

why did it change
and what still might be on Mars?

NARRATOR: These are
deep Martian mysteries.

lf Mars and Earth started
as sister planets,

did life once festoon
the Martian surface?

Might it still be there?

And where did all
the atmosphere and water go?

Solving these puzzles has challenged
our planetary explorers

from the moment the first Martian postcards were
sent back to Earth.

SQUYRES: It's the fact
that it is so much like Earth

that kind of makes Mars
such a special place.

NARRATOR: Steve Squyres'
Martian odyssey

has taken him from pole to pole--

visiting those places on Earth

that share at least some
of the same characteristics:

they are extremely dry,
extremely cold,

or extremely dead:

Death Valley is
one of his favorites.

SQUYRES: This is actually
a really important place.

It's a place we call Mars Hill.

We first found this place
about 20 years ago.

In those days the only successful landings
that had taken place on Mars

were the two Viking landers,

and they landed in places
that looked very much like this.

NARRATOR: In order to plan
for the current Mars mission

and to test the cameras
and other equipment,

NASA needed a good Mars look-alike.

They found it at Mars Hill.

SQUYRES: To your eyes

the main way in which Mars
would look different from this scene

would be the color.

The color of the sky
and the color of the rocks

and the color of the soil.

The colors on Mars are painted
from a very narrow palette.

NARRATOR: The color palette here
is based on rust.

Rich in iron oxides, the rocks
and soil and the rusty dust

are always blowing around
in the freeze-dried atmosphere.

You won't see any blue skies
in the tourist brochures for Mars.

Instead, they're amber.

Not only do the dust particles
add a rosy blush to the sky,

they also scatter sunlight

in a way that turns the color
of the Martian sky

upside down to human eyes:

red by day and blue
at dawn and dusk.

This is a sunset
as seen by Spirit:

a cold blue sun dropping
over a distant alien horizon.

Looking up into the clear, starry skies
from the surface,

you would see
Mars' two tiny moons:

Phobos and the smaller Deimos.

With all the grace of a space potato
and barely 17 miles long,

Phobos has been targeted
as a potential stepping stone

for the first human mission to Mars.

A test run, before attempting the fuel-hungry and
risky trip to the planet below.

RICH ZUREK: To put humans
on the surface of Mars,

someone once joked there are
only three issues--

getting them there, keeping them alive
while they're there

and getting them back.

NARRATOR: Our Space Age dreams
of off-world colonies on the moon and Mars

faded with the cancellation
of the Apollo program

and the last trip
to the lunar surface in 1972.

It didn't stop us from traveling.

We simply switched from astronauts
to lower cost, lower risk robotic explorers.

And when it comes to Mars,
it's probably just as well.

SQUYRES: Getting to Mars
is just unbelievably hard.

You know, we've learned that
the hard way.

Before--certainly you have to go back
to the days before the rovers launched--

two thirds of the missions
that have been flown to Mars had failed.

And they failed
for all kinds of reasons--

rockets that blew up and spacecraft that
just vanished with hardly without a trace.

MAN: 5, 4, 3, 2, 1...

Engines start.

We have liftoff
from Earth to planet Mars.

NARRATOR: If you are ever
lucky enough to book a flight

on the first rocket to the red planet,

you'd better be sure
you've packed everything.

The one-way trip
is at least six months,

with no turning back
if you've forgotten something.

CLARK: We can go to the moon
and get back in a week.

It takes about three years
to go to Mars and come back.

You have to carry your food,

you have to recycle your
breathing oxygen and your water,

so it's a very, very
major undertaking.

Within about three days,
the Earth looks very small,

and within a week,
it's just another star

and you suddenly are going to realize
you're in very deep space

and it's going to be a long time
before you can go back.

NARRATOR: Before we take
this giant leap,

we need to be able to carry
everything needed

for a three-year round trip with us.

This is a much larger effort
than getting to the moon.

It's the Apollo mission on steroids.

CLARK: At this point we know

at least as much
as the engineers knew

at the time that they agreed
to land on the moon,

and they had only nine years.

So | think once the nation decides
they really want to land humans on Mars,

the system can be designed
and developed and built.

NARRATOR: Fast forward to the future.

After six months crossing
the blackness of space,

things suddenly get
a lot more interesting.

The combination
of a high approach speed,

a thin atmosphere
and twice the gravity of the moon

makes Mars one of the hardest places
to land in the solar system.

Even for robots.

SQUYRES: You hit the top
of the Martian atmosphere

and you're going Mach 27--

27 times the speed of sound--

and for our vehicles

between when we hit the top
of the Martian atmosphere

to when we were bouncing on the surface
with the air bags was 6 minutes.

It's a hell of a ride.

You use a heat shield
to slow you down

to a leisurely Mach 2,
twice the speed of sound.

And then we throw out
a supersonic parachute.

NARRATOR: Everything is complex,

and everything has to happen
precisely on time.

SQUYRES: The worst part
is when you come into contact

with the Martian surface.

There's no runway, okay.

There's no nice place to land,

and you can't control very well
where you're going to come down.

So you're going to come down
in a field of rocks like this.

How do you guarantee

that your billion-dollar spacecraft
is actually going to survive that?

The approach that worked for us
with our rovers was great big air bags.

Bounce, bounce, bounce,
bounce, bounce,

finally the vehicles comes to rest.

The Vikings used rocket motors,

and they just touched down
gently on the surface

and they were fortunate.

It was just good luck.

They landed in a field
of boulders like this

but they didn't land with one
that was poking through the belly,

and it all worked.

You have to be good,
and you have to be lucky.

NARRATOR: Want to step outside
to take in the scenery

or pick up some rocks?

As familiar as it might look
beyond the porthole,

Mars is dangerously alien.

The upside is that the low gravity
will give you super jumping abilities.

The down, the almost complete lack
of an atmosphere.

This is not home:
there is nothing here to breathe.

To find similar conditions

of low temperature
and pressure on Earth,

you have to travel three times
higher than a commercial airplane,

to the very edge of space.

Planetary scientist Bob Brown

shows why you should keep
your helmet on when visiting Mars.

BROWN: We have this,
just a beaker full of water.

We're going to put it
in this little chamber.

And attach a vacuum hose
to the chamber.

And haul the air
out of the chamber.

NARRATOR: As the pressure drops
to Martian levels,

the water boils at room temperature.

BROWN: So If you were
to take your helmet off on Mars,

the liquid in your face, especially,
would start to boil

much the same as this liquid water
started to boil.

And | guess | don't have to describe
what that might feel like

or what it might look like.

NARRATOR: A medical travel advisory
might say to keep your suit tightly fitted,

but so far no one's built a suit
that'll work on Mars.

Existing spacesuits
are simply too bulky, too heavy

and too complicated to wear

for the sort of regular activity required
on the unforgiving surface of Mars.

CHRIS McKAY: Something we
take for granted here.

We get up in the morning,

| put on a shirt and a pair of jeans
and out I go.

So it's got to be routine,
easy to use.

Many times | have been
working out in the field

in the Antarctic or the Arctic

and | just have to take the gloves off,

because I'm doing something

that requires that quintessential
human capability

of touch and feel and hold.

So my request to the engineers
is give me a spacesuit with gloves

that will keep me warm
and keep me pressurized

but still allow me
to use my hands.

NARRATOR: Not only will you
want to move your fingers,

you'll want to move around.

NASA's lunar electric rover

is a prototype for future missions
to the moon and Mars.

It's part vehicle
and part spacesuit.

MIKE GERNHARDT: | can just picture
being there in a vehicle of this type

and looking back at Earth
in the distance

and deciding to go EVA

and be in boots on the surface
in 10 minutes,

which would just be
a remarkable breakthrough.

NARRATOR: Astronauts
can cover more ground

by living in the vehicle
for weeks at time,

stepping outside
when they want to

and back inside
at the first sign of danger.

SQUYRES: Mars does not have
a powerful magnetic field

the way Earth does,

so there's radiation
from the sun,

also cosmic rays that are going
to penetrate through spacesuits.

NARRATOR: An astronaut might get
a 30-minute warning

of an incoming solar storm,

but less predictable is the risk
of being hit by a meteorite.

Recent estimates based
on fresh crater counts

suggest that up to 200 new holes

are blasted into the surface
of Mars each year.

And even the Martian moons are not
guaranteed to stay in place.

The days of Phobos
are numbered.

Possibly an asteroid
that once strayed too close,

the moon is trapped
in a fatal gravitational embrace.

Every passing century
sees it drop six feet closer to death.

In about 50 million years,
its fall is expected to be complete.

The aftermath,
if anyone is around to see it,

could be Mars with a bright ring
of moon dust to rival Saturn's.

But events like this
are not your real danger.

It's the day-to-day exposure
to the cold, dry Martian environment

that will make a long stay tricky.

SQUYRES: It was 119 degrees Fahrenheit
here yesterday.

A really, really, really hot day on Mars,

it would get up to about
30 degrees Fahrenheit,

and at night it goes
to more than 100 below.

NARRATOR: Martian deserts
are both frozen and sun-baked:

with no ozone layer,
UV levels are so high

that any unprotected organism,
even a Martian microbe,

will be burnt to a crisp
within minutes.

A good hat is just not
going to cut it.

So why not leave all the dirty work
of exploring Mars to robots?

SQUYRES: One thing about humans

is that they have a capability
to improvise on the spot,

even if you don't have
the right tools with you,

that robots lack.

In Death Valley this stuff was wet,
it got dry;

when it dried, it cracked.

We're investigating the idea that
something similar happened on Mars.

You know, I'd love to be able
to do this on Mars, and we can't,

but a human on the scene
can improvise pretty well.

NARRATOR: Getting down and dirty
on Mars will mean exactly that.

When an ill wind blows on the red planet,
dust really does go everywhere.

About once every three years,
local storms go global

and the dust can block
your view for months.

It happened the very first time
we sent a probe into orbit in 1971.

ZUREK: When Mariner 9
got to the planet

there was a giant dust storm

that had completely shrouded
the surface from it.

SMITH: They could see
nothing, nothing, just dust.

And as the dust
started to recede

all of a sudden
these dots appeared.

There were three of them lined up.

What the heck are those?

It turned out to be the peaks
of the three great volcanoes on Mars.

ZUREK: And that's when
we began to realize

just how varied the terrain
and topography of Mars was.

NARRATOR: This was the moment
that Mars began to reveal itself:

a world with a secret history
and the spectacular scenery to match.

Thanks to our sharp-eyed spacecraft,
Mars is opening up like never before.

These are real landscapes that humans
will one day marvel at in person.

SQUYRES: If you were going to Mars,
you'd want to go for the scenery, right?

| mean, you're not going
for the culture,

you're not going for the climate,

so you definitely want to go
for the scenery.

One thing that people forget
is that when we've landed on Mars

we have to go to places
that are safe,

and safe equals
pretty smooth and flat.

NARRATOR: Here's a bit of Mars
that's anything but smooth and flat:

the magnificent Valles Marineris.

This titanic canyon system,

over 2,500 miles long
and 6 miles deep,

is probably the grandest geological feature
in the solar system.

It's clearly the red planet's
must-see destination.

DAVID SOUTHWOOD:
As a human being

it's the sheer gigantism of Mars
that is amazing.

The Valles Marineris
beats the Grand Canyon hollow,

and if you've ever seen the Grand Canyon,
you will never forget it.

NARRATOR: It's so colossal,

the Grand Canyon would be easily swallowed
by one of the smaller side branches.

ZUREK: We're talking
about something here

that's the width of the United States
or of Australia across here.

SQUYRES: | think the Valles Marineris
would be the place to go.

Build a lodge right on the rim
so you can look in.

NARRATOR: The attraction goes
beyond sheer scenic splendor:

deeper than the canyon itself
is the mystery surrounding its formation.

This giant fissure,
once filled by mighty lakes,

has been scoured by floods
of biblical proportions.

SQUYRES: You can make estimates

of how much water
had to have been flowing

to carve these things,

and you get numbers like 100, 200
Amazon Rivers all cut loose at once.

Big, big amounts of water
flowing across the surface.

NARRATOR: The other big attraction
on Mars

is the largest volcano,
and highest mountain,

in the solar system.

Olympus Mons towers
at an astounding 17 miles,

three times higher than Everest.

Its base covers more ground
than the United Kingdom,

and the massive caldera
at its summit

could easily swallow greater London,
Paris and New York.

SQUYRES: So things
tend to be big on Mars.

| think in part that's because
the planet has lower gravity,

so when you pile up lava,
you can pile it three times higher

because the gravity
is three times less

before it will start to collapse
under its own weight.

NARRATOR: Mars is a far more active world than
previously thought.

We see landslides of dust

and gullies freshly carved by outflows
of mysterious fluid.

And this peculiar region
has been claimed

as a flash-frozen sea,
complete with fossil icebergs.

Likewise there are glaciers,
geologically recent

but now buried beneath
a protective blanket of dust,

waiting for the next change
in climate.

Still, most of the defining
surface features of Mars

were carved way back
in the good old days.

SMITH: Certainly something happened
in the early history of Mars

that led to great releases
of water,

and of course people wonder
with that much water

could there have been
ancient oceans,

could there have
been environments

that were very much
like life environments

on the early Earth?

NARRATOR: Early Mars
was a different world.

A world with a thicker atmosphere;
with weather and water.

Possibly a vast, shallow
northern ocean.

This was really the time
to go to Mars:

when you didn't need a spacesuit,

perhaps just an oxygen tank
and some warm clothes.

McKAY: When we reconstruct
in our imaginations

Mars of three billion years ago,

we tend to make it like Earth,
warm and cozy.

But it wasn't.

Mars, back in its wettest,
warmest phase,

was probably like Earth today
in its coldest regions.

So I'm imagining a place

where the snow and ice
is melting in the summer

to form transient ponds and streams
and ice-covered lakes.

It's cold, it's wet,
but it could be rich with life.

NARRATOR: This is the Mars

that we want our astronauts
to get their hands on,

to bring back and study--

the wet Mars of old,

where we might find
the evidence of life.

If you want to find life on Mars,
first you need to find water.

And not all of the planet's water story
is ancient history.

There's been plenty
of frozen underground evidence

detected from orbit,

but scientists needed
to touch and taste it to be sure.

In 2008, they finally got their opportunity
when NASA's Phoenix lander

made a daring approach
to the high Martian Arctic.

MAN: 50 meters.
Land init sequence initiated.

[applause]

SMITH: There was not ever
more excitement in my life

than landing safely on Mars.

I've been through the opposite.

I've been through a landing
that was not successful,

and | did not want that
to happen again.

NARRATOR: The landing
was not only perfect,

but the engines exposed
suspicious white patches

directly underneath the spacecraft.

Water ice was just
a few scrapes away.

SMITH: We did find water ice

and we found that the soil
in connection to it

has calcium carbonate,

a compound that forms
in the presence of liquid water.

If it had been wet,

then we wanted to look
for nutrients and food sources

that could support microbes.

NARRATOR: The water ice is proof
of a valuable resource

for any life forms still clinging
beneath the surface,

and for future travelers.

SMITH: We now know that these plains
that you see stretching behind me

are underlain only 2 or 3 inches deep
by a sheet of ice,

all the way as far as you can see.

Great hockey rink.

If you had a hockey team on Mars,
all you'd need is a broom.

NARRATOR: The possibility
of running into Martians

received another boost

from a very Mars-like part
of our own planet,

Chile's extraordinary Atacama Desert.

McKAY: The Atacama is special
because it is just so profoundly dry.

Speaking roughly, it's 50 times drier
than Death Valley.

It is deader than Death Valley.

It's the only place on Earth
where Viking could have landed

and searched for life in dirt on Earth
and not found it,

and instead found a reactive mixture
of chemicals, the only place.

NARRATOR: Even here, in the driest corner
of the driest desert on Earth,

life has confounded scientists.

Cyanobacteria have been found

living inside the rock-hard salt
of a long gone lake.

BENITO GOMEZ: This is a halite,
it's a sodium chloride salt,

which is colonized
by cyanobacteria.

It's dark green because they have
this particular pigment

protecting them from the excess
of UV light.

NARRATOR: Once in a blue moon,
a fleeting early morning ground fog

delivers some rare humidity
to the air above the desert.

This precious moisture is greedily
sucked into the microscopic pores

of the water-hungry rock salt.

GOMEZ: This is a very rare event.

So these bacteria are living
in an environment

where liquid water is available
a few hours during one year.

Very, very hard.

NARRATOR: If we're looking
for Martian bugs,

we should search for life forms
at least as tough and alien as this.

ROTHSCHILD: I'm looking at Mars
from the point of view of a microbe,

and as a microbe | really need
a very, very tiny amount of water.

| could probably live
my entire life happily

in a tiny drop of water
about the size of the point of a pen.

Now we've shown over the years

that organisms that live
in salt crusts on the Earth

have enough sunlight coming in

so that they can go through
their day-to-day activities

but still be protected
from the radiation,

and we know there
are salt crusts on Mars.

NARRATOR: Mars has a long-term wobble
to its orbit

and every 5 million years or so,

the poles end up tilting
45 degrees toward the sun.

McKAY: A way of thinking
about the Phoenix landing site

is think about
the polar regions on Earth.

Imagine you're there in winter.

It's very inhospitable,
very cold, very alien.

You think, how can anything
survive here?

Come back six months later
and it's like a different world.

The sun is shining,
it's wet, it's warm,

things are alive
and scurrying around.

So we may be being misled
seeing this frozen, cold site,

and in fact, we're just there
at the wrong season.

NARRATOR: We know that on Earth
some bacteria can survive being frozen

for millions of years.

They can also eat perchlorate,

the highly reactive chemical
Phoenix found in the Martian soil.

McKAY: Presumably, if there was life
at the Phoenix site

it had learned the same trick.

And so there might be organisms
that are literally eating the rocks

and reacting with perchlorate
below the surface

shielded from the ultraviolet light

just having a great old time
five million years ago.

The party is over
because everybody froze,

but in another five million years
the party will start up again

as the Martian summer comes
to the north polar regions

and the ice turns to water.

NARRATOR: The party might not
be over everywhere.

The gas methane has been found
both by spacecraft in orbit

and by telescopes from Earth.

It's chemically impossible
for methane to survive for long

in the Martian atmosphere,

so it must have been
released recently.

SQUYRES: Now what makes methane?

Cows make methane;
it's probably not cows.

Microbes of various sorts
can release methane.

There are a variety
of geologic processes.

Volcanoes can release methane.

So the mere fact that there's methane
doesn't say life,

but either way the methane says
that Mars is an active planet.

It's either biologically active
or it's geologically active or both.

NARRATOR: The methane release
appears to be seasonal

and linked to areas
of suspected sub-surface ice.

Ice found exposed
in fresh craters

has proven that water lurks
not only near the poles

but also much closer
to the equator.

It's pretty clear that if the Viking landers
had dug just 4 inches deeper,

they would have reached this ice

and perhaps a totally different conclusion
about life on the red planet.

ROTHSCHILD: So if Mars
has any life at all,

whether it is so small
you can only see it with a microscope

or if they had a mammoth,
it wouldn't matter to me;

it's the whole question
of is there life at all on Mars.

NARRATOR: Either way, there certainly
will be life on Mars

the moment the first
human traveler arrives.

In 2009, six men walked
into a series of connected rooms

inside a warehouse
in the Moscow suburbs

and shut the door behind them,
for three months.

They took all their food with them
and drank recycled water.

The only communication
with the outside world

was electronic,
with a 20-minute delay.

They were trying to simulate
a flight to Mars.

There is no room to screw up
on a trip like this,

mental or otherwise.

Once on Mars you are likely
to be stuck there for a year or more

waiting for a window of opportunity
to ride home.

And, unlike a robot,

the hopes and fears of the whole planet
will be riding with you.

SQUYRES: | think that humans
are going to do a better job

of exploring Mars ultimately
than robots ever can.

Robots move really slowly.

Okay, what Spirit and Opportunity
have done in 5 years on Mars

two astronauts could probably
have done in a week.

NARRATOR: As fast and as smart
as we are,

we still need mechanical help
to scout the course for Mars.

The next robot rolling onto red dirt
will be aptly named Curiosity.

SQUYRES: It's the size of a small car,
and it has a nuclear power source,

so you don't have to worry
about dust accumulating on solar arrays

or anything like that.

And most importantly
it has the capability

to look for trace quantities
of organic molecules,

SO we've gone beyond now
looking for evidence of habitability

to actually looking for evidence
of the building blocks of life.

NARRATOR: Whether it's alive or dead,
a trip to this red planet

has a lot to teach us
about our lonely blue one

and the universe beyond.

ROTHSCHILD: Now, if you
have two planets

that are next to each other
in the same solar system

that both had independent
origins of life,

you would have to conclude

that the chance of having life
all over the universe,

indeed even in other places
in our solar system,

would be very high.

| think you could basically
go to the bank and bet on it.

McKAY: We're not going to Mars
just to search for life,

we're going to Mars to search
for a second genesis of life.

We'd like to find something
that's different from us,

that doesn't have
the same genetic history

and genetic code that we have.

And, from my point of view,
the more alien the better.

ROTHSCHILD: Now, the second possibility
is that we find life on Mars,

but my goodness, it has
a genetic code exactly like us,

it uses DNA.

It's too coincidental.

This is representing our cousins.

Life either arose on Earth
and went to Mars,

or actually more likely that life
originated on Mars

and it was transported
on a meteorite or a comet

to the Earth early on

and in fact our home planet is Mars.

NARRATOR: So, in some ways
a voyage to Mars

could be a voyage home.

Our ancestors have made
such bold trips before.

When we walked out of Africa.

When we sailed over the horizon.

If it's technically possible,
our ships will head out again.

ZUREK: We've always wanted to see
what's over the next hill,

and Mars is that next "over the hill."

Sure, you're going to have be in a suit,
you're going to have to have a habitat,

but it's a solid planet,
it's got a surface,

you can see, you can work,
you can explore.

CLARK: I've thought
for about 30 years now

that we could go to Mars,

and usually when people ask me
how long it would take,

I say 15 years

because we've been saying 15 years
for the last about four decades.

SQUYRES: A human mission to Mars
can't happen soon enough for me.

You know, I'm a robot guy.

That's what | do with my career

is build robots
and send them to Mars,

but | also think that we send things to Mars
for reasons other than science.

Our rovers Spirit and Opportunity

were built by people who, like me,
grew up in the ‘60s

watching Mercury, Gemini, Apollo
on TV as little kids

and dreaming of sending
spaceships to Mars someday,

and now we do,

and | think as people watch

the first human explorers
on the surface of Mars,

they are going to be
similarly inspired

to do things that | can't even
imagine at this point.

It's going to be very costly,
it's going to be dangerous,

but | think it's something
I'd certainly like to see happen.

I'd love to see boot prints
in our wheel tracks.

| would love to see
boot prints on Mars.

NARRATOR: When the first human footprint
is made on Mars,

it will represent more
than a giant stride into space.

This one small impression
will be proof

that humanity is once again
on the move;

travelers once more moving
beyond our comfort zone

to explore new lands
and new opportunities.

And have no doubt, there are many worlds
out there, ripe for exploration.