Nova (1974–…): Season 36, Episode 8 - Is There Life on Mars? - full transcript

NARRATOR:
Is there life beyond Earth?

To find out, we might
look no farther

than the planet next door.

Mars may be our best hope for
resolving the ultimate mystery

of creation.

MAN:
It is the one planet

out there that is
Earth-like enough

that we can imagine that life
might have taken hold

on that world.

MAN:
If we go to Mars,
will we find that, yes,

the same events that led
to life on Earth



happened independently
on this other planet?

MAN:
And if we find evidence on
our very next planet, Mars,

then you have to say

that has to be so common across
the Milky Way,

across the universe, you know
that we are not alone.

NARRATOR:
Mars has more in common
with our world

than any place we know of
in the universe.

But it's still a world away.

Getting an astronaut there to
search for life is beyond us.

So for now we must resort
to the next best thing...

(electronic whirring)

Robots.

Mars today is a busy place.

Three satellites orbit it.



Three landers ponder
its surface.

They're finding
a wealth of clues.

MAN:
Holy smokes!
I'm just blown away by this.

MAN:
When that first data comes down,

the sense of astonishment
is indescribable.

Oh, wow!

MAN:
We would never have thought

of looking for organisms
like this on Mars.

NARRATOR:
But they're also discovering
that, in its past,

Mars had some dark secrets.

Life can survive
in pretty harsh conditions,

but there are limits.

MAN:
Around four billion years ago,

there was a cataclysmic event.

MAN:
And this was big.

This thing went wham--
right into the planet.

NARRATOR:
Four and a half billion years
ago, two young planets emerged,

both brimming with promise.

But something went very wrong
with Earth's twin.

Is there life on Mars?

Up next on NOVA.

MajoNARRATOR: for NOVA
Mars eludes us.

Even as this planet surrenders
its secrets,

it remains stubbornly guarded
about one...

The question we have come in
pursuit of, above all others.

STEVE SQUYRES:
The geology is fascinating,

the climate is interesting,
atmospheric science.

There is any number of things
that you can study

about the planet, but to me
what makes Mars special

is its potential
as an abode for life.

NARRATOR:
If there's life on Mars,

there could be life
throughout the universe.

CHRIS McKAY:
If it happened twice,

right here in our own solar
system, then we would have,

for the first time, a good
answer to the question,

Is the universe full of life?

The answer would be yes.

PETER SMITH:
The Holy Grail
of Mars exploration

is finding some form
of Martian biology,

what's often called
the Second Genesis.

Did life start on Earth
and Mars?

Did it evolve in a totally
different way

than Earth-life did?

NARRATOR:
Peter Smith has been involved
with seven missions to Mars.

Each has only driven home how
difficult it is to get there.

MAN:
This is the Mars Polar Lander
Mission Control

at the Jet Propulsion Center.

NARRATOR:
1999.

The Mars Polar Lander is about
to touch down on the surface.

Smith and his team should get
word any moment.

They wait...

There's nothing worse
than no signal.

NARRATOR:
...and wait, for a signal
that never comes.

SMITH:
I was trying

to hold out a little hope
that maybe it landed

and the communication link
hadn't quite set up yet,

but I had the worst
sinking feeling.

MAN:
The mood doesn't look
too good over there.

NARRATOR:
During its descent,
the Polar Lander disappeared.

SMITH:
You felt like

somebody very close to you
in your life,

someone you love very dearly,
had died

through some tragic accident.

NARRATOR:
At the time, Smith was already
preparing his next mission,

another lander called
Mars Surveyor.

But after the failure
of Polar Lander,

NASA canceled the mission.

SMITH:
Oh, it was just miserable.

All fell apart.

All my house of cards
just collapsed.

NARRATOR:
Smith didn't give up.

His plan: To take the technology
from those failed missions

out of mothballs, and repurpose
it for another lander.

Every precaution would be taken
to make sure

this one would make it.

He christens the new mission
with a name apropos: Phoenix.

SMITH:
We are rising from the ashes,

and we're going back to Mars.

MISSION CONTROL:
Zero and liftoff.

SMITH:
And so, Phoenix it is.

Sending a mission to Mars

is somewhat like hitting a golf
ball across the solar system.

We'll see if we got
our hole in one.

NARRATOR:
Nine months later.

Smith is back on track to search
for signs of life on Mars.

MAN:
Three, two, one, mark...

NARRATOR:
Mission Control at NASA's
Jet Propulsion Laboratory.

If Phoenix lands,

it'll be thanks to the engineers
here today who made it happen.

But no one knows better than
Smith what could go wrong.

Standing by for touchdown.

Touchdown signal detected.

(cheering)

NARRATOR:
Finally, Peter Smith
has arrived on Mars.

SMITH:
By gosh, we are going
and doing it.

We have a great chance of making
a new discovery on Mars.

It's the thrill of my life.

NARRATOR:
Now that Phoenix has landed,

NASA is sharing supervision
of the mission with scientists

at the University of Arizona,
where Smith is based.

Phoenix is in the far north
of Mars,

so it has just three months
before the polar sun will begin

to set for the long winter,

and with it will go
the lander's power supply.

Time is already running out.

This is the 39th time we've
tried to reach Mars

and only the seventh time
we've actually landed there.

It is a quest
years in the making.

The first to attempt it
were the Soviets.

During the 1960s, they launched
eight missions.

They failed eight times.

It wasn't until the late '70s

that we'd get our first close
view of the Martian surface,

with the two Viking Landers.

Each bears a $60 million box,

packed with three biology
experiments

that are, in their day,
state of the art.

They're designed
to test the soil

for the presence of organisms.

A member of the science team
is Carl Sagan.

SAGAN:
There may be warm, wet kinds
of organisms in a dormant state.

It may be that by dropping them
in liquid water,

Viking might have
a very pleasant surprise

in detecting such organisms.

MAN:
Now the screen for touchdown.

Touchdown!
We have touchdown.

NARRATOR:
Hopes are running high.

Many people are ready to exclude

the possibility of large
organisms on Mars,

but I see no reason to do that.

And I think it's possible that,
for example,

the Viking Lander camera
may pick up

organisms that happen to be
walking by the Viking Lander.

A silicon-based giraffe
will be detectable

if it walks
by the Viking Lander camera.

NARRATOR:
But when the pictures come in,

there are no signs of giraffes.

As the experiments proceed,
the news gets bleaker.

SMITH:
That this was devoid of life,

that Mars was just
a barren desert,

that it may have been
interesting

four billion years ago,

but today it's lacking
in those ingredients

that would allow life
to flourish.

NARRATOR:
Those ingredients for life
are common on Earth.

Billions of years ago,

life as we know it needed
three things to begin.

One is an energy source,
like heat--

from the volcanic fury

of the Earth below
and the sun's rays from above.

Two are organics--
carbon-based molecules;

not living things, but the
building blocks of life.

But the third is scarce
in our solar system:

the medium that helps
the chemicals intermingle.

The most important requirement
for life is liquid water,

and that's the defining
requirement for life

in terms of our solar system.

There's plenty of energy,
there's plenty of carbon,

there's plenty of other elements

on all the planets
in our solar system.

What's rare is liquid water.

NARRATOR:
Not only did Viking find no
life, but no water, either.

Mars was pronounced a wasteland.

DAN McCLEESE:
It was really a bummer.

Mars was "dead," unquote.

That was kind of the outcome
in the newspapers.

And so we had a hiatus of
missions to Mars of 20 years.

NARRATOR:
Mars slipped away
from the limelight.

Then, in 1996, NASA scientists
unveil a Martian rock,

a meteorite that had
landed in Antarctica,

which appears to hold
the fossilized traces

of microscopic life.

Or so they think.

It turns out the formations they
found could have been produced

by volcanic activity.

"Follow the microbe"
has not gotten NASA far.

Instead, another strategy
replaces it.

ANDY KNOLL:
Certainly, life as we understand
it requires water.

So NASA's explorational mantra
has been "follow the water."

And that's a pretty reasonable
first step.

NARRATOR:
2004-- NASA is putting wheels
on the ground...

(cheering)

...times two.

The Mars rovers Spirit and
Opportunity have landed

and are ready to roam
the planet.

The hunt for signs of water--
present or past-- is on.

Opportunity is at a spot called
Meridiani Planum...

Oh, look at this one.

Look at this!

NARRATOR:
And right away,

the first pictures it sends home
are stunning.

(team cheering)

Previous missions had sent
photos of sheer desolation.

Look at that!

NARRATOR:
But now, not far from the lander
is bedrock,

the first ever seen on Mars.

STEVE SQUYRES:
Holy smokes!

(laughter)

I'm sorry, I'm just... I'm just
blown away by this.

NAAT Bedrock is a recod
of ancient environments...

and a dream come true for
mission leader Steve Squyres.

SQUYRES:
This is the sweetest spot
I've ever seen.

(laughter)

That outcrop in the distance is
just out of this world.

I can't wait to get there.

(laughter)

SQUYRES:
Most of the rock on Mars is
volcanic lava flow.

This is something else.

This is an unusual Martian rock,

at least compared to what we've
seen everywhere else.

The fact that these rocks
are layered

says that one possible origin
for these

is that they were laid down
in liquid water.

We do not know what's going on
here, but the beauty of it is

we have preserved in front of us
a record that will answer that

and we have on our rover

a toolkit of gizmos that will
tell us that answer.

NARRATOR:
One gizmo is a camera on the end
of the robotic arm.

It finds a puzzle never before
seen on Mars:

tiny, smooth spheres,
like so many blueberries.

Could they be the product
of water?

The pellets probably formed
in the cavities of wet soil,

perhaps in a salty ocean floor.

You should circle
that one.

NARRATOR:
If the team can find certain
salts in the rock,

it will clinch the ancient
presence of water.

The place to find
those chemical clues

isn't on the surface.

They would have seeped
underground...

if only the team
could look there.

They can.

The rovers come equipped
with a drill--

the Rock Abrasion Tool,
or RAT--

as shown in this NASA animation.

But the man in charge of the RAT
is worried.

STEVE GOREVAN:
I thought that before landing

we had roughly been able

to approximate anything that
Mars was going to throw at us.

Of course, what I neglected
to think about was a rock

that would be spitting out
blueberries.

What we're afraid of happening
is that we're going to dislodge

one of the spherules

and that it's going to be
like a pinball machine

between the RAT
and the surface of the rock.

And this could be something
that causes us some problems.

NARRATOR:
The pressure is on to pick
a rock to test.

GOREVAN:
That spot for RATting
has to be chosen now.

And I mean literally

in the next, uh, well, it should
be chosen in the next...

it should be chosen
in the next hour.

WOMAN:
What is this rock?

GOREVAN:
That's McKittrick.

NARRATOR:
They've selected a spot
that's blueberry-free.

Hopefully.

This, this, I can't stand this.

It's like... I wish it was over.

MAN:
That's good, contact switch is
tripped.

MAN:
Are you ready to give
a formal "Go"

for the RAT sequence, Master?

Yes, I think we are.

MISSION MANAGER:
More definitive.

MAN:
We're go to RAT.

Go to RAT.
I like that. Okay.

You are clear to command.

GOREVAN:
On my mark: 3, 2, 1, mark.

MAN:
The RAT has been engaged.

GOREVAN:
I don't care if we find chili
under there.

(laughing):
I don't care.

I just want to make
that thing work.

NARRATOR:
The result?

Yes! You see that hole?

NARRATOR:
Direct from Mars,
a cleanly RATted hole.

SQUYRES:
It's the most important hole
we've ever dug.

NARRATOR:
Finally, they can check
the rock's chemistry.

A spectrometer onboard is able
to read each chemical

as a different wavelength,

breaking them down
like a prism does light.

The rock is as much
as 40% sulfate salt,

a mineral that's only produced
by soil interacting with water.

That clinches it--
water was once here.

SQUYRES:
That's beautiful, man.

It's so different from
anything we've seen before.

That's great!

Whew!

SQUYRES:
There's an awful lot of sulfate
salt in this rock,

and that's very, very hard
to explain away

other than water having been
massively involved

in creating this stuff.

If you tasted this thing,
you'd taste the salt.

It's a very, very
salt-rich rock.

It looks like what geologists
call an evaporite deposit.

Evaporites form when you have
liquid water

with lots of stuff
dissolved in it

and the water evaporates away
and it leaves stuff behind.

NARRATOR:
That stuff includes
the blueberries.

They hardened long ago

when these rocks were
saturated with water,

and they remained

after the softer, surrounding
rock eroded away.

SQUYRES:
So we think we're parked

on what was once the shore
of a salty sea on Mars.

That's pretty cool.

NARRATOR:
The rovers have proven,

even if they're finding no water
on Mars now,

it once flowed here,

probably over three and a half
billion years ago.

But that doesn't
necessarily mean

there were living things here.

It would have taken more
to generate life.

Amid its shallow seas,
could Mars have produced

that energy it takes to stir up
a primordial soup?

In search of clues, Spirit sets
off on a journey

of 1.4 miles and two months

to explore the rugged
Columbia Hills.

But the trek takes
such a toll on the rover,

it might not make it
to its destination.

SQUYRES:
This is one beat-up vehicle.

This thing has traveled
for three kilometers;

it's coated with dust.

We've got a gimpy wheel.

That front right wheel
is hurting.

NARRATOR:
Spirit is down to five wheels,

and there's no one to change
a tire on Mars.

Its rovings may be over.

The team troubleshoots with
their duplicate model at JPL.

WOMAN:
If we're going backwards,
and it's not a lead wheel...

It takes some, but it still
has the pressure.

Any time you drive that wheel...

SQUYRES:
We've got this dead weight

hanging off the front
of the rover

in contact with the ground.

And so when we drive now,

we have to drive that vehicle
differently.

We have to drive it backwards.

We always drive backwards,

dragging the dead wheel
as we go.

And we drag the wheel,
we go very slowly.

It's kind of painful to watch.

NARRATOR:
But the setback turns up
a surprise.

It, against all expectations,

led to the most important
discovery Spirit has made.

As we drag that dead wheel
through the soil,

it digs this wonderful
hundreds-of-meters-long trench

in the dirt.

And we looked at the soil
in the trench

and it was as white
as bright snow.

NARRATOR:
The white patches revealed
by the gimpy wheel

is another telltale mineral--

silica, the stuff of sand
and glass.

This soil is 90% silica.

It would have taken
a lot of heat

to generate that concentration.

Perhaps hot springs
like the ones on Earth

existed on Mars over three
and a half billion years ago.

SQUYRES:
This is a place where
there was hot water

and maybe steam and it would
come out of the ground.

And that provides, at least
locally, an environmental niche

that would be suitable for life.

RRATOR:
On our planet,

in these crucibles of
hydrothermal activity,

the most ancient bacteria
may have first emerged.

Liquid water...

energy.

When Mars and Earth were young,

they might have both had what
it takes to create organisms.

Roughly three and a half billion
years ago,

life may have had everything
going for it on Mars.

McKAY:
There's a real distinct parallel

between early Mars
and early Earth.

There's a real parallel there
that strengthens the case

for there being life on...
having been life on Mars.

NARRATOR:
But Andy Knoll is skeptical.

KNOLL:
Let's think about the
requirements of life.

Almost all of life on Earth

exists within
a fairly narrow band

of environmental conditions.

NARRATOR:
Not all water sustains life.

KNOLL:
It's not enough just to say
water was there.

The real question is
the properties of water.

NARRATOR:
The way the rovers found water
was by detecting salt.

So how salty were those seas?

KNOLL:
It turns out that
Meridiani Planum

was way saltier than anything
that's known to sustain life.

NARRATOR:
If water is too salty or acidic,
it can be deadly.

Three and a half billion
years ago,

the waters of Meridiani, where
Opportunity is, could have been

up to a thousand times saltier
than Earth's oceans.

SQUYRES:
It was pretty nasty stuff.

This was not nice pure water by
any stretch of the imagination.

It was very acidic--
it was acid, sulfuric acid--

and it was very salty,
it was a brine.

So, it would have been a very
challenging place for life.

NARRATOR:
What made the waters of Mars
turn to poison?

A crucial clue is revealed

when Opportunity ventures
to its next destination.

The walls of Victoria Crater
offer the chance to study

the geological record.

The deeper, the older.

SQUYRES:
Young rocks at the top,
older rocks at the bottom.

You're doing a trip
through time on Mars,

and the deeper you go,
the further back you're going.

And we use those craters

to provide us with access to
other rocks below the surface.

NARRATOR:
The base of these cliffs
could have formed

thousands of years before
the rocks at the top.

Was Mars wet then?

Sure enough, Victoria's walls
are lined with distinct bands.

Like the Grand Canyon, they are
classic sedimentary layers,

the product of era after era
of water.

Opportunity discovers that,
moving forward in time,

the salt concentration
steadily increases.

That means the amount of water
bearing that salt was dwindling.

KNOLL:
At Victoria,

we have evidence
for some water early,

less water later,
still less water since then.

It was evaporating
and the result was

it got saltier and saltier
and saltier and saltier.

NARRATOR:
It appears Mars evaporated
to death.

But why?

What could wring an entire
planet dry?

Earth is able to stay wet and
warm because its water is held

in the protection of
a blanketing atmosphere.

The Martian atmosphere is today

less than one percent
as dense as ours,

though it must have once
been robust,

since water did flow here.

What happened to it?

Chances are the sun destroyed
Mars' atmosphere

by relentlessly bombarding it
with solar wind.

Earth's atmosphere is protected
from the sun

by a powerful magnetic field.

That's generated by a spinning
molten core, creating a dynamo.

McCLEESE:
We're lucky on Earth; we
wouldn't be here otherwise.

The magnetic field actually
shields the atmosphere and us.

What it does is it manages
to keep that solar wind

from blowing
the atmosphere away.

NARRATOR:
But then Mars is a tenth
the mass of Earth.

It doesn't seem large enough

to generate a strong
magnetic field.

In fact, does Mars even have
a molten core to begin with?

Answers are emerging from a new
age of Martian exploration.

Satellites dispatched by NASA
and the European Space Agency

have been circling Mars.

The orbiters, for me,

are kind of
the unsung heroes of Mars.

The global perspective is the
thing that really gives you

the understanding of how
the planet works.

NARRATOR:
With data collected
from the satellite Mars Odyssey,

scientists were able to model

the longest canyon
in the solar system.

It stretches the length
of the continental U.S.

and could fit the Los Angeles
city basin

within the width of its walls.

With satellites,
they are reconstructing

the volcanic history of Mars,
the planet that produced

the solar system's
largest volcano.

Olympus Mons spans an area
the size of Arizona

and rises to three times
the height of Everest.

Volcanoes are no longer active
on Mars,

but their presence means

that at one time the planet did
have a molten core.

Still, how could such a small
planet pump up enough juice

to power a magnetic field?

Some scientists believe
that Mars got a little help

from a visitor from space...

a giant asteroid.

Four billion years ago,

the solar system was
a violent place.

KNOLL:
There was an influx of meteors,

and in fact there are craters
on Mars

into which you could fit
Australia.

NARRATOR:
The theory is, one object got
caught in Mars' orbit.

SUE SMREKAR:
There could have been a body

that was circling Mars
and circling Mars.

And it's possible

that asteroids circling Mars
created so much heat

and so much, um,
deformation inside

that it actually started
a dynamo.

NARRATOR:
With sheer tidal force,

the asteroid may have churned
the planet's molten core,

powering up its magnetic field
and its atmosphere in turn.

At least for a time.

What, then, went wrong?

So on Mars we ask the question,

well, where is
the magnetic field?

NARRATOR:
Earth's magnetic field
is one powerful cloak.

But that's not what the orbiters
find on Mars.

McCLEESE:
With the Mars Global Surveyor,
we put a magnetometer--

a very, very sensitive
experiment-- onboard.

We put it into close orbit.

And lo and behold, it found

the trace of an ancient magnetic
field on the planet.

NARRATOR:
Unlike Earth, Mars today has

countless small magnetic fields
pock-marking its surface.

Like shrapnel left
at a bomb site,

they seem like the aftermath
of some violent event,

one that may have also left
another clue at the scene:

Mars is misshapen.

SMREKAR:
We could see that
the Southern Highlands

were much more heavily cratered
and much higher.

The north is much lower,
much smoother.

NARRATOR:
Mars has a clear division
cutting straight through it.

The north is much less weathered
than the south.

The reason?

The leading theory is Mars
suffered a massive collision.

Perhaps that asteroid drew
too close.

McCLEESE:
I mean, this was big.

And the idea is that
this thing went, wham!

Right into the planet.

Pushed the atmosphere
away from the planet,

just literally blew
the atmosphere away.

The object may have changed
forever the south and the north,

making the two very,
very different.

And it may have been
the way, finally,

that the dynamo changed the way
in which it was operating,

and so the magnetic field
went away.

NARRATOR:
In one staggering blow, Mars may
have lost the driving force

behind its molten core
and its magnetic field.

Stripped
of its protective cloak,

the planet was forever
left exposed

to a searing assault
of solar wind,

preventing its atmosphere
from reforming.

In the areas where the rovers
have been traveling, it appears

that over three billion years
ago Mars was transformed--

from a warm, wet place, possibly
brimming with early life,

to an arid, acidic corpse.

But is it certain that any
and all life on the planet

was wiped out?

There's part of me, I must
admit, that would root

for the idea
of Martian life.

Is it impossible that life
exists on Mars?

No, but I think it's not
the odds-on bet.

I would take up Andy on his bet.

I think the chance of finding
life on Mars is high,

or I wouldn't be spending
my time and energy

searching for it.

NARRATOR:
Chris McKay holds out hope that
some organisms may have held on,

adapting to a harsher world.

Now, to find out if there could
be life on Mars,

he's headed for the ends
of the Earth.

McKAY:
We're on our way up into
the far north of the Arctic.

The polar regions are

a prime target for searching
for evidence of life.

NARRATOR:
It's summer at Axel Heiberg.

But, come winter, this island
can get down to 40 below.

McKay has come to study
a remarkable feature.

Here flow two springs that are
up to ten times saltier

than seawater.

Salt at this concentration
is usually poisonous.

Could microbes survive
these waters?

McKay has reason to think so.

On Earth, searching
for life is easy.

No matter where you look,
just about,

you find evidence of life.

NARRATOR:
To what lengths will life go?

It faces challenges
world over.

In the driest, hottest desert,
microbes thrive.

In the ocean's sunless depths
as well.

Even in the bowels of the Earth,

in caves seething with toxic
fumes and scalding acid.

At almost every limit,
life prevails.

Salty as the springs of Axel
Heiberg are, they harbor

miniature ecosystems.

McKAY:
We find a dark, rich soil
right above the ice

full of all sorts of bacteria.

It looks kind of like
the soil you find

in a forest floor--
it's that rich.

NARRATOR:
So if life is this resilient
on Earth, how about on Mars?

Could it have survived

on a planet stripped
of its atmosphere?

Somehow, somewhere could it have
adapted to harsher conditions

and found refuge?

Maybe we've just been looking
in all the wrong places.

The sites the rovers explored

were both along
the Martian equator.

But there's more to a planet
than just two spots.

SMREKAR:
Imagine if you just went
to Death Valley

or you just landed on the
arctic tundra, you know.

You would get incredibly
different view of the Earth.

Sure, where the rovers landed
could have been an acid wash.

Very salty.

Not very friendly to life.

But I bet if we landed
in another place,

we might find
something different.

NARRATOR:
It would have to be a place
that somehow retained

those same life-friendly
ingredients:

liquid water, not too salty
or acidic;

an energy source;

and nurturing organic molecules.

"Following the water" calls
for at least one more stop,

and this time, NASA is aiming
for a spot on Mars

where water may still exist.

We've long known the Martian ice
caps in the north and south

are made of carbon dioxide--
dry ice.

But some held out hopes
water lies beneath it.

In 2002, the satellite Odyssey
was able to peer

below the surface to tell
which elements are present.

Odyssey actually
discovered hydrogen

in the upper three feet of soil.

NARRATOR:
A vast reservoir of hydrogen,
marked blue here.

Could that "H" be a sign
of H2O?

If there's still water on Mars,
this is where to look for it.

It's time for the Phoenix Lander
to take up the hunt,

under the leadership
of Peter Smith.

SMITH:
The polar north on Mars

potentially was once
liquid water.

We don't know that for a fact;
we're going there to find out.

NARRATOR:
Tucson, Arizona,
is now Mars Central.

This is the latest image.

This is where it came down.

NARRATOR:
Unlike the rovers,

this robot is not just looking
for signs of a watery past.

It's taking the search for life
one step closer.

Its goal?

To look for water
and to assess habitability.

That is, in the past,

was the planet able
to support life, and did it?

NARRATOR:
Phoenix will focus
on one area and dig.

It's not designed to detect life
itself, but it can tell

if conditions here were once
right for it.

RESEARCHER:
Outstanding!

(excited murmuring)

NARRATOR:
The first "sol," or Martian day,
and already it looks

like the team has landed
in the right place.

SMITH:
This is the most ice-rich area
outside of the polar cap.

NARRATOR:
The lander uses a camera on
its arm to peer under itself.

It discovered that the descent
thrusters had, by chance,

cleared a patch of soil away,
revealing what might be ice.

SMITH:
This is an interesting place
we've landed.

If you came out here
with a broom,

you could sweep off that...

it's only two inches of soil
over ice.

You could actually sweep off
all that soil off into a corner

and you would have
almost a skating rink

with some interesting bumps
on it.

MAN:
Hey, Matt, did you see

the color picture
of what UA dug up?

No-- no, I haven't.

Unidentified white stuff
in there.

Oh, wow!

NARRATOR:
But whether it's carbon dioxide
ice or water ice

or something else
is the question.

That white stuff, wow!

This material
we think is ice.

SMITH:
We found some very bluish
ice-like material

that has the science team
arguing incessantly

about whether it's ice or salt
or some other exotic material.

That's not permafrost.
That is ice.

NARRATOR:
That bluish, ice-like material
turns up as nuggets

in a ditch Phoenix dug.

The team intentionally leaves
the area undisturbed

and watches.

These two...

MARK LEMMON:
We were trying to put the
pictures up on the screens

as fast as we could, compare
them to the pictures

that we'd taken
a few days before.

And it just took seconds
of looking at the picture

to say, "Yes, stuff has
changed."

NARRATOR:
Lo and behold,
the clumps disappear.

Oh, is that pretty.

NARRATOR:
The reason?

They vaporized.

That wouldn't happen
to carbon dioxide ice--

not at 26 below zero.

Only water is going to actually
sublimate away

at those temperatures.

We watched it
just poof, go away,

over the course
of a couple days.

NARRATOR:
For the first time, we have
touched water on another planet.

And yet, how does that help
the chances for life on Mars?

Microbes need liquid water.

Is the Martian north hiding
that somewhere?

McKAY:
Phoenix is the first Mars
mission ever

to actually come in contact
with real H2O.

It's ice, but there it is.

Water, frozen solid.

And the question then is,
was it ever liquid?

NARRATOR:
Phoenix can find out.

The robotic lab has
an instrument onboard

that can detect if the soil here
has come in contact

with liquid water.

It's called TEGA, and it can
distinguish different chemicals

by heating them in a small oven.

Each boils off
at a different temperature.

Let's do another tool-frame
rotation of negative point one.

Minus point one tool frame.

NARRATOR:
Working with an exact model
of Phoenix,

the team's been running
simulations in Arizona

with dirt that's dry
and granular--

characteristics they expect
Mars dirt to have.

All they need now
is to get Phoenix

a scoop of the real thing
so TEGA can run its test.

RESEARCHER:
The right stuff slid.

It's the stuff on the screen.

NARRATOR:
Sample after sample
is delivered.

But
to the TEGA oven below.

There's the full ten-minute
shake right there.

Okay, so the bottom line is
we didn't get any dirt.

NARRATOR:
Martian soil is
surprisingly sticky.

SMITH:
Well, the TEGA instrument
has not been

a stellar performer,
unfortunately.

It's had a lot
of little problems.

Now, are these
just growth pains

or learning difficulties,

or is it really an instrument
on the way out?

This has been
a very emotional ride.

NARRATOR:
The best minds in space science
are devoted to one thing:

getting dirt past a screen.

So far, the dirt is winning.

Finally...

The TEGA oven
is full!

No!
Really?

Yay!

It's been a long
time coming,

but boy it's sweet
when it's here, right?

WOMAN:
Okay, can we
be happy now?

We can be happy now.

NARRATOR:
Soon there's more reason
to be happy:

TEGA's ovens turn up
carbonates--

chalk-like minerals that form
in the presence

of liquid H2O.

Water-- liquid water--
was at this spot on Mars.

But how could that be?

Temperatures recorded
in the Martian polar north

have never gotten
warmer than 13 below zero.

How could the ice here
have ever melted?

Another satellite, the Mars
Reconnaissance Orbiter,

found a clue.

Probing the polar cap
by bouncing radio waves down,

like sonar, it discovered
distinct layers of dust and ice,

laid down through a succession
of climates, colder and warmer.

McCLEESE:
How do you get layers
on planets?

Well, you get cycles
of hot and cold

over the surface of the planet.

NARRATOR:
And what makes the temperature
change so much?

That happens over phases
that last millions of years,

as the globe tilts more or less
toward the sun.

A planet spins like a top.

The Earth has a large moon
that helps to stabilize it,

so it rotates relatively
steadily.

But the two moons Mars has
are both small,

so it's more prone to wobbling.

Over the course of millions
of years, it can tilt a lot.

Five million years ago,

the Martian north pole was
angled at 45 degrees.

McKAY:
So the amount of sunlight
that it receives in a day

would be twice what it's
receiving now.

So imagine five million
years ago

it could have been as warm as
the polar regions on Earth.

NARRATOR:
This part of Mars
may have been warmer

as recently as five million
years ago--

long after the planet's
atmosphere got ruined--

warm enough to be wet.

Did that make the north
life-friendly?

Not if conditions here were
extremely acidic or salty,

like where the rovers landed.

To find out how life-friendly
this area was,

Phoenix will use a second lab,
called MECA.

It will test its sample's
properties not by heating it up,

but by adding water
it's brought along.

MICHAEL HECHT:
It stirs it up to determine
what comes out of the soil,

what kind of tea does this
Martian soil make.

(all chatting)

NARRATOR:
Step one is getting
a sample into a cell.

After TEGA's troubles, no one
is taking that for granted.

I don't see anything
changing down here at all.

NARRATOR:
Looking at the visuals
from Mars,

it's hard to tell if the soil
actually got delivered.

The team can only hold out hopes
their experiment is underway.

SUZANNE YOUNG:
Just waiting,
that part was agony.

Every second was an hour.

It was definitely the longest
hour of my life.

NARRATOR:
Then...

All right, here we go.

There it is.

More is coming.

HECHT:
When that first data comes down
from Mars and you suddenly see

these wiggles on the screen

just like you've seen
in the laboratory,

the sense of astonishment is
indescribable, just seeing it.

We know for the first time
the pH of Mars.

NARRATOR:
The pH-- the level of how acidic
the soil is.

I want a number
from zero to twelve.

HECHT:
Something that people have been
speculating about

for years and years and years.

Give us a number
from zero to twelve.

NARRATOR:
There's a surprise...

It's basic.

It's basic?

NARRATOR:
It's not acidic--
a reading of 8.3,

the kind of soil asparagus
could grow in.

So far, so good for life.

Next, what's that salt content
in the sample?

HECHT:
Beautiful!

(laughs)

Oh, that is
gorgeous.

NARRATOR:
It's unexpectedly low.

Another plus for life.

McKAY:
At the Phoenix site

we find relatively pure ice.

We find neutral conditions.

We find salts,
but at low levels.

SAMUEL KOUNAVES:
For a lot of us
it's a new view of Mars.

It obviously is not super salty,

it's obviously not super acidic
or super basic.

Bacteria might enjoy this stuff.

So some organisms
might be able to survive

if the other part of
the environment was good.

NARRATOR:
But that's a big if.

Just when all readings
are pointing

to a life-friendly environment,
one comes up that's baffling.

HECHT:
After the initial analysis,

that's where things started
getting truly interesting.

Michaelina, take a look at this.

NARRATOR:
There's an unexpected chemical
called perchlorate.

HECHT:
It was about the farthest thing
from our imagination

that we might find there.

NARRATOR:
On our planet, perchlorate
is a toxic chemical

manufactured for rocket fuel
and fireworks.

It's rare in the natural world,

except in the most forbidding
deserts on Earth.

HECHT:
This stuff, liquid perchlorate,

is not a material that microbes
can very easily live in.

It's not a very friendly
environment.

KOUNAVES:
Life can survive

in pretty harsh conditions,
but there are limits.

NARRATOR:
What are the chances of life
amid perchlorate?

It's a new question
for Mars scientists.

Not for John Coates.

COATES:
People have said that the
presence of perchlorate on Mars

is indicative that life couldn't
be present,

that this compound is too toxic.

But that statement is not true.

NARRATOR:
At a lab in Berkeley,
California,

Coates and his team have been
quietly studying

a group of microbes that is
about to attract some attention.

These are his subjects--

organisms that thrive
on perchlorate,

consuming it as we do the air
we breathe...

a trait that could come in handy

on oxygen-deprived Mars.

The Martians we've long sought
may be like these bacteria,

called dechloromonas.

COATES:
We would never have thought of
looking for organisms like this

on Mars.

Now that we know that this
compound is present on Mars,

it certainly opens up
that as a life-form

that could potentially have
existed on Mars.

NARRATOR:
Could dechloromonas
or its alien counterpart

have ever stood a chance
on Mars?

Phoenix will never know.

Its experiments done,
the team disperses.

As the Martian polar night
descends,

the lander's solar power
dwindles.

Phoenix will soon be entombed
in dry ice, never to awaken.

The search for signs
of Martian life

will fall to the next mission.

The Mars Science Lab-- MSL--

will be the size of a small car.

It will be bristling
with technology...

an array of imagers,
sampling tools and labs

that will make its predecessors
seem quaint.

McKAY:
I'm very excited about MSL.

In an interesting way,

it's a complement
to the Phoenix mission.

To me, we've already
followed the water.

We know there's water on Mars.

Check on the water.

The next thing we need to do

in terms of a strategy for life
search is follow the organics.

Find organics.

NARRATOR:
We have come a long way in
meeting our neighbor next door.

We've gone from envisioning it
as barren and moon-like

to a place as diverse
as it is familiar.

A world that could well have
harbored life.

We can now imagine the day,
billions of years past,

when two planets took their turn
round the sun,

neck and neck in the race
to claim life's course.

We know what happened on Earth.

But the other was dealt a blow.

If there's proof on Mars
of a life-filled past,

it is still waiting
to be discovered.

On NOVA's "Is There Life
on Mars?" Web site,

check out our Q&A
with a NASA astrophysicist,

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and slideshows

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