Horizon (1964–…): Season 49, Episode 2 - Mission to Mars: A Horizon Special - full transcript
This is one of the most
sophisticated space vehicles
ever built.
Curiosity is a billion-dollar rover.
In six days' time, it will attempt
to touch down on Mars.
Landing a big rover
is a tough business.
It means that everything
about the system gets bigger
and therefore harder.
This will be no ordinary landing.
It will be winched down by a crane
hovering in the Martian sky.
It's so ambitious, it's so
audacious, it's so unconventional.
Horizon has been behind the scenes
with NASA's team as they follow
their rover across
350 million miles of space.
When Curiosity comes over
the horizon,
this guy is already pointed
that direction and as she comes up,
then we're talking.
Curiosity's mission is to discover
if Mars could ever have
supported life.
But the Red Planet has become known
as the Bermuda Triangle of space.
Two-thirds of missions there
have ended in failure.
In just under a week,
the world will learn
if Curiosity can overcome the odds
and touch down on Mars.
SPEECH OVER RADIOS
It's 10pm at the Jet Propulsion
Laboratory in California.
OK, copy and we'll make that report
to the surface team
when they come onboard.
The team behind the Curiosity
mission are locked
in a crucial test at
the space flight control centre.
We're now about five and a half
minutes to entry.
They're practising for a landing
they know is the most audacious
ever attempted on another planet.
Three minutes to entry.
They've been rehearsing and testing
day and night for months,
running through each individual
step of the mission in
painstaking detail.
Confirming that we have
parachute deploy.
Brian Portock is the flight director
for the 350 million-mile
journey to Mars.
Ann Devereaux helped devise a way to
stay in touch with the rover.
Adam Stelzner will mastermind
the daredevil landing.
And leading this test is
Chief Engineer, Joel Krajewski.
The fate of this mission is central
to everybody's soul, really.
Most folks have worked on this for
three years, five years, eight years.
You don't get to do many
in a given career.
You only get to do a few
if you're lucky.
So the stakes for everybody are
as high as they can be.
This is just a rehearsal,
but on the 6th of August,
they'll be doing it for real,
hoping the Curiosity rover
will arrive safely at its
destination.
Mars, the Red Planet.
It's become known as
the Bermuda Triangle of space.
Since the launch of the first
rocket there in the 1960s,
two-thirds of all missions
have ended in disaster.
The mission logs make scary reading.
"Failed to launch."
"Missed the planet."
"Lost radio contact."
"Lost on arrival."
The team knows Curiosity might never
reach the surface of Mars.
It's Joel Krajewski's job to make
sure this mission is a success.
His day may begin like
many Californians...
but then he heads to
NASA's Jet Propulsion Laboratory.
Like anyone else,
I drive into work every morning
but every morning as I do so,
I pinch myself because
I get to work on a space mission
and that is, that is pretty cool.
For more than a decade,
Joel has been engineering rovers
to send to the Red Planet.
Before I got into working on rovers,
of course like anybody else
I thought it was going to be
a kind of a tricky business.
It sounds hard throwing things
up into space
and exploring other planets.
Once I got into it, I learned that
it's even harder than I thought.
This is the third rover that
Joel has worked on.
But even for a Mars veteran
like him, Curiosity
has been a huge challenge.
Curiosity is the most complex vehicle
we have sent to Mars.
Hundreds of people have worked on it
for more than eight years
and we're still working on it.
Different people understand
different aspects of it,
but nobody knows it all.
As the real Curiosity hurtles
through space,
its clone is hidden in a garage
at the Jet Propulsion Laboratory.
It runs on its very own
nuclear generator.
Its components can withstand forces
greater than those
exerted on a supersonic jet.
And its electronics are designed to
work at temperatures far lower
than the coldest places on Earth.
It's the most advanced moving
vehicle ever sent into space.
Today, Joel's team are testing
the wheels of Curiosity's twin.
They're low class.
Is that what we call them?
That's what we call them.
It's just one of hundreds of tests
the rover has been through
in the past nine months.
That's great.
The scientists want to land on
Mars and explore.
They want to explore where we land
and then also explore
kilometres away from where we land,
and that means we have to drive.
We'd like to be able to drive
over big rocks
so that we can drive close to
a straight line,
not too much meandering around, and
therefore we designed a big rover.
That makes it tricky.
The reason Curiosity is so big
and expensive
is because of the science it will be
conducting on Mars.
It will have to
drive across difficult terrain
while carrying a lab full
of equipment.
The scientists would
like an infinitely capable vehicle.
But in the real world, the machine
has to fit within a certain volume.
It has to fit within a certain mass.
We can only lift
so much mass off the Earth
and have it land safely on Mars.
The rover is five times as heavy as
any vehicle they've ever launched,
which makes landing
it on another planet
more difficult than anything
they've attempted before.
Landing a big rover
is a tough business.
The landing system is more complex,
parachutes are bigger,
everything gets much bigger
and therefore harder.
# There's a starman
waiting in the sky... #
NASA's engineers have never shied
away from tricky landings.
# There's a starman... #
During the Apollo
missions of the 1970s,
they weren't satisfied just to
put a man on the moon.
But landing a car on Mars is
an entirely different proposition.
Adam Stelzner has spent years
working out how to do it.
He will take control of the rover
as it begins to enter
the Martian atmosphere.
He won't be able to rely
upon the systems
that got the lunar rover down safely
onto the surface of the moon.
Mars is tough.
The moon, where we've landed lunar
modules on the moon before,
does not have any atmosphere
and it makes the process of getting
down to the surface kind of simple.
You take a rocket engine, you turn
it on and you slow yourself down
until you touch down on the surface.
Unlike the lunar rovers,
Curiosity will have to battle
an unpredictable atmosphere.
Historically, Mars has been evil.
You don't know what the weather's
going to be like, you don't know
whether the atmosphere's going
to be dense or diffuse.
Will it be a hot day and not
so dense, or a cold and dense day?
If it's cold and dense, you slow
down faster, you end up shorter.
If it's hot and low density,
you end up flying farther.
The dangers of this unpredictable
atmosphere are heightened
by the speed the spacecraft
has to travel at to get to Mars.
It will arrive at
13,000 miles per hour.
We have enough energy of motion
in the spacecraft that we could
vaporise the spacecraft
in the atmosphere of Mars
just by slamming into that
atmosphere and developing
so much friction that
the vehicle would burn up.
So it's a challenge.
The rover will be
tucked inside a spacecraft
when it reaches the dangerous
Martian atmosphere.
Its first line of defence will be
the world's biggest heat shield.
Next, the team have to stop it
from crashing head-on
into the Red Planet.
So they have designed the biggest
supersonic parachute ever made.
In NASA's giant wind tunnel near San
Francisco, they put it to the test.
'Five, four, three, two, one...'
The parachute must be deployed
at twice the speed of sound.
Good chute, good chute!
The tests confirmed the huge canopy
should survive the enormous forces
it will encounter as it's dragged
through the Martian atmosphere.
Finally, Curiosity's engineers
tested the most risky part
of the landing procedure...
I think we are ready to go.
..a bizarre hovering crane
that will have to lower the rover
down the final 20 metres
to the surface.
CHEERING
The sky crane took the engineers
years to perfect.
It has never been used to land
anything before.
But although all of Curiosity's
individual landing stages
passed their tests on Earth
before launch,
they have never been tested
all together.
The Red Planet's evil environment
will be the first place the whole
procedure is ever attempted.
MUSIC: "Pumped Up Kicks"
by Foster The People
Planning the journey was the first
challenge for Joel Krajewski's
engineering team.
Go, go, go, go, go!
Nice job!
APPLAUSE
As Flight Director, Joel's colleague
Brian Portock is, in effect,
the mission's quarterback.
CHEERING
# Robert's got a quick hand... #
It's Brian's job to aim and throw
the spacecraft across the solar
system to a moving receiver...
..Mars.
PLAYERS SHOUT
Everything's in motion in space.
Run in, run in!
Mars is moving round the sun and the
Earth is also moving round the sun,
and their motion relative
to each other is changing.
Go, go, go, go!
Similar to a receiver running out
for a pass is in motion...
Ball!
..and the quarterback needs to
stand back and throw a ball...
Really good shot!
..so that the receiver and the ball
meet at a point in space
and a time that's the correct one
so that they can catch it.
Oh, nice!
CHEERING
They need to figure out how far
the ball needs to travel depending on
where the receiver is.
Go, go, go! How fast the receiver's
running in that direction.
Most quarterbacks don't sit down
and calculate that on paper.
Set, go!
It's all done in their head
instinctively,
without thinking about it.
For spacecraft, we do it on paper,
or these days, on computers.
PLAYER SHOUTS
The other thing a quarterback does
is put spin on the ball.
Spiral so that the ball flies
in the correct trajectory.
So we also are spinning
our spacecraft...
so it maintains its attitude...
..and so that we can point the solar
rays back at the sun and communicate
back to the Earth.
And so, the actual rotation
of the ball
is similar to the rotation
of the spacecraft.
They make it sound simple,
but firing a spacecraft
across the solar system
involves some really complex
ballistic calculations.
The craft must escape the pull
of the Earth's gravity.
It must contend with solar winds
that could blow it off course....
cosmic radiation which can
disrupt radio contact...
..and the craft is constantly being
dragged from its course
by the gravitational pull
of other planets.
Just a tiny error could result in
Curiosity missing Mars altogether.
To get the distance scales
approximately similar,
the quarterback here is throwing
a pass 30 metres, 40 metres away.
Brian's target of Mars is hundreds
of millions of kilometres away.
It's similar to if this quarterback
here were throwing a football
to a receiver in, say, London,
and needing to hit his mark.
APPLAUSE
It'd be the wrong kind of football.
LAUGHS: Yeah!
In November 2011,
at Kennedy Space Centre,
the rover made its way to the
launch pad on an Atlas rocket.
For the mission team, the launch
is the moment of no return.
While the craft is on the ground,
final fixes can always be made.
But once it's in the air, a fault
could mean the end of the mission.
There's so much energy involved
with launching.
SPACECRAFT BLASTS
All the little piece parts
on the spacecraft
are designed to survive
that vibration and those forces.
Just the fact that it gets into space
and we start talking to it
for the first time
is an incredible achievement.
It's spacecraft separation.
APPLAUSE
It's the first big step
on the way to Mars.
But any damage caused by the launch
to Curiosity's components might not
be immediately obvious.
So, for the past eight months,
the engineers have needed to stay
in careful contact,
to check its course
and its vital signs.
'Re-transmit...
Six, three, eight...'
They need to be sure that they
receive every message sent back
by the rover...
and that every instruction they give
will be heard loud and clear.
MUSIC: "Sweet Child O' Mine"
by Guns N' Roses
To communicate with Curiosity,
the team have to rely on equipment
hidden deep in the Mojave desert.
Ann Devereaux helped engineer
the systems that allow the team
to stay in touch.
Now that the spacecraft is nearing
the end of its voyage,
she feels the distance between her
and her rover more than ever.
It's very much akin
to having a kid in college.
We raised her,
we taught her everything she knows,
we gave her all the gear that she
needs to investigate her new world,
but now she's gone.
And, you know, we gave her a calling
card. We told her to call often,
but we don't get to talk to her
all the time, and, you know,
we don't know what she does every
day until she's in contact with us.
# Whoa, whoa, whoa
Sweet child o' mine. #
Curiosity can call home using two
ultra-high-frequency radios.
But the distance between Mars
and Earth,
together with the rover's
limited power,
makes it difficult
to pick up the signal.
It's a problem anyone with
a car radio knows well.
RADIO INTERFERENCE WARPS MUSIC
We're about a hundred miles outside
of Los Angeles.
In the car,
I've got the radio going,
but my favourite radio station
is almost gone.
I'm not that far,
certainly compared to Mars,
and the radio station that I listen
to has a 90,000-watt transmitter,
and so you'd wonder why I can't
pick up the station here.
The problem is my little antenna
is just not capable of picking
up the signal at this distance,
no matter how powerful it seems
the transmitter back at home is.
MUSIC: "Spread Your Love"
by Black Rebel Motorcycle Club
In space, power is in short supply,
and Curiosity will need to use
almost all of its energy
to drag its near-ton weight
across the surface of Mars.
That means the rover's transmitters
have to get by with just a fraction
of the 90,000 watts used by
a radio station on Earth.
She only has a ten-watt transmitter,
and she's MUCH further away.
We're about 140 kilometres
from Los Angeles -
Curiosity is going to be 250 million
kilometres at Mars.
We need something bigger
for an antenna.
# Spread you love like a fever
# Spread your love like a fever
# Spread your love like a fever
# Spread your love like a fever. #
The DSS14 antenna
is the biggest dish
in NASA's Deep Space
Communications Network.
It's their switchboard for every
spacecraft in the solar system.
But all this interplanetary chatter
means that Ann can't just pick up
the phone to Curiosity
any time she likes.
There's a lot of spacecraft out
there, and they all want to talk
back home, too, right?
They all want to call home.
And so, we have to schedule time
at one of these antennas,
like here at DSS14,
and tell the people that we need to
talk to Curiosity and this is how
long we want to talk to her for,
and they point the antenna so when
Curiosity comes over the horizon,
this guy is already pointed in that
direction and as she comes up,
then we're talking.
But a queue for the phone is not
the only thing that could kill
the conversation between the rover
and the team back home.
Once it arrives at Mars,
the whole mass of the planet
will stand in the way.
Mars itself rotates
as the Earth rotates,
and so sometimes, even if we wanted
to talk to Curiosity, we couldn't.
Because we just have the whole
planet between us and Curiosity.
A Martian day lasts 24 hours
and 40 minutes.
For half of that time,
the rover will drop behind
the red planet's horizon,
out of view of Earth's antennas.
When Curiosity arrives,
night will be falling on Mars.
Midway through its perilous
landing procedure,
the team will lose direct contact
with the spacecraft.
But NASA can rely on help
from some previous Mars missions.
We have an ace in the hole.
In fact, we have two.
It's called Mars Reconnaissance
Orbiter and Mars Odyssey.
So, these are two orbiters
that we have around Mars already.
They're sitting there, they're
waiting for their sister to come.
As the Martian night obscures
the rover from Earth's view,
Odyssey will attempt to relay
its vital messages
back to the control room.
This is just one of hundreds
of risky procedures
that must go right
for Curiosity to land safely.
In designing the most complex
landing ever attempted in space,
the team have had to go out on
a limb, staking their reputations
on a system that has
never been used before.
It's so ambitious. It's so
audacious. It's so unconventional.
It doesn't feel like
there's a lot of shelter.
You can't say,
"Oh, I'm doing what they did before
"and it just didn't work out,
I didn't get lucky."
No, we're not doing what we did
before.
We're doing something completely
novel, hanging it way out there.
Um...
You feel exposed.
As chief architect of Curiosity's
landing sequence,
Adam Steltzner has gone through
each part of it
over and over in his head.
But for now,
it only exists in his imagination.
And in this NASA animation.
We show up at this
near six-kilometre-a-second speed.
We burn a hole in the sky of Mars
for about 100 kilometres long.
We start out
at six kilometres a second,
and we're still going
about a kilometre a second.
We're not slowing down very
much, because there's not enough
atmosphere to help us out.
So eventually we have to pop
a parachute.
That slows us down more.
But still not enough.
It takes us down to about
100 metres a second.
200 miles an hour, almost.
You don't want to hit the surface
of Mars like that.
So, about a couple of kilometres
from the surface,
we decide it's time to look
for the surface with our radar.
And once we've seen it,
we take this great leap of faith.
And cut ourselves free,
light our rockets and start
our descent to the surface.
We slow ourselves all the way down,
and then, 20 metres above
the surface,
we do this kind of crazy thing...
called the sky crane manoeuvre.
Zzz-zzz...
The average person on the street
thinks it's crazy.
Even the team that's working it,
sometimes we think it's crazy.
The strange part is,
it's actually the result
of reasoned engineering thought.
Six days from now,
the team hope Curiosity will execute
this unlikely manoeuvre.
Back on Earth,
they will be waiting for the message
they have all dreamed of...
..it's safely down.
The purpose behind all this
daredevil engineering
is to send the biggest payload
of scientific equipment
ever to leave Earth
to uncover the secrets of Mars.
It's the latest step
in mankind's love affair
with this curious red light
in the night sky.
Ever since Galileo
built his first telescope,
astronomers professional
and amateur alike
have peered through their lenses
at the red planet.
Oh, yes.
Do you see it?
I see it.
I see some bright colours.
You see some bright colours?
I think it's Mars.
You think it's Mars?
I think you might be right.
It's Mars, for goodness' sake - now
how could you not be interested?
It's just beautiful.
Mars has, you know, intrigued people
for so many years.
I think it's that red colour
that attracts people,
and it's just...
just the romance of it.
That's wonderful.
Curiosity's planetary scientist
Ashwin Vasavada
has shared this fascination
since he was a boy.
Looking at Mars through a telescope,
you can see some wonderful things.
You can see the planet,
you can see the polar caps come
and go with the seasons.
I love looking through telescopes,
but really, they're almost like
using a record player for someone
who grew up with the internet.
In 1976, we moved beyond
mere telescopes.
When the Viking space probe
beamed back the first-ever images
from the surface of Mars,
it inspired a whole generation
of space scientists.
This image is an image taken
by the Viking lander in 1976,
and it kind of is a special image
for me,
because I saw this image in a book
I was reading as a young kid.
And it's the first time
I really noticed that planets
were other worlds.
You could stand on a planet,
look out and see rocks
and you could walk off the horizon
of the image you're looking at,
and you wonder
what's across that hill.
It just blew me away, and maybe
it's the moment I became
a planetary scientist.
The Viking mission tapped into
the public's fascination with Mars.
It was inspired by one of the most
intriguing questions in science.
Are we alone?
It's about searching for life
in the universe,
it's about asking this profound
question of whether we're alone,
whether we're all that there is.
And the only way we can do that,
even in this technological age,
is just by stepping out
to our nearest neighbour planet,
the one next furthest out from the
sun, and asking the question there.
But really, it's going to tell us
this profound reality,
whether we're alone or we're not.
NASA's Viking mission
was hugely ambitious.
It was their first ever attempt
to land robotic probes
on the surface of Mars.
And it was going to search
for life itself.
It has an arm, so it can extend
out into the area around it
and pick up sand to bring back
to the other laboratories
which are on board the lander.
The Viking landers were equipped
with these state-of-the-art
biological laboratories
and they scooped up soil
and analysed it.
They tried to feed any microbes
that would be in the soil
and do very sophisticated
experiments to detect life.
CHEERING
The delight of landing safely
and receiving these
extraordinary pictures
was followed by what seemed to be
an incredible discovery.
Initial observations suggested that
they had detected microbial life
in the Martian soil.
But as the euphoria subsided
and the scientific data was
analysed, a new realisation dawned.
Viking had in fact failed
to find life on Mars.
And the results were either
negative or just ambiguous
and it made us realise that
it's not going to be this easy.
Since the 1970s, other missions
have told us much more about Mars.
Successful Rovers and orbiters
have produced detailed maps
of the red planet's surface
and breakdowns of its atmosphere.
They have revealed just how hard
it would be for life to survive
in the planet's extreme environment.
The surface of Mars today
is a very harsh place to life.
There's a lot of things
that are hazards to life.
Now we're interested in knowing
whether those same hazards
were there in the past
and maybe early Mars as opposed
to present Mars was the place
to look for life.
Today, Mars is
an inhospitable desert.
Its thin atmosphere leaves
its surface exposed
to lethal solar
and cosmic radiation.
Average temperatures of minus 55
degrees Celsius
would make it very hard for life
as we know it to survive.
That's why Curiosity is not
expecting to find life here and now.
Instead, it will try to discover
if life could have survived there
millions of years ago.
Which means the Rover not only
has to travel all the way to Mars,
it has to travel back in time.
This desert, 200 miles
outside Los Angeles
has become a second home
for the Curiosity team.
It's an ideal place not
just to test the Rover,
but also to design
the mission's science.
Chief scientist John Grotzinger
is in charge of the experiments
that will enable the Rover
to see into the past.
Not by looking for bones or fossils,
but by trying to find
elements crucial for life.
Simple things,
like liquid water.
What we're going to do
is an acid test.
Take a few drops, put it on the rock
and see if it fizzes.
And yes, cool, it fizzes.
And what that tells us is that
this work is made out of
a mineral called carbonate.
And carbonates on Earth
form in lots of water,
and that tells us that this dry
desert that we are in here today,
600 million years ago,
there was an ocean.
It was liquid water
in ancient lakes and seas
that allowed life to take hold.
So Curiosity's scientists
have carefully chosen
a Martian landing site
similar to this spot
in the Mojave Desert.
Curiosity will hunt for the same
evidence of a wetter past
in the Gale Crater on Mars.
Here's Gale Crater, with Mount Sharp
majestically rising above the plains.
Mount Sharp is a Martian mountain,
rising 18,000 feet above the centre
of the massive Gale Crater.
The scientists believe their Rover
could find carbonates here, proving
this Martian crater was also filled
with water in its ancient past.
But that's not the only similarity
that Mount Sharp has
with the mountains
here in the Mojave Desert.
In both places, the team can use the
rock itself to travel back in time
to any moment
in the geological past.
The mountains are formed of layers,
built up gradually over millennia.
Testing each one will reveal
what the environment
was like there
at the particular moment in time
it was laid down.
What we see here is
a stack of layers that tell us
about the early environmental
history of the Earth,
representing
hundreds of millions of years.
They read like a book of
Earth history and they tell us about
different chapters in the evolution
of early environments and life.
And the cool thing about going
to Mount Sharp at Gale Crater
is going to be there,
we'll have a different book
about the early environmental history
of Mars that will tell us
something equally interesting, and we
don't know what it's going to be yet.
The team believe the place
they've chosen to land is
the perfect spot
to look back in time.
They want to know if Mars
could have supported life
at any point in its history.
So that Curiosity can discover
all the information
the scientists need,
the engineers have designed it
to work just like
a human exploration team would
back here on our own planet.
What Curiosity can do
as we begin to explore Gale,
is pretty much what
a geologist would do on Earth,
but it's also bringing along
a chemistry lab.
The official name of the mission
is Mars Science Laboratory.
And with good reason.
We have three different
camera systems.
We have another instrument that
involves a laser that gives us
the ability to zap out
and understand
the composition
of the environment around us.
We've got instruments that can ping
things down in the subsurface
and tell us if there's water
down there.
And then we've got other instruments
that can actually tell us
about the laboratory conditions,
like what we would do on Earth.
It's this chemistry lab,
right in the belly of the Rover,
that makes the mission
really special.
What Curiosity can do,
which has never been done before
on a Rover mission,
is to actually drill a hole
in the rock,
take the powder and put it
into the chemistry laboratory
which is inside the Rover.
And that I'm really excited about,
because it takes us
to a whole other level
with science analysis on Mars.
This is a clone of
an essential piece of Curiosity's
mobile chemistry kit.
It was constructed here
at the Goddard Space Laboratory
by planetary scientist Paul Mahaffy
and his team.
This equipment, known as SAM,
can reveal the chemicals
present in the Martian rock.
But for it to work,
SAM needs to be fed the right sort
of rock samples, correctly prepared.
So Curiosity will first have to use
all the other tools it has
at its disposal.
The very first tools are
the very high resolution cameras
on the mast of Curiosity.
And then, when we get even closer
to a sample
that we might see in the distance
and then approach,
we'll start using other tools.
For example, on the mast is
an experiment
called ChemCam.
ChemCam will point at a rock
and fire a laser.
And then look at the emissions
that come off from that rock,
and that's really important
because it can tell the differences
between different types of rocks.
So if we come across a rock
that looks substantially different
from rocks we've looked at before,
then we might want to approach
those samples,
put out the arm,
and start interrogating that rock
or that outcrop
with instruments that are on the arm.
An element analyser
and a very nice microscope,
and if we examine the outcrop
or the rock with those tools
and decide it's worth
even further exploration,
then what we do is
we sample the rock.
We drill into the rock, we create
some powder with the sampling system
and then we deliver
that powder into SAM.
The chemical analysis
of this powdered rock
is one of the most important tests
in the mission.
That's why the team are still
running tests on SAM's twin
back here on earth.
We've put a bit of powdered rock
into the oven of SAM,
and we slowly heat it up
from ambient temperature
to very hot temperature,
about 1,000 degrees centigrade.
And as the sample is heated up,
at different temperatures it releases
different simple gases or complex
gases, and that helps us determine
what the mineralogy, what the
mineral composition of the rock is.
SAM can look for the chemical
signatures of water
and it can also detect
organic compounds -
the building blocks of life.
Our very first job on getting
to Mars will be to understand
if there are organic compounds
that we can even detect.
Mars is a very harsh environment.
Ultraviolet radiation penetrates
right down to the surface
because there is less of
an atmosphere than on Earth.
The same is true for very energetic
cosmic radiation
that pounds in and really has
the potential to destroy
fragile compounds that are
very close to the surface.
So that's a very first-order
question -
are there organic compounds on Mars?
Can we detect them with SAM?
And if there are,
then the fun really starts.
The discovery of organic compounds
on Mars
would cause huge excitement
right across the globe.
Together with liquid water, they are
regarded as essentials for life.
Curiosity's other tests will reveal
whether the ancient
Martian environment
could have allowed life itself
to form from these building blocks.
Even in the best-case scenario,
the environment on early Mars would
still have been pretty hostile.
So to understand if extraterrestrial
life could have formed,
astrobiologists like Lewis Dartnell
need to find out
the most extreme conditions
in which life could still survive.
They do it by looking for the limits
of life here on Earth.
Searching out harsh,
dangerous environments,
places where we used to think
life could never exist.
A lot of what we're trying to do
is understand the limits
of terrestrial organisms.
What's the survival envelope
of Earth life, so places
that are very hot and acidic
or are very cold and dry,
like Antarctica,
or some very high-pressure,
very high temperature places,
like the black smokers and the
hydrothermal vents on the sea floor.
Because it's by understanding
life in these most hostile
environments on Earth
that we understand a lot about
the possibility of there being life
on other worlds,
and in similar environments.
This decaying train line is one of
these hostile environments on Earth.
It's a strange, alien landscape,
cut through by one of the world's
most extraordinary rivers.
Now, that's...
That is blood, blood-red.
That's incredible.
The Rio Tinto is
100 kilometres long,
running from the mountains of
Andalusia to the Gulf of Cadiz.
It is been used by NASA
to test life-detection equipment
for Mars missions.
Rio Tinto is one of those places that
you read about time and time again.
It's commonly used as an example of a
Mars-like environment here on Earth.
I've seen loads of photos in journal
papers and books, textbooks,
but it's only when you come here
and see with your own eyes
that it just jumps out at you.
That is... That is an alien colour
for a river, that is, blood red.
To understand what Mars might have
been like millions of years ago,
astrobiologist first try
to understand these desolate
places on earth.
Actually, the reason that the waters
here in Rio Tinto are blood red
is because the substance
is the same.
The oxidised iron in our blood
is the same stuff as in that river
turning it that grotesque,
off colour.
It's absolutely amazing.
It had always been thought
that this strange red colour
was a result of pollution,
that the water had been tainted
by iron and other metals
washed downstream from the mines
that have existed here
since Roman times.
Well, I can't see anything
obviously alive,
and there's clearly
no fish swimming around in here.
There are no visible signs of life.
And the Rio Tinto's waters
hold another secret,
which made people think
there was no hope
of even the tiniest life forms
ever existing here.
So, I've got a PH meter here,
and I'm going to test the acidity
of the water in the Rio Tinto
at this place here.
Now, a normal river,
a healthy river, would be PH7 -
that's neutral.
And, obviously, the lower the
number, the greater the acidity is.
So I'm going to take a sample...
here...
..dunk in the PH probe and we see
that it's dropped below 3 already,
2.7 and it's levelling off
at about 2.65, so that's acidic.
That's about 100,000 times
more acidic than a normal river.
And that's almost as acidic
as stomach acid.
That is one acidic river.
If liquid water
ever existed on Mars,
it might well have been
a metallic acid river like this.
It seems unlikely to think that life
could have emerged
in such a hostile environment,
but scientists have discovered
this blood-red river
is actually teeming
with microscopic bacteria.
This is a microscope photograph
of the river water
and you can see these thin,
hair-like threads
down the microscope, and these are
the microbial filaments themselves,
these are the cells,
these are the life in this water.
These extraordinary bacteria
are not just tolerating
the strange river conditions -
they're actually creating them.
They simply don't behave
like life as we know it.
The community, the ecology of the
extremophiles living in this river,
they don't need to eat
complex organic molecules
like our cells have to,
like human cells or animal cells,
they've got
far simpler requirements,
and all those cells need to munch
on are fundamental things
like iron and sulphur
dissolved in the water,
and they're reacting together
and use that chemical reaction
to power themselves,
and a by-product - a waste product,
if you like - of that living process
is the sulphuric acid and that's why
Rio Tinto is so phenomenally acidic.
So life can find ways to survive
even in conditions people thought
would mean instant death.
That raises hope
that similar microbes could exist
on other planets.
So scientists are waiting
with bated breath
to see what Curiosity will tell us
about the conditions
on ancient Mars.
They might not have been
all that different
to some of the places
extreme life survives on Earth.
But before Curiosity can begin
its scientific mission,
..it first has to touch down safely
on the Red Planet's surface.
With landing day now looming close,
the responsibility weighs heavily
on the shoulders
of lead engineer Joel Krajewski.
All engineers are aware, of course,
of the risks of a mission like this,
and the pressure of that,
or the stress of that awareness,
different people handle
in different ways.
I go surfing.
You spot a good wave...
..paddle hard,
feel the lift behind your feet,
dig a heel in...
..and the wave takes you
all the way in to shore.
But no matter how much
you've practised...
..nature can surprise you.
You can see a good wave...
..paddle hard for it...
..and - wham!
That's a wipe-out.
I would not want
to wipe out in space.
Back at NASA's
Jet Propulsion Laboratory...
..it's not just Joel
who is feeling the pressure.
Although Curiosity
is only weeks from arrival,
the team is working
harder than ever.
Any loose ends
that are going to be messy?
Like, you know, the eyes not closed,
any of that kind of stuff
that we're going to have to deal
with? The eyes are all closed.
With most of the testing
now complete,
it's no longer machine failure
that is worrying Joel.
It's the possibility of human error.
We have done all of the instrument
and engineering check-outs
on the vehicle,
so we know the vehicle survived
the launch experience well
and it's healthy.
Of course, what's not quite ready
is us - we, the team.
We have to operate this vehicle
through the landing event
and then in the science mission
after that,
and for that, of course,
we have to train ourselves.
RADIO CHATTER
With 80 days to go until landing,
the team are carrying out
their toughest test.
A complete rehearsal of
the Rover's landing, in real time.
The spacecraft is now reporting,
radio has reached entry interface
and things are nominal.
Although it's a simulation,
it feels just like the real thing.
This is the big day,
which is to say the big night.
We've gone through
five days of approach,
but now here, we have only
a few hours left until landing
and so it's kind of...
This is for the money!
As they simulate the Rover's
final approach to Mars,
the atmosphere
in the control room is good.
Even the scientists
have arrived to watch the show.
It's going really well.
We're just under 30 minutes until
we touch down on the surface of Mars.
Everything's looking good.
But Joel wants to give the team
a real test,
so this rehearsal
won't go perfectly.
Hidden in the wings,
a team of gremlin engineers
is making it appear as if the
spacecraft is encountering problems.
So we're going to learn,
all together now,
how well the whole team is able
to navigate through problems
and make good choices, precisely
in the state of extreme exhaustion.
You get caught up in it
because the screens look the same
as when we're looking at
the real spacecraft,
the people are sitting
in the same positions -
I'm in the chair I'm going to be
in - you're doing the night shift.
You're kind of tired
and kind of on edge
and so when you see, like,
monitors go red and everything,
for a second... (GASPS)
It's very compelling.
As the simulation
of the landing begins,
it's Adam Stezlner's turn
to practise guiding Curiosity
safely onto the surface of Mars.
I feel like a fisherman
who's caught a whale
and I just don't know...
Can I do this? Am I up for this?
The huge distance
between Earth and Mars
means that once the team
has sent the instruction to land,
there will be no going back.
The spacecraft has reached entry
interface and things are nominal.
Any message they send to Curiosity
takes 14 minutes to get there,
so for the final stages
the Rover will be on its own.
For them the landing will be like
the longest roller coaster ride
they've ever taken.
Stand by for parachute deploy.
Effectively they make their bet
and they say, "OK, go,"
and it's hands off
and the actual landing itself -
going through the atmosphere...
Confirming that we have
parachute deploy.
..jettisoning hardware...
Heat shield has been jettisoned.
..firing thrusters...
Powered flight has begun.
..that all has to happen
autonomously by the vehicle,
which is actually harder
for people, I think.
It's only a rehearsal,
but there is still a tense wait
as the Rover performs
the last of the landing manoeuvres.
Eventually,
Curiosity touches down safely.
APPLAUSE
The team did really well
and they kept their heads
under pressure
and we're still working
really well under pressure,
and so that's all I could ask.
The rest is in the hands
of the fates.
The team are now preparing
to go through this procedure
one final time.
In six days, we'll find out
if they can do it for real.
Subtitles by Red Bee Media Ltd
sophisticated space vehicles
ever built.
Curiosity is a billion-dollar rover.
In six days' time, it will attempt
to touch down on Mars.
Landing a big rover
is a tough business.
It means that everything
about the system gets bigger
and therefore harder.
This will be no ordinary landing.
It will be winched down by a crane
hovering in the Martian sky.
It's so ambitious, it's so
audacious, it's so unconventional.
Horizon has been behind the scenes
with NASA's team as they follow
their rover across
350 million miles of space.
When Curiosity comes over
the horizon,
this guy is already pointed
that direction and as she comes up,
then we're talking.
Curiosity's mission is to discover
if Mars could ever have
supported life.
But the Red Planet has become known
as the Bermuda Triangle of space.
Two-thirds of missions there
have ended in failure.
In just under a week,
the world will learn
if Curiosity can overcome the odds
and touch down on Mars.
SPEECH OVER RADIOS
It's 10pm at the Jet Propulsion
Laboratory in California.
OK, copy and we'll make that report
to the surface team
when they come onboard.
The team behind the Curiosity
mission are locked
in a crucial test at
the space flight control centre.
We're now about five and a half
minutes to entry.
They're practising for a landing
they know is the most audacious
ever attempted on another planet.
Three minutes to entry.
They've been rehearsing and testing
day and night for months,
running through each individual
step of the mission in
painstaking detail.
Confirming that we have
parachute deploy.
Brian Portock is the flight director
for the 350 million-mile
journey to Mars.
Ann Devereaux helped devise a way to
stay in touch with the rover.
Adam Stelzner will mastermind
the daredevil landing.
And leading this test is
Chief Engineer, Joel Krajewski.
The fate of this mission is central
to everybody's soul, really.
Most folks have worked on this for
three years, five years, eight years.
You don't get to do many
in a given career.
You only get to do a few
if you're lucky.
So the stakes for everybody are
as high as they can be.
This is just a rehearsal,
but on the 6th of August,
they'll be doing it for real,
hoping the Curiosity rover
will arrive safely at its
destination.
Mars, the Red Planet.
It's become known as
the Bermuda Triangle of space.
Since the launch of the first
rocket there in the 1960s,
two-thirds of all missions
have ended in disaster.
The mission logs make scary reading.
"Failed to launch."
"Missed the planet."
"Lost radio contact."
"Lost on arrival."
The team knows Curiosity might never
reach the surface of Mars.
It's Joel Krajewski's job to make
sure this mission is a success.
His day may begin like
many Californians...
but then he heads to
NASA's Jet Propulsion Laboratory.
Like anyone else,
I drive into work every morning
but every morning as I do so,
I pinch myself because
I get to work on a space mission
and that is, that is pretty cool.
For more than a decade,
Joel has been engineering rovers
to send to the Red Planet.
Before I got into working on rovers,
of course like anybody else
I thought it was going to be
a kind of a tricky business.
It sounds hard throwing things
up into space
and exploring other planets.
Once I got into it, I learned that
it's even harder than I thought.
This is the third rover that
Joel has worked on.
But even for a Mars veteran
like him, Curiosity
has been a huge challenge.
Curiosity is the most complex vehicle
we have sent to Mars.
Hundreds of people have worked on it
for more than eight years
and we're still working on it.
Different people understand
different aspects of it,
but nobody knows it all.
As the real Curiosity hurtles
through space,
its clone is hidden in a garage
at the Jet Propulsion Laboratory.
It runs on its very own
nuclear generator.
Its components can withstand forces
greater than those
exerted on a supersonic jet.
And its electronics are designed to
work at temperatures far lower
than the coldest places on Earth.
It's the most advanced moving
vehicle ever sent into space.
Today, Joel's team are testing
the wheels of Curiosity's twin.
They're low class.
Is that what we call them?
That's what we call them.
It's just one of hundreds of tests
the rover has been through
in the past nine months.
That's great.
The scientists want to land on
Mars and explore.
They want to explore where we land
and then also explore
kilometres away from where we land,
and that means we have to drive.
We'd like to be able to drive
over big rocks
so that we can drive close to
a straight line,
not too much meandering around, and
therefore we designed a big rover.
That makes it tricky.
The reason Curiosity is so big
and expensive
is because of the science it will be
conducting on Mars.
It will have to
drive across difficult terrain
while carrying a lab full
of equipment.
The scientists would
like an infinitely capable vehicle.
But in the real world, the machine
has to fit within a certain volume.
It has to fit within a certain mass.
We can only lift
so much mass off the Earth
and have it land safely on Mars.
The rover is five times as heavy as
any vehicle they've ever launched,
which makes landing
it on another planet
more difficult than anything
they've attempted before.
Landing a big rover
is a tough business.
The landing system is more complex,
parachutes are bigger,
everything gets much bigger
and therefore harder.
# There's a starman
waiting in the sky... #
NASA's engineers have never shied
away from tricky landings.
# There's a starman... #
During the Apollo
missions of the 1970s,
they weren't satisfied just to
put a man on the moon.
But landing a car on Mars is
an entirely different proposition.
Adam Stelzner has spent years
working out how to do it.
He will take control of the rover
as it begins to enter
the Martian atmosphere.
He won't be able to rely
upon the systems
that got the lunar rover down safely
onto the surface of the moon.
Mars is tough.
The moon, where we've landed lunar
modules on the moon before,
does not have any atmosphere
and it makes the process of getting
down to the surface kind of simple.
You take a rocket engine, you turn
it on and you slow yourself down
until you touch down on the surface.
Unlike the lunar rovers,
Curiosity will have to battle
an unpredictable atmosphere.
Historically, Mars has been evil.
You don't know what the weather's
going to be like, you don't know
whether the atmosphere's going
to be dense or diffuse.
Will it be a hot day and not
so dense, or a cold and dense day?
If it's cold and dense, you slow
down faster, you end up shorter.
If it's hot and low density,
you end up flying farther.
The dangers of this unpredictable
atmosphere are heightened
by the speed the spacecraft
has to travel at to get to Mars.
It will arrive at
13,000 miles per hour.
We have enough energy of motion
in the spacecraft that we could
vaporise the spacecraft
in the atmosphere of Mars
just by slamming into that
atmosphere and developing
so much friction that
the vehicle would burn up.
So it's a challenge.
The rover will be
tucked inside a spacecraft
when it reaches the dangerous
Martian atmosphere.
Its first line of defence will be
the world's biggest heat shield.
Next, the team have to stop it
from crashing head-on
into the Red Planet.
So they have designed the biggest
supersonic parachute ever made.
In NASA's giant wind tunnel near San
Francisco, they put it to the test.
'Five, four, three, two, one...'
The parachute must be deployed
at twice the speed of sound.
Good chute, good chute!
The tests confirmed the huge canopy
should survive the enormous forces
it will encounter as it's dragged
through the Martian atmosphere.
Finally, Curiosity's engineers
tested the most risky part
of the landing procedure...
I think we are ready to go.
..a bizarre hovering crane
that will have to lower the rover
down the final 20 metres
to the surface.
CHEERING
The sky crane took the engineers
years to perfect.
It has never been used to land
anything before.
But although all of Curiosity's
individual landing stages
passed their tests on Earth
before launch,
they have never been tested
all together.
The Red Planet's evil environment
will be the first place the whole
procedure is ever attempted.
MUSIC: "Pumped Up Kicks"
by Foster The People
Planning the journey was the first
challenge for Joel Krajewski's
engineering team.
Go, go, go, go, go!
Nice job!
APPLAUSE
As Flight Director, Joel's colleague
Brian Portock is, in effect,
the mission's quarterback.
CHEERING
# Robert's got a quick hand... #
It's Brian's job to aim and throw
the spacecraft across the solar
system to a moving receiver...
..Mars.
PLAYERS SHOUT
Everything's in motion in space.
Run in, run in!
Mars is moving round the sun and the
Earth is also moving round the sun,
and their motion relative
to each other is changing.
Go, go, go, go!
Similar to a receiver running out
for a pass is in motion...
Ball!
..and the quarterback needs to
stand back and throw a ball...
Really good shot!
..so that the receiver and the ball
meet at a point in space
and a time that's the correct one
so that they can catch it.
Oh, nice!
CHEERING
They need to figure out how far
the ball needs to travel depending on
where the receiver is.
Go, go, go! How fast the receiver's
running in that direction.
Most quarterbacks don't sit down
and calculate that on paper.
Set, go!
It's all done in their head
instinctively,
without thinking about it.
For spacecraft, we do it on paper,
or these days, on computers.
PLAYER SHOUTS
The other thing a quarterback does
is put spin on the ball.
Spiral so that the ball flies
in the correct trajectory.
So we also are spinning
our spacecraft...
so it maintains its attitude...
..and so that we can point the solar
rays back at the sun and communicate
back to the Earth.
And so, the actual rotation
of the ball
is similar to the rotation
of the spacecraft.
They make it sound simple,
but firing a spacecraft
across the solar system
involves some really complex
ballistic calculations.
The craft must escape the pull
of the Earth's gravity.
It must contend with solar winds
that could blow it off course....
cosmic radiation which can
disrupt radio contact...
..and the craft is constantly being
dragged from its course
by the gravitational pull
of other planets.
Just a tiny error could result in
Curiosity missing Mars altogether.
To get the distance scales
approximately similar,
the quarterback here is throwing
a pass 30 metres, 40 metres away.
Brian's target of Mars is hundreds
of millions of kilometres away.
It's similar to if this quarterback
here were throwing a football
to a receiver in, say, London,
and needing to hit his mark.
APPLAUSE
It'd be the wrong kind of football.
LAUGHS: Yeah!
In November 2011,
at Kennedy Space Centre,
the rover made its way to the
launch pad on an Atlas rocket.
For the mission team, the launch
is the moment of no return.
While the craft is on the ground,
final fixes can always be made.
But once it's in the air, a fault
could mean the end of the mission.
There's so much energy involved
with launching.
SPACECRAFT BLASTS
All the little piece parts
on the spacecraft
are designed to survive
that vibration and those forces.
Just the fact that it gets into space
and we start talking to it
for the first time
is an incredible achievement.
It's spacecraft separation.
APPLAUSE
It's the first big step
on the way to Mars.
But any damage caused by the launch
to Curiosity's components might not
be immediately obvious.
So, for the past eight months,
the engineers have needed to stay
in careful contact,
to check its course
and its vital signs.
'Re-transmit...
Six, three, eight...'
They need to be sure that they
receive every message sent back
by the rover...
and that every instruction they give
will be heard loud and clear.
MUSIC: "Sweet Child O' Mine"
by Guns N' Roses
To communicate with Curiosity,
the team have to rely on equipment
hidden deep in the Mojave desert.
Ann Devereaux helped engineer
the systems that allow the team
to stay in touch.
Now that the spacecraft is nearing
the end of its voyage,
she feels the distance between her
and her rover more than ever.
It's very much akin
to having a kid in college.
We raised her,
we taught her everything she knows,
we gave her all the gear that she
needs to investigate her new world,
but now she's gone.
And, you know, we gave her a calling
card. We told her to call often,
but we don't get to talk to her
all the time, and, you know,
we don't know what she does every
day until she's in contact with us.
# Whoa, whoa, whoa
Sweet child o' mine. #
Curiosity can call home using two
ultra-high-frequency radios.
But the distance between Mars
and Earth,
together with the rover's
limited power,
makes it difficult
to pick up the signal.
It's a problem anyone with
a car radio knows well.
RADIO INTERFERENCE WARPS MUSIC
We're about a hundred miles outside
of Los Angeles.
In the car,
I've got the radio going,
but my favourite radio station
is almost gone.
I'm not that far,
certainly compared to Mars,
and the radio station that I listen
to has a 90,000-watt transmitter,
and so you'd wonder why I can't
pick up the station here.
The problem is my little antenna
is just not capable of picking
up the signal at this distance,
no matter how powerful it seems
the transmitter back at home is.
MUSIC: "Spread Your Love"
by Black Rebel Motorcycle Club
In space, power is in short supply,
and Curiosity will need to use
almost all of its energy
to drag its near-ton weight
across the surface of Mars.
That means the rover's transmitters
have to get by with just a fraction
of the 90,000 watts used by
a radio station on Earth.
She only has a ten-watt transmitter,
and she's MUCH further away.
We're about 140 kilometres
from Los Angeles -
Curiosity is going to be 250 million
kilometres at Mars.
We need something bigger
for an antenna.
# Spread you love like a fever
# Spread your love like a fever
# Spread your love like a fever
# Spread your love like a fever. #
The DSS14 antenna
is the biggest dish
in NASA's Deep Space
Communications Network.
It's their switchboard for every
spacecraft in the solar system.
But all this interplanetary chatter
means that Ann can't just pick up
the phone to Curiosity
any time she likes.
There's a lot of spacecraft out
there, and they all want to talk
back home, too, right?
They all want to call home.
And so, we have to schedule time
at one of these antennas,
like here at DSS14,
and tell the people that we need to
talk to Curiosity and this is how
long we want to talk to her for,
and they point the antenna so when
Curiosity comes over the horizon,
this guy is already pointed in that
direction and as she comes up,
then we're talking.
But a queue for the phone is not
the only thing that could kill
the conversation between the rover
and the team back home.
Once it arrives at Mars,
the whole mass of the planet
will stand in the way.
Mars itself rotates
as the Earth rotates,
and so sometimes, even if we wanted
to talk to Curiosity, we couldn't.
Because we just have the whole
planet between us and Curiosity.
A Martian day lasts 24 hours
and 40 minutes.
For half of that time,
the rover will drop behind
the red planet's horizon,
out of view of Earth's antennas.
When Curiosity arrives,
night will be falling on Mars.
Midway through its perilous
landing procedure,
the team will lose direct contact
with the spacecraft.
But NASA can rely on help
from some previous Mars missions.
We have an ace in the hole.
In fact, we have two.
It's called Mars Reconnaissance
Orbiter and Mars Odyssey.
So, these are two orbiters
that we have around Mars already.
They're sitting there, they're
waiting for their sister to come.
As the Martian night obscures
the rover from Earth's view,
Odyssey will attempt to relay
its vital messages
back to the control room.
This is just one of hundreds
of risky procedures
that must go right
for Curiosity to land safely.
In designing the most complex
landing ever attempted in space,
the team have had to go out on
a limb, staking their reputations
on a system that has
never been used before.
It's so ambitious. It's so
audacious. It's so unconventional.
It doesn't feel like
there's a lot of shelter.
You can't say,
"Oh, I'm doing what they did before
"and it just didn't work out,
I didn't get lucky."
No, we're not doing what we did
before.
We're doing something completely
novel, hanging it way out there.
Um...
You feel exposed.
As chief architect of Curiosity's
landing sequence,
Adam Steltzner has gone through
each part of it
over and over in his head.
But for now,
it only exists in his imagination.
And in this NASA animation.
We show up at this
near six-kilometre-a-second speed.
We burn a hole in the sky of Mars
for about 100 kilometres long.
We start out
at six kilometres a second,
and we're still going
about a kilometre a second.
We're not slowing down very
much, because there's not enough
atmosphere to help us out.
So eventually we have to pop
a parachute.
That slows us down more.
But still not enough.
It takes us down to about
100 metres a second.
200 miles an hour, almost.
You don't want to hit the surface
of Mars like that.
So, about a couple of kilometres
from the surface,
we decide it's time to look
for the surface with our radar.
And once we've seen it,
we take this great leap of faith.
And cut ourselves free,
light our rockets and start
our descent to the surface.
We slow ourselves all the way down,
and then, 20 metres above
the surface,
we do this kind of crazy thing...
called the sky crane manoeuvre.
Zzz-zzz...
The average person on the street
thinks it's crazy.
Even the team that's working it,
sometimes we think it's crazy.
The strange part is,
it's actually the result
of reasoned engineering thought.
Six days from now,
the team hope Curiosity will execute
this unlikely manoeuvre.
Back on Earth,
they will be waiting for the message
they have all dreamed of...
..it's safely down.
The purpose behind all this
daredevil engineering
is to send the biggest payload
of scientific equipment
ever to leave Earth
to uncover the secrets of Mars.
It's the latest step
in mankind's love affair
with this curious red light
in the night sky.
Ever since Galileo
built his first telescope,
astronomers professional
and amateur alike
have peered through their lenses
at the red planet.
Oh, yes.
Do you see it?
I see it.
I see some bright colours.
You see some bright colours?
I think it's Mars.
You think it's Mars?
I think you might be right.
It's Mars, for goodness' sake - now
how could you not be interested?
It's just beautiful.
Mars has, you know, intrigued people
for so many years.
I think it's that red colour
that attracts people,
and it's just...
just the romance of it.
That's wonderful.
Curiosity's planetary scientist
Ashwin Vasavada
has shared this fascination
since he was a boy.
Looking at Mars through a telescope,
you can see some wonderful things.
You can see the planet,
you can see the polar caps come
and go with the seasons.
I love looking through telescopes,
but really, they're almost like
using a record player for someone
who grew up with the internet.
In 1976, we moved beyond
mere telescopes.
When the Viking space probe
beamed back the first-ever images
from the surface of Mars,
it inspired a whole generation
of space scientists.
This image is an image taken
by the Viking lander in 1976,
and it kind of is a special image
for me,
because I saw this image in a book
I was reading as a young kid.
And it's the first time
I really noticed that planets
were other worlds.
You could stand on a planet,
look out and see rocks
and you could walk off the horizon
of the image you're looking at,
and you wonder
what's across that hill.
It just blew me away, and maybe
it's the moment I became
a planetary scientist.
The Viking mission tapped into
the public's fascination with Mars.
It was inspired by one of the most
intriguing questions in science.
Are we alone?
It's about searching for life
in the universe,
it's about asking this profound
question of whether we're alone,
whether we're all that there is.
And the only way we can do that,
even in this technological age,
is just by stepping out
to our nearest neighbour planet,
the one next furthest out from the
sun, and asking the question there.
But really, it's going to tell us
this profound reality,
whether we're alone or we're not.
NASA's Viking mission
was hugely ambitious.
It was their first ever attempt
to land robotic probes
on the surface of Mars.
And it was going to search
for life itself.
It has an arm, so it can extend
out into the area around it
and pick up sand to bring back
to the other laboratories
which are on board the lander.
The Viking landers were equipped
with these state-of-the-art
biological laboratories
and they scooped up soil
and analysed it.
They tried to feed any microbes
that would be in the soil
and do very sophisticated
experiments to detect life.
CHEERING
The delight of landing safely
and receiving these
extraordinary pictures
was followed by what seemed to be
an incredible discovery.
Initial observations suggested that
they had detected microbial life
in the Martian soil.
But as the euphoria subsided
and the scientific data was
analysed, a new realisation dawned.
Viking had in fact failed
to find life on Mars.
And the results were either
negative or just ambiguous
and it made us realise that
it's not going to be this easy.
Since the 1970s, other missions
have told us much more about Mars.
Successful Rovers and orbiters
have produced detailed maps
of the red planet's surface
and breakdowns of its atmosphere.
They have revealed just how hard
it would be for life to survive
in the planet's extreme environment.
The surface of Mars today
is a very harsh place to life.
There's a lot of things
that are hazards to life.
Now we're interested in knowing
whether those same hazards
were there in the past
and maybe early Mars as opposed
to present Mars was the place
to look for life.
Today, Mars is
an inhospitable desert.
Its thin atmosphere leaves
its surface exposed
to lethal solar
and cosmic radiation.
Average temperatures of minus 55
degrees Celsius
would make it very hard for life
as we know it to survive.
That's why Curiosity is not
expecting to find life here and now.
Instead, it will try to discover
if life could have survived there
millions of years ago.
Which means the Rover not only
has to travel all the way to Mars,
it has to travel back in time.
This desert, 200 miles
outside Los Angeles
has become a second home
for the Curiosity team.
It's an ideal place not
just to test the Rover,
but also to design
the mission's science.
Chief scientist John Grotzinger
is in charge of the experiments
that will enable the Rover
to see into the past.
Not by looking for bones or fossils,
but by trying to find
elements crucial for life.
Simple things,
like liquid water.
What we're going to do
is an acid test.
Take a few drops, put it on the rock
and see if it fizzes.
And yes, cool, it fizzes.
And what that tells us is that
this work is made out of
a mineral called carbonate.
And carbonates on Earth
form in lots of water,
and that tells us that this dry
desert that we are in here today,
600 million years ago,
there was an ocean.
It was liquid water
in ancient lakes and seas
that allowed life to take hold.
So Curiosity's scientists
have carefully chosen
a Martian landing site
similar to this spot
in the Mojave Desert.
Curiosity will hunt for the same
evidence of a wetter past
in the Gale Crater on Mars.
Here's Gale Crater, with Mount Sharp
majestically rising above the plains.
Mount Sharp is a Martian mountain,
rising 18,000 feet above the centre
of the massive Gale Crater.
The scientists believe their Rover
could find carbonates here, proving
this Martian crater was also filled
with water in its ancient past.
But that's not the only similarity
that Mount Sharp has
with the mountains
here in the Mojave Desert.
In both places, the team can use the
rock itself to travel back in time
to any moment
in the geological past.
The mountains are formed of layers,
built up gradually over millennia.
Testing each one will reveal
what the environment
was like there
at the particular moment in time
it was laid down.
What we see here is
a stack of layers that tell us
about the early environmental
history of the Earth,
representing
hundreds of millions of years.
They read like a book of
Earth history and they tell us about
different chapters in the evolution
of early environments and life.
And the cool thing about going
to Mount Sharp at Gale Crater
is going to be there,
we'll have a different book
about the early environmental history
of Mars that will tell us
something equally interesting, and we
don't know what it's going to be yet.
The team believe the place
they've chosen to land is
the perfect spot
to look back in time.
They want to know if Mars
could have supported life
at any point in its history.
So that Curiosity can discover
all the information
the scientists need,
the engineers have designed it
to work just like
a human exploration team would
back here on our own planet.
What Curiosity can do
as we begin to explore Gale,
is pretty much what
a geologist would do on Earth,
but it's also bringing along
a chemistry lab.
The official name of the mission
is Mars Science Laboratory.
And with good reason.
We have three different
camera systems.
We have another instrument that
involves a laser that gives us
the ability to zap out
and understand
the composition
of the environment around us.
We've got instruments that can ping
things down in the subsurface
and tell us if there's water
down there.
And then we've got other instruments
that can actually tell us
about the laboratory conditions,
like what we would do on Earth.
It's this chemistry lab,
right in the belly of the Rover,
that makes the mission
really special.
What Curiosity can do,
which has never been done before
on a Rover mission,
is to actually drill a hole
in the rock,
take the powder and put it
into the chemistry laboratory
which is inside the Rover.
And that I'm really excited about,
because it takes us
to a whole other level
with science analysis on Mars.
This is a clone of
an essential piece of Curiosity's
mobile chemistry kit.
It was constructed here
at the Goddard Space Laboratory
by planetary scientist Paul Mahaffy
and his team.
This equipment, known as SAM,
can reveal the chemicals
present in the Martian rock.
But for it to work,
SAM needs to be fed the right sort
of rock samples, correctly prepared.
So Curiosity will first have to use
all the other tools it has
at its disposal.
The very first tools are
the very high resolution cameras
on the mast of Curiosity.
And then, when we get even closer
to a sample
that we might see in the distance
and then approach,
we'll start using other tools.
For example, on the mast is
an experiment
called ChemCam.
ChemCam will point at a rock
and fire a laser.
And then look at the emissions
that come off from that rock,
and that's really important
because it can tell the differences
between different types of rocks.
So if we come across a rock
that looks substantially different
from rocks we've looked at before,
then we might want to approach
those samples,
put out the arm,
and start interrogating that rock
or that outcrop
with instruments that are on the arm.
An element analyser
and a very nice microscope,
and if we examine the outcrop
or the rock with those tools
and decide it's worth
even further exploration,
then what we do is
we sample the rock.
We drill into the rock, we create
some powder with the sampling system
and then we deliver
that powder into SAM.
The chemical analysis
of this powdered rock
is one of the most important tests
in the mission.
That's why the team are still
running tests on SAM's twin
back here on earth.
We've put a bit of powdered rock
into the oven of SAM,
and we slowly heat it up
from ambient temperature
to very hot temperature,
about 1,000 degrees centigrade.
And as the sample is heated up,
at different temperatures it releases
different simple gases or complex
gases, and that helps us determine
what the mineralogy, what the
mineral composition of the rock is.
SAM can look for the chemical
signatures of water
and it can also detect
organic compounds -
the building blocks of life.
Our very first job on getting
to Mars will be to understand
if there are organic compounds
that we can even detect.
Mars is a very harsh environment.
Ultraviolet radiation penetrates
right down to the surface
because there is less of
an atmosphere than on Earth.
The same is true for very energetic
cosmic radiation
that pounds in and really has
the potential to destroy
fragile compounds that are
very close to the surface.
So that's a very first-order
question -
are there organic compounds on Mars?
Can we detect them with SAM?
And if there are,
then the fun really starts.
The discovery of organic compounds
on Mars
would cause huge excitement
right across the globe.
Together with liquid water, they are
regarded as essentials for life.
Curiosity's other tests will reveal
whether the ancient
Martian environment
could have allowed life itself
to form from these building blocks.
Even in the best-case scenario,
the environment on early Mars would
still have been pretty hostile.
So to understand if extraterrestrial
life could have formed,
astrobiologists like Lewis Dartnell
need to find out
the most extreme conditions
in which life could still survive.
They do it by looking for the limits
of life here on Earth.
Searching out harsh,
dangerous environments,
places where we used to think
life could never exist.
A lot of what we're trying to do
is understand the limits
of terrestrial organisms.
What's the survival envelope
of Earth life, so places
that are very hot and acidic
or are very cold and dry,
like Antarctica,
or some very high-pressure,
very high temperature places,
like the black smokers and the
hydrothermal vents on the sea floor.
Because it's by understanding
life in these most hostile
environments on Earth
that we understand a lot about
the possibility of there being life
on other worlds,
and in similar environments.
This decaying train line is one of
these hostile environments on Earth.
It's a strange, alien landscape,
cut through by one of the world's
most extraordinary rivers.
Now, that's...
That is blood, blood-red.
That's incredible.
The Rio Tinto is
100 kilometres long,
running from the mountains of
Andalusia to the Gulf of Cadiz.
It is been used by NASA
to test life-detection equipment
for Mars missions.
Rio Tinto is one of those places that
you read about time and time again.
It's commonly used as an example of a
Mars-like environment here on Earth.
I've seen loads of photos in journal
papers and books, textbooks,
but it's only when you come here
and see with your own eyes
that it just jumps out at you.
That is... That is an alien colour
for a river, that is, blood red.
To understand what Mars might have
been like millions of years ago,
astrobiologist first try
to understand these desolate
places on earth.
Actually, the reason that the waters
here in Rio Tinto are blood red
is because the substance
is the same.
The oxidised iron in our blood
is the same stuff as in that river
turning it that grotesque,
off colour.
It's absolutely amazing.
It had always been thought
that this strange red colour
was a result of pollution,
that the water had been tainted
by iron and other metals
washed downstream from the mines
that have existed here
since Roman times.
Well, I can't see anything
obviously alive,
and there's clearly
no fish swimming around in here.
There are no visible signs of life.
And the Rio Tinto's waters
hold another secret,
which made people think
there was no hope
of even the tiniest life forms
ever existing here.
So, I've got a PH meter here,
and I'm going to test the acidity
of the water in the Rio Tinto
at this place here.
Now, a normal river,
a healthy river, would be PH7 -
that's neutral.
And, obviously, the lower the
number, the greater the acidity is.
So I'm going to take a sample...
here...
..dunk in the PH probe and we see
that it's dropped below 3 already,
2.7 and it's levelling off
at about 2.65, so that's acidic.
That's about 100,000 times
more acidic than a normal river.
And that's almost as acidic
as stomach acid.
That is one acidic river.
If liquid water
ever existed on Mars,
it might well have been
a metallic acid river like this.
It seems unlikely to think that life
could have emerged
in such a hostile environment,
but scientists have discovered
this blood-red river
is actually teeming
with microscopic bacteria.
This is a microscope photograph
of the river water
and you can see these thin,
hair-like threads
down the microscope, and these are
the microbial filaments themselves,
these are the cells,
these are the life in this water.
These extraordinary bacteria
are not just tolerating
the strange river conditions -
they're actually creating them.
They simply don't behave
like life as we know it.
The community, the ecology of the
extremophiles living in this river,
they don't need to eat
complex organic molecules
like our cells have to,
like human cells or animal cells,
they've got
far simpler requirements,
and all those cells need to munch
on are fundamental things
like iron and sulphur
dissolved in the water,
and they're reacting together
and use that chemical reaction
to power themselves,
and a by-product - a waste product,
if you like - of that living process
is the sulphuric acid and that's why
Rio Tinto is so phenomenally acidic.
So life can find ways to survive
even in conditions people thought
would mean instant death.
That raises hope
that similar microbes could exist
on other planets.
So scientists are waiting
with bated breath
to see what Curiosity will tell us
about the conditions
on ancient Mars.
They might not have been
all that different
to some of the places
extreme life survives on Earth.
But before Curiosity can begin
its scientific mission,
..it first has to touch down safely
on the Red Planet's surface.
With landing day now looming close,
the responsibility weighs heavily
on the shoulders
of lead engineer Joel Krajewski.
All engineers are aware, of course,
of the risks of a mission like this,
and the pressure of that,
or the stress of that awareness,
different people handle
in different ways.
I go surfing.
You spot a good wave...
..paddle hard,
feel the lift behind your feet,
dig a heel in...
..and the wave takes you
all the way in to shore.
But no matter how much
you've practised...
..nature can surprise you.
You can see a good wave...
..paddle hard for it...
..and - wham!
That's a wipe-out.
I would not want
to wipe out in space.
Back at NASA's
Jet Propulsion Laboratory...
..it's not just Joel
who is feeling the pressure.
Although Curiosity
is only weeks from arrival,
the team is working
harder than ever.
Any loose ends
that are going to be messy?
Like, you know, the eyes not closed,
any of that kind of stuff
that we're going to have to deal
with? The eyes are all closed.
With most of the testing
now complete,
it's no longer machine failure
that is worrying Joel.
It's the possibility of human error.
We have done all of the instrument
and engineering check-outs
on the vehicle,
so we know the vehicle survived
the launch experience well
and it's healthy.
Of course, what's not quite ready
is us - we, the team.
We have to operate this vehicle
through the landing event
and then in the science mission
after that,
and for that, of course,
we have to train ourselves.
RADIO CHATTER
With 80 days to go until landing,
the team are carrying out
their toughest test.
A complete rehearsal of
the Rover's landing, in real time.
The spacecraft is now reporting,
radio has reached entry interface
and things are nominal.
Although it's a simulation,
it feels just like the real thing.
This is the big day,
which is to say the big night.
We've gone through
five days of approach,
but now here, we have only
a few hours left until landing
and so it's kind of...
This is for the money!
As they simulate the Rover's
final approach to Mars,
the atmosphere
in the control room is good.
Even the scientists
have arrived to watch the show.
It's going really well.
We're just under 30 minutes until
we touch down on the surface of Mars.
Everything's looking good.
But Joel wants to give the team
a real test,
so this rehearsal
won't go perfectly.
Hidden in the wings,
a team of gremlin engineers
is making it appear as if the
spacecraft is encountering problems.
So we're going to learn,
all together now,
how well the whole team is able
to navigate through problems
and make good choices, precisely
in the state of extreme exhaustion.
You get caught up in it
because the screens look the same
as when we're looking at
the real spacecraft,
the people are sitting
in the same positions -
I'm in the chair I'm going to be
in - you're doing the night shift.
You're kind of tired
and kind of on edge
and so when you see, like,
monitors go red and everything,
for a second... (GASPS)
It's very compelling.
As the simulation
of the landing begins,
it's Adam Stezlner's turn
to practise guiding Curiosity
safely onto the surface of Mars.
I feel like a fisherman
who's caught a whale
and I just don't know...
Can I do this? Am I up for this?
The huge distance
between Earth and Mars
means that once the team
has sent the instruction to land,
there will be no going back.
The spacecraft has reached entry
interface and things are nominal.
Any message they send to Curiosity
takes 14 minutes to get there,
so for the final stages
the Rover will be on its own.
For them the landing will be like
the longest roller coaster ride
they've ever taken.
Stand by for parachute deploy.
Effectively they make their bet
and they say, "OK, go,"
and it's hands off
and the actual landing itself -
going through the atmosphere...
Confirming that we have
parachute deploy.
..jettisoning hardware...
Heat shield has been jettisoned.
..firing thrusters...
Powered flight has begun.
..that all has to happen
autonomously by the vehicle,
which is actually harder
for people, I think.
It's only a rehearsal,
but there is still a tense wait
as the Rover performs
the last of the landing manoeuvres.
Eventually,
Curiosity touches down safely.
APPLAUSE
The team did really well
and they kept their heads
under pressure
and we're still working
really well under pressure,
and so that's all I could ask.
The rest is in the hands
of the fates.
The team are now preparing
to go through this procedure
one final time.
In six days, we'll find out
if they can do it for real.
Subtitles by Red Bee Media Ltd