Original subtitles

- Mars.

The god of war

and the source of man's science fictional demise.

It has fired our imagination for thousands of years.

We know the dry, barren planet was once flowing

with vast reservoirs of water,

the sky thick and filled with clouds,

and the tantalizing possibility of life.

It is the only other place in our solar system

that man might one day call home.

(exhilarating music)

We Earthlings have fired numerous probes and satellites

towards the red planet, an invasion of sorts,

not for conquest but for knowledge.

What happened to Mars?

Is there or has there ever been life on the planet?

- A fundamental question that needs to be answered,

is life as we know it on Earth,

even the simplest type of microbial life, unique?

If we were to go to Mars and we were to find evidence

of early microbial life or maybe even present life

that somehow survived in the near surface,

would it be the same as the early life

that developed on Earth?

That's a very fundamental question.

Does life emerge generally in planets

where the conditions for life are favorable

if we find out that they were favorable on Mars

or might life take its own unique path

in different environments and turn out differently?

(mellow music)

- We have bombarded Mars with satellites and landers,

but there have been more failures than successes.

The Soviets established two Mars orbiters

while NASA landed two Viking landers

carrying complex analytical laboratories

and search for signs of microbial life.

Their findings were inconclusive.

Further missions to Mars still had a high mortality rate,

but the successes were outstanding,

with robotic probes operating for years

beyond their initial missions.

In fact, Mars is a planet occupied solely

by robots on the surface

and satellites peering down from above.

All these instruments perform admirably

in their specified fields of endeavor,

giving us a much clearer picture of the planet

and its history.

The science was following the water,

what happened and where it is now.

- Thanks to the specific instrumentation

on board the mission, we are able to tell us

what kind of ice did we find.

And the result is that there is a mix

of CO2 ice, or carbon dioxide ice,

and water ice.

And it's very important to characterize it,

especially for the water ice, or frozen water,

because one of the main objective

of any mission to Mars is to trace the water

on Mars in every form.

Liquid, if possible, solid, water vapor.

So it's very important to study the ice

because it's one of reservoirs of water on the planet.

- The science was conclusive.

There was water on Mars.

There were ancient lakes and rivers, even an ocean.

We needed to learn more.

With the advancement of analytical technology,

computer power, and robotics,

a new rover was constructed.

Big, complex, and heavy, it required a new way

to land on Mars safely.

Engineers came up with a system

that couldn't be fully tested here on Earth.

It required a lot of things to happen correctly,

on time, and in order.

This was the sky crane

and the rover, Curiosity,

was the first to try it out.

A controlled reentry with heat shield,

aerobraking with a parachute, all pretty standard.

Then a rocket-powered sky crane drops from the aeroshell

and gently descends toward the surface,

spooling out the rover below on cables.

The rover touches down, cuts the cables,

and release the sky crane to fly off and crash harmlessly.

The Curiosity rover has been an astounding success,

traversing the terrain for over 10 years,

taking samples, drilling, and studying rock formations,

zapping samples with a powerful laser,

and photographing its progress.

- Now, in the belly of that rover

is an instrument called SAM.

It's an instrument suite that has

a couple different instruments in it that allow us

to look at different types of gases.

It helps us understand the chemical composition

of the atmosphere and of minerals that might be found

in the rocks and the soils on the surface.

In particular, it helps us identify organic molecules

that might be present.

- So, the sort of evidence we're looking for,

sort of signatures of past life

that we would be looking for

would be signature of microbial life.

So, not realistically looking for dinosaur bones

and that kind of thing.

If life ever existed on Mars,

we expect it to have been microbial, microorganisms.

(eerie futuristic music)

- Orbiters including Mars Odyssey and Mars Express

have been hunting down life as well, from orbit.

- After 10 years of mission,

we have achieve a global view of Mars

and then we know what every location on the surface,

if you find some special minerals or not.

So we have really the global view

that tell us the history of Mars.

Mars Express has, for the first time,

detected methane.

And also it comes from pressure in the atmosphere,

vary from the place to another,

from a season to another.

And this discovery, it's been very debated

in the scientific community

because, in fact, methane should not be there

because it's being destroyed in the atmosphere

by the ultraviolet radiation.

So if methane is there, there must be a source

of methane and for the time being,

the origin of this source is largely unknown.

- However, with Curiosity prowling around Gale Crater,

it too detected seasonal methane.

- Now, methane has been found previously

in the Martian atmosphere by both Earth-based telescopes

and space-born orbiters,

but this is the first time that we've actually seen

a sharp increase and decrease in the abundance of methane

in the atmosphere in Gale Crater.

But what this really means is that present day Mars

is an active environment.

- The big question is what is the origin of this methane

now being released?

The two principles areas are first,

by analogy with the Earth,

it could be released unproduced initially,

primarily by biology.

This would be microbial activity

acting on certain chemicals below the surface

and then producing methane as a byproduct.

But of course we can't stay with certitude

that it is biologically produced.

And so we also consider geochemical mechanisms

in which carbon dioxide is actually combining

with water and producing methane

under very high temperatures and pressures.

And that methane can then be released

in the atmosphere separately.

- Now, at this point we don't have enough evidence

to tell us whether or not the organics refining

are biological or nonbiological in origin.

There are several viable nonbiological explanations,

including this organic material could've come down

from space, from meteorites or comets,

or organics can be formed by geological reactions

in the rock itself.

Now what's exciting about this discovery

is it gives us new hope in the search

for chemical evidence of life.

We found the organic material.

Now the next step is trying to figure out

what its origin is.

(engine revving) - Main engine start.

Ignition and lift off

of the Atlas V with MAVEN,

looking for clues about the evolution of Mars

through its atmosphere.

(dramatic music)

- The latest NASA orbiter mission is MAVEN.

Launched in November 2013, it made orbit 10 months later.

(relaxing music)

- MAVEN is the Mars Atmosphere

and Volatile Evolution Mission.

Our goal is to study the role that lost to space

has played in the history of the atmosphere.

Where did the water go?

Where did the CO2 go from the early planet?

These are important questions to understand

how Mars went from an early warm, wet environment

to the cold, dry environment we see today.

- There's evidence of water flowing on Mars

at one point in time, perhaps even oceans on Mars.

And what happened that it's so barren at this point in time?

And a key part of that is the atmosphere

and it's a much thinner atmosphere than what scientists

believe it was at one point in time,

so the stripping away of that upper atmosphere,

that's what MAVEN is going after,

the climate change at Mars.

- One of these processes is called sputtering,

where atoms are knocked away from the atmosphere

due to impacts from energetic particles.

The sun constantly emits high energy photons.

When these enter a planet's atmosphere

it can crash into a molecule,

knocking loose an electron and turning it into an ion.

When this happens in the presence of a magnetic field,

the ions are captured and spin around the field.

Conveniently, the sun generates a giant magnetic field

that is carried by the solar wind.

As the magnetic field sweeps past the planet,

these ions are carried away.

Depending on where they form,

other ions will not be carried away

but will hit the top of the atmosphere.

These ions crash into other molecules

and fling atoms everywhere.

Some of these atoms can be knocked or sputtered into space

causing atmospheric loss.

As this process continues over billions of years,

Mars' atmosphere has disappeared

and along with it, the water.

How much water has Mars lost this way?

- We use the world's three majors telescopes

for infrared astronomy.

From the ground we could actually take a snapshot

of the whole hemisphere of the planet on a single night.

- Water naturally carries a heavy isotope

of hydrogen deuterium, which remains trapped

in the water cycle while normal hydrogen is lost to space.

Detecting the amount of deuterium enrichment

tells us how much water has been lost.

- Now we know that Mars' water is much more enriched

than terrestrial ocean water

in the heavy form of water, the deuterated form.

Immediately that permits us to estimate the amount of water

Mars has lost since it was young.

- So in the ancient past, when you have some indications

that water was flowing on the surface,

but how much water was there?

Talking about oceans, I'm talking about small rivers,

little rain.

So these definitions of how much water was on the planet,

it was very undefined.

- A major question has been how much water did Mars

actually have when it was young

and how did it lose that water?

- The findings indicate that only 13% of an ancient ocean

remains on the planet today,

now stored in the polar ice caps.

87% of this ocean has been lost to space.

This means that early Mars would have looked much different

than it does today, with a significant portion

of its surface covered by water.

- So the really interesting question is

could it form a sea or an ocean?

And indeed, it would.

In the northern plains, which is a relatively flat region,

but depressed from the rest of the planet,

it would form an ocean that was approximately

20% of the planet's surface area.

And so that is a respectable ocean.

- This ocean had a maximum depth of around 5,000 feet

or around one mile deep.

It's deep, not as deep as the deepest points of our oceans,

but comparable to average depth of the Mediterranean Sea.

- By combining Martian topography with a new estimate

for water loss, the researchers were able to simulate

Mars's ancient ocean and its escape to space.

As Mars lost its atmosphere over billions of years,

it lost the pressure and heat needed to keep water liquid,

causing the ocean to shrink and recede northward.

The remaining water eventually condensed

and froze over the north and south poles,

giving Mars the ice caps that we see today.

- We now know that Mars was wet

for a much longer time than we thought before.

Curiosity shows it was wet for 1.5 billion years,

already much longer than the period of time needed

for life to develop on Earth.

And now we see that Mars must've been wet

for a period even longer.

- It's fascinating that we can learn so much

about 4.5 billion years ago with measurement taken right now

and ultimately we can conclude this idea

of a ocean covering 20% of the planet,

which opens the idea of habitability

and the evolution of life on the planet.

- Building on this knowledge,

scientists are developing the next series of robotic probes

to be sent to Mars in the coming years.

This time, NASA is building on its successes,

utilizing hardware and systems that they know will work.

- We've been to Mars before

with the JPL, Lockheed Martin team.

We've been to the surface of Mars before successfully

with Phoenix.

We know how to operate the arm.

The surface operations are much, much simpler than Phoenix

and we're putting two instruments on the surface

and then we're leaving them there

with no ground-in-the-loop interaction.

Repetitive weekly up link, down link sessions.

We're just made to do this mission.

- The InSight mission is a geophysical mission to Mars.

It's gonna go to Mars and take its vital signs.

It's gonna take its heartbeat,

the seismic activity of the planet.

- So we're gonna be doing that using a seismometer,

a very high precision seismometer.

Using techniques that have been well-developed on Earth

to get the understanding of the crust, mantle, and core,

and sort of the relationship between those.

- Gonna take its temperature by measuring

the thermal gradient of the surface,

which tells how much heat is coming out.

And we also have a heat flow probe called HP Cubed

and what that does is it's gonna basically take

the temperature of Mars and from that it'll be able

to understand what the thermal flex is

over the course of a full Martian year.

- And it's gonna sort of measure its reflexes

by looking at how the rotation wobbles

with the tiled effects of the sun.

- Our final experiment is called RISE

and that's going to be looking at the,

basically the wobble of Mars to help understand

what the core size may be in composition.

- The European Space Agency is also well along

with ExoMars, a rover with advanced drilling capability

due to be launched by 2018.

Its principle goal, to drill down deep

in search of microorganisms.

(uplifting music)

- What is new with ExoMars, with the rover in particular,

is what we call the mobility.

Mobility, not only horizontal, but also vertical.

This is a particular thing that we have

on board ExoMars mission, so we will be able to sample

material from below the surface

that is quite important to understand

if there is any sign of a past life activity on Mars.

- We will be looking, for the first time,

in the third dimension,

the third dimension being depth.

And we think that is where we have the highest chance

of making an interesting discovery

regarding the presence of organic molecules in Mars.

- It's a whole planet out there

with a complicated history.

It's that history is a story that's stored in the rocks

and our job is to figure out that story

and what that story of that planet

tells us about this planet that we live on.

- So where Curiosity takes rocks and grinds them up

into powder and looks at their bulk constituents,

what this mission would need to do is be able to look

in a microscopic level and examine the rocks

for these very tiny and detailed messages

that they would be sending to us

about the past life that could've lived there.

- This that I'm holding up here

is a classic biosignature from the Earth,

it's a fossil.

We're not actually expecting to see a fossil

of shells or other components,

but what we want to be able to see are,

with this instrumentation,

are the fine-scale layering that one might see in a rock,

in which we can see dark and light-toned layers.

And those dark and light tone layers are telling a story.

(exhilarating music)

- When will NASA send astronauts to Mars?

- Five, four, three,

two, one.

And lift off at dawn.

The dawn of Orion

and a new era of American space exploration.

- The first test flight

of the Orion crew capsule is complete,

the hardware and systems are ready for mass production.

The components, the engineering, the manufacturing,

are all underway with NASA looking back

to what worked in the past

and utilizing it for the future.

- Fire.

- The solid rocket booster technology

straight from the space shuttle

has been extended and tested.

NASA's new Space Launch System, or SLS,

is coming closer to fruition,

reusing the space shuttle's main engines

as the new system's work horses,

saving billions of dollars

and years in research and development.

(suspenseful music)

The Europeans are teaming up with NASA

to provide the service model for Orion,

allowing for long duration, deep space flights.

Autonomous Martian landing systems are well advanced

and being tested.

Software and hardware are fully integrated

for both manned and unmanned Martian landings

and when they get there.

- Desert RAT stands for

Desert Research and Technology studies.

This is a group of engineers and scientists.

- We're looking to test out new concepts,

procedures, equipment, like rover concepts,

to see how they work in the field environment.

- So the team tests these technologies

to make sure that in future human space flight missions

we'll be able to do science as best as we can.

That's something that NASA's never done,

two human rovers at the same time.

So we're really trying to develop

how do you use these assets at the same time?

And interesting things that you might not think about

are your communications.

So you potentially have four astronauts talking

all at the same time to Mission Control

or science communication backroom.

- It's just like planning a real mission, say

like you kind of think about Apollo missions (mumbles).

You had the astronauts on the moon

and you had people, Mission Control,

but there was a science backroom you didn't hear about

but the astronauts were getting information from them.

- Arizona has a very good climate

for these types of analog studies.

You have pretty much open plains and you have a lot

of geological features that are analogous

to places on the moon and on Mars.

(relaxing upbeat music)

- Long-term space voyages are being replicated on the ground

and in orbit with the ISS.

Surface habitats, power systems,

food and oxygen supply manufacturing,

are also on the drawing board.

- The human flight component would like to see

an experiment where resources on the surfaces of Mars

from the rocks or the atmosphere could be used

to generate fuel or other parts

that would enable future exploration

in cutting the tie, so to speak, to Earth.

So you wouldn't necessarily have to bring

everything with you.

You can actually manufacture it on the planet

and that's a really exciting additional component

that we've been exploring and analyzing

in this work.

- NASA isn't the only one with its eye on this prize.

ESA and now the Indian Space Research Organization

have a spacecraft orbiting Mars

and they did it on their first attempt.

Private enterprise is hard at work as well.

Mars 500, Mars One, The Mars Society,

Mars Foundation, and the Mars Initiative, to name a few.

And they have volunteers lining up already

for a one-way trip to Mars.

It is inevitable that we will set foot on Mars

in the very near future.

We will stay and learn her secrets.

Perhaps in the future

we will be able to alter the atmospheric density

through terraforming and return Mars

to the world that it once was,

awash with oceans and rivers, clouds and rain.

Maybe some of us could call it home.

(relaxing nature music)