All language subtitles for How.the.Universe.Works.Series.8.Part.2.NASAs.Journey.to.Mars.1080p.HDTV.x264.AAC.MVGroup.org.eng

Narrator:
Nasa has set its sights on mars.

Its goal is to send humans
to the red planet

in the next 20 years.

Looking up at mars in the sky,

I really do feel like
I'm looking at a place

that someday there will
be people walking around on it.

It feels so much like earth
in so many ways,

and it's a place that really
captures my imagination

as a result.

Oluseyi: It's the most
earthlike environment

we see in our solar system.

So we're not going
to leave it alone.

We're going to try to do this.

Narrator: But conquering
our planetary neighbor

is a tougher challenge
than we ever thought possible.

It's an isolated environment

where a million things
can go wrong,

where there's absolutely
no hope of rescue.

Stricker:
There are so many hurdles
to overcome

for human exploration of mars,
and it makes it quite difficult.

Sure, we can get there, but are
we going to be in one piece?

Sometimes it feels like mars
is designed to keep us away.

Narrator: Are we doomed to fail
in this endeavor?

-- Captions by vitac --
www.Vitac.Com

captions paid for by
discovery communications

♪

the red planet --
earth's neighbor

and the destination of nasa's
most ambitious mission to date.

But this expedition
will be harder

than we ever thought possible.

It hurts to think
of how hard it is.

It's the farthest a human being
has ever been from the earth.

We got to take
every precaution

narrator: As nasa's astronauts
arrive at mars,

they'll face a huge obstacle.

Landing on the planet
is a daunting task.

In the past, mars hasn't always
rolled out the welcome mat.

Lanza: Mars is kind of like
a graveyard for spacecraft.

It's actually really hard
to send something from earth

and land it on mars.

Narrator: This is how
the european space agency

hoped its $250 million
schiaparelli lander

would touch down in 2016...

...But the lander's systems
got it wrong.

The parachute detached early,
sending the craft into free fall

for 33 seconds.

Schiaparelli smashed
into the surface

at 335 miles an hour,

leaving a deep, black scar
on the martian landscape.

Thaller: It turns out that mars
is actually

a particularly difficult planet
to land on.

Even humanity's most
brilliant engineers,

we've got about
a 50% success rate

when it comes
to landing on mars.

Narrator:
The red planet is littered
with dead spacecraft

that didn't stick the landing.

And for nasa's first
crewed descent to mars,

the space agency must learn
from these mistakes.

But as the crew hurdles
toward the surface

they're battling
the same problem

as all the landers
that failed before.

The martian atmosphere

is 100 times thinner
than earth's

so it can't provide
the drag needed

to slow a spacecraft down.

So it's not like the earth,
where you can have

these big, giant parachutes

that gently glide you down
to the surface.

You can use some of the air,
but it's hard.

Narrator: The red planet's
thin atmosphere

is a problem that's been
billions of years in the making.

Stricker: Mars doesn't have
a large atmosphere

because it's constantly
being peeled away

due to the lack of protection
of a magnetic field.

Narrator: The solar wind
can strip away an atmosphere.

On earth, a liquid metal core
creates a magnetic field

which shields the planet and
helps maintain the atmosphere.

Mars is different.

4.5 billion years ago,

mars and earth formed from dust
and gas in space.

Mars forms where
building materials were scarce.

Its growth was stunted.

So mars is much smaller
than the earth.

It's a factor of 10 smaller
than the earth,

and that factor of 10 in mass
is important.

All of that extra mass
allows the inside of the earth

to stay warm and to have a core
that's rotating,

which generates
a magnetic field.

Narrator: 4 billion years ago,
the churning heart of mars

started to cool
and solidify.

With no hot core, there's no
magnetic field being generated.

All of the high-velocity charged
particles coming from the sun

pick away at the atmosphere
and slowly tear it away.

We know it's losing atmosphere
every second

due to the solar wind.

So, you know,
bye-bye atmosphere.

♪

narrator: With little martian
atmosphere to work with,

nasa had to be creative
to get its crewless landers

to the martian surface.

♪

in 2012,
the revolutionary sky crane

landed the curiosity rover using
parachutes and retro rockets.

Previous missions have used
both a parachute

and something else
like a bouncy ball

inflated around the spacecraft.

♪

I don't think a human crew
is going to be too pleased

if they're gonna be bouncing
onto the surface

in an airbag,
rolling to a stop, right?

Narrator:
To land people on mars,
nasa will need some new tricks.

The 2020 rover will overcome
the challenge with the advanced

supersonic parachute inflation
research experiment,

a.S.P.I.R.E.

It will rapidly
slow down the craft

with the force
of an airplane jet engine.

This is fine for the rover.

It's actually gonna work
no problem.

But it's not going to work
for people.

Narrator: A human lander
will weigh far more

than the 2,300-pound rover.

Not even supersonic parachutes

could land a crew
safely on mars.

Nasa will need a new plan.

One idea is to use
the thin martian atmosphere

in a unique way.

There's an idea of coming
in really fast,

getting to the thick part
of the atmosphere,

and then going horizontal
to the ground

and gliding and losing
your momentum that way.

Narrator:
As the astronauts descend,

they tilt the nose of the lander
towards the martian surface

aiming for the thickest part
of the atmosphere

close to the ground.

Then they pull up
at the last second

using friction from the
atmosphere to slow the craft.

Descent engines switch on
for the final touchdown.

♪

radebaugh:
Is this a crazy idea?

I mean, yeah,
it's a little bit weird.

I don't know if we'd really
think about it,

doing something like this,

but, I mean, you've got to think
outside the box sometimes.

Narrator:
Right now, nasa's plans
for landing a craft on mars

are still on the drawing board.

But even if they can
get astronauts onto the surface,

the thin atmosphere
isn't done with them yet.

It causes swirling
dust storms

that cover
the planet's entire surface.

Oluseyi: Mars doesn't just have
dust devils.

It has dust hell.

Narrator:
And these towering clouds
have killed before.

♪

narrator:
If nasa's astronauts arrive
on mars as planned, in 2035,

the settlers will find
one of the red planet's

biggest challenges is its dust.

It's sticky,

basically,
light from the sun

can give the stuff
a static charge

and then it clings to stuff.

So it's not just a matter
of, like, you know,

standing on a doormat
outside your your space habitat

and shaking yourself off.

Durda: It's gonna get
in your space suit.

It's gonna coat your visor.

It's going to cover
your solar panels.

Plait:
If you get it in your lungs,
it's not a good thing.

We have to figure out how to
clear this stuff out.

Man: 300 feet.
[ speaks indistinctly ]

narrator:
Through the '60s and '70s,

apollo astronauts
walked on the moon.

When they returned
to their landing module,

they brought moon dust back
with them.

The lunar dust clogged seals,
caused equipment to overheat,

and resulted
in false instrument readings.

It even made
the astronauts sick.

You don't want to be breathing
in fine, dusty material

by itself, you can get things
like silicosis.

It's, you know,
almost basically a lung cancer

that you can get just
from breathing the dust itself.

You don't want to do that.

Narrator:
The red planet is covered
in sticky dust,

and new research suggests
it all came from one place...

...The medusae fossae formation.

When the 600-mile-long
volcanic deposit formed

3 billion years ago,

it was around half the size
of the united states,

but the martian winds
have eroded this structure

and spread the dust
across the entire planet.

When the wind whips
up this dust,

it can have
disastrous consequences.

Lanza:
The real problem is just that
all these fine particles

get lofted into the atmosphere,

and it takes a really long time
for them to settle back out.

And what the dust does
is it just gets up in the sky

and it sits there
and sits there and sits there.

Narrator:
As more material gets lifted
into the atmosphere,

it forms huge dust storms.

The storms are so large
they block out the sunlight

and cool the martian surface...

...Creating
a temperature difference

between the ground
and atmosphere

that causes winds to increase
and the storms to grow.

And nasa's opportunity
rover knows firsthand

the dangers of being
trapped in one.

Opportunity was a nasa rover
sent to mars

to hunt for signs of past water
on the surface

and potentially signs
of past life.

Lanza:
This is a rover that we really
worked with so long,

knew so well,
and who had come up with

so many amazing new results
from mars.

Narrator: June 2018.

Opportunity was
15 years into its mission...

...When giant clouds of dust
appeared on the horizon.

Nasa could only watch
as the storm grew and grew.

Once this dust storm coated
the entire planet,

it blocked the sun.

And the sun was the source
of opportunity's power.

Opportunity works
using solar panels,

and so it gradually got less
and less and less electricity.

Narrator: For opportunity,
there was no escape.

Lost in the darkness,

opportunity's power reserves
slowly ran dry.

The rover fell silent.

We thought, well, maybe
once the dust storm clears up

the panels can fire up again
and we can get it back,

but it just never woke up.

Narrator: If nasa's astronauts
do make it to mars,

the storms could damage more
than the crew's power supply.

[ thunder crashes ]

when the storms begin to blow,
they crackle with electricity.

Just like you can create
a static charge

by rubbing your foot
on the carpet

or a balloon on your hair,

this happens at large scale
in these dust storms on mars.

The sand grains rub up
against each other,

and that creates
a static charge.

So you get these electrical
flows that occur.

Durda:
Here on earth, we see this
in volcanic eruptions

as the dust,
the ash burbling out

of one of these huge eruptions.

You'll see lightning discharges
in those volcanic plumes

from this same
charge transfer.

Stricker:
If you're in a place with a
lot of electrostatic discharge,

that means sparks
are going to fly,

which is really terrible
for operating instruments.

Narrator: To survive on mars,

the settlers are going to need
a protective shelter.

The keyword to living
on mars is protection --

protection from the cold,

protection from the lack
of atmosphere,

protection from the radiation
from space.

Narrator:
Nasa could build shelters,

but martian history
offers them a shortcut.

Millions of years ago,

the planet's volcanoes
erupted huge amounts of lava.

Radebaugh:
But the silver lining is that,

as the lava was flowing away,

it did that
through underground tubes.

And then as the lava
evacuated away,

it left behind empty caverns,

just like this really
big lava tube

that we're standing in
right now.

Narrator:
Martian gravity is a third
as strong as earth's

thanks to the red planet's
lower mass.

So when martian lava flows
underground,

it meets less resistance

and can carve out
monstrous cave systems,

natural astronaut shelters

hidden away
from the dust storms.

If you actually then seal them,
you can fill them with air.

You've got
a great place to live.

These tunnels are ready-made
for people to move into.

We already have the keys.

Narrator:
But a lava tube may not be
everyone's idea

of home sweet home.

Because they're
a natural feature,

you can't pick and choose
where they are.

You have to go
to where they already exist.

Narrator:
Building their own shelters

gives the astronauts
more choices,

and they can be built
by robots

before the settlers even arrive.

Plait: And we could even send
3-d printers.

I'm talking about something that
actually uses the rock there

and makes something
like concrete,

and it could build structures
for us to live in.

Narrator: Even with shelters,
the settlers will still need

to eat, breathe, and drink.

But there is no food,
no breathable oxygen,

and no liquid water on mars.

So even though mars is the
closest friendly environment

to life that there is
to the earth,

it's really not
all that friendly.

Narrator: Without easy access
to the essentials of life,

will settling on mars
be possible?

♪

narrator: Humans have evolved
to life on earth.

We have oxygen to breathe, water
to drink, and food to eat --

everything we need to survive.

Compared to earth,

life on mars
is a recipe for disaster.

If you look at it as a human
being who wants to live there,

yeah,
this is an alien world

that's going to try to kill you
at every step.

Stricker:
It's far away. It's cold.

There are just
so many reasons why

we really wouldn't be
happy campers on mars.

So why on earth
are we talking

about sending people there?

Well, the next closest planet,
venus, it's way worse.

Its surface is super hot.

It's got horrible chemicals
in the atmosphere.

So in comparison,

mars looks like
a great, great place to visit.

It's close,
it's relatively earthlike,

and although
there are many challenges

they're challenges
that we could overcome.

Narrator: To settle on mars,

nasa's astronauts
need a few essentials.

If we want to live there,
short term or long term,

you know,
what do you need physically?

Well, you need air.
You need water. You need food.

Those are all things
that we can bring with us,

but it's a lot easier
if they exist there on mars.

Narrator: The settlers will need
to grow their own food,

but the martian ground
is poisonous.

Mars' dust
looks really benign.

It looks kind of like dust
you would find in southern utah.

But it turns out it contains

a lot of something
called perchlorate,

and these materials
are really toxic to human life.

[ thunder crashing ]

narrator:
Perchlorates are chemicals
formed by electricity

produced in martian dust storms.

And they make up about
1% of the martian soil

which doesn't sound like much,

but this could be
a significant problem

for any humans living on
the surface of the red planet.

Narrator:
Food grown in the martian dirt
will absorb the perchlorates,

posing a health hazard
for the astronauts.

But that's not all.

Direct exposure
to the toxic soil

will make astronauts
very sick.

One of the effects
that perchlorates

have biologically in our bodies
is to sort of mess with

and alter the function
of our thyroid glands.

Narrator:
Astronauts would get rashes
and feel nauseous.

Extended exposure to the dirt
could even kill them.

And mars is not
the sort of place

where you would ever want
to get seriously ill,

millions of miles from all
the hospitals

and health care
of the earth.

Narrator: There are ideas of how
to clean the poisonous soil

using water or bacteria,

but the technology
is not yet ready.

The first settlers will need to
find a safer way to grow food,

and nasa has the solution --
hydroponics.

Hydroponics will provide
all the food

a martian settler might need.

Instead of growing in soil,
the settlers grow crops in water

so all you need to do
is bring the seeds or the plants

and then have them grow
right there in water.

But if we decide to grow our
crops hydroponically on mars,

then we still have this problem

of needing lots
and lots of water.

Narrator: Before astronauts
water their plants,

they'll need water to drink,

and mars hasn't had running
water for millions of years.

We've all seen the movies
of people

stranded in different places
and having to survive

and they can last
for months without food.

But a human cannot last
beyond three days without water.

Narrator: Astronauts on
the international space station

recycle water from bathing,
breath, urine, and sweat,

but they still need
1,500 gallons sent up each year.

Each delivery weighs
over six tons.

Transporting water to mars

will add a lot of weight
to the manifest.

You have to use fuel
to launch it

but then you also
have to use more fuel

to launch the weight
of the other fuel,

and so on and so on.

You have to keep to
an absolute minimum

the amount of weight
you try to launch from earth.

Narrator:
So if nasa wants to set up
residence on mars,

astronauts will need to find
a water source.

Even though no liquid water
exists on the planet's surface,

there are other places to look.

It turns out there
is a lot of water on mars.

It's trapped underneath
the ground beneath the dirt

and the soils at high latitudes.

It's also found in huge volumes
up at the polar ice caps.

Plait: Ice -- you melt,
and it becomes water.

You can drink it.
Yay.

You can grow plants
and do things like that.

In fact, if you were to melt
all of mars' polar ice,

then you would be able
to cover the globe in water

plait:
So ice is an extremely important
thing to have access to.

So if we do go to mars
to explore and live there,

following the ice
is the way it's going to go.

Narrator:
Even if nasa's astronauts
can turn the martian ice

into drinking water,
without another resource,

settlers will be dead
in three minutes --

oxygen to breathe.

There is oxygen on mars,
but it's not in the air.

You can't breathe it.

It's bound up in the dirt
and combined with iron

to make iron oxide, giving it
its characteristic red color.

And so we need
to bring it with us,

and that's a huge amount
to bring,

or we need to make it at mars,
and that's really difficult.

Narrator: We can deliver oxygen
to the I.S.S.,

but the trip to mars is long

so there will be
few supply missions.

Once you're on mars,
you can't pull out your app

and order an oxygen delivery
to your door.

You got to take it with you,
and that's a lot of oxygen.

Narrator:
Nasa astronauts will need a way

to make oxygen
on the red planet,

and the space agency
is working on a solution.

When their 2020 rover arrives
on mars, it will carry out

the mars oxygen in-situ resource
utilization experiment,

or m.O.X.I.E.

M.O.X.I.E. Will take carbon
dioxide from the martian air.

And use electricity to split
that co2 and release oxygen

that astronauts could breathe
in the future.

Narrator:
This test will create oxygen
on another planet

for the first time,

but m.O.X.I.E. Can't make enough
for a crewed mission to mars.

M.O.X.I.E.
Will be able to make

about half a pound
of oxygen per day,

which is only enough to keep a
human alive for about six hours.

Narrator:
Nasa needs to significantly
scale up the technology

to support a whole crew on mars.

But even if the astronauts
can survive on the red planet,

can they actually reach it?

Radebaugh:
This is a long trip in a bathtub
with three other people.

It's really challenging.

I think we're still
asking ourselves this question,

how will we do it?

♪

narrator:
Nasa plans to put boots on mars.

To achieve this, you need
to carry a lot of stuff.

Sutter: You need oxygen,
you need medical supplies,

you need food,
you need stores of water,

you need some fuel
if you want to come back,

and all this has to be packed
into an incredibly tiny volume.

Narrator:
Nasa's solution -- orion,

a 28-ton spacecraft nearly twice
the mass of a school bus.

The rocket that launches orion

will need to produce
millions of pounds of thrust,

and that is a problem.

If we decided tomorrow, like,

"hey, you know what?
Let's go to mars."

we can't.

We don't have powerful-enough
rockets to do it.

Narrator: In 1969,
nasa's saturn v rocket

fired apollo astronauts
to the moon

with 7.6 million pounds
of thrust.

That's the power of more
than 34 jumbo jets.

A saturn v could have sent
astronauts to mars.

Not anymore.
We stopped making them.

Narrator: To break free
from earth's gravity,

the space rocket must travel
at 25,000 miles an hour.

To achieve that,

nasa is building the most
powerful rocket in the world.

The space launch system,
or s.L.S., is the rocket

that's being designed
to carry orion off of earth

and beyond low earth orbit.

Sutter:
And the philosophy is, "hey,
remember those big rockets

that we used to make back
in the '60s and stuff?

Let's do that again
but more so."

radebaugh: It's really big.

It's larger than
the saturn v rocket

that was built to carry
the apollo spacecraft

and is therefore going to be
the largest rocket built.

Narrator:
The space launch system
will be taller

than the statue of liberty.

Its gargantuan engines
will thrust the rocket

through the atmosphere

with the horsepower
of 160,000 corvettes,

producing 8.8 million pounds
of thrust.

The s.L.S. Will be able to blast
the orion capsule into space

and send it on its way to mars.

Unfortunately, the rocket
has fallen behind schedule.

Its maiden test flight was set
for December of 2017.

Now it's scheduled
for the end of 2020.

Critics see the s.L.S.
As a waste of money,

with the project reported to be
billions of dollars over budget.

It's still hoped
nasa's space-launch system

will go to mars
in the 2030s.

But even though the red planet
is our neighbor,

the timing of our visit
will be complicated.

Plait: If you're planning
a family vacation

and you want to get in the car,
it's easy, right?

You look at a map
and you say I live in city "a"

and I want to go to city "b"

and I'll just take
the highways there."

well, great.

Now imagine that city "a"
is moving this way

at 50 miles per hour,

and this city is moving this way
at 200 miles per hour.

Now what do you do?

Well, that is a very
small problem

compared to getting
to another planet.

The timeline
of a mars mission,

the scheduling,
if you will,

is all governed
by celestial mechanics,

the orbits of the planets.

It's not just
you pick a time to go to mars

randomly
whenever you feel like going.

You've literally got to wait

for the planets
to be aligned, right?

Thaller:
On average, the distance
from the earth to mars

is about 140 million miles.

But this is changing
all the time

because we are both plants
that are orbiting the sun.

So about the closest
that earth ever comes to mars

is a distance of about
35 million miles.

Durda: But on other times
when we're on the opposite side

of the sun from mars,

it can be as much
as 250 million miles.

Narrator:
Launching near the time

of mars' closest approach
shortens the journey

so nasa can save on fuel
and resources,

boosting the mission's
chances of success,

but this planetary alignment
only happens every 26 months.

So if nasa misses
a launch window,

it'll have to wait over
two years for another go.

But simply picking
the right time isn't enough.

Mars and the earth
are both orbiting the sun.

So orion can't fly
in a straight line to mars.

Instead, it'll use what's known
as a hohmann transfer.

What we want to do is sort of
put ourselves on our spacecraft

in orbit around the sun

so we might start right here
on earth,

launch our spacecraft,

and, essentially,
we just make a nice, gentle arc

that's arcing around the sun

so that it can naturally slide
into this orbit

and then end up on mars.

Narrator: The journey will take
around 10 months.

To get there quicker means
burning more fuel,

which is not an option.

The hohmann transfer
keeps fuel usage low

by putting the craft
in an orbit

that gradually intersects
with the orbit of mars

before being captured
by the red planet's gravity.

But the crew will need to get
their direction just right.

Durda:
The way the orbits work,

you've got to aim a little
bit different direction

from where mars appears
to be now.

You got to aim for where it's
going to be when you get there.

This has to happen so that
it can naturally slide

into this orbit
and then end up on mars.

If we miss that precision,

then we just could end up
hurtling out into space.

Narrator: Even if nasa hit
their target.

The crew still has a long
10-month journey in space.

The human body is just simply
not designed

for long-duration space travel.

Narrator: Space travel
can destroy bones,

weaken heart muscles,
and even mess with the mind.

Could a cruise survive
the journey to the red planet?

♪

narrator:
Nasa plans to put humans on mars
in the 2030s.

Rocket technology will be pushed
to its limits.

But the greatest hurdle
is our own fragile bodies

out there in a spacecraft
between the planets,

all bets are off.

It's going to be
a dangerous trip.

Irwin: Both hands down
to about the fourth rung up.

Narrator:
When astronaut james irwin
stood on the moon,

his heart beat irregularly.

Back on earth,
irwin suffered heart attacks,

which eventually proved fatal.

A 2016 study found
that apollo lunar astronauts

are four to five times
more likely to die

from cardiovascular disease

than astronauts
who never left earth's orbit.

One cause could be
deep-space radiation.

And the radiation
in outer space

won't just be damaging
the heart muscles

but also the nervous system

and astronauts' brains
in outer space.

Narrator:
Astronauts heading to mars
will face radiation

created in the core of stars.

Some comes from our sun
when solar ejections

throw out streams of deadly
charged particles.

♪

there are also cosmic rays
from outside the solar system.

Created in supernovas,
the death of giant stars,

these energetic particles

race through the galaxy at
close to the speed of light.

And you don't want to be
exposed to too many of them.

In low doses, it's not a problem
at all, really.

But in high enough doses,
these things penetrate ourselves

and damage our dna
and over the long term

can cause really bad damage
to human bodies in space.

Narrator:
The longer you stay in space,
the greater the danger.

Durda: Remember,
our missions to the moon

were on the order
of a week or two.

A mission to mars,
at the minimum,

is going to be
something like two

or two-and-a-half years,
probably.

Narrator:
These cosmic bullets can
cause mutations and even cancer.

New research from 2019 suggests
space radiation

will cause memory loss

in one to three astronauts
on a mission to mars.

Darnell:
And it's not just a problem

of forgetting where
you've left your keys.

Trying to come back in through
the airlock, you do not want

to be forgetting
emergency procedures.

So we're going to have
to really consider,

how do we mitigate
the effects of this radiation

to make it possible
for people to go to mars

and actually spend some time
without being ill?

Narrator: So the ship
needs to protect the astronauts.

Plait: Well, you think,
"well, I would just,

I don't know, build a spaceship
out of really thick lead.

Like, well, that weighs a lot,
and it turns out

lead doesn't protect you
from this kind of radiation.

You need something else.

Well, there is something else

that protects you
from this radiation,

and that's water.

We need to bring lots
and lots of water

to drink and cook with.

And if we just place
that water in a layer

around our spacecraft,
that can absorb the cosmic rays.

You might think, well,
you're drinking the very water

that using to stop the radiation
that's causing damage to us

won't the water be dangerous
to drink it?

It doesn't really work
quite like that.

You're just taking one
high-speed subatomic particle

and changing it into another one

as it gets captured
by the water.

Water's still gonna be safe
to drink, fortunately.

Narrator:
But even if nasa can shield
its astronauts from radiation...

...Space causes other
health issues.

Your bones are starting
to demineralize.

They're getting weak.

You're getting arthritis
even in the prime of your life.

Narrator: Weightlessness
during a 10-month journey

will thin the astronauts' bones.

Muscles will waste away,

making walking
on landing difficult.

We've evolved.

We've grown up
on a planet with gravity.

And as soon as you're
an astronaut in outer space

floating around
in weightlessness,

it looks like a lot of fun

but, actually, your body is
deteriorating from the inside.

Narrator:
Astronauts need assistance
to walk when returning to earth.

If nasa's mars crew arrive
on the red planet

in a poor physical state,
they won't be able to function.

[ indistinct talking ]

intense exercise regimes
in space

would help the crew
stay fit and healthy.

But we're in the dark

about the full impact
of extended space travel.

On a mission to mars,

bodies will be pushed
to the extreme.

To say that sending humans
to mars

is a challenge
would be an understatement.

We could be ahead of ourselves.

Plait: Eventually we're going
to lose people doing this,

and that's something
we have to face.

The question is,
is it worth it?

Narrator:
But there may not be a choice.

We know that, over time,

this planet
is not going to be habitable.

So we really should consider

if there are places
we can go outside of earth.

♪

narrator:
Nasa's mission to mars

will be the toughest
undertaking in its history.

The launch from earth will be
a monumental challenge...

...The journey to mars
filled with danger,

and survival on
the red planet will be a test

unlike anything
nasa has faced before.

It's easy
to make a bullet list

of of why going to mars is hard.

And that's going to be
a long list,

and those bullet points
are going to be scary.

A lot of these
are serious problems.

Narrator: Nasa's mission to mars
needs to be a success.

Earth is in danger

from climate change

to asteroid strikes

to nuclear destruction.

We need an escape plan.

Radebaugh:
Earth may just need a lifeboat
in the future.

We are growing very quickly,

and we're using
a lot of our resources.

We're changing the planet.

Walsh:
We're looking for a lifeboat.

Maybe mars is the closest,
best chance we've got.

Narrator:
Despite the challenges,

nasa's goal is to send
the orion spacecraft to mars

in the 2030s.

But to do that,
we need a rehearsal.

Durda: I'd love to
see us go to mars.

I would love to go myself.

But it might be nice
to have a little bit of practice

before we try it.

Narrator:
Where better to practice than
a destination closer to home.

The ultimate aim is to get
humans to mars, and one approach

is to first have a goal of
getting humans back to the moon.

Narrator: Orion will first make
the shorter trip to the moon.

Lanza:
There are a lot of advantages
to using the moon.

We can test out different
scenarios for operations

we can also
test out technologies

much more close to home, and so
if something were to go awry,

we can much
more easily intervene.

It's a little bit safer.

If we send people to mars,

you know, it's going to be
a lot harder for us

to help them if they need it.

Narrator:
Nasa's orion moon missions
will be far more

than just a training exercise.

They'll use them to build
a lunar outpost called gateway,

a space station in orbit
around the moon.

It's actually a lot easier
to do that

than trying to build
something on earth

and get it out of earth orbit.

Narrator: Six planned missions
will build and maintain

a space station
in orbit around the moon.

It will be a proving ground
for the technology

and the science that will
help us get to the red planet.

And once nasa
has ironed out any problems,

the real mission can begin.

Gateway won't simply be
a small step for man.

It'll be a springboard
to another planet.

When we first sent humans
to another planetary body,

it was the moon, and we had
never done that before.

So now we've got the moon
under our belt.

We know something about how to
send people to another planet.

We don't yet have all the
technologies that we might need

to send humans to mars,
but we're well on our way.

Narrator: As nasa begins
its journey to the red planet,

not everyone is on board.

A lot of people think of mars
as our lifeboat

just in case
we screw things up on earth,

but we really need
to take care of our own planet.

If you want to go there
and explore

or build a base,
more power to you.

But I'm going to stay

where it's a little bit
more green and blue.

♪

narrator:
Even so, nasa is already
building rockets

and testing the technology.

The stage is set for humankind's
greatest adventure.

I think we will send humans
to mars.

It's just a really, really,
really big problem

that we have to figure out
how to solve.

But we're good
at solving problems.

Given the human mind
and how curious we are

and how much we like
to climb the next mountain

and achieve the next
challenge, mars is right there.

Radebaugh: There is something
in the human psyche

that will send us to mars
despite all of the challenges.

And so for sure
we will go to mars.

Stricker:
Even though it's extremely
difficult to go to mars,

the answer is always yes

if somebody asks me
if we should go

because that's
the ultimate goal.