All language subtitles for The.UnXplained.Mysteries.of.the.Universe.S01E02.1080p.WEB.h264-EDITH_track3_[eng]

WILLIAM SHATNER:
Genetically-modified astronauts,

massive underground bases
on Mars

and futuristic rockets
that will send humanity

across the universe.

Humans have been traveling
through space

for more than 60 years,
and during that time,

we've put men on the Moon
and robots on Mars.

But how much further can we go?

Will we be able
to send astronauts

to the far reaches
of the universe?

And when we arrive
on these strange new worlds

will that make us...

alien earthlings?

Well, that is what
we'll try and find out.

♪ ♪

SHATNER:
Since the dawn of humanity,

Earth has been the only home
we've ever known.

Mankind has explored, settled

and conquered nearly every nook
and cranny of our planet.

Now, tens of thousands of years
into the age of modern man,

it seems that the only place
left for us to go

is up.

GRAHAM LAU:
For all that we know
from our history,

we humans are explorers
in our very nature.

And so, it seems to make sense
that we would want to go out

and explore the other worlds
of our solar system and beyond,

and maybe even settle there

to send people
to live, perhaps permanently,

in the other worlds
that exist out there.

MICHIO KAKU:
It is a law
of physics, practically,

that one day, we will have
to leave the planet Earth.

We have to have an escape clause

in case
something devastating happens

to threaten the very existence
of human life.

In fact, one of the goals
of NASA is

to create a Martian colony
with human inhabitants.

And so, why not this be
the destiny for humanity

to become
a multi-planet species?

But then,
the bigger question is

is it possible?

SHATNER:
Could humans really become
a multi-planet species?

For over a century,

science fiction and fantasy
have explored the concept,

but what would it actually take

for us to become
alien earthlings?

BEN McGEE:
One of the greatest challenges

in sending humans off-world
is that frontier explorers

in outer space
are gonna face hazards,

the likes of which
no humans have had to face.

It's barren and inhospitable,

there's a lack of oxygen

and lack of resources in space,

so, it's treacherous.

Self-sufficiency
is going to have to be key,

and it's gonna be a struggle.

SHATNER:
The Baikonur Cosmodrome, Russia.

April 12, 1961.

A Vostok 1 rocket launches
into the sky,

carrying only one passenger--

Soviet cosmonaut Yuri Gagarin.

For 108 minutes
of a single orbit around Earth,

Gagarin becomes
the first human being

to leave our planet
and journey into space.

McGEE:
Yuri Gagarin is

literally the first
alien earthling.

He was up there
for only about an hour,

on a Vostok rocket,

and this is only
a little bit more generous

than a cannonball
with a human being inside,

fired all the way up into space
and then falling back.

So, truly,
these first cosmonauts

were pioneers
putting themselves at risk.

Yuri was regarded
almost universally as a hero.

(cheering)

He was celebrated the world over

as the first human being
in space.

AMY TEITEL:
Gagarin's flight took all
of America by surprise,

and everybody suddenly
kind of stops what they're doing

to learn about this,
to watch the newsreels.

And in the 1960s,

everything about space flight
was unknown at the time.

They didn't know if astronauts
were gonna lose their minds

and space madness
would kick in.

Also, there were questions
like, "Will your eyes distort

"without gravity,
and you can't see?

Can you swallow
without gravity?"

No one knew anything,

and then Yuri Gagarin
goes into orbit.

And the reality of humans going
into space is suddenly here.

SHATNER:
In a speech at Rice University,

President John F. Kennedy
announces an audacious plan.

Just 17 months after
the first manned orbit of Earth,

America is planning
to put a man...

on the Moon.

We choose to go to the Moon
in this decade

and do the other things,

not because they are easy,
but because they are hard.

SUSAN KARLIN:
JFK announcing

that we were gonna
go to the Moon

ignited imaginations.

It was tremendously exciting
for the American public.

However, the engineers
that actually had

to make it happen
were a little unnerved

because America was still
at the infancy

of getting into space.

At that point, we really didn't
even know what we didn't know.

Now, this was
a very dangerous thing to do,

because the Apollo
lunar missions were flown

right on the edge

of what are called
"single points of failure."

If a certain rocket engine
didn't ignite,

they couldn't leave the surface
of the Moon.

So, it puts astronauts
in significant danger.

But this was the nature
of spaceflight then.

We were taking a lot of chances.

SHATNER:
In less than seven years

from JFK's bold proclamation,

and with the help
of over 400,000 scientists,

engineers and NASA personnel,

Apollo 11 launches
into outer space.

SHATNER:
After a journey

that lasts four days,
six hours, and 45 minutes,

the lunar module lands
on the Moon.

TEITEL:
When Apollo 11 landed
on the Moon,

everyone kind of
stopped to watch,

because I think
there was probably

this almost morbid curiosity
of like,

"If this works, this is amazing,
and if this doesn't work,

I want to see
what's gonna happen next."

I mean, whatever was
gonna happen, you had to see it.

KARLIN:
The Apollo 11 Moon landing
was astonishing.

I mean, people were glued
to their TV sets,

riveted by the fact that there
were two men on the Moon.

And then you'd go outside,

and we'd look at the Moon,
and say, "Oh my God,

there are actually
two people on there right now."

And it was mind-blowing.

SHATNER:
After the success of Apollo 11,

NASA landed ten more astronauts
on the lunar surface.

But after three years
and six manned missions,

in 1972, the United States

shut down
the costly Apollo program.

And since then,
humans have not been back

to Earth's closest neighbor.

But could the Moon
serve a strategic role

in our quest
to explore the solar system?

The White House.
December 11, 2017.

President Donald Trump
signs Space Policy Directive 1,

which authorizes NASA to send
astronauts back to the Moon.

And, incredibly, the initiative
also sets the stage

for the construction
of the first-ever moon base.

TRUMP:
The directive marks
an important step

in returning to the Moon.

This time,
we will not only plant our flag

and leave our footprint.

We will establish a foundation
for an eventual mission to Mars,

and perhaps someday,
to many worlds beyond.

KAKU:
We're entering the second
golden era of space exploration.

The first golden era took us
to the Moon,

but it is
a whole new ballgame now.

Realize that there's a plan,

there's a design
behind all of this.

We're talking about
an interplanetary highway system

that goes between Earth,
the Moon and Mars.

In other words, it's different
from all other missions.

SHATNER:
While the idea of a moon base
that will allow us

to travel to deep space
sounds like science fiction,

NASA plans to invest more
than $100 billion

in making it a reality.

The program is called Artemis.

-Your Artemis 2 crew!
-(applause and cheering)

SHATNER:
And a mission to land both a man

and the first woman on the Moon
will take place in 2026.

Once we've returned to the Moon,
the next stop is Mars.

LAU:
Going to Mars from the Moon

requires a lot less fuel
to begin with to get us there.

That leaves more mass for us
to send things like extra water,

extra food, more people,

to prepare us for other kinds
of exploration, like

going to the other worlds
of our solar system.

SHATNER:
Will humans succeed
in colonizing Mars,

and perhaps
even more distant planets?

It's an exciting thought,

but in order
to become alien earthlings,

we first need to figure out
how to protect astronauts

from the dangers
that they will encounter...

in outer space.

SHATNER:
For over six decades,

mankind has made
tremendous progress

in space exploration.

From satellites and probes
to robotics

and a manned space station,

we continue to test the
boundaries of humans in space.

But while the idea
of becoming alien earthlings

fills us with wonder,

the harsh reality is that
the vacuum of space is lethal

to the human body.

We very much evolved to live

on the surface of a world
like the Earth.

But space is very hostile
for life as we know it.

The space environment itself
is extremely cold.

There's not enough oxygen
for humans to breathe

in the vacuum of space.

There's also radiation
coming from our Sun,

coming from other stars.

And there are other dangers,

things like micrometeorites

and other possible objects

that can strike astronauts
when they're in orbit.

And so there's a lot
for us to overcome

when it comes
to the challenges of space.

PYLE:
The problem with human beings is
we're basically fragile things.

We're big, mushy, wet bags
of muscle and water,

and everything about space
wants us dead.

So, when you go into space,

you're always kind of flirting
with the edge of disaster.

SHATNER: As earthlings
venture further off our planet,

how can we protect
the human body

from the dangers
of space travel,

especially when an astronaut's
carefully designed clothing

and equipment could be
the difference between life

and death?

Four years before
the Apollo 11 moon landing,

Soviet cosmonaut Alexei Leonov

prepares to boldly go
where no man has gone before.

One of the earliest tales
of extreme danger in space

was during the Voskhod 2 flight
of the Soviet Union

back in the early 1960s.

This was
the first spacewalk ever.

Alexei Leonov was to depart
the Voskhod capsule

in his pressure suit

to basically drift
for about 12 minutes.

He was at extreme risk
of suffocation or worse.

SHATNER:
On March 18, 1965,

the two-man crew of Voskhod 2
reaches orbit

and Alexei Leonov prepares
to be the first human

to set foot
in the cold vacuum of space.

PYLE:
They open the hatch.

The cosmonaut drifts in space.

Looks like he's having
a great time, but, in fact...

...his suit pressure
was increasing.

The suit was becoming
very rigid,

and he suddenly realized that
the suit had inflated so much,

he wasn't even able to reach
down and trigger the camera

to take the pictures
he wanted to

and he couldn't fit
through the hatch anymore.

(yelling in Russian)

Leonov's over-pressurized suit
had ballooned to the point

that he could barely move...

...leaving him stranded
in space,

nearly 120 miles above Earth.

To save his own life,
Leonov had to think fast.

Leonov had to sit there and
manually bleed off air pressure

from a little valve...

...on his space suit
and depressurize.

He did eventually
depressurize enough

to get back inside the capsule.

By that time,
he estimated that he had

between two
and three quarts of sweat

sloshing around in his boots
from the exertion.

He could have easily
passed out and died.

SHATNER: The harrowing story
of man's first spacewalk

is a stark reminder of the grave
dangers astronauts face

when confronted by the harsh
reality of outer space.

But could even the best
technology and fabrication

create suits that could
truly protect future astronauts?

Or does the answer
to human survival in space

include modifications
on a cellular level?

The International Space Station.
May, 2019.

NASA astronaut Christina Koch

conducts a revolutionary
experiment in zero gravity.

Using a technology
known as CRISPR,

she is able to repair genes
inside yeast cells.

But what is the purpose
of this radical experiment?

Could this technology
be the solution

to modifying humans
for survival in space?

There's something
called transhumanism,

which is the movement to try
to perhaps prepare for the day

when we have
to genetically modify ourselves

to explore the universe.

Eventually, we may use
genetic interventions

in the form of CRISPR technology

to change our genes
and our body organs biologically

so that we can adapt to hostile
environments in outer space.

REBECCA BOYLE:
This experiment in microgravity

shows that we have
a lot to learn

about how to optimize humans
for space travel,

and one of
the most important things to do

would be to survive the
radiation environment in space.

If you leave Earth, you no
longer have Earth shielding you

from cosmic rays

and really damaging radiation...

...that can harm our DNA...

...and do things
like cause cancer.

So it would be interesting
to find out

if there are ways to manipulate
our genetic material

to make it less likely for us
to suffer those health effects.

SHATNER:
Will CRISPR technology
help us rewrite our DNA

to withstand deadly radiation

while traveling
through outer space?

Perhaps.

But what about other side
effects of living off-planet,

like the weakening
of bones and muscles?

One potential solution involves
augmenting the human body

with advanced robotics.

KAKU:
Our bodies,
because of evolution,

are fine-tuned

to exist
in a gravitational field

of the planet Earth.

So, as we explore outer space,

we're getting weaker and weaker.

Some people say that it might
be possible to compensate

by using modification devices
called exoskeletons.

Believe it or not,

we can connect the human brain

directly to a suit of armor

that is controlled artificially.

For example,
a few years ago in Brazil,

the World Cup soccer game
was initiated

by a man
who was totally paralyzed.

And the scientist
connected his brain...

...to an exoskeleton

to enhance
his mechanical abilities.

In the future,
it'll be streamlined.

Astronauts would have
this suit on

and would have, in some sense,
the superpowers of Iron Man

on a distant planet.

LAU:
There are many challenges,

and there are certainly
a lot of questions involved

when it comes to modifying
what the human is.

But it still makes sense
that if we truly want to go out

and explore the stars
that we would choose

to change ourselves
to fit the space environment.

Will astronauts
become robotically enhanced

and genetically modified
alien earthlings?

It's a fascinating prospect.

But in order to reach
distant planets,

we have to do more
than protect our bodies.

We also have to create
new rockets that can take us

across the vastness of space.

SHATNER:
As part of its Apollo program,

NASA prepares to test
its newly designed

super heavy-lift launch vehicle,

the Saturn V rocket.

MAN:
We have ignition.

All engines are running.

We have liftoff.

SHATNER:
Built specifically for
human exploration of the Moon,

the Saturn V rocket
would successfully launch

26 astronauts into space.

But this monumental achievement

would require a massive vehicle

in order to propel man
into lunar orbit.

The problem
with the Saturn V rocket

is it's, like, 12 747s
all stacked together.

And then when you look at what
we actually sent to the Moon,

the lunar lander
and the return vehicle,

that was about 35,000 pounds'
worth of payload.

But the Saturn V rocket itself
was 6.5 million pounds.

That means more than 99.5%
of the system

was the rocket
that didn't go to the Moon.

PYLE:
Traditional rocket engines
are very effective

for short distances,
but what they don't do well

is run for extended periods
of time.

And if you really want
to go deep into the universe,

you need something that's
ultrareliable, very simple

and can run for hours
and hours and hours.

SHATNER:
While the concept
of deep space travel

has both entertained and
inspired us for over a century,

the question remains, how will
humans cross the vast distances

it takes to get
to other planets?

Will scientists and engineers

be able to create
next-generation rockets

that will take humanity further
and faster than ever before?

NASA makes
a surprising announcement

about the future
of space travel technology.

They intend to build
a rocket called DRACO

that is driven
not by conventional fuel

but rather by one of the most
powerful and hazardous forces

known to man:

nuclear reactions.

MICHAEL DENNIN:
When we think
about nuclear rockets,

it's very different
than an atomic bomb.

With an atomic bomb, you're
actually creating an explosion

from the nuclear fusion
reactions.

When you think
about a nuclear engine,

it's a lot more like
a nuclear reactor,

which is much,
much more efficient

and takes a lot less mass.

McGEE:
With a normal rocket,

you need fuel so it'll burn,

and that's what provides thrust.

But with a nuclear rocket,
nothing burns at all.

You just take
a really cold liquid,

pump it really fast
through a nuclear reactor,

and you just let it go.

And it's basically

twice as fast
as our best rockets today

using half the fuel.

PYLE:
DRACO will solve
a lot of problems.

This is something that can
go longer distances

faster, more efficiently, than
anything we've used before.

For instance, going to Mars,

the chemical rocket could
take up to seven months.

Nuclear rockets will be able to
cut those times down

by anywhere from 30% to 50%.

So, it makes it

a lot easier for people to go

from one place to another.

SHATNER:
NASA has announced
that DRACO will be ready

for its first test flight
in 2027.

But assuming
the rocket is successful,

we still have
another problem to face.

Because even with the fastest
space ships imaginable,

traveling to other worlds

will take longer than
the average human's lifetime.

The biggest challenge
with being multiplanetary

is the vast distances
between the planets.

Going to another planet, even
with our fastest spacecraft,

would require hundreds of years.

Or even thousands years,
quite possibly.

And so, this would be

an unprecedented journey
for humanity.

I just don't know
who would sign up

to live and die
on their way to a new planet.

SHATNER:
How can we ensure
that astronauts will survive

extremely long voyages
across the universe?

Well, one of the methods
that is actually being

seriously discussed
sounds like something

taken right out of
a science fiction movie.

It's referred to as cryosleep.

The idea of cryosleep has
been around in science fiction

for a very long time,

this idea of
an induced hibernation

to allow human passengers
on a spacecraft

to basically sleep for the ride.

If we can bring their metabolism
down low enough,

just to sleep and to rest,

it means, psychologically,
they don't have to spend

many years on a spaceship
slowly traveling through space.

This is kind of an idea
that seems

far-fetched to some people,

but if we look at animals
all around our planet,

we see kinds of examples
of hibernation already.

MASON:
We know it's possible
in a mammalian system

to go into hibernation...

...because bears routinely
do this every winter.

They go hibernate.

We just haven't figured it out
for humans yet,

but it has a lot of promise.

SHATNER:
Could hibernation be
the answer to the problem

of long-distance spaceflight?

It's such a promising solution

that NASA is already
coordinating with a company

called SpaceWorks to develop

a crew module
that will put astronauts into

a deep sleep by gradually
reducing their body temperature.

If this technology
is successful,

it would mean that
the first alien earthlings

would literally snooze their way

to other planets.

PYLE:
The idea is that

one of these spacecraft would be
the size of a small city.

You could have people
in their recliners

in the main deck.

You could have computerized
control systems and so forth.

This idea has been around
for a long time,

and it's something
we think we can do

within the next ten years.

Just imagine what it would
be like to spend months

or even years in a deep sleep

and then suddenly wake up

on another world.

It's a mind-bending thought,

but perhaps the bigger question

is can earthlings
really live on alien planets?

One solution may lie
in new technology

that will allow humans
to breathe

on Mars.

SHATNER:
Scientists at NASA's
Jet Propulsion Laboratory

wait in eager anticipation

as some 127 million miles
away from Earth,

the Perseverance rover

hurtles at more than
12,000 miles per hour

toward the surface
of the planet Mars.

KIRSTEN SIEBACH:
The Perseverance rover

is about the size
of a small SUV,

so it's a pretty big car that
were driving around on Mars.

And we've got cameras
on the end of the rover

so we can look around

and take pictures.

And then have a lot of
scientific instruments

so that we can understand

what Perseverance is
seeing on the surface of Mars.

KAKU:
The Perseverance rover

is scouring
the entire surface of Mars.

Now, why is that important?

And the answer is

all of this is in preparation

for one day putting humans
on the surface of Mars

sometime after 2030.

SHATNER:
Both China and the U.S.
have plans

to send astronauts
to explore the Red Planet

in the next few decades.

Could a successful
mission to Mars

lay the groundwork for building
long-term settlements there,

as many have imagined?

McGEE:
When talking about

future human settlement,

eyes always turn to Mars.

But the Martian environment
right now

is completely inhospitable.

It has almost
no breathable oxygen

and it's ice cold.

These are extremes

the likes of which
no human being could survive.

SHATNER:
If we're to become
alien earthlings,

then we have to find a way
to survive on other worlds.

But how can we protect
future colonists

from the harsh environment
they would endure on Mars

over a long period of time?

One solution may be hiding
in plain sight.

The Mars Express satellite
is conducting

a scan of the planet

when it spots
something remarkable.

It captures detailed
images of strange formations

that look like veins running
across the Martian surface.

Experts believe
that these curious features

are part of a vast network

of underground lava tubes.

ROBERT SCHOCH:
Lava tubes are the result of

volcanic activity
and lava flows.

We know this well 'cause
we can see them on Earth.

So, when a major volcano on Mars

spews out lava,
what happens is that

the lava flows.

And when it flows,

the surface of the lava

cools more quickly
than the interior,

and it forms a crust
and it leaves these tubes.

And these tubes can be huge.

SHATNER:
When NASA analyzed
photos of Martian lava tubes,

they estimated that
these underground caverns

measure up to
1,300 feet in diameter,

wider than most sports stadiums.

This has led many experts to
theorize that living underground

in Martian lava tubes

may be the best way
to efficiently shelter

the first
human colonists on Mars.

SCHOCH:
You can have a tube
that's big enough

in circumference and diameter

to have a house inside.

They can extend
for tens of miles or more.

So, these would be

incredible havens on Mars

for human habitation.

SHATNER:
The possibility of

using lava tubes on Mars

as long-term
living quarters for humans,

has prompted NASA to
conduct a dress rehearsal

here on Earth.

A research station
called HI-SEAS

has been constructed
on Hawaii's big island,

where astronauts train
in natural lava tubes to

prepare for
colonizing off-planet.

LAU:
NASA certainly has had a very
large hand in finding ways

to create colonies or habitats

inside of these places.

That shows us that

using the resources
that are available

locally on Mars, we can build up

the different structures
we would need for a habitat.

SHATNER:
Will the first humans
who travel to Mars

build shelters inside
its massive lava tubes?

Perhaps. But rather than
living underground,

some experts have proposed
a far more ambitious plan

that will radically alter
the Red Planet.

NASA announces they have
successfully conducted

a landmark experiment
on the surface of Mars.

Called MOXIE,
the extraordinary test

utilizes a sophisticated device

to convert small amounts
of carbon dioxide

into breathable oxygen.

MOXIE is this really awesome
test bed package

that we put onto
the Perseverance rover

and sent to Mars.

It's basically
trying to find ways

that future explorers
can produce oxygen

for humans to breathe.

PYLE:
MOXIE is basically a little box

that compresses
Martian atmosphere,

heats it up, runs it past
some kind of catalyst,

and extracts oxygen.

They'd hoped they could
run it maybe five times.

They've run it
many more times than that.

It's been an outrageous success.

LAU:
MOXIE itself is just a demo.

It only produced
a little whiff of oxygen for us.

We definitely have to
enlarge it far more

to allow enough oxygen
for humans to breathe.

But that, by itself,
shows us that we can do it.

And if we can have oxygen
on Mars that we can use,

then that solves a huge problem.

It's inspiring to think that,
in the near future,

we might be able
to not just survive

but actually thrive
on other planets.

But what if we are not

the only ones living there?

What happens when
we come face-to-face

with another civilization
who thinks that

we are the aliens?

SHATNER: As humanity prepares
to send astronauts to Mars

and then, eventually,
to even more distant planets,

it begs the question:

will we encounter alien beings

when we arrive
on these strange new worlds?

And if so, how will we
communicate with them?

LAU:
This question comes up a lot
in astrobiology

and with the public.

How will we talk
to an advanced, intellectual,

alien civilization,
or could we even do that?

And honestly,
the concept is difficult

because we don't know

what aliens are going
to look like,

let alone understanding
the intelligence

of an alien civilization,

and so, we may not be able

to immediately
have a communication.

SHATNER:
Will it be possible
to bridge a communication gap

between earthlings
and extraterrestrials?

It's a question
scientists have been pondering

for over 50 years.

On a rugged mountain slope
stands a complex

of large telescopes known

as the Byurakan
Astrophysical Observatory.

In 1971,
the observatory was the site

of a meeting of the world's
top astronomers, called

"The First
Soviet-American Conference

on Communication with
Extraterrestrial Intelligence."

PYLE:
Carl Sagan, who was a very
prominent scientist at the time,

and Frank Drake,
who started and runs

the Search for
Extraterrestrial Intelligence,

came together
with some other people,

and this was the first really
structured and well-ordered,

rational scientific attempt

at talking about communication

with an extraterrestrial
civilization,

something that up until then

had not been talked about
a whole lot.

SHATNER:
Less than a year
after the conference,

Carl Sagan
and Frank Drake came up

with one potential solution

for how to establish some form

of communication
with extraterrestrials.

They designed
a small aluminum plaque

that was attached
to NASA's Pioneer 10 probe,

and sent into space.

The engravings on the plaque
were a rudimentary first step

towards one day talking
with beings from other worlds.

TEITEL:
On this plaque,

there is a drawing of
an adult man and an adult woman

to kind of show average height.

There's also a picture
of the spacecraft,

and that shows the size
of humans

with respect to the spacecraft.

There is a map
of where you can find the Earth

in the solar system.

The idea being,
if some extraterrestrial life

eventually finds this thing,
they might be able to figure out

a whole lot of information
about us,

including what we look like.

We thought
we would put a message on it

to indicate a little bit
of where we are,

when we are and who we are.

LAU:
Even though aliens might have
a very different form

of communication, perhaps

there could be
some universal patterns

that communication follows

to look for
when we're speaking to aliens.

SHATNER:
The Pioneer plaque
sparked fascination

that, as difficult
as it may seem,

it may actually be possible
for us

to successfully communicate
with extraterrestrials.

But since the 1970s,
the thinking

around this question
has dramatically changed.

Many experts now warn
that when earthlings travel

to alien home worlds,
our first encounter...

might not be friendly.

In our science fiction
or folklore,

it's always the aliens
who come visit us,

and it's about our reaction
to the aliens.

But let's turn the tables.

As we explore outer space,

maybe, just maybe,
we are the aliens.

Maybe we are the ones
encroaching

on other people's backyards.

So, when we make first contact
with an alien species,

I think we should do it
very carefully.

SHATNER:
Is it possible that
when earthlings arrive

on distant planets, aliens will
not welcome us with open arms?

Unfortunately, many astronomers
think the answer could be yes,

including
the late Stephen Hawking,

who famously warned

that extraterrestrials
might look at us the way

we look at bacteria.

KAKU:
If aliens are thousands of years
more advanced than us,

then they could easily
overcome our weapons.

And so,
instead of embracing aliens

from the stars,
we should realize,

"Hey, let's-let's
take a few steps back."

SHATNER:
If we come face-to-face
with extraterrestrials,

will they be hostile?

Or might earthlings
and aliens be able

to peacefully communicate
and coexist?

It's an intriguing mystery,

but for the moment,
the more pressing question

is whether humanity
will choose to dedicate

the vast amount
of resources it will take

to live on other worlds.

SHATNER: Aerospace company
SpaceX launches a crucial test

of its interplanetary rocket,
called Starship.

According to SpaceX's
billionaire CEO Elon Musk,

Starship will help
humanity evolve

beyond our home world.

KAKU:
Elon Musk

has a dream, and his dream
is to create humanity

as a multi-planet species,

and that's why he's building
his own rocket ship,

whose design is
to become the bulwark

of an interplanetary network
of rockets

to go between planets.

SIEBACH:
Collaborations with companies
are really critical

to space exploration,
because private companies

think about
that technology development

in a different way
than NASA does.

And that's really helpful.

PASCAL LEE:
Elon Musk

and Jeff Bezos,
with Blue Origin--

both were inspired
by the Apollo program.

They really took
those directions

in their lives because

they were so inspired by
the possibility of space travel.

And so, if you have somebody
who is single-minded

and running a company
that is possibly able

to get to a place like Mars,

you actually root for that

because it might
actually happen.

SHATNER:
While the involvement

of private companies
is an exciting step

towards living on other worlds,
it doesn't come cheap.

For example, it's estimated

the massive Starship rocket
will cost ten billion dollars

in research and development.

This high price tag
raises the question,

is space exploration
worth such a huge investment?

Experts believe
the answer is yes,

because the fate of humanity

may depend on becoming
a multi-planetary species.

MASON:
A big question is not just

"can we do this"
but "should we do it?"

And I think that
we really have no choice.

Becoming multi-planetary
gives us the first sort of

backup plan for humanity.

So, if something
goes horrifically wrong,

or an asteroid hits,

we become the stewards of life
and enable it

to live on more than one planet.

SHATNER:
With all the time,

money and effort being invested

in next-generation
space programs,

it makes you wonder
what milestones

will we reach in this century

and the next?

TEITEL:
Humans have this

insatiable need to explore,

to push the limits
of what we can do,

of what we can survive.

And that's really
what kind of got people

wanting to go into space
in the first place.

And today, it's not limited
to the U.S. government

and these private companies.

We're seeing
other countries also have

these deep space missions.

And now, everybody wants
to be involved in space somehow.

SIEBACH:
This is such an exciting time

to be a part
of space exploration.

There are more groups
working on this

than there have
ever been before.

All of these developments
are absolutely thrilling,

and that's clearly motivating

a lot of people right now.

MASON:
I believe humans inevitably

will be on multiple planets,

that we have this in our nature,

we have the capability,
we have the technology.

It's really just a question
of willpower and time.

We have to consider using
all the tools and technologies

at our disposal,
but we won't know until we try.

Daring to venture
into the universe is perhaps

the single greatest endeavor
in human history.

Thus far,
the progress we've made

exploring the final frontier
is truly inspiring.

Do we have the right stuff
to reach distant planets

and become alien earthlings?

Well, let's hope so.
But for now,

the answer remains

unexplained.

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