All language subtitles for Engineering.Evolved.S01E05.1080p.AMZN.WEB-DL.DDP5.1.H.264-BurCyg_track3_[eng]

[dramatic orchestral music]

- [Andrew] Since the
invention of the wheel,

humans have pushed the
boundaries and possibilities

to go faster, higher, and
deeper than ever before.

The engineering evolution of
cars, ships, planes, trains,

submersibles, and rockets
has been a monumental journey

of inspiration, innovation,
sometimes failure, and success.

[group cheers]
So how did we get to

where we are now, and
where are we going next?

[orchestral music continues]
[images swoosh]

[text thunders]

[upbeat music]

We are living in an
age where space travel

is no longer limited
to brave astronauts

and national programs.

Some of the world's
most powerful rockets

come from private companies,

and every day, civilians
have the opportunity

to take a ride, for the
right price, of course.

- We couldn't get 10 feet
off the ground 100 years ago,

and now, we've got spaceships

that are 10 billion
kilometers away.

- From the first Apollo missions

in the late 1960s to the 2020s,

only 12 people in human history

have ever stepped on any
moon or planet beyond Earth.

However, that very exclusive
list could be about to expand.

- We are in the era
of space tourism,

where civilians,
untrained people

get to actually witness
the view from space.

It's really incredible.

- [Narrator] Fueled
by better propellants,

more engines, and
greater technology,

space programs have trips
to Mars within their sights.

- But maybe in the future,

I'm getting on a
two-day space flight

to go see my family on Mars.

That sounds quite
attractive, doesn't it?

- [Narrator] The dangers
of achieving liftoff

are not to be taken lightly.

- Every step along the
way there's still things

that can go devastatingly wrong.

- [Narrator] But the rewards
are out of this world.

The results of such lofty
projects have the ability

to change everything from
improving earthbound travel,

unlocking new resources
that could power

the cities of tomorrow,
to building a future

for humankind among the stars.

[text rumbles]
[gentle orchestral music]

One of the most exciting
spacecraft of today

is the Boeing CST-100 Starliner.

- Go Starliner.
- All systems

are go for liftoff.

- The Starliner is
capsule-like and designed

to go to the International
Space Station

and return back to solid ground.

- Once the Starliner
and its crew manifest

have finished with
their mission,

it will undock
itself autonomously

and then descend down,
back to the planet,

all pre-programmed.

It will be equipped
with solar panels,

such that it could
essentially, self-power

its descent back
down to the ground.

We want to be able to
reduce our footprint

and so the Starliner
will be able to be

reused up to 10 times.

- It's a real design
challenge to be able to have

the Starliner capsule survive

for up to 10 different missions.

One of the biggest
challenges is reentry.

When the capsule is reentering,

there's a tremendous
amount of heat

that is a result of the
friction between the air

and the outside of the capsule.

To be able to do this 10 times

means they need a
really robust design.

It needs to be able to handle

huge heating and cooling cycles,

and it's pretty incredible

that they've designed
it to do that.

- [Narrator] In 2022,
Boeing and NASA completed

their crucial uncrewed mission

to the International
Space Station.

The final test
flight in preparation

for the astronauts'
first crewed flight,

an Atlas V rocket, blasted
the Starliner into orbit.

Using a series of
sensors, the capsule

autonomously guides itself

into an open docking port
at the Space Station.

While in flight, the
Starliner harnesses

solar energy to generate power.

Boasting more than
3,500 solar cells,

this spacecraft
creates approximately

2,900 megawatts of electricity.

Starliner will bring the
first crew rotation mission

to the International
Space Station, as
early as summer 2024.

The first ISS component
was launched in 1998,

with the long-term residents
arriving in the year 2000.

Since then, over 250
astronauts, cosmonauts,

and space tourists, have visited

from over 20 different nations.

Maintaining and
checking equipment,

conducting science experiments,

and installing solar
panels are just a few

of the critical tasks performed

by the long-term ISS residents.

While life at the ISS may
seem pretty isolating,

residents are known
for playing pranks

on their fellow astronauts.

Astronaut Scott Kelly,
played one of the most

outlandish pranks in
space in February, 2016,

donning a gorilla suit

and chasing Astronaut Tim
Peake, around the ISS.

Other astronauts have
shockingly, emerged
from cargo bags

and even snuck in a
corned beef sandwich.

Before the concept
of visiting space

was even a remote possibility,

the physics behind the
world's earliest rockets

needed to take off.

- When we think about
rockets and going to space,

we're really talking about
a controlled explosion.

The amount of energy
that's required to move

mass into space is almost
beyond human imagination.

- The shape of rockets is
usually pretty consistent,

they're long and
they are pointy,

and this helps cut through
the air in our atmosphere.

- When a rocket is going up,

it's being pulled by
the gravity of the Earth

and the more the
weight, more the pull.

Secondly, air is
dense, closer to Earth,

and it gets lighter and lighter
and lighter as it goes up.

So the resistance
this rocket faces,

is significantly
less as it goes up,

force of gravity reduces.

And the drag forces also reduces

because you are going
through thinner atmospheres.

[fireworks whines and booms]
- [Narrator] The first use

of rockets dates back
to the 11th century

when the Chinese and
Mongols were at war.

During the Siege of Kaifeng,

the Chinese staved off
the Mongolian invaders

using a swarm of fire arrows,

a simple form of
solid-propellant rocket.

- When we look back at
antiquity, at rockets,

we think of the early
Chinese rockets.

These were chemical
rockets basically,

if you take sulfur,
charcoal and saltpeter,

and mix those materials
together and ignite them,

you have gunpowder.

If you take that gunpowder
and put it inside a tube,

like a shaft of bamboo, all
of a sudden you have a rocket.

- [Narrator] The use
of similar rockets

spread all the way to
Europe and the Middle East,

where they were used
for both military

and ceremonial
purposes as fireworks.

Today, NASA's spectacular
Space Launch System

holds the record for
most powerful rocket

to ever be
successfully launched.

- NASA has developed
the SLS rockets,

or Space Launch System rockets,

and these are being used
on the Artemis mission,

which is going to be used
for travel to the moon,

and soon after, Mars.

NASA's SLS rocket can produce

8.8 million pounds of
thrust, which is 15% greater

than the previous record
holder, the Saturn V rocket.

- NASA's vision is to go
back to the moon and to Mars.

To get there, we need spacecraft
that are relatively large.

We need to support a number
of humans to go to the moon

for weeks or months at a time,

and to go to Mars,
years at a time.

So this means we're moving

much larger masses
to space to do this.

To that end, we
need a huge rocket.

The SLS is powered by liquid
hydrogen and liquid oxygen.

Hydrogen is an
extremely powerful fuel.

It's very low density, and
that's what we're looking for.

We want for our rockets to have

the maximum amount of
energy for any given mass.

So if your fuel's heavy,

but it gives a lot of
thrust, that's okay.

But if you have a
really powerful fuel
that's really light,

it's even better because
you don't have to accelerate

all of that mass upward
while you're moving.

- [Narrator] Engineers
are looking for
greener ways forward,

and hydrogen is
showing real potential

as the rocket fuel
of the future.

- Hydrogen can be
obtained sustainably

by using solar power
to break down water.

- One of the great
things about using

a liquid hydrogen fuel source,

rather than a
kerosene fuel source,

is the benefit it has
to the environment.

You're not burning off,
like a traditional fuel

that leads to
typical hydrocarbons.

When you do your controlled
burn with a liquid hydrogen,

the byproducts are actually
mostly water vapor.

- [Narrator] Liquid
hydrogen has its benefits,

but dealing with one of
the lightest elements

in the universe comes with
its own set of hurdles.

- I mean, hydrogen's
a promising fuel

but it's very
difficult to work with,

it's the smallest
element that we know of.

And when you think of
all atoms in space,

whether they're
iron or hydrogen,

they're just these
little tiny balls.

And if hydrogen is much smaller

than the steel tank that
is holding the hydrogen,

the hydrogen can actually
make its way through

in between the iron molecules
and escape the tank.

So hydrogen leakage
out of the containers

that we've built for hydrogen
storage is a big issue.

- One of the challenges of
carrying liquid hydrogen

is that it needs to be stored

at negative 253 degrees Celsius,

anything above that, and
it starts to evaporate.

So this requires a pretty
complicated cooling system

that needs to be
stored on the rocket.

And if it starts to evaporate,
you could be in space,

literally just losing fuel,

leaving you with not
enough fuel to return.

- And the other problem
is if hydrogen does leak,

it's explosive.

- [Andrew] Early examples of
this were during the 1930s,

when airships
powered by hydrogen

seemed to be the future of
flight, until disaster struck

in one of the most
infamous catastrophes.

- You take the
Hindenburg example,

you've got a large volume
of concentrated hydrogen.

That hydrogen is
leaking out into the air

and all you need is a small
ignition and it goes off.

- [Narrator] Centuries before
NASA was reaching for the

stars, the pioneers of rocketry
were struggling to solve

one of space exploration's
biggest problems,

how to break through the forces

of Earth's gravitational field.

Born in 1857, Russian
rocket scientist,

Konstantin Tsiolkovsky,
devised a device and equation

that became a fundamental
principle of rocket science.

He had been captivated
by reading books

such as "From the
Earth to the Moon,"

and "Journey to the
Center of the Earth,"

by early science fiction
writer, Jules Verne.

- Konstantin Tsiolkovsky
was originally inspired

by the works of Jules Verne.

So we think about science
fiction actually leading to

kind of this wondrous
inspiration that has taken us

to the depths of space
exploration that we're at today.

He had two major contributions

to the field of rocket science,

the first of which, being the
calculation of trajectories.

So he developed
the math necessary

for launching a
rocket and determining

where it was going to end up.

This was crucial
to space travel.

And the second development
was the concept

of multi-stage rockets, and
that's where the rockets

are essentially,
shedding their own mass,

the further up they go.

So it ends up taking less
weight and less energy,

the higher up you go.

- Tsiolkovsky's equation
kind of deals with

this idea of the
moment of launch

is kind of the most
critical piece,

in terms of getting
a rocket to space

because at that
particular point,

it's at its heaviest
and has the most mass,

and you need to figure out
a way to counteract that

to get enough thrust to get out.

- [Narrator] To perform
a successful launch,

rockets must produce a
greater amount of thrust

than their weight.

The heavier the rocket,

the more thrust is
needed to blast off.

Weighing in at 330 tons,

NASA's stage two, Atlas
V-541 rocket produces

3.8 million newtons of
thrust at full throttle.

As one of the world's
biggest rockets,

this colossus launched the
Mars Perseverance rover

into action at Cape
Canaveral in July 2020,

kick-starting
interplanetary flights.

Perseverance has been roaming
the red planet since 2021,

searching for signs of
past life and helping NASA

to prepare for future
human exploration.

This epic launch would
never have been possible

without American rocketry
pioneer, Robert H. Goddard.

Through his cutting-edge
experiments,

Goddard developed many
of the basic principles

of rocket science, including
the use of fins for stability,

the need for a
pump to force fuel

into the combustion chamber,

and the concept of
a rocket nozzle.

- So we can use rocket
fins to physically

steer the rocket as it
pushes itself off the air,

but that only works up
until a certain point.

Eventually, once we
surpass the atmosphere,

there's not much
air to push off of

and they become pretty useless.

But they're very good
inside of our atmosphere

to control the rocket.

- [Narrator] As
a rocket ascends,

the thrust direction may shift,

causing the rocket
to veer off course.

To ensure the rocket
stays on its flight path,

we need something to help steer
when there is no atmosphere.

- Once in space, the
way that engineers

and scientists have
found to control rockets

is through mechanical
instruments that
are called gimbals,

and these are effectively
articulating arms

that upon swinging them,
could help you direct

and steer the rocket as
it's flying through space.

- [Narrator] The
original gimbal design

has been modified
to match the power

of new rocket engines with
incredible capabilities.

Private aerospace company
SpaceX, is pushing boundaries

with their Raptor 2 engine,

which produces over
230 tons of thrust.

Raptor 2's gimbaling range
is extremely impressive,

15 degrees on the Y and Z axis,

which makes it ideal
for specialized

flip and burn
spacecraft landings.

SpaceX has big plans
for the Raptor 2,

powering dreams of
future space exploration.

Between the early days
of Goddard's experiments

and the sophisticated
rockets of today,

a major development in
their technology came

when these powerful
machines weren't used

as a vehicle for exploration,
but tools of war.

- So in the Second World
War, we see the introduction

of long-range
ballistic missiles.

So these are, you know,
still earthbound rockets,

but able to cover
a great distance.

They're not guided,
you can kind of send it

on a particular trajectory,

you want it to go
to a certain place,

but ultimately, you
can't really pinpoint

exactly where this bomb
is going to strike.

- [Narrator] During World War
II, the development of rockets

became top priority
for Nazi Germany.

V-2 rockets were capable of
traveling at supersonic speeds

with such extreme arcs, with
no warning for those below,

making them impossible
to defend against.

Over 3,000 V-2s were
dropped during World War II,

resulting in the deaths
of an estimated 9,000

civilians and
military personnel.

- The V-2 was really a
huge change in technology.

It was man's first step

in really being able
to go into space.

While there were
solid fuel rockets

that came before it, solid
fuel isn't controllable.

You can't turn it off and on.

Once you put the match
to it, it's gone.

With the V-2, you suddenly
have a controllable system.

You can control the
rate of fuel flow,

you can control the
amount of thrust

that you get from this vehicle.

So we're taking the
first baby steps

towards modern rocketry.

Post-World War II,
we see the advent

of the intercontinental
ballistic missile.

Basically, we can send missiles

in suborbital trajectories
and deposit payloads

on the other side of the world.

The Russians, after
developing ICBMs,

realized that space was
somewhere they could reach.

To that end, they
launched Sputnik.

Sputnik was the first
manmade satellite of Earth.

Basically, we were
able to launch

a very small object into
space that was able to send

a radio signal back
to Earth to show

that it was in orbit, that
it was going around Earth.

It's really a huge milestone.

Everything before
that was essentially,

still bound to the Earth's
gravitational field.

We now, are able to put
something into space

and keep it there.

The US sees the Russians
taking these steps

and says we have to match,
and we have the space race,

and that starts the
Mercury astronaut program.

We're basically gonna try
and send people into space.

- [Narrator] After experiments,
sending animals into space,

including fruit flies,
dogs, and chimpanzees,

the first humans arrived
in space in 1961;

Russian cosmonaut, Yuri Gagarin,

and American astronaut,
Alan Shepard.

The first space race was
a race for national pride,

country versus country.

Today the landscape
looks much different,

it's become a billionaires game.

- Now, private companies
in the same country

are competing against each other

in terms of sending satellites.

So it is a little bit of
change and it's probably

because of the different
needs we have these days,

comparison to a few decades ago.

- And so as with anything,
competition hopefully,

makes things cheaper, but
competition hopefully,

also leads to ingenuity.

- [Narrator] In March, 2002,
billionaire business mogul,

Elon Musk, founded
SpaceX with the aim

of revolutionizing
the space industry.

Otherwise known as

Space Exploration
Technologies Corporation,

this startup rocked the
world with the launch

of its first Falcon
Heavy rocket.

The Falcon Heavy's
Merlin engines use RP-1,

a highly refined form of
kerosene and liquid oxygen

as propellants in a gas
generator power cycle.

Chemical propulsion
engines and rockets work

by mixing two chemicals,
fuel and oxidizer,

in a combination chamber to
create a violent reaction.

Despite how far this
technology has evolved,

companies today, are still
using the same principles

of chemical propulsion
that were used

to fuel Goddard's tests and
the space race decades ago.

- The Falcon Heavy
was a really important

proof of concept for
showing that we could take

something really massive and
still propel it into space.

- The Falcon Heavy is the
second most powerful rocket

in operation right
now, just behind

the Space Launch
System for NASA.

The Falcon Heavy opens
up a whole lot of doors,

in terms of what you can do.

So if you have, you know,
your regular Falcon 9 rocket,

and that will allow you
to get a certain payload

into Earth's orbit,
you know, that's great.

But you need a much bigger,
a much heavier rocket

to be able to get beyond that.

- [Narrator] Another
reason why the Falcon Heavy

is such a major player in the
space exploration industry

is the low cost per launch.

A Falcon Heavy launch
runs 97 million USD.

In contrast, NASA's
Space Launch System

is expected to cost 4.1 billion.

Though NASA's SLS is taller

and has a slightly
larger payload,

the difference in the price
tag is out of this world.

The modern space race is
motivated by private companies

with their eyes on the future

of turning space transportation
into a thriving business,

and it's given us
a lot of progress

in a short amount of time.

While it's one thing to
successfully launch rockets

carrying cargo and supplies,

launching humans
safely into space

is a whole other ballgame,

since who goes up
needs to come down.

As rockets descend
through the atmosphere,

they're forced to contend
with increasingly dense air.

As they collide with the rocket,

air molecules are
compressed and heated,

generating friction and
heating up the vehicle surface.

The faster the rocket
descends, the hotter it gets,

a major challenge
that could result

in structural damage and
critical systems failure.

- The angle of
reentry is critical.

If you come in too shallow,

you end up skipping
across the atmosphere

like a pebble in a pond.

If you come in too deep,

you're not slowing
yourself down enough

to not explode in a big
fiery ball upon reentry.

- So when we look at
how capsules come back

into the atmosphere,
they're coming back

with their largest surface
area facing the atmosphere.

The upper parts of the Earth's
atmosphere are very thin,

there isn't a lot of atoms
there to interact with.

But we want to interact with
as many of them as possible

because they're what's gonna
slow down our spacecraft.

So having that big, blunt
area with an ablative material

that's really resistant to heat,

allows us to use the
friction in the atmosphere

to slow us down, to get us
below those orbital velocities.

So when we get down into
the deeper, thicker parts

of the atmosphere, we don't
have all of that kinetic energy,

all of that speed.

Traditionally, when
we've built capsules,

we've used ablative materials.

Basically, these are materials
that when exposed to heat,

break up and expose
more material below it,

so they're kind of
semi-sacrificial.

We lose a bit of
the first few layers

to protect the inner layers.

So that ablative coating or
that ablative heat shield

gets consumed during
the descent to Earth.

- What a heat shield
does is it essentially,

takes the brunt of all
that stress and strain

and that heat that the
craft is experiencing,

such that it doesn't
travel through

the rest of the rocket.

And some of the
materials that can handle

such high heat, we have to
start off with ceramics.

- And when you have
a ceramic plate

and you put something hot,

the bottom doesn't
get hot so fast

because ceramic
doesn't conduct heat

as much as a metal plate
does, or a metal container.

So they can resist heat a lot,

and ceramic can be customized
shapes to deflect heat.

So when you are
coming down this drag

it's heating this
from the friction,

and the outside's solid;
if it doesn't move the heat

to the other parts,
you're okay on the inside.

- [Narrator] Rockets, like
the SpaceX Dragon spacecraft,

use a PICA-X heat shield for
its thermal protective system.

PICA stands for Phenolic
Impregnated Carbon Ablator,

a special material
capable of withstanding

higher temperatures and
providing better insulation.

The Dragon also uses thermal
blankets and control coatings

to ensure its components
remain at safe temperatures,

protecting the vehicle
and its passengers.

Today's missions would
not have been possible

without NASA's Gemini
program, created in 1961.

- The Gemini program was
conceived when NASA officials

realized that there
really needed to be like,

an intermediate step
between Project Mercury,

which the stated goal
was just to, you know,

get a man into space, and
then the Apollo program,

which is putting
people on the moon.

And there are a lot of
steps that needed to happen

in between those two things,

and the Gemini program kind
of fits squarely in that.

- They experienced
the first spacewalk,

the first docking in the space,

and the first recovery of
a spacecraft in the sea.

- The computer science
part of it was tricky

because computers in
the day, were large

and you couldn't put
them on the vessel.

So you actually needed
to have a lot of the work

happening on the ground,

and then that transmitted
up into space.

- Landing a spacecraft
is extremely hard,

especially, one like Gemini,
where it's not a rocket

that you can easily steer.

So we came up with this
idea that we can just

launch this into the sea.

And so we learned how
to quickly get to it

and how to quickly
get the occupants out.

- [Narrator] The Gemini
spacecraft boasted

a revolutionary
reentry control system,

rendezvous, and
docking capabilities,

as well as improved
life support,

allowing for longer
stays in orbit.

- The Gemini space
program was instrumental

in proving that we could
have prolonged stays

for human crews in space.

- So whenever you launch
a human into space,

you have to take their
entire living environment

along with them.

All the infrastructure
that we take for granted

here on Earth, has to be
provided artificially in space.

- [Narrator] The Gemini
missions paved the way

for future complex
missions to space

and new players are hoping
to get into the game.

The shifting regulations
around space travel

have opened up possibilities
for countries like Canada,

which previously
relied on other nations

for their orbital space flights.

Today, only the
United States, Russia,

and China, have launched
humans into space,

but more countries are planning

to add their names to the list.

In 2023, Canada
announced a new plan

to support privately built
rocket launches in the country

as global demand for
space-based services grows.

India is hoping to be
the next big player,

using the recently upgraded
Satish Dhawan Space Center

for their rocket launches.

Originally built
in 1979, the SDSC

got a second launchpad in 2005,

allowing multiple
launches in a single year.

With the design of the Gaganyaan
crewed orbital spacecraft,

India could be sending three
people into Earth's low orbit

for up to seven days in
the not too distant future.

But another country
has their sights set

far beyond Earth's low orbit.

US-based NASA has completely
overhauled its older systems

to support future reentry
after trips to the moon,

and one day, Mars, in
their Orion capsule.

- NASA's Orion spacecraft
is the newest generation

of reentry vehicles designed
for today's space travel.

It's built to
withstand temperatures

of 1,700 degrees Celsius,

and speeds in excess of
40,000 kilometers per hour.

- The Orion space vehicle
is really designed

to get us to the moon and Mars,

but it still has to come back
through Earth's atmosphere,

so it still needs
the same systems that
older capsules have.

But what we've done is
made it more robust.

We have better heat shields,

we have better
ablative materials.

We also now, have
automated systems

to control the trajectory
and attitude of the capsule

so that it's hitting
the Earth's atmosphere

at precisely the right
angle to minimize

the amount of heat generated.

- So we've already
sent machines to Mars,

that are now
roaming the surface.

So we could say for
example, that Mars

is the only planet that
is controlled by robots,

or that is entirely
inhabited by robots.

And so we know that
there is a way,

in terms of propulsion,
to get there.

The primary bottleneck
is how humans

would survive such a journey.

- And that matters
because if we ever

want to have a chance
of exploring space,

we need to bring ourselves
the food that we'll need

and all the resources we'll need

to do that space
exploration safely

and come back to Earth.

And if it takes
months to get to Mars,

we will physically
need the resources

to survive for all those months,

not just the equipment or
gear of the rocket ship.

- [Narrator] China is
also making strides

in the reusable rocket sector.

In 2022, engineers
at the Chinese

Aerospace Science and
Technology Corporation

perform their first tests on
their 130 ton thrust engines,

the YF-100N.

These engines will be used
in the next generation

of launch vehicles, including
a new reusable rocket

for launching a crew to the
new Tiangong space station,

and eventually, the moon.

Plans for the first test flights

will begin as soon as 2026.

Much of today's excitement
in space exploration

stems from the
original lunar mission.

In the early 1960s, American
president, John F. Kennedy,

threw down the gauntlet
to get us to 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.

- [Narrator] The
Apollo 11 spacecraft

was made of three components,

the command module, service
module, and the lunar module.

- The actual launch vehicle
itself is three stages,

and when this vehicle
actually launches,

it can barely get
off the launchpad.

Then as it starts
going, it burns fuel

at an immense rate and we
actually drop the weight

of that first stage off,
and go to a second stage,

and that continues to
accelerate this rocket.

And then we drop
that second stage off

and fire a third stage and we're
finally getting into orbit.

- The Apollo
spacecraft was made up

of three different components.

First, we had the
command center,

which was the living
quarters for the crew,

and then we had the lunar
module and the service module.

The importance of the
Apollo 11 mission,

and actually landing humans
on the moon was immeasurable.

The inspiration
that this led to,

countless people,
future generations,

we're still building
off of this momentum

in today's space travel.

- The command module is
where all the controls are,

and the most part, the living
space for three astronauts.

The service module is where
you will find the engines,

and then there was
a lunar lander.

And so in the rocket, the
three of them are stacked.

Once they reach
our Earth's orbit,

the command module
and service module

need to separate from
the lunar module.

The lunar module is
then flipped around,

and then they unite.

Once they get to the
moon, the lunar lander

then detaches from
the command module

and proceeds to
land on the moon.

- [Narrator] During the
lunar module's final descent

an automatic landing
system guided

Apollo 11 astronauts
towards the moon,

before Neil Armstrong
took manual control,

piloting the module, using
four clusters of rockets

to finally touch down.

Four hours later, Armstrong
would say the words

that changed the world.

- [Neil] That's one
small step for man,

one giant leap for mankind.

- [Narrator] For Apollo
11's return flight,

the module was propelled
back into lunar orbit

by its ascent stage
rocket engine.

After it rendezvoused and
docked with the command module,

the lunar module was jettisoned.

Right before reentry into
the Earth's atmosphere

the service module separated
from the command module,

left to burn up
in the atmosphere.

Building on this success,
NASA went on to complete

six Apollo missions, landing
a total of 12 astronauts

on the moon, between
1969 and 1972.

After the Apollo missions,

lunar exploration lay
dormant for several decades.

Today, NASA's Artemis program
is grabbing the attention

of people everywhere,
promising to return astronauts

to the moon by 2024.

This modern-day moon
landing will set the stage

for a human mission to Mars,

200 times further than the moon

at the closest
approach to Earth.

Engineers and
innovators are looking

to cutting-edge technology
to reach this new frontier.

- One potential
development for rocket fuel

is nuclear thermal propulsion.

What's really cool about
this is it would use

nuclear power to
use hydrogen still,

but have it be a much more
energetic and violent reaction.

So that would basically
mean we're getting

even more fuel efficiency
out of hydrogen fuel.

- You wouldn't use
nuclear thermal propulsion

for the actual launch, but
the upper stage you could.

It would be much more practical

for getting between
space destinations.

- Nuclear presents a really
interesting opportunity

for space travel because
we're always going to be

working against needing to take

a large number of
resources to be able to get

even further into space.

So nuclear, allowing
for hydrogen as a fuel

to be even more efficient,
means that with nuclear

we can get further on
the same amount of fuel.

- We've already found
ways to use nuclear

as a propulsion system on
Earth, and that is submarines.

And so perhaps there's a lot
that engineers and scientists

don't necessarily
need to relearn,

but that they could borrow
from having designed

those type of systems.

- It's not to say it's
not a challenging feat

to put a nuclear
reactor up in space

where it'll be exposed to
the massive forces of launch,

the G forces and the shocks
that are gonna come with it.

- [Narrator] In January,
2023, NASA announced

a collaboration with DARPA,

the Defense Advanced
Research Projects Agency,

to demonstrate a nuclear
thermal rocket engine in space

by 2027, a critical step
towards crewed missions to Mars.

With nuclear thermal propulsion,

getting to Mars could take
as little as two months

instead of nine,

but the idea of using
nuclear propulsion power

isn't entirely new.

NASA and the Soviet space
program spent decades

researching nuclear propulsion
during the space race.

Despite some promising results,

nuclear propulsion systems
didn't really take off.

There were many safety concerns

around the application
of nuclear power,

especially after the Cold War.

But the growing
environmental concerns

of the 21st century
have aerospace engineers

looking to reignite
nuclear research

in hopes of finding more
sustainable solutions.

The key to space travel is
finding the right balance

between power and safety.

The possibility of
creating stronger engines

capable of further
and faster voyages

needs to be weighed against
the potential dangers

to the vehicle, passengers,
and the environment.

While some teams are
devising the next generation

of green propulsion,
others are focused on

how they can cut
costs and pollutants

by simply reusing what
they already have.

- After the Apollo mission,

NASA realized that launching
vehicles into space

was extremely costly.

At the time, the Apollo mission

was the most expensive thing
ever undertaken by mankind.

- Reusable rockets present
a really important solution

to minimizing the negative
environmental effects

that we have in space.

So imagine you're trying to
take a trip across the country

and you drive your car there.

Once you get to
your destination,

imagine taking your car
and just throwing it away.

That's gonna be terrible
for the environment

and it's gonna be
very expensive to you.

- You know, we would do a
lot of precision machining

to build these
propulsion systems

and then we would just one
time, use them up in space

and leave them there.

- Another potential
environmental impact

is what the amount
of space debris

that we are leaving in space,

is going to have an
effect on, in the future.

There's a large field of debris

from old pieces of equipment,
obsolete satellites,

that are, over time,
only gonna pose

a greater and
greater threat to us

trying to launch a
rocket through them.

- And that's where the idea

for the Space Shuttle comes up.

Let's try and make
something that's reusable,

that we don't have
to build a new one

every time we want
to launch into space.

We basically have our
reusable space plane

attached to a large fuel tank
and solid rocket boosters.

- Getting the Space
Shuttle up into space,

you strap it to the
side of a rocket,

and it's the rocket
that goes up into space

and the Space Shuttle, at
that point, is just baggage.

The Space Shuttle functionality

is all designed
around what's required

to safely bring it
back down, so reentry.

You need to get it, first of
all, through the deceleration

that occurs during
reentry, safely.

And then you need
to have sufficient

amount of maneuverability
to be able to land

as a glider would.

- [Narrator] But high
operational costs

and major safety concerns
following the tragic

Challenger and Columbia
shuttle disasters,

led to the Space Shuttle
program's retirement.

- The Space Shuttle
was really envisioned

to be a low-cost system.

In essence, it never
ended up achieving that.

- The cost of maintenance was
something they didn't expect

because when the Space
Shuttle went back,

there was a lot of damages
and the maintenance

was really expensive.

- It also had a
number of failures.

Obviously, the system
was very complex.

To work correctly, everything
had to go perfectly,

and what we saw is when
even small things go wrong,

we can have disasters.

- [Narrator] In 1986,
seven crew members died

on the Space Shuttle Challenger.

During a routine mission,
just 73 seconds into flight,

the failure of one of
the solid rocket boosters

led to a rapid destruction
of the entire shuttle.

Tragedy struck again in 2003,

when the Space Shuttle Columbia,

broke apart upon reentry
into the Earth's atmosphere,

killing all seven
crew members on board.

The Challenger and
Columbia disasters

were a major tragedy that had
a profound impact on NASA,

the space program, and
the entire country.

In the aftermath
of these disasters,

NASA worked to improve
the safety of the shuttle,

but it soon became clear that
future galactic explorations

would need a brand
new spacecraft.

- Since the end of the Space
Shuttle program in 2011,

NASA has relied
on Russian rockets

to take American
astronauts to the ISS.

- The Space Shuttle program
really was a wonderful idea.

It did provide a huge amount
of science and understanding

for mankind, but it was
costly, and we needed a change.

And that's why NASA
decided to move away

from the Space Shuttle
program, to other programs.

- [Narrator] If it
weren't for the interest

and investment of
private companies,

the era of reusable
rockets might have ended

right then and there.

But only one decade later,
we have multiple companies

possessing their
own reusable rockets

in a new era of
competition and creativity.

- Primary use of
space at the moment

is communications technology.

And there's been a
significant shift

from having small numbers
of stationary satellites,

stationary in the
sense that they hover

over one location in space
as the Earth rotates.

They have to be out at
relatively large distances

from the surface of the Earth,

to the concept of
having many, many more

smaller communication satellites

in low Earth orbit
that then rotate around

and they're constantly
changing their position,

relative to the
surface of the Earth.

So that leads you to launch
a lot of these things,

and so you need to
have reusable rockets

in order to be able
to make that process

effective and efficient.

- If we can reuse a $60 million
launch vehicle 10 times,

instead of that launch cost
of disposing of the rocket

being $60 million every launch,

we're down to a $6 million cost.

And all of a sudden the
cost to send satellites

or people in the
space comes way down.

- [Narrator] The first company
to bring reusable rockets

back to the
forefront was SpaceX.

When SpaceX was founded in 2002,

it promised reusability,
lower launch costs,

and easier access to space.

This was the first
time in history

that a reusable rocket
had returned to Earth

and was recovered intact.

In 2017, the same Falcon
9 Rocket was reused

and successfully launched.

- SpaceX sort of
questioned this concept

of disposable rockets,
and they said,

hey, if we could
just figure out a way

to recover those rockets,
the ones that we spend

so much time and energy
building down on Earth,

and bring them back
down and reuse them,

we'd save all that
additional cost

of machining and engineering.

The SpaceX promise to the world,

that they'd be able
to massively cut down

the costs of space travel.

- There's a lot of failures,
of course, we expect

in such projects, but
finally when you see,

for example, SpaceX could
successfully land a rocket,

it's a really exciting
moment for everyone to see.

- I think the first
time that you see

the stage it's gonna
land on the barge,

it just looks so improbable.

- Some of the important
design elements

of the Falcon 9 rocket are
that it actually reserves

a little bit of fuel
for its own thrusters,

that it can then use
to control its descent.

- The other way that
they accomplish this feat

is by having a few
heat-resistant fins

that help with the
steering of the rockets

as it descends.

- And then once it's going to
interact with the landing pad

it has four shock
absorptive legs

that help minimize that
final push toward the Earth.

- [Andrew] SpaceX
began expanding

its reusable rocket fleet
to include the much larger

Falcon Heavy and reusable
Dragon spacecraft

for missions to the
International Space Station.

- SpaceX was the first one
to take American astronauts

back to the ISS,
from American soil,

and that happened in 2020.

We're coming up to
almost six crews,

delivered to the ISS
by Dragon spacecraft.

- [Andrew] NASA has
calculated that commercial

launch costs to the
International Space Station

have been reduced
by a factor of four

over the last 20 years.

- When we look at
space, historically,

the cost of mankind
going to space

have been literally,
astronomical.

In the last decade, we've seen

a revolutionary
change in rocketry.

The cost to launch vehicles
to space has come down,

in orders of magnitude,
we can now launch

very small satellites
which provide

huge amounts of information,
at really low costs.

It's bringing the technology
of space to the average person.

There's companies who
are sending up fleets

of hundreds of tiny cube sats,

to take pictures of
the world every day.

These small satellites provide
farmers with the ability

to see if there's a
part of their field

that's experiencing
drought or blight,

or help engineers determine
if the slope of a mountain

is becoming unstable and
a landslide's likely.

So it's really making
space accessible

for even small and
medium sized companies.

It is not a huge cost
to go to space anymore.

- [Narrator] As costs
of rocket launches

are drastically
reduced, this increases

the potential for
civilian access to space,

ushering a new era
of celestial tourism.

Predictions that space
tourism could become

a multi-billion dollar
industry within the next decade

have spurred on a sequel

to the space race
of the 20th century.

Except now, the contenders
are private companies

seeking to send civilians
out of Earth's atmosphere.

One of the biggest
competitors is Blue Origin,

a company focused on
suborbital space tourism.

Owned and founded by
Amazon founder, Jeff Bezos,

their first reusable
rocket, the New Shepherd,

launched and landed in 2015,

and had its successful
reuse occur in 2016.

- Historically, we've
seen a few space tourists

go into space.

The first ones would go up
on the progress modules,

with the Russians, to the
International Space Station.

More recently, we've
seen New Shepherd,

and New Shepherd is
one of the vehicles

that's able to get
the people to space

for a relatively
short period of time.

This launch vehicle
takes people up

for a suborbital trip to space.

So basically, this
takes you up into space.

You get a few minutes in
space to enjoy weightlessness,

see space outside of
our atmosphere, and
then return back.

But it's a little bit different
than other space systems

that have taken people to space

because this vehicle's reusable
and it lands vertically.

- [Narrator] SpaceX's
Starship, is the next evolution

in space launch systems.

If it is successful,
the Starship

could do for space tourism,
what the Falcon 9 did

for reusable rockets.

This could be the first
large-scale, reusable,

commercial rocket,
taking droves of tourists

to space and back.

In the future, a trip to
space may be as common

as a tropical vacation.

However, before we can rush out

and book our holiday
amongst the stars,

it will be important to have
access to fuel in space.

Asteroid mining could
offer such a solution.

- The biggest thing
keeping mankind

from being successful in space

is the amount of energy it takes

to get things into orbit.

So right now, we have
to have a huge rocket

to get mass into space,
to build a space station

or to go to Mars,
or go to the moon.

But around us, in space,
are metallic asteroids.

These are nickel iron asteroids,

and they contain an immense
mass of usable material

that we can use to
construct things in space

without having to expend
this huge amount of fuel

and energy in getting it there.

- We go from having to bring
that mass up into space,

to simply harnessing it from
what already exists in space,

allowing us to travel
further and further along.

- Amongst all the
minerals that can be found

in those planets, the most
valuable one for us is water.

Now, when we have
access to water,

we can generate
hydrogen from it.

And hydrogen can be used
as the source of the fuel

for the rockets.

- [Narrator] Using earthbound
mining techniques in space

is a major challenge demanding
cutting edge innovation.

- Mining in the space
is very different

from the mining we have here.

We need completely
new instruments to
be used over there

because the gravity
is different.

- [Narrator] Some
forward-thinking companies

are exploring an incredible
concept called Optical Mining,

touted as the most feasible
way to mine materials in space.

The process is like holding
a giant magnifying glass

to an asteroid and
drilling a hole

with the beams of sunlight.

We don't even have to touch
the surface of an asteroid

to dig holes in it.

- So it is the magnifying glass.

It's concentrating
the rays of the sun

into a focal point, and an
unhindered electromagnetic wave,

you can actually create
a blast that is enormous.

- If we can achieve
this asteroid mining,

we can basically use each
asteroid as a refueling station

and we can travel from one
asteroid to the other one

and get refueled and
go further and further.

And basically, we won't
have any limitation

in how far or how deep we
can travel into the space.

- Technology-wise, we're
getting to the point

where we can explore space.

We can go to the moon,
we can go to Mars.

Mars is our closest neighbor,

but it's also 20
light minutes away.

You want to phone Mars,

you might have a problem
on your spaceship

when you get to Mars,
you call back to Earth.

It takes 20 minutes for
the signal to get to Earth,

just to them to hear
something's wrong,

and then 20 minutes for
that signal to come back

to say, do this,
that's too long.

When people go out into
the outer solar system,

to Mars and beyond, they're
gonna be on their own.

We have to design and engineer
systems that are resilient,

that can sustain
people for months

and years at a time
in complete isolation.

Yes, you can have
a conversation,

but it's a broken one,

so you have to really be able
to do everything yourself.

- [Narrator] However,
there's still the problem

of how to get us
from the ground,

into space safely
without being strapped to

what is essentially,
a large bomb.

Some concept vehicles
for space tourism

are turning away from the
traditional rocket system

and towards Earth-like
devices that could bring us

closer to the stars.

In the future, space
tourism could evolve

into elevators.

Using a table anchored
to the Earth's surface,

the space elevator
would consist of a cable

stretching to a
counterweight in space.

The cable would be held taut
by the centrifugal force

generated by the
Earth's rotation.

Electric cars would
travel along the cable,

transporting people
and cargo into orbit.

This would eliminate the
need for rockets altogether,

making space travel accessible
and affordable for all.

- If you stand in one spot
and have a yo-yo in your hand

and spin, and you
spin fast enough,

the yo-yo will rise up and stay

in a circumferential orbit
around you as you spin.

Well, the same thing
happens in Earth's orbit,

is if we put a mass in
orbit and attach a string

back to Earth, and we
have that mass in space

be in geosynchronous orbit,

basically, we now
have a string attached

to an object in space.

And the idea with
a space elevator

is that we can then
attach basically,

a cab to that string
and pull it up,

just like an elevator,
to that object in space.

This has the potential to
revolutionize space travel.

Basically, it becomes
free to go to space.

We can move relatively
large masses into space.

We can move people
up relatively easy.

The problem with this
is we really don't have

a material that's strong enough.

So maybe someday, we'll find

some miraculous
material that allows us

to build space elevators.

If we can, it's gonna
make space essentially,

an everyday thing.

We'll be able to
hop on an elevator

and 20 minutes later,
you're in outer space.

- Ideally, if space travel
were to become more common,

it would require that
you're able to launch humans

into orbit without subjecting
'em to very high G forces,

which means slower
acceleration, propulsion,

probably more costly, but
nonetheless, would be safer.

- [Narrator] Such concepts
like space elevators

and balloon capsules
are very theoretical

with many problems that
still need to be solved.

In the more immediate
future, novel innovations,

like space sails, could
be a cost-effective way

to capitalize off of the
free solar power in space

to move objects after
the initial launch.

- Solar sails are an
interesting concept,

but it's based on a
very simple phenomena

that we mostly ignore on Earth,

and it's this conservation
of momentum theory.

And when we think of light,

it's hitting us and
we don't feel that,

but that light has momentum,

it's traveling from the
sun, if we're outside.

And then it's
hitting us on Earth.

- The sun is a ball of fire.

These are gases,
hydrogen, helium.

When you pop the electron
out, it becomes an ion,

and that's all the sun
is doing, constantly.

So it's spewing out
these ions of particles

with high energy,
coming in towards Earth.

Most of these burn
in the atmosphere.

Earth is a blanket of
atmosphere that disperses,

deflects, kills,
absorbs all these ions.

We get the light through,

but we get filtered
off, with the ions

and the plasma particles and
the high energy particles

that are floating in space

and bombarding the
Earth every second.

- If you have a piece of
equipment that's out in space,

away from all air
currents and gravity,

and it gets hit with the
photons coming from the sun,

it will feel it like
a sail in a sailboat.

- The amount of force being
given per photon is very small,

but in space it's a vacuum,

and so you don't
require anywhere near

the same amount of
force to actually

put something into motion.

- As we have a
spacecraft that deploys

a large sail in space, that sail

just continuously accelerates
that spacecraft over time.

Anytime we can harness
something from space

to power our needs,
it just means

we don't have to bring
that thing up with us.

- It's kind of diminishing
returns though,

because you need a really,
really big solar sail

to collect enough
propulsive energy,

to absorb enough photons
to give you that movement.

So if you're talking
about pulling

a space capsule through space,

you're talking about a
solar sail that's probably

the size of a US state,

like we're talking about
immense surface areas.

It's something that's doable

and we're certainly
looking at it

and it's a technology
that's actually been proven.

So we've actually sent micro
cube satellites into space

that have shown that
solar sails actually work.

So we're taking our first
steps down that road

to solar sails.

How practical they
become in the long run

is still yet to be seen.

- What excites me the
most about the concept

of the current space travel
and the current race,

and the desire of
people to go to space,

is the fact that in order
to accomplish those desires

we're going to come up
with new technologies.

And those technologies
are going to solve

a lot of practical
problems here on Earth.

- [Andrew] The future of
space travel is bright,

and we've only scratched the
surface of what's possible.

Even as we reach
further into our galaxy,

the challenges are
only getting greater,

but the solutions could
already be out there.

[upbeat music]