Original subtitles

[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]