Original subtitles

(exciting music)

- [Narrator] 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.

So how did we get to where we are now

and where are we going next?

(exciting music)

They've been dubbed steel monsters, war machines,

and apex predators of the deep.

- They're very stealthy craft that can sneak up

on other vessels or on cities around the world.

It really has a huge advantage in naval warfare.

- [Narrator] For a good chunk of modern history,

submarines have been primarily used for national defense,

but in recent times, submersibles have been

indispensable tools for exploration

and laying down vital underwater cables.

- Pipelines, electrical cables, communication cables.

Our internet infrastructure is on these cables

that go through the ocean.

- Using submersibles provides a really safe opportunity

to do some sort of repair work and maintenance

on crucial infrastructure.

- [Narrator] Submersibles are venturing into the depths

to unlock the secrets of the unknown and connect the world

in unprecedented ways.

However, their design has changed very little.

- We're really relying on the cylindrical shape

to provide the strength to resist that pressure.

- [Narrator] Innovation and new engineering

and technology could spawn radically different

submarines of the future.

The deeper we go, the more danger there is.

- The conditions are so harsh that if you could

do it unmanned, it's much better than risking humans.

- Unmanned vehicles are really important to understand this

vast portion of our globe that we haven't had access to.

- There's an entire world under the sea,

different creatures, different plant life,

a lot to discover.

It's almost like out of a science fiction novel.

- [Narrator] In 2019, Triton submarines,

deep submergence vehicle DSV named, Limiting Factor,

achieve the deepest dive made

by any human crewed submersible in history,

reaching a depth of 10,928 meters at the Challenger Deep,

in the West Pacific Ocean.

- This is a incredible feat of engineering

and it's basically like exploring a piece of space,

something that has been otherwise untouchable

and unimaginable to reach in human history.

- The DSV Limiting Factor went down to almost 11,000 meters

and that was a an amazing accomplishment

because for the first time, we managed to win

against all those crushing forces of the water.

- [Narrator] Triton Submarines was commissioned

to engineer and construct the Limiting Factor.

The project began with the forging of its pressure hull

from titanium, which was then pressure tested

to ocean depths, plus 20%.

- The pressures we're dealing with at 10,000 meters

are immense.

If you look at where the human is actually sitting,

it's a sphere. Spheres are incredibly strong.

They're built to support uniform pressures acting on a body.

- When we pay attention to the Limiting Factor,

we find that at least on the outside,

there seems to be some sort of composite or plastic,

which is easily moldable to particular shapes,

avoiding sharp corners or edges.

- In aerodynamics, sharp corners are bad.

Fluids, airs of fluid, waters of fluid,

of course, when these things are acting on a body,

you want rounded surfaces, they're easier to control

and they balance out the amount of stresses

that are gonna happen on that surface.

- [Narrator] Stress concentrators refer to multiple points

or features in a material where localized stress increases,

allowing for pressure to be released.

- Think of a cloth.

You can try to pull a cloth apart with some force

and you might not be able to do it.

Now, add a stress concentrator to that cloth.

So now add a little notch and pull it apart.

It's going to rip right at that notch.

The cloth without the notch, without the stress concentrator

was actually a stronger material

than the cloth with the notch.

- [Narrator] Normally for a submersible to descend and rise,

they're fitted with ballast tanks that are either filled

or emptied of water or air.

To safely descend to the deepest depths

of the earth's oceans, not one, but three

different ballast devices were engineered

for the DSV Limiting Factor.

- And we want a system that can withstand the deep depths.

So we want to avoid using traditional ballast tanks

that we fill in empty with water

because when we get that deep,

they're just gonna want to crush.

With this vessel, what they've done is they've decided to

use a foam material.

- [Narrator] Syntactic foam is a resin

mixed with hollow glass spheres.

This incredibly strong, incredibly buoyant material

can be machined to a precise shape

and gives the Limiting Factor its buoyancy.

- This vessel also has weights it releases,

so like a scuba diver, scuba dive divers also carry weights

down with them, and this helps them get passed

that surface buoyancy, it helps them get down,

but when you get to deeper and deeper depths,

you don't need that weight anymore.

So this vessel can relieve itself with some of that weight.

- [Narrator] This variable ballast system

carries a maximum weight of 100 kilograms

to control the speed of the dive

and to equalize its buoyancy just above the sea floor,

weights are jettisoned in five kilogram increments.

If any of the crew members on board should become unable

to operate the craft while submerged,

a single 100 kilogram weight held in place

by magnets, is released.

Ensuring the Limiting Factor finds its way to the surface,

no matter the circumstance.

- These are the designs that are incorporated

into this vehicle so that it can maintain buoyancy

which make it innovative from other submarines

because it doesn't use the traditional ballast tanks.

- [Narrator] Innovators have been working for centuries

to solve the basic challenges of operating a vessel

in the supreme environment of the deep sea.

- Life support on a submarine is a lot like being in space.

You have to bring the entire supply of everything

to support humans with you.

You need a source of oxygen, you need a source of air,

you need to get rid of CO2.

There are a lot of things you have to do

to support human life.

- Naively, when we think of submersibles,

we do just think going down, but we also eventually

need to think of coming back up.

And so how do you design propulsion

and how do you design vehicles that take both into account

and do it safely?

- One of the biggest engineering challenge of submarines

is dealing with the pressure.

We have to design these submersible vessel structures

to withstand that pressure.

- A far cry from the designs and engineering vessels

that we have today, early submarines were not much more

than airtight barrels that were designed to explore

just below the surface of the water.

- [Narrator] The world's first submarine was drafted

by William Bourne in 1578, an English mathematician

and former Royal Navy gunner.

He designed an enclosed craft made of wood

and bound in waterproof leather,

which could be submerged and rowed

beneath the water surface.

An integral part of his design, ballast tanks.

- Conventionally and traditionally submersibles

tend to have ballast tanks.

The reason for these ballast tanks is to allow the sinking

and the eventual floating of these submersible devices.

- [Narrator] Though, William Bournes design

never got past the drawing stage, it paved the way

for the submarines of the future.

- Controlling the dive for the submarine is crucial.

It's quite literally life or death for the crew inside.

If you go too quickly up or down,

there are really terrible effects on the body.

So this is a very important element to control.

- So for example, scuba divers can safely go down

to about 30 meters without a lot of issues.

Once you start getting below 30 meters,

if you're breathing normal air,

your body becomes saturated nitrogen.

And then when you come back to the surface,

that nitrogen can be released from your blood,

produce bubbles and give you decompression sickness,

the bends.

This has the potential to cause life-threatening injuries

to your spinal cord and other things.

So when we design submersibles,

we want to keep the pressure in that submersible

pretty close to one atmosphere.

So an atmosphere is the pressure that we experience

every day on earth from the weight of the atmosphere

pushing down on us.

For every 10 meters we go down,

the pressure increases by one atmosphere,

but all of a sudden we're going down a thousand meters

where we have a hundred atmospheres worth of pressure.

So now we have to maintain the inside of that submersible

at the same pressure as the surface,

but now we have a hundred times the surface pressure

pushing in at the same time.

That's a huge engineering consideration

to overcome in the design.

- The rate at which these submersibles rise and fall

don't concern just people.

They also concern the actual submersible vehicle itself.

Rising too quickly, that can have detrimental effects

on the integrity of the vehicle.

And likewise, also sinking too deep too quickly

could also cause some sort of catastrophic damage.

And so there's a very delicate balance

that needs to be struck.

- [Narrator] Triton Submarines continue to break barriers

with the Limiting Factor.

Aboard this vessel, operators and scientists perform

the deepest dives in the Red Sea

during a mind blowing ocean expedition, in 2020.

Capable of diving 11,000 meters deep

with carrying capacity for two people.

The Limiting Factor is ideal for exploring the unknowns

of the ocean teams venture down to this unique seabed

entering an underwater volcano.

And this isn't the only place.

In the Indian Ocean, in 2019, Triton crews

discovered never before seen species

at the deepest point of the Java trench,

including the sea squirts and the hadal snailfish.

- I think it's really important to continue exploring.

There's a lot of knowledge to be found

by looking at a part of our earth

that we've never really been to before.

I'm sure there's a wide range of plant life and sea life

that we can examine and learn a lot from,

but there's also a lot of materials and minerals

that may not have even been discovered yet.

- [Narrator] Braving the deepest crevices of the ocean

requires precision engineering.

Hull design and construction for submarines

is vastly different from surface vessels

because you have a whole new set of forces

you're dealing with.

- These submarines are like perfectly sealed capsules

and underwater any small damage to them

could be very catastrophic for the people on board.

- The primary concern is really the static pressure

that the material is subjected to over long periods of time.

And of course wherever there are seals,

so you've got the hatch propeller shaft,

all those seals have to also maintain their integrity

under the very high pressures that these vessels

are subjected to.

- At these kind of depths, if we get a crack

in our pressure vessel, we're gonna get a jet of water

coming in and that water jet is so powerful

it can literally cut through steel.

As engineers, we use water jets all the time

to cut through steel to make complicated shapes.

The same thing's gonna happen with a crack

in the pressure vessel.

It's literally gonna cut through the occupant.

In historic submarines, especially those which

used batteries, flooding the battery compartment

with sea water was devastating.

When we passed DC current through sea water,

we can produce chlorine gas and chlorine gas

has been used as a chemical weapon for many, many years.

So a gas that's burning people's lungs

and very quickly killing them.

So it's really, really important that that pressure vessel

be well sealed.

The second thing that happens is all of a sudden

we subject that occupant to the deep sea pressures.

Almost instantaneously their lungs would collapse.

It would literally crush the occupant.

- [Narrator] To fight off this oppressive force,

submarines require a specialized hull.

- So you can think of a submarine as a protective layer

between you and a massive amount of pressure

applied to it from the ocean.

And you've got internal air pressure with oxygen

that people are used to breathing,

pushing back a little bit.

If we over pressurize the inside of the vessel,

it could explode.

And if we don't prevent the exterior loads

from destroying the vessel, then it can actually implode

and crush everything within.

- [Narrator] The pressure inside The hull

is kept at a level that is slightly higher

than the surrounding water pressure,

which helps to prevent water from entering the vessel.

- With modern submarines, we want to try and make them

more damaged tolerant.

To that end, we have an outer hull and an inner hull.

The inner hull is our pressure containment.

And pressure containment is very difficult in submarines.

If we even have a tiny dent in that hull,

because of the nature of buckling,

it will actually cause the submarine to collapse and fail.

So to that end, we add an outer hull,

and the outer hull is kind of this added layer

of protection.

It's almost sacrificial.

So if we bump into something, we dent enter this outer hull,

it's not consequential and it kind of protects

that inner hull.

And then we can go back in the port and repair

that if need be.

So, the new modern submarine designs are more resilient

because of that.

- Construction of pressure vessels is a technology

that is immensely complicated.

First of all, the ceiling of it,

the joining of it, the welding of it,

making it into an actual pressure vessel

means you have no air leaks, it's air tight,

and that's not easy to make an entire submarine airtight.

And you can imagine the engineering challenges

of making something airtight in that large scale,

has to be precise, it has to be super airtight

and it has to be sealed off.

- So with all machines, there are safety factors involved.

We don't calculate the loads that we're gonna feel

on the exterior of this submarine

and design something to withstand only that exact load.

We tend to calculate the loads and then assume that things

will go wrong and we over-designed to eliminate

some of those future risks.

- [Narrator] A few years before the DSV Limiting Factor,

another breakthrough submersible would set the stage

for diving machines to explore the deepest caverns

of the ocean.

James Cameron used the filming of his blockbuster hit

"Titanic," as an opportunity to explore the famous shipwreck

through several dives using a fleet of submarines

priced at $3 million.

The $650 million payday from his smash hit

went towards the development of other underwater research

vessels to explore areas of the deep,

the specially designed Deepsea Challenger

brought James Cameron to the bottom

of the Pacific Ocean's Challenger Deep.

This low point in the Mariana's trench had been reached

by humans only once before, and Cameron was the first ever

to make a solo dive to this spot.

Cameron spent three hours collecting research samples

and taking photographs in this extreme remote environment

before returning to the surface in his submarine.

But the breakthrough in some of the most incredible

innovations in submarine designs

was the result of military action and demand.

On January 21st, 1954, the Navy's first nuclear

powered submarine, the USS Nautilus was launched.

The USS Nautilus represented a revolution

in not only submarines but maritime technology as a whole.

Its served as the experimental platform

for the current fleets of nuclear powered

military surface ships, submarines,

and commercial shipping vessels.

- In 1954, the US Nautilus is introduced.

This is the first nuclear powered submarine

and nuclear power's really a game changer.

Here we have an energy source that doesn't require us

to go to the surface every hour or two hours to get air.

It can essentially run for an incredibly long period

of time, years without needing to be refueled.

On top of that, because we can generate electricity

underwater almost indefinitely,

we can take water and electrolyze it and produce oxygen.

So all of a sudden we can have an infinite amount

of air underwater, we have sufficient power

that we don't have to get to the surface,

and really the only thing limiting our time underwater

is how much food we can bring with us.

So all of a sudden we have this stealth submarine

that we've always wanted.

We can go all the way across the Atlantic or Pacific oceans

sneak up on our enemy and they really won't even know

we're there.

- [Narrator] The Nautilus embodied the next generation

of submarines transitioning from slow underwater vessels

to warships capable of sustaining 20 to 25 knots

submerged for weeks on end.

- It's a revolutionary not only because of

the nuclear actor, but we start having these

hydrodynamic designs that are relatively efficient.

That means we can really achieve

some decent speeds underwater.

So it's actually going faster than most surface ships

can move.

So it really has a huge advantage in naval warfare.

- [Narrator] Today all the submarines in the US Navy

are powered by onboard nuclear reactors.

In 2020, the US Navy started working on the first submarine

of its most advanced nuclear powered

ballistic missile submarine class to date,

the Columbia class.

This class of submarines will be the largest ever built

by the US - 170 meters long with a displacement

of over 1900 metric tons.

The USS District of Columbia will be longer

than the Washington Monument is tall,

which is also 28 times the length of a male killer whale.

The total cost to build and maintain this behemoth

is estimated to be $15 billion and it will be crewed

by approximately 157 submariners.

Each Columbia class submarine will contain a nuclear core

to provide power for its entire 42 year service life,

eliminating the need for mid service refueling.

The Navy's newest submarines must also be the stealthiest.

The USS District of Columbia will use an electric motor

to turn its propellers instead of the louder steam turbine

systems used on earlier nuclear powered submarines.

- There's a number of ways in which you could reduce

noise generation.

So one is by changing the nature of the engines themselves.

So moving towards nuclear powered electric engines,

which are intrinsically quieter.

- [Narrator] And nuclear power does more

than provide stealth.

It's also a much greener energy source

than traditional diesel powered submarines.

- Nuclear power has understandably had a bit of a bad rap

for some things.

When things go wrong, things go catastrophically wrong.

But when things go right, it's actually a very energy dense

form of energy creation, which is very useful

and it's actually much cleaner

than a lot of other alternatives.

- It has a very low environmental impact

in terms of CO2 emissions, so it's good for greenhouse gases

and global warming and it has the right kind of power levels

that we need for submarines.

- [Narrator] Although it's not all good news,

as spent nuclear fuel is highly radioactive

and requires careful handling and long-term storage

due to its potential hazards and may take thousands

or even millions of years for them to decay significantly.

- One of the things that we need to be concerned about

when we're talking about nuclear is how we store

the nuclear waste.

In Canada, for example, where we store

a lot of our nuclear waste is in the Canadian shield

where we've dug very extremely deep caverns

where we store these things so that

they can naturally decay.

- Nuclear power has a really big advantage for submarines

in that you don't have to refuel very often.

Nuclear power cells have a very long life.

So once you are up and running,

you're able to stay down under the surface of the water

for a much longer time.

To simplify how a nuclear reactor works on a submarine,

the nuclear reactions create a lot of heat.

That heat is then harnessed to create steam,

and then the steam is used to make propulsion.

- You throw a neutron at an atom, then when it splits,

it breaks down into its component parts,

creating more neutrons, and then that hits other atoms

and then creates more neutrons.

And so this is a cascade effect.

And so those neutrons are usually in a uranium

or plutonium system.

And the reason why we use those is

because they pack the most amount of energy.

- [Narrator] Plutonium is chosen for military uses

because it can release a significant amount of energy

making it more powerful.

However, it has a relatively short half-life,

meaning it decays relatively quickly

losing its potency over time.

- While uranium is more sustained, but it packs less punch,

which is why we have them for civilian use.

- [Narrator] The first test reactor started up in the US

in 1953 paving the way for the fleet

of nuclear submarines to come.

- We think of nuclear reactors as being

these large structures that we see

as we drive down the highway,

but there's no reason why they have to be.

You can scale them down to quite small sizes.

So there's a lot of interest currently

in what are called small nuclear reactors

that can be used by local communities,

either to generate power or by certain industries.

For example, a large steel plant could be powered

by a small nuclear reactor.

If you reduce the size of these even more,

then you can now think about putting them onto vehicles,

of various kinds where you can create power

and you have a power source which is very compact

and lasts a long time and can be built in a small way

that is self-contained and quite safe.

- [Narrator] Another key to submarine safety

is ensuring the crew has ample oxygen to breathe on board.

In order to remove excess CO2

from a submarine's atmosphere,

crew members must use a process called CO2 scrubbing.

This chemical process uses sodium hydroxide

and calcium hydroxide or soda lime inside onboard scrubbers.

When these chemicals react, the soda lime traps the CO2,

removing it from the air.

- So it's a question of maintaining the oxygen level

and removing the toxic chemicals,

particularly carbon dioxide from the atmosphere

to maintain quality of life and life itself,

whether it's submarines or spacecraft,

the same issues supply.

- [Narrator] Unraveling the critical components

of a sub design so it can safely operate

in the depths of the ocean, took centuries

of trial and error and testing in shallower waters.

The first practical submarine was built by Dutch engineer

Cornelius Drebbel while he was working

for the English Royal Navy.

Invented in 1620, this submarine was a rowboat

covered with greased leather, powered by rowers,

pulling on oars that protruded through leather seals

in the hull.

- This first attempt at underwater mobility

was only able to go down about five meters in the Thames.

Like many forms of transportation here,

we're seeing a reliance on human power

that's been eventually far surpassed

by more current and advanced technologies.

- [Narrator] Drebbel initially created this submarine

with the goal of underwater exploration

while working under special order for King James I,

the submarine was successfully tested several times,

reportedly once with the king himself on board.

However, despite its functionality,

the sub never gained the interest of the Royal Navy.

Today, the British Royal Navy boasts

some of the world's most advanced submarines in their fleet.

The five astute class subs are advanced, nuclear powered

attack submarines on the cutting edge of technology,

the most advanced subs ever operated by the Royal Navy.

They're armed with long-range Tomahawk, land missiles

and Spearfish heavy weighted torpedoes.

Throughout their 25 year service period,

the nuclear reactors powering the astute class

will never need to be refueled.

Weighing in at 7,800 tons and 97 meters long

the astute class are a force to be reckoned with.

Serving as the Royal Navy's attack dogs for decades to come.

Submarines first emerged in military operations

during World War I.

Several countries began using submarines on a large scale

to attack civilian shipping and occasionally enemy warships.

This created the need for anti-submarine warfare

or ASW and began a hide finder competition

between submarines and ASW forces.

- There's huge downfalls with these early submarines

for having to surface all the time.

It basically means that they can easily be spotted.

So if there's another vessel in the area,

they're immediately gonna be spotted, identified,

and then they can't dive again.

And because they're not a large ship,

they don't have surface armaments,

they're kind of a sitting duck once they get spotted.

So we really want a vessel that can stay down a long time

because they really don't have capabilities

to defend themselves.

- [Narrator] Early ASW mostly relied on the use

of static defenses like underwater mines or chain-link nets

to prevent the movement of subs into secure areas.

Torpedo nets were also hung from ships

as an anti-sub defense to block torpedoes

from reaching their hulls.

Ships would also optimistically try to damage submarines

by towing grappling hooks connected to explosive charges

in the hopes of snagging a sub or throwing charges overboard

in the direction of a suspected vessel.

The war sparked heavy research into higher tech

submarine detection.

One of the most common ways to detect submarines

is using sonar technology.

- The first sonar like system was invented by Louis Nixon,

in 1906.

- [Narrator] A naval architect Nixon was using the system

to detect icebergs under the water to help ships navigate.

- Thanks to the development of sonar,

we were finally able to actually see what was around us,

whether it be land masses or any other kind

of object underwater and especially enemy vessels.

- We don't necessarily have to worry

that we're gonna be seen in a submarine underwater,

visual cues are limited when you're so far down

in the depths of the ocean.

But sound travels pretty far.

And so generally, if people wanna detect us

while underwater, they're going to be listening

for our position.

And so if we want to stay quiet,

we have to make sure that we don't emit any noise

that can be picked up by detectors

that are listening for a position.

- [Narrator] Traditionally, there are two types of sonar,

active and passive.

- Active sonar is based on sending the mechanical wave

and waiting for its reflection 'cause the speed

of this wave is known.

Therefore, we can calculate a distance.

And passive sonar is a technology which is based

on active listening, monitoring the sounds under the water.

So when there is a submarine, it has an engine

and that generates a specific frequency,

which is very different from the other sounds

that are naturally there.

- Your ability to pick up a signal really depends

on the strength of that signal.

So you can have a very powerful detector,

but then it'll also pick up a lot of noise.

So you have to have the ability to filter out all that noise

to ensure that the information coming at the detector

is in fact a submarine and not a power plant

operating on ground nearby.

- It's exactly the same technology that is used with mothers

to be able to take images of an unborn infant.

So you can see what's going on and detect

if there's any problems.

- [Narrator] In response to the creation of sonar

came hydrodynamic improvements to the hull

and the propeller.

- One of the things that happens when you're moving

underwater at high speeds is you can create

cavitation bubbles.

Basically, if you go fast enough,

will create low pressure pockets around discontinuities

in the hull, and when those bubbles of water vapor form

and then collapse, it makes a lot of sound.

The same thing happens for propellers, as a propeller turns,

if it's not well designed, it produces cavitation bubbles

and those are easy to hear.

So we start designing submarines that are designed so that

they're hydrodynamic.

They don't produce these cavitation bubbles.

We have a huge amount of technology going into designing

propellers so that they don't produce cavitation bubbles.

- [Narrator] The German design 212CD

and the British Dreadnought class

ballistic missile submarine have outer hulls

designed to deflect incoming active sonar.

They also incorporate traditional passive sonar stealth,

including complex anechoic coatings outside

the pressure hull designed to absorb or reduce

the reflection of sound waves and electromagnetic waves.

- With the development of sonar had to of course

come the opposite of sonar.

Being able to hide from sonar was very important,

tactically speaking.

So we achieve this by developing a series of materials

that help you to not reflect sound.

- Metals are typically quite reflective.

So if you have something which is more compliant

on the surface that will absorb an incoming wave

and not just reflect it back,

then you can help to deaden the sound.

- By covering a submarine in something like let's say

a soft rubber tile, the profile might not

be completely invisible, but it might look to your enemy

like maybe it's a whale or maybe it's something

else underwater.

- Now researchers are trying to combine kind of bubble wraps

into tiles so the wave wouldn't reflect at all.

- Any kind of gas is much more squishy

than would be any kind of solid.

So if you can embed gas bubbles into a polymer surface,

it will be more sound deadening.

It's not that different than the kind of sound insulation

that you might have in a concert hall.

You're using both material and airspace

to be able to produce sound deadening.

- [Narrator] Not only have engineers use sound deadening

materials on submarines, new submarine hull designs

include angles to deflect sound in interesting ways.

- The hull shape is designed in a bit of a different way

so that it doesn't reflect sound back to the source

of the sonar emitter.

It actually deflects it away.

So this would help you hide or change the sonar profile

that the enemy would be seeing of your ship.

- The sound wave comes off one of these angles,

but it doesn't reflect completely.

You actually get multiple waves emanating,

allowing this submersible to be slightly less detectable.

- We start providing sound insulating materials

to the hulls of our vessels so that they become

even more stealthy.

So again, there's this arms race between how good sonar is

and how silent we can make our vessels.

- [Narrator] These novel sound absorbing materials

also reduce the amount of acoustic pollution

emitted by a submarine, which not only maximizes stealth,

it's better for marine life.

- Acoustic pollution is noise artificially created

where it disturbs the natural environment.

If you have artificial sources of sound

and they're terribly prevalent in places

where whales are migrating, then that can cause,

disorientation and so it's important

to do what we can to mitigate that.

- The North Atlantic, the whale is dead or gone

because of the cargo ships in the Labrador corridor,

going up and down from West Indies to Canada.

So we might have to think about new ways of moving things.

Maybe submarines would help because if you're underwater

with the full sensor capability, you can avoid whales,

you can avoid fishes,

you can avoid things you want to avoid.

I feel it might be a safer for marine lives

to have us travel in submarines rather than ships.

- [Narrator] Without the evolution of sonar technology,

the incredible unmanned submarines of today could not exist.

Innovative companies are looking to disrupt

traditional methods of planning

for underwater infrastructure.

Ocean Infinity, a pioneer of large scale

marine robotic operation is assembling a fleet

of autonomous underwater vehicles to perform

oceanic research, including mapping the sea floor

and environmental monitoring.

This up and coming company is at the vanguard

of unmanned underwater vessel development.

UUVs deploying the world's largest fleet

of marine robotics in 2017.

3 years on and their engineers began constructing

the groundbreaking Armada fleet featuring robotic ships

measuring up to 78 meters, outfitted with high tech sensors

and cameras, their UUVs and remotely operated vehicles,

ROVs collect data beneath the waves and send it

to the technicians at the remote control center on land,

allowing critical decisions to be made

about undersea development without putting any human lives

at risk.

- We have pipelines, electrical cables,

communication cables, our internet infrastructure

is literally based on these cables that go through

the ocean, and every so often they're in need of repairs.

So we need to figure out a way to repair them

rather quickly, if you wanna stay connected.

- So when we think about human infrastructure underwater,

a lot of that is around oil and gas.

These have fixed lifespans, they have damage that can occur.

They need to be inspected.

And sending humans down to those depths is difficult.

We actually use saturation divers currently,

and saturation diving is really unbelievable.

You take humans and you put them in a chamber

and compress the air in the chamber down

so that they match the pressure of the sea floor

and then they can work.

But unfortunately, because of the nature

of saturation diving, those divers actually have to spend

days or even a week or longer decompressing.

Saturation diving is very dangerous,

and we really don't want to put humans

into this environment.

So when we look at repairing underwater pipelines,

we want autonomous technology.

We want vessels that can go down there

and do the assessment so engineers can sit on the surface,

watch on screens, rather than have physical people

in this hostile environment.

Autonomous inspections, autonomous vehicles

to do welding and repair to underwater pipelines

is really, really important technology.

- [Narrator] Development of the first

autonomous underwater vehicles began in the 1960s

and accelerated rapidly into the seventies,

eighties, and nineties as humans became

more and more enthralled with deep sea exploration.

- It's incredible that life exists in these deep,

dark places.

And what sustains it are the things

that we normally associate with life like oxygen,

light don't exist down there.

- [Narrator] However, the mysteries of the deep sea

are slowly being revealed.

Originally built in 1986, the National Oceanic

and Atmospheric Administration's Aquarius Reef Base

located off the coast of Florida in the USA

is the only undersea laboratory in the world.

Anchored at 18 meters deep, the habitat itself

has just over 37 square meters of living in laboratory space

and two-way stations holding pockets of air.

It allows scientists and researchers to live and work

underwater for extended periods and undersea explorers

can top up their air tanks during a dive.

The Aquarius system has two other elements,

a life support buoy at the surface,

and a base plate that secures the habitat

to the ocean floor.

All elements must be in good working order

to continue welcoming visitors.

- It allows for a lot of new research,

a lot of new understanding of deep sea biology,

and a lot better understanding of our world,

which is mostly water.

We understand very little about our oceans.

In fact, we now know more about space

than we do about our deep oceans.

- [Narrator] Not only is Aquarius ideal

for underwater research, it also trains astronauts.

NASA's extreme environment mission operations program

sends astronauts into the ocean where they can encounter

the same challenges they would face in space

and must troubleshoot obstacles in an extreme environment.

- Well, there's a lot of parallels between space exploration

and underwater exploration.

In both cases, you have to carry all of the necessities

of life with you when you go.

It's a very constrained environment that has all sorts

of human factor implications in terms of how people adapt

to spending long periods of time under those environments.

- [Narrator] Today's underwater habitats

and high tech submarines wouldn't be possible

without the post-World War II submarine revolution.

A decade of incredible innovation,

which began when German U-boats were captured by the allies

at the end of World War II.

- In a 10 year period from 1945 to 1955,

submarines were really transformed.

They went from being ships that could submerge

for brief periods of time to true underwater vessels

that could remain underwater for weeks at a time

and easily navigate.

- [Narrator] The U-boat was by far the most sophisticated

submarine of its time, decimating its enemies,

during World War I.

The Germans leveled up their designs for World War II,

where commanders operated their subs

with extreme discipline, employing stealthy tactics

to avoid detection by sonar used by the allied forces.

- When we look back at the history of submarines,

when we're talking about World War II,

the German engineering's really amazing to see.

- [Narrator] Showcasing streamlined hulls that reduced drag

and made them more efficient underwater

and snorkels for diesel engines,

a retractable mast that allowed the diesel engines

to run while the submarine remained underwater.

The highly advanced U-boats inspired new thinking

in every major Navy.

- We sort of got a little bit better at building engines,

but that came with its own issues because an engine needs

air and it produces exhaust.

And so we needed to have this constant supply of air

with oxygen, and then we needed to then exhaust that exhaust

from that engine to make sure that those toxic fumes

weren't gonna be kept inside.

So we at first started off by simply having a snorkel.

- Snorkel, it has to be one way.

It has release air. You don't need water coming in.

It has to have a one way valve,

and it has to have a storage container that is pressurized.

So you need to make sure that you have a one-way vacuum

suction pressure, and then you need to exhaust

what you're breathing out because that's adding volume

of air in your submarine that you need to exhaust

at the same time.

So that's another challenge as to how

you're gonna exhaust this.

- Basically, if you stay a few meters below the surface,

the snorkel allows you to run almost indefinitely

with a very small visible footprint above the water surface.

This makes it much harder to detect the submarine,

and you can run long distances, slightly submerged.

So this is kind of that step between

having to come back to the surface all the time

and between nuclear submarines, which consensually stay down

for, you know, weeks or months at a time.

- [Narrator] It wasn't until nuclear power eliminated

the need for air supply that submarines had the ability

to stay underwater indefinitely.

- So when we realized that the power we needed

on a submarine was electric in nature,

we decided to just generate the electricity directly

and skip the whole diesel part.

The natural progression was that we needed

to have a power plant in the submarine.

And the only power plant I can think of that doesn't require

oxygen and it doesn't produce toxic fumes

is a nuclear power plant.

- [Narrator] But staying submerged is not without its risks.

In August of 2000, the Russian submarine Kursk

sank to the bottom of the barren sea,

located up the northern coast of Norway and Russia,

it's considered one of the worst submarine disasters

of all time.

The entire 118 man crew perished during a naval exercise

after two undersea explosions destroyed the vessel.

Rescue efforts were greatly hindered

by frigid water conditions and poor underwater visibility.

- Not only did this accident have a serious human toll,

but it also raised significant questions

about this in response to submarine

and anti-submarine warfare.

- [Narrator] To ensure that such a tragedy

never happens again, in 2013,

NATO developed an international hub to combat

submarine emergencies.

A direct response to the Kursk disaster.

Teams from 41 nations bond together to train

for worst case scenarios so that the rescues

can be performed successfully in all types

of sea conditions.

These training exercises are also an opportunity

to test out the latest submarine technology

from every country involved, including

many submarine rescue vehicles

and specially designed rescue chambers.

As submarine rescue methods continue to evolve,

so do submarines themselves.

Made in the United Arab Emirates,

the Kronos armored submarine could be a game changer

for the future of underwater exploration and operations.

Inspired by manta rays and spacecraft,

researchers and designers fuse these ideas together

to create this eye-catching diving machine.

Its folding wings allow for ease of transportation

to the water and its hydrodynamic design

delivers high performance and impressive efficiency

above and below the ocean waves.

Up to 10 passengers can climb aboard comfortably

and travel across the water at up to 80 kilometers per hour

and 50 kilometers per hour when fully submerged,

its innovative, Hull design reduces fuel consumption,

increases maximum speed, and provides exceptional stability.

With a working depth of 100 meters

and a maximum critical depth of 250 meters,

the agile Kronos can be used for commercial, rescue

and combat operations.

Equipped with a diesel generator,

electrical engine, and a water jet

air compressor and torpedoes,

This submarine is ready for anything.

And thanks to its dual sources of power,

the Kronos can run for up to 54 hours in hybrid mode.

Before sub-sea propulsion systems had advanced for longer

and faster operations under water, submarine hulls

were tailored mostly for use at the surface.

- While the submarine hull has remained

relatively static over time,

every now and then we see a re-imagining of this design.

- [Narrator] The teardrop hull shape,

which was designed to favor submerged operations

was used in the early stages of submarine development.

But in the early 19 hundreds, outer hulls resembled a ship

making them most effective at the surface.

During World War II, as submarine technology advanced,

hull designs reverted back to the teardrop shape again

to reduce drag and noise underwater.

Since the early 19 hundreds,

underwater noise interfering with hearing

has been a problem.

During World War II, scientists studied background noise

and invented acoustic minds devices that would explode

when triggered by passing ship sounds.

However, they needed to know how loud the noise was

to set these devices correctly,

so they only went off when a ship was around.

This need led to better systems for measuring

underwater noise.

For instance, the passive acoustic monitoring, PAM systems,

consist of strategically placed hydrophones

that listen for specific acoustic signatures

to monitor and identify various underwater sound sources,

including ship traffic, marine mammals,

and seismic activities.

Although the first submarine used in combat

came centuries earlier, and as they had no engines,

they were pretty quiet but impractical.

- When you look back in say 1775 at the Turtle,

it's really one of the first examples of a submarine

being used for military applications.

This was designed to allow the operator to attach bombs

essentially to the hulls of British ships

during the blockade of New York during the US Revolution,

but has a lot of design concerns.

It's really a one man vehicle.

This occupant has to operate a propeller by hand,

try to control where this vessel's going,

try to control the buoyancy, try to get close

to another ship's hull and attach a bomb

and do this all at the same time without sinking

and without staying at the surface.

So it's too much that's going on.

There's too much for the occupant really to be able

to control this vessel well,

but has all the real equipment of a modern submarine.

It has a propeller, it can move, it has directional control,

it has buoyancy control, and it has an objective.

It's actually doing something so you can start to see

the engineering evolve.

- [Narrator] But even for the world's most advanced

submarines, navigating the depths of the ocean

is a constant battle.

- You're basically blind.

Anybody who's tried to scuba dive or swim in a muddy bay,

you can't see anything.

You can't see your fingertips.

Certainly you can't see far enough

if you were driving a submarine not to bump into something.

So with submarines, we really need some type of system

that allows us to see our environment

when we can't really use visual sensors

or even visual observation directly.

- [Narrator] When on the surface,

GPS can accurately determine latitude and longitude.

But this system doesn't work when the submarine

is submerged.

Submarines are equipped with an inertial navigation system

INS, which measures the boat's motion

and constantly updates their position.

These systems were initially developed for rockets,

but by the 1960s, inertial navigation became

a critical core technology for all US military submarines,

strategic bombers, and ballistic missiles.

Because it does not rely on radio signals,

the INS allows submarines to navigate

while remaining hidden beneath the surface.

Measurements provided by accelerometers and gyroscopes

track the position and orientation of the submarine

relative to a known starting point,

orientation and velocity.

As technology evolved, mechanical gyroscopes

were replaced by fiber optic gyroscopes,

which provided the advantage of having no moving parts.

As we navigate under the water surface,

we are seeing the potential that the oceans could provide us

with the green energy we desperately need

to stop climate change.

The Ocean Infinity teams regularly deploy

their robotic fleet to the bottom of the sea

to support underwater green energy initiatives.

Marine energy generated from ocean waves,

currents, tides, and temperature changes

has the potential to be the world's largest

renewable energy resource.

But one of its biggest obstacles is the limited number

of suitable sub-sea locations.

An issue that Ocean Infinity is aiming to solve.

As their autonomous submarines continue exploring

and mapping the sea floor, more potential locations

for marine energy initiatives can be revealed.

Green power sources for the submarines of the future

are also evolving.

- A lot of the countries that tend to have

nuclear submarines, they tend to have very large

military budgets, and so nuclear reactors

or nuclear energy sometimes require

billions of not just research,

but also in capital money to produce.

And they should not go unnoticed that many nuclear reactors,

at least for civilian use, have always gone over budget.

- So while installing a nuclear reactor in a submarine

did technically unlock the ability to explore

the oceans indefinitely, it's not always the most

financially feasible solution.

And we need to think of more practical ways

to get the autonomous drones floating around and exploring.

- So when we look at historic battery powered submarines,

we were really limited our choice of batteries

in the early part of the 20th century,

really, lead acid was the technology of choice

and lead acid batteries are very heavy.

They don't hold a lot of charge.

They don't have a lot of capacity to allow the submarine

to go great distances.

With the advent of modern lithium ion batteries,

lithium iron phosphate batteries,

these batteries are much lighter.

Lithium's a very light element.

They have very high charge to weight ratios,

so their density is low, but they can still hold

a huge amount of electrical charge.

And this provides a great opportunity for submarines, again.

We can now build batteries that will allow us

to power submarines for relatively long periods

of time underwater.

So when we're looking at short range military operations

or research and scientific vessels,

all of a sudden we now have a technology that allows us

to do it at much lower cost than using a nuclear reactor.

So we will see lithium batteries become part of submarines

going forward.

- [Narrator] As we look to the future,

the new designs and innovation in deep submergence vehicles

should mean we will be able to go deeper

and for longer than ever before.

- The DSV Limiting Factor broke through this glass floor

and allowed us to realize that we can go to those depths.

And once we learned that something is possible,

we become pretty creative and find ways to use

that possibility to explore and to do things

we previously didn't know were possible.

- If we think about extraterrestrial life,

we think we have to find planets that look like the earth.

Well, life exists in these deep dark places

and I don't think we really understand

what it is that sustains life in the deep oceans.

And that would be fascinating to know more about.

- I'm really excited for future submarines

because we really need to explore mankind's last frontier,

and that's the deep oceans.

We really don't know a lot about the deep oceans

and the future vehicles are gonna allow us to get there.

- Places we've never even thought of exploring before

and do precision work at scales

we've never considered before,

and allow us to expand the ability to both understand

the ocean and to utilize the ocean in ways

we haven't even thought of.

(exciting music)