Original subtitles

NARRATOR: We live in a built world.

Engineering and technology,

built upon innovations and inventions,

stretching back thousands of years.

Some of our creations, like machines,

boost our bodies' abilities.

Others help us reach outside our comfort zones.

We have left an indelible mark on the planet.

And now the time has come to use our skills

to make a better world.

WORKER: ...two, three, lower.

NARRATOR: Like inventing a new way to fly,

electrically.

Or a device that can smell...

ANN PERSON: I get very excited when technology works.

NARRATOR: ...to save food from going to waste.

THARINDU MADDUMA: Food waste is enormous global problem.

NARRATOR: Creating a machine... RESEARCHER: Rob, I'm going in.

NARRATOR: ...to heal coral reefs.

ARAN MOONEY: How do we fix the environment that's

sort of dying in front of us?

NARRATOR: Or even combining a traditional work of art...

LEWIS STETSON ROWLES: We see this amazing opportunity to use pottery.

NARRATOR: ...with modern chemistry...

NAVID SALEH: Could you actually make something like that?

Do you have something similar?

NARRATOR: ...to provide clean drinking water.

I made a shape similar to that.

NARRATOR: "Building Stuff: Change It!"

Right now, on "NOVA."

♪ ♪

NARRATOR: Human beings have been

changing our surroundings for thousands of years.

The signs are written on the land itself.

We're builders and makers.

And the evidence is plain to see.

ADAM STELTZNER: Our whole lives are constructed.

We live in the modern world in a very altered environment.

And all of that alteration

starts and finishes with engineering.

ANDREA ARMANI: Engineering can transform a community by

bringing power, bringing water, growing food.

DEB CHACHRA: Taking sewage away, the power grid, telecommunications,

these are all engineering systems

that are not about making any one of us

smarter or stronger or faster, but making us, collectively,

have more agency and more capacity.

NARRATOR: But building the modern world

has come with steep costs

and changes to more than just the land,

like altering the chemical composition of our atmosphere.

But now there's a new generation

that wants to engineer a cleaner planet.

So, as an engineer,

when you see the world as it is, you begin to think,

"How could we make it better?"

So that's our job, to take the world as it is

and make it better.

Everyone's engineering background,

it comes from that purpose of saying,

"I want to solve a problem that just changes the world."

NARRATOR: One daunting challenge we face today

is to reduce the carbon emissions

caused by burning fossil fuels.

Electrifying transportation offers some hope.

On the ground, cars, buses, trucks

and trains are gradually making the switch.

But what about in the air?

Is there a way to go green in flight?

At Joby Aviation in Marina, California,

engineers think so.

They're testing a new kind of aircraft.

WILSON: So, today,

uh, Joby's flight test team

is putting the aircraft through its paces,

flying range and endurance missions.

NARRATOR: The aircraft is a hybrid--

like a helicopter, able to take off vertically,

but also, like an airplane,

able to fly horizontally at high speeds.

And it's completely electric.

ARMANI: The challenge is, you know,

how do we make a personal helicopter?

How do we make them sustainable?

Right, we don't want to bring more jet fuel into the world.

WILSON: It is routine for us to fly

three times a day, cruising around at about 100 knots.

NARRATOR: Joby's ultimate dream

is to deploy the aircraft in cities around the world

as flying taxis,

reducing congestion on the ground.

Today they're in the final testing stages

of their latest prototype.

But despite promising results,

they're not taking chances with humans on this round.

WILSON: There's actually nobody on board

the aircraft while it's in flight.

The pilots are simply sat on the ground

in the ground control station, flying the aircraft remotely.

NARRATOR: Technically, it's known as an EVTOL,

Electric Vertical Take Off and Landing.

But it's also capable of level, forward flight.

As we're going through our airspeed expansion,

we are testing a, a certain airspeed,

performing a bunch of tests

to make sure our aircraft is stable,

and then expanding into different airspeed regimes

all the way to fully wing-borne flights.

NARRATOR: This day's testing is winding down.

A sudden tilt on touchdown is quickly corrected

by the remote pilot.

Something to tweak for future flights.

WILSON: Our analysts look at the data after the flight

to make sure that the aircraft is performing

exactly as we expect it to.

NARRATOR: As Joby engineers work to realize their dream,

significant engineering challenges remain

before regular passenger flights become a reality.

DARAIO: As you're trying to develop transportation devices,

you really need to understand the environment

in which these systems need to operate

and iterate the engineering design,

the components, the testing specifically to those needs.

NARRATOR: Today, it's not uncommon to see helicopters in city skies.

But they have drawbacks.

They're noisy, the learning curve to fly them is steep,

they have limited forward speed, and they burn fossil fuels.

Joby's design is an attempt to address all of those problems.

VALERO-CUEVAS: You have identified a problem.

Can you make an airplane

that uses propellers like a helicopter

but doesn't have that noise?

Well, you've dreamt it up.

The question is,

how do you actually bring it into existence?

WORKER: All right,

one, two, three, lower.

NARRATOR: One of the biggest challenges

has been to invent a new propulsion system.

The idea was to design a vehicle for four passengers and a pilot

that can rise straight off the ground

and then somehow transition to fly like an airplane.

Joby's solution-- six electric motors

that can individually pivot,

propelling the vehicle up to 200 miles per hour,

eliminating fossil fuels and reducing noise,

a critical improvement

if they have any hope of widespread adoption.

That's what gives the aircraft its unusual profile.

Six smaller propellers

that are quieter than a single helicopter blade.

But because they're small,

everything depended on finding the right propeller shape,

a surprisingly complicated problem,

part art and part science,

with much of the know-how

handed down since the early pioneers of powered flight.

These propellers may seem wholly modern.

But if we trace their evolution,

we can see clear connections to the past.

Leonardo da Vinci's notebooks

contain one of the most famous early conceptualizations

of a device resembling the modern propeller.

Da Vinci, in turn, may have been inspired by

the Greek philosopher Archimedes and his screw-shaped water pump,

or even by nature.

Certain plants and seeds, like the maple and sycamore,

have evolved similar shapes.

When they fall from trees, they look and work

remarkably like helicopter blades.

At Joby, the design team is looking for the best shape

to balance power and noise.

We went through a lot of experimentation

with actual propeller, uh, prototypes.

We needed to put real work in, in terms of experiments,

to really understand this phenomenon.

NARRATOR: To reduce noise, it helps to understand what causes it.

As each propeller blade slices through the air,

it creates pressure vibrations.

The strength of those vibrations

depends in turn on a propeller's shape,

how fast it spins

and the number of blades.

MIKIC: So we iterated with a number of designs.

We took blades with a lot of blade area

and then much thinner blades and, uh, trying to see

how that results in acoustic generation.

These propellers are turning much slower

than traditional helicopter blades.

We varied the shape, a lot of experimentation.

I think this trial and error system

is something that allows us to ever more refine design,

produce and, uh, test, which, in multiple iterations,

allows us to arrive to, uh, to optimal solutions.

NARRATOR: The company has tested several blade shapes,

hoping to find the best combination

of efficiency, lightness and durability.

To test each new propeller design,

the company has built a large circular track

in an old quarry near Santa Cruz.

MIKIC: In quarry, we have what we call "The Whirlybird,"

which is a track kind of like a roller coaster track

that goes around in circles.

And we have to test this propeller

not only in hover conditions, but through all the conditions

that it experienced through transition

as well as forward flight.

NARRATOR: On the track,

they test each iteration of the propeller

for durability and blade design,

as well as for noise.

MIKIC: And then we adjust the angle of the propeller,

the speed of the propeller,

the variable pitch on it

to see how it operates in different regimes of flight

that the real airplane would experience.

And we can do this for hours on end,

days on end, uh, to see how the system performs.

ARMANI: The design of a propeller

is a very theoretically heavy lift.

However, at the end of the day, experimental results rule.

And their ability to build that huge test ring

to really, you know, compare their experimental results

with the, the theoretical predictions

are really what allowed them to advance

and push their entire plane forward.

NARRATOR: Ultimately, they discovered that their original design,

which was wider,

actually performed better than subsequent slimmer designs.

The greater surface area allowed them to slow down

the propeller's rotation speed,

reducing noise while meeting power requirements.

MIKIC: When you do the experiments,

you realize you're going down

the wrong path, then you start to go back and see,

like, well, why is the thing that I tried to do

that makes things better actually worse?

So you challenge your own assumptions.

DARAIO: Challenging assumption is something that

is an essential component in engineering.

Being able to harvest the advances of divergent thinking

and creative thinking

is something that, in the end,

promotes innovation and allows us

to advance technology much faster.

NARRATOR: A change to the shape of the propeller

helps with the nature of turbulence

generated by the blade.

Exactly how they did it,

a Joby representative said, is a trade secret.

But the result is a vehicle that the company says

produces 100 times less acoustic power than a helicopter.

Eventually, they're hoping to expand their test program

to include passengers

and move toward full certification

from the Federal Aviation Administration.

DIDIER PAPADOPOULOS: Safety is non-negotiable.

Look, I'm gonna put my kids on these airplanes,

and so this is, this is close to me,

just as it is close to everybody else.

WILSON: Now being able to travel

routinely with an aircraft like this,

and be able to do it relatively low cost

and super available to the masses, is so exciting.

NARRATOR: Today, air travel accounts for an estimated 10%

of the carbon produced by all transportation.

It's this kind of experimentation

that could lead to bigger changes in air travel.

Electrifying aviation is one of the hardest

engineering challenges we face.

But not every problem requires such a difficult solution.

When it comes to finding ways to reduce carbon emissions,

there is some lower-hanging fruit.

Over thousands of years,

we've gotten more and more efficient

at growing food for an ever-growing population.

But the road from farm to table can be long and wasteful.

Globally, a third of all crops go bad

before they reach the table.

And with food production accounting for about 30%

of global greenhouse gas emissions,

reducing food waste could be one solution

to our climate problem.

At least, that's the idea behind a Norwegian rot-sniffing robot.

The BAMA food warehouse in Oslo, Norway.

NARRATOR: Anne Person is the director of quality assurance.

We get about 2,000 pallets

in here every night.

NARRATOR: The produce comes in from 80 countries.

They're being scanned here.

And then they go straight to the quality control tower.

This is the first control that is being done

when it comes to Norway.

NARRATOR: Inspectors screen the produce

for spoilage, as best they can, before sending it

to the supermarket.

The problem is we don't have very much time

to inspect the pallets.

It's maximum 60 seconds.

And also, due to the setup of the quality stations,

we are only able to control the two upper layers, maximum.

NARRATOR: That means, even with experience,

visual inspection only goes so far.

Inevitably, some spoiled produce goes undetected

and gets shipped along with the rest of the produce

all over Norway to local supermarkets.

PERSON: So our question was,

how can we check the whole pallets?

So that's when we started to look at the new technology.

The goal is increased freshness and reduced food waste.

If you can detect spoilage earlier in the value chain,

we are also able to do more

with the products that we might reject.

We can sort them, we can give them to food banks.

NARRATOR: BAMA connected with Tunable, a small tech company in Oslo,

inventors of an artificial nose,

or machine olfaction device,

that is already in use monitoring

the amount of greenhouse gasses

emitted by container ships.

Tharindu Madduma is Tunable's business development manager.

MADDUMA: BAMA came to us.

They explained that they had this problem

of determining the quality of the fruits and vegetables,

being able to do it at a large scale

and being accurate.

VALERO-CUEVAS: There's a long history

of inventions

that allow us to extend our senses.

So we've done that for sight.

We've done that for hearing.

MADDUMA: So, we have microscopes, we have hearing aid,

but smell is still a sense

that we haven't digitalized.

And that's what we're doing.

NARRATOR: Kristian Hovet is Tunable's C.E.O.

HOVET: When you take a breath,

you're doing a multi-gas analysis.

You're pulling in molecules,

and those molecules are detected by your nose,

and then it's detected by your brain

to tell you what you're smelling.

NARRATOR: The challenge for Tunable

was to take their existing analyzer for emission analysis

and increase its sensitivity

without making the device too big and cumbersome

to be useful on a warehouse floor.

So why use smell?

Our noses are sensitive detectors,

able to identify a wide variety

of chemicals in the air, even at low concentrations.

Airborne molecules can also potentially reveal

what's hidden in the pallets.

These molecules tell a chemical story

of fruits and vegetables as they rot.

But the device would have to be far more sensitive

than a human nose, and able to detect spoilage

more reliably than a human eye.

Produce, like all living things,

decays after death

as microbes consume dead cells,

releasing volatile organic compounds.

In theory, the team should be able to tune their machine

to recognize those molecules.

We knew that we could look at complex gasses.

We redesigned emission analyzer, and then we started testing.

NARRATOR: Eivind Jülke Røer

is the lead engineer on the Tunable e-nose project.

RØER: So now I'm going to measure fresh grapes

and then some spoiled grapes.

See our e-nose can smell the difference.

I'll start with collecting

a sample from the ambient air

as a baseline for the measurement.

(machine whirring)

And the noise you can hear now is actually the compressor pump

pulling air, uh, into the analyzer.

So now I'm going to take a sample from the fresh grapes

to see if there is anything present there.

NARRATOR: The probe pulls in air

and then compresses it

by a factor of five,

which increases the density of the sample

and makes molecules easier to detect.

Next, infrared light shines through the sample.

The light then passes through a chip

that sorts different types of molecules

based on the specific wavelengths

of light they absorb,

which ultimately allows the analyzer

and accompanying software to reliably detect

the presence and concentration

of molecules that signal spoilage

with extreme sensitivity.

RØER: The reading I got now

doesn't really show any molecules present at all

compared to ambient air,

which is more or less what I would expect from fresh fruit.

(machine whirring)

So now I'm going to take a sample

for the, um, spoiled grapes.

We see a clear difference.

We see up to 12% absorption

at ethanol wavelength, which is a good indication

that we actually smell the rotten grapes.

So, uh, this looks really promising.

HOVET: The fumes we were able to collect,

we were able to see the, the kind of the signatures.

NARRATOR: The engineers then tested

different kinds of fruits and vegetables

as they decayed, building up a database of chemical profiles.

HOVET: We saw a tomato was different, somewhat, from a banana.

Grapes were different from avocado, for example.

And we thought, well, this must be interesting.

(laughs)

(compressed air can sprays)

NARRATOR: Thor Bakke

is the founder and Chief Technology Officer of Tunable.

He's been working with microelectromechanical systems

for over 30 years.

BAKKE: Tunable is a component, uh, inside our analyzers.

That's the Tunable filter.

It's used to change the wavelength of light

so we can scan the wavelength and do spectroscopy.

(radio playing static between stations)

Spectroscopy is very much like, uh,

tuning a radio to find a particular station.

The gasses are separated in the infrared spectrum,

just like radio stations.

And then you can basically detect each one of them.

So that's where the word Tunable comes from.

NARRATOR: After extensive fine tuning in the lab,

it's time for the very first field test in the warehouse.

STELTZNER: Sometimes you can't learn

about all of the variables

that will be involved in an engineered system

sitting on a desk

with a pen and paper or at a computer screen.

You need to go out into the field.

You need to put it in the actual environment

and see how it interacts, learn from that, make changes,

and move forward.

RØER: Now I'm capturing; I'm in there.

Now I'm ready to do the measurement on the grapes.

NARRATOR: Eivind watches the screen,

waiting to see the telltale grape waveform.

But the pump just whirrs away.

And eventually he gives up.

Uh, I don't really know what happened here.

Uh...

For some reason, um, the results wasn't as expected.

NARRATOR: The first time definitely wasn't the charm.

Murphy's law.

Yeah.

HOVET: We know that it works in a laboratory environment.

So the big thing now

is showing that it actually works...

(chuckling): ...in real life, and as you see, there's been some challenges.

CHACHRA: We tend to think of failure as a bad thing, right?

That something that is not supposed to happen, happens.

But if you're doing anything new,

failure is an integral part of the process.

And the reason for that is because we can't

perfectly predict or understand how things are gonna work

in the real world until we try them.

NARRATOR: Turns out the warehouse temperature,

a chilly 41 degrees Fahrenheit,

affected the test result.

HOVET: The cold part.

We did know that it was cold in that area,

but did we take it on account enough?

No, we didn't.

We should, of course, have thought about that.

But, uh, but that's the kind of the learning,

that's the process.

NARRATOR: Back in the lab,

the Tunable team recalibrated their chip

to account for the BAMA warehouse temperature.

They also adjusted the design

to include the pumps that compress the sample,

increasing the density of the gas

to compensate for the lower metabolic rate

of the food in the refrigerated environment.

RØER: It will be really interesting to see

if the alterations we have, uh, made,

will actually do the difference in the field.

NARRATOR: Eivind is back with the latest iteration of the e-nose.

Further testing in the lab

showed that, even with the changes,

the machine needs time to adjust to the conditions

in the warehouse.

RØER: Now, I'll let the instrument stay here for the night

to reach a steady temperature,

and then we'll do measurements tomorrow.

♪ ♪

Well, after a long cold night,

the system should be ready to go.

(machine whirring)

Now we see absorption of light

at more or less 9.5, ten microns,

which, um, indicate ethanol being present.

This really shows that our new chip is working

in this real environment.

NARRATOR: Eivind uses the e-nose

to sample the air from various locations

on the entire pallet stack.

RØER: Actually, we see a spike at the ethanol absorption wavelength,

so that might be something.

NARRATOR: They've taken an important step.

A successful real-world test

of the newest version of the Tunable e-nose.

I'm not the most excited guy, but, um...

(giggles)

...this is, uh, this is exciting.

(e-nose humming)

I expected it, although you never know.

It's a big win.

I get very excited when technology works.

NARRATOR: Still, there is work ahead to make the technology viable

and, most importantly, scalable.

MADUMMA: We hope that we can make them more efficient.

Food waste is enormous global problem.

8% of all greenhouse gasses comes from food waste.

So if we can be a part of the solution, it's huge.

NARRATOR: Reducing food waste is one of many ways

engineers are trying to slow climate change.

But the negative changes we've made to our climate

are already damaging some environments

like coral reefs.

MOONEY: Coral reefs are in decline.

So one of the things that I really think about

is how do we fix the environment

that's sort of dying in front of us?

NARRATOR: Healthy coral reefs can be stunningly beautiful

and play a critical role in coastal ecosystems.

They harbor a tremendous diversity of marine life

and contribute to the overall health

of the world's oceans and their coastlines.

A quarter of all marine species depend on them for survival.

They're also important to humans.

Often located in shallow water,

they can protect coastal communities

from damaging storm surges.

And the reefs host a primary, sustainable food source

for hundreds of millions of people around the world.

But as the oceans warm,

corals are struggling to survive.

Excessive heat drives away the microscopic algae

the coral depend on.

That leads to a dramatic loss of color,

known as coral bleaching--

a powerful visual indicator of an unhealthy reef.

But bleaching isn't the only indicator of a reef in peril...

MOONEY: Not only it looks brown

and is lacking these beautiful, vibrant colors,

but it just sounds dead.

(underwater ambient noise)

NARRATOR: That's where sensory biologist Aran Mooney comes in.

MOONEY: My background is in hearing and in bioacoustics.

And I study how animals perceive the world around them.

(wildlife chittering)

Coral reefs are kind of rainforest of the sea,

and just like a really rich forest

might have a lot of birds calling,

and you might hear the monkeys calling in the background,

coral reefs are really the same.

So basically a healthy coral reef

has a really healthy rich soundscape.

(crackling, snapping)

NARRATOR: Snapping shrimp, lobster, and fish

create a symphony indicative of a biodiverse community.

MOONEY: And a degraded coral reef is just an impoverished soundscape.

It sounds quiet, kind of desolate.

So, by listening to the soundscape,

we can kind of track that biodiversity

and understand when that change is happening.

♪ ♪

NARRATOR: Off the coast of St. John in the Caribbean,

a team from the Woods Hole Oceanographic Institution

in Massachusetts

conducts bleaching surveys,

finding evidence of degraded reefs.

(water splashing)

To your right, there's some bleached coral.

You knew there's going to be bleaching here, right?

But then it's freaking everywhere, right?

YOGI GIRDHAR: I've been coming here

five or six years now,

this was the first time

I have seen such bleaching.

NARRATOR: Yogi Girdhar is a roboticist

and computer scientist at Woods Hole.

GIRDHAR: I am working on

robots and A.I.

and machine learning-based techniques

to understand complex ecosystems in the ocean,

such as coral reefs.

NARRATOR: A question they pose:

is it possible to build a robot

that can seek out and find healthy reefs

on its own? (electronic beeping)

If they succeed,

the robot could provide an efficient and cost-effective way

to find healthy coral reefs, map them,

and monitor their health.

(electronic crackling)

The soundscapes recorded by the robot

could be a vital tool in diagnosing reef health

and tracking decline or improvement.

♪ ♪

MOONEY: Good job, team!

♪ ♪

NARRATOR: The team has been collecting data on reefs

for over a decade.

You're going through this. Yeah.

I might be able to thread it through here.

NARRATOR: They have mountains of information;

including audio and video.

They've even created 3D models of the reefs

for further study.

Helping them gather this data

is this third-generation robot.

GIRDHAR: We call it CUREE--

C-U-R-E-E.

It stands for Curious Underwater Robot for Ecosystem Exploration.

NARRATOR: It's equipped with sensors, microphones, and cameras

and is still very much under development.

GIRDHAR: The design of a robot

is always evolving.

Our robot is never finished.

NARRATOR: It's an engineering challenge

with a lot of moving parts.

So they've broken it down into many small steps.

MARIA YANG: There are many, many problems

that you can solve with an engineering solution.

But I think you have to

really understand what the problem is

and sort of pick the two or three

that really you want to address.

Otherwise, you kind of fall into this trap of

trying to solve all the problems all at once

and you run out of resources.

♪ ♪

NARRATOR: This morning, the team is prepping for its latest test

right off the dock.

MOONEY: All right, Dr. Girdhar.

Are you ready?

Always.

GIRDHAR: I'll manage the tether. Got it?

NARRATOR: To start, they'll place a speaker on the ocean floor,

playing a recording of a healthy coral reef.

A sound file they captured

from a previous trip.

SETH McCAMMON: It should be on.

GIRDHAR: Yeah. All right.

We hear it.

(electronic crackling)

NARRATOR: They're hoping the robot

will recognize the sound through the water

and be able to record it.

In this outing,

the robot is not moving autonomously.

Researcher Seth McCammon

is operating the robot remotely

to steer and position it for the test.

I'm getting it in line with the thing

so we can start to look at the data.

GIRDHAR: If the robot doesn't work with this sound,

it's probably not going to work on the real coral reef,

so it's a good, good test.

NARRATOR: Experimenting with sound underwater

is not a new idea.

In the 1800s,

a Swiss physicist and a French mathematician,

armed with a bell and stopwatch,

measured the speed at which sound traveled underwater.

On one side of Lake Geneva,

Charles François Sturm rang a submerged bell,

(bell ringing) while Jean-Daniel Colladon

used a long tube to listen underwater across the lake...

(watch clicks) ...pressing his stopwatch

to keep track of how long it took

the sound to travel across.

Surprisingly, they found that water

is a better conduit for sound than air.

Sound travels through water

roughly five times faster.

Today, the Woods Hole team

will be using the speed of sound underwater

as part of their calculations.

The robot is equipped

with four microphones designed for underwater use

called hydrophones.

As the sound from the speaker speeds through the water

in all directions,

it reaches the hydrophones at slightly different times--

just milliseconds apart.

The researchers look at a computer display

that shows the signals recorded...

(electronic chirping) ...on each hydrophone.

McCAMMON: And so it will hit one hydrophone before the others

and by looking at the relative time of arrival

at those different hydrophones,

we can figure out which direction it came from first

and then steer the robot in that direction.

♪ ♪

NARRATOR: The robot correctly identifies

the direction of the sound--

an important first step toward autonomous navigation.

♪ ♪

A small but important victory.

♪ ♪

McCAMMON: It's like you're building out of LEGOS

and you're building up a house,

brick by brick by brick.

And it only works

when the house is fully done.

But you need to know

that each single brick in that

works on its own in isolation

before you're willing to add it to the larger picture.

MABRY: And so, you have this massive goal

that you're trying to achieve,

but there needs to be attainable goals along the way

because ultimately,

you're dealing with a system of components,

a system of elements

that need to work together

in order for this

to be successful.

NARRATOR: CUREE is ready to step up

to a bigger challenge.

Locating an actual healthy reef by sound--

something less predictable than what the speaker provided.

One of the healthier reefs in St. John

is in nearby Joel's Shoal.

GIRDHAR: I propose we drop the robot

like 20 meters...

MOONEY: We're like ten meters

off the reef right now.

NARRATOR: They'll place CUREE

approximately 20 meters from the reef.

(electronic chirping) To succeed,

it just needs to orient itself

toward the sound.

Robot going in.

All right, cast away! (electronic melody)

McCAMMON: So the test today

is mostly just trying to figure out

if the robot can accurately determine

which direction the reef sound is in.

NARRATOR: It's a more complex test.

This time CUREE is untethered

and the boat is drifting with the ocean current.

NARRATOR: If they lose contact,

they could easily lose the robot entirely,

and all of the engineering that went into it.

♪ ♪

MABRY: When they began to design this autonomous robot

that would go underwater,

there is a need to make sure that

this thing is able to behave

in an environment where, if it doesn't,

we can retrieve it...

NARRATOR: CUREE locates the direction of the healthy reef.

Which is encouraging.

NARRATOR: It's another successful test.

(electronic crackling)

The next big hurdle,

can CUREE not only locate,

but then move towards a healthy reef autonomously.

This will be a crucial milestone in the mission,

which is to ultimately build a fleet of robots

to map, monitor, and record

the health of corals around the globe.

While reefs are under serious threat all over,

there are some signs of hope,

and some surprising ideas for ways to protect them;

including one that came from this team's research.

♪ ♪

In their work, they discovered that the sound of a healthy reef

might actually have an indirect healing effect

on a stressed reef.

It has to do with the coral animal's life cycle.

Newly born baby corals--

tiny larvae-- drift in the ocean,

searching for somewhere to settle.

It turns out the sound of a thriving coral reef

signals them to settle into place.

Once they find a spot,

they can be very resilient

and grow for centuries.

So the more larvae a reef can attract,

the healthier it will be.

And that gave the team an idea.

We know these reefs are degraded

and we want to rebuild them

by attracting the larvae, the baby coral.

NARRATOR: In a past experiment,

the team found that larvae

could be drawn to recordings of healthy reefs.

So by placing speakers in strategic locations,

they could give a boost where it's needed most.

MOONEY: And that system actually

leverages the healthy landscape

and plays it back into the environment

and the idea is that it induces coral larvae

to kind of choose that environment and settle.

NARRATOR: The result?

Up to seven times more larvae settlement

compared to a degraded reef

without the audio boost.

A very encouraging sign.

♪ ♪

But back to St. John and CUREE.

The team is ready for the final test of the day.

McCAMMON: The robot is going to use the direction

that it's finding from its hydrophones

and then drive itself

to whatever the nearest acoustic source is,

which we're hoping is going to be Joel's Shoal Reef.

NARRATOR: This time, since CUREE will pilot itself,

it's tethered for safety.

They put CUREE in the water and give it the green light.

NATE FORMEL: Are we expecting it

to be moving or not? McCAMMON: We are.

NARRATOR: It looks at first as though it's orienting

toward the sound of the reef.

It thinks it's moving.

NARRATOR: But after a few minutes it's clear

that CUREE isn't making much headway.

It's just dumb stuff in the way that I wrote.

NARRATOR: It seems there's an issue with the software.

♪ ♪

All right, bring it back.

(ratcheting)

It's coming up.

FORMEL: I can now see it.

NARRATOR: They're starting to lose the light.

It's getting dark. (indistinct chatter)

NARRATOR: They weren't able to check off everything

on the day's to-do list,

yet they remain upbeat.

GIRDHAR: Overall, I am happy right now because...

McCAMMON: We ended the day with as many robots

as we started the day with.

NARRATOR: It's frustrating in the moment,

but they're making progress.

STELTZNER: The creative act of engineering

has got disappointment,

has got failure,

and that's how we learn.

(chuckling): So, it is a big ball of, of...

...two steps forward and one step back.

When you have a very massive "Why"

and a very massive purpose for what you're trying to do,

such as save the coral reefs,

it allows you to experience the disappointment

but not be defeated by it,

and continue to try the process of moving it forward.

♪ ♪

If you're not failing you're not trying hard enough.

(voiceover): Yeah, it's very frustrating

but when it works,

it's very satisfying.

NARRATOR: Engineering solutions to the climate crisis

will require creativity, innovation,

and a global commitment to making smart choices.

But we face many other challenges as well;

like restoring balance to the land

after decades of industrial pollution.

♪ ♪

On Navajo land in Arizona,

an Indigenous artist and engineers are collaborating

on a unique, local approach

to purifying contaminated drinking water.

(birds chirping) This pristine-seeming landscape

conceals a serious problem.

30% of the population in the Navajo Nation

lacks access to clean drinking water.

Decades of uranium mining

has polluted the land.

The United States government

used the heavy metal

to develop the atomic bomb

and power its nuclear weapons program

after World War II.

CHACHRA: When we think of engineering,

people are suspicious of it because,

for a good part of the 20th century,

one of the stories of engineering

was engineers making decisions about systems

that affected a lot of other people.

And often those effects were not positive.

NARRATOR: Byproducts of uranium mining,

such as strontium,

can mimic calcium in the body,

causing it to be absorbed by bones.

The E.P.A. has awarded $3.8 million

to support three drinking water projects

to benefit the Navajo Nation.

Some are proposing other, more homegrown solutions, as well.

(stone grinding)

Deanna Tso is a third-generation

Navajo artist who works in clay.

TSO: People always ask me,

"When'd you learn how to do pottery?"

I always say,

"I was born making it."

Both my parents, my mother and my father,

both did Navajo pottery.

(car doors closing)

NARRATOR: She has been collaborating with scientists

Navid Saleh and Stetson Rowles...

(knocks on door)

Hey! Good morning.

Hey, Deanna.

NARRATOR: ...on a project meant to address

the water contamination problem

on a very human scale.

SALEH (voiceover): I believe that engineering without people

is destined to fail.

Good. Good. Long drive.

SALEH (voiceover): There is this experiential knowledge,

knowledge that is housed within people's lives,

yet to be unlocked.

NARRATOR: Not all people here use

or have access to municipal water,

so the goal is to call upon local knowledge

to find a sustainable way to purify water

closer to the home.

YANG: We often think

of engineering as only being

the latest and greatest technology.

But, people have practices that are very effective now

and, and have been for,

you know, decades, centuries longer.

And so what can we learn from those, existing approaches

that are already effective?

So Deanna, this was something that...

NARRATOR: On this trip, the scientists want to build

a new prototype clay filter

for use in household water containers.

The hope is to integrate locally sourced minerals

so that the finished filter will remove uranium byproducts,

like strontium, from the water.

SALEH: Could you actually make something like that?

Do you have something similar?

I have one that I make

with the cone shape.

NARRATOR: Navajo potters like Deanna

use a local tree sap as a glaze.

Navid and his team wondered if the sap could be used

as part of a decontamination filter.

SALEH (voiceover): What we found was how much knowledge

the Navajos already had about the sap.

They already knew it has health benefits.

So this is a printout of the...

NARRATOR: Navid and his team recently conducted tests

that translated Indigenous knowledge

into the language of biochemistry;

quantifying the extent of the sap's antimicrobial properties.

Now, they hope to expand the filter's capabilities

to radioactive contaminants.

YANG: They worked together, collaboratively,

to make something new and better

that serves her community in a really, powerful

and very collaborative way.

We can engineer a shape or a design

that's going to work well, not only to filter water,

but people will want to use.

(voiceover): We see this amazing opportunity

to be able to use pottery,

or ceramics, as filters,

because it's so a part

of people's everyday life.

Particularly in places like the Navajo Nation

where traditional practices are so important.

TSO: Okay.

ROWLES: Which way?

NARRATOR: Navid and Stetson want to learn the process of making pottery

the way Deanna's mother taught her--

because collaboration is strongest

when it is truly interdisciplinary.

TSO: Yes.

You see that gray spot?

NARRATOR: Deanna starts from scratch,

harvesting clay from a rocky outcropping

on Navajo land.

Okay, so this portion is what?

That portion is clay. Okay.

SALEH (voiceover): We often as scientists believe

that we know a lot.

But we forget,

science as a discipline

has only been around for 500 years.

NARRATOR: There are many ways of generating knowledge

besides the modern scientific process.

CHACHA: These are all different ways

in which we interact with the physical world.

That diversity gives you new ideas.

And thinking about how to put together

old technologies and new technologies

might lead to entirely new paths.

It creates a symbiotic effect,

because the more people feel included

in what is being produced by something,

the more people see themselves being a part of

the producing of that thing.

NARRATOR: Next-- they source sap from pinyon trees.

There's one right here, let's check this one.

♪ ♪

(crunches) ROWLES: Whoo!

We hit the jackpot with this tree.

TSO: We were blessed for the day.

Come on in. (keys jangling)

I usually just take this much out.

NARRATOR: Deanna demonstrates how to grind minerals

into the fine grains that make up her clay.

One of you want to go ahead and give it a try?

ROWLES: I think there's a lot of engineering

that goes into creating pottery.

The freedom that it allows to make any shape.

(squeaking)

STELTZNER: The fusion of art and engineering.

Or maybe even the boundaries between art and engineering...

...perhaps they don't exist.

Perhaps they're really the same thing,

painted with a different palette.

NARRATOR: Stetson and Navid are working with Deanna

to prototype a shape for the clay filter.

I don't know if you know Deanna,

but I've been making some pottery since high school,

and I made this shape to try and see

if maybe we can explore making some shapes together.

I made a shape similar to that...

...and it looks like this.

And we do make these traditional Navajo pipes.

Do you think you can make some grooves

similar to something like this?

Kind of like an accordion basically,

so it has the same surface area but in a smaller size.

♪ ♪

NARRATOR: Adding grooves increases the total surface area of the shape.

More surface area will mean more contact

with the water inside.

TSO: I'm going to show you

an option we have that we can try:

Coil. Yeah. Making a coil.

Making a coil.

♪ ♪

NARRATOR: Next, the new prototypes

need to be fired.

SALEH: We have been working with Deanna

for almost nine years now.

TSO: Make sure we have it covered nice and good.

SALEH: Working with her side-by-side

as an equal partner intellectually,

only opens opportunities that are more meaningful

than we scientists would ever find

sitting at our desks.

NARRATOR: The last step:

heat and strain the pinyon sap,

creating the microbe-resistant resin,

which acts as a glaze to coat the pottery.

And now, a new addition to the filter.

ROWLES: Can you grab the zeolite?

NARRATOR: The scientists are using powdered chabazite,

a type of naturally occurring zeolite,

found abundantly on Navajo land.

♪ ♪

Chabazite is a porous crystal

made of sodium, calcium, and aluminum silicates

that has the ability to trap

and absorb contaminants.

♪ ♪

Finally, Deanna applies the resin.

TSO: The pottery itself has to be hot.

The sap has to be hot.

NARRATOR: The team hopes the chabazite

will add function to the resin,

removing uranium byproducts, like strontium,

from any water that comes into contact with it.

ROWLES: Wow, the colors are beautiful.

♪ ♪

NARRATOR: Back at the University of Texas at Austin,

it's time to test their water filter prototypes in the lab.

We've got some of the clay.

NARRATOR: Using the materials

they sourced with Deanna,

the scientists create small clay discs...

ROWLES: ...try and just punch out,

a little disc like that...

NARRATOR: And coat them with the same chabazite-enriched resin.

These are tiny lab versions of Deanna's pottery.

To test the discs,

the researchers expose them

to strontium-contaminated water

to see if the resin will successfully absorb

the uranium byproduct.

♪ ♪

If the filter works as expected,

the chabazite will capture strontium from the water

through ion exchange as the water passes through.

♪ ♪

ROWLES: Hey, Andrei. ANDREI DOLOCAN: What's up, bud?

Here's the sample.

Yeah, thank you.

NARRATOR: Senior research scientist

Andrei Dolocan

loads a sample into an ion mass spectrometer.

It scans the sample

on the molecular level,

layer by layer, over several hours.

When it's done,

the result is a map of the elements

within the scanned sample surface.

When the clay disc is completely scanned,

it's time to check the results.

This is the strontium signal.

NARRATOR: The data show that the strontium is found

in the same places as chabazite in the resin...

DOLOCAN: We have the zeolite, obviously sodium,

aluminum-silicon.

Uh-huh. DOLOCAN: Okay.

And now the, strontium is increasing exactly like...

NARRATOR: It's an encouraging sign

that the chabazite is working as expected

when used with Deanna's pottery technique.

SALEH: So I guess it was a really,

successful run, Andrei.

Yeah. We can see association

of strontium with the zeolite.

DOLOCAN: I agree, this is a good start.

ZILEVU: One thing that I've learned

from the research and design process

is that kind of doing

co-creation activities with the end user,

it's really a way to kind of bridge and create

new, innovative process,

because you're bringing the people

who are using the technology

throughout the whole journey.

So this is the one that Deanna made...

NARRATOR: Now a few steps closer to their goal,

the researchers will work

to incorporate Deanna's spiral

and the chabazite's filtering power

into their final design.

So moving forward,

I think the most difficult engineering challenge

is yet to come.

And I think it's going to be

translating our results from,

you know, a lab scale experiment

to something that's going to be usable

in households throughout the Navajo Nation.

♪ ♪

(birds chirping)

MABRY: At the end of the day,

we want to unlock human potential.

And in order to unlock human potential,

we are not doing ourselves a justice

if we continue to only demand certain solutions

from a subset of our populations,

the more we can get more people included,

the more we can unlock

not just solutions to problems that we now see,

but things that are yet to come.

♪ ♪

NARRATOR: As we change our world through engineering,

it's up to us to make changes;

for all of us, by all of us.

ARMANI: I think we're all engineers.

We all build things,

we all design things.

(chuckling): We all break things

and then have to fix them

and put them back together.

NARRATOR: And we get to decide

what comes next.

What if we were to design this?

What if the world was to look like this

in 50, 100 years? What could that look like?

♪ ♪

ALI HAJIMIRI: The engineer's work is never done...

If you're not failing, you're not trying hard enough.

You can always create something new.

♪ ♪

NARRATOR: Building stuff

to change the world.

♪ ♪

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