Original subtitles

♪ ♪

NARRATOR: Earth.

Over eight billion people live here.

But not all of them are home.

Since the turn of the century,

a few have been living here...

♪ ♪

...in the most hazardous scientific outpost ever built:

the International Space Station.

♪ ♪

Altogether, over 280 people

have ridden a controlled explosion

250 miles into space,

risking their lives

to maintain a continuous human presence off planet.

One day, we may be getting ready for a spacewalk

and the next day, we'll be doing some world-class science.

♪ ♪

NARRATOR: Its unique environment provides a research laboratory

like no other.

But conducting science in space

brings its own challenges.

RAJA CHARI: Very quickly, you can have an out-of-control situation

from a very innocuous start.

♪ ♪

NARRATOR: As astronauts push

the boundaries of science and exploration,

they face daily threats.

(over radio): CO2 sensor bad.

MAN: Copy, Luca.

LUCA PARMITANO: You are constantly at risk of dying

for a multitude of reasons.

♪ ♪

WENDY LAWRENCE: You've got orbital debris

that can hit your module

and put a hole in it.

♪ ♪

CHRIS CASSIDY: In the military,

we say that problems happen

at the fold of a map and at night.

And that's exactly how this was shaping up.

ZEBULON SCOVILLE: How do we respond

to that unknown?

Understanding situations

may have the ultimate consequences.

(alarm beeping) MAN (over radio): Station, Houston on 2.

This is an actual.

NARRATOR: This is the story of innovation

and scientific exploration

aboard the I.S.S.

"Operation Space Station:

Science and Survival."

Right now, on "NOVA."

♪ ♪

NARRATOR: June 2024.

The world is gripped by a drama playing out far above Earth.

NASA astronauts Butch Wilmore and Suni Williams

had been scheduled to spend just eight days

aboard the International Space Station

while testing a new commercial spacecraft,

the Boeing Starliner.

WILLIAMS (over radio): Into the spacecraft!

NARRATOR: Instead, when the vehicle encounters technical issues,

their mission stretches into months.

Despite the difficulties,

the pair pivots to become routine crew members,

drawing from their years of training

and a deep love of the job

to embrace their extended mission.

Because this job is like no other.

We're still pioneers in space,

so there's still a lot that we have to learn.

(over radio): Okay, my yellow hook,

closed and locked.

NARRATOR: Space is incredibly risky.

The safest thing to do is to not go anywhere,

but that's not going to really teach you much

about your species or the planet you live on.

You have to take risk to get the reward.

NARRATOR: Butch and Suni's extended stay

is just the latest in a long line

of unexpected challenges faced in orbit.

MAN (over radio): And lift off.

The International Space Station

is underway.

NARRATOR: Since the space station's first module

was launched in 1998,

there have been countless moments of risk and uncertainty.

ROBERT CURBEAM (over radio): There's ammonia all over the place.

NARRATOR: Requiring calm and quick thinking to resolve.

TOM JONES (over radio): You just pulled the bail?

CURBEAM: Yeah.

And that stopped the leak.

NARRATOR: All to create a unique research laboratory,

a platform for international science and discovery

through cooperation,

uniting humanity in the pursuit of knowledge

beyond our planet.

♪ ♪

From monitoring hurricanes on Earth

to cultivating plants in space.

From detecting X-rays released by neutron stars

to developing cancer therapeutics.

RENITA FINCKE: We have taken technologies,

people, systems from all over the world,

and we've put it together into this amazing laboratory.

♪ ♪

The research that we've been able to do

has directly benefited life on planet Earth,

and we're only just getting started.

♪ ♪

NARRATOR: Every minute of an astronaut's day on the station

is carefully planned,

and life on board might even come to feel routine.

But it's always just a matter of time

before the universe finds a way to remind the crew

of just how vulnerable they are.

♪ ♪

In 2013, plans are underway to further extend

the International Space Station's scientific footprint.

A new module called Nauka,

Russian for "science,"

is to be added to the station the following year.

Created to conduct

materials science and biotechnology research,

Nauka includes a base for the European Robotic Arm

and will also feature a specially designed airlock

to carry out experiments in the vacuum of space.

♪ ♪

But to unlock this groundbreaking science,

astronauts must brave the most unforgiving extremes.

CASSIDY: In my personal operational experience in the military,

in the SEAL teams,

the bad guys were the enemy that's shooting at you.

In a space mission, the "bad guy"

is the environment.

♪ ♪

The environment is trying to kill you.

PARMITANO: Space is not really made for life.

It's very cold and very hot at the same time.

It doesn't have an atmosphere.

It really doesn't want to keep you alive.

NARRATOR: A spacewalk,

also known as an extra-vehicular activity, or E.V.A.,

is especially dangerous.

Astronauts usually go through the airlock in pairs

so that once outside,

they can assist each other if needed.

But still, they are isolated

and vulnerable to hazards like radiation,

micrometeoroid impacts,

and equipment malfunctions.

On July 16, 2013,

American astronaut Chris Cassidy

and flight engineer Luca Parmitano

don their spacesuits.

Spacewalks are not something that you just

willy-nilly do-- "Hey, it's Tuesday.

You want to go out and knock out a spacewalk?"

No, it doesn't work like that.

Takes about four hours

to go through the oxygen pre-breathe process

and all of the checks leading up

to opening the hatch.

(over radio): All right, I have a waist tether,

gate closed and locked.

(voiceover): All spacewalkers

are tethered to the space station

with a retractable metal cable

that pays out to 85 feet.

And just like if you walk a pair of dogs on dog leashes,

those leashes get all tangled up.

PARMITANO (over radio): On my way.

CASSIDY (voiceover): Safety tethers are no different.

So, oftentimes,

we intentionally take separate routes,

so the safety tethers

don't tangle up on themselves.

NARRATOR: Luca and Chris come together

on top of the Tranquility module

to carry out their task:

connecting data and ethernet cables

for when the new module arrives.

38 minutes into the E.V.A.,

a warning alarm is triggered in Luca Parmitano's spacesuit.

The carbon dioxide levels are too high.

PARMITANO (over radio): CO2 sensor bad.

MAN: Copy, Luca.

It measures 48.6.

CASSIDY: Copy that, Luca.

(exhales)

NARRATOR: Ordinarily, exhaled carbon dioxide

would be controlled and removed

by the Portable Life Support System

in Luca's backpack.

The alarm could signal

a dangerous buildup of the gas

inside his spacesuit,

which could lead to severe headaches,

impaired judgment,

and even death.

PARMITANO (voiceover): We have a checklist

telling us to check different parts of the suit

to understand whether it is an actual alarm

or whether the sensor itself is at fault.

CASSIDY: It said, "Did the reading go from normal

to ludicrous instantly?"

If that happened, then it's probably the sensor's bad.

MAN (over radio) And Luca, nice work on the cuff checklist,

but no further action on your part.

NARRATOR: Doubtful of the carbon dioxide reading

and satisfied that Luca has no symptoms,

Mission Control concludes that the sensor is faulty,

and the E.V.A. can continue as planned.

(static hisses)

But six minutes later,

Luca calls Mission Control again:

there's another issue.

PARMITANO (over radio): F.Y.I.,

I feel a lot of water on the back of my head.

MAN: Are you sweating? Are you working hard?

PARMITANO: Um,

I am sweating,

but feels like a lot of water.

MAN: Yeah, Luca, we copy. MAN: Copy.

PARMITANO: Just F.Y.I.

(voiceover): There should never be

any water inside your space suit,

especially not in the, in the helmet area,

and so I communicated that to the ground.

(chuckling): And I said, "I don't think it's a big deal."

I just wanted to keep going with the E.V.A.

MAN (over radio): Hey, Luca, while you're working there,

can you give us, uh,

maybe some more words on the water?

Um, maybe identify the source, do you think,

and then, is it getting any worse

or is it the same?

PARMITANO: Um, good questions.

It's still the same,

and I cannot tell you the source.

NARRATOR: On Earth,

water falls under the force of gravity.

In space, it's much less predictable.

CASSIDY: It's surface tension

that drives the behavior of water.

That surface tension is a pretty strong force,

and the water just wants to stick

to whatever it's stuck to.

NARRATOR: In Luca's case,

the unexplained ball of water

is sticking to the back of his head

and threatening to creep around toward his face.

PARMITANO: My biggest concern

was the water getting inside my ears.

(static hisses)

Because if it did, it's really hard to get it out.

You cannot tap your head-- there's nothing you can do.

(static hisses)

CASSIDY: I finished what I was doing

and got over close to him, and I remember,

I could see, it looked like

half of a grapefruit just kind of jiggling

on his head.

(Parmitano panting softly)

CASSIDY: And then little bitty pieces

of water droplets moving around inside.

(on radio): I see beads of sweat.

PARMITANO: No, it's not sweat.

CASSIDY: Oh, it's not sweat.

MAN: Hey, Luca, can you clarify,

is it increasing or not increasing?

PARMITANO: It's hard to tell,

but it feels like a lot of water.

CASSIDY: Oh, I see, yes.

I see it now, wiggling.

PARMITANO: And, um, I, I can't, don't understand

where it's coming from-- it can't be the water...

CASSIDY: It has to be the bag.

NARRATOR: At the European Space Agency,

astronaut instructor Hervé Stevenin

watches a live feed of the mission.

(Stevenin speaking French)

(translated): They thought it might be

the small water bag that the astronauts carry.

There is a small bag

which is attached to the stomach with Velcro

and contains around one to one-and-a-half liters of water.

This has a little straw,

to enable the astronaut to stay hydrated.

CASSIDY (over radio): And you've sucked it dry?

PARMITANO: Okay, the bag is dry now.

NARRATOR: But the situation doesn't improve.

CASSIDY: The bag is empty now.

And, uh, you know, there's something

less than a liter in the back of his head.

800 milliliters, maybe.

MAN: All right, Chris.

NARRATOR: More water collects in Luca's helmet.

PARMITANO: Yeah, I'm thinking that it might not be the water bag.

The only other option, Chris, that I'm thinking

is the LCVG.

NARRATOR: The LCVG,

or Liquid Cooling and Ventilation Garment,

circulates cold water in the spacesuit

via a system of tubes

to prevent astronauts from overheating.

As Chris and Luca correctly suspect,

Luca's LCVG has malfunctioned

and is leaking water into his helmet.

The very suit designed to protect him

from the dangers of space

may now be putting him in mortal danger.

CASSIDY: That's the moment, I think,

where it solidified in everybody's mind,

"Okay, we're done for today."

NARRATOR: 67 minutes into the E.V.A.,

Mission Control terminates the spacewalk.

MAN (over radio): All right, Chris and Luca, just for you guys,

we think we're are gonna terminate E.V.A. case for EV2.

So, Luca, we'll have you head back to the airlock.

Chris, we'll get a plan for you

to clean things up here

and then join him in a minute.

NARRATOR: Luca needs to get back inside the space station

and remove his helmet.

He begins retracing his route

back to the airlock,

while Chris clears away their tools.

PARMITANO: I remember leaving Chris,

and as I made the corner and disappear from sight,

I remember thinking

that I really wish that Chris could come with me,

because that's how we train.

We train to be together-- that's why we go outside

as a team, so that we have each other's back.

CASSIDY: Before I saw Luca disappearing

behind the Z1 truss...

And I wanted to say out loud,

"Luca, stop, hold on, I'm coming with you."

It just felt like that's what we should do.

NARRATOR: But as tempting as it is to hurry,

Chris follows orders

and forces himself to move deliberately.

In the military, we say that problems happen

at the fold of a map,

at the junction of grid squares,

and at night.

And that's exactly how this was shaping up.

As soon as he started to move,

the sun set.

PARMITANO: And everything turns gold, bright gold,

for one split second.

Incredibly beautiful,

and then it's lights out.

(static hisses)

(static hisses, water drips on radio)

NARRATOR: The I.S.S. takes around 90 minutes

to orbit the Earth.

For half this time,

the space station is in total darkness.

(static hisses, water drips on radio)

CASSIDY: Now, once Luca started to move,

well, what happened to his motion,

it gets transferred into the water, too,

so that stationary jiggly ball of Jell-O

starts flushing around his head.

♪ ♪

PARMITANO: I felt it coming closer and closer to my forehead

and I thought, "Okay, this might cover

"both of my ears at the same time.

"It may be more than a simple hindrance.

It may be an actual, an actual problem."

And I just completed a maneuver

where I put myself upside down,

so all my terms of reference

had completely switched 180 degrees.

That's when the water really completely covered my nose...

...and I found myself isolated,

unable to see anything,

unable to breathe through my nose.

I didn't really know how much time I had

before the water reached my mouth.

NARRATOR: If too much water covers both Luca's nose and mouth,

he'll be unable to breathe

or drink his way out of trouble.

(radio static hissing)

And to make matters worse,

water enters Luca's comms,

causing it to malfunction.

PARMITANO (over radio): Hey, Chris?

CASSIDY: I hear you, Luca, go ahead.

(radio static hissing)

Luca, I hear you. PARMITANO: Chris?

Yeah...

(radio static hissing)

(translated): There are two mics here, and when Luca talked,

all we could hear were gurgling sounds.

This was terrifying to hear for us here in the control room.

At this stage, we realized

that something serious had happened,

very bad and very dangerous.

(water bubbling)

My memories are of just

trying to feel around,

making sure that I would grab the correct handles

in a pressurized glove,

which gives you no feedback, no tactile feedback.

And I called Chris, telling him,

"Hey, Chris, I, I think I'm a bit lost,"

but nothing came out,

and I, I didn't have any return in my earphones,

so I knew that he couldn't hear me.

(water bubbling)

And at the time, my thoughts were,

"Okay, I don't think Chris is going

"to come and get me right away.

How much time do I have?"

That was my thought in my head.

"How much time do I have

before this helmet fills up with water?"

There was a risk

that if the water increased dramatically,

I would drown in space.

NARRATOR: For the next five minutes,

Luca will be completely silent and alone.

♪ ♪

(water drips)

CASSIDY: He had the amazing presence about himself,

when everything kind of went dark and silent,

to just stop.

(water bubbling)

NARRATOR: At that point, Luca remembers

he is tethered to the space station's airlock.

STEVENIN (translated): His cable extends

all the way along the route, creating a safety line.

If the astronaut were to float off into space,

this cable would slowly pull them back towards the airlock.

(speaking French)

CASSIDY: That tether has a little three- or five-pound pull to it,

and he waited to feel the direction of that pull.

And then he just put his hand over

and grabbed the next piece of metal that he could find,

and inched his way back that way.

Unbelievable awareness by Luca.

♪ ♪

NARRATOR: The gentle tug of the waist tether

leads Luca back to the airlock.

But he's not safe yet.

Before he can take his helmet off,

the airlock must be sealed and repressurized.

With no time to waste,

the I.S.S. crew runs through their checklist.

Five minutes later,

Chris joins Luca, squeezing in feet first.

CASSIDY: The only thing that mattered at that point

was the hatch being closed.

Because if we couldn't close the hatch,

we couldn't get good air pressure.

If we couldn't get air pressure,

we couldn't get Luca's helmet off,

and we can't get Luca's helmet off,

pretty soon, he's not going to have

air in his helmet to breathe.

NARRATOR: With Luca's comms malfunctioning

and water now obscuring his vision,

Chris must ready the airlock

before crewmate Karen Nyberg can repressurize it.

(man speaking faintly on radio)

As they speed through

the normally 15-minute-long airlock procedure,

Ground Control attempts to check in with Luca.

MAN (over radio): Hey, Luca, from Houston.

How you doing? Give us a status.

(water bubbling)

NARRATOR: But there is still no response.

CASSIDY: Luca, do you hear that?

(water bubbling)

NARRATOR: The pair are positioned head-to-foot,

making it difficult for Chris to see into Luca's helmet.

(static hissing)

CASSIDY (over radio): Shane, I don't think he can, uh...

His voice is going out or you,

he can't hear you, but...

I'm trying to see him.

Right about then, I grabbed his hand.

(over radio): Squeeze my hand if you're fine, Luca.

(static hisses)

Luca, squeeze my hand.

Everything okay?

You okay?

And we had never pre-briefed this,

never talked about it,

but I squeezed his hand.

(static hisses)

(over radio): Roger that.

Shane, visually confirmed,

he's doing okay.

♪ ♪

Sorry to my wife, but,

there'd been never a more comforting

squeeze back of a hand.

♪ ♪

That sensation of feeling his hand squeeze back

in a nice, controlled way

was, like, "Okay, we're going to be all right."

(over radio): He looks fine.

He looks miserable, but,

uh, okay.

MAN: Copy all, Chris, uh,

we'll just status you from now on to check on him.

(Cassidy's mic crackling)

CASSIDY: 14 PSI, Karen.

NYBERG: Hatch coming open.

(static hissing)

MAN: Airlock, Houston.

Uh, if you could have some towels ready,

that would be great.

NYBERG: We have them here.

PARMITANO (voiceover): As my crewmates from the inside

were opening the hatch, I looked up,

and I could see Karen, Karen Nyberg's face,

and Fyodor.

The whole crew had come into the airlock to help me,

and their faces,

they were so worried.

CASSIDY (over radio): Hatch is open, Shane.

Luca's going through the airlock.

MAN: Copy, Chris, thanks.

The sense of friendship, camaraderie,

it's a form of love that,

that we should explore more, I think.

♪ ♪

I could feel it, I could sense it,

I could see it on their faces, and I was moved.

MAN (over radio): Okay, Chris, just hang tight for a bit.

Once we get Luca taken care of, we'll work on you.

CASSIDY: No problem, I'm in no rush.

I got a ringside seat.

PARMITANO (voiceover): I was obviously relieved.

I knew that the ordeal

was just about to end

when they took the helmet off.

♪ ♪

I was all smiles,

and I started cracking jokes.

They were certainly happy to see me.

I was certainly happy to see them.

♪ ♪

NARRATOR: A thorough investigation

reveals that a clogged filter

led to the leak in Luca's suit.

To ensure that astronauts can keep breathing

if such a thing happens again,

NASA has an absorbent pad and even a makeshift snorkel

installed into each helmet.

♪ ♪

The way water behaves in space

is just one aspect of microgravity,

which is one-millionth the gravitational pull

experienced on Earth.

And it's what helps keep the space station in orbit.

♪ ♪

It's a challenge to live and work in microgravity,

but it also allows for groundbreaking studies

to be carried out on the I.S.S.

♪ ♪

Biomedical experiments in space

reveal that in microgravity,

protein crystals form more uniformly, with fewer defects.

JENNIFER BUCHLI: They tend to be higher quality.

They tend to be purer and larger.

And so, this has really been a great application

for the pharmaceutical industry.

NARRATOR: A team of Japanese researchers

has taken advantage of the I.S.S.'s Kibo laboratory

to investigate proteins associated

with Duchenne's Muscular Dystrophy...

...a severe genetic disorder

causing progressive muscle weakness.

BUCHLI: That series of experiments were really successful

in finding some of the crystals associated with those proteins

that they weren't able to do on the ground,

and develop drugs to target those.

NARRATOR: Other experiments focus on the astronauts themselves

and the impact the microgravity environment

has on their bodies.

A vital area of research

if humanity is to venture farther out into space.

And we give periodic samples of blood

and urine and saliva, and, in some cases, number two

to test all of the different outcomes on the body.

PARMITANO: We are both the conductors and the test subjects.

We don't like the term "guinea pigs"

because, uh, because we're not,

but we are subjects of the same, of the same kind of experiments.

♪ ♪

In the end, we are interesting in, what can we glean

from performing science on the human body in space

that we cannot on the ground?

♪ ♪

NARRATOR: Every part of the space station is crucial

to conduct this science

and maintain the lives of its inhabitants.

All the things we might take for granted here on Earth--

air, water, food--

have to be designed, calculated, and engineered

to work properly in microgravity.

Even using the toilet.

CASSIDY: Close the lid.

CASSIDY (voiceover): You gotta be able to use all of your facilities,

whether it's the bathroom

or the air conditioning or the water processor.

All of those systems are there for a reason,

because you need them.

Let's take a peek at the process.

NARRATOR: With so little gravity, space toilets use air flow

to pull urine and feces away from the body

and into the proper receptacles.

And this valve is what activates

the whole system.

(voiceover): Going number one,

you feel pretty confident with that.

You're effectively just turning on a fan,

opening a valve, and, and peeing.

In good NASA fashion, we have a checklist.

This is called procedure 2.301,

and in case things go wrong...

Going number two is a little bit more...

Yeah, you, you really reread every little line.

There's a plastic liner in there, where your deposit goes.

If you make the mess, you got to clean up the mess.

So you don't want to be that one.

You take this red tab, you pull it off the rim,

and we do have a, a stick, and you push it down in there.

And then it's time to put a new bag on.

Ready to go.

(toilet flushing)

NARRATOR: But the toilets are vital

to the International Space Station in more ways than one.

CASSIDY (voiceover): Water is life.

Water is life on Earth.

Water is life on the International Space Station.

Every drop of water,

whether it's your urination,

whether it's your sweaty T-shirt from exercise,

the moisture in our breath as we exhale,

all of that moisture gets captured

by the Environmental Control System

and put back into the water processor.

NARRATOR: This fundamental part of the space station's

Environmental Control and Life Support System

allows the I.S.S. to recycle 98% of the water

that a crew brings along at the start of a mission.

CASSIDY: Every now and then, as you're filling your coffee bag,

you think, "Wait a minute,

this was yesterday's coffee, and it's also today's coffee,"

but the, the system works really well,

and you get alarms long before

it, it is anything but pure water.

NARRATOR: While the systems on board are designed

to keep the crew alive,

it is the responsibility of the crew

to maintain the space station itself,

a fundamentally symbiotic relationship.

Neither could survive for long periods in space

without the other.

The I.S.S.

is the largest human-made structure in orbit ever built,

with a surface area of well over 100,000 square feet

exposed to the hostile environment of space.

One of the dangers in space that's outside the vehicle

are what we call micrometeoroids.

So those can come from a number of sources.

LAWRENCE: Bits of cosmic dust

traveling at a tremendously high speed

can hit the shell of your module and put a hole in it.

♪ ♪

NARRATOR: Impact tests conducted on the ground

reveal the destructive force of high-velocity particles,

some no larger than a grain of sand.

Incoming particles can reach speeds

of up to 162,000 miles per hour,

up to 50 times faster than a speeding bullet.

The I.S.S. has survived

several direct hits to its solar panels

and to the Canadarm2.

MICHAEL LÓPEZ-ALEGRÍA: The smaller pieces cause problems

because they're going very fast.

So you multiply a very small number, which is the mass,

times a very big number, which is the velocity,

that's where you get the problem.

NARRATOR: The result is that even the tiniest particles can pack

a huge punch.

To defend the space station,

more than 100 shields protect the critical components.

A common kind is a stuffed Whipple shield...

...a multi-layered system of metal and synthetic materials,

which can break up smaller meteoroids,

dispersing their energy.

KWATSI ALIBARUHO: Russian modules tend to have

thicker ribs and thinner skin.

So from a probabilistic perspective,

the Russian modules are much more susceptible

to small micrometeoroid penetrations.

On the flip side, the U.S. modules have

very, very thick skin.

So smaller micrometeoroids

are not likely to penetrate the U.S. module.

NARRATOR: But micrometeoroids aren't the only threat.

LÓPEZ-ALEGRÍA: Increasingly,

it's orbital debris that comes from something human-made.

So a screw, a paint fleck, a rocket body--

I mean, it could be anything, right?

LAWRENCE: There are so many more objects in space.

There may be bits of derelict satellites

that approach your orbit.

NARRATOR: With low Earth orbit becoming more crowded by the day,

the probability of catastrophic collision increases.

CHARI: The good thing about low Earth orbit is,

we've seen this huge boom

of private companies and commercialization,

and it's everywhere.

Now, the bad thing is,

there's lots of old pieces of stuff out there,

whether it's spent launch vehicles,

whether it's dead satellites.

NARRATOR: Protecting the I.S.S. now poses a unique challenge.

Today, more than 15,000 pieces of space debris

are tracked in low Earth orbit, where the I.S.S. resides,

including fragments of used rockets

and decommissioned satellites

that, with no way to regulate their temperature,

repeatedly expand and contract,

until they break up or sometimes even explode.

And these are just the objects we are able to track,

those larger than four inches.

Add in smaller fragments,

and the total number of debris particles

is estimated to be in the millions.

Each fragment can go on to hit more objects,

creating exponentially more fragments and more collisions.

A potential nightmare for Mission Control.

The bigger pieces we track pretty well.

And we do debris avoidance maneuvers sometimes,

because we know that there is a potential collision.

NARRATOR: In 2021, Russia launched an anti-satellite missile,

deliberately destroying one of its own defunct satellites.

The impact created a massive cloud of high-velocity debris

hurtling through low Earth orbit.

Although the initial pass missed the station,

the danger was far from over.

Subsequent orbits of the wreckage

required Mission Control to carry out avoidance maneuvers

to keep the I.S.S. out of harm's way.

But rogue impactors aren't always the problem.

Every maneuver, every docking,

is painstakingly planned and monitored

by the folks at Mission Control.

And during these tightly coordinated movements

of the space station,

controllers must be ready for the unexpected.

TRANSLATOR (over radio): The range is three meters.

(man speaking Russian)

TRANSLATOR: Range...

(man speaking Russian)

TRANSLATOR: ...is 0.1.

We're standing by for contact.

NARRATOR: July 29, 2021.

After years of delays,

the uncrewed multi-purpose laboratory module,

or MLM, Nauka

docks with the International Space Station.

It marks the first major expansion to the Russian segment

in over ten years.

Once docking to the Zvezda Service Module is complete,

at Mission Control in Houston,

Zebulon Scoville takes over flight director duties.

SCOVILLE: I did a quick handover and plugged in,

thinking that we were just going to be

doing some minor reconfigurations

and stabilizations of opening hatches,

equalizing the atmospheres, and so forth.

It didn't quite go that way.

About one-and-a-half minutes after plugging in my headset,

a small yellow stripe lit up across the caution warning board

in the front of Mission Control.

My attitude control officer

notifies me that we have a loss of attitude control,

or LOAC.

NARRATOR: For reasons unknown,

the I.S.S. has begun to spin out of control.

SCOVILLE: We saw on the front screens,

the video cameras coming from I.S.S.,

almost a snowstorm of particles

around the outside of the I.S.S.

And it wasn't entirely clear what the source of this was.

This could be

a coolant fluid that had vented,

it could be a fuel or propellant that was leaking overboard,

or it could be thrusters firing.

The fact of the matter is, we didn't know.

And so this is where we had to very quickly try to understand,

what is this venting overboard?

What is it doing to I.S.S.?

How will we, first, make sure this crew is going to be safe

and, second, get the vehicle under control?

MAN (over radio): Station, Houston on 2.

We need you in two decimal seven zero two.

This is an actual.

NARRATOR: French astronaut Thomas Pesquet and his six crewmates

are onboard at the time.

(speaking French)

(translated): "This is not training."

That's the message we don't really want to hear

during a six-month mission.

♪ ♪

SCOVILLE: If a space station spins too fast,

this could introduce several potential hazards.

If it were to flip upside down,

now our antennas, which are normally pointing

towards our communication satellites,

are no longer pointing up.

So we risk losing communication with the space station.

PESQUET (translated): We have solar panels that are

35 meters across and 70 meters long and very, very fragile.

The acceleration of rotating them

will generate centrifugal force,

and that can tear everything apart.

SCOVILLE: We have docking mechanisms

with the crew vehicles that are used as lifeboats.

If we spin too fast,

if we had to undock in an emergency,

those hooks might jam.

PESQUET (translated): It's really very, very dangerous.

A space station is very fragile.

It doesn't even have to carry its weight.

NARRATOR: The advantage of building a station in the vacuum of space

is that you don't have to fight things like wind and gravity,

so the structure can be less sturdy.

The problem is, any unexpected twisting

could break it into pieces.

Ground Control desperately needs to understand

what is causing the I.S.S. to turn.

SCOVILLE: So one of my first questions

was to my life support officer.

(over radio): Are we maintaining cabin atmosphere?

Cabin atmosphere is stable flight.

Okay, what about cooling systems?

Thermal systems are stable flight-- we're looking good.

NARRATOR: The team ticks off a checklist

of possible causes...

(man speaking on radio)

...until a plausible suspect emerges.

SCOVILLE: One of the main and most likely candidates was

that the Nauka module was firing thrusters.

NARRATOR: A software error on the Nauka

means that it doesn't recognize

it has successfully connected to the I.S.S.

(translated): And so it will try

to establish its orientation, to move,

to capture the sun, to recharge its solar panels.

The problem is, it starts to take the whole station with it.

NARRATOR: Nauka's thrusters start firing,

trying to pull away from the space station

it is now securely docked to.

MAN (over radio): Station, Houston on 2.

We are out of attitude by at least 45 degrees and increasing.

NARRATOR: Four huge gyroscopes on board the I.S.S.

keep the station in position.

As the Russian thrusters fight with the space station's gyros,

there's concern that the joints of the aging ship

can't take the strain.

So the decision is made

to shut the gyros down... (alarm beeping)

...reducing the stress on the attachment points

that connect the station's modules together.

The I.S.S. is now in free drift.

And there's an added complication.

SCOVILLE: Unfortunately,

the Nauka module could only communicate with the ground

if the station was physically over the Russian ground sites.

As it was, we were just heading off

of the eastern coast of Russia over the Pacific.

And so we had no insight, no telemetry, no data,

and no ability to command it or turn it off.

We weren't going to get that back for about 90 minutes.

NARRATOR: In Houston, flight controllers listen

to real-time translations of the communications

between Moscow's Mission Control

and the cosmonauts on board the station.

(people speaking Russian over radio)

TRANSLATOR: Oleg, please,

can, can you confirm or not

whether MLM thrusters are still firing?

Do you see,

do you hear anything?

(people speaking Russian)

TRANSLATOR: I can confirm that the thrusters are still firing.

They have just fired, and we could feel it.

(translated): At the time, I don't know if we fully realized

the seriousness of the situation.

♪ ♪

SCOVILLE: We've got one-and-a-half hours

to ride this thing out

before we're going to be able to completely stabilize the system.

At this point, in order to assure

we had every advantage we could,

I declared a spacecraft emergency.

NARRATOR: A spacecraft emergency

ensures that all attention is focused

on the operation at hand.

♪ ♪

All available ground antennas across the U.S.

now attempt to make contact with the I.S.S.

TRANSLATOR (over radio): Oleg, we did not copy your last.

Could you repeat your last?

NARRATOR: But still,

the connection between the ground and space

is patchy and unpredictable.

(people speaking on radio)

And, with the whole I.S.S. structure now turning away

from its communications satellites...

(people speaking on radio)

...U.S. operations are about to lose contact with the crew.

(alarm beeping)

SCOVILLE: We were tracking the space station spin,

and we could predict we had minutes

to communicate several steps of procedure to the crew

before we were going to run out of time.

PESQUET (translated): Step number one,

make sure to secure everything that is outside the station

that can move, that can rotate.

(man speaking on radio)

NARRATOR: The crew are instructed

to lock the station's radiators,

which are at risk of shearing off,

while the solar panels are repositioned.

♪ ♪

Meanwhile, at Mission Control,

the team formulates a plan

to fight back against Nauka's thrusters.

MAN (over radio): We want you to run the procedure...

♪ ♪

SCOVILLE: We knew, as the Nauka module's thrusters were firing,

that we had to bring

a bigger lever arm, a more powerful force,

to bear against these thrusters.

NARRATOR: For that extra muscle,

Ground Control turns to the Zvezda Service Module,

primary source for the I.S.S.'s propulsion systems.

At this time, a cargo ship, Progress 78,

is also docked to the station,

on the opposite side to the misfiring Nauka.

Crucially, both Progress 78 and the Zvezda have thrusters.

SCOVILLE: Now, typically,

there will be days of analysis.

In this specific case, this was unexpected,

and so there was a little bit of engineering judgment

that had to be applied,

recognizing that the alternative and indecision

would have been worse.

NARRATOR: Mission Control makes the decision to fire up

the Zvezda and Progress 78 thrusters

to set up an orbital wrestling match with the Nauka

that they have to win.

♪ ♪

MAN (over radio): Hey, Aki, just to update you guys,

so right now we're in a little bit of a tug-of-war

between thrusters firing from both the SM and the MLM.

And we're sorting through the best course of action,

uh, right now.

At this point, we have no further actions for you.

NARRATOR: For nearly 45 minutes,

the I.S.S. drifts out of control.

A combined effort of the Zvezda and Progress 78 modules

pushes back against Nauka.

It's putting huge strain on the space station's structure.

SCOVILLE: This was like riding a bucking bronco

and we've got to make it the full eight seconds,

except this time,

it was in orbit around the entire Earth.

♪ ♪

NARRATOR: It will be another 45 minutes before Russian controllers

can regain command of Nauka's thrusters.

♪ ♪

But then, all of a sudden...

♪ ♪

MAN (over radio): Aki, uh, we can report

that the MLM thrusters are no longer firing.

We are back in attitude control.

Rates are stable.

AKIHIKO HOSHIDE: Okay, copy.

NARRATOR: Nauka's thrusters fall silent.

Its fuel tanks have run dry.

The tug-of-war is over.

♪ ♪

SCOVILLE: As we brought the space station back to normal attitude,

I think we all took a, a deep sigh of relief.

NARRATOR: After rotating one-and-a-half times, around 540 degrees,

mission controllers can finally bring the station to a halt

and begin a controlled return to its correct attitude.

SCOVILLE: The team that I had working in the control center that day

was an example of performance

that to this day I will always remember.

Not because we did everything perfect,

but because of how we came together.

♪ ♪

NARRATOR: Since its launch in 1998,

the I.S.S. has been humanity's laboratory in the sky.

BUCHLI: Over the past 25 years,

we have served over 5,000 researchers

on the International Space Station,

conducted over 4,000 different experiments...

...and published right around 4,000 papers.

ALIBARUHO: The fact that we've learned so much,

not just about technology, but about ourselves,

as a result of the I.S.S.,

that's a legacy that's not to be denied

or discounted in any way.

♪ ♪

NARRATOR: For many, the value of the I.S.S.

goes far beyond the physical.

It's about perspective,

hope,

and the shared pursuit of something greater.

PARMITANO: The space station

is not just a place where we produce science,

but it's a place of emotions.

It is a place of humanity.

A place where we brought with us our own dreams.

♪ ♪

PESQUET (translated): It's absolutely phenomenal.

There is a technical feat,

but I think that the dream and the conception of the world,

a bit of multilateralism and scientific cooperation

between the countries behind it,

which for me, are even more beautiful.

CHARI: A quarter-century of peaceful cooperation,

multiple countries,

multiple organizations,

all working with the focus of trying to make humanity better,

to me, that seems like a pretty powerful and lasting legacy.

♪ ♪

NARRATOR: But with aging technology

and the advent of new, more efficient space platforms,

the station's days are numbered.

SCOVILLE: The I.S.S. was never meant

to be a permanent structure in space.

NARRATOR: The International Space Station

is scheduled to begin its final chapter in 2030.

♪ ♪

SCOVILLE: About a year and a half before the space station deorbits,

we will launch a crew that will stay there for a year.

They will be in charge

of getting the last bits of science and engineering we can

out of this facility.

♪ ♪

About six months prior to the deorbit process,

that crew will come home,

leaving the space station uncrewed

as its altitude starts to lower.

♪ ♪

NARRATOR: A deorbit vehicle will attach to the I.S.S.

and gently guide the station into a slow, deliberate descent,

where it will enter the thick layers of Earth's atmosphere

at speeds over 17,000 miles per hour.

♪ ♪

Experiencing temperatures close to 3,000 degrees Fahrenheit.

♪ ♪

SCOVILLE: We know some of it will burn up,

but large pieces of it will survive

through the atmospheric re-entry,

and that's why we want to make sure

that it's a controlled process,

so we safely hit the Pacific Ocean.

♪ ♪

NARRATOR: The I.S.S.'s fiery disintegration

will be the final act in its incredible journey.

♪ ♪

But the lessons we learn from its time in space,

the technologies developed,

and the unity it represents

will echo in future space exploration

for generations to come.

RENITA FINCKE: The I.S.S. is not just

a international laboratory that's orbiting in space.

It's much, much more than that.

♪ ♪

LAWRENCE: No matter where we come from,

no matter the differences in political systems

and the leaders that we have,

we really can work together.

We have that ability.

♪ ♪

CASSIDY: It's just really fun to think

about the future of space exploration

and to know that I was, in a small way,

part of the International Space Station's story.

♪ ♪

The International Space Station

is the crowning achievement of human ingenuity so far.

(static hissing)

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