Original subtitles

In the 1970s, we sent them to the outer

planets, thinking they might last five years.

Forty years later, two little machines called Voyager, with hearts of gold,

are still going strong.

I have to say, you know, Voyager is sort of the love of my life.

Now, more than 10 billion miles away, they're

waving a long goodbye to our solar system.

A solar system that we hardly knew before their fantastic journeys.

Facing harsh radiation, crazy temperatures, hails of particles,

whiplash speeds.

They faced mission-ending catastrophes, failed, and were

reborn, thanks to the ingenuity of their human parents.

The stunning payoff?

Close encounters with our giant outer planets and their moons.

Completely unknown worlds with massive volcanoes, some of lava, some of ice,

internal seas, and lakes of methane.

Places where life might take hold.

And now, they're creatures of deep space.

The Voyagers will be our silent ambassadors to the Milky Way galaxy.

And they're still phoning home with new answers to our cosmic questions.

These are the stories of a lonely blue marble.

Sending its intrepid little machines to places no human can yet go.

To the far ends of the solar system and beyond.

Landing a man on the moon and returning him safely to the Earth.

In 1964, as the world was riveted by the race to the moon, a graduate student named

Gary Fladro noticed something that would ultimately take us far beyond the moon.

The planets of the outer solar system were spinning towards a rare alignment that

would make it possible, in theory, to hurl something off of Earth and have it

slingshot past all the outer planets of the solar system.

Best of all, the craft could be sent close enough to each planet to get whipped by

gravity to higher and higher speeds using almost no fuel.

It was called the Grand Tour.

And it wouldn't happen again for quite a while.

The Grand Tour was an opportunity that happens once every 176 years when Jupiter,

Saturn, Uranus and Neptune were all lined up so a

spacecraft could fly by all four in its journey.

It was a chance NASA couldn't pass up.

The Grand Tour itself was a very ambitious journey

with four spacecraft flying by all the outer planets.

But it was much too expensive for everything

that was trying to be done by NASA at the time.

And they scaled it back to just a four-year mission to Jupiter and Saturn.

Unofficially, they never gave up on the idea

of a full Grand Tour to Uranus and Neptune.

They just kept their heads down and tried to engineer

the living daylights out of the Voyagers, just in case.

And so they would kind of fudge things here and there or buy different parts that

might cost a little bit more but would make the mission last longer.

So in some sense they went against what their management would say, tell them they

need to do, but they never told their management.

They just went and did that and made that selection

so the Voyager could fly as long as possible.

Voyagers 1 and 2 are identical spacecraft made up of 65,000 separate parts.

Each is equipped with instruments to conduct 10 different experiments including

television cameras, infrared and UV

sensors, magnetometers and particle sensors.

Each could radio information directly to Earth or

record data for sending later on an 8-track tape.

How 70s is that?

Each Voyager also carried a radical new computer

that was self-testing and self-repairing.

Each craft weighed about the same as a two-seater smart car, one that would have

to be accelerated to 25,000 miles per hour to escape the Earth's gravity.

So, weeks apart in late summer 1977, Titan Centaur rockets prepared to tear

away from Cape Canaveral with their little charges aboard.

Voyager 2 left first.

But Voyager 1 was sent on a more direct route, meaning

it would reach the outer planets weeks ahead of its twin.

Let us learn together and laugh together.

Jimmy Carter was president.

Star Wars had taken the world by storm.

And two dropouts in a garage had invented a personal computer named Apple.

The Voyagers had mothers who would be in

charge of their day-to-day care and feeding.

Actually, the minutely detailed lines of code telling them exactly what to do.

Among them, Linda Spilker.

I felt very maternal toward Voyager.

And I know if anything would go wrong with Voyager, we'd all worry until we got that

signal back and the sign that everything is okay and we're ready to go on.

And later, Susie Dodd.

It was super exciting.

This is my first job out of college.

And during the time of the encounters, all the scientists came.

Carl Sagan was here.

And they would all come to JPL and look at the data as it was coming down.

The beginnings were not auspicious.

Voyager 2 had computer glitches on the launch pad.

It appeared to get vertigo during lift-off and almost didn't make it out of orbit.

The first stage of the launch vehicle underperformed.

And the upper stage was just barely able to do anything.

It had to fix it on its own by literally burning itself out of fuel.

There's nothing you can do when that happens.

Then, just two hours into the flight, Voyager 2

seemed determined not to speak to her human handlers.

Her primary radio receiver failed.

Very shortly after launch, we lost one of the command receivers.

So that's the way you can send a command to let the spacecraft get new instructions.

The other remaining command receiver was tone-deaf.

It could not tune to the frequency that we were sending.

And so that meant we had to learn on the ground how to send the right frequency.

So when it got to the spacecraft, it was the one the spacecraft could listen to.

And we learned how to do that.

We flew the whole mission, our flying mission today, always knowing where to

find that frequency that is needed for Voyager to actually hear it.

The Voyager's first encounters with Jupiter would

take place during the spring and summer of 1979.

Jupiter is a very dangerous place.

The massive planet emits incredibly harsh radiation.

No human would have survived aboard Voyager.

And during the approach, Jupiter started attacking the

probes, invisibly and potentially catastrophically.

The radiation was pinging the clock that controlled the camera and putting it out

of sync with the clock that controlled the exposure.

The engineers at JPL managed to come up with a workaround.

And everyone held their breaths as Jupiter got larger and larger in the images.

The Great Red Spot, discovered 300 years earlier, turned out to be not one storm

but hundreds swirling within and around a giant,

multicolored vortex more than three Earths across.

As we started 30 days out from Jupiter, began to make a movie of the very complex

storm systems in Jupiter's atmosphere, the

Great Red Spot is just the largest hurricane.

There are literally dozens of these storms in this giant planet.

And that was our first taste of the discovery that was waiting for us.

As Voyager 1 swung through the system at 35,000 miles

per hour, JPL went wild at the quality of the images.

But if Jupiter had amazed them, the real shock

would come from the giant planet's moons.

Io is Jupiter's innermost moon.

A close look at the images revealed the driest object in the solar system.

But nobody was prepared for what showed up next.

And it took a graduate student who was looking in

the details of the images and saw this big arc.

And she said, hey, come and look at this.

And people said, oh my God, volcano.

It had eight active volcanoes when Voyager flew by.

It has ten times more volcanic activity than

the Earth, even though it's just a small moon.

And it had lakes of hot lava on its surface.

Let's not forget that before the Voyager encounter with Jupiter and its moons,

the only example of volcanoes we knew about was Earth.

How was it possible that this moon, so far from the sun, in the deep cold,

was erupting hot lava?

Scientists had just started theorizing that the incredible push and pull of

Jupiter's gravity would squish and stretch the moons, heating them up.

And boy, did they.

It turns out these moons are in orbit around the giant Jupiter, and that creates

a tide in the moon, just like the moon creates a tide in our ocean.

Well, Jupiter creates a tide in the moon and deforms it.

And that deformation as it works around heats the moon.

In the case of Io, it causes volcanic activity.

The team didn't think they would run across other

discoveries that were that outrageous in the Jovian system.

But Voyager's images at Jupiter's second-closest big moon, Europa,

were a shock as well.

It was smooth as a bowling ball, but scratched.

It looked like the surface consisted of millions of little plates, sort of what

you would see when an ice pack is breaking up during the spring.

Could they possibly be skating over an ocean?

Europa essentially has a shell of ice that could be as deep as 20 kilometers or more.

And underneath that, however, there is liquid water.

And the ice itself is not absolutely impermeable because we see cracks.

We see stuff that has come from underneath at various times.

The implications were stunning.

Life on Earth probably arose in a primitive ocean.

Did Europa have one?

Later mission Galileo showed that it did indeed.

The largest ocean in the solar system.

You have all the ingredients that we now know constitute the elements of life.

You have water.

You've got apparently organic material.

And you've got the source of energy, which is the heat generated by the

gravitational pull from Europa and Jupiter and Io that

continuously charms this underground under-ice ocean.

And the other moons followed suit.

Europa, Ganymede, and possibly even Callisto appear to have vast oceans of

liquid water under relatively thin shells of ice.

Where scientists had expected dark, dead cratered moons like our own,

they found mysteriously dynamic worlds.

And those tiny moons that were basically points of light and

telescopes from the ground suddenly started to be revealed.

First Callisto, ancient and cratered, then Ganymede with its grooves and

tectonic activity, bright white icy Europa, and then active Io.

So these points of light became worlds in their own right.

There was little time to celebrate.

In just 16 months, the Voyagers were hurtled by the crown jewel of our solar

system, Saturn, which turned out to be more beautiful

than anyone could have imagined and nearly as dangerous.

It was a time of Pac-Man, Reagan, and the birth of the 24-hour news cycle.

In November 1980, Voyager 1 swung through the Saturnian system, around behind the

rings, and made a beeline for its largest moon, Titan.

Earth-based telescopes had shown that Titan had an

atmosphere, making it the must-see destination for scientists.

Voyager 1 could not see through the haze to the surface, but it could register that

the atmosphere was largely nitrogen, just like Earth's.

There was methane as well.

Methane, we'd later discover, was so cold that it probably snowed on Titan's surface.

Enceladus, Saturn's sixth largest moon, was brilliant

white, the most reflective body in the solar system.

It was another candidate for having a liquid ocean beneath its icy surface.

And later, the Hubble telescope would catch it in the act of actually erupting water.

Voyager also found that Saturn didn't have three rings.

It had thousands.

Some with spokes.

Some that twisted, and braided, in ways that stumped the scientists.

The shimmering rings were made up of three rings.

Full of tiny grains of water ice.

And were unbelievably thin.

For comparison, if Saturn were shrunk down to the size of a basketball, then the

thickness of the rings would be about 1,250th the width of a human hair.

We didn't know what the rings would look like.

We thought we'd see bland sheets of material separated by gaps.

But instead we found incredible, wonderful detailed structure.

And I remember in those days you didn't have a computer screen where you could

call up a picture of the rings and instead you had to

get the data and plot it out in this long roll of paper.

And I remember taking those rolls and unrolling it in the hall and just walking

slowly, looking down thinking, I'm walking through the rings of Saturn.

And what a wonderful feeling.

Having finished its official mission, Voyager 1 was

slung up and out of the plane of the solar system.

This cleared the way for what everyone had in mind.

That Voyager 2 could complete the grand tour and visit more planets after Saturn.

But only by sending it careening dangerously close to

Saturn's surface to make a hard left toward Uranus.

Then Voyager 2 slipped into the shadow of the planet.

And the images suddenly went dark.

Had they come this far?

With Uranus and Neptune in their sights?

Only to have lost their robotic eyes.

After the Saturn flyby, the Voyager 2 scan platform got stuck.

And it just wouldn't move.

And so we just saw outbound these pictures of Saturn.

We wondered, could we fix it in time to get to Uranus?

Voyager 2 emerged from behind the planet.

Directly on course.

And accelerating like mad.

Thanks to the gravity boost from the close flyby.

But it looked like the camera platform had balked at the sheer

speed of the commands it had to execute to take stable images.

The engineers studied the phenomenon and figured out a way of how to pulse it

enough to make the platform move at a fairly constant rate.

And just the hours of people studying and thinking and finding ways to fix it.

And then we were all cheering.

Yes, we found a way to keep the Voyager mission going.

But how would they take pictures at Uranus when

they'd be moving 20,000 miles per hour faster?

And the sunlight would be four times fainter.

It would require the most ingenuity yet.

Susie Dodd joined the Voyager team in time for the approach to Uranus.

So in order to make what you want to look at bright

enough, you really have to stare at it for a while.

But your spacecraft is tracking so fast, it'd be like trying

to take a picture of a sign as your car is whizzing by it.

You know, you have to track that.

And we designed attitude control software so that we could track the target we were

looking at in order for the exposure not to be smeared or to be too dark an image.

Five years after the Saturn flyby, they were ready for Uranus.

Or so they hoped.

I'll do my utmost to be deserving of your trust.

Uranus rolls around the Sun rather than spins.

Voyager 2 would fly through the bullseye of its system like an arrow at 51,000

miles per hour, passing close to the innermost Moon.

Tiny Miranda.

As crazy as the Saturn flyby had been, it had taken three days.

This time, they would have just ten hours.

Miranda turned out to be one of the most geologically bizarre bodies in the solar

system, with crazy V-shaped grooves and 50,000-foot-tall ice cliffs.

To this day, we don't fully understand this strange patchwork quilt of a mini-moon.

I kind of like Miranda, which is one of Uranus's moons.

It's a small moon, and it has this big checkmark in the middle of it.

It's like, okay, you know, I'm okay.

I'm here, Mom.

I'm here, planet Uranus.

The Uranus flyby and images completely surpassed what JPL had hoped for.

Voyager 2 was now five years beyond her original mission, all those years ago.

The engineers' secret plans to keep the probe

going through the Grand Tour were paying off.

And now, Voyager 2 was headed towards its last planet, Neptune.

It arrived just 62 miles off its target, just above Neptune, after traveling 4.

4 billion miles.

Something lead designer Charlie Culhays estimated was roughly equivalent to a

golfer sinking a putt from Washington, D.C.

to Phoenix, Arizona.

The movies of the approach are eerie.

There was a large, dark, oval-shaped feature in Neptune's southern hemisphere,

similar in shape to Jupiter's great red spot.

And when small white clouds came into view, it confirmed another giant

Earth-sized storm system, which shouldn't be there.

Neptune has about 900 times less light than here on Earth,

yet it has the fastest winds that we saw in the solar system.

Well, I think nobody knew that there was this giant storm at Neptune.

Now, that storm doesn't exist anymore.

From 1990 to 2016, where we are today, that storm has

dissipated and is no longer seen in the atmosphere of Neptune.

That's kind of neat.

After swinging just 3,000 miles, above the cloud tops of Neptune,

Voyager 2's trajectory would take it past one final, glorious, unknown destination.

The moon, Triton.

And yet again, the scientists would be greeted by an inexplicable object.

An explosive one.

Triton was a very big surprise.

It's very cold, only 40 degrees above absolute zero.

The nitrogen is frozen into an icy polar cap that's so cold.

And yet, we found several active geysers erupting

from that surface at 40 degrees above absolute zero.

Another big surprise.

With that last flyby, Voyager 2 was hurled slightly south of the plane of the solar

system, on its own search for interstellar space.

For the team at JPL, it was a bittersweet time.

We were all excited.

The press was here.

It was in the news all the time.

It was very thrilling.

And then the press kind of left, and the news died down.

And you still had the spacecraft, which was kind of sad.

It was now off, going out into the cold, dark space on its own, alone.

It's estimated that a total of 11,000 work years were devoted to the Voyager Grand

Tour, equivalent to a third of the labor force

needed to complete the Great Pyramid at Giza.

The results were nothing short of revolutionary.

The Voyagers really changed our visions of the outer solar system

by showing it to be a far more dynamic place than expected.

But the Voyagers weren't done yet.

Not by a long shot.

Now, both probes were headed out of the plane of

the solar system, still functioning perfectly.

There was a chance that if they could hold on for another five or ten years,

they could reach interstellar space, beyond the influence of our sun.

Well, Voyager flew very quietly.

And I would say very much sort of in the background while we were landing

spacecraft on Mars and Cassini was up taking great images of Saturn.

For another dozen years, the Voyagers, now 30 years past their sell-by dates,

logged the diminishing force of the sun's gravity, its magnetism, and the solar wind.

They found all kinds of bizarre formations, including a magnetic bubbling

at the outer limits that protects us from deadly cosmic rays, blasted out of the

hearts of supernovas throughout the galaxy.

Today is a historic moment for NASA, the Voyager team, and in fact, humankind.

Well, this is the spacecraft, the first to interstellar space.

We made it!

It was tremendously exciting to think that a spacecraft I had worked on, I had been a

part of, was actually now leaving our solar system and

going out for the first time into interstellar space.

Any of the particles that are hitting Voyager now are coming from other stars.

They're not coming from our sun.

So we're actually measuring for Voyager 1 particles

and dusts and winds that are coming from other stars.

It's the very first time that humanity sort of moved out of the cocoon of the

solar atmosphere to venture beyond the solar

system and into the source of the galaxy.

That only happens once, and it happened in our lifetime.

The Voyagers are now flying blind, feeling their way through the universe.

Their cameras shut down to preserve the tiny bit

of power left in their little nuclear power plants.

With a little luck and pluck, these will keep generating energy for another decade.

So we think we can operate all the instruments until 2020.

We should have enough power to do that.

But after that, we'll be turning off one instrument at a time.

And probably by 2025, we won't be able to have any more science instruments on.

But my personal goal is to operate the spacecraft for 50 years.

So I want to see it operating at least until 2027.

Remarkably, Voyager's controllers still talk to the probes every day, despite the

fact that the signal from so far away is

down to about a billion billionth of a watt.

But it can't last forever.

Yeah, one day, it's going to be a very sad day, but one day we will expect to hear

from the spacecraft, and we won't hear from it anymore.

And we will send a lot of commands from the ground to try and recover it,

and we'll try different things, but eventually it won't have enough power

for the transmitter, and so it'll just stop transmitting data.

And then it will just be our silent ambassador

traveling around the center of the Milky Way galaxy.

But it's still on a big adventure.

It's just that I won't get to know what that adventure is.

It will be another 40,000 years before Voyager 1

drifts within shouting distance of another star.

Just in case there's intelligent life out there ready to

snag it, they'll discover Voyager's message to the universe.

A 12-inch gold-plated record containing greetings in dozens of languages.

Hello from the children of planet Earth.

Samples of music and sounds of nature.

Hints of an Earth and a people that may long have perished.

That record has the sights and sounds of the

Earth, pictures, songs, people saying hello.

And so maybe someday some other civilization will find Voyager.

And there's even directions on the cover of

the record of how to find us, where we are.

They will be orbiting every 240 million years

around the center of the Milky Way galaxy.

Year after year after year for billions of years, carrying this plaque and record

saying we sent this to the Milky Way galaxy.

This kind of adventure doesn't happen often in human affairs, and I think

Voyager is the the Columbus, if you like, of the space era of discovery.

Voyager is still doing path-breaking science

as we speak, and it continues to do so.

You can't do it any better than that.