NOVA

NARRATOR

Apollo 8-- a last-minute change sets a mission on a dangerous new course.

JERRY BOSTICK

I said, "What?! That's the craziest idea I ever heard." (rocket engines ignite) A lot of risk.

NARRATOR

Untried technologies put to the test. (explosion)

MICHAEL COLLINS

Any one of them can be a disaster if it doesn't go perfectly well. (explosion)

NARRATOR

It's the height of the Cold War; two superpowers race to the moon. They were beating us at every turn. I want to be part of winning. A president's deadline looms.

JOHN F. KENNEDY

Landing a man on the moon before this decade is out... There's just enormous pressure.

NARRATOR

Then, tragedy strikes.

MAN (on radio)

Hey! We've got a fire in the cockpit!

DAVID MINDELL

"How are we ever going to get there?"

NARRATOR

A secret decision is made.

FRANK BORMAN

He said, "Close the door," so I realized that something was big. (rockets ignite)

NARRATOR

A half-century later, the legacy of this audacious journey affects us all. (hissing) The mission that got us to the moon. "Apollo's Daring Mission," right now, on "NOVA." (static buzzing)

NEIL ARMSTRONG (on radio)

I'm at the foot of the ladder.

NARRATOR

It is perhaps the greatest technological feat in history.

ARMSTRONG

Okay, I'm going to step off the LEM now.

NARRATOR

Humans arriving at another world.

ARMSTRONG

That's one small step for man; one giant leap for mankind. (cheers and applause)

NARRATOR

Yet before the arriving could happen, first there was the leaving. (indistinct talking on radio)

MAN

...pressurized.

NARRATOR

It's December 1968. A space mission unlike any other begins-- Apollo 8.

POPPY NORTHCUTT

It was the most dangerous mission of all.

BOSTICK

It was the boldest move that NASA ever made.

NARRATOR

Three men-- Frank Borman, Jim Lovell, and Bill Anders-- are departing on a journey no one has ever made before.

COLLINS

For the first time in human history, humans left earth.

NARRATOR

All previous missions have stayed in earth orbit. But these three veteran fighter pilots-- Lovell from the Navy, Borman and Anders from the Air Force-- will take their spacecraft to another world. Apollo 8 will orbit the moon ten times; it will not land. But this mission will make the landing possible

by testing key technologies needed to reach the moon

a giant rocket, a redesigned spacecraft, a revolutionary new computer. The rocket has never carried humans before. The spacecraft and computer have flown only once, on Apollo 7-- a mere 180 miles off earth's surface.

NASA WORKER

One, zero. (rocket engines ignite) (indistinct talking on radio)

NARRATOR

Apollo 8 will take these untried technologies on a half-million-mile round trip in the ultimate test.

MAN (on radio)

We have cleared the tower.

MAN 2 (on radio)

Roger.

BILL ANDERS

We probably had one chance in three of making a successful flight, had one chance in three of not being able to do our mission but at least making it home alive, and one chance in three of not making it back.

NASA WORKER (on radio)

Apollo 8, Houston, you are a go for staging, over.

NARRATOR

It is a giant risk. (film projector humming) But originally Apollo 8 was supposed to be a baby step-- just another test flight around the earth.

MINDELL

It took years of test flights. And you really have to think, of course, of the Apollo flights as a system.

ANDERS

It was the typical NASA inch-by-inch, one-step-at-a-time approach.

NARRATOR

But in the summer of 1968, years of careful planning and preparation are suddenly upended by an alarming discovery.

JAMES LOVELL

We were training in California, the three of us-- Bill, myself, and Frank-- when suddenly Frank got called back to Houston.

BORMAN

Deke Slayton said, "Frank, "I want you back here in Houston right away. I have to discuss something with you."

NARRATOR

Deke Slayton is in charge of the astronauts. And so I said, "Well, Deke, let's discuss it now, I'm busy. I can do it over the phone." And he reminded me who was boss. Things weren't gentle and politically correct in those days. We weren't candy asses, okay? (jet roaring) And so I went back to Houston. And he said "Close the door," so I realized that something was big. A CIA spy satellite has photographed an enormous Soviet rocket on a launchpad. It can mean only one thing.

BORMAN

The CIA had information that the Soviets were planning on sending a man around the moon in the year of 1968.

NARRATOR

A Soviet cosmonaut reaching the moon would be a stunning defeat for America. (explosion) For years, the U.S. and Soviet Union-- both armed with nuclear weapons-- have been locked in a deadly cold war.

DEBORAH DOUGLAS

There was a sense that communism was a profound threat to democracy and to the United States.

NARRATOR

Starting in 1957 with Sputnik,

the Soviets open a new front

space.

DOUGLAS

Yuri Gagarin, Valentina Tereshkova, blow after blow after blow. They were beating us at every turn.

NARRATOR

In April 1961, a new president, John Kennedy, writes a memo about space that will have profound consequences.

HUGH BLAIR SMITH

He said, "Guys, find me something we can beat the Russians at." Now it is time to take longer strides. I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth. (applause)

Kennedy has set a firm deadline

the end of the 1960s.

BOSTICK

It was a simple, one-sentence statement-- the goal and the schedule. Clear, succinct-- no fuzz on that goal.

BORMAN

I never joined NASA to explore space. Yeah, basically I was a military person, and it was clear to me that we were in a serious confrontation with the Soviets. I want to be part of winning.

NARRATOR

Military test pilots-- now "astronauts"-- begin flying in 1961. By 1967, Americans have mastered the basics of space flight and all the techniques needed to reach the moon. Apollo, America's moon program, is about to take its first step. Apollo 1 will be a test of the new spacecraft, the command module, around the earth. The crew is Gus Grissom, America's second man in space; Ed White, who took America's first spacewalk; and Roger Chaffee, a Navy pilot who flew airborne photography missions during the Cuban missile crisis. (elevator gears whirring) Three weeks before launch, a dress rehearsal on the ground-- a practice countdown. It's January 27, 1967, a Friday. Things are not going well.

ENGINEER

Ah, who's transmitting?

GRISSOM

This is the command pilot, do you read me?

JOHN AARON

It was the end of a very frustrating day.

ENGINEER

You're pretty garbled here, Gus. They were having communication problems with the crew.

GRISSOM

How we gonna get to the moon if we can't talk between three buildings?

WHITE

They can't hear a thing you're saying.

GRISSOM

Jesus Christ. When all of a sudden, you know, I thought I heard "fire!" (on

radio)

Hey! We've got a fire in the cockpit!

NARRATOR

The fire quickly becomes an inferno. And, you know, the rest is history. With no chance of escape, poisoned by toxic fumes, three astronauts perish.

BOSTICK

It was a pretty sad scene. Most of the guys were sitting on their consoles with tears running down their cheeks, you know, just couldn't believe what had happened.

MINDELL

Everybody knew what they were doing was dangerous, but they didn't really think of it as being dangerous on the ground. And it was a huge shock that an accident like this would happen in kind of an ordinary training scenario without being in space.

NARRATOR

Over the next few months, the charred spacecraft is painstakingly disassembled, each piece tagged, studied, and photographed... (camera shutter clicking) 5,000 images in all. Sifting through these artifacts, the Apollo Review Board pieces together what went wrong.

BORMAN

We came out with a scathing report on the problems not only of the test in which the fire occurred, but also in the development of the spacecraft.

RAMON ALONSO

There was no ass-covering. There was a lot of soul searching as to what had happened and all of the things that went with it.

NARRATOR

Electrical wiring shows shoddy workmanship. Investigators believe the fire began with a spark from a wire that had rubbed bare. That spark quickly became an inferno, because the command module was full of flammable material.

AARON

Everywhere you turned there was stuff that would be subject to a flash fire if you got the right ignition source.

NARRATOR

On top of that, the atmosphere inside could not have been more dangerous.

LOVELL

Pure oxygen at 16 pounds per square inch. Something which we all should have known, that anything will burn in pure oxygen at 16 pounds per square inch.

NARRATOR

And, finally, the hatch. It's cumbersome to unlock, and it opens inward. Expanding gases from the searing heat meant tons of force held the hatch closed. The fire is a shock to the system that reverberates throughout Apollo. It caused NASA to stop and reflect on everything it was doing and redo it.

ALONSO

But for the fire, there wouldn't have been the reexamination of all kinds of things.

BOSTICK

We redoubled our efforts. We said, "You know, those guys were our friends. "And we're going to get to the moon, on time, in their honor."

NARRATOR

But getting to the moon on time won't be easy. They've got to completely redesign the command module, perfect a lunar lander, figure out how to navigate to the moon and back, and build a rocket larger and more powerful than any that has ever flown. It will be known as the Saturn V. The key innovation that enabled all of Apollo was the Saturn V rocket. Without that, you couldn't even say we were going to the moon. It will weigh over six million pounds, stand as tall as a 36-story building, and be able to lift 130 tons. America's moon rocket is the brainchild of German engineer Wernher von Braun. During World War II, von Braun and his team develop the V-2 rocket. Built with slave labor, V-2 rockets kill thousands in London, Antwerp, and elsewhere. After the war, von Braun is brought to the U.S. to build rockets for America. to build rockets for America. Sonny Morea is project manager the bin June 1962,uilt-- when NASA test fires its first F-1. (flame roaring) When we tried to fire it for the first time... (explosion) it just blew apart. (explosion) As F-1 engines keep blowing up,

engineers finally identify the problem

combustion instability-- uneven burning. If you visualize a candle burning in a room, it flickers from side to side. Well, that's a form of instability. What happens there is that it sees more oxygen on one side, and so it produces more heat, and it pushes the flame over to the side. Well, that flips back and forth maybe five or six times in a second. That same phenomenon happens in an F-1 engine, but they don't flip at five times in a second. (explosion) They flip 2,000 times in a second.

NARRATOR

Like a massive, out-of-control candle, the fire inside the F-1 surges back and forth until it destroys the engine. They have no idea how to fix it. The F-1 engine is simply too far ahead of the state of the art, and too enormous, to apply any known theory. The solution had to come by trial and error. You know, you find a way or make one, that's the way it was back then. It was absolutely the seat of our pants. If they can't fix the F-1, Apollo is finished.

MOREA

If we couldn't solve the combustion instability problem, we would not have gone to the moon. It was too risky, we would have killed a bunch of astronauts trying to make that work. (rocket igniting)

NARRATOR

So the engineers turn to von Braun's original V-2. Why didn't combustion instability destroy that engine? In the V-2, liquid fuel and liquid oxygen were injected through a number of separate nozzles. In the F-1, fuel and oxygen are injected through a single flat injector plate, like a showerhead. The engineers wonder, did the multiple nozzles of the V-2 somehow divide the burning into separate zones? If so, perhaps adding metal ridges-- baffles-- to the injector plate would create a similar effect in the F-1.

MOREA

If we broke that into segments with baffles, hopefully they wouldn't talk to each other, similar to what the V-2 had.

NARRATOR

After many experiments with baffles... (explosion)...eventually they get the engine to run smoothly.

MOREA

Lo and behold, we found out that the baffles were able to attenuate the oscillations.

NARRATOR

But how can they be certain the F-1 will work every time? They try deliberately causing the problem by setting off a small explosion inside the engine while it's running. Can baffles stop instability after it starts? We drove it unstable with a bomb. We inserted a bomb right into the center of the injector and blew it just at the time we ignited. (explosion) With the engine running, the small bomb explodes; the burning becomes unstable. But in a fraction of a second, the baffles quickly stop, or dampen, the instability. That would drive the engine unstable, and then it would dampen out right away, where before it wouldn't. And every single time those baffles dampened out the oscillations. (explosion) In November 1967-- two years and one month before Kennedy's deadline-- the Saturn V rocket has its first unmanned test flight.

COLLINS

We got as close to it as we could, something like two-and-a-half miles away.

NARRATOR

Among the spectators is astronaut Michael Collins.

COLLINS

When the engines ignited, it didn't seem like a big deal. And then the shockwave came. (loud rumbling, forceful wind whipping) And the shockwave got you in the viscera, got you in the brain, got you shaking. If you ever want to know what power meant, that was it.

NARRATOR

The five F-1 engines and everything else work perfectly. But leaving Earth on a rocket is just the start. To reach the moon, they'll have to cross a quarter-million miles of empty space and hit a target that's only about 2,000 miles across. In space, everything is moving around. I mean, the earth is moving around the sun, the moon is rotating around the earth. There's all this movement, so how do you hit the target? To hit the moon, NASA turns to Charles Stark Draper, better known as "Doc"-- engineer, aviation pioneer, MIT professor.

COLLINS

Stark Draper was the leader of the Instrumentation Lab at MIT, Massachusetts Institute of Technology. Very technical guy who has put together this intricate bunch of equipment.

NARRATOR

Starting in the 1930s, Draper develops a new way for pilots to always know where they are-- even at night, in fog, or thick clouds.

MAN

On inertial and transfer power. (engine rumbling)

NARRATOR

Inertial navigation. It allows a pilot to navigate from point A to point B without knowing any information other than where he started. But on Earth, points A and B are stationary with respect to each other. In space, they're on two different celestial bodies, Earth and moon, and both are constantly moving. To reach the moon, Apollo will have to speed up, slow down, change direction, multiple times. So Apollo needs the most accurate navigation system possible. It will have several parts. The first is the inertial measurement unit. Inside, gyroscopes measure changes in direction; accelerometers, changes in speed. Starting at the launch in Cape Canaveral, Florida, by measuring every change in speed and direction, it keeps track of the spacecraft's location. But it's not perfect. (dial clicking) Gyroscopes and accelerometers are mechanical devices. Each day, a little bit of error creeps in.

SMITH

In long missions like Apollo 8, the inertial measurement unit isn't quite constant. It does drift a little bit.

NARRATOR

So the second part of the system is a check on the inertial unit,

a way to correct its daily error

the Apollo space sextant.

SMITH

After about a day, you want to have somebody go to the sextant in the wall of the spacecraft, sight on a couple of stars, and then basically correct the orientation.

NARRATOR

With the space sextant, the navigator can determine the spacecraft's location by measuring the angle between a reference star and the edge of the earth. Knowing that angle, he can use trigonometry to calculate his position in space. Together, the inertial measurement unit and space sextant-- combined with ground tracking-- will tell astronauts and Mission Control where they are. But knowing where they are is only half the battle. They'll have to maneuver into and out of lunar orbit. And MIT thinks that's too hard for a human pilot-- it can all be done by a computer.

MINDELL

It needs just two buttons. One button will say, "Go to moon," and one button will say, "Take me home."

NARRATOR

The astronauts respectfully disagree.

MINDELL

"No, no, no, no, no! "I'm up there, "it's my rear end that's on the line, I need to be in control of the spacecraft."

ALONSO

The very first thing one of the astronauts said to me, "As soon as we get up there, we're shutting the sucker off!"

NARRATOR

But maneuvering the Apollo spacecraft involves firing 16 different thrusters plus the main engine. So you better have 17 fingers and be awfully, awfully agile. After a long battle, NASA decides the astronauts will control a computer, and it will maneuver the spacecraft, a system called "digital fly-by-wire."

MINDELL

Fly-by-wire is where the pilot is really controlling a model inside the computer, and then the computer does whatever it needs to do to make the spacecraft fly like that model.

NARRATOR

The inertial measurement unit, the space sextant, and ground tracking pinpoint where the spacecraft is. The computer knows where they want to go. So it figures out how to burn the thrusters, plus the main engine, to get there. Human life will be entrusted to decisions made by a machine.

MARGARET HAMILTON

A person's life was at stake, in this case the astronaut, so it had to work.

NARRATOR

Margaret Hamilton develops software that will control the Apollo computer.

DOUGLAS

Computers, they don't do anything until they have some instructions. That is the software side of things.

NARRATOR

Hamilton and her team will have to create software that enables this computer to prioritize different tasks, without freezing.

HAMILTON

We, the developers, had to assign unique priorities to every job. And if there's an emergency, we wanted to interrupt everybody and say, "Look, I'm coming in here "for something that's an emergency, everybody else gets downgraded."

NARRATOR

And there's still one more requirement

for this new computer

it must be tiny.

ALONSO

The way that the size of the computer got determined was not by what it had to do. Out of the blue, they said "Okay, here's a cubic foot, fill it with computer." "Computer" in the 1950s meant something that was basically the size of a building.

NARRATOR

It seems completely impossible. But lead designer Eldon Hall thinks a new breakthrough in electronics might just be what they need.

SMITH

Eldon Hall said, "The only way we're going to get small enough, low-power enough, and reliable enough is to switch to integrated circuits."

NARRATOR

Integrated circuits shrink hundreds of transistors and other components down into one tiny chip. But can such a computer be built? Not only small, but able to prioritize tasks, easy to use, and 100% reliable? As the summer of 1968 arrives, barely 18 months remain until the Kennedy deadline. Then, the CIA brings the shocking news that the Soviets are poised to send a man around the moon. Rather than lose to the Soviets, Apollo spacecraft manager George Low proposes a radical change of mission. Instead of orbiting the earth-- the original plan-- send Apollo 8 a half-million miles to the moon and back. I said, "What? That's the craziest idea I ever heard." Chris Kraft, director of Mission Control, orders engineer Jerry Bostick to study the possibility.

BOSTICK

This is a Friday, Friday afternoon, as a matter of fact. He said, "You've got until Monday morning to figure out if we can do it or not."

NARRATOR

The command module-- redesigned after the fire-- still hasn't flown; the guidance computer hasn't been tested in space. And the Saturn V, which did so well on its first unmanned test flight, had major problems on its second. Still, the engineers conclude this new mission might just work.

BOSTICK

We recognized that, "Yes, this is not going to be a piece of cake, but we can pull it off."

NARRATOR

The improved command module-- now with better wiring, a new easy-to-open hatch, and no more pure oxygen on the ground-- will be tested around the earth first, on Apollo 7. If that works, Apollo 8 will go to the moon.

BORMAN

And all of a sudden Jim and Bill and I began frantically training for the lunar mission.

ANDERS

NASA usually went step by step. In this case they jumped three or four steps.

LOVELL

Well, I thought that was a grand idea. This was exploration; this was a mini Lewis and Clark expedition. (indistinct talking on radio, rockets fire)

NARRATOR

In October 1968, the redesigned command module is tested around the earth and performs perfectly. Apollo 8 will proceed. But first, a final review, where engineers report to management and astronauts.

MOREA

"Can you give this a clean bill of health, "that we have a safe mission ahead of us, because of your hardware?" Well, we had gone through all this combustion instability stuff, with many unknowns... (explosion)...and I couldn't say, you know? Frank Borman put his arm around me, and he said "Sonny," he says, "we know you guys have done everything humanly possible "to make this a safe flight. "We're ready to fly. Don't worry about it." (chuckles)

NARRATOR

Now, Apollo 8 will go. It's December 21, 1968.

LOVELL

The morning of the launch, I thought to myself, "We're going to the moon. This is going to go to the moon."

NARRATOR

They've prepared as much as possible. Still, this launch is an act of faith. Whether it turns out to be a desperate gamble that should never have been made or a stroke of genius, Apollo 8 is a leap into the unknown.

ANDERS

First on the Saturn V. First to leave the earth, first to go into lunar orbit. A lot of risk.

AARON

Was I nervous? Yes, I was nervous! That's a big step, that's a big step.

MAN

Ten, nine...

NARRATOR

Eight seconds to go.

MAN

We have ignition sequence start.

NARRATOR

Fuel starts pumping, 15 tons each second. (fuel igniting) The F-1 engines come alive. (engines roaring) (indistinct talking on radio)

MAN

...51 a.m. Eastern Standard Time.

ANDERS

It was so loud, we couldn't hear ourselves think; couldn't even see the instrument panel, it was vibrating so much. It was one hell of a rocket.

BORMAN

You have seven and a half million pounds of thrust pushing you; all of a sudden it stops, and you're flung forward in your seat belts and then back as the second stage took over.

NARRATOR

11-and-a-half minutes after leaving the ground, Apollo 8 is moving 17,000 miles an hour, circling the earth. Then, an unprecedented and momentous event. The third stage engine will re-light and send Apollo 8 out of Earth orbit toward the moon. It's a maneuver NASA calls, "TLI"-- trans-lunar injection.

COLLINS

"Trans-lunar injection"? It sounds like some sort of a medical device.

NARRATOR

Astronaut Michael Collins is CapCom the one person in Mission Control who speaks directly to the astronauts.

COLLINS

I mean, I love NASA, but they have an ability to transform, sometime, the ethereal into the mundane.

NARRATOR

In this moment, Michael Collins has the honor of announcing a turning point in human history. I said to them, "Apollo 8, you're go for TLI."

COLLINS

Apollo 8, you are go for TLI, over. And Borman said, "Roger, Houston."

BORMAN

Roger, understand, we're go for TLI." That was it. I just really wish I had that moment to live over again, because I would have said to them, "Apollo 8, you can now slip the surly bonds of Earth "and dance the sky, Apollo 8! Dance the sky, you go!" is what I would have said to them, instead of, "You're cleared for TLI."

NARRATOR

The words may be mundane, but the meaning is profound.

MINDELL

It was the first time that any human beings entered the gravitational field of another planetary body besides the one that we evolved on.

NARRATOR

Two-and-a-half days pass. Even now, the astronauts still can't see their destination. Our blunt slide was towards the moon. So we never saw the moon as we actually got right up to it. But they don't need to see the moon just yet. To go into lunar orbit, they have to fire their engine and slow down, to be captured by the moon's gravity. Everything about it must be perfect. If not, they could miss the moon or crash into it. And all this done by the computer.

SMITH

The computer has to figure how to turn the spacecraft so the rocket is pointing in the right direction. It then has to figure exactly when it has to be lit.

MINDELL

It has to be precisely calculated, it all needs to be timed within tenths of a second.

NARRATOR

But the computer only does this when the astronaut tells it to. So, in 1968-- with no mouse, touch screen, or keyboard-- how will an astronaut talk to the computer? MIT's answer is the display keyboard, or DSKY.

MINDELL

It has a numeric keypad, and a very simple, what you would think of now as an LED display.

NARRATOR

The real genius of the DSKY is the way it uses language.

REPORTER

To see the Apollo guidance and navigation system in operation, we've talked with Mr. Ramon Alonso.

NARRATOR

Engineer Ramon Alonso was raised in Argentina. Trying to create this language, he remembers how he learned English.

ALONSO

When you go in school, somebody said, you know, the parts of speech, part of sentences, there's things called verbs, there's things called nouns. "What is a verb?" "Well, that's the action that does something." "And what is a noun?" "It's a thing." So, all right, that seemed to suit. I remember driving to work one time and saying, "Oh, yeah, that might work." "Fire Rocket," "Fire" would be 22, and "Rocket" would be 35, or something like that. And "Display Time," "Display" might be 16, and "Time" would be 45.

COLLINS

The DSKY was designed for idiots like me. I mean, we had verbs and nouns, so that it made more sense to us. Very crude it was, but it certainly did the job.

NARRATOR

Now, almost three days after launch, the Apollo guidance computer and its DSKY interface are about to execute their first life-and-death maneuver.

LOVELL

We were coming up to what is known as LOI, lunar orbit insertion.

NARRATOR

The computer must fire the engine at just the right moment, in just the right direction, for a precise number of seconds, to drop Apollo 8 into the perfect orbit.

MINDELL

If you burn too much, you could go in too a low in orbit, that could intersect the moon. Or you could fly off into an orbit that won't come back around. There's a tremendous amount of danger with getting these orbital burns right.

NARRATOR

The LOI burn happens when Apollo 8 is behind the moon. Radio signals will be blocked, all communication cut off.

AARON

The break in communications is sharp. The trajectory engineers could tell you, based on the geometry and all the velocities, exactly when that was going to happen.

BORMAN

This was a very important parameter, because it would tell you when you lost your communications if you were on trajectory or not.

NARRATOR

Everyone counts down the minutes to loss of signal-- LOS.

AARON

There was nothing to say. You're just sitting there, and it's quiet as a mouse.

MISSION CONTROL

Apollo 8, Houston. One minute to LOS. All systems go. Safe journey, guys.

APOLLO ASTRONAUT

Thanks a lot, troops. See you on the other side. At the exact second we were supposed to lose communications, we lost it. (radio static popping, ends abruptly) And I said something like, "Whew! We must be right on... right on time." I said, "Yeah, Frank, it checked," I said, "but, you know, they're our friends down there. "they're going to pull the plug on that antenna no matter how far off we are." They probably turned off the damn radio. (laughs)

NARRATOR

For the next 35 minutes, there's nothing Mission Control can do; Apollo 8 is behind the moon and unreachable.

AARON

It was almost a relief. First of all, we'd been sitting there for three or four hours with no bathroom break. So, the first thing you do is you hit the door.

NARRATOR

Up in space, a different kind of break. We saw nothing...

BORMAN

We were upside down and backwards in perfect darkness.

LOVELL

... until we rotated the spacecraft around. Suddenly we looked down, and there below us was the lunar surface. You know, we were like three schoolkids looking into a candy store window.

NARRATOR

For the first time ever, human eyes are seeing the far side of the moon. On Earth, Mission Control won't know if the burn to go into lunar orbit worked or not until radio contact resumes.

NORTHCUTT

So we're sitting there waiting for them to come out and have acquisition of signal, to see whether or not we all needed to jump into action. Because if it went badly, we really didn't have much time to do something.

NARRATOR

Poppy Northcutt is part of a support team that will have to quickly compute emergency maneuvers to bring Apollo 8 home if the burn failed.

NORTHCUTT

It was dead silent, except for hearing the CapCom calling out, "Apollo 8, this is Houston, Apollo 8, this is Houston."

MISSION CONTROL

Apollo 8, Houston, over. Apollo 8, Apollo 8, this is Houston. Apollo 8, Houston, over.

APOLLO ASTRONAUT

Houston, this is Apollo 8. Burn complete.

MISSION CONTROL

Roger, good to hear your voice.

NARRATOR

The burn worked. Behind the moon, the computer oriented the spacecraft and fired the engine at just the right moment for just the right time.

MINDELL

60 by 170 miles is the elliptical orbit they want to end up in. And they end up with, like, 60.5 and 169.9 miles. I mean, it's incredibly close, super-accurate burn.

NARRATOR

Over the next 20 hours, Apollo 8 will circle the moon ten times. It's Christmas Eve. Before leaving the moon, they'll show millions on Earth the view out the window with a live television broadcast that almost never happened.

BORMAN

I was against it. I didn't even want to take a television camera. I was stupid. Fortunately, the people at NASA overruled me, because the American people and the people on the earth had every right to see what we were seeing.

NARRATOR

But what should they say while showing the view?

BORMAN

I was told, "While you're in orbit around the moon "on Christmas Eve, "you'll have the largest audience that's ever listened to a human voice." I said, "Gee, what do you want us to do?" The response was, "Do something appropriate." I'll never forget that. Can you imagine that happening today? We thought, "Can we change the words to 'The Night Before Christmas'? "You know, make it more contemporary? How about something in the way of 'Jingle Bells'?" Nothing that we could come up with seemed appropriate. We ask each other, we ask our wives, we ask friends.

NARRATOR

In the end, it's Christine Laitin, Washington insider and wife of writer Joe Laitin, who has the answer.

BORMAN

And she said, "Well, why don't you start at the beginning?" And he said, "What do you mean?" She said, "Genesis."

ANDERS (on radio)

For all the people back on Earth, the crew of Apollo 8 has a message that we would like to send to you. "In the beginning, God created the heaven and the earth. And the earth..." I don't think anybody knew they were going to do that. "And God divided the light from the darkness.

LOVELL (on radio)

"And God called the light day, and the darkness He called night." One of the most memorable things in my life, I guess. It was very powerful.

BORMAN (on radio)

"'...and let the dry land appear,' and it was so."

AARON

The hair stood up on the back of my neck. The first impression I had was, "How appropriate."

BOSTICK

What could be better than having the first human beings, Americans, circling the moon on Christmas Eve, and they read the story of creation from Genesis? I mean, it brought tears to my eyes.

BORMAN (on radio)

"...God saw that it was good." And from the crew of Apollo 8, we close with good night, good luck, a Merry Christmas, and God bless all of you, all of you on the good earth. Wow! (laughs) It just drained me.

NARRATOR

For millions on Earth, the Christmas Eve television broadcast is the defining moment of Apollo 8. But for the engineers, and especially the astronauts, there's a critical maneuver just ahead

that overshadows everything else

coming home. "Trans-Earth Injection" is the engine burn that will send Apollo 8 out of lunar orbit and back toward Earth.

LOVELL

We're captured by the moon. That means that unless that engine works to get us out of here, we can be here for a lot longer. Is that engine going to work again?

NARRATOR

There's only one engine-- no backup. It has baked in sunlight 250 degrees above zero, frozen in darkness, 250 below.

BOSTICK

If the nozzle on the engine somehow overheated, or cracked, or something, there's nothing you can do about that. You lose the crew.

NARRATOR

Again, the burn will be controlled by the computer Again, they lose radio contact. (radio static popping, ends abruptly) No one on the ground will know if it worked until they acquire signal.

NORTHCUTT

Just watching that clock and wondering what happened when they were on the back side of the moon. What happened?

MISSION CONTROL

Apollo 8, Apollo 8, this is Houston. Apollo 8, Houston, over.

APOLLO ASTRONAUT

Houston, Apollo 8. Please be informed there is a Santa Claus. (laughter)

MISSION CONTROL

You're the best ones to know.

NARRATOR

Again, the engine worked. For the next two-and-a-half days, Apollo 8 will coast toward Earth. Navigator Jim Lovell updates their position with space sextant and DSKY. So far, it's been flawless. But MIT software engineer Margaret Hamilton has a nagging worry. How to prevent errors.

MINDELL

What if the astronaut types something wrong into the DSKY?

HAMILTON

My daughter Lauren would come in often and would play astronaut. And so she'd start pressing keys. And I remember one time, all of a sudden... (machine powers down, beeping) big crash, everything stopped. So I'm thinking, "What did she press? She had selected P01 during flight.

NARRATOR

"P01" tells the computer that it's back on the launchpad, waiting to start the mission. If an astronaut enters that into the DSKY during flight, the computer will forget where they are in space.

HAMILTON

This could happen on a real mission. We have to stop the astronaut from being able to select P01 during flight.

MINDELL

And NASA said, "You know, these are the most highly trained test pilots "in the world. They're never going to make a mistake."

NARRATOR

But, of course, they do. A day-and-a-half away from Earth, Jim Lovell is using the space sextant and DSKY to update their position.

ANDERS

Suddenly, Lovell said, "Uh-oh!"

MINDELL

Lovell is doing a star sighting, and he's entering, "Star number one." And by mistake he enters, "Program number one."

LOVELL

I got into a program that essentially told me I was back on the launch site waiting to take off.

ANDERS

Borman wakes up. "What's going on here?"

NARRATOR

The computer starts trying to reposition the Command Module, thinking they're back at Cape Canaveral.

BORMAN

The thing started turning and this, and Anders didn't know what was going on. Oh, he was mad that he could... (laughs) I don't know, he's, "Lovell, you lost it. You lost it!" I said, "Well, don't worry about it."

NARRATOR

Using the space sextant, Lovell orients the navigation system again, putting it back on track.

BORMAN

Just one of those things, you know, you can never trust an Annapolis graduate very far.

NARRATOR

A day and a half later, Apollo 8 reenters the earth's atmosphere at nearly seven miles per second. Ten minutes after that, on December 27, 1968, they splash down into the Pacific Ocean. (applause) The Saturn V rocket, the redesigned command module, the guidance computer all have worked perfectly. (cheers and applause)

BOSTICK

We accomplished just about everything that you need to do to land on the moon except the landing itself. (cheers and applause)

MINDELL

This is the moment that the Space Race ends. (applause) Once we do Apollo 8, the Soviets are out of the running.

NARRATOR

Seven months later, Neil Armstrong and Buzz Aldrin are walking on the moon, thanks in large part to Apollo 8.

COLLINS

Apollo 11 walked on the moon. Apollo 8 was about leaving. If you consider the leaving and the arriving-- both of them necessary steps-- I think the two flights were about equal in their historical significance.

NARRATOR

The legacy of this overlooked mission is profound. Of all the Apollo technologies, perhaps the one that touches more of us in our everyday lives than any other is its pioneering computer.

MINDELL

This was a major moment in the role of computers in the world, and computers being able to let us do things that we can't do any other way.

NARRATOR

With its DSKY and guidance computer, Apollo paved the way for keyboards, mice, touch screens, computer-controlled airliners, factories, smart phones, and more. Now we have digital computers in everything; this was the first digital computer in almost anything. Now we stake our lives on software. This was the first time people staked their lives on software. Yet it's an old, analog technology that gives us the most profound legacy of Apollo 8. Assigned to photograph future landing sites on the moon, Bill Anders is stunned by something else that's completely unexpected. When the earth came up in earthrise, I didn't even have a light meter. You know, I just started clicking away and changing the f-stops, and fortunately one of the pictures came out.

AARON

That picture is probably the picture of the century. We thought we were going there to study the moon. No! We went to the moon, we learned a lot about the moon, but most of all we learned about a new way to look at the earth.

BORMAN

The sense of isolation and closeness of our humanity; I wish more people would focus on it.

NORTHCUTT

Having that unifying experience, I think, was a very profound and moving moment for people on Earth to realize, "We're all on this one spaceship together, we'd better start taking care of it."

NARRATOR

Before, all this-- seeing our home planet as it really is and everything else; the rocket, the computer, leaving Earth-- had only been dreamed of. In December 1968, it became forever real on Apollo 8.

AARON

This was the mission that all that happened. To order this program on DVD, visit ShopPBS or call 1-800-PLAY-PBS. Episodes of "NOVA" are available with Passport. "NOVA" is also available on Amazon Prime Video.