Apollo's Daring Mission

PBS Airdate: December 26, 2018

NARRATOR: Apollo 8: a last-minute change sets a mission on a dangerous new course…

JERRY BOSTICK: (Mission Control, Apollo 8): I said, “What? That’s the craziest idea I ever heard.”

WILLIAM “BILL” A. ANDERS (Pilot, Apollo 8): …a lot of risk.

NARRATOR: …untried technologies, put to the test.

MICHAEL “MIKE” COLLINS (Mission Control, Apollo 8): Any one of them can be a disaster, if it doesn’t go perfectly well.

NARRATOR: It’s the height of the Cold War; two superpowers race to the moon.

BILL ANDERS: They were beating us at every turn.

FRANK BORMAN (Commander, Apollo 8): I wanted to be part of winning.

NARRATOR: A president’s deadline looms.

JOHN F. KENNEDY (President of the United States, 1961–1963/May 25, 1961, Speech to Congress/File Footage): …landing a man on the moon… …before this decade is out.

DAVID MINDELL (Author, Digital Apollo: Human and Machine in Spaceflight): There’s just enormous pressure.

NARRATOR: Then, tragedy strikes.

EDWARD H. WHITE (Apollo 1 Astronaut/File Footage): 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.

NARRATOR: A half-century later, the legacy of this audacious journey affects us all. The mission that got us to the moon, Apollo’s Daring Mission, right now, on NOVA.

NEIL ARMSTRONG (Apollo 11 Astronaut/Walking on the Moon/File Footage): I’m at the foot of the ladder.

NARRATOR: It is perhaps the greatest technological feat in history…

NEIL ARMSTRONG (Walking on the Moon/File Footage): I’m going to step off the LEM.

NARRATOR: …humans arriving at another world.

NEIL ARMSTRONG (Walking on the Moon/File Footage): That’s one small step for (a) man; one giant leap for mankind.

NARRATOR: Yet before the arriving could happen, first, there was the leaving. It’s December, 1968. A space mission unlike any other begins, Apollo 8.

FRANCES “POPPY” NORTHCUTT (Apollo 8 Return-to-Earth Specialist): It was the most dangerous mission of all.

JERRY 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.

MIKE 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 10 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 only flown once, on Apollo 7, a mere 180 miles off Earth’s surface. Apollo 8 will take these untried technologies on a half-million-mile roundtrip, in the ultimate test.

BILL ANDERS: We probably had one chance in three of making a successful flight, and 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.

All right Houston, you are “GO” for staging, over.

NARRATOR: It is a giant risk. But originally, Apollo 8 was supposed to be a baby step, just another test flight around the earth.

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

BILL 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 “JIM” A. LOVELL (Navigator, Apollo 8): We were training in California, the three of us, Bill, myself and Frank, when, suddenly, Frank got called back to Houston.

FRANK 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.

FRANK BORMAN: 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? And so, I went back to Houston, and he said, “Close the door.” So, I realized that something was big.

NARRATOR: A C.I.A. spy satellite has photographed an enormous Soviet rocket on a launch pad. It can mean only one thing.

FRANK BORMAN: The C.I.A. 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. For years, the U.S. and Soviet Union, both armed with nuclear weapons, have been locked in a deadly Cold War.

DEBORAH G. DOUGLAS (Historian, Massachusetts Institute of Technology Museum): 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.

DEBORAH DOUGLAS: Yuri Gagarin, Valentina Tereshkova…blow after blow, after blow.

BILL ANDERS: 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 (Computer Engineer, Massachusetts Institute of Technology Instrumentation Lab): He said, “Guys, find me something we can beat the Russians at.”

JOHN F. KENNEDY (May 25, 1961, Speech to Congress/File Footage): 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.

NARRATOR: Kennedy has set a firm deadline: the end of the 1960s.

JERRY BOSTICK: It was a simple, one sentence statement: the goal and the schedule, clear, succinct; no fuzz on that goal.

FRANK BORMAN: I never joined NASA to explore space. You know, basically I was a military person, and it was clear to me that we were in a serious confrontation with the Soviets. I wanted to be part of winning.

NARRATOR: Military test pilots, now “astronauts,” begin flying in 1961. By 1967, Americans have mastered the basics of spaceflight 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.

Three weeks before launch: a dress rehearsal on the ground, a practice countdown. It’s January 27th, 1967; a Friday. Things are not going well.

APOLLO 1 MISSION CONTROL ENGINEER (January 27, 1967/Audio File Footage): Ah, who’s transmitting?

GUS GRISSOM (Apollo 1 Command Pilot/Audio File Footage): This is the Command Pilot, do you read me?

JOHN AARON (Mission Control, Apollo 8): It was the end of a very frustrating day.

APOLLO 1 MISSION CONTROL ENGINEER (January 27, 1967/Audio File Footage): You’re pretty garbled here, Gus.

JOHN AARON: They were having communication problems with the crew.

GUS GRISSOM (File Footage): How are we going to get to the moon, if we can’t talk between three buildings?

ED WHITE (File Footage): They can’t hear a thing you’re saying.

GUS GRISSOM (File Footage): Jesus Christ!

JOHN AARON: When all of a sudden, I thought I heard “fire!”

ED WHITE (File Footage): Hey! We’ve got a fire in the cockpit!

NARRATOR: The fire quickly becomes an inferno.

JOHN AARON: And, you know the rest is history.

NARRATOR: With no chance of escape, poisoned by toxic fumes, three astronauts perish.

JERRY 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.

DAVID 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, 5,000 images in all. Sifting through these artifacts, the Apollo Review Board pieces together what went wrong.

FRANK 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 (Computer Engineer, Massachusetts Institute of Technology Instrumentation lab): 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.

JOHN 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.

JIM 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.

JOHN AARON: It caused NASA to stop and reflect on everything it was doing, and redo it.

RAMON ALONSO: But for the fire, there wouldn’t have been the reexamination of all kinds of things.

JERRY BOSTICK: We redoubled our efforts. We said, “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.”

DAVID MINDELL: 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.

NARRATOR: It will weigh over 6,000,000 pounds, stand as tall as a 36-story building and be able to lift a hundred-and-thirty 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.

The Saturn V will be the biggest ever built, if it can be built. To get this enormous machine off the ground will require a new engine, 10-times more powerful than any ever designed. It will be called the F-1.

Sonny Morea is Project Manager, in June, 1962, when NASA test fires its first F-1.

SONNY MOREA (Apollo F-1 Engine Project Manager): When we tried to fire it for the first time, it just blew apart.

NARRATOR: As F-1 engines keep blowing up, engineers finally identify the problem: “combustion instability,” uneven burning.

SONNY MOREA: 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.

Well, that same phenomenon happens in an F-1 engine, but they don’t flip at five times in a second; 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.

SONNY MOREA: The solution had to come by trial and error.

RON TEPOOL (Apollo F-1 Test Engineer): You know, you find a way, or make one. That’s the way it was back then.

SONNY MOREA: It was absolutely the seat of our pants.

NARRATOR: If they can’t fix the F-1, Apollo is finished.

SONNY 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.

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 shower head. 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.

SONNY 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, eventually, they get the engine to run smoothly.

SONNY MOREA: And 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?

SONNY MOREA: 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.

NARRATOR: 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.

RON TEPOOL: That would drive the engine unstable, and it would dampen out right away, where before, it wouldn’t.

SONNY MOREA: And every single time, those baffles dampened out the oscillations.

NARRATOR: In November, 1967, two years and one month before Kennedy’s deadline, the Saturn V rocket has its first unmanned test flight.

MIKE 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.

MIKE COLLINS: When the engines ignited, it didn’t seem like a big deal, and then the shockwave came. 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.

DEBORAH DOUGLAS: 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?

NARRATOR: To hit the moon, NASA turns to Charles Stark Draper, better known as “Doc,” engineer, aviation pioneer, M.I.T. professor.

MIKE COLLINS: Stark Draper was the leader of the instrumentation lab at M.I.T., 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…

DRAPER: On inertial and transfer power.

NARRATOR: “inertial” navigation.

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. Gyroscopes and accelerometers are mechanical devices; each day, a little bit of error creeps in.

HUGH BLAIR-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.

HUGH BLAIR-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 M.I.T. thinks that’s too hard for a human pilot; it can all be done by a computer.

DAVID 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.

DAVID 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.”

RAMON 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.

HUGH BLAIR-SMITH: So, you better have 17 fingers and be awfully, awfully agile.

NARRATOR: 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.”

DAVID 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 (Software Engineer, Massachusetts Institute of Technology Instrumentation Lab): 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.

DEBORAH DOUGLAS: Computers 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.

MARGARET 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.

RAMON 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, “All right, here’s a cubic foot, fill it with computer.”

DAVID MINDELL: “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.

HUGH BLAIR-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 percent reliable.

As the summer of 1968 arrives, barely 18 months remain until the Kennedy deadline. Then, the C.I.A. 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.

JERRY BOSTICK: I said, “What? That’s the craziest idea I ever heard.”

NARRATOR: Chris Kraft, director of Mission Control, orders engineer Jerry Bostick to study the possibility.

JERRY 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.

JERRY 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.

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

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

JIM LOVELL: Well, I thought that was a grand idea. This was exploration; this was a mini Lewis and Clark expedition.

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.

SONNY 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, 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.”

NARRATOR: Now, Apollo 8 will go. It’s December 21, 1968.

JIM 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.

BILL ANDERS: First on the Saturn V, first to leave the earth, first to go into lunar orbit—a lot of risk.

JOHN AARON: Was I nervous? Yes, I was nervous! That’s a big step, a big step.

APOLLO 8 MISSION CONTROL: Ten, nine…

NARRATOR: Eight seconds to go…

APOLLO 8 MISSION CONTROL: We have ignition sequence.

NARRATOR: …fuel starts pumping, fifteen tons each second. The F-1 engines come alive.

BILL 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.

FRANK 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 seatbelts and then back, as the second stage took over.

NARRATOR: Eleven-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 T.L.I., “trans-lunar injection.”

MIKE 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.

MIKE COLLINS: I mean, I love NASA, but they have an ability to transform, sometimes, the ethereal into the mundane.

NARRATOR: In this moment, Michael Collins has the honor of announcing a turning point in human history.

MIKE COLLINS: I said to them, “Apollo 8, you’re “GO” for T.L.I.”

(File Footage): Apollo 8, you are “GO” for T.L.I., over.

And Borman said, “Roger, Houston.”

FRANK BORMAN (File Footage): Roger, understand, we’re “GO” for T.L.I.

MIKE COLLINS: 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 T.L.I.”

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

DAVID 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.

JIM LOVELL: Our blunt slide was towards the moon, so we never saw the moon as we actually got right up to it.

NARRATOR: 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.

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

DAVID 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, touchscreen or keyboard, how will an astronaut talk to the computer?

M.I.T.’s answer is the Display Keyboard, or “DSKY.”

DAVID MINDELL: It has a numeric keypad and a very simple, what you would think of now as an L.E.D. display.

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

NEWS FOOTAGE: To see the Apollo guidance and navigational system in operation, we talk with Mr. Ramon Alonso.

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

RAMON 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. “DISPLAY TIME.” DISPLAY might be 16, and TIME would be 45.

MIKE 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.

JIM LOVELL: We were coming up to what is known as L.O.I., “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.

DAVID MINDELL: If you burn too much, you could go in too low an 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 L.O.I. burn happens when Apollo 8 is behind the moon. Radio signals will be blocked, all communication cut off.

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

FRANK 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,” L.O.S.

JOHN AARON: There was nothing to say. You, you’re just sitting there, and it’s quiet as a mouse.

APOLLO 8 MISSION CONTROL (File Footage): Apollo 8, Houston. One minute to L.O.S. All systems go. Safe journey, guys.

BILL ANDERS (File Footage): Thanks a lot, troops.

JIM LOVELL (File Footage): See you on the other side.

FRANK BORMAN: At the exact second we were supposed to lose communications, we lost it.

And I said something like, “Whew! We must be right on, right on time.”

BILL ANDERS: 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.”

FRANK BORMAN: They probably turned off the damn radio!

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

JOHN 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.

JIM LOVELL: We saw nothing…

FRANK BORMAN: We were upside down and backwards in perfect darkness.

JIM LOVELL: …until we rotated the spacecraft around.

FRANK BORMAN: Suddenly we looked down and there below us was the lunar surface.

JIM LOVELL: You know, we were like three school kids 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.

POPPY 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.

POPPY NORTHCUTT: It was dead silent, except for hearing the CAPCOM calling out, “Apollo 8, this is Houston; Apollo 8, this is Houston…”

APOLLO 8 MISSION CONTROL (File Footage): Apollo 8, Houston, over. Apollo 8, Apollo 8, this is Houston. Apollo 8, Houston, over.

JIM LOVELL (File Footage): Houston, this is Apollo 8. Burn complete.

MISSION CONTROL (File Footage): 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.

DAVID MINDELL: Sixty-by-one-hundred-seventy 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 10 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.

FRANK 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?

FRANK 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?

JIM LOVELL: 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.

FRANK BORMAN: 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.

FRANK BORMAN: And she said, “Well, why don’t you start at the beginning?” And he said, “What do you mean?” She said, “Genesis.”

BILL ANDERS (File Footage): 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…”

JOHN AARON: I don’t think anybody knew they were going to do that.

BILL ANDERS (File Footage): “And God divided the light from the darkness.”

JIM LOVELL (File Footage): “And God called the light, day, and the darkness, he called night.”

JERRY BOSTICK: …one of the most memorable things in my life, I guess. It was very powerful.

JIM LOVELL (File Footage): “And let the dry land appear, and it was so.”

JOHN AARON: The hair stood up on the back of my neck. The first impression I had was how appropriate.

JERRY 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.

FRANK BORMAN (File Footage): “…and 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 this good Earth.

JOHN AARON: Wow! 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.

JIM LOVELL: We’re captured by the moon! That means that unless that engine works to get us out of here, we could 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.

JERRY 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, and take place behind the moon.

APOLLO 8 MISSION CONTROL (File Footage): Apollo 8, this is Houston. Three minutes to L.O.S., over.

NARRATOR: Again, they lose radio contact. No one on the ground will know if it worked, until they acquire signal.

POPPY NORTHCUTT: Just watching that clock and wondering what happened when they were on the back side of the moon…what happened?

APOLLO 8 MISSION CONTROL (File Footage): Apollo 8, Apollo 8, this is Houston. Apollo 8, Houston, over.

JIM LOVELL (File Footage): Houston, Apollo 8. Please be informed there is a Santa Clause.

APOLLO 8 MISSION CONTROL (File Footage): 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 M.I.T. software engineer Margaret Hamilton has a nagging worry.

MARGARET HAMILTON: How to prevent errors.

DAVID MINDELL: What if the astronaut types something wrong into the DSKY?

MARGARET HAMILTON: My daughter Lauren would come in often, and would play astronaut. So, she’d start pressing keys. And I remember one time, all of a sudden, 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 launch pad, waiting to start the mission. If an astronaut enters that into the DSKY during flight, the computer will forget where they are in space.

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

DAVID 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.

BILL ANDERS: Suddenly, Lovell said, “Uh oh!”

DAVID MINDELL: Lovell is doing a star sighting, and he’s entering star number one. By mistake he enters “program number one.”

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

BILL 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.

FRANK BORMAN: The thing started turning and this…and Anders didn’t know what was going on.

JIM LOVELL: Oh, he was mad. I don’t know, “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.

FRANK 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.

The Saturn V rocket, the redesigned command module, the guidance computer, all have worked perfectly.

JERRY BOSTICK: We accomplished just about everything that you need to do to land on the moon except the landing itself.

DAVID MINDELL: This is the moment that the Space Race ends. 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.

MICHAEL 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.

DAVID 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.

DAVID MINDELL: 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.

NARRATOR: 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.

BILL ANDERS: 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.

JOHN 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.

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

POPPY 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.

JOHN AARON: This was the mission that all that happened.