Dear readers,

Half a century ago this week, a young NASA engineer spoke what would become one of the most celebrated bits of jargon in the history of the space program. Late in the morning of Nov. 14, 1969, just minutes after Apollo 12's Saturn V rocket took off, the spacecraft encountered a major problem. Back at Mission Control in Houston, the young engineer suggested relaying the seeming-nonsense phrase: "Try SCE to AUX."

You can find it on today t-shirts and coffee mugs. You can even find it in a variation of the famous British keep-calm dictum: "Keep calm and try SCE to AUX." The term is a knowing nod to history for space nerds, but it was one of NASA's most dramatic moments. In honor of the anniversary, below is an excerpt from my young-adult book Disaster Strikes, based on my "Countdown" podcast for TIME, recounting that harrowing morning:

Pete Conrad had no business trying to fly to the moon today. And NASA, by the look of things, had no business agreeing that it would be a good idea to send him there. You wouldn’t know that, however, from the scene at Cape Canaveral.

The Saturn V moon rocket was poised on the launch pad, impossible to miss even three miles away—a spike of white, 36 stories tall, weighing six-and-a-half million pounds. Vapor was subliming from the rocket’s sides.

Conrad, the commander of the mission, and his crewmates Dick Gordon and Al Bean had already made their ceremonial pre-flight appearance, sealed in their spacesuits as they took the short walk from the suit-up building to the waiting van for the long ride to the pad. Out of the view of the public, they had taken the 360-foot elevator ride to the top of the rocket and climbed inside their conical command module.

It was all as orderly and deliberate as the Apollo missions that flew before had been—and yet there was the business with the weather. The cloud ceiling was hanging at just 1,000 feet. The wind was blowing at just less than 20 miles per hour, barely within limits. The rain, at least, was only intermittent, but it was falling all the same.

Still, the NASA meteorologists gave the mission a cautious go, and five minutes before launch, the pad controller radioed the cockpit, wishing Conrad and his crew a good trip.

Gordon answered: “Hold off the weather for five more, will you?”

Conrad, a Naval aviator and test pilot, had no such worries. “The Navy is always glad to do the all-weather testing,” he said.

At 11:22 AM, the countdown clock wound down to zero and the engines lit, producing 7.5 million pounds of thrust.

Apollo 12 lifts off
Apollo 12 lifts off.

“Liftoff! The clock is running,” Conrad called as the Saturn V muscled itself off the pad and the mission clock on the instrument panel began to move.

Conrad, Gordon and Bean had been as prepared as they could be for the shaking and noise of a Saturn V launch, but the simulators in which they trained could never match the violence of the real thing.

“This baby is really going!” Conrad called over the roar.

“Man is it ever!” Gordon agreed.

“That’s a lovely liftoff! Not bad at all!” Conrad enthused.

It stayed lovely too—but only for another 15 seconds or so.

Then, just 37 seconds after launch and a mile and a half into the sky, a flash of light and a loud bang exploded through the cockpit.

“What the hell was that?” Gordon exclaimed.

Instinctively, all three astronauts looked toward the instrument panel, and what they saw shocked them. From one side of the big board to the other, the vital signs of their spacecraft were falling apart. Fuel cells flashed red, electrical systems spiked and failed; guidance programs, on-board computers, life support systems—basically anything dependent on electricity, which meant everything—began to crash. Worst of all, the four gyroscopes, together known as the guidance platform, went completely offline, meaning that the guided missile that was the Saturn V was in danger of becoming completely unguided.

“OK, we just lost the platform, gang,” Conrad radioed to the ground. “I don’t know what happened here; we had everything in the world drop out."

Conrad’s left hand was resting on the spacecraft abort handle. In the event of a launch disaster, it was the commander’s call to end the mission and save his crew, activating the escape rockets which would pull the Apollo capsule up and away from the from the Saturn V and sending the crew to a safe parachute descent in the Atlantic.

That, of course, would mean the end of a half-billion dollar rocket and the end too of what was supposed to be a 10 day lunar mission after less than ten minutes.

For the moment, the commander kept his hand still.

Conrad’s counterpart in Mission Control was Gerry Griffin, a former guidance and navigation officer who had recently been promoted to Flight Director. Griffin toggled his microphone open and spoke directly to John Aaron, the 24-year old engineer sitting at what was known as the EECOM console, for electrical, environmental and consumables.

“How’s it looking EECOM?” he asked. He got no answer. “EECOM, what do you see?” he repeated.

Apollo 12 1969 Mission Control
View of NASA's Mission Control Center during Apollo 12's flight to the moon.

What Aaron was seeing was not good—the same ratty data all of the other controllers had on their screens. Like the other controllers, he had never seen anything like it before—or almost never. Aaron had a reputation as something of a wünderkind in Mission Control, with an uncanny way of remembering nearly any glitch that had ever affected any rocket that had been placed in his care before.

He now recalled a moment a couple of years earlier, when he was manning a console during a simulated launch of a smaller, unmanned Saturn 1B rocket. That day he’d seen similarly screwy numbers on his screen—too screwy to be believable—and he guessed the problem could be traced to what was known as the Signal Conditioning Equipment, or SCE, which was designed to translate the signals coming from the electrical system into usable data that the controllers and astronauts could read. If the system failed, switching it from its primary mode to its auxiliary mode could reboot the SCE itself and also bring the entire electrical system back online if it had gone off.

The SCE was so rarely used, however, that almost nobody knew what it was. Even in the spacecraft, the switch was installed in an entirely obscure spot, off to the far right of the instrument panel, over Al Bean’s shoulder.

“Flight, EECOM, try SCE to AUX,” Aaron said to Griffin.

“Say again, SCE to off?” Griffin asked.

“AUX,” Aaron repeated. “Auxiliary, Flight.”

Griffin then radioed the command to the capsule communicator, or Capcom, who radioed it up to the ship.

“Apollo 12, Houston. Try SCE to Auxiliary. Over,” he said.

Conrad scowled. “FCE to auxiliary? What the hell is that?”

“SCE,” the Capcom corrected.

Conrad and Gordon did not know where to begin looking for the switch, but Bean, the one rookie aboard, did. He reached up behind himself and threw it to the new setting. Straightaway, the sickly lights and numbers on the instrument panel and the screens in Mission Control began to get well.

“It looks…everything looks good,” Bean said tentatively.

Aaron sighed in relief; Griffin, who had been standing, dropped back in his seat.

“Ok, we’ll straighten out our problems here,” Conrad said as the rocket sped on toward space. “I don’t know what happened; I’m not sure we didn’t get hit by lightning.”

That was exactly what happened. As the Saturn V passed through the electrically charged clouds, it turned itself into a lightning rod, attracting a flash that passed through the rocket and ran all the way down its exhaust trail to the ground. With the electrical system reestablished, Apollo 12 reached Earth orbit, spent the next three hours there configuring itself and making it was sure it was fit for its mission, then lit out for the moon.

On November 19 it landed on the moon's Ocean of Storms. Conrad and Bean would take two moonwalks over the course of the next day, while Gordon staton-kept in the orbiting command module. On November 24, ten days after the launch and the lightning strike, the crew would safely splash down in the Pacific Ocean. Conrad and Bean would fly once more, serving aboard the Skylab space station. Gordon never returned to space.

And John Aaron, who had learned a lot about how to handle a real-time emergency and would be well-prepared to do so again if the occasion ever arose, would go straight back into training for NASA's next great lunar mission: Apollo 13.

—Jeffrey Kluger


Copyright © 2019 by Jeffrey Kluger, from Disaster Strikes: The Most Dangerous Space Missions of All Time. Used by permission of Philomel Books, an imprint of Penguin Random House LLC.


One more bit of history from Apollo 12: When the astronauts were returning from the moon after their liftoff from the Ocean of Storms on Nov. 20, 1969, they captured something never before seen: a solar eclipse created not when the moon moved between the sun and the Earth, but when the Earth moved between the sun and the spacecraft. Human beings have not been in a position to see such a thing since Apollo 17, the final lunar mission, flew back to Earth in December 1972. NASA hopes to change that with a return to the moon in 2024.


SpaceX gets it right—and heaves a sigh

It's never a good thing when the lifesaving emergency engines that are supposed to blast a spacecraft away from an exploding rocket instead explode themselves. That's what happened in a fortunately uncrewed test of a SpaceX Dragon spacecraft last April. NASA Administrator Jim Bridenstine, as we reported here last week, was decidedly displeased, and SpaceX was further embarrassed when Boeing, which is also building a crew vehicle for NASA, recently aced its abort-rocket test. Now, SpaceX too has gotten it right, successfully conducting a test of its escape engines on a launch stand at Cape Canaveral earlier this week.

Someone stop that star

You may never have heard of the Southern Stellar Stream Spectroscopic Survey (S5), an ongoing sky study being conducted by the Siding Spring Observatory in New South Wales, Australia, but it's time to pay it some mind. That's because of an astonishing discovery the survey team just made of a hypervelocity star, which, as the label suggests, is a type of star that moves really, really fast—more than 1.6 million km per hour (1 million mph), usually after being gravitationally jettisoned from their home galaxy by a black hole. The S5 team just announced the discovery of a new stellar speedster, moving at a blistering 3.7 million km per hour (2.3 million mph), having been spun off by the black hole at the center of our own galaxy. SciNews has a good read on how the discovery was made and what its significance is. And for those with the scientific grit for it, the paper itself is here, in Monthly Notices of the Royal Astronomical Society.

New name solves a nasty problem

There was a lot of happy high-fiving on Jan. 1, 2019 when the New Horizons spacecraft flew by the Kupier Belt object known as MU69, which, at 6.6 billion km (4.1 billion miles) from Earth, is the most distant body ever reconnoitered by a spacecraft. The object was nicknamed Ultima Thule, or "beyond the known world," which describes it well and, not insignificantly, sounds kind of cool. Only it's not. Indeed, it's deeply uncool. Ultima Thule turns out also to be the name of the mythical world that the early 20th-century German group known as the Thule Society claimed was the origin of the Aryan people. And the Thule Society later flowed directly into the German Workers' Party, which later became known as the Nazi party. So: not good. NASA thus wisely (and quickly as these things go), announced that it was changing the official name of MU60 to Arrokoth, or sky in the language of the Native American Powhatan language. A sweet name—and a wise move.

Slow boat home

You could be forgiven for missing the liftoff of Japan's Hayabusa 2 spacecraft from the surface of the asteroid Ryugu on Nov. 13. You could even be forgiven for missing it if you'd been standing directly on the one-kilometer-wide rock. Hayabusa 2's launch, after all, was nobody's idea of a blastoff, moving at just 10 centimeters per second. But the ship will speed up soon, thanks to its ion thrusters, and will cover the 253 million km (157 million miles) from Ryugu to Earth by the end of next year, bringing with it samples from the surface of the asteroid.

Bones on Mars

Fossil hunters have been digging up remains of extinct species on Earth for centuries. Now the work is about to begin on Mars. A paper just published in the journal Icarus announced the identification of a ring of mineral deposits in the Jezero crater, which will be the landing site of the Mars 2020 rover, set for launch next year. The ring is rich in carbonates, the stuff of fossils and sea shells. The deposits could wind up being nothing but carbonates—or they could be a whole lot more. We'll know soon enough.


"SCE to AUX" isn't NASA's only fun jargon-y phrase. Below are a few others we're into. Which is your favorite? (Oh, and definitely send us others you like that aren't on the list!)

A) "Go for TLI" (TLI stands for "translunar injection," and the phrase means "you are go to accelerate out of Earth orbit." Spoken first on Apollo 8.)

B) "Eagle, you are Stay for T1" (This is what Charlie Duke at Capcom said to Neil Armstrong and Buzz Aldrin, once they landed on the moon, clearing them to stay for the moonwalk.)

C) "The clock has started" (The first words after liftoff, meaning the mission has officially begun. It refers to a literal clock on the instrument panel. It was spoken first 5/5/61, by pioneering astronaut Alan Shepard.)

D) "Try SCE to AUX" (You know all about this one now.)

Send your answers to us at space@time.com.


TIME Space is written by Jeffrey Kluger, Editor at Large at TIME and the author of 10 books, including Apollo 13, Apollo 8 and two novels for young adults. Follow him at @jeffreykluger.

We welcome any feedback at space@time.com.

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