A photograph later showed the initial lightning strike hitting the ground near the launch pad. Image: NASA
Unbeknownst to anyone, their spaceship had just become history's highest and fastest lightning rod.
Almost all of the warning lights on the instrument panel suddenly lit up like Christmas. Apparently, they reported, the Yankee Clipper's main power was gone.
Apollo 12 astronauts (left to right) Lunar Module Pilot Alan Bean, Command Module Pilot Richard Gordon, and Commander Pete Conrad relax during flight rehearsal in the Apollo mission simulator. Image: NASA
Alan Bean's first thought was that the capsule had disconnected from the rocket; but the G-forces on his body told him otherwise. Conrad radioed back to Houston: "I don't know what happened here, we had everything in the world drop out!"
In Houston, the stream of data coming out of the capsule was garbled. And without that data, there was little information with which to figure out what was happening. "Roger," was all Mission Control could say.
The astronauts approaching space and the engineers on Earth now had ninety seconds to decide whether to abort.
In that case, the astronauts would be separated from the rocket and hopefully land in the ocean, where they would be rescued, and the rocket and the nation's space dreams would be blown to smithereens. Hopefully.
Seconds passed; time slowed down. For the astronauts, it was literal: as they sped into space (at 60 seconds they would surpass the speed of sound), time was literally slowing down.
For an eternity of twenty seconds,
Big projects like launching a spacecraft often require quick thinking with a limited amount of information, conducted under an unearthly level of pressure. There are of course the simple human errors, like the little typo led to the detonation of a Mariner rocket in 1962, or the metric system mix-up that lost a Mars rover. Throw in one of spaceflight's biggest X factors—dangerous weather like lightning and cold snaps—and it's easy for tiny mistakes to turn catastrophic.
Since Mission Control had no access to the capsule's data, assessing the problem fell, in part, to the astronauts. Conrad's hand hovered near the abort lever. Procedures dictated that in the event of a power failure, the astronauts could abort the launch themselves. They could have tried to flip switches, in the hope that things would come back on.
"One of the rules of space flight is you don't make any switch-a-roos with that electrical system unless you've got a good idea why you're doing it," Bean explained later. "If you don't have power at all, you might change a couple of switches to see what will happen. When you have power and everything is working, you don't want to switch too much. I didn't have any idea what had happened. I wasn't aware anything had taken place outside of the spacecraft. I was visualizing something down in the electrical systems."
An unusual data readout appeared on John Aaron's monitor. Image: NASA
Miles below, John Aaron, a 24-year-old NASA engineer who hailed from Oklahoma, stared into his monitor and its garbled data.
Approximately fifty seconds after his screen had first scrambled, he calmly issued a suggestion to his Mission Control colleagues.
"Try SCE to Aux."
In his mangled data, Aaron had recognized a pattern. A year earlier, by sheer coincidence, Aaron happened to be in Mission Control during a launch pad simulation. And that night, he remembered, he had briefly noticed a similar set of gibberish on the screen, "some squirrelly kind of numbers," as he told a NASA interviewer later. He realized that the team handling systems that night had briefly dropped the capsule's voltage by accident.
This voltage change, he discovered, had effected a device called the SCE, or Signal Conditioning Equipment, which was responsible for converting raw signals from the craft's sensors to standard voltages so that information could be displayed on instruments and relayed back to Houston. By switching the SCE to auxiliary or backup power mode—Aux—Aaron remembered that the SCE would continue to operate under lower-voltage conditions, and the instruments would come back. At that point, the fuel cells could be restarted. In a matter of seconds, the solution came to him.
"SCE to off?" someone says on the NASA transcript. The switch was so obscure that neither of his bosses knew what he was talking about.
"What the hell's that," blurted out Gerald Carr, who was in charge of communicating with the capsule. The rookie flight director, Gerry Griffin, didn't know either.
Sixty seconds had passed since the initial lightning strike. No one else knew what to do. The call to abort was fast approaching.
Finally, Carr reluctantly gave the order in a voice far cooler than the moment.
"Apollo 12, Houston, try SCE to Auxiliary, over."
Now it was the astronauts' turn to puzzle. Conrad and Gordon were clueless. "FCE to Auxiliary—what the hell's that?" Conrad shot back. "NCE to auxiliary…"
“SCE, SCE to auxiliary” Carr corrected him.
There were over a hundred switches. Neither of them knew where that one was.
He threw it.
“SCE to AUX,” he radioed.
In the command module, the lights on the instrument panel calmed. Down at Mission Control, the data streams flipped to normal.
Aaron could now see it bright as day: the fuel cells had become disconnected. A few seconds later, Mission Control told Bean to reset them. Power returned. The launch continued as if nothing had happened. Brows were wiped.
"Now we're working out our problems here," said Conrad. "I don't know what happened. I'm not sure we didn't get hit by lightning!"
He added: "I think we need to do a little more all-weather testing."
"A-men," Houston responded.
Conrad chuckled. "That's one of the better sims, believe me."
"We've had a couple of cardiac arrests down here too, Pete."
"There wasn't any time for that up here," he replied. And then Conrad broke out in laughter.
"He laughed all the way into orbit," Aaron recalled.
Mission Control, two minutes after the initial event. Image: NASA
Conrad chuckled. 'I think we need to do a bit more all-weather testing.'
“God darn Almighty!" Gordon exclaimed. "Wasn’t that something, babe?”
"We're all chuckling up here over the lights," Bean said. "There were so many on we couldn't read em. [Long pause]"
“Well, I’ll tell you one thing," said Conrad, "this is a first-class ride, Houston."
From the Apollo 12 flight transcript
But there was still a decision to make. Despite the fresh power and the clean data, Mission Control still didn't know the damage to the spacecraft.
"We kept clicking off the checklist," Griffin remembered later, "and when we got to the end we all kind of said, 'We don't know where all that stray electricity have have run around in the cabin, but everything we can check looks okay. Is there any reason not to go?'
"We looked at each other and said, 'Hell no, let's go!'"
"Whoop-ee-doo!" Conrad replied. "We're ready! We didn't expect anything else."
"We didn't train for anything else, Pete," said Carr.
"I'll tell you, Jer," Gordon said, "we were just wondering if we'd trained for that launch, either."
But lift-off was just the beginning of Apollo 12's harrowing saga.
The harrowing return
Apollo 12 would hit the lunar surface on November 19, 1969, guided down by radar and computer to a landing a few meters from the Ocean of Storms, where the old Surveyor 3 robot spacecraft had soft-landed on the surface of the moon two years earlier. Everything proceeding beautifully.
But NASA managers had one lingering concern about Apollo 12's return to Earth: if the parachutes were indeed damaged, the capsule would violently smash into the Pacific Ocean and the crew would be killed instantly.
If we had [the astronauts] enter [the Earth] now they'd get killed earlier than if we sent them to the moon and let them do whatever else they're doing there and then come back 10 days later. And if their parachutes don't work then, well... At least they've had 10 days in a great adventure.
About an hour before the astronauts would enter Earth's orbit, "I think either Pete, Dick or I said, 'Well, I wonder how those parachutes are doing?' And then someone else said ... 'Well, we'll find out in about 55 minutes!'"
The capsule would land safely.
"We forgive the weather man for his job," Pete Conrad told them, "but had we to do it again, I'd launch under exactly the same conditions."
Lightning and lightning-fast thinking
Lightning has sabotaged at least two other NASA missions. During a launch on March 26, 1987, a cloud-to-ground lightning flash struck the unmanned Atlas Centaur 67, which was carrying a Naval communication satellite. The current apparently altered memory in the digital flight control computer, which resulted in the generation of a hard-over yaw command, leading to "an excessive angle of attack, large dynamic loads, and ultimately the breakup of the vehicle."
And, amazingly, during another 1987 launch, two sounding rockets resting on launch pads at NASA's Wallops Island were prematurely launched due to a lightning strike.
"Lightning is a very difficult thing to accurately measure because the phenomena associated with lightning tends to disrupt the instrumentation and corrupt the data that is trying to be captured," Gary Snyder, a specialist with NASA's lightning team, said in 2011. "Previous systems have historically produced erroneous data and have failed at the worst times."
If it hadn't been for the quick thinking of John Aaron (and the recall of Alan Bean), one of those lightning-induced failures might have thrown the entire lunar program off course, and possibly resulted in three deaths. Alongside the rescue of Apollo 13, the calm rescue of Apollo 12 was considered to be NASA's "finest hour."
"The quick response to the Apollo 12 outage came about not as a result of blind luck but of careful planning, training, and development of people, procedures, and data display techniques by those responsible for flight control," it read.
From a chapter on Apollo 12, in a 1972 NASA report titled "What Made Apollo a Success"
In 2000, weeks before his retirement from NASA,
an agency historian interviewed Aaron—who is
Aaron said that when he happened to notice a strange data signature during that launch simulation one night in 1968, his "natural curiosity" led him to better understand why that happened. He observed that, in preparing to get humans out of Earth's orbit and over to the Moon, and down, and collect rocks, and conduct science, and then up and back to Earth, NASA had never anticipated a lightning bolt.
"Our simulators were not even sophisticated enough that if we had, would it have necessarily produced the exact signature that I saw," he said. "So only just by your research and 'what if' and contemplation and thinking about things and try to think of all, do you prepare yourself for that kind of event."
John Aaron in the Apollo days. Image: NASA
It's digging in with that kind of curiosity of why things do what they do and how things interreact.
Aaron noted another ingredient in the lightning bolt affair, and in his lightning-fast intervention, and it was one that seemed to contradict NASA's findings.
"Luck plays a part," he said. "Now, it was not only luck that at a pad test I saw that, an inappropriate sequence was being executed in a pad test, it was also the luck that it would happen during the launch phase and that I was the flight controller. If you had had any other EECOM there, they didn't see that pattern. But it's digging in with that kind of curiosity of why things do what they do and how things interreact was the motivation for why I think I became a good flight controller."
Aaron's curiosity and some untold measure of luck would help him a year later, when he was called on to help rescue the nearly-doomed Apollo 13 mission. Aaron developed the innovative power-up sequence that allowed the Command Module to return to Earth on very limited power, and save another group of astronauts.
By that time, Aaron's "SCE to Aux" rescue had already become part of NASA legend, and earned him what was said to be the highest of the agency's nerdy, innuendo-rimmed compliments: the nickname "steely-eyed missile man."
Somehow, that just doesn't quite do justice to the man who saved Apollo from the ferocity of Zeus.
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