SCE to AUX — The Call That Saved Apollo 12

“I can’t stand to be around anything that I don’t know how it works.”

The Lightning Strike

On November 14, 1969, Apollo 12 launched from Kennedy Space Center. Thirty-six seconds into flight, lightning struck the Saturn V rocket — twice. In Mission Control, every screen went haywire. Telemetry showed impossible readings. The spacecraft’s guidance platform tumbled. Fuel cells dropped offline.

Most flight controllers saw chaos. John Aaron saw a pattern.

The Man Who Couldn’t Stop Asking “Why?”

John Aaron was the EECOM (Electrical, Environmental, and Consumables Manager) on duty that day. Years later, in a NASA oral history interview, he explained what made him different:

“I think the thing I remember that really made a difference to me was, I was, just by my nature, I can’t stand to be around anything that I don’t know how it works. I’m always intrigued by knowing how it works or why it works. I will tend to dig into anything until I understand it.”

This wasn’t just personality — it was methodology. While other engineers became specialists in their assigned subsystems, Aaron obsessed over the connections between systems:

“Complexity comes in not so much in terms of how you handle it, not so much with what you know about a single subsystem… It’s the cross-cutting horizontal effects, where the real intrigue comes in, because it’s those interactions.”

The Night Shift That Changed Everything

Weeks before the launch, Aaron was working a third shift, monitoring a routine test of the command module at Kennedy Space Center. The technicians on duty — “not the A Team,” as Aaron put it — made an error and accidentally dropped all power on the vehicle.

The telemetry didn’t go to zero like it should have. Instead, Aaron saw squirrelly numbers: 6.7, 12.3 — a strange, specific pattern.

Most people would have helped fix the immediate problem and moved on. Aaron couldn’t let it go:

“I drove home that night, thinking where did those squirrelly numbers come from. And the next morning I came in the office and I sat down with Dick Brown, who was a North American engineer that worked in our office. We sat down and went through all the circuitry to find out just how does this thing work. Why would those pattern of numbers have come up?”

They traced it to an obscure power configuration: Signal Conditioning Equipment (SCE) to Auxiliary (AUX). A backup mode almost nobody knew existed.

Recognition, Not Calculation

When lightning struck Apollo 12, Aaron didn’t have time to diagnose the problem. But he didn’t need to — he recognized it:

“Well, never thinking that when lightning struck the vehicle on Apollo 12, that exact pattern showed up. So it wasn’t that I understood exactly what had happened, I recognized a pattern and how to get out of it.”

Aaron called out three words: “SCE to AUX.”

Flight Director Gerry Griffin had never heard of it. Neither had CapCom Jerry Carr. But astronaut Alan Bean, sitting in the Command Module, remembered a small switch he’d studied during training. He flipped it.

Telemetry restored. Mission saved.

Luck and Preparation

Aaron was honest about the role of luck:

“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 luck only works when you’ve done the preparation:

“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.”

Beyond Technical Curiosity

What made Aaron exceptional wasn’t just his technical knowledge — it was his curiosity about everything, including how people and organizations work:

“I was fascinated very early by how an organization could manage a program as big as these programs were, so I was always interested in how the dynamics of management worked, how people interact, what verbal communication skills worked and which didn’t.”

This cross-domain curiosity served him throughout his career:

“I could explain the software, what I was trying to do on the software side, in their language… They got to where they would always come to me because I could talk to them in their language.”

The Lesson

Someone once observed Aaron in meetings:

“You know, John, you listen just as intently to the subject that you knew that’s totally out of your expertise, as you did to the discussion we had about your subject.”

That’s the lesson of SCE to AUX: Stay curious about things outside your immediate concerns. The random detail you investigate tonight might save everything tomorrow.

Source: NASA Johnson Space Center Oral History Project, John W. Aaron interview, January 18, 2000

Why This Story Matters to Liana Banyan

At Liana Banyan, we build systems with the same philosophy: understand the cross-cutting effects, document the edge cases, and prepare for scenarios nobody has simulated yet.

Our Foundation Documents are written with this same obsessive transparency — not because we expect disaster, but because when complexity emerges, pattern recognition beats panic every time.

The code SCE-TO-AUX is a valid entry in our Hofund system — a nod to John Aaron and everyone who stays curious about things outside their immediate job description.

“Natural curiosity is a thing that probably motivated me to go understand these vehicles to that level, so that when lightning strikes Apollo 12… you prepare yourself for that kind of event.”

— John W. Aaron, NASA Flight Controller