The 1969 Apollo 11 circuit breaker fixed with a felt-tip pen

NASA spent billions on peak 1960s tech, only for the Apollo 11 mission to nearly end because Buzz Aldrin’s bulky suit snapped a tiny plastic switch. That switch was the "start button" for the engine they needed to get home.

Without it, they were looking at a permanent lunar residency. It’s the ultimate "oops" moment when the most advanced machine ever built is defeated by a clumsy elbow and a lack of legroom.

The fix? A felt-tip pen. Aldrin jammed it into the broken circuit breaker to flip the connection. A piece of stationery saved them from becoming permanent moon ghosts, proving that sometimes, office supplies are more reliable than rocket science.

Wait, why was the 'start button' just a tiny, breakable plastic stick?

It’s the ultimate engineering facepalm. That "button" was actually a circuit breaker toggle—a thin piece of plastic designed to save weight, because in space, every ounce is a literal fortune.

NASA spent years obsessing over heat shields and fuel ratios, but apparently, no one considered that putting a fragile plastic stick in a cramped cabin with men wearing rigid, pressurized suits was a recipe for disaster.

It was basically a high-stakes game of Operation, except instead of a buzzing nose, the penalty for touching the sides was starving to death in a silent, silver tomb.

So how does a cheap pen actually mimic a high-tech engine switch?

Think of that circuit breaker like a tiny drawbridge. When the plastic handle snapped off, the bridge was stuck in the 'up' position, meaning no power could reach the engine's ignition.

Aldrin didn't need the fancy plastic toggle; he just needed something small that wouldn't zap him to reach into the slot and manually shove the metal contact back into the 'closed' position.

It’s the ultimate insult to engineering. You build a multi-million dollar spacecraft, and its 'on' switch is so basic that a cheap office supply can do its job.

Couldn't he have just used his pinky finger to shove the metal back?

That is a fantastic way to turn a moon landing into a Viking funeral. The circuit was live, and sticking a conductive, sweaty human finger into a high-voltage gap is basically volunteering to be the spacecraft's newest fuse.

Even if he didn't get fried, there was the 'exploding human' problem. His suit was pressurized; one tiny snag on a sharp metal contact would have turned a small leak into a catastrophic depressurization. Not exactly the 'giant leap' NASA had in mind.

The pen was the perfect sacrificial lamb because its plastic casing is an insulator. It let him bridge the gap and trigger the engine without the electricity deciding to take a detour through his heart.

Hold on, why would NASA even let them bring a cheap marker into space?

That pen was a Duro Marker, basically a 1960s Sharpie. It wasn't packed for life-or-death emergencies; the crew just needed a simple way to label equipment or scribble notes on the cabin walls during the flight.

It’s a hilarious contrast. While the public was fascinated by the high-tech "Space Pen" that could write in zero-G, this humble, plastic marker ended up being the most critical piece of hardware on the ship.

Usually, space redundancy involves backup computers and extra fuel tanks. In this case, the ultimate backup "engine starter" was just a piece of stationery originally meant for marking storage bins.