The one switch that saved Apollo 12 after a lightning strike
Apollo 12’s Saturn V was struck by lightning twice within the first minute of flight, causing telemetry to turn to garbage. Flight controller John Aaron recognized a low‑voltage failure pattern he had seen before and advised the crew to switch the signal conditioning equipment (SCE) to auxiliary. That obscure four‑word instruction—“Try SCE to auxiliary”—restored usable telemetry, allowed ground controllers to assess the spacecraft, and enabled the crew to realign systems and continue toward the Moon; the incident also led NASA to tighten launch-weather rules to prevent future close calls.