A wiring fault with a long paper trail.
The review board traced the explosion to changes made years earlier. In 1965 the allowed voltage for the tank heaters was raised from 28 to 65 volts, but the thermostatic switches were not upgraded. During a pad test the heaters ran for hours, reached about 1,000 °F and damaged the Teflon insulation on the wires. In flight, a routine stir of the tank set off the fire. [1]
Telemetry, voice loops and the crew’s photographs of the damaged service module all match. NASA redesigned the tanks, and Apollo 14 did not fly until January 1971. [1][2]
Staging a crisis would have meant faking an engineering failure and then fixing a problem that did not exist. The record shows the opposite: an embarrassing design flaw that NASA documented in public. In April 2026 the Artemis II crew finally broke the distance record that Apollo 13 set by accident. [3]
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