Why did the oxygen tank blow up on Apollo 13?

Answer 1

Cause of explosion

A short circuit occurred in the electrical system when the oxygen tanks were stirred. This caused oxidation and pressure loss to occur in one tank, and then the other which critically disabled the craft and aborted the mission.

The cause of the shorting was later thought to be from a combination of switch design and pre-launch detanking procedures where a switch welded shut, although this was unknown at the time. Normally this switch would open when the temperature rose and turn the heater off. Prior to this, there was a redesign of the voltage system and all components of the tanks were upgraded to the new voltage except the heater thermostat switches. This incompatibility allowed the temperature to rise during testing and to damage the Teflon-coated wiring.

Later, during the mission when the tank was stirred, the exposed wires shorted and the Teflon caught fire. In the pure oxygen environment, the fire was intense, and the resultant heat caused the tank to rupture and also damage the adjacent tank. One cover on the service module was blown off, which later caused Lovell to exclaim when he saw it as it was jettisoned " There's one whole side of that spacecraft missing!" Because the service module burnt up in the earth's atmosphere, as was normal procedure, the findings were made from an investigation into pre-launch procedures and reconstructions of the likely cause of events. The above conditions were simulated in a hangar, and another explosion occurred.