The Apollo 13 accident:
Launch: Saturday, April 11, 1970 at 13:13 CST.
At 13:18:5, 5.5 minutes after takeoff - vibration felt. This was the first sign of trouble.
At 21:08 hours on April 13, 55 hours 55 minutes into the mission, tank No. 2 blew up.
The cause of the accident: The voltage of the heaters in the oxygen tanks was 65 volts DC. The thermostatically-controlled switches on these heaters were suitable for 28 volts.
On March 27, two weeks before launch, #2 tank did not empty properly, and the test director decided to "boil off" the remaining oxygen in # 2 by using the electrical heater within the tank. The technique took eight hours of 65-volt DC
power from the ground-support equipment to dissipate the oxygen.

"This subjected the wiring near the heaters to very high temperatures (1000 F), which severely degraded the teflon insulation."

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Above is a summary of what happened. At another site here on Answerpool, the accident is mentioned in a discussion of luck and superstition. Is the whole affair mysteriously mixed up with the fact that launch time on April 11 was 13 hours 13 minutes, and that the accident itself occurred on April 13th?

I would say the accident 'happened' at the time the voltage was upgraded to 65 volts, but the switches were still only good for 28 volts. This was before March 27. Then on March 27, the tank which later blew up was subjected to 8 hours of heating, which fused the switches.

Just wanted to know what you guys think.

[This message was edited by babthrower on 08-13-02 at 08:44 PM.]

If you dig deep enough, you can find apparently "remarkable" coincidences just about anywhere. In reality they are meaningless and mundane, but we humans are consummate pattern-seekers. Evolution has primed our brains to make something of nothing.

Here are a couple of links for further investigation of this "phenomenon" :

http://skepdic.com/lawofnumbers.html

http://www.csicop.org/si/9809/coincidence.html

By the way, I saw a documentary on Apollo 13 that confirmed the voltage mismatch as the underlying cause of the disaster. It seems that there was poor communication between two different government contractors when the voltage standard got changed. Now that I believe!