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Author Topic: Why was Apollo 12 not destroyed by lightning?  (Read 4357 times)

Offline Eric A. Taylor

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Why was Apollo 12 not destroyed by lightning?
« on: 14/06/2009 12:30:02 »
Eric Taylor  asked the Naked Scientists:
   
A few seconds after it launched in November 1969 the Apollo 12 rocket was struck by lightning. The bolt hit the rocket then travelled down to the launch pad.

All that happened was the computer was knocked off line. Al Bean simply reset it then they carried on to a highly successful moon landing.

My question: Why were they not blown to bits?
 
Eric in Tualatin, Or USA (Near Portland)

What do you think?


 

Offline Vern

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Why was Apollo 12 not destroyed by lightning?
« Reply #1 on: 14/06/2009 13:06:36 »
Lightning strikes to aircraft are common. The conducting skin usually carries the current around the outside with little damage. I suspect that the same happened with Apollo 12. The damage was limited to that produced by the inducted currents.
 

Offline Eric A. Taylor

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Why was Apollo 12 not destroyed by lightning?
« Reply #2 on: 21/10/2009 07:46:48 »
I know this. My father was a flight instructor and I grew up flying in Cessna type planes. Aircraft are not normally grounded to the Earth when struck but the Apollo 12 Saturn 5 was grounded to the launch pad via it's ionized smoke trail.
 

Offline Vern

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Why was Apollo 12 not destroyed by lightning?
« Reply #3 on: 21/10/2009 12:24:53 »
I suspect that the grounding effect helped induce the lightning strike, but also helped direct the current around the craft.
 

Offline Eric A. Taylor

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Why was Apollo 12 not destroyed by lightning?
« Reply #4 on: 22/10/2009 12:46:49 »
You're probably right. Wish I could ask Al Bean myself. He was the only guy on the rocket who knew what was meant when the controllers told them "set SEA(?) to aux". I know the safest place to be in a lightning storm is inside a car not touching the body of the car. The body of the car acts as a Faraday(?) cage and diverts the charge away.
 

Offline Eric A. Taylor

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Why was Apollo 12 not destroyed by lightning?
« Reply #5 on: 30/10/2009 09:59:40 »
Eric, first of all, regarding your question about why Apollo 12 wasn’t “blown to bits”, you need to ask yourself why they would be “blown to bits”.  That is, Eric, come up with a scenario.  (Hint: The Apollo 12 crew was safer in regards to being “blown to bits” than folks in airplanes, and I’ll bet you can’t create a scenario.) [/size]

http://en.wikipedia.org/wiki/John_Aaron
[/quote]

Please pay attention to my qualifier. Bean was the only man "on the rocket"

  Of course the controllers were the brains of the mission. There is so much going on that it's impossible for 3 people to keep track of all the critical systems. The controllers were intensely trained on their own bit of the mission. Also John Aaron played a critical role in the rescue of Apollo 13

  As to a scenario that could blow them to bits? How about severe "pogo" in an engine. This had been a problem in several Saturn 5 flights and had not been completely cured by Apollo 12. The flame inside the engine becomes unstable and shock waves form. These shock waves bounce around inside the engine bell and will tear the engine apart, which will lead to the "bits" thing. Or if the lightning had torn even a tiny hole in the side of the rocket....or the rocket hit's a bad sheer, or there is a complete system failure that leads to a shutdown less than 10 seconds after lift off...or a navigation error causes the rocket to collide with the launch tower.....There  are literally thousands of things that could have gone wrong leading to a "bad day". If you're looking for safety riding chemical rockets is NOT something you should do. Stick with the airlines. The food sucks and airport security sucks but you're far better off. Even with sleepy pilots.
 

Offline graham.d

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Why was Apollo 12 not destroyed by lightning?
« Reply #6 on: 30/10/2009 12:19:03 »
The first passenger aircraft I ever flew in was around 1972. It was a JAL flight from London to Tokyo via Moscow (a DC8). As it took off from Heathrow and got to about 5000 feet there was a loud bang and flash. The cabin lights went out for a few seconds and the engines powered down then ramped up again over about a 5 second period. There was a large black mark on the wing! The pilot said we had been "stluck by rightning". He said it sometimes happens and uttered some reassurances. It flew on without any further mishap and very good it was too. Those were the days when comfort and service mattered.
 

Offline Graeme Cooper

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Why was Apollo 12 not destroyed by lightning?
« Reply #7 on: 20/02/2010 22:18:21 »
Hi, in 1999 I celebrated my 30th Birthday by having a trial flight in a glider. The glider was famously destroyed by a very powerfull lightning strike :o, see my "scrap book" of the days events by clicking on this link:- newbielink:http://sites.google.com/site/thebig40reachfortheskiesagain/ [nonactive]
The attachment on that page is my scrapbook with photos of the wreakage etc, there are also radio and tv interviews.
Just thought you may be interested.
Regards
Graeme Cooper
 

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Why was Apollo 12 not destroyed by lightning?
« Reply #7 on: 20/02/2010 22:18:21 »

 

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