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Author
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Topic: Apollo 12: launch scrub and flight rules
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WAWalsh
Member Posts: 809
From: Cortlandt Manor, NY
Registered: May 2000
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posted 10-15-2007 09:46 AM
   
What were the guidelines or mission rules for an Apollo launch in adverse weather conditions? It seems that the launch of Apollo 7 was inconsistent with guidelines (or at least Schirra's understanding of them). I was speaking to an old JSC hand last week who said that the decision at the top had been to scrub the launch of Apollo 12 , and that the individual who called off the launch was very surprised an hour later, having left the office, to learn that the launch had occurred. Just wondering if this is misrecalled lore, or whether there was some disagreement that day; as well as what the actual launch rules were. |
mjanovec
Member Posts: 3811
From: Midwest, USA
Registered: Jul 2005
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posted 10-15-2007 10:03 AM
I don't have the answer to your question, but have always wondered how much the presence of the President at that launch played into the decision to launch on a less-than-ideal day. |
Tom
Member Posts: 1610
From: New York
Registered: Nov 2000
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posted 10-15-2007 04:11 PM
I think lately, who was attending the launch had no affect on calling a scrub. I believe within recent history, shuttle launches were postponed with a Vice President in attendance and in another launch attempt, a First Lady. |
mjanovec
Member Posts: 3811
From: Midwest, USA
Registered: Jul 2005
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posted 10-15-2007 04:20 PM
quote:
Originally posted by Tom:
I think lately, who was attending the launch had no affect on calling a scrub.
Sorry, I should have been clearer with my post. I was referring to the Apollo 12 launch, not more recent launches. |
Whizzospace
Member Posts: 110
From: San Antonio, TX
Registered: Jan 2006
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posted 10-16-2007 10:57 PM
Mission Rule 1-404 dealt with flying in stormy conditions. "The vehicle will not be launched when its flight path will carry it through a cumulonimbus (thunderstorm) cloud formation."But I'd wager the waiver that took place was mostly due to the President being in attendance. John W |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 10-16-2007 11:05 PM
I seem to recall though that although the cloud A12 travelled through was classified as a cumulus cloud, it was not considered cumulonimbus (i.e. not a thunderstorm). So it was a bit of a shock when the Saturn V going through it produced a couple lightning bolts. Needless to say, they knew better after that as there were nearby rain producing clouds that day. Ever since, rockets don't fly from KSC when there are rain clouds nearby (let alone in the flight path).If I recall my basic weather training from flight school, cumulonimbus clouds are indeed thunderstorm clouds, but not all rain producing clouds are classified as such. Not even planes are safe to fly through cumulonimbus clouds due to the extreme windshears that can happen in them due to the updrafts and downdrafts (which is what produces the rain in the first place). Then there is also the risk of hitting hail high up in the cloud as well since the extreme updrafts of a thunderstorm can cause water droplets to freeze into hail. Often the hail can thaw back into rain before it hits the ground, but if a plane hits it before it thaws, it can be messy. Rain can be produced in other clouds and the ones experienced over the cape that day tend to be more associated with stable air as opposed to the unstable air that can form thunderstorms. So lightning wasn't really the concern until a certain Saturn V passing through a cloud with a slightly excited electric charge produced a couple bolts. |
art540
Member Posts: 432
From: Orange, California USA
Registered: Sep 2006
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posted 10-16-2007 11:48 PM
Maybe KSC learned a lesson in 1969 but a few miles down the coast at CCAFS on March 26, 1987 Atlas-Centaur 67 was launched in marginal weather conditions and was struck by lightning. The result was a corrupted input to the guidance system which commanded a hard yaw that caused a breakup and total loss of mission. A real shocker to me when I heard about that event. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 10-17-2007 10:51 AM
I remember that launch a little bit. Any idea what the specific weather conditions were that day?I know not long after that NASA, NOAA and one of the universities down there began doing research into lightning production by sending up small rockets (essentially model rockets on steriods) trailing tiny wires behind them in order to trigger a lightning strike down the wire into a special bucket to collect data on what lightning does. As I recall from the articles I read on it, the two reasons cited for the research were Apollo 12 and the Atlas Centaur failure. |
art540
Member Posts: 432
From: Orange, California USA
Registered: Sep 2006
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posted 10-17-2007 11:33 AM
I will let you know if I come across the info. From the video there was some rain and low clouds at LC-36. It occurred at about 50+ seconds and the payload was a Navy Fleet SatCom. |
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