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Author
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Topic: Apollo 11 launch preparations at the pad
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LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 12-05-2014 12:00 PM
  
On July 5, 1969 when Apollo 11 was on the pad, a large section of the S-IVB third stage had to be re-painted. Did that have anything to do with the CDDT which took place around the same time? |
Ken Havekotte
Member Posts: 2983
From: Merritt Island, Florida, Brevard
Registered: Mar 2001
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posted 12-05-2014 01:38 PM
No, I am sure it had nothing to do with Apollo 11's CDDT that took place on July 2 (the WET portion) and July 3 with the DRY portion of the countdown and checkout tests of AS-506.The paint job on 506's third stage got started two days after completion of the CDDT operations on July 5 that involved a 21x22 foot section of the S-IVB's liquid oxygen tank area. |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 12-05-2014 09:18 PM
I have not seen the photo elsewhere, and the caption does not mention why the stage had to be re-painted: KSC Pad workers remove the paint from the third stage of the Apollo 11 Saturn V in preparation for the repainting of a 21 by 22 foot section of the rocket stage in the vicinity of the liquid hydrogen tank. |
sev8n
Member Posts: 236
From: Dallas TX USA
Registered: Jul 2012
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posted 12-05-2014 10:36 PM
Pardon my ignorance but what is CDDT? |
LM-12
Member Posts: 3324
From: Ontario, Canada
Registered: Oct 2010
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posted 12-05-2014 11:29 PM
CDDT is an acronym for the Countdown Demonstration Test that took place about ten days before launch. It was a launch countdown simulation and practice exercise for the launch team and flight crew. From the Apollo 11 Press Kit: After hypergolic fuels were loaded aboard the space vehicle and the launch vehicle first stage fuel (RP-1) was brought aboard, the final major test of the space vehicle began. This was the countdown demonstration test (CDDT), a dress rehearsal for the final countdown to launch. The CDDT for Apollo 11 was divided into a "wet" and a "dry" portion. During the first, or "wet" portion, the entire countdown, including propellant loading, was carried out down to T-8.9 seconds, the time for ignition sequence start. The astronaut crew did not participate in the wet CDDT.At the completion of the wet CDDT, the cryogenic propellants (liquid oxygen and liquid hydrogen) were off-loaded, and the final portion of the countdown was re-run, this time simulating the fueling and with the prime astronaut crew participating as they will on launch day. |
moorouge
Member Posts: 2458
From: U.K.
Registered: Jul 2009
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posted 12-06-2014 01:46 AM
I wonder if this is linked to the launch day incident with LH on the third stage and the use of some judiciously applied water. |
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