Author Topic: Apollo 6 SLA Damage  (Read 11632 times)

Offline Proponent

  • Senior Member
  • *****
  • Posts: 5650
  • Liked: 1174
  • Likes Given: 713
Re: Apollo 6 SLA Damage
« Reply #20 on: 05/25/2012 03:04 am »
And, courtesy of rkoenn, this thread contains a transcript of the meeting during which the decision itself was made.
« Last Edit: 05/25/2012 03:06 am by Proponent »

Offline woods170

  • IRAS fan
  • Senior Member
  • *****
  • Posts: 8835
  • IRAS fan
  • The Netherlands
  • Liked: 5897
  • Likes Given: 1992
Re: Apollo 6 SLA Damage
« Reply #21 on: 06/05/2012 06:06 pm »
From the original request for images of the event.... See below.

Offline ugordan

  • Senior Member
  • *****
  • Posts: 7664
    • My mainly Cassini image gallery
  • Liked: 1885
  • Likes Given: 424
Re: Apollo 6 SLA Damage
« Reply #22 on: 06/05/2012 06:10 pm »
Great quality, thanks. Are those grabs from film footage or stills taken in rapid succession?

Offline woods170

  • IRAS fan
  • Senior Member
  • *****
  • Posts: 8835
  • IRAS fan
  • The Netherlands
  • Liked: 5897
  • Likes Given: 1992
Re: Apollo 6 SLA Damage
« Reply #23 on: 06/05/2012 06:38 pm »
Great quality, thanks. Are those grabs from film footage or stills taken in rapid succession?
Grabs from film footage taken by the long-range tracking camera's.

Offline simonbp

Re: Apollo 6 SLA Damage
« Reply #24 on: 06/05/2012 06:40 pm »
It also shows just how massive the base heating on the S-IC was. That stage must have look quite well roasted by burnout.

Offline Lars_J

  • Senior Member
  • *****
  • Posts: 6161
  • California
  • Liked: 665
  • Likes Given: 195
Re: Apollo 6 SLA Damage
« Reply #25 on: 06/05/2012 06:58 pm »
It also shows just how massive the base heating on the S-IC was. That stage must have look quite well roasted by burnout.

Yes, that looks quite severe. Is this due to the engines, aerodynamics, or propellant?
(The F9, for example, does not appear to have base heating that envelops the whole 1st stage)

Offline ugordan

  • Senior Member
  • *****
  • Posts: 7664
    • My mainly Cassini image gallery
  • Liked: 1885
  • Likes Given: 424
Re: Apollo 6 SLA Damage
« Reply #26 on: 06/05/2012 07:07 pm »
Yes, that looks quite severe. Is this due to the engines, aerodynamics, or propellant?

I'm personally leaning toward the aerodynamics explanation. Perhaps it's a specific combination of Mach number/atmospheric pressure for Saturn's flight profile. Perhaps the tapering down from S-II to S-IVB creates a shockwave with an even lower pressure region below it where exhaust can get trapped.

Quote
(The F9, for example, does not appear to have base heating that envelops the whole 1st stage)

No, but it still seems to get charred somewhat by radiant heat from the plume.

Offline zerm

  • Hypergolic cartoonist
  • Full Member
  • ****
  • Posts: 1316
    • Klyde Morris dot com
  • Liked: 33
  • Likes Given: 11
Re: Apollo 6 SLA Damage
« Reply #27 on: 06/06/2012 01:52 am »
It's caused by back-flow and a pressure dynamic between the exhaust gas and the local ambient airmass. NASA came out with a full study and explination of the issue back in about 1968. (I'll post a page from it as soon as I get the time to pull it from my files) Sooting from the backflow was actually seen on the very first Saturn I vehicles. Most of what you see here is simple sooting rather than actual burning.
« Last Edit: 06/06/2012 02:03 am by zerm »

Offline zerm

  • Hypergolic cartoonist
  • Full Member
  • ****
  • Posts: 1316
    • Klyde Morris dot com
  • Liked: 33
  • Likes Given: 11
Re: Apollo 6 SLA Damage
« Reply #28 on: 06/06/2012 02:02 am »

Offline lalmon

  • Member
  • Posts: 4
  • New England
  • Liked: 0
  • Likes Given: 0
Re: Apollo 6 SLA Damage
« Reply #29 on: 10/21/2018 02:29 am »
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740078908_1974078908.pdf

I realize it's something of a long shot posting in this six-year-old thread, but I've had a devil of a time in the last couple of months attempting to find this document, which is no longer on the NTRS server. The STI Help Desk tells me its title - not mentioned in this thread - is Apollo 6: Abnormal structural performance during launch phase and that it has indeed been taken offline. They "have requested a review from the issuing Center for the documentation needed to distribute this document, although we cannot provide a time frame for when, or if, the document will be made publicly available."

I became interested in this document when I read that, among the long list of anomalies that occurred at the 2:13 mark in Apollo 6, continuity was lost on one of the three Emergency Detection System structural integrity hot wires that ran from the CM to the IU. Had a second wire lost connection - two out of of three in the voting logic - an auto-abort would have been triggered.

Has anyone here kept that document? I would be in your debt if you could share it with me.

Edited to add: I'm also interested to find out if the three color launch photos above come from this report, and if they don't, where do they come from?

I'm going to post this as a separate topic, but I'll mention it here as well: Another document I've been looking for - for years in this case - is the Apollo 9 Technical Crew Debriefing (possible titled just "Apollo 9 Debriefing"). It's referenced in the NASA history Chariots for Apollo, but I've seen neither hide nor hair of it. It's of interest to me because it's the first place that had detailed astronaut evaluations of the performance of the LM and the operation of the LM and CSM together. I'm thinking there are probably some gems in there.
« Last Edit: 10/21/2018 02:32 am by lalmon »

Offline lalmon

  • Member
  • Posts: 4
  • New England
  • Liked: 0
  • Likes Given: 0
Re: Apollo 6 SLA Damage
« Reply #30 on: 10/22/2018 01:28 pm »
Someone kindly sent me a Wayback link to the document linked above. I know you can sometimes find currently missing NTRS documents there, but my own search there a few weeks ago, using both the full file name in the link and just the document ID, had returned no results.

Now I know that the color NASA-S-68 photos that appear above in this topic are not in that document; the fact that they're in color seems to indicate they possibly came from a much later document. Does anyone know where they originated?
« Last Edit: 10/22/2018 01:29 pm by lalmon »

Tags: