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Author
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Topic: Mystery component on Apollo-Saturn SLA
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tetrox
Member Posts: 142
From: London England
Registered: Jan 2008
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posted 11-17-2010 11:10 AM
   
Looking through Apollo 7 photographs on the Project Apollo Archive I have noticed what appears to be a small circular window towards the top of two petals on the Spacecraft-Lunar Module Adapter (SLA).There also looks to be some kind of instrument across it which I would like to understand the purpose of. |
PeterO
Member Posts: 470
From: North Carolina
Registered: Mar 2002
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posted 11-17-2010 02:21 PM
It actually appears to be in all four petals.It will be tough to tell if it exists in the SLA panels of subsequent missions, since they were completely jettisoned from the S-IVB, rather than being hinged as on Apollo 7. |
tetrox
Member Posts: 142
From: London England
Registered: Jan 2008
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posted 11-18-2010 11:10 AM
I cannot find the same features on subsequent Saturn V vehicles or later Skylab/ASTP Saturn 1B vehicles. |
SpaceAholic
Member Posts: 5565
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 11-18-2010 11:31 AM
That's a large cavernous (empty) space inside the SLA with 14.7 psi of pressure which needed to be rapidly equalized to vacuum during the ascent (recall that in most subsequent missions including ASTP the SLA had a resident). |
tetrox
Member Posts: 142
From: London England
Registered: Jan 2008
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posted 11-18-2010 12:16 PM
There is no evidence of these on photos from Apollo 8. Also they do not show from what I can see on Apollo 1, prior to the devastating fire or Skylab 2, neither of which carried payloads. |
SpaceAholic
Member Posts: 5565
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 11-19-2010 05:52 AM
There were at least some design changes driven by the requirement to jettison the SLA panels subsequent to Apollo 7, could have been others resulting from SA-205 lessons learned. Another incidental data point - SA-205 employed SLA-5; Apollo 8 through Apollo 17: SLA-11A through SLA-21 respectively. |
PeterO
Member Posts: 470
From: North Carolina
Registered: Mar 2002
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posted 11-19-2010 07:18 AM
I doubt that the Apollo 7 ports are actually open holes. NASA went to great pains to tape and cover all openings on all launch vehicles, due to the Florida climate. The CSM was almost completely shrouded while on the pad.Photos showing the open SLA panels clearly have a rectangular box of some sort positioned over each hole with wiring leading to it. It's more likely that they are clear windows covering whatever sensor, camera or gadget is positioned there. |
SpaceAholic
Member Posts: 5565
From: Sierra Vista, Arizona
Registered: Nov 1999
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posted 11-19-2010 07:41 AM
I think you have nailed it. AS07-03-1539 provides a clearish shot of one of the cameras(?). |
tetrox
Member Posts: 142
From: London England
Registered: Jan 2008
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posted 11-19-2010 09:06 AM
The more I look at these as I describe as portals the more It seems to me that they appear as round windows.I have looked high and low for any description and the only clue I can possibly find is in the Apollo 7 mission report which makes mention of the crew during sextant tracking having difficulties tracking Four lights on the S1VB. Whilst not technically part of the S-IVB (the petals) I wondered if these could be the lights mentioned, maybe similar to aircraft flashing lights and the windows would allow them to be seen no matter the orientation of the S-1VB. I cannot find any mention anywhere regarding cameras on the stage. |
tetrox
Member Posts: 142
From: London England
Registered: Jan 2008
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posted 11-20-2010 06:58 AM
Following on from my post yesterday I found a NASA film (40 Years after Apollo 7 [part 1/2]). About 5 minutes 40 seconds in there is some footage of the SLA/S1VB combination rotating. There seem to be flashes of light coming from the portals on the SLA petals. There is of course the possibility that the light is being reflected off glass from maybe the Earth but a couple of the flashes look to me as though they are being generated from that area albeit somewhat randomly. |
mikej
Member Posts: 483
From: Germantown, WI USA
Registered: Jan 2004
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posted 11-26-2010 04:12 PM
I'd have to agree that the components on Apollo 7 are some sort of lights.The original film is on the Spacecraft Films Apollo 7 disc set (chapter 5 "Rendezvous" of the onboards). The components can be seen flashing at random intervals starting at about 9:50 in the video, and more prominently around 11:35. Some of the flashes could have conceivably been caused by sunlight filtering through from behind, but certainly not all of them. Photo AS07-4-1568 shows one of the lights flashing:  The specific reference from the Apollo 7 Mission Report is on page 6-2: The crew reported that in the dark period at terminal phase initiation the flashing lights on the S-IVB were not visible in either the telescope or front window until the range had decreased to less than 15 miles. There's another mention of this same basic information on p. 6-25.I've got photos of the SPS service connections and corresponding SLA access port on my website. |
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