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Author
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Topic: Apollo Service Module RCS quads
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Terry
Member Posts: 27
From: UK
Registered: Mar 2008
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posted 03-19-2008 01:12 PM
  
I find it amazing that the Apollo Service Module RCS quads are totally unprotected during launch. Particularly in respect to the forward facing thruster expansion nozzles. I'm guessing that they survive the aerodynamics of launch through the air flow being deflected by the Command Module's Boost Protective Cover. Does that sound reasonable?I did post this question to NASA a few years back and received a confirmation that they would get back to me - unfortunately they never did. Terry |
E2M Lem Man
Member Posts: 846
From: Los Angeles CA. USA
Registered: Jan 2005
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posted 03-19-2008 02:34 PM
There were covers over the RCS nozzles during ascent. These might have stayed on until the RCS was first used and blown off.J.M. Busby |
Terry
Member Posts: 27
From: UK
Registered: Mar 2008
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posted 03-19-2008 02:51 PM
I would have thought that there were too, but there is certainly no visual evidence from any launch pictures I've seen!Here's a hi-res image of the Apollo 11 launch from a tower camera and all the nozzles look completely bare. Terry
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LCDR Scott Schneeweis
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posted 03-19-2008 05:05 PM
No shrouds needed... Boilerplate launches included sensors (vibration and thermal transducers) on the SM RCS to measure impact of launch on the RCS engines through boost phase... instrumentation showed RCS nozzle design (the R-4D's are comprised of ribbed columbium titanium skirts) as well as their placement on the CSM were sufficient to mitigate aerodynamic loads on the quads.------------------
Scott Schneeweis
http://www.SPACEAHOLIC.com/ |
Terry
Member Posts: 27
From: UK
Registered: Mar 2008
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posted 03-19-2008 06:57 PM
Thanks guys for the replies. That one had been bugging me for ages!Terry |
golddog
Member Posts: 210
From: australia
Registered: Feb 2008
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posted 03-21-2008 03:50 AM
As a side note, in the Apollo 12 crew technical debrief, Pete Conrad is recorded as having been concerned the evening before the launch that the upwards firing thrusters might get filled with rain water after plans to "roll back" the white room whilst the rain was still heavy. He indicates that after discussion "everybody concluded that this was no problem". |
FordPrefect
Member Posts: 26
From: Karlsruhe, Germany
Registered: Apr 2005
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posted 03-21-2008 05:51 AM
Interestingly enough, the RCS openings on the Shuttle are indeed covered during the complete pre-launch phase. Probably required since it is a different system? |
E2M Lem Man
Member Posts: 846
From: Los Angeles CA. USA
Registered: Jan 2005
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posted 03-21-2008 01:43 PM
Let me clarify a few things - first, there are covers on the Apollo RCS nozzles, but they are removed before launch. Second - there are fabric covers on the shuttle orbiters RCS and these are burned away or blown away during the ascent phase. If you have ever visited the pad after launch you will find these cloths all over the area (but mostly stuck in the fence on the sea side of the pad). J.M. Busby |
LCDR Scott Schneeweis
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posted 03-21-2008 06:26 PM
The Shuttle forward RCS have Tyvek ring covers that are designed to release after tower clear and are functional on the pad only to prevent encroachment of rain into the thrusters. |
Terry
Member Posts: 27
From: UK
Registered: Mar 2008
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posted 03-22-2008 08:04 PM
You can see the Space Shuttle OMS pod thruster covers being blown away at the moment of the SSME ignition on the pad.There appears to be some sort of diaphragm covering each of them which perforates. Terry |
randy
Member Posts: 2231
From: West Jordan, Utah USA
Registered: Dec 1999
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posted 03-27-2008 04:22 PM
I just purchased a copy of the book "Space- the Ultimate Frontier". On page 10 there is a detailed photo of Apollo 11 from midway up the 3rd stage to the Q-ball on the LES, and there are definitely clear plastic bag like covers on all RCS thrusters.Randy |
Terry
Member Posts: 27
From: UK
Registered: Mar 2008
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posted 03-28-2008 10:48 AM
Hi Randy,The question however is - are these covers in position during launch? I'm aware that there exist a large number of covers and protective devices all over the Apollo-Saturn assembly, although almost of these are removed prior to flight. Terry |
golddog
Member Posts: 210
From: australia
Registered: Feb 2008
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posted 03-28-2008 06:28 PM
The photograph referred to was likely taken from the mobile service gantry and shows the CSM etc in a configuration well before launch. I believe the the comments from CDR of Apollo 12 during the post flight de briefing, as well as the comments from LCDR Scott Schneeweis above would tend to lend credence to the fact that all covers on RCS quads were removed before flight. |
nasamad
Member Posts: 2141
From: Essex, UK
Registered: Jul 2001
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posted 03-28-2008 07:35 PM
Randy, I'm guessing the pictures you refer to are probably similar to these: ...which do both show some kind of plastic bag covering on the RCS engines.Terry, judging by this image the plastic covers weren't in place during the launch phase of the mission. Adam |
golddog
Member Posts: 210
From: australia
Registered: Feb 2008
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posted 03-28-2008 07:57 PM
As indicated in my previous post, the first two photos clearly depict the mobile service gantry in place, and thus are clearly taken well before launch. The launch photo clearly shows all covers removed. |
nasamad
Member Posts: 2141
From: Essex, UK
Registered: Jul 2001
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posted 03-29-2008 05:24 AM
Strange that the Block 2 spacecraft had what appears to be plastic bags covering the thrusters when going by Lot 95 in the upcoming Swann Auction, Block 1 spacecraft had purpose built covers.Adam |
randy
Member Posts: 2231
From: West Jordan, Utah USA
Registered: Dec 1999
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posted 03-29-2008 10:10 AM
Yes Adam, the picture I'm referring to is similar to those in your reply.Randy |
LCDR Scott Schneeweis
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posted 03-29-2008 11:09 AM
quote:
Originally posted by nasamad:
Strange that the Block 2 spacecraft had what appears to be plastic bags covering the thrusters when going by Lot 95 in the upcoming Swann Auction, Block 1 spacecraft had purpose built covers.
They are transport covers provided with every Marquardt RCS engine delivered to North American and similar to the upgraded covers in use on the Block II J missions as shown here (and removed before flight). |
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