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#40
by
Mark Dave
on 10 Jan, 2012 00:32
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Are there any close ups of the strain gauge straps that are on the SRBs? I notice in some photos there is a sort of sign or logo above the ends of each strap. What does it say?
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#41
by
JayP
on 10 Jan, 2012 01:20
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Are there any close ups of the strain gauge straps that are on the SRBs? I notice in some photos there is a sort of sign or logo above the ends of each strap. What does it say?
Here is one of the booster being towed in. If you zoom in you can see that the label reads "B06T7007A L.H. / B06T8007A R.H." I assume that refers to the drawing number of the individual installations.
Edit - Here is another photo of 3 of the 4 installations down this side of this booster.
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#42
by
spacecane
on 08 Mar, 2012 05:10
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How do the O-rings manage to actually work? I understand that if you just had a pressurized cylinder filled with air or something that the force on the O-rings creates a seal (like in a plumbing application). What I am having trouble understanding is how the rubber doesn't melt. I assume it doesn't burn because there is no oxygen present at the side that gets hot.
Maybe I'm misunderstanding the joints and hot gasses don't touch the rubber but then in that case why did the pre 51-L design have hot gas blow by (and then failure)?
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#43
by
Jim
on 08 Mar, 2012 13:05
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How do the O-rings manage to actually work? I understand that if you just had a pressurized cylinder filled with air or something that the force on the O-rings creates a seal (like in a plumbing application). What I am having trouble understanding is how the rubber doesn't melt. I assume it doesn't burn because there is no oxygen present at the side that gets hot.
Maybe I'm misunderstanding the joints and hot gasses don't touch the rubber but then in that case why did the pre 51-L design have hot gas blow by (and then failure)?
There was asbestos putty that was to protect the rings, the blow by was from gases penetrating the putty.
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#44
by
zeke01
on 08 Mar, 2012 13:45
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How do the O-rings manage to actually work? I understand that if you just had a pressurized cylinder filled with air or something that the force on the O-rings creates a seal (like in a plumbing application). What I am having trouble understanding is how the rubber doesn't melt. I assume it doesn't burn because there is no oxygen present at the side that gets hot.
Maybe I'm misunderstanding the joints and hot gasses don't touch the rubber but then in that case why did the pre 51-L design have hot gas blow by (and then failure)?
There was asbestos putty that was to protect the rings, the blow by was from gases penetrating the putty.
The putty had channels in them due to a leak check that blew pressurized air between the o-rings during stacking. So when the motor fired, the hot gasses had a direct path to the o-rings. This is described in the Rogers report.
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#45
by
DMeader
on 08 Mar, 2012 14:47
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In the re-designed field joint, the putty has been replaced by a rubber flap (called J-leg) that is sealed by the pressure in the casing. More pressure, better seal.
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#46
by
OV135
on 22 Oct, 2012 13:39
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#47
by
Jim
on 22 Oct, 2012 14:39
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#48
by
JAFO
on 19 Feb, 2013 02:46
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Can someone please explain the difference between the 4 seg STS and 5 seg SLS SRB, please? I've heard it said that production of the 4 seg was no longer possible, trying to figure out what the differences are.
TIA
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#49
by
wkann
on 19 Feb, 2013 03:21
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Can someone please explain the difference between the 4 seg STS and 5 seg SLS SRB, please? I've heard it said that production of the 4 seg was no longer possible, trying to figure out what the differences are.
TIA
I alway thought that a 4 seg vs 5 seg SRB was that the 5 seg SRB could lift more weight to orbit. And of course, it has an extra segment for more propellant.
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#50
by
padrat
on 19 Feb, 2013 03:38
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I believe the grain pattern is different as well.....
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#51
by
Calphor
on 19 Feb, 2013 04:05
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The major difference between the two is the additional segment
(I know that is too obvious) added in the middle. The RSRM consisted of the forward, center forward, center aft and aft segments. The 5 segment consists of a forward, center forward, center center (I'm not making this up...), center aft and aft segments. As padrat mentioned there are design tweaks between the two booster grains. The forward segment on RSRM had 11 fins, where as the 5 seg has 12. The 5 seg has some additional chamfer on the forward portion of the bore of the aft 4 segments. The throat diameter is larger for the 5 seg to keep the chamber pressure within case limits. The ablative materials in the nozzle have been altered to deal with the increased mass flow rates. There has been additional length added to the exit cone to regain some of the expansion ratio lost by increasing the throat diameter.
One of the major reasons that RSRM cannot be produced any longer is that the original shuttle requirements called for using a hydroclave to produce the ablative materials for the nozzle. That piece of equipment was decommissioned at the end of the Shuttle program. Also, some of the tooling and hardware was stored or disposed of at program end. Could ATK make a booster that looks the same and has similar performance to RSRM? Sure, given sufficient time and $, but it probably would not be the same as RSRM because of the above issues.
I could continue on, but at some point I would hit the ugly ITAR restrictions and no one wants to see that happen (especially me!). Suffice it to say that there has been significant updating since the idea (5 segment booster) was first tried back in 2003 (ETM-3).
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#52
by
AnalogMan
on 19 Feb, 2013 11:15
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Can someone please explain the difference between the 4 seg STS and 5 seg SLS SRB, please? I've heard it said that production of the 4 seg was no longer possible, trying to figure out what the differences are.
This is from a 2011 paper which gives some details of differences between Shuttle RSRM and Constellation RSRMV (which will also be used for the first two SLS flights):
Modifications to the RSRM design were made to improve performance (thrust), eliminate hazardous materials and replace obsolete materials. Changes from the RSRM are shown [in diagram below] and included:
(1) increasing the number of center segments from two to three,
(2) increasing the number of propellant fins in the forward segment from 11 to 12,
(3) the addition of forward chamfers on center and aft segments,
(4) lowering the propellant burn rate
(5) modification of the propellant inhibitor heights and thicknesses,
(6) increasing the nozzle throat diameter,
(7) extending the nozzle exit cone,
(8) modifying insulation and liner formulations to eliminate Chrysotile fibers, and
(9) modifying the insulation lay-up to increase thermal protection.Note: ETM-3 is an early version of a 5-segment motor that was test fired in 2003.
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#53
by
OV135
on 23 Feb, 2013 22:06
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#54
by
RyanC
on 06 Mar, 2013 05:24
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What would happen if you scaled down a solid rocket motor in every dimension by say 25% (or 50%), and kept all of the basic ratios intact?
Would it perform mostly the same as it's larger version, but with less thrust? [how much less]?
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#55
by
spacecane
on 06 Mar, 2013 12:32
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Are the RSRMVs used for SLS planned to be recovered/"reused"? I put "reused" in quotes since for Shuttle with all the processing required I think it was more like "recyled".
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#56
by
Jim
on 06 Mar, 2013 13:45
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Are the RSRMVs used for SLS planned to be recovered/"reused"? I put "reused" in quotes since for Shuttle with all the processing required I think it was more like "recyled".
no
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#57
by
brad2007a
on 28 Mar, 2013 00:39
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I have a couple of SRB questions that may have been answered elsewhere, possibly in the Shuttle Q&A sections, but these have become quite large, and exhausting to look through (although very interesting, of course.) So if they have been, please point me to the appropriate sections. Anyway, here goes:
These are about possible SRB "nightmare" scenarios during a Shuttle launch, other than the one that befell Challenger 51L. Thankfully none of these scenarios happened, but the reason I ask these questions is because I've heard or read so many conflicting stories about what would've happened in these cases. I'm no expert, so I thought I'd ask the experts here...
1. One SRB ignites, the other does not: I've heard and read the stories about how, should this have happened, the Shuttle would've "cartwheeled" either into the FSS, or the nearby swamps. True or false?
2. At SRB sep, the bolts on both boosters blow, but on, say, one of the boosters the separation motors fail to ignite: How much danger was there of the SRB falling into the orbiter or ET, or was there enough clearance (given the orbiter and ET's velocity at that point) for it to (barely) miss the vehicle?
3. One or both boosters fail to separate: I understand that there was no way for the Shuttle to make orbit with the dead weight of one or both SRB casings, so it would have been an abort (RTLS or contingency), but what would be the likelihood of successfully flipping the vehicle over (as in an RTLS) with the booster(s) still attached?
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#58
by
Jim
on 28 Mar, 2013 02:56
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1. One SRB ignites, the other does not: I've heard and read the stories about how, should this have happened, the Shuttle would've "cartwheeled" either into the FSS, or the nearby swamps. True or false?
2. At SRB sep, the bolts on both boosters blow, but on, say, one of the boosters the separation motors fail to ignite: How much danger was there of the SRB falling into the orbiter or ET, or was there enough clearance (given the orbiter and ET's velocity at that point) for it to (barely) miss the vehicle?
3. One or both boosters fail to separate: I understand that there was no way for the Shuttle to make orbit with the dead weight of one or both SRB casings, so it would have been an abort (RTLS or contingency), but what would be the likelihood of successfully flipping the vehicle over (as in an RTLS) with the booster(s) still attached?
1. true
2. It likely would be LOC
3. no likelyhood
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#59
by
wolfpack
on 28 Mar, 2013 15:06
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I have a couple of SRB questions that may have been answered elsewhere, possibly in the Shuttle Q&A sections, but these have become quite large, and exhausting to look through (although very interesting, of course.) So if they have been, please point me to the appropriate sections. Anyway, here goes:
These are about possible SRB "nightmare" scenarios during a Shuttle launch, other than the one that befell Challenger 51L. Thankfully none of these scenarios happened, but the reason I ask these questions is because I've heard or read so many conflicting stories about what would've happened in these cases. I'm no expert, so I thought I'd ask the experts here...
1. One SRB ignites, the other does not: I've heard and read the stories about how, should this have happened, the Shuttle would've "cartwheeled" either into the FSS, or the nearby swamps. True or false?
2. At SRB sep, the bolts on both boosters blow, but on, say, one of the boosters the separation motors fail to ignite: How much danger was there of the SRB falling into the orbiter or ET, or was there enough clearance (given the orbiter and ET's velocity at that point) for it to (barely) miss the vehicle?
3. One or both boosters fail to separate: I understand that there was no way for the Shuttle to make orbit with the dead weight of one or both SRB casings, so it would have been an abort (RTLS or contingency), but what would be the likelihood of successfully flipping the vehicle over (as in an RTLS) with the booster(s) still attached?
Of those, 3 was the most likely. PASS had a bug where it was possible for the ARM/FIRE1/FIRE2 commands to the booster separation motors to not occur in the same timeslice (my word for lack of a better term), and the BSMs would have failed to fire. Additionally, PASS would have disconnected power to the PICs in the BSMs before BFS could have been engaged to attempt separation. I believe all of this was demonstrated on the ground. Several missions flew with this anomaly.
(I know that is too obvious) added in the middle. The RSRM consisted of the forward, center forward, center aft and aft segments. The 5 segment consists of a forward, center forward, center center (I'm not making this up...), center aft and aft segments. As padrat mentioned there are design tweaks between the two booster grains. The forward segment on RSRM had 11 fins, where as the 5 seg has 12. The 5 seg has some additional chamfer on the forward portion of the bore of the aft 4 segments. The throat diameter is larger for the 5 seg to keep the chamber pressure within case limits. The ablative materials in the nozzle have been altered to deal with the increased mass flow rates. There has been additional length added to the exit cone to regain some of the expansion ratio lost by increasing the throat diameter.