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#3060
by
Ronpur50
on 20 Jan, 2014 21:16
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#3061
by
Mike_B
on 10 Feb, 2014 17:25
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I'm working on a 3D model of the shuttle external tank, and in my research, I discovered the "beanie cap" for gaseous oxygen venting, and a "ground umbilical carrier plate" that vents gaseous hydrogen. But where do you pour the liquid oxygen and liquid hydrogen into the tank?
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#3062
by
AS-503
on 10 Feb, 2014 17:34
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Through the tail service masts, of course
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#3063
by
AS-503
on 10 Feb, 2014 17:36
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#3064
by
Go4TLI
on 10 Feb, 2014 17:49
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It flowed through the orbiter's Main Propulsion System and then into the ET. The cryos entered the orbiter through the T-0 umbilicals located on the aft of the ship as noted above. Left hand side is where LH2 entered, right hand side was LOx
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#3065
by
Jim
on 10 Feb, 2014 18:06
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#3066
by
Mike_B
on 10 Feb, 2014 18:09
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Oh that's interesting! I never knew that the liquids flowed through the engines and then all the way up the pipes on the sides to reach the tanks. Thanks, that really explains it. I guess that has to change for the SLS, since there's no orbiter anymore.
Thanks again,
-Mike
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#3067
by
Go4TLI
on 10 Feb, 2014 18:20
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I guess that has to change for the SLS, since there's no orbiter anymore.
Thanks again,
-Mike
No same concept, slightly different execution style. There will still, and has to be, a main propulsion system. There will be service masts from the pad that interface the MPS through similar umbilicals and fill mehtods (for at least the core stage). Any upper stage would be a same basic method, just higher up.
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#3068
by
Jim
on 10 Feb, 2014 18:36
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Oh that's interesting! I never knew that the liquids flowed through the engines and then all the way up the pipes on the sides to reach the tanks. Thanks, that really explains it. I guess that has to change for the SLS, since there's no orbiter anymore.
That is the standard practice for most if not all launch vehicles. For the first stage, they have masts/umbilicals that interface with the booster propulsion system at the base of the vehicle. Saturn V had 3 TSM's, Delta IV uses 2, Atlas uses 1, Falcon 9 incorporates them into the holddown system. There is no need to go any higher on vehicle. The feed lines from the tanks go into the propellant feed system/manifolds at the base of the vehicle , so just plumb into it for the umbilicals. (the tanks fill from the bottom up, not from a inlet on top. There is no faucet like a bath tub, just the drain and the propellant comes in through the same orifice that it leaves. Hence the term like fill and drain valves)
The hydrogen didn't have to go up. The tank is right there.
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#3069
by
Mike_B
on 10 Feb, 2014 19:02
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(the tanks fill from the bottom up, not from a inlet on top. There is no faucet like a bath tub, just the drain and the propellant comes in through the same orifice that it leaves. Hence the term like fill and drain valves)
That makes sense. Since you fill from the bottom, would you have to overcome the pressure generated by the column of fuel/oxidizer? I'm sure that's a basic physics question, but this is an interesting education today.
Thanks again,
-Mike
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#3070
by
Go4TLI
on 10 Feb, 2014 19:08
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(the tanks fill from the bottom up, not from a inlet on top. There is no faucet like a bath tub, just the drain and the propellant comes in through the same orifice that it leaves. Hence the term like fill and drain valves)
That makes sense. Since you fill from the bottom, would you have to overcome the pressure generated by the column of fuel/oxidizer? I'm sure that's a basic physics question, but this is an interesting education today.
Thanks again,
-Mike
Yes, it's called head pressure. Plus the tank vents are open still so the tank is not pressurized.
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#3071
by
Jim
on 10 Feb, 2014 19:19
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That makes sense. Since you fill from the bottom, would you have to overcome the pressure generated by the column of fuel/oxidizer? I'm sure that's a basic physics question, but this is an interesting education today.
Pressure is only determined by the column height of the fluid and not the area. So filling from the bottom takes less energy than filling from the top. Filling from the top, the column height would be more than filling from the bottom and hence the pressure would be more.
http://faculty.wwu.edu/~vawter/physicsnet/topics/Pressure/HydroStatic.html
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#3072
by
PahTo
on 10 Feb, 2014 19:44
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When I get home, I'll try to post a picture of the interface between the ET and the orbiter (got a great shot of Endeavour's while visiting CSC), but I have a question:
Is the fill/drain line from the MPS in to the ET different than the orifice/17" line that carried the prop from ET to MPS during actual engine firing?
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#3073
by
Go4TLI
on 10 Feb, 2014 19:49
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Is the fill/drain line from the MPS in to the ET different than the orifice/17" line that carried the prop from ET to MPS during actual engine firing?
The fill/drain line was an 8" line that was the interface from the T-0 disconnects into the orbiter MPS and then eventually into the 17" feedlines where they interfaced to the tank.
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#3074
by
muomega0
on 10 Feb, 2014 20:24
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To be complete, how is excess propellant dumped on orbit, though the nozzle and/or the fill and drain valves before the He purge?
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#3075
by
Go4TLI
on 10 Feb, 2014 20:44
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To be complete, how is excess propellant dumped on orbit, though the nozzle and/or the fill and drain valves before the He purge?
To vent and safe the MPS system after ET jettison:
LOX was through the engine bells.
LH2 was through the fill and drain valve and out the T-0 interface.
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#3076
by
PahTo
on 11 Feb, 2014 00:53
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Okay, here are port and starboard sides of the interfaces between Orbiter and ET. You can see why I asked about if the fill/drain was done via the big 17", or the smaller ifc/pipe. I imagine the smaller ones are for pressurizing the LOX and LH2 tanks via the MPS during flight.
I should add the "staining/streaking" aft of the port side (LH2) interface was more pronounced on the TPS than on the starboard side.
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#3077
by
Go4TLI
on 11 Feb, 2014 13:36
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I imagine the smaller ones are for pressurizing the LOX and LH2 tanks via the MPS during flight.
I should add the "staining/streaking" aft of the port side (LH2) interface was more pronounced on the TPS than on the starboard side.
On the LH2 umbilical there was the 17" feedline, a 4" recirculation line and a 2" GH2 line that was used to provide ullage and pressurize the hydrogen tank.
On the LOX umbilical there was the 17" feedline and the 2" GOX line that was used for the same purposes as the GH2 line but for the ox tank.
There was also the electrical interfaces and the ET mount interfaces.
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#3078
by
PahTo
on 11 Feb, 2014 15:27
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Good stuff--thanks Go4TLI.
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#3079
by
mgfitter
on 26 Feb, 2014 16:03
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Reading about Shuttle tanking problems I noticed that the External Tanks could only be cryocycled a maximum of 13 times, with a fill-cycle counting as one and a pressure cycle counting as a second.
Does anyone here (Jim?) know which particular components of the tank were responsible for this limit? Was it the Al-Li tanking, the welds, the valves, vents, baffles, parts of the feedlines, flex-joints or what precise bits were the limiting factor?
-MG.
