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#20
by
Lobo
on 21 May, 2014 19:54
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For the RS25E to work on a Delta IV you would need 2 of them, to get the thrust or you can get off the ground. This solves the roll control issue, but do any of you believe the RS25E will be half the cost of an RS68? And I haven't begun to talk about the costs of a completely new aft structural section and new propellant feedsystem that has to be designed, built, and qualified.
No, I don't think going to two RS-25E's would be feasible, for the reason you mentioned. Going form one single engine to another single engine I think could be done without needing too radical of an MPS redesign, but going one engien to two would.
Myself I was advocating looking at more GEM-60's, rather than switching to Atlas SRB's, for the reasons you mentioned.
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#21
by
TrueGrit
on 21 May, 2014 21:58
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Delta HIF was originally designed to do electrical powerup and testing after stage mate. Concept was to be do all integrated stage and box level testing in the Decatur and HIF prior to roll out. After roll out the only thing was to be done was an umbilical integrety check, and flight computer final alignment and quick sequences. As I said the rate collapsed prior to activation and as such it was never activated, but this would be a way to get ahead.
In the end nearly everything aft of the LH2 tank will be redesigned and requalified for Delta to accomidate the RS25. Just for starters the RS25 gimbals at the pump inlet, while RS68 (like RS27) gimbals aft of the pump inlet. The primary load bearing structure of the vehicle aft section is a box for Delta which picks up the engine upside down piramid thrust frame. This is signficantly different than center load pickup of the RS25, which will impact the entire load pickup structure of the compartment. Additionally the location of the two primary feedlines are different, which will result in a need for a new feedline design (which has its own load pickup structure). And this doesn't mention the secondary equirement and thermal shield closeout which are completely redesigned.
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#22
by
Sotar
on 23 May, 2014 17:38
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This has been a really helpful topic for me. I had been contemplating potential up grades of D4M+ in order to fill the gap that Atlas V currently covers between D4M and D4H. My thoughts were to change out the solids. I refrained from asking about it as I don’t know much about rockets but know enough that they are not Lego’s. Though I agree Lego rockets are a lot of fun.
Per TrueGrit my ideas seem impractical and I can now answer the questions pretty much myself. So thank you.
My 2 ideas
1)Replace the GEM 60s with Castor 120s.
- 120s are fat so maybe hard to fit, need new attachment points, electrical etc. Higher total impulse but shorter burn time, per ATK catalog can be used as strap on boosters.
2) Potential to use the Titan IV RSRM to replace the outer Cores on the DIV-H, I don’t have the knowledge to figure out if these would be a benefit or not.
- Out of production, would require modifications to the core, modifications to transporter, acoustics, etc. Unknown if RS-68A could survive the heat.
Would like to hear your thoughts on these.
Ego sum non a erucae scientiae,
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#23
by
Jim
on 23 May, 2014 18:15
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1)Replace the GEM 60s with Castor 120s.
- 120s are fat so maybe hard to fit, need new attachment points, electrical etc. Higher total impulse but shorter burn time, per ATK catalog can be used as strap on boosters.
2) Potential to use the Titan IV RSRM to replace the outer Cores on the DIV-H, I don’t have the knowledge to figure out if these would be a benefit or not.
1. You nailed most of it. The pad can't take it nor the vehicle
2. They wouldn't be a benefit. The outer cores have more impulse.
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#24
by
Helodriver
on 23 May, 2014 18:56
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Pros:
High payload;segments on hand, possibly shared with SLS; Corporate knowledge is fresh; "Reusable"; simpler man rating; fly from LC-39B on a modified shuttle MLP.
Cons:
High acceleration; payload access; expense; rocketsarenotLEGOs
It would look interesting though. Sort of like the LH2 son of SRB-X
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#25
by
gospacex
on 23 May, 2014 19:00
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I want to rip my eyes out looking at this contraption.
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#26
by
bubbagret
on 23 May, 2014 19:10
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Pros:
High payload;segments on hand, possibly shared with SLS; Corporate knowledge is fresh; "Reusable"; simpler man rating; fly from LC-39B on a modified shuttle MLP.
Cons:
High acceleration; payload access; expense; rocketsarenotLEGOs
It would look interesting though. Sort of like the LH2 son of SRB-X
I think you would have to rename it Titan V... Both look and cost would be similar.
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#27
by
Jim
on 23 May, 2014 19:14
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Not viable. Shuttle SRB's lift from the top. They don't have the structure at the aft (without a major design) to lift from the bottom
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#28
by
Helodriver
on 23 May, 2014 19:24
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Not viable. Shuttle SRB's lift from the top. They don't have the structure at the aft (without a major design) to lift from the bottom
There's a solution for that.
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#29
by
Targeteer
on 23 May, 2014 19:27
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Not viable. Shuttle SRB's lift from the top. They don't have the structure at the aft (without a major design) to lift from the bottom
There's a solution for that.
Classic
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#30
by
russianhalo117
on 23 May, 2014 19:32
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Not viable. Shuttle SRB's lift from the top. They don't have the structure at the aft (without a major design) to lift from the bottom
There's a solution for that.
That will only work if you plan on ramming it into the ground first.
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#31
by
Excession
on 23 May, 2014 20:12
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Not viable. Shuttle SRB's lift from the top. They don't have the structure at the aft (without a major design) to lift from the bottom
There's a solution for that.
That will only work if you plan on ramming it into the ground first.
No no no, launch it upside-down using only the SRBs. Then airstart the core when they burn out and use thrust-vectoring to flip it around in the right direction. It works in kerbal space program!
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#32
by
Will
on 23 May, 2014 20:55
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Seriously, how about a pair of monolithic 100 t solids?
Will
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#33
by
Lobo
on 24 May, 2014 04:38
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Delta HIF was originally designed to do electrical powerup and testing after stage mate. Concept was to be do all integrated stage and box level testing in the Decatur and HIF prior to roll out. After roll out the only thing was to be done was an umbilical integrety check, and flight computer final alignment and quick sequences. As I said the rate collapsed prior to activation and as such it was never activated, but this would be a way to get ahead.
In the end nearly everything aft of the LH2 tank will be redesigned and requalified for Delta to accomidate the RS25. Just for starters the RS25 gimbals at the pump inlet, while RS68 (like RS27) gimbals aft of the pump inlet. The primary load bearing structure of the vehicle aft section is a box for Delta which picks up the engine upside down piramid thrust frame. This is signficantly different than center load pickup of the RS25, which will impact the entire load pickup structure of the compartment. Additionally the location of the two primary feedlines are different, which will result in a need for a new feedline design (which has its own load pickup structure). And this doesn't mention the secondary equirement and thermal shield closeout which are completely redesigned.
TrueGrit, Jim,
Thanks for the info. Learning lots of new things. :-)
Doesn't really sound like there's anything that could really be done to "streamline" the number of Delta cores or really improve it's cost structure much from a hardware standpoint anyway. Can't blame a guy for trying.
By the time you are into it for that, you are about into it for a whole new LV.
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#34
by
Lobo
on 24 May, 2014 04:39
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Pros:
High payload;segments on hand, possibly shared with SLS; Corporate knowledge is fresh; "Reusable"; simpler man rating; fly from LC-39B on a modified shuttle MLP.
Cons:
High acceleration; payload access; expense; rocketsarenotLEGOs
It would look interesting though. Sort of like the LH2 son of SRB-X
You'd probably burn up your RS-68...
Cool graphic though.
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#35
by
Lobo
on 24 May, 2014 04:40
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Since we're looking at upgrading of solids, how about integrating a CBC with a pair of 4 segment SRBs?
Not viable. Shuttle SRB's lift from the top. They don't have the structure at the aft (without a major design) to lift from the bottom
There's a solution for that.
Classic
Heheheheh....nice!
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#36
by
MATTBLAK
on 25 May, 2014 06:04
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So for future Delta IV upgrade options; we're back to talking about aluminium/lithium and composite tanks and structures, upper stage engine upgrades and the future possibility of a regenerative version of the RS-68A? A couple tons mass shaved from the core and upper stages, an MB-60 or RL-60 for the 5 meter upper stage, add 4x GEM-60 solids and a regenerative RS-68 and would we be talking about 20+tons to L.E.O. for a 'single stick' Delta IV? Even more if the propellants are densified with slush-liquid hydrogen? This would give more options to the ULA 'launch fleet of one' if Atlas dies: Single stick Deltas with 2x solids or none, the smaller 4 meter upper stage and only using Delta IV-H when really needed. The D-IV-H with all the upgrades, even without propellant cross feed would be a formidable booster.
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#37
by
TrueGrit
on 27 May, 2014 16:10
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I have confidence the M+6 and M+8 are reasonable updates, and wouldn't be in ULA's published payload guide if it wasn't fairly well understood. It would result in a major structural change to the LH2 tank and aft section, to add new solid attach points, along with bringing the rocket back to the wind tunnel to prove out the loads. But these seem technically reasonable things to accomplish, assuming the other structure can manage the peak loads. Don't be surprised if items like air lighting, i.e. Delta II, and RS68 load relief throttling might be needed to mitigate some of the impacts. This reduces the benifit a bit, but the hinted at impacts (i.e. pad accustics and in-flight loads) could be quite costly to mitigate.
Weight to performance trade on first stages says any major strcutural change difficult to justify. Major material change would require significant costs which would have to have a return in said investment. For example a change in the tank to AL-LI would result in a manfuacturing development program to "tune" the tooling used to cut, bend, and weld the tanks together. And there are technical reasons why cryogenic propellant composite tanks are still a concept and not used in prodruction. The so called techical readiness level was missed badly on X-33 and I seems there han't been much progress on large scale tanks since then.
Slush hydrogen and other desified propellants would introduce a large number of problems. It would add a signficant number of new systems to mantain the propellant at a super dense state for the a multiple hour launch window. Secondly the RS68 has never run with super dense propellant... In my memory no large sale engine has ever been tested with super dense propellants. The test stands used to hot fire the engines would have to be updated, don't think they run that cold, and a certification process would have to be pursued. What seems a "small change" to some would be considered a "major chagne" to many as it would be ground breaking technically... And that always comes with surprises.
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#38
by
MATTBLAK
on 28 May, 2014 06:47
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Then if it's all as hard as you're portraying it to be - probably more than a grain of truth - then upper stage upgrades are about all that's left... And RS-68 improvements.
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#39
by
TrueGrit
on 29 May, 2014 15:28
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I personally think super dense propellants and composite tank structures are "not ready for prime time"... And even if they were would introduce significant enough changes that one would probably want to start with a semi-clean state.
To me the preferred evolutionary routes would be:
- Examine different SRM configurations... 6 & 8 as advertised in the ULA payload users guide
- Replace the current Delta upper stages with Centaur based upper stages (would need two sizes)
- Additional RS68 upgrades including a regen nozzle and pump seal changes to reduce helium consumption
- Cross-feed on the Heavy vehicle
The upper stage change seem much more plausible in the near future with talk of ULA moving to a Common Avionics system for both Delta and Atlas. After which Centaur electronics and flight control will be compatible with the Delta first stage and ground systems. This would seem to have the biggest "bang for your buck".
I've already discussed my belief that the SRM configuration changes seem reasonable. While cross-feed has always been a reasonable option on the Delta IV upgrade list... But has a limited need in the market (Heavy isn't in demand).
Latestly the RS68 upgrades are all known, and some have gone to the point of PDR. They would all seem to be a far less risky approach to the than an entirely new development program. I know the industry is clamoring for the R&D funds, and there is an open disdain for a hydrogen booster. But to me the question is... Is it better to go down the route of a RS68 upgrade for 1/3 the quoted cost of a whole new technology development. If past performance is an indicator of the future... That new technology development will end of being 2x the costs and 4x the schedule of what the Air Force and NASA are saying now. That says one could have an improved RS68 and Delta IV for 1/6th the cost and 4x faster than anything to do with a new technology development. But that ship seems to have sailed...
