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#20
by
Hyperion5
on 01 Oct, 2014 02:57
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What performance with 6x Aerojet solids and a 2x RL-10 upper stage? Is a 3x core configuration as with Delta IV-H a viable option? Clustered 5x stages a cost-effective SLS replacement? (not trying to restart old arguments etc - just curious about the performances).
I don't know what the performance is for the first one. Dmitry's looking into it, though not with a dual RL-10 upper stage. The 3X core stage appears to many to be unlikely given the single core's capability. If they were to build a triple-core variant, performance to LEO would be close to the Falcon Heavy's IF you used a more powerful upper stage than the Centaur. Payload to GTO would top 25 mt with enough thrust and Isp on the upper stage. A BE-3U or dual RL-10C engines would probably do the trick.
Assuming you had a 5-core variant, the upper stage would act much more as an in-space stage. Payload would likely be around 4.8-4.9X that of the single core. So figure on somewhere around 95 mt to LEO. It's not the most ideal HLV given its relatively smaller diameter, but it would be more than adequate for most unmanned science missions involving an HLV.
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#21
by
sdsds
on 01 Oct, 2014 03:29
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Heck, since we're making wild guesses about upper stages and such, how about guessing the first payload? My pick is WGS-7. It's likely about 6 t. The prior block II WGS satellites were launched on Delta IV M+ (5,4); this new LV should handle it without need for solids, eh? And since there's likely no urgent need for WGS-7, no one would complain much if the LV were a bit late....
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#22
by
MATTBLAK
on 01 Oct, 2014 04:50
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What performance with 6x Aerojet solids and a 2x RL-10 upper stage? Is a 3x core configuration as with Delta IV-H a viable option? Clustered 5x stages a cost-effective SLS replacement? (not trying to restart old arguments etc - just curious about the performances).
I don't know what the performance is for the first one. Dmitry's looking into it, though not with a dual RL-10 upper stage. The 3X core stage appears to many to be unlikely given the single core's capability. If they were to build a triple-core variant, performance to LEO would be close to the Falcon Heavy's IF you used a more powerful upper stage than the Centaur. Payload to GTO would top 25 mt with enough thrust and Isp on the upper stage. A BE-3U or dual RL-10C engines would probably do the trick.
Assuming you had a 5-core variant, the upper stage would act much more as an in-space stage. Payload would likely be around 4.8-4.9X that of the single core. So figure on somewhere around 95 mt to LEO. It's not the most ideal HLV given its relatively smaller diameter, but it would be more than adequate for most unmanned science missions involving an HLV.
A 5.1 meter diameter stage could probably fit 8x Aerojet solids to it, if they were so inclined to design that feature into it.
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#23
by
sdsds
on 01 Oct, 2014 05:51
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A 5.4 meter diameter stage could probably fit 8x Aerojet solids to it
Yes easily, if they were evenly spaced. But it isn't clear the exhaust from those solids, when ignited on the pad, would be directed down into the flame trench! Here's my picture, showing a 5.1 meter stage (like the Delta IV CBC) with six 1.55 meter Atlas V boosters. Superimposed for comparison is a triplet of Atlas V 3.81 meter CCBs, i.e. the old "Atlas V Heavy" arrangement.
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#24
by
Lobo
on 01 Oct, 2014 19:07
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...
Didn't see that this was a poll. There really isn't no other choices, it will fly with the Centaur stage from the Atlas V on top. Sowers was just being coy. Just think about it. They want/need an RD-180 replacement; Atlas is their cheapest product line; Atlas is the most versatile product line; Atlas legacy is permeating into the Delta product line: what do you think will fly?
I agree that Centaur is most likely, but I still feel that the 5-m DCSS has a lot of good points to it. From what I've heard its PLF is wide enough to accept pretty much any commercial & DoD payload flown so far. Plus any upgraded upper stage ought to be about the same diameter, so you could keep using that PLF. I suppose it might require more expensive changes at first, as you'd have to renovate the pad to accept it. However once renovated it would be easier to transition over to a larger, same diameter new upper stage with two RL-10C engines or one BE-3U engine. I'm also guessing it would be more expensive than the Centaur stage, which along with this being "Atlas heritage", is why we probably won't see the 5-m DCSS up top. Still I think it's not a bad option.
As for heritage, I really don't think it's fair to the "Delta heritage" in this rocket to say it is of "Atlas heritage". At least not of pure Atlas heritage. The core stage is of true "Delta heritage" and the upper stage, at least initially, is of "Atlas heritage". Thus it should be regarded as a child of both rockets. It may be called an Atlas, but in truth its parents will be both the Delta IV & Atlas V. Also, when it comes to "Atlas heritage", the Atlas V today is almost as much of Energia/Zenit heritage (thanks to its RD-180 engine) as it is of Atlas heritage. Its staging is not at all like that of the original Atlas rocket. So I suppose you could call it an Atlas, but it's one that blasts off the pad with a distinctive "Russian accent".
It will be called "Deltlas", as "Atelta" doesnt' really roll off the tounge. Although I suppose it could be an "Alta". "Deltas" sound better I think though.
:-)
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#25
by
Lobo
on 01 Oct, 2014 19:11
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I thought Centaur would fly the RL-10C-1 engine, and Delta the RL-10C-2 engine? Common upper stage engine?
That is what those are.
But isn't the RL-10C-1 a re-worked RL-10A with some simplifications and upgrades, as is the RL-10C-2 an RL-10B? Or are they all re-worked RL-10B's?
The C's aren't brand new engines but reworked existing engines, as I understood.
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#26
by
Jim
on 01 Oct, 2014 19:46
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All reworked RL-10B's
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#27
by
Targeteer
on 01 Oct, 2014 22:52
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The Atlas doesn't/can't use the extended nozzle used on the Delta RL-10 because there isn't room. Will the redesign of Atlas for the new engine allow/make sense to permit the larger nozzle and it's greater performance to be utilized?
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#28
by
Lobo
on 01 Oct, 2014 23:18
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All reworked RL-10B's
Ahhh...ok, thanks.
So will the RL-10C-1 be reworked to mate with current Centaur plumbing? Or will Centaur be changed to accomodate an RL-10B/DCSS type plumbing/mounting?
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#29
by
Lobo
on 01 Oct, 2014 23:20
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The Atlas doesn't/can't use the extended nozzle used on the Delta RL-10 because there isn't room. Will the redesign of Atlas for the new engine allow/make sense to permit the larger nozzle and it's greater performance to be utilized?
With a wider core needing a new interstage anyway, one would assume it could be made to accomodate the nozzle extension, and thus benefit from RL-10B's additional ISP.
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#30
by
kevin-rf
on 02 Oct, 2014 11:53
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The Atlas doesn't/can't use the extended nozzle used on the Delta RL-10 because there isn't room. Will the redesign of Atlas for the new engine allow/make sense to permit the larger nozzle and it's greater performance to be utilized?
I would think they would tackle that problem when they redesign the upper stage.
Centaur is 3 meters (10 feet) in diameter, while the DCSS is 4 meters (13 feet) or 5 meters (16 feet) in diameter. The DCSS RL-10B-2 with the extension as listed is 2.1 meters (7 foot) in diameter. It will be a tight fit until they come out with a wider (ACES) Centaur.
If they use the RL-10 in the upper stage redesign (ACES?), that would be the time to look at it.
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#31
by
baldusi
on 02 Oct, 2014 13:33
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From what I remember from the ULA papers, ACES was supposed to be 4.6m wide, or exactly enough to fit within a 5m fairing. Would they still offer the 4m option, or would they do like SpaceX and offer only 5m fairing with enclosed ACES?
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#32
by
Steven Pietrobon
on 04 Oct, 2014 03:43
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I went with the Delta-IV 4 m upper stage, as the simulations showed it had the greatest GTO performance. However, it seems that only one other person agrees with this! :-)
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#33
by
Ronsmytheiii
on 04 Oct, 2014 13:57
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So will this new LV necessarily use Atlas pads? If they want to use a heavy configuration than SLC-3E really wont work at Vandenberg, would need to use SLC-6. Plus if they are going to use Delta IV core tooling for the core it might make sense to use the existing Delta IV processing infrastructure at VAFB/CCAFS. The only issue that I could see with that would be Centaur integration in the horizontal configuration, but I am sure that it could be integrated vertically using the Delta IV crane since they already do that for payloads.
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#34
by
Hyperion5
on 05 Oct, 2014 01:40
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I went with the Delta-IV 4 m upper stage, as the simulations showed it had the greatest GTO performance. However, it seems that only one other person agrees with this! :-)
To be fair, I think a lot of people are factoring in Jim's statements about the Centaur stage being the most likely rather than pure performance. Myself? I felt that the ability to go to a single diameter would be very beneficial for keeping down build costs. I could be wrong however about the CBC & 5-meter DCSS being the same diameter though. The sources I can find note a .1 meter difference, which if true is really sad. In any case, it would allow you to trim down to a single PLF size, which shouldn't hurt efforts to even the playing field.
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#35
by
Jim
on 05 Oct, 2014 17:13
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To be fair, I think a lot of people are factoring in Jim's statements about the Centaur stage being the most likely rather than pure performance. Myself? I felt that the ability to go to a single diameter would be very beneficial for keeping down build costs. I could be wrong however about the CBC & 5-meter DCSS being the same diameter though. The sources I can find note a .1 meter difference, which if true is really sad. In any case, it would allow you to trim down to a single PLF size, which shouldn't hurt even the playing field.
They aren't building a new vehicle, just a new stage.
The 5m DCSS does not use any of the same tankage as the core.
The Atlas 5 m fairing is actually 5.2 and that has more usage.
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#36
by
Hyperion5
on 05 Oct, 2014 18:39
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To be fair, I think a lot of people are factoring in Jim's statements about the Centaur stage being the most likely rather than pure performance. Myself? I felt that the ability to go to a single diameter would be very beneficial for keeping down build costs. I could be wrong however about the CBC & 5-meter DCSS being the same diameter though. The sources I can find note a .1 meter difference, which if true is really sad. In any case, it would allow you to trim down to a single PLF size, which shouldn't hurt even the playing field.
They aren't building a new vehicle, just a new stage.
The 5m DCSS does not use any of the same tankage as the core.
The Atlas 5 m fairing is actually 5.2 and that has more usage.
Well I guess I should have expected nothing less from ULA in the larger DCSS not using the same tankage as the CBC. It's no wonder the Delta IV is so expensive given lack of commonality like that. As for new stage vs new vehicle, you can make arguments both ways. Going by that argument then the Atlas V was not a "new vehicle". Not everyone would agree with that assessment, particularly when there are new avionics involved.
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#37
by
Jim
on 05 Oct, 2014 18:59
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1. Well I guess I should have expected nothing less from ULA in the larger DCSS not using the same tankage as the CBC. It's no wonder the Delta IV is so expensive given lack of commonality like that.
2.Going by that argument then the Atlas V was not a "new vehicle". Not everyone would agree with that assessment, particularly when there are new avionics involved.
1. Unwarranted snark. ULA had nothing to do with the design of the DIV, it was Boeing. Also, What were you doing in the mid 90's? Where designing launch vehicles then or even now? Show me your resume on how many systems that you have designed and fielded in the last 15 years, much less cost effective ones.
You have no insight into the design trades involved. They wanted "flatter" bulkheads to reduce stage length. Boeing tried to use CAIV in the design.
2. The Atlas V used the same avionics as the Atlas II. The upgrade was cut in later.
The "common avionics" will fly on Delta IV and Atlas V long before this stage flies.
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#38
by
Lars-J
on 05 Oct, 2014 19:44
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Unwarranted snark. ULA had nothing to do with the design of the DIV, it was Boeing. Also, What were you doing in the mid 90's? Where designing launch vehicles then or even now? Show me your resume on how many systems that you have designed and fielded in the last 15 years, much less cost effective ones.
Oh, so that's how it is now? We can't question launch vehicle design decisions without having design and flown our own? Geez, welcome to the Internet. You know you have a weak argument if you have to fall back on that.
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#39
by
Jim
on 05 Oct, 2014 20:23
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Oh, so that's how it is now? We can't question launch vehicle design decisions without having design and flown our own? Geez, welcome to the Internet. You know you have a weak argument if you have to fall back on that.
Always been that way, even applies to sports and other endeavors. Questioning is one thing, making statements and conclusions is another. It helps to know what you talking about and back it up when coming to making conclusions.