NASASpaceFlight.com Forum
Commercial and US Government Launch Vehicles => ULA - Delta, Atlas, Vulcan => Topic started by: Lobo on 05/10/2013 11:58 pm
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For anyone in the know about this, I have some questions about this conceptual plan.
http://i40.tinypic.com/2rzsao7.jpg
It lists some LEO ranges, but does anyone have more specific information about some of these configurations. In particular:
1) Atlas Phase 1: An Atlas V-55x with 5m upper stage? It seems to list the core by itself with a shorty 5m upper stage (I assume about the same volume as current Centaur?) at 9mt to LEO, so pretty much just a replacement for existing Atlas V-401. But what about with all 5 SRB's and the full sized 5m upper stage, as shown in that link? Somewhere between 9 and 39mt obviously, but where exactly? 25mt maybe? And what would be the GTO capability of it?
2) Atlas Phase 2: Single stick with SRB's as shown. How many SRB's would this be in reference to as shown? 5 like the 3.81m core? Or more?
How much capacity to LEO and GTO? Or TLI?
3) Atlas Phase 2: Tri-core Heavy. Lists LEO performance at 75mt. What is it's GTO, GSO, and Escape performance (approximately)?
I've heard these different LV mentioned in several threads in several contexts, as replacement for Delta IV heavy, to LV's for a new manned lunar program. But, as we know with F9 and FH, their LEO and GTO/GSO and escape number are very different. FH should beat D4H in capacity to LEO by a whopping 30mt...but I believe it's about 2mt less to GTO than D4H? So if you need 13mt to GTO, FH probably can't do it without a 3rd stage or something.
I've heard Jim mention that an Atlas Phase 1, single stick, 5 SRB with 5m upper stage could have gotten a fully fueled Orion to LEO without needing Atlas V Heavy or D4H. But what's it's LEO, GTO, GSO, and/or Escape performance?
If ULA were to retire the Delta IV family at some point, could Atlas Phase 1 with 5m upper stage replace D4H's capabilities?
Etc.?
I'd love to know these various performance numbers if anyone has them. I've not been able to find them myself.
THanks.
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Bumping this.
Does anyone have an idea on these specifications?
Or have they not been made public knowledge by ULA?
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Or have they not been made public knowledge by ULA?
Bingo
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Or have they not been made public knowledge by ULA?
Bingo
Fair enough.
Do you have any "rough guestimates" or approximations that could be shared?
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1) Atlas Phase 1: An Atlas V-55x with 5m upper stage? It seems to list the core by itself with a shorty 5m upper stage (I assume about the same volume as current Centaur?) at 9mt to LEO, so pretty much just a replacement for existing Atlas V-401. But what about with all 5 SRB's and the full sized 5m upper stage, as shown in that link? Somewhere between 9 and 39mt obviously, but where exactly? 25mt maybe? And what would be the GTO capability of it?
You can sort of work backwards from the fact it can put a ~25t spacecraft into LEO. Approximately speaking, we're talking around 12t to GTO and around 10t through TLI (very much rough guesses). I'd say the non-truncated Phase 1 would be in the 15-25t IMLEO performance bracket with around 12t to GTO. An Atlas-V-5H4 (the heavy version) would likely approach 35t IMLEO/15t GTO
2) Atlas Phase 2: Single stick with SRB's as shown. How many SRB's would this be in reference to as shown? 5 like the 3.81m core? Or more?
How much capacity to LEO and GTO? Or TLI?
I'd say probably six SRBs as there is a wider core to fit them onto.
At a guess, the performance would be 25t IMLEO for the 501 baseline model and would reach up to about 40t IMLEO for the maximum lift version.
3) Atlas Phase 2: Tri-core Heavy. Lists LEO performance at 75mt. What is it's GTO, GSO, and Escape performance (approximately)?
The key performance indicator of the Phase-II tri-core is that it is in the SLS Block-I performance range: 70t IMLEO and 25t+ through escape - enough to send an Orion to LLO or the EML points in a single launch.
As you can see, there is also a quin-core version that takes the IMLEO performance over 100t. I suspect that with propellent cross-feed and a wide-body upper stage similar to the SLS Block-II but with RL-10 or RL-60 instead, it could match Ares-V's performance metrics: >130t IMLEO and >50t TMI.
I've heard these different LV mentioned in several threads in several contexts, as replacement for Delta IV heavy, to LV's for a new manned lunar program. But, as we know with F9 and FH, their LEO and GTO/GSO and escape number are very different. FH should beat D4H in capacity to LEO by a whopping 30mt...but I believe it's about 2mt less to GTO than D4H? So if you need 13mt to GTO, FH probably can't do it without a 3rd stage or something.
The key here is the upper stage. It is a Centaur-heritage hydrolox with between 1 and 4 RL-10B-2s or RL-10Cs. That means it shares the Delta-IV's virtue of a greater proportion of its IMLEO performance being preserved into higher orbits and even escape payloads.
The upper stages would likely also have some optimisation: 1 x engine for satellites to GTO and interplanetary probes and 4 x engines for cargo to LEO. The 4 x engine model might also be used for large through-escape cargoes, retaining propellent by only using two engines for the escape burn where impulse is more important than total thrust.
If ULA were to retire the Delta IV family at some point, could Atlas Phase 1 with 5m upper stage replace D4H's capabilities?
In a word? Yes. It might be politically iffy, though. Remember that the core uses 2 x RD-180. If PWR can't make a clone, there could be some Congressional complaints about a 'foreign' engine being used.
As Jim says below, no-one outside ULA knows precisely what the performance figures are for the Atlas-V and similar all-EELV upgrade programs. ULA are playing these cards close to their chest for whatever reason. However, from the released information we can make some educated guesses.
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Some of the answers you are looking for are included in this paper from ULA. It doesn't say a lot about Phase 1, but it does give a little information. On page 6 there is a nice figure that shows the various flavors of Phase 2 as well as performance to various orbits.
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While it's nice to see a development path laid out for the growth of the Atlas V, increasing its payload to LEO & beyond, surely, in this day & age, it's even more important to talk about the economics (costs) of building ever-larger rockets.
The price of an Atlas V hasn't been explicitly stated, but anecdotal evidence puts it around 140 to 180 million for an Atlas V 401. At each stage of development, what, approximately, would be the price (or cost) of the upgraded launcher?
Remember, Falcon Heavy (53 metric tonnes to LEO) is supposed to cost no more than 125 million dollars. Building an Atlas V upgrade that matches the payload (more or less) while coming in at two or three (or more) times the cost is a bit of a non-starter.
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You can sort of work backwards from the fact it can put a ~25t spacecraft into LEO. Approximately speaking, we're talking around 12t to GTO and around 10t through TLI (very much rough guesses). I'd say the non-truncated Phase 1 would be in the 15-25t IMLEO performance bracket with around 12t to GTO. An Atlas-V-5H4 (the heavy version) would likely approach 35t IMLEO/15t GTO
That graphic I posted in the original post shows 39mt to LEO for Atlas Phase 1-Heavy, so a bit more than you listed there. So maybe 16 or 17 to GTO?
I'd say probably six SRBs as there is a wider core to fit them onto.
I believe the Atlas V 3.81m core has room to mount more than 5 SRB's, it's just not designed to mount more than that. Jim would probably know why. It might put too much load on the core or something?
http://www.wired.com/images_blogs/photos/uncategorized/2008/07/09/atlas_v_family.png
Looks like there's be physically enough room for another 4-5 SRB's on there. It'd look like a bigger Delta II.
So the 5m Atlas Phase 2 core could physically fit more than that if they wanted to. But the side view graphic doesn't show SRB's all the way around. So probably at least 5 like the Atlas V-551, but I don't know.
Anyone else know how many SRB's an Atlas Phase 2 would mount in ULA's concept?
At a guess, the performance would be 25t IMLEO for the 501 baseline model and would reach up to about 40t IMLEO for the maximum lift version.
Yea, I think that's about what the ESAS report had for it. I think the ESAS report said it was a little too low of performance...but I'm not sure how. And even if so, they could have put a couple of Atlas SRB's on it I'd think.
The key performance indicator of the Phase-II tri-core is that it is in the SLS Block-I performance range: 70t IMLEO and 25t+ through escape - enough to send an Orion to LLO or the EML points in a single launch.
As you can see, there is also a quin-core version that takes the IMLEO performance over 100t. I suspect that with propellent cross-feed and a wide-body upper stage similar to the SLS Block-II but with RL-10 or RL-60 instead, it could match Ares-V's performance metrics: >130t IMLEO and >50t TMI.
They didn't like that in the ESAS report. They said there was no pad that could launch it, and that it had more than two boosters. Not really sure why it couldn't launch from KSC, but I think it was the depth dimension as each booster was at 90 degrees to each other.
But I'd think if NASA wanted it, ULA could have designed the boosters in two pairs on each side, so it'd fit ok at KSC. And I think NASA's aversion to more than two boosters was misplaced. Especially since that LV would be cargo only, with Orion launching on a single stick Atlas Phase 2.
To get over 130mt, I'd think it might need a J2X/J2S engine and a lot more propellant. The SLS core burns almost all the way to orbit, so the upper stage doesn't need to do much ascent. Even with crossfeed, I don't think the central core of Atlas Phase 3a quin-core would burn nearly that long.
So the upper stage would need to do more of the ascent. A Clusters of RL-60's should work too. I don't think RL-10's would do it.
Still, it would have been a much better way to go than Ares 1/5....ahhh...missed opportunities...
In a word? Yes. It might be politically iffy, though. Remember that the core uses 2 x RD-180. If PWR can't make a clone, there could be some Congressional complaints about a 'foreign' engine being used.
As Jim says below, no-one outside ULA knows precisely what the performance figures are for the Atlas-V and similar all-EELV upgrade programs. ULA are playing these cards close to their chest for whatever reason. However, from the released information we can make some educated guesses.
Well, the USAF/DoD seemed to be using the RD-180 just fine for top secret national security payloads, so how much issue would it really be?
and if it was a probablem for NASA's LV to have them, I don't think paying PWR to develop a US version of it would be any more expensive than RS-25E. And it wouldn't be needed up front. They could say the RD-180's were to be used during the early blocks of the program for development, and then switch to a similar US engine later. And maybe that keeps getting put off...
Yea, sounds like ULA is keeping that info. I just thought it might be out there somewhere, I've just been unable to find it.
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While it's nice to see a development path laid out for the growth of the Atlas V, increasing its payload to LEO & beyond, surely, in this day & age, it's even more important to talk about the economics (costs) of building ever-larger rockets.
The price of an Atlas V hasn't been explicitly stated, but anecdotal evidence puts it around 140 to 180 million for an Atlas V 401. At each stage of development, what, approximately, would be the price (or cost) of the upgraded launcher?
Remember, Falcon Heavy (53 metric tonnes to LEO) is supposed to cost no more than 125 million dollars. Building an Atlas V upgrade that matches the payload (more or less) while coming in at two or three (or more) times the cost is a bit of a non-starter.
I think part of that cost is due a few things.
A major one, is I think when the EELV program was conceived, they expected there to be more launches per year between USAF and DoD. After everything, it turns out there's only maybe 6-10 launches per year, and that's split between the two launchers. So there's not much in the way of the economics of scale helping out.
Four pads to maintain instead of just two.
There's a lot of legacy expenses as well, with unions and such.
If NASA were to have used EELV's or EELV derivatives for their launchers, they'd have increased the production rate which should bring the cost down per LV, at least some.
And certainly developing an Atlas Phase 2 or something would have been just a fraction of the cost of Ares 1 and/or Ares V, and have been flying in a few years after getting the contract.
I'm mainly curious as to this in the context of NASA using them as a foundation of their LV system and working in conjunction with USAF/DoD, moreso than developing them to be compeative in the more cost-sensitive commerical market.
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Does anyone know about what the performance would be of an Atlas V-551/552 Phase 1 with 5m upper stage?
The ULA Atlas growth chart has a LEO range of 9-39mt, but that includes a single stick with no SRB's, up to a tri-core heavy. So it's hard to say what Phase 1 would do with 5 SRB's.
The document Calphor posted above appears to show an Atlas 55x-Phase 1 at 25mt to LEO. Is that about accurate?
If ULA were given the latitude at some point by USAF to downselect to just one operational LV, and assuming that would be Atlas, could that version of Atlas adequtely cover the missions that D4H does now?
And if so, what's the mostly likely upper stage they'd do in that case? Adapt the 5m DCSS to an Atlas 55x as it already exists? Or develop a new 5m Centaur or ACES upper stage?
I don't think there's been a payload that's needed more than the standard D4H. The newer version with RS-68A outperforms that, but is there any payload that would need that vs. an Atlas Phase 1 that can do 25mt to LEO, and I assume with a 5m upper stage, very similar GTO payload.
Is that an option for ULA to cover D4H's capability with Atlas without needing a tri-core Atlas? And would it reduce their costs an operating expenses vs. continuing to fly D4H if USAF were to some day stop requiring them to operate both LV's?
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Phase 1 with five SRBs does over 26 tons, maybe about 28, according to the ULA ACES depot paper (they stated that a single core Atlas could get up to 26 tons of propellant to LEO, and that didn't include the extra tanks space so it's almost certainly more). However, that performance would require a 5 meter 4 engine ACES upper stage.
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Phase 1 with five SRBs does over 26 tons, maybe about 28, according to the ULA ACES depot paper (they stated that a single core Atlas could get up to 26 tons of propellant to LEO, and that didn't include the extra tanks space so it's almost certainly more). However, that performance would require a 5 meter 4 engine ACES upper stage.
Cool. Just wondering if that would cover the D4H range or not. And if so, could ULA still cover all government payloads with just Atlas V plus the new upper stage? I didn't know if multple engines would be needed. What if it's going to BLEO? The 5m DCSS only has one engine.
Could an Atlas V mount a 5m DCSS? Or would need a Centaur based upper stage?
I know the common upper stage concepts have all seemed to be Centaur based rather than DCSS based. Just wasn't sure. Using the 5m DCSS seems like it would save development cost if it could be adapted and if it would given desired performance.
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Replace the boosters with the Pyrios booster?
If cheap enough. a one or two engine booster made up of F-1B engines might put a lot of new life in the Atlas V.
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Lots of talk here about building bigger rockets to loft more tonnes to LEO, but when you really look at the EELV record it doesn't show maxed out LEO missions. It mostly shows missions to higher energy orbits with 3 to 7 tonne payloads. Last year's average Atlas 5 payload weighed less than 3.5 tonnes.
- Ed Kyle
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Lots of talk here about building bigger rockets to loft more tonnes to LEO, but when you really look at the EELV record it doesn't show maxed out LEO missions. It mostly shows missions to higher energy orbits with 3 to 7 tonne payloads. Last year's average Atlas 5 payload weighed less than 3.5 tonnes.
- Ed Kyle
Ed,
Yes, understood. D4H has only flown a handful of times during the life of the EELV program. It's not needed often. Which is why I was curious about Atlas options which could still operate as the (from what I understand) the cheaper and more versitile of the two EELV's, yet still cover the occasional USAF/DoD need for D4H's capability.
Jim said on one of the threads that Atlas would likely be the survivor in a downselect. And Atlas Phase 1 seems like it would basically cover D4H's range. So I was just curious about such a scenario. Not to build up Atlas, but just give it enough extra performance to cover D4H so the whole Delta IV line could be retired without any loss of capability to USAF/DoD.
It looks like Atlas Phase 1 with a 5m Centaur derived upper stage could cover D4H's range. What about by adapting the 5m DCSS to fly on it? (which would save development costs vs. a new WBC stage)
Or would they just concede those few D4H payloads to FH, and focus on the other 90+% of the government payload that can fly on Atlas with existing Centaur, and avoid any new development?
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Can somebody who works in the industry advise if it is possible to use longer solids on the Atlas V? Is this feasible, just not possible or has no benefit? I ask because most questions about AV solids and greater lift capacity revolve around adding more solids yet I can't find info on the feasibility of extending them up the side of the first stage.
This assumes longer means more propellant and more lift capacity.
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Longer basically equates to more thrust. Longer may be possible but there maybe infrastructure issues.
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If improving Atlas's performance were desirable for ULA at some point in the future, which way would be the most economical and feasible?
A) Improved SRB's as Vapour mentioned
B) Larger upper stage
C) Tri-core booster.
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Larger upperstage
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Larger upperstage
Interesting. That was my guess, but only a guess.
So what sort of new upper stage would it likely be? I'm assuming they can't or won't just adapt a 5m DCSS to fit on Atlas? Would it be something like ACES? Or more like a scaled up Centaur with larger balloon tanks? Would it use RL-10's or switch to like an RL-60 or something?
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Use of the Delta IV 4m or 5m upper stages as a Centaur replacement on Atlas resulted in the need to add an SRM to nearly every mission due to the heavier dry masses.
http://www.ulalaunch.com/site/docs/publications/ULA-Innovation-March-2010.pdf (page 5)
I think what Jim means is a larger diameter Centaur, something like the Centaur G used on Titan IV or the ACES proposal.
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Larger upperstage
Interesting. That was my guess, but only a guess.
So what sort of new upper stage would it likely be? I'm assuming they can't or won't just adapt a 5m DCSS to fit on Atlas? Would it be something like ACES? Or more like a scaled up Centaur with larger balloon tanks? Would it use RL-10's or switch to like an RL-60 or something?
The ACES plan, or something like it, seems most likely to me. That is essentially a "Fat Centaur" powered by multiple RL10C engines (or equivalent) that starts with 40-ish tonnes of propellant and can grow to 70 tonnes or more. The stage would be designed to serve on Delta 4 as well, creating a true common stage in a move to cut costs.
Looking back at the growth of Atlas Centaur and Thor-Delta over the years shows incremental improvements in lower and upper stages, usually in differential steps. Thus, the next step after "Fat Centaur" is likely improved solid boosters. Eventually a "Fatter Atlas 5" might occur, but not for many years.
- Ed Kyle
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Looking back at the growth of Atlas Centaur and Thor-Delta over the years shows incremental improvements in lower and upper stages, usually in differential steps. Thus, the next step after "Fat Centaur" is likely improved solid boosters. Eventually a "Fatter Atlas 5" might occur, but not for many years.
- Ed Kyle
Not to argue, but:
1. The solid's on Atlas are already quite large. Much larger than the ones on Delta IV. They spent quite a bit of money developing and tailoring them to Atlas.
3. I assume a Fat Atlas requires two RD-180's. Meaning pad changes?
Like you and Jim said, the low hanging fruit is Centaur. There have been several proposals in the past for a Wide Body Centaur / ACES. A larger Centaur will hold more LH/LOX and be able to push more mass to high energy orbits, while a multi RL-10 Centaur would improve the TWR and be able to push more to LEO.
If I remember correctly, the original ACES proposal not only had room for between 1 and 6 RL-10's but variable length LH/LOX tanks. It could be optimized for HEO (1 RL-10, long tank), LEO (Multiple RL-10 reducing gravity losses) and large Heavy Boosters (Long Tank, multiple RL-10's).
I think the next low hanging fruit after a larger tank is an RL-10 replacement. The ACES proposal highlights the need for higher thrust in some applications. ULA has also been making noise about the RL-10 costs. I think if they can get a lower cost RL-10 replacement that has higher thrust. I can not see why they will not move to it before moving to improved solids or Fat Atlas.
The other low hanging fruit is a common Atlas/Delta IV upper stage.
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Larger upperstage
Interesting. That was my guess, but only a guess.
So what sort of new upper stage would it likely be? I'm assuming they can't or won't just adapt a 5m DCSS to fit on Atlas? Would it be something like ACES? Or more like a scaled up Centaur with larger balloon tanks? Would it use RL-10's or switch to like an RL-60 or something?
The ACES plan, or something like it, seems most likely to me. That is essentially a "Fat Centaur" powered by multiple RL10C engines (or equivalent) that starts with 40-ish tonnes of propellant and can grow to 70 tonnes or more. The stage would be designed to serve on Delta 4 as well, creating a true common stage in a move to cut costs.
Looking back at the growth of Atlas Centaur and Thor-Delta over the years shows incremental improvements in lower and upper stages, usually in differential steps. Thus, the next step after "Fat Centaur" is likely improved solid boosters. Eventually a "Fatter Atlas 5" might occur, but not for many years.
- Ed Kyle
Assuming a "Fatter Atlas 5" would be a 5m core with two engines, wouldn't that be more likely to be the next upgrade after Fat Centaur? Given that ULA has the 5m core tooling necessary already? (be different if they didn't). That would do away with the SRB's altogether for most/all launches, seemingly simplifying things.
Or would upgraded SRB's be a cheaper upgrade than a wider core with extra engine?
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Two engines, and you double the cost of the first stage engines. That is not a small chunk of change.
Considering 26 of 46 Atlas launches to date are v401/v501 configurations without solids. Do you need the large boost in performance a fatter Atlas with two RD-280's would provide? Is an extra RD-180 cheaper than a the solids it replaces?
A more capable Centaur (Wide Body/ACES) would reduce the number of solids needed, reducing costs and pushing more missions to the v401/v501 platform. A cheaper better higher thrust RL-10 replacement would have a similar effect.
This is especially true if you can move the v411/v421/v511/v521 missions, 8 to date, to the v401/v501. That would account for 34 of the 46 flown missions.
Again, I will state Lockheed spent a good chunk of change sizing and developing solids so they would have dial a rocket. What would a more powerful solid buy you? Other than a small handful of payloads that fly on the Delta IV heavy, Atlas can currently launch everything. Do you really need bigger solids. ACES only makes sense if it costs less than the Centaur and incremental solids it replaces. Bigger solids will reduce ULA's dial a rocket's flexibility.
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ACES would be a Common Stage. Not only increases base performance, but significantly lowers cost overall. Plus Common Avionics and a lot of work can be done to unify Mission Control, for example.
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ACES would be a Common Stage. Not only increases base performance, but significantly lowers cost overall. Plus Common Avionics and a lot of work can be done to unify Mission Control, for example.
Launch control, there is no mission control ;-)
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Not to argue, but:
1. The solid's on Atlas are already quite large. Much larger than the ones on Delta IV. They spent quite a bit of money developing and tailoring them to Atlas.
True, and I'm sure that ULA wants to fly the existing motors for years. But that doesn't mean that they can't eventually be upgraded - just like Thor-Delta's boosters were incrementally upgraded over four decades. When the Atlas 5 boosters were developed, they were among the world's largest monolithic solid rocket motors (second to Castor 120, I think). They have since been surpassed, by both JAXA's SRB-A and by Vega's P80FW - and even bigger monolithic motors are on the drawing board.
3. I assume a Fat Atlas requires two RD-180's. Meaning pad changes?
I think that the basic platform could still be used, but some mods might be needed. But, again, this particular change wouldn't be needed for many years, or even decades.
- Ed Kyle
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Agreed.
I was mainly wondering if Atlas V could be made to cover D4H's capability if there were reason at some point in the future to for ULA to want to down select to just one LV, without too much change to Atlas. It actually does sound like Atlas 55x with fat Centaur would be pretty close to covering it.
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Out of curiosity, why does the current Centaur on Atlas not use the better performing RL-10B-2? Is it just that the Atlas interstage is too narrow for the RL-10B-2's nozzle extension? I'd always assumed that but, I'm wondering if that's correct, or if there's another reason, like the RL-10B-2 has a different design for the DCSS vs. RL-10A-4-2 for Centaur?
Seems like going to the RL-10B-2 would not only have given more synergy between the two LV's, but give Atlas a bump in performance.
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Maybe because the RL-10B-2 was designed for the Boeing Delta III/IV programs, and Centaur already existed?
What ever happened to ULA modifying some of the excess RL-10B-2 inventory to work on Centaur? At one point ULA had a plan.
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Out of curiosity, why does the current Centaur on Atlas not use the better performing RL-10B-2? Is it just that the Atlas interstage is too narrow for the RL-10B-2's nozzle extension? I'd always assumed that but, I'm wondering if that's correct, or if there's another reason, like the RL-10B-2 has a different design for the DCSS vs. RL-10A-4-2 for Centaur?
Seems like going to the RL-10B-2 would not only have given more synergy between the two LV's, but give Atlas a bump in performance.
Doesn't fit in the Atlas interstage
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Maybe because the RL-10B-2 was designed for the Boeing Delta III/IV programs, and Centaur already existed?
What ever happened to ULA modifying some of the excess RL-10B-2 inventory to work on Centaur? At one point ULA had a plan.
ULA is going to the RL-10C-1 for Atlas and RL-10C-2 for Delta
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Maybe because the RL-10B-2 was designed for the Boeing Delta III/IV programs, and Centaur already existed?
I think the RL-10B-2 flew in 1998 on Delta III, before the RL-10A-4-1 in 2000 and RL-10A-4-2 in 2002. Centaur was flying RL-10A-4 at that time in the "Centaur-T" configuration on Titan IV, and another dual engine version on Atlas II, If I understand the timeline correctly. After that was the current Centaur (Called "Centaur 3" I think?) flying on Atlas III and Atlas V, which changed from the RL-10A-4 to the 4-1 and 4-2.
So time wise, I think it was available to be used on the current Atlas V Centaur, and had more thrust and more ISP. But didn't know if it was a matter if it having different interfaces for the DCSS and couldn't be adapted for Centaur? Or just a matter of lack of width in the Atlas V interstage for that big nozzle extension.
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Out of curiosity, why does the current Centaur on Atlas not use the better performing RL-10B-2? Is it just that the Atlas interstage is too narrow for the RL-10B-2's nozzle extension? I'd always assumed that but, I'm wondering if that's correct, or if there's another reason, like the RL-10B-2 has a different design for the DCSS vs. RL-10A-4-2 for Centaur?
Seems like going to the RL-10B-2 would not only have given more synergy between the two LV's, but give Atlas a bump in performance.
Doesn't fit in the Atlas interstage
Ahhh, ok, thanks for the clarification.
I'm assuming it would have been more costly to have modified the Atlas V interstage area to fit the RL-10B-2, than the performance increase it would have given? So not worth the investment of doing that, so they keep flying the A's?
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I'm assuming it would have been more costly to have modified the Atlas V interstage area to fit the RL-10B-2, than the performance increase it would have given? So not worth the investment of doing that, so they keep flying the A's?
Also different mixture ratio.
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Hi, I've been following the US space industry sine Atlas E days (doesn't mean I know anything) and I seem to recall in the early to mid 2000s that it was stated the Atlas V 551 could actually launch more payload to orbit with the current engine/booster combination but there is a limitation imposed by the vehicle's structure where it just can't handle anything heavier.
Can someone confirm or discount this?
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Hi, I've been following the US space industry sine Atlas E days (doesn't mean I know anything) and I seem to recall in the early to mid 2000s that it was stated the Atlas V 551 could actually launch more payload to orbit with the current engine/booster combination but there is a limitation imposed by the vehicle's structure where it just can't handle anything heavier.
Can someone confirm or discount this?
There is a structural limit for stock Centaurs and it only applies to LEO missions where the capability is high. If Atlas were to do such a mission, different tank skin would be needed and I think the forward adapter would have to be beefedup.
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Hi, I've been following the US space industry sine Atlas E days (doesn't mean I know anything) and I seem to recall in the early to mid 2000s that it was stated the Atlas V 551 could actually launch more payload to orbit with the current engine/booster combination but there is a limitation imposed by the vehicle's structure where it just can't handle anything heavier.
Can someone confirm or discount this?
There is a structural limit for stock Centaurs and it only applies to LEO missions where the capability is high. If Atlas were to do such a mission, different tank skin would be needed and I think the forward adapter would have to be beefedup.
Would a new 5m upper stage be designed from the start for maximum (Atlas-55x) LEO payload mass, just in case it's ever used for that purpose? Or woudl it be made lighter in anticipation it's typical BLEO payloads?
Also, would an Atlas with a 5m upper stage use the Delta IV 5m PLF, and just have it sit on top as it does on Delta? Or would it use a new Atlas 5.1m PLF and encapsulate the upper stage as it does now for teh 5xx variants?
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Jim,
Based on some of the posts on this thread, if one were to approximate the Likely Atlas Phase 1 performance at rougly 25-26mt to LEO, and 12-13mt to GTO, would one be in the ballpark?
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All ACES papers I seen talk about a 4.6m diameter which the internal diameter of the 5m fairing. Thus I would assume that the 4m version would a straight 4m fairing atop with the Common Upper Stage exposed but in the 5m case it would be enclosed.
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I was reading a ULA document from 2010, I wasn't aware of the design life of the engine. I knew they'd looked at re-usability, but I didn't know it was designed for 10 uses.
From the document: "The booster engine on the Atlas V, the RD-180, has several other features that enable practical reuse. It is a compact object fabricated with robust structures, as seen in Figure 1, yet it is not excessively heavy. Most importantly, it is an evolved version of the RD-170 engine designed for 10 operational uses. This last fact provides the foundation for economical reuse."
Anway, I thought I'd throw it out there that if they had have successfully pursued this and had it now been operational, then the current crisis would have been much less of a problem - even if they could re-use the existing engines just one more time.
http://www.ulalaunch.com/uploads/docs/Published_Papers/Evolution/EELVPartialReusable2010.pdf
Maybe worth a re-look? ("too late", she cried)
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I was reading a ULA document from 2010, I wasn't aware of the design life of the engine. I knew they'd looked at re-usability, but I didn't know it was designed for 10 uses.
From the document: "The booster engine on the Atlas V, the RD-180, has several other features that enable practical reuse. It is a compact object fabricated with robust structures, as seen in Figure 1, yet it is not excessively heavy. Most importantly, it is an evolved version of the RD-170 engine designed for 10 operational uses. This last fact provides the foundation for economical reuse."
Anway, I thought I'd throw it out there that if they had have successfully pursued this and had it now been operational, then the current crisis would have been much less of a problem - even if they could re-use the existing engines just one more time.
http://www.ulalaunch.com/uploads/docs/Published_Papers/Evolution/EELVPartialReusable2010.pdf
Maybe worth a re-look? ("too late", she cried)
But wouldn't you need some way of recovering the engine without it ever going into salt water. AV doesn't have that F9 pattern with 3/9 engines for boost back and 1/9 for landing. Ejecting the engine for mid-air parachute snag is pretty dicey and would require a heck of a lot of re-engineering. Just not quite sure how you'd recover it so that you could reuse it. BTW, the passage you quoted has awkward syntax and is not grammatically clear.
As written:
Most importantly, it is an evolved version of the RD-170 engine designed for 10 operational uses.
Possible meanings:
Most importantly, as an evolved version of the RD-170, it is designed for 10 operational uses.
Most importantly, it is an evolved version of the RD-170, which was designed for 10 operational uses.
Most importantly, it is a evolved version of the RD-170, and both were designed for 10 operational uses.
Nevertheless, the phrase most importantly as a modifier of it implies the RD-180 is designed for 10 uses.
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Let's eat grandma... Commas, they save lives ;)
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With the ban on the rd 180 seeming to become apparent would the F1 be the only man rated engine available without a massive investment in a brand new engine for Atlas 6 seeing as a rapid replacement is needed ?
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With the ban on the rd 180 seeming to become apparent would the F1 be the only man rated engine available without a massive investment in a brand new engine for Atlas 6 seeing as a rapid replacement is needed ?
As near as I can tell, an actual RD-180 "ban" seems less apparent every day.
F-1 is not available, and hasn't been since 1973 or thereabouts.
- Ed Kyle
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Yup but a 2 or 3 billion to build a new factory to build something that has already been built is far easier than starting a whole new high technology lab plus factory that costs about 10 billion .
US Congress might decide that having their precious voters at risk to a foreign despot might not be sensible.
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Yup but a 2 or 3 billion to build a new factory to build something that has already been built is far easier than starting a whole new high technology lab plus factory that costs about 10 billion .
US Congress might decide that having their precious voters at risk to a foreign despot might not be sensible.
OK, lets assume that there is an F-1B. What happens when one is stuck onto an Atlas 5 in place of an RD-180?
First , the big F-1B engine adds 3 tonnes of dry mass to the first stage, a nearly 14% increase.
Second, since F-1B produces twice as much thrust as RD-180, it will tear the Atlas 5 apart unless it can be massively throttled - something that F-1 did not do for Saturn. At its fixed full thrust it will produce more than 15 g acceleration near the end of the first stage burn.
Finally, since F-1B is a less efficient gas generator cycle engine, Atlas 5 payload to GTO will be cut by one-third. This assumes that the LOX and RP tanks can be resized to account for the different LOX to RP ratio of the engine.
The billions spent to create this engine would result in a rocket unable to even match Atlas 3A performance.
- Ed Kyle
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Yup but a 2 or 3 billion to build a new factory to build something that has already been built is far easier than starting a whole new high technology lab plus factory that costs about 10 billion .
US Congress might decide that having their precious voters at risk to a foreign despot might not be sensible.
OK, lets assume that there is an F-1B. What happens when one is stuck onto an Atlas 5 in place of an RD-180?
First , the big F-1B engine adds 3 tonnes of dry mass to the first stage, a nearly 14% increase.
Second, since F-1B produces twice as much thrust as RD-180, it will tear the Atlas 5 apart unless it can be massively throttled - something that F-1 did not do for Saturn. At its fixed full thrust it will produce more than 15 g acceleration near the end of the first stage burn.
Finally, since F-1B is a less efficient gas generator cycle engine, Atlas 5 payload to GTO will be cut by one-third. This assumes that the LOX and RP tanks can be resized to account for the different LOX to RP ratio of the engine.
The billions spent to create this engine would result in a rocket unable to even match Atlas 3A performance.
- Ed Kyle
Thanks but I was talking about LEO not GEO a manned launcher to carry astronauts is what I was talking about.
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Thanks but I was talking about LEO not GEO a manned launcher to carry astronauts is what I was talking about.
Similar conclusions can be drawn about a LEO mission, though the payload reduction would be one fourth instead of one third. This of course assumes use of a 2xRL10 Centaur.
- Ed Kyle
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So it would be an ok starter rocket but would cost way too much to construct a cheaper knockoff of the rd 180 is needed preferably with a bit more thrust .
I wonder what the next us manned rocket will look like ?
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So it would be an ok starter rocket but would cost way too much to construct a cheaper knockoff of the rd 180 is needed preferably with a bit more thrust .
I wonder what the next us manned rocket will look like ?
I think that it is already flying (including the RD-180 Atlas 5 possibility).
That aside, there would be a much better, though still imperfect, solution for Atlas 5 than F-1. Six Merlin 1D engines on a CCB carrying the same propellant mass as the current first stage would create a rocket that lost only 12.8% of its LEO performance and 14.2% of its GTO performance.
- Ed Kyle
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So it would be an ok starter rocket but would cost way too much to construct a cheaper knockoff of the rd 180 is needed preferably with a bit more thrust .
I wonder what the next us manned rocket will look like ?
I think that it is already flying (including the RD-180 Atlas 5 possibility).
That aside, there would be a much better, though still imperfect, solution for Atlas 5 than F-1. Six Merlin 1D engines on a CCB carrying the same propellant mass as the current first stage would create a rocket that lost only 12.8% of its LEO performance and 14.2% of its GTO performance.
- Ed Kyle
But would that not give Space X Monopoly on human spaceflight which is what NASA is trying to avoid .
Bet there will be a fantastic high teck program to develop the replace the rd 180 and the nk33 .
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Another way of looking at the situation.
Manufacture of the RD-180 is questionable because by 2022 licensing comes into question. Well industry has a traditional way of dealing with situations like that. Change the design just enough so it doesn't legally violate the patents.
That's why, as an engineer, I was encouraged to make my patents as broad and generic as possible. I noticed most people don't patent things that way or think about it in that manner.
Each patent has claims that limit it in the n-tupple space of all possible patents. From the point of view of patent lawyers a "good" patent grabs as large a region of n-tupple space as it can get away with. However, if it can be proven that a firm used an existing device and worked around it their claim is not as good. But, if a 3-party behaves as a clean room and comes up with a solution that they then use, why the patent is worked around.
That is what is done with much of the OpenSource software that gets around copyrights and patents. Then if put under a GNU license framework anybody can use the concept.
It can get rather close to "dirty" too and still be safe. For an example of that look at the Canon Hackers Tool Kit . CHDK, Google it.
The source of CHDK was frustration of the software folk doing the Matrix movies. In some of the scenes they needed to network tens of thousands of cameras. The miraculous appearance of CHDK, from Hungary with its weak cleanroom laws, let them network up to 64,000 Canon PowerShots. With the nature of the net, who knows if the real hack was in Hollywood or Hungary and nobody will ever know but now its a fine tool that millions of photographers have been using to do all sorts of amazing things you can't do with a stock camera. (Oh and I will point out that if SpaceX had used a hacked Canon Powershot instead of a MPEG-4 camera they could of recorded and transmitted much more useful information than the landing video now being restored)
So if 3rd parties including Patent lawyers looked the RD-180 and its patents over then published their analysis somewhere where LM, ULA and others could read it, I am sure all the patent issues could be worked around to make a legal patent free RD-180 derivative.
Taking it further a design patent is just change a look. A functional patent is a bit more but with thought tools like TRIZ (another Russian gift to the world) make it quite easy to figure out another method to achieve the same function.
It would be safe to make it "OpenSource" as so few in the world would be able to build one. Maybe, India, Japan, China and the EU. Plus the cost of creating such a production line would be more than most would dare. If they do then one has a situation akin to chip foundries and they have turned out okay for the market.
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Is the AJ-1E6 project to green as a replacement? The propulsion module is quite self-contained in the Atlas V and Antares.
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Is the AJ-1E6 project to green as a replacement? The propulsion module is quite self-contained in the Atlas V and Antares.
Yea, the interesting thing is AJR now has the NK-33 designs for their AJ engines. I think they'll have any info left over from PWR's RS-84. As I assume that info stayed with Rocketdyne.
And then they should/would be the one's with the RD-180 IP. Between those 3 different, but similar in performance, kerolox ORSC engines, they should be able to produce an engine that will be a drop in replacement for the russian RD-180 on Atlas V, but they'd call it something else, and it'd be different enough than RD-180 that they could get around the patent and licensing issues that watermod mentions.
It wouldn't be an RD-180, but it would be a drop in replacement. And built specifically to interface with the A5 mounts, propellant lines, and avionics with no core changes.
If there's money for that anyway.