So what would be the benefit of twin-thrust-chamber AJ-1E6 over just fitting 2x AJ26-500?A little simpler? But at the expense of higher capacity components up-stream of thrust chambers.T/W? But that's almost irrelevant for a booster.cheers, Martin
Quote from: MP99 on 08/19/2013 05:46 pmSo what would be the benefit of twin-thrust-chamber AJ-1E6 over just fitting 2x AJ26-500?A little simpler? But at the expense of higher capacity components up-stream of thrust chambers.T/W? But that's almost irrelevant for a booster.Ask ULA, which are using the twin-chamber RD-180 instead of twin RD-150's or 190's.
So what would be the benefit of twin-thrust-chamber AJ-1E6 over just fitting 2x AJ26-500?A little simpler? But at the expense of higher capacity components up-stream of thrust chambers.T/W? But that's almost irrelevant for a booster.
Quote from: Downix on 08/19/2013 06:20 pmQuote from: MP99 on 08/19/2013 05:46 pmSo what would be the benefit of twin-thrust-chamber AJ-1E6 over just fitting 2x AJ26-500?A little simpler? But at the expense of higher capacity components up-stream of thrust chambers.T/W? But that's almost irrelevant for a booster.Ask ULA, which are using the twin-chamber RD-180 instead of twin RD-150's or 190's.But, RD-180 existed when ULA signed up for it.If AJ26-500 is an "easy" upgrade from the Orbital variant, why then bother to make such a huge upgrade to a dual-thrust-chamber config?Cheers, Martin
Given the weight on risk than NASA has, the difference between three 1E6 and six 500 might be the deciding factor on the risk issue of their bid.
I thought that AJ's proposal was to use 4 AJ-1E6 on each booster, which would be more thrust than Dynetics' Pyrios with 2 x F-1B. It would take 8 of the 500s to match 4 AJ-1E6, but 7 of them would be just shy of 2 F-1Bs. How many AJ-500s could fit on a 5.5m dia. base anyway: 6, 7, 8? Seems to be stretching things.
Quote from: MP99 on 08/19/2013 06:33 pmQuote from: Downix on 08/19/2013 06:20 pmQuote from: MP99 on 08/19/2013 05:46 pmSo what would be the benefit of twin-thrust-chamber AJ-1E6 over just fitting 2x AJ26-500?A little simpler? But at the expense of higher capacity components up-stream of thrust chambers.T/W? But that's almost irrelevant for a booster.Ask ULA, which are using the twin-chamber RD-180 instead of twin RD-150's or 190's.But, RD-180 existed when ULA signed up for it.If AJ26-500 is an "easy" upgrade from the Orbital variant, why then bother to make such a huge upgrade to a dual-thrust-chamber config?Cheers, MartinAlso, turbo machinery likes to be big. The NK-33 thrust chamber can do 135% easily. So, it's not strange that if they intended to redo the TP they would rather only do the big one. Let's look at the potential clients:1) The original AJ-500 project was done to compete on the Air Force RLV project. Since it's cancelled, the original client is not there.
I know a company which seems to have no probs launching a LV with 9 rocket engines on a 3.66 meter wide first stage. (ducks and runs)
What RLV project was this, and do you have a link to a pdf?
Quote from: gospacex on 08/20/2013 05:18 amI know a company which seems to have no probs launching a LV with 9 rocket engines on a 3.66 meter wide first stage. (ducks and runs)Irrelevant really. Merlins are small enough physically and low enough thrust to cluster like that. They would be useless on a LRB.
I don't think you're getting it. Just because 9 150K lb, extremely light, and very small engines can fit close together - does not mean that a similar amount of 300-500K lb thrust engines can be clustered like that. There are weight issues, heat issues, among others. 5.5 M is not enough.
Quote from: newpylong on 08/20/2013 06:35 pmI don't think you're getting it. Just because 9 150K lb, extremely light, and very small engines can fit close together - does not mean that a similar amount of 300-500K lb thrust engines can be clustered like that. There are weight issues, heat issues, among others. 5.5 M is not enough. F9 is 3.66 meter diameter.Merlin's nozzle is 1.676 m diameter.NK-33's nozzle is 2 m diameter (1.193 times wider than Merlin).If NK-33s are to be mounted exactly the same way as Merlins on F9 but with all dimensions scaled by 1.2, the stage needs to be about 4.4 meters in diameter for them to fit under it.Why do you think 5.5 m stage wouldn't be enough?
Quote from: newpylong on 08/20/2013 06:35 pmI don't think you're getting it. Just because 9 150K lb, extremely light, and very small engines can fit close together - does not mean that a similar amount of 300-500K lb thrust engines can be clustered like that. There are weight issues, heat issues, among others. 5.5 M is not enough. I don't see significant heat issues for regen cooled chambers and nozzles. It's not RS-68 F9 is 3.66 meter diameter.Merlin's nozzle is 1.676 m diameter.NK-33's nozzle is 2 m diameter (1.193 times wider than Merlin).If NK-33s are to be mounted exactly the same way as Merlins on F9 but with all dimensions scaled by 1.2, the stage needs to be about 4.4 meters in diameter for them to fit under it.Why do you think 5.5 m stage wouldn't be enough?
Quote from: gospacex on 08/20/2013 07:11 pmQuote from: newpylong on 08/20/2013 06:35 pmI don't think you're getting it. Just because 9 150K lb, extremely light, and very small engines can fit close together - does not mean that a similar amount of 300-500K lb thrust engines can be clustered like that. There are weight issues, heat issues, among others. 5.5 M is not enough. I don't see significant heat issues for regen cooled chambers and nozzles. It's not RS-68 F9 is 3.66 meter diameter.Merlin's nozzle is 1.676 m diameter.NK-33's nozzle is 2 m diameter (1.193 times wider than Merlin).If NK-33s are to be mounted exactly the same way as Merlins on F9 but with all dimensions scaled by 1.2, the stage needs to be about 4.4 meters in diameter for them to fit under it.Why do you think 5.5 m stage wouldn't be enough?If Aerojet proposes a 5.5m wide LRB for SLS that uses four AJ-1E6's, then that's 8 nozzles in 4 pairs. Dunno if 9 would fit, but 8 will have to fit unless Aerojet goes with only 3 engines for 6 nozzles.
All very exciting.....but 5 nozzles might turn out a better design.
Quote from: Prober on 08/21/2013 01:46 pm All very exciting.....but 5 nozzles might turn out a better design.Assuming you mean five AJ-500's, that would only be 2500klbs of thrust, a full 1000klbs less than the 5-seg booster and Dynetics booster. There's an older spec sheet for SLS Block II with advanced liquid booster calling out three 1 Mlb " ORSC NHE"'s which I took to mean "Oxygen Rich Staged Combustion New Hydrocarbon Engines". So not sure if less thrust than that would work. So give AJ-500's might not be enough thrust. Even with the greater ISP, it still has to get off the pad with the NASA required minimum T/W ratio. That Block II also had the extra thrust of a 5th RS-25, so the booster might even need to be a little more thrust if SLS sticks with just four on the core in a Block 2B path.But that could be outdated information too, so not for sure...
So is that 3 engines per booster, and they have 1 or 2 chambers per engine?
Quote from: Lars_J on 09/02/2013 11:50 pmSo is that 3 engines per booster, and they have 1 or 2 chambers per engine?They say 2 x 550klbf chambers per engine. That's 3.3Mlbf per booster, with at least 297s of SL isp and 331s isp. That must give some amazing numbers.
Quote from: baldusi on 09/03/2013 02:06 amQuote from: Lars_J on 09/02/2013 11:50 pmSo is that 3 engines per booster, and they have 1 or 2 chambers per engine?They say 2 x 550klbf chambers per engine. That's 3.3Mlbf per booster, with at least 297s of SL isp and 331s isp. That must give some amazing numbers.2x "big, dumb, lower pressure" F1s vs 3x high-pressure "first time the US has done ORSC" engines. And 6x thrust chambers.I could see NASA coming back with "yeah, but do we want to use that on a launcher with astronauts?" NASA's LOM calculations (EG see full version of the ESAS appendixes) ratchet up pretty mercilessly as you add more engines, and those engines have worse failure modes.I wonder how 2x 1E6 would perform, just to try to keep the complexity down?cheers, Martin
Quote from: MP99 on 09/03/2013 07:12 amQuote from: baldusi on 09/03/2013 02:06 amQuote from: Lars_J on 09/02/2013 11:50 pmSo is that 3 engines per booster, and they have 1 or 2 chambers per engine?They say 2 x 550klbf chambers per engine. That's 3.3Mlbf per booster, with at least 297s of SL isp and 331s isp. That must give some amazing numbers.2x "big, dumb, lower pressure" F1s vs 3x high-pressure "first time the US has done ORSC" engines. And 6x thrust chambers.I could see NASA coming back with "yeah, but do we want to use that on a launcher with astronauts?" NASA's LOM calculations (EG see full version of the ESAS appendixes) ratchet up pretty mercilessly as you add more engines, and those engines have worse failure modes.I wonder how 2x 1E6 would perform, just to try to keep the complexity down?cheers, MartinI've seen those appendixes and I thought those were part of the thumbs in the scale of Griffin. If they keep applying those numbers, AJ should not even bother to present their bid. Which I find quite ridiculous since even a catastrophic TP failure (think of a Zenith-2 Tselina-2 #8 type of failure), wouldn't really be that different from other failure modes on the SLS stack. LOM and almost nil chances of LOC.Which is funny because when you let the commercial side chose a vehicle multiple chambered high pressure cycle or huge amount of engines doesn't seem to be a problem, apparently. In fact, the only GG cycle on the US fleet is not even considered.
Quote from: baldusi on 09/03/2013 02:06 amQuote from: Lars_J on 09/02/2013 11:50 pmSo is that 3 engines per booster, and they have 1 or 2 chambers per engine?They say 2 x 550klbf chambers per engine. That's 3.3Mlbf per booster, with at least 297s of SL isp and 331s isp. That must give some amazing numbers.Even with 600lbf less thrust than an F-1B LRB-powered SLS, the Isp jump is big enough the AJ-1-E6 LRBs ought to crush them in performance. I would bet, judging from the jump in SL Isp, that the performance jump might be 10% or more over their LRB competitor, depending on how big they make the LRBs. Alternatively they could make the LRBs shorter, but that seems like a waste. If you're going to offer the most complicated option and most advanced engine, I think it would pay to maximize performance to give yourself more of an edge.
Quote from: Hyperion5 on 09/03/2013 06:30 amQuote from: baldusi on 09/03/2013 02:06 amQuote from: Lars_J on 09/02/2013 11:50 pmSo is that 3 engines per booster, and they have 1 or 2 chambers per engine?They say 2 x 550klbf chambers per engine. That's 3.3Mlbf per booster, with at least 297s of SL isp and 331s isp. That must give some amazing numbers.Even with 600lbf less thrust than an F-1B LRB-powered SLS, the Isp jump is big enough the AJ-1-E6 LRBs ought to crush them in performance. I would bet, judging from the jump in SL Isp, that the performance jump might be 10% or more over their LRB competitor, depending on how big they make the LRBs. Alternatively they could make the LRBs shorter, but that seems like a waste. If you're going to offer the most complicated option and most advanced engine, I think it would pay to maximize performance to give yourself more of an edge. Well, if it has three engines, if there -was- a stand alone LV version of it (not saying there's a financial case for that), and if the AJ-1E6 could throttle down as low as the RD-180 (down to about 30% of maximum thrust...not sure if it can, but they are of fairly similar design, so maybe they can), then although they have limited fuel because they are an SLS booster and don't need a very long burn time, they could be throttled down shortly after lift off, and continue to be throttled down during ascent as applicable (to not pull too many g's, otherwise an overpowered booster like this would accelerate like crazy when not hauling up SLS's bulk). Which could mean those 3 AJ-1E6's could burn for quite a bit longer, and maybe get enough first stage performance to not need too big of an upper stage.
How much will the better impulse over the steel casing 5 segs effect performance? The 5 casings are 3.6 millions lbs/thrust - more than any advanced booster proposals I have seen.
Quote from: Lobo on 09/03/2013 06:07 pmQuote from: Hyperion5 on 09/03/2013 06:30 amQuote from: baldusi on 09/03/2013 02:06 amQuote from: Lars_J on 09/02/2013 11:50 pmSo is that 3 engines per booster, and they have 1 or 2 chambers per engine?They say 2 x 550klbf chambers per engine. That's 3.3Mlbf per booster, with at least 297s of SL isp and 331s isp. That must give some amazing numbers.Even with 600lbf less thrust than an F-1B LRB-powered SLS, the Isp jump is big enough the AJ-1-E6 LRBs ought to crush them in performance. I would bet, judging from the jump in SL Isp, that the performance jump might be 10% or more over their LRB competitor, depending on how big they make the LRBs. Alternatively they could make the LRBs shorter, but that seems like a waste. If you're going to offer the most complicated option and most advanced engine, I think it would pay to maximize performance to give yourself more of an edge. Well, if it has three engines, if there -was- a stand alone LV version of it (not saying there's a financial case for that), and if the AJ-1E6 could throttle down as low as the RD-180 (down to about 30% of maximum thrust...not sure if it can, but they are of fairly similar design, so maybe they can), then although they have limited fuel because they are an SLS booster and don't need a very long burn time, they could be throttled down shortly after lift off, and continue to be throttled down during ascent as applicable (to not pull too many g's, otherwise an overpowered booster like this would accelerate like crazy when not hauling up SLS's bulk). Which could mean those 3 AJ-1E6's could burn for quite a bit longer, and maybe get enough first stage performance to not need too big of an upper stage. I don't think we need to turn the SLS boosters into yet another LV. I think it would be enough to use the same engines as 2 other existing LVs (Atlas / Antares). Why split an already small volume of launches even further ?
Quote from: newpylong on 09/03/2013 06:13 pmHow much will the better impulse over the steel casing 5 segs effect performance? The 5 casings are 3.6 millions lbs/thrust - more than any advanced booster proposals I have seen.Thrust has very little bearing with performance. Specially when comparing solids vs liquids. First, you car about the whole stack T/W. And the compounded isp and propellant mass fraction.But just look at the proposals and the advanced solids proposal with 3.6Mlbf and composite casing and improved formula (excellent pmf and improved isp). And yet they can't quite reach 130tonnes without a 5th RS-25. Yet, the F-1B boosters have an expected performance of 150tonnes with 4 RS-25. And my guess is that AeroJet proposal will have even better performance.And the AJ-1E6 would solve the NK-33 stock problems and improve performance quite a bit on Antares. And could be a replacement on Atlas V if RD-180 was a problem. But considering that they've just extended the contract to 130 engines, unless the Russian bureaucrats do something really stupid, one SLS and Antares are real prospects.
However, I could even see a stronger case for a hydrolox booster powered by RS-68A...hypothetically. If SpaceX is able to start getting a piece of the government launch pie after 2015, then they may not need to pay ULA to maintain two EELV's. Since Delta IV is the LV which already has the 3-core heavy flying on both coasts, there's an argument that Atlas could be retired in favor of keeping Delta. SLS using a DCSS derived DUUS could lean in that direction too. So, ULA standardizes on just Delta IV with a 5m DCSS, perhaps upgrade to MB-60 on it. DUUS is DCSS derived with MB-60. SLS LRB's use boosters powered by 4-5 RS-68A's (2.86-3.6Mlbs at sea level respectively). Even with 5 RS-68's, that's one less nozzle than three AJ-1E6's.They seemed to think it was a feasible option in 2001 for an STS booster upgrade, and only 5.5m wide core. The MPS would probably have to be fatter though, but it can be because it won't need to fit through the VAB doors on the bottom.More Delta IV launches per year, and 10 more RS-68A's flying on every SLS launch would get that engine rate up, and as I understand, RS-68A is supposed to be pretty cheap at high volumes.And the US LV fleet is tightened up with hopefully some better economics of scale.
H2 is a horrendous fuel for a LEO booster. The tanks and the engines T/W is horrible. Look at the Delta IV LEO numbers. Specially the Medium. And the RS-68A is heavy even for an hydrogen engine. Plus, the ablative nozzle has very limited lifespan. But the main issue is that the boosters are volume limited. They can't be bigger than 5.5m, due to VAB size. So, you couldn't really put a booster much bigger than a Delta IV. You could put about 80% more propellant than a Delta IV core stage. And let's say that you add four engines (you can't fit more), that's 3Mlbf per booster. But you'd only have fuel for around 115s (back of the envelop calculation), that's even less than the SRB! I don't think you'd get much performance.
Now, if they had gone with an AJAX-like rocket, of course that the RS-68A boosters of the Heavy could have done wonders. With six cores I guess they'd had amazing performance. But that path was (regrettably) nor chosen.
....the main issue is that the boosters are volume limited. They can't be bigger than 5.5m, due to VAB size. So, you couldn't really put a booster much bigger than a Delta IV. You could put about 80% more propellant than a Delta IV core stage. And let's say that you add four engines (you can't fit more), that's 3Mlbf per booster. But you'd only have fuel for around 115s (back of the envelop calculation), that's even less than the SRB!...
Edit: I see you addressed this and posted 2 minutes before I did. I don't see all that raising the booster height and flaring out as viable design. I think they want the booster to attach to the core at the top of the booster.
BTW: the thread topic regards known progress on AJ-1E6. We are getting away from that.
Aerojet now owns the rights to RD-180 don't they?
Not exactly RD AMROSS has the rights. And PWC participation (49%, I believe) has yet to be transferred to AJ parent company (the Russian government has to allow it, which is part of the ongoing political issues).So the US could do a local RD-180, but I think they would have to do it through RD AMROSS. I guess Rocketdyne (and thus AeroJet) has the rights to the technology, though.But remember that the AJ proposal for SLS boosters is very "risky" for NASA's risk formula. And both ULA and Orbital are commercial companies. They won't buy it because it's cool, or even because it's American. They would buy it if and only if it made business sense. Thus, the true question is: Can AJ make the AJ-1E6 cheaply enough to be competitive in current (and future) market?
How would RD-180's get here if Aerojet decided they didn't want them here? (assuming existing contracts were met, just that new ones wouldn't be)
Could Aerojet box out the cheaper competition and not bring any more in, so as to -create- a market for the AJ-1E6? Or could Energomash just sign a deal with a different US company to import them into the US and make them available to ULA? Perhaps with ULA directly? And go around Aerojet-Rocketdyne entire?
Also, is sounds like Orbital is suing ULA for barring them from getting the RD-180, so they used the AJ-26/NK-33 instead?If the deal was between PWR and Energomash, how could ULA bar Orbital from getting them? I don't really understand that relationship. Does Orbital still want the RD-180 now that they are using AJ-26? I'd think if they switch engines, with would be more logical to go with another Aerojet engine rather than RD-180.
...Might USAF/DoD decide they don't want to support an LV that depends on a Russian supplied engine any more? Meaning, Atlas needs to find a domestic replacement, or Atlas goes away, and Delta is standardized for all government launches ULA gets?
Also, I was not aware that NASA deemed the Aerojet boosters as "risky". Is that just because they are staged combustion? Or for some other reason?
Yes, look at how they calculate risk. Staged Combustion is considered the riskiest of all. And the number of engines and thrust chambers is also the biggest. It's a statistics game, really. Gas Generator catastrophic failure is not really that bad, as SPX CRS-1 shown. And as Zenit-2 Teselin-2 #8 and NSS 8 shown, Stage Combustion failure modes can be nasty. Thus, the risk penalty on SC is huge. And again, you multiply that failure probability by the number of turbopumps. And the thrust chamber failure modes by the number of thrust chambers (including start failures). When you do it that way, the AeroJet proposal will be the most risky.Personally, I think is an exaggeration since they should only worry about LOM and LOC, and the truth is that even a TP explosion on the AJ boosters would mean the same as an early engine shutdown on the Pyros: LOM. Remember that you have to keep the boosters depleting the propellant at the same rate, else you move your CG asymmetrically and lots of nasty things happen. And SLS is assumed to be on the limit of performance, thus, even the loss of one F-1B midflight will probably mean LOM. And STS-51L shown quite clearly what a failure on a solid booster would mean (and the advanced ones would have like 50% more pressure).Now, let's suppose that you calculate LOC. I don't think that even a catastrophic failure like NSS 8 would mean LOC in a LRB. The engines are simply too far from the capsule, and you could shut down all orderly. That's the part that I don't like of the calculation. That and the fact that in real use, the SC cause one abort to orbit, while a SSSRB caused a LOM. And there were 3 SC vs 2 x SRB per STS flight.
I simply don't know the innards of the process. In particular, we don't know who will be at NASA nor Congress by the time comes to actually make the decision. And as far as I know, even the tender is not ready, thus, the parameters are totally unknown. I was just making a point about a potential disadvantage that I see in the AJ-1E6 project.
Yea, Dynetics has released a substantial amount of information re. Pyrios and ATK re their Dark Knights. We have heard almost nothing from AJ re. AJ-1E6. We don't know anything about how they are using that risk-reduction funding. Since those are public funds, aren't regular milestone reports required? I do wish some basic specs would be released. Then Steven Pietrobon could run those calculations you asked him to with some degree of accuracy. Like you, I would really like to know how this would compare with Pyrios on 4 engine core with 4 x MB-60 DUUS.
Here is my attempt at a review of the basic corporate relationships involving the various players discussed in this thread. I've skipped some details, such as Boeing's former ownership of Rocketdyne via. its acquisition from Rockwell International.Pratt & Whitney: Made RL-10 and jointly owned RD-AMROSS to import RD-180 from NPO Energomash. RD-AMROSS originally set up to import RD-180 for Lockheed Martin Atlas III, later used for Lockheed Martin (later United Launch Alliance) Atlas V. P&W was also licensed through RD-AMROSS to produce RD-180 in U.S.. United Technologies (UTC) owned P&W and currently still retains its RD-180 rights.Aerojet (Gencorp): Made AJ-10 and is licensed importer of NK-33, rebranded with new controller as AJ-26. Subsequently proposed new upgraded engines based on NK-33/AJ-26 for SLS booster.Rocketdyne: Original F-1, and J-2(X), SSME developer. RS-68 is most recent development.In 2005, UTC bought Rocketdyne to create Pratt & Whitney Rocketdyne.In 2013, Gencorp bough PWR to create Aerojet Rocketdyne, a company that currently builds RS-68, that is rebuilding an existing RL-10 engine inventory into a common EELV type, and that holds the NK-33 license, which currently consists of reconfiguring a limited inventory of 40 year old Russian engines for Antares.
Its planned acquisition of the RD-180 license is currently in limbo, as I understand things. If it gains RD-180 rights, it seems to me very likely that RD-180 will replace NK-33/AJ-26.
As far as I know it, they are completely unrelated. In particular, after Mishin's failure at N-1, he was replaced as head of Energyia by Glushko. Kutznesov's NK-15/33 family was an offense and was forbidden, and he directed his bureau to make a superior engine to that, thus, the RD-170 was born. Knowing how much Glushko hated the NK engines, I would be surprised that they shared any technology. May be they share some metallurgy, but I don't know the details.
Which then makes an interesting cross over to Steve Pietrobon thread about SLS trajectories. He was going to use some RD-180 data to model an AJ-1E6 powered SLS booster. Maybe he can just now model an SLS using four RD-180's directly?http://forum.nasaspaceflight.com/index.php?topic=32911.msg1111260#msg1111260
Quote from: Lobo on 10/28/2013 10:11 pmWhich then makes an interesting cross over to Steve Pietrobon thread about SLS trajectories. He was going to use some RD-180 data to model an AJ-1E6 powered SLS booster. Maybe he can just now model an SLS using four RD-180's directly?http://forum.nasaspaceflight.com/index.php?topic=32911.msg1111260#msg1111260I believe the RD-180 does not have enough thrust. It has a sea level thrust of 3827 kN, compared to 4893 kN for the AJ1E6. That's a 22% reduction. If we have 4x3827 = 15,308 kN, then that compares favourably with 3x4893 = 14,679 kN. So you would need four RD-180 engines on each booster to get the required performance.
I've only seen DUUS stages with either four RL-10 engines or four MB-60 engines, never two. I believe that's because that the maximum number of engines you can fit under a 5.5 m LOX tank. You don't want to fly with less as that's a significant payload hit.
Quote from: Steven Pietrobon on 10/29/2013 04:24 amI've only seen DUUS stages with either four RL-10 engines or four MB-60 engines, never two. I believe that's because that the maximum number of engines you can fit under a 5.5 m LOX tank. You don't want to fly with less as that's a significant payload hit.There's a certain Boeing AIAA paper from September floating around out there...you may be aware of it? :-)Page two in there has a chart that compares performance of the ICPS and the three DUUS engine options, to LEO, TLI, TMI, Titan, Europa, and Uranus missions. The DUUS options are one J2X, two MB-60's, or four RL-10's.There's even some art in there showing two MB-60 engines towards the back of the report.
Quote from: Lobo on 10/29/2013 04:44 amQuote from: Steven Pietrobon on 10/29/2013 04:24 amI've only seen DUUS stages with either four RL-10 engines or four MB-60 engines, never two. I believe that's because that the maximum number of engines you can fit under a 5.5 m LOX tank. You don't want to fly with less as that's a significant payload hit.There's a certain Boeing AIAA paper from September floating around out there...you may be aware of it? :-)Page two in there has a chart that compares performance of the ICPS and the three DUUS engine options, to LEO, TLI, TMI, Titan, Europa, and Uranus missions. The DUUS options are one J2X, two MB-60's, or four RL-10's.There's even some art in there showing two MB-60 engines towards the back of the report.Ahh, I forgot about that. I thought they were doing four MB-60 engines in that paper.
So each AJ-1E6 engine has two nozzles (like RD-180)?Edit: http://www.asee.org/Crumbly_ASEE_Final.pdf says it is.
And at that just > 5m booster dia, there may not be enough area for 4 engines and 8 nozzles.
At least we now have a miniscule amount more knowledge about the engine.
Yup. Still be very intersting to see how it all shakes out with the Aerojet aquisition of PWR. They would be the supplier of F-1B too. I'm sure Aerojet would supply F-1B's just fine if Dynetics wins the bid. But...as long as NASA would equally consider ORSC and GG kerolox engines from an engineering standpoint, Seems like AJR would sort of be at a conflict of interest to offer F-1B for the best price possible to compete against their own offering. Suddenly that F-1B might get kind of more expensive to develop, where an AJ-1E6 or four RD-180's might suddenly be pretty cheap.
So in general these seem to be true of the booster: Higher ISP than F-1B. Three AJ-1E6 is less thrust than two F-1B (3.3m lb. vs 3.6m lb.). That might suggest a longer burn time than four engines and at lower Gs, with greater gravity losses (but perhaps not throttle as deeply as a 4 engine variant). It might also suggest a longer burn time, lower Gs, and greater gravity losses than Pyrios, however Steven's extrapolated dia. of 5.1245m means less propellant volume than Pyrios, unless the tanks are longer, so the burn time (particularly with unknown throttling) cannot not be accurately specified.
Quote from: TomH on 10/29/2013 09:14 pmSo in general these seem to be true of the booster: Higher ISP than F-1B. Three AJ-1E6 is less thrust than two F-1B (3.3m lb. vs 3.6m lb.). That might suggest a longer burn time than four engines and at lower Gs, with greater gravity losses (but perhaps not throttle as deeply as a 4 engine variant). It might also suggest a longer burn time, lower Gs, and greater gravity losses than Pyrios, however Steven's extrapolated dia. of 5.1245m means less propellant volume than Pyrios, unless the tanks are longer, so the burn time (particularly with unknown throttling) cannot not be accurately specified.Throttling is not required as maximum acceleration is 31.85 m/s². My simulation gives a burn time of about 130 s, 10 s more than Pyrios. Total usable propellant is less as well, 696.6 t compared to 787.3 t for Pyrios. I get a total delta-V of 9564 m/s compared to 9579 m/s with Pyrios, which is not much difference.
Quote from: Lobo on 10/29/2013 10:41 pmYup. Still be very intersting to see how it all shakes out with the Aerojet aquisition of PWR. They would be the supplier of F-1B too. I'm sure Aerojet would supply F-1B's just fine if Dynetics wins the bid. But...as long as NASA would equally consider ORSC and GG kerolox engines from an engineering standpoint, Seems like AJR would sort of be at a conflict of interest to offer F-1B for the best price possible to compete against their own offering. Suddenly that F-1B might get kind of more expensive to develop, where an AJ-1E6 or four RD-180's might suddenly be pretty cheap. Why would they prefer AJ-1E6 over F-1B? Are they subcontracting the tank work on the AJ-1E6 design, and thus stand to make a little more profit as the prime?Otherwise, they win either way, so why not work hard on both designs? The thing I really dislike about your logic above is that I somewhat expect the F-1B to get more expensive to develop. After all, that's what previous studies of reviving it have all concluded. Sure, they are changing things up and trying to save money here and there, but those rosy projections don't always pan out, or they ignore all the things that have become more expensive. So, the thing that irks me is IF this entirely reasonable set of events happens, people will use exactly the logic you gave above as a conspiracy theory to explain why the F-1B didn't get revived. Grr.(For what it's worth, I expect finishing development on the AJ1E6 will be very expensive as well.)
Preburners GFE from AFRL to Aerojet
And it may well be that most of the profit of F-1B would go to Dynetics and only a small portion to AJR if F-1B were to win, whereas if AJ-1E6 won, all profit would go to AJR. As far as AJR asking NASA which engine they prefer up front, I think that may not be legal. I am sure Dynetics had lawyers who were smart enough to include hundreds of pages of legalese (don't they always) to cover every eventuality, including the possibility of RD being sold by PW to a competitor who might put its own entry in the competition. I seriously doubt Dynetics allowed itself to be placed in a position where AJR can simply ask NASA which engine it prefers them to pursue. Big time corporate lawyers are way too smart for that.
Also Lobo, you're drifting off into all those what if tangents again. I am absolutely convinced that NASA won't even begin to consider the majority of all those things you list.
OK, in my search to find out as much information on the AJ1E6 as possible, I found these two documents:S. Crumbly, "NASA's Space Launch System: Partnering for tomorrow," ASEE Eng. Research Council, Washington, DC, USA, Mar. 2013.http://www.asee.org/Crumbly_ASEE_Final.pdf
Proposed engine configuration:• 1.1M lbf class Oxygen Rich Staged Combustion (ORSC) engine• Liquid Oxygen and RP-1 propellants• Dual chamber design - Single turbopump assembly connected to 550k size preburners and main injectors/thrust chambers
Aerojet Rocketdyne is targeting a cost of $20-25 million for each pair of new AR-1 engines as the company continues to lobby the government to fund an all-new, U.S.-sourced rocket propulsion system, says Scott Seymour, president and CEO of the company’s parent, GenCorp.
So I think this is the AJ-1E6, now known as the AR-1 (much simpler)
sounds like a pretty good plan.
So I think this is the AJ-1E6, now known as the AR-1 (much simpler)QuoteAerojet Rocketdyne is targeting a cost of $20-25 million for each pair of new AR-1 engines as the company continues to lobby the government to fund an all-new, U.S.-sourced rocket propulsion system, says Scott Seymour, president and CEO of the company’s parent, GenCorp.http://aviationweek.com/defense/aerojet-rocketdyne-targets-25-million-pair-ar-1-enginesMight be aggressive, but Aerojet has been working on the engine for a few years on the back-burner and has experience with the AJ-26, sounds like a pretty good plan.
Quote from: Ronsmytheiii on 06/04/2014 11:22 pmSo I think this is the AJ-1E6, now known as the AR-1 (much simpler)QuoteAerojet Rocketdyne is targeting a cost of $20-25 million for each pair of new AR-1 engines as the company continues to lobby the government to fund an all-new, U.S.-sourced rocket propulsion system, says Scott Seymour, president and CEO of the company’s parent, GenCorp.http://aviationweek.com/defense/aerojet-rocketdyne-targets-25-million-pair-ar-1-enginesMight be aggressive, but Aerojet has been working on the engine for a few years on the back-burner and has experience with the AJ-26, sounds like a pretty good plan.Seems more likely this is what was originally referred to as AJ-500, at 500,000 lb thrust. The AJ-1000, renamed AJ-1E6 is a 1,000,000 lb thrust engine.
Now it sounds like they'll shelve the AJ-1E6 and rebadge the AJ-500 to the AR-1. And probably design it sepcifically to mount to the Atlas 5 with minimal changes to the LV.
Antares so be easy enough to adapt to it as the AR-1 would be about the same size as the AJ26. With more power, it'd probably need a core stretch though.
The Atlas V's RD-180 does about 850klbf, Antares does 723klbf. And in both LV assume two nozzles, The thrust chambers tested for the SLS program were 550klbf each. Thus, the AJ-1 was a dual chamber design. It could work on both the Atlas V and the Antares. If it were reduced to 550klbf, both LV would need two engines. I believe that they'll go with dual nozzle, 1Mlbf design.
So I think this is the AJ-1E6, now known as the AR-1 (much simpler
Quote from: Ronsmytheiii on 06/04/2014 11:22 pmSo I think this is the AJ-1E6, now known as the AR-1 (much simplerWay to butcher corporate heritage.Rocketdyne LR42 (AR-1) c. 1955. First flown on FJ-4F Fury on 16 July 1958.
it's probably cheaper and/or faster to develop a 500 klbf engine rather than a 1 Mlbf one. And that might be the critical element to replace the RD-180.
Quote from: baldusi on 06/08/2014 11:14 pmit's probably cheaper and/or faster to develop a 500 klbf engine rather than a 1 Mlbf one. And that might be the critical element to replace the RD-180.Agreed, and that alone is pretty compelling right now.Another (much more "pie in the sky") reason might be that a nine engine first stage has now been adequately flight proven. A stage using a cluster of nine 500 klbf engines is something that, just possibly, an entity smaller than NASA could develop. A stage using a cluster of nine 1 Mlbf engines on the other hand would have more thrust than an S-IC....
Could avoid SRBs by augmenting thrust from liftoff to before maxQ, potentially drop tank(s) (or stretch), then iSP advantage possibly enhanced with higher expansion nozzle given altitude/density of augmentation cut-off.
Quote from: Space Ghost 1962 on 06/08/2014 07:36 pmCould avoid SRBs by augmenting thrust from liftoff to before maxQ, potentially drop tank(s) (or stretch), then iSP advantage possibly enhanced with higher expansion nozzle given altitude/density of augmentation cut-off.I must be honest. All I can discern here is a series of run-on fragments, each of which has very little relation to the others. Your meaning is very unclear. There actually is no subject. You never explain how thrust could be augmented, but rather jump from phrase to phrase involving drop tanks, expansion nozzles, and so forth. If you want to communicate anything that can be understood by others, you need to go back to the basics of writing. A complete thought is expressed in a sentence. To use a sentence you nominate a subject (bring up something to talk about), then predicate (v) the subject (tell something about it). A paragraph is used to elaborate upon one main idea. Paragraph form most typically involves the use of a topic sentence to state a main idea. Detail sentences are then used to support the main idea through examples, elaboration, extension, etc. The main idea may be restated in a concluding sentence. Please, if you want anyone to take your thoughts seriously, you must learn to state those thoughts clearly.
Does anybody know status of AJ1e6, is it a paper rocket or have they actually built parts of it and tested them.
A hex plus center configuration of seven 500,000 lb. engines would be 3.5m lb. thrust per booster with a single center 0.5m lb thrust engine for landing.
Quote from: TomH on 09/14/2014 01:35 amA hex plus center configuration of seven 500,000 lb. engines would be 3.5m lb. thrust per booster with a single center 0.5m lb thrust engine for landing.That's a clever concept! Are you convinced the plumbing for the center engine would fit in the available space? See attached image.
"Paper" engine transitioning to metal via additive manufacturing, qualification of Mondaloy, titanium, copper and materials:http://aviationweek.com/space/engine-makers-pushing-am-other-technologies-rd-180-replacementCould see first fire in 2.5 years, depending on priorities, of course.
It's exciting and a move in the right direction, I think. However, I'm still curious why specifically takes so long to develop rocket engines. Seems we'd know the materials and fluids well by now, and the technologies used to build engines are know. I know it's not as easy as just heading to the shop and doing some work on a lathe or drill press. But 2.5 years is a really really long time with modern engineering and manufacturing capabilities.
But 2.5 years is a really really long time with modern engineering and manufacturing capabilities.
Quote from: wannamoonbase on 09/14/2014 06:48 am But 2.5 years is a really really long time with modern engineering and manufacturing capabilities.Modern engineering has also given us a million and one ways to test things.
But, J-2X got into its stride on the test stand much quicker than have previous engines.cheers, Martin
Quote from: MP99 on 09/14/2014 08:18 pmBut, J-2X got into its stride on the test stand much quicker than have previous engines.cheers, MartinStill about 4 years.
... probably better to have J-2s's better T/W ratio than J-2x's slightly improved Isp).
Quote from: rayleighscatter on 09/14/2014 10:22 pmQuote from: MP99 on 09/14/2014 08:18 pmBut, J-2X got into its stride on the test stand much quicker than have previous engines.cheers, MartinStill about 4 years....and was sold as being just a tweak on an already-heritage engine. Not a good comparison. (also, J-2x is really heavy... probably better to have J-2s's better T/W ratio than J-2x's slightly improved Isp).
how about using [AR-1] for SLS core stage after the stockpile of RS-25s run out?
Quote from: newpylong on 09/15/2014 05:31 pmhow about using [AR-1] for SLS core stage after the stockpile of RS-25s run out?Switching to a hydrocarbon engine would be extremely costly in both time and money as the entire launch infrastructure would have to be changed. It's not just the rocket.
Quote from: clongton on 09/15/2014 07:17 pmQuote from: newpylong on 09/15/2014 05:31 pmhow about using [AR-1] for SLS core stage after the stockpile of RS-25s run out?Switching to a hydrocarbon engine would be extremely costly in both time and money as the entire launch infrastructure would have to be changed. It's not just the rocket.Did you read what I wrote? I didn't say it was just the rocket.Dollar amounts being thrown out for new engines aren't exactly paltry either, though I would think in the long run cheaper than switching fuels. But that's why I posed the question.
Materials engineers at AJR have developed a set of alloys they have trademarked as “Mondaloy” that combines high strength with resistance to burning, making them particularly useful in the oxygen-rich, high-pressure environments that would be found inside the AR-1 and other oxidizer-rich, staged-combustion rockets.
If I recall properly, going far back enough in its development history, the AR-1 was originally the AJ-26-500, a reverse engineered and upgrade of the NK-33/AJ-26 used on the OSC Antares. Now, from what I've been seeing on the ORB-CRS-3 failure threads, it's becoming increasingly clear that there are serious concerns about the reliability of the NK-33 family's turbopumps with test failures in both Russia and the US and now the loss of an Antares in flight.Will this issue impact seriously on the AR-1 program?
Let's clarify this; I'm not asking whether NK-33 turbopumps would be flown but whether the AR-1's turbopumps would be NK-33 heritage (common design concepts and operating principles).
I don't think design is the problem. It's the fact that they are physically 40+ years old and were sitting around in a warehouse for 30 years before AR bought them.
Quote from: Ben the Space Brit on 11/06/2014 04:54 pmLet's clarify this; I'm not asking whether NK-33 turbopumps would be flown but whether the AR-1's turbopumps would be NK-33 heritage (common design concepts and operating principles).AR's website points towards all new new generation manufacture and construction for all AR-1 configurations. The website does lack details, but I'm entirely sure that we can trust them since didn't say anything about using refurbished engines components, right? I'm sure there is some Russian design elements, but I cannot be sure as to which engine family.
Quote from: russianhalo117 on 11/06/2014 05:00 pmQuote from: Ben the Space Brit on 11/06/2014 04:54 pmLet's clarify this; I'm not asking whether NK-33 turbopumps would be flown but whether the AR-1's turbopumps would be NK-33 heritage (common design concepts and operating principles).AR's website points towards all new new generation manufacture and construction for all AR-1 configurations. The website does lack details, but I'm entirely sure that we can trust them since didn't say anything about using refurbished engines components, right? I'm sure there is some Russian design elements, but I cannot be sure as to which engine family.Looks more like an RD series engine from what I can tell.
Quote from: JWarner on 11/07/2014 01:23 pmI don't think design is the problem. It's the fact that they are physically 40+ years old and were sitting around in a warehouse for 30 years before AR bought them.AR-1 is not 40 years old as none have been built yet. This is a new generation LRE with next generation design practices and new generation manufacturing technique such as its 3-D printed using CAD based software et cetera.
Quote from: arachnitect on 11/07/2014 03:44 pmQuote from: russianhalo117 on 11/06/2014 05:00 pmQuote from: Ben the Space Brit on 11/06/2014 04:54 pmLet's clarify this; I'm not asking whether NK-33 turbopumps would be flown but whether the AR-1's turbopumps would be NK-33 heritage (common design concepts and operating principles).AR's website points towards all new new generation manufacture and construction for all AR-1 configurations. The website does lack details, but I'm entirely sure that we can trust them since didn't say anything about using refurbished engines components, right? I'm sure there is some Russian design elements, but I cannot be sure as to which engine family.Looks more like an RD series engine from what I can tell.Looks more like the LR-87's assembly to me.
That resemblance has been noted before and I don't disagree.I was just looking at the AR-1 renderings alongside RD-180 and NK-33 schematics and was having a much easier time mapping bits of the AR-1 to the RD series schematic.In other words, I don't think AR-1 has much NK heritage.
Quote from: TrevorMonty on 02/09/2015 02:07 pmULA to help fund the AR-1 for a couple years.Plus there is government's $200m funding for a domestic engine, Aerojet may yet build this engine.http://m.decaturdaily.com/news/ula-s-ceo-talks-challenges-engine-plant-plans-for-decatur/article_8ba49046-af4a-11e4-97ef-ff58591d43fc.html?mode=jqmI don't understand how AR-1 can be a "backup" for BE-4, since the two engines use completely different fuels. ULA would have to also design a "backup" rocket - unless it intends AR-1 to be a straight up RD-180 replacement, in which case AR-1 is still not a "backup" because it would mean keeping the current Atlas 5/Delta 4 lineup. - Ed Kyle
ULA to help fund the AR-1 for a couple years.Plus there is government's $200m funding for a domestic engine, Aerojet may yet build this engine.http://m.decaturdaily.com/news/ula-s-ceo-talks-challenges-engine-plant-plans-for-decatur/article_8ba49046-af4a-11e4-97ef-ff58591d43fc.html?mode=jqm
A general unwillingness on the part of both Aerojet and PWR to invest in engine development without a solid customer to foot the bill may yet cost them dearly. With Blue Origin seeming to possibly about to take away ULA's NGLV business and Delta-IV and Atlas-V going away, AJR may find themselves without any business at all in as little as a decade beyond SLS at a rate of, what, eight engines a year spread across two models?
Quote from: Ben the Space Brit on 02/12/2015 11:41 amA general unwillingness on the part of both Aerojet and PWR to invest in engine development without a solid customer to foot the bill may yet cost them dearly. With Blue Origin seeming to possibly about to take away ULA's NGLV business and Delta-IV and Atlas-V going away, AJR may find themselves without any business at all in as little as a decade beyond SLS at a rate of, what, eight engines a year spread across two models?To be fair no company has developed an engine without a rocket or customer footing the bill. SpaceX and Blue both had a rocket meant to go with their engines. A new engine is going to cost a huge amount of money to design and build. I don't think it is logical to expect Aerojet or PWR to have sunk hundreds of millions of dollars into developing an engine with only the hope that someone someday might buy it. That would be an awfully large amount of money to gamble. Also these engine projects take years. Not even one year ago the RD-180 looked safe. It would be difficult to produce an engine which could compete with it. The RD-180's development cost were paid long ago and its production labor is cheaper. There wasn't a good reason to replace it. Blue just happened to be developing an engine with close enough to what ULA was looking for when they needed to stat looking for a replacement. However Blue was doing that for their own rocket project and no because they hoped to sell it to a third party. It just happened to work out that way.
Quote from: notsorandom on 02/12/2015 01:07 pmQuote from: Ben the Space Brit on 02/12/2015 11:41 amA general unwillingness on the part of both Aerojet and PWR to invest in engine development without a solid customer to foot the bill may yet cost them dearly. With Blue Origin seeming to possibly about to take away ULA's NGLV business and Delta-IV and Atlas-V going away, AJR may find themselves without any business at all in as little as a decade beyond SLS at a rate of, what, eight engines a year spread across two models?To be fair no company has developed an engine without a rocket or customer footing the bill. SpaceX and Blue both had a rocket meant to go with their engines. A new engine is going to cost a huge amount of money to design and build. I don't think it is logical to expect Aerojet or PWR to have sunk hundreds of millions of dollars into developing an engine with only the hope that someone someday might buy it. That would be an awfully large amount of money to gamble. Also these engine projects take years. Not even one year ago the RD-180 looked safe. It would be difficult to produce an engine which could compete with it. The RD-180's development cost were paid long ago and its production labor is cheaper. There wasn't a good reason to replace it. Blue just happened to be developing an engine with close enough to what ULA was looking for when they needed to stat looking for a replacement. However Blue was doing that for their own rocket project and no because they hoped to sell it to a third party. It just happened to work out that way.BO started development of BE-4 in 2011 but didn't sign any agreement with ULA until 2014. Who were they developing it for?
Themselves, they were/are working on a reusable launch vehicle which would use the BE-4 as the first stage propulsion. As Tory Bruno puts it though Blue is very shy so not much is known about that project.
Quote from: Ben the Space Brit on 02/12/2015 11:41 amA general unwillingness on the part of both Aerojet and PWR to invest in engine development without a solid customer to foot the bill may yet cost them dearly. With Blue Origin seeming to possibly about to take away ULA's NGLV business and Delta-IV and Atlas-V going away, AJR may find themselves without any business at all in as little as a decade beyond SLS at a rate of, what, eight engines a year spread across two models?To be fair no company has developed an engine without a rocket or customer footing the bill. SpaceX and Blue both had a rocket meant to go with their engines. A new engine is going to cost a huge amount of money to design and build. I don't think it is logical to expect Aerojet or PWR to have sunk hundreds of millions of dollars into developing an engine with only the hope that someone someday might buy it. That would be an awfully large amount of money to gamble.
Quote from: notsorandom on 02/12/2015 01:07 pmQuote from: Ben the Space Brit on 02/12/2015 11:41 amA general unwillingness on the part of both Aerojet and PWR to invest in engine development without a solid customer to foot the bill may yet cost them dearly. With Blue Origin seeming to possibly about to take away ULA's NGLV business and Delta-IV and Atlas-V going away, AJR may find themselves without any business at all in as little as a decade beyond SLS at a rate of, what, eight engines a year spread across two models?To be fair no company has developed an engine without a rocket or customer footing the bill. SpaceX and Blue both had a rocket meant to go with their engines. A new engine is going to cost a huge amount of money to design and build. I don't think it is logical to expect Aerojet or PWR to have sunk hundreds of millions of dollars into developing an engine with only the hope that someone someday might buy it. That would be an awfully large amount of money to gamble. Only in the world of these government contractors would that be such a consideration. In most other areas, corporation actually do have significant research and development budgets (gasp) to develop new products where there are no customers yet.Don't act like PWR/Aerojet is in the poor house. They have had plenty of income over the years. But they won't lift a finger to actually do real development without a fat contract.
Quote from: notsorandom on 02/12/2015 01:07 pmQuote from: Ben the Space Brit on 02/12/2015 11:41 amA general unwillingness on the part of both Aerojet and PWR to invest in engine development without a solid customer to foot the bill may yet cost them dearly. With Blue Origin seeming to possibly about to take away ULA's NGLV business and Delta-IV and Atlas-V going away, AJR may find themselves without any business at all in as little as a decade beyond SLS at a rate of, what, eight engines a year spread across two models?To be fair no company has developed an engine without a rocket or customer footing the bill. SpaceX and Blue both had a rocket meant to go with their engines. A new engine is going to cost a huge amount of money to design and build. I don't think it is logical to expect Aerojet or PWR to have sunk hundreds of millions of dollars into developing an engine with only the hope that someone someday might buy it. That would be an awfully large amount of money to gamble. Only in the world of these government contractors would that be such a consideration. In most other areas, corporations actually do have significant research and development budgets (gasp) to develop new products where there are no customers yet.Don't act like PWR/Aerojet is in the poor house. They have had plenty of income over the years. But they won't lift a finger to actually do real development without a fat contract.