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#100 by Herb Schaltegger on 05 Sep, 2013 23:29
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Are you saying hot, high-pressure oxygen-rich environments are often used for nuclear materials processing?
Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue.
Which was my first point that no one actually responded to several pages ago. -
#101 by Robotbeat on 05 Sep, 2013 23:48
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Okay, I know they /could/ do it, but even still the specific alloys suited for the environment still isn't something the US has some living experience with. UF6 is one thing, high temperature/pressure oxygen is another. Both harsh, both corrosive, but the requirements are different enough that I doubt the necessary alloys are the same.Are you saying hot, high-pressure oxygen-rich environments are often used for nuclear materials processing?
Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue.... -
#102 by strangequark on 05 Sep, 2013 23:58
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Okay, I know they /could/ do it, but even still the specific alloys suited for the environment still isn't something the US has some living experience with. UF6 is one thing, high temperature/pressure oxygen is another. Both harsh, both corrosive, but the requirements are different enough that I doubt the necessary alloys are the same.Are you saying hot, high-pressure oxygen-rich environments are often used for nuclear materials processing?
Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue....
We have the alloys. There's not much on it, but lookup Mondaloy. -
#103 by asmi on 06 Sep, 2013 00:35
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Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue.
This isn't about technology anymore, is it?
If it is, you should have no problems telling us which components of nuclear reactor contain oxygen at temperature of around 3000K at pressure 3,868 psia (almost 270 times higher than atmosphere pressure)? -
#104 by Robotbeat on 06 Sep, 2013 02:16
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interesting! Metallurgy is a pretty interesting topic to me... I'd like to learn more.
Okay, I know they /could/ do it, but even still the specific alloys suited for the environment still isn't something the US has some living experience with. UF6 is one thing, high temperature/pressure oxygen is another. Both harsh, both corrosive, but the requirements are different enough that I doubt the necessary alloys are the same.Are you saying hot, high-pressure oxygen-rich environments are often used for nuclear materials processing?
Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue....
We have the alloys. There's not much on it, but lookup Mondaloy. -
#105 by Herb Schaltegger on 06 Sep, 2013 02:19
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Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue.
This isn't about technology anymore, is it?
Changing the subject back to what I actually wrote, and not about your and Chris' attempt to sidetrack it, it's never been simply about the technology. It's always been about the money. Certain segments of U.S. industry know very well how to deal with metallurgy for precision applications in chemically difficult conditions. As I have actually written (three times in this thread now, for those of you playing along at home and keeping track of the subject at hand), is that if this whole issue turns into something more than a drumbeat to renegotiate RD-180 prices, U.S. industry would have little real difficulty manufacturing an RD-180 equivalent engine IF THE MONEY WAS FOUND TO DO SO.
Alternately, and a lot more likely, NRO and DOD would simply switch payloads to DIV variants and say screw it. But if it the United States absolutely had to have an oxygen-rich staged combustion engine, it could be done. -
#106 by arachnitect on 06 Sep, 2013 02:35
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I don't think what Herb is talking about is in reactors, it's stuff that happens in fuel processing and warhead fabrication.Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue.
This isn't about technology anymore, is it?
If it is, you should have no problems telling us which components of nuclear reactor contain oxygen at temperature of around 3000K at pressure 3,868 psia (almost 270 times higher than atmosphere pressure)?
The problem as I see is not that the Aerojet/RD folks couldn't handle the oxy-rich issue, it's that they basically need to replicate the exact process the Russians are using in order to preserve engine commonality.
I may be wrong about this, but I thought that in addition to the material properties there are geometry problems as well... you need to control the way the gas moves through the engine. Since the engineers have access to complete engines this shouldn't be issue though.
General Staged Combustion thread -
#107 by Herb Schaltegger on 06 Sep, 2013 02:58
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I don't think what Herb is talking about is in reactors, it's stuff that happens in fuel processing and warhead fabrication.
Bingo! And I doubt you'll find anyone familiar with those processes who would agree with the idea that oxygen-rich staged combustion is harder or "worse" to deal with than the issues involved with processes involving fluorine and radioactive trans-uranic elements. -
#108 by Proponent on 06 Sep, 2013 10:32
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By the way, not that that's the same as ORSC, but way back in the 1930s Robert Goddard drove turbopumps with oxygen-rich gas. (Then again, in his early rockets both oxygen tanks and fuel tanks were pressurized with gaseous oxygen!)
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#109 by edkyle99 on 06 Sep, 2013 14:20
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... it's never been simply about the technology. It's always been about the money.
That's right.
During the SLS Mission Concept Review (MCR) Requirements Analysis Cycle (RAC) a couple years ago, RAC Team 2 studied a plethora of kerosene fueled rocket concepts for SLS. These included gas generator (GG) and oxygen rich staged combustion (ORSC) concepts, including one design that used ORSC for both the first and second stage. After comparing numerous concepts, Team 2 chose GG over ORSC, "due to lower engine development risk and less costly growth options".
Falcon 9 versus Atlas V and/or Antares would be a marketplace test of GG versus ORSC if all of the engines were built in the same country.
- Ed Kyle -
#110 by Prober on 06 Sep, 2013 14:43
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Nope. I'm sating that the chemistry and metallurgy of highly-reactive materials in high pressure (and for that matter very low pressure) environments is a lot more well-understood in some areas of industry anyone in this thread seems to think. The blanket throw-away statement that basically only ex-Soviet/Russian metallurgists could ever understand the issues involved in oxygen-rich staged combustion is complete nonsense. There are a LOT of highly-specialized metallurgists in any nuclear-capable nation who understand this kind of stuff and could build an RD-180 or equivalent, given the appropriate financial support. The fact that you mention fluorine is your clue.
This isn't about technology anymore, is it?
If it is, you should have no problems telling us which components of nuclear reactor contain oxygen at temperature of around 3000K at pressure 3,868 psia (almost 270 times higher than atmosphere pressure)?
The problem as I see is not that the Aerojet/RD folks couldn't handle the oxy-rich issue, it's that they basically need to replicate the exact process the Russians are using in order to preserve engine commonality.
General Staged Combustion thread
Its a known issue(s). Watching Aerojet with getting Antares up ready their experience level is up there. -
#111 by Antares on 06 Sep, 2013 14:52
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If the knowledge exists domestically, then why hasn't it been applied to ORSC LPREs?
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#112 by strangequark on 06 Sep, 2013 15:43
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If the knowledge exists domestically, then why hasn't it been applied to ORSC LPREs?
Cost of developing a staged combustion engine, ox-rich or no, has been the biggest factor there, and you know it. For Goddard's sake, we've only developed two flight engines in the two decades since the West was made aware of ORSC engine work in Russia. RS-68 is hydrogen, so the tech was inapplicable, and Merlin was designed to be easy and low cost.
Sadly, the appetite for building new engines in this country just isn't there anymore, regardless of cycle. -
#113 by Robotbeat on 06 Sep, 2013 17:18
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...For Goddard's sake...
I'm stealing that. -
#114 by sdsds on 06 Sep, 2013 18:38
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I think the Russians know that by selling RD-180 at a price point not very far above their cost they have effectively quashed investment in U.S. development and production of similar engines.
USAF assessed the ability of ULA to continue flying Atlas if new shipments of RD-180 were halted. USAF had full insight into ULA and RD-AMROSS activities. With that insight USAF is satisfied the propulsion needs of Atlas will be met. Who are we to question that conclusion? -
#115 by Lobo on 06 Sep, 2013 18:57
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Alternately, and a lot more likely, NRO and DOD would simply switch payloads to DIV variants and say screw it.
@This.
Atlas and Delta are two LV's that really do the same thing, and were inteded for one or the other to win the EELV competition for the exact same role. Maybe one's a little better for some things, and the other's a little better for other things. But they were both designed to meet the USAF's specifications, so I'm assuming they both can. It's just been USAF that's determined they wanted ULA to operate both instead of settling on one or the other...and will pay for that.
Given ULA's current flight rate, I don't think they have enough launches a year to max out a single EELV, much less two.
Unless they were to add a bunch of commercial lauches, I'd bet that the Delta IV line and facilities could handle their government payload manifests just fine.
If ULA -could- add a fair amount of commercial launches, I think they still could handle it. As more payloads launch form the Eastern Range than the western, they could always add another tower and MSS to LC-37, as there are two pads there, and have consolidated operations at one launch complex. Not many payloads, Government or commercial, launch from the Western Range so I would expect SLC-6 could handle all potential government and commercial launches for some time. Especially with SpaceX getting some of the limited commercial launches there.
But if it the United States absolutely had to have an oxygen-rich staged combustion engine, it could be done.
Interesting question...-is- there really a need for a US ORSC engine?
SpaceX doesn't think so for their current operations, and are exploring it only for a methane application, where they don't want to use RP-1 or LH2.
I don't know for sure, but I think a big reason LM went with RD-180 was that they could get it pretty cheap, and save themselves having to develop a new booster engine, staged combustion or otherwise. It existed, and had good perfomance. They'd went to it originally with the Atlas III, and then carried it over to the new Atlas V. I think Atlas V was basically a bit bigger core than the Atlas III, and a CBC core which could mount SRB's or outboad boosters, per the EELV competition requirements? (Where Atlas III could not?)
If I understand that correctly, then nothing magic about ORSC there, just price and availability.
McDonnel-Douglas opted for a new LH2 engine from Rocketdyne, as they were about the only US engine making option, and they had really only been doing LH2 in the RL-10 and RS-25 engines for years. (and maintaining rather than really pursuing RS-27A in RP-1? A decades old design).
Sounds like RS-68 was pretty simple, and a simple GG. Far more simple that RS-25. Development went pretty smooth. And even a GG LH2 engine crushes ORSC in ISP...338s vs. 410s vac. (but obviously has other drawbacks)
72s higher for GG LH2 vs ORSC RP-1.
Conversely, even a GG RP-1 such as the M1D (booster version) will have a vacuum ISP of only about 28s less than RD-180, and even the old RS-27A had an ISP of only about 36s less.
And the RS-68 would/could be pretty cheap if made in sufficient quantities.
So...-does- the US -really- need an RP-1 ORSC engine?
I don't know that the US really even needs Atlas V as long as there's Delta IV. SpaceX has a pretty loaded manifest with their cheap and dirty GG RP-1 engines...so all seems good there. And SLS, in it's current core design, probably doesn't beenfit from ORSC vs. GG if it were to go with liquid boosters. The burn time of the boosters is too short. (It would for AJAX, smaller core and would keep the Atlas V/RD-180 boosters for 100s more than SLS LRB. That was part of the core design).
Antares probably does need ORSC engine as that's what what it's designed to have...but does the US really -need- Antares? Falcon and Delta could launch Cygnus if need be.
Well, if we really need it, as Herb said, I'm sure we can do it (AJ-1E6, RS-84, or US-built RD-180)...but do we really need to replace RD-180 if the Russians stop selling it to us?
That's a fair point I think.
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#116 by Lobo on 06 Sep, 2013 18:58
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Can we rename this thread, "From Russia with Love"?
;-)
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#117 by Lobo on 06 Sep, 2013 19:13
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I think the Russians know that by selling RD-180 at a price point not very far above their cost they have effectively quashed investment in U.S. development and production of similar engines.
Isn't that also sort of what ArianeSpace did with the commercial US launch market? Priced so ULA couldn't compete with Atlas V, and so no new investment in a new US launch provider for several years to try to compete once ULA sort of gave up and focused on government launches? Until Elon decided to go for it anyway. And later, OSC.
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#118 by Lurker Steve on 06 Sep, 2013 20:23
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If the knowledge exists domestically, then why hasn't it been applied to ORSC LPREs?
Cost of developing a staged combustion engine, ox-rich or no, has been the biggest factor there, and you know it. For Goddard's sake, we've only developed two flight engines in the two decades since the West was made aware of ORSC engine work in Russia. RS-68 is hydrogen, so the tech was inapplicable, and Merlin was designed to be easy and low cost.
Sadly, the appetite for building new engines in this country just isn't there anymore, regardless of cycle.
So, only 10 years ago, Boeing-Rocketdyne was still working on the RS-84, which was I assume also was an ORSC RP-1/LOX engine. The articles say the engine made it to the PDR level, so I assume most of the materials challenges must have been worked out by then, correct ?
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#119 by arachnitect on 06 Sep, 2013 20:26
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Alternately, and a lot more likely, NRO and DOD would simply switch payloads to DIV variants and say screw it.
@This.
Atlas and Delta are two LV's that really do the same thing, and were inteded for one or the other to win the EELV competition for the exact same role. Maybe one's a little better for some things, and the other's a little better for other things. But they were both designed to meet the USAF's specifications, so I'm assuming they both can.
The problem with going to Delta IV is it throws NASA under the bus. NASA relies on Atlas V for science missions and doesn't even bother with Delta IV. 2 of the CCP providers bid Atlas V as their LV. Then there's the whole situation with Orbital, who need an ORSC engine if they want to fly more COTS missions.
If Russia did block further RD-180 export, Orbital might win by getting access to the US built RD-180.
