|
|
Thread Tools | Display Modes |
#21
|
|||
|
|||
RD-180 relplacement
Jeff Findley wrote:
In article , says... Jeff Findley wrote: In article , says... I'm confused. The program to replace the RD-180 is focused on engines with around 400,000 lb thrust at sea level. This focuses them on the AR-1 (kerosene/LOC) and BE-4 (methane/LOX). Why are they not looking at the RS-25 (LH2/LOX with similar thrust) or the Raptor engine (methane/LOX)? RS-25 is hella expensive and ULA already knows that LH2/LOX produces a large, expensive, vehicle (e.g. Delta IV). So that's right out since Delta IV is already flying (no development costs there). But do note that ULA really wants to ax Delta IV in favor of Atlas V due to its high cost. So why aren't they using something other than RS-25 on SLS? Because the cheaper RS-68, used on Delta IV, isn't regeneratively cooled and can't handle the heating environment at the base of the core stage caused by both the main engines and the SRBs. This was discovered early on in Ares V development, which planned on using the much cheaper RS-68. In general, Ares V/SLS is a giant cluster *&^# of a program. If it ever does fly it will be the biggest, most expensive, lowest flight rate launch vehicle in history. I'm inclined to say that RS-25 'won' the studies because it got extra points for being 'Shuttle-derived', which was a stupid requirement in the first place. Raptor (methane/LOX) isn't "fully baked" yet (BE-4 is ahead of it). That sounds wrong to me. SpaceX test fired a full up Raptor engine (albeit a lower thrust developmental engine) at their Texas facility last year. The BE-4 has never been test fired and they didn't even have a full engine put together until this year. I should say it's my opinion that Raptor is behind BE-4. Since both companies are private and somewhat secretive, good information is hard to come by. But from what's been reported in the press, Blue Origin has a full size complete BE-4 development engine built and is getting ready to test fire it. SpaceX could be at that point too but all I've heard so far is that they've fired a lower thrust development engine, which indicates they're not quite ready for full scale testing. Blue Origin, on the other hand, thinks BE-4 is ready for "full scale" testing. But the proof will be on the test stand, will it not? Blue Origin says BE-4 will be ready for delivery this year (or they did; not sure if that's still their story now). Blue Origin has more schedule pressure for this class engine than SpaceX does, since they want it picked up by ULA for the engine for Vulcan (2020-2021 launch dates) and the big thing they're touting is that it will be available sooner than AR-1, which is the alternative engine. That being said, BE-4 has apparently moved right at least some number of months, since originally the full up engine tests were supposed to start last year but they've only just got complete engines built. Meanwhile, SpaceX has no real schedule driver for Raptor other than internal (ITS 2024 or so, which could easily move right) and their real priority development right now is Falcon Heavy. Seems like we're getting a lot of different engines when it might be more efficient to settle on just a couple. AR-1 is a "backup" engine at this point since it's so far behind BE-4 in both schedule and (estimated) per unit price. But, AR-1 is about the right size for two of them to be a "drop-in" replacement for RD-180 on Atlas V. So, if ULA stumbles on Vulcan, an AR-1 engined Atlas V might be a good stop-gap measure. Aerojet Rocketdyne says they can start delivering AR1 engines in 2019, so the finish line isn't all that far behind BE-4. Blue Origin says the BE-4 will cost 60% of what an AR1 costs (at $12.5 million each); so BE-4 engines are only around $7.5 million each? The government is paying a lot of money to develop AR1, so I'd bet on it being pushed for use somewhere. And AR1 does have the advantage of not needing a bunch of new infrastructure to handle fueling and such. ULA is more worried about the per flight cost down the road. If they have to install liquid methane tanks and plumbing, they'll do it to lower costs. SpaceX is already undercutting *everyone* on launch costs and that's without taking reuse into account. ULA is desperate to stay alive at this point with SpaceX eating into its DOD launches that it used to have a monopoly on. ULA is saying that base Raptor (with no solids) will cost around $100 million per launch. That gets you around 10 tonnes to LEO. Current Falcon 9 has double the payload and is only 2/3 the cost, which makes it about 1/3 the cost per pound. So ULA's new best effort at economy still costs 3x what the competition costs. At any rate, Aerojet Rocketdyne is being paid good money to develop AR- 1. Even if it meets the same fate as J-2X, they're getting money now which helps keep the company alive. How many billion dollars of taxpayer money are we going to spend developing engines that never get used? Around $1.5 billion for AR1. Around $1.2 billion for RS-25 (which only gets used if SLS keeps flying). Another $1.2 billion for J-2X. Meanwhile Merlin engines used on Falcon 9 cost around $1.2 million each with engines in the Raptor/BE-4 class going for $7.5 million each? Meanwhile the entire development budget for New Glenn is around $2.5 billion and what little public data there is puts development costs for Raptor engines in the hundreds of millions of dollars (vice billions) and I expect BE-4 development is similar. What that says is that private companies developing engines mostly on their own nickel is looking to be an order of magnitude cheaper than traditional contracted engine development programs... Maybe the US Government should get out of the game of funding development of engines and launch vehicles. SpaceX and Blue Origin have both proven that private industry can do this themselves, with sufficient funding. USAF has (mostly) gone this direction. NASA hasn't. What NASA needs to do is put together performance requirements specs for what they want and then be flexible about trading away requirements for schedule and dollars to commercial vendors. Along the lines of "You want X, Y, and Z. We can give you X and Y in A years for B money, but Z will double the cost and schedule. How badly do you need Z?" AJR sat on its ass for how long after RD-180 was picked for Atlas? They've known for *decades* that the US needed a high thrust LOX/kerosene engine to remain competitive in the global launch market and they literally sat on their hands waiting for a government handout to start development. AJR deserves to go under at this point. It's management is wholly dependent on old style cost-plus contracts. They don't know how to innovate. They don't know how to compete on cost. Yep. But they've been burned before on developing engines and not being able to sell them after, so I can kind of understand why they would risk a billion of their own money. Since they don't make vehicles, engine development is riskier for them. NASA and DOD need to switch their space support back to the same style of support that NACA used to give to aircraft and (jet) engine manufacturers in the US. NACA didn't design and build commercial engines or aircraft. And NACA certainly didn't operate its own airlines. It's well past time for the US Government to get the hell out of the launch business and let good old fashioned capitalism and market based competition sort out the cheapest way to orbit. Yep, it's past time for this change. For what they're spending on SLS/Orion development NASA could have pretty much funded the total development of both ITS from SpaceX and New Glenn from Blue Origin and had change left. This is the kind of **** that the "crazy" people on the old sci.space argued for back in the early 1990s when they were pushing CATS (cheap access to space). It's now been over 30 years since then, and SpaceX has proven them right. The government needs to get the *&%# out of the way and support the commercial providers rather than building yet another Government Luanch System which will be a drain on NASA's budget for decades to come. Yep, I remember that. Even back then people were saying 'performance uber alles' was the wrong approach and proposing things like 'big dumb boosters' and accepting the addition weight of using swaged steel rather than aluminum because of the cost advantage. But it kind of took Elon Musk to find the right path to cheaper launches. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
#22
|
|||
|
|||
RD-180 relplacement
Jeff Findley wrote:
In article , says... space x engines are built by robotics, the engine bells are made on 3d printers No Bob, I do not believe the Merlin engine bells are made on 3D printers. Do you have a cite for that? As usual, Bob is confused. SpaceX uses additive manufacture for the combustion chamber of the SuperDraco engines on Dragon V2 (which is probably where he got "engine bells" from) and for the Main Oxidizer Valve on Merlin engines. The 'printed' valve is more reliable than the cast version that preceded it and cuts manufacturing time by 30x (2 days vice 2 months for the cast article). He's also wrong about them being "built by robotics". While there is some amount of robotic assembly, rocket engines still involve a lot of 'touch labor' during assembly. Perhaps this will also help 'Mayfly' understand why I keep pointing out to him that 'exacting precision' and robotic assembly are at odds with each other: "There’s a lot to see: Rockets, like good suits, are bespoke objects, hand-made to order; a SpaceX tour guide says much of the work is too precise for robotic assembly." https://qz.com/281619/what-it-took-f...space-company/ When you want to do robotic assembly and such, you make parts with more 'meat' on them for the robots to use to attach the parts. Things get heavier. For example, RS-25 engines are expected to gain several hundred pounds as they inject newer automated manufacturing processes and new materials into the design. I've also seen this first hand, although I can't say where. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
#23
|
|||
|
|||
RD-180 relplacement
On Friday, May 12, 2017 at 1:19:44 AM UTC+12, Fred J. McCall wrote:
William Mook wrote: To know the kind of engine you need, you need to know the vehicle it will be used for. To know the kind of vehicle you need, you need to know where it is going and what the vehicle is used for. To know where you are going and what you are doing, you have to have a long-term plan. Is anyone doing this? NASA is not - not officially. China is - officially. * * * Chinese Engines YF-77 (165,000 lbf) http://aviationweek.com/awin/chinese...xceed-saturn-v So a smaller engine than RS-25, BE-4, AR-1, or Raptor. About the size of the Merlin engines that SpaceX builds for use on Falcon. Chinese Vehicles Long-March 11 (140,000 lb LEO) http://www.americaspace.com/2012/07/...g-new-rockets/ Uh, what does that citation have to do with Long March 11? Meant long march 9 obviously. It doesn't even mention it That's because I wrote Long March 11 incorrectly, when I meant to write long march 9. and it's largely about paper rockets. Only because of its date of publication. The YF-77 has flown already on the Long March 5. Long March 11, meanwhile, is about the size of Falcon Heavy. Its largely solid, and is intended mostly for military missions that have long storage times and rapid response requirements. I meant Long March 9, not 11, I miswrote 11 and meant 9. snip speculative MookSpew The only spew is you idiotically focusing on 11 where I obviously meant 9. You got me! It was 9, not 11. Fact is, the core stage of the Long March 9 upper stage can easily replace the solid rocket boosters in the configuration I described - and in tis way exceed SpaceX. Using a common building block to form a 140,000 lb and 400,000 lb launcher from 3 or 7 common components. The Chinese appear to be building modular space habitat and mission module elements, which is what some at NASA wanted to do post-Apollo, but Nixon pulled the plug on that one forcing us down the path of the Space Shuttle. * * * The S-II, the second stage of the Saturn V, weighed 1,090,000 lbs and produced 1,000,000 lbs of thrust with its five J2 engines. Reducing its diameter from 33 ft to 29.2 ft and maintaining its 82 foot length reduces its mass to 781,250 pounds and maintains a 10% structure fraction using similar hardware to that used to recover the SpaceX stages and engines with a 420 sec Isp. Three of these, used as two stages or seven of these used as three stages, would be quite capable, and each one would cost about $60 million to build today. https://history.msfc.nasa.gov/saturn...cond_Stage.pdf This arrangement puts up as much as the system I described previously. Praxair routinely handles vast quantities of liquid hydrogen without a problem. Hydrogen is not the problem NASA and others make it out to be. Nuclear isn't the big bugaboo either. Its 1950s era technology for the USA.. http://www.popularmechanics.com/mili...lear-reactors/ Nuclear thermal and nuclear electric upper stages, that use hydrogen propellant, stored in zero boil off cryogenic tanks are the obvious way forward near term for space travel. The USA had ROVER/NERVA in ground tests and S-II flying in the EARLY 1960s. Its very likely that by 2020s other nations will replicate this capability and build superior configurations with them and by the 2030s do what we should have done in the 1970s. https://en.wikipedia.org/wiki/Saturn_C-5N A reusable S-II stage made into a common core recoverable component and sported a nuclear thermal or nuclear electric deep space stage, would have given us mastery of the solar system in the 1970s and cost less than the Space Shuttle programme. http://www.collectspace.com/ubb/Foru...ML/000880.html http://www.up-ship.com/eAPR/images/v1n2ad5.gif https://en.wikipedia.org/wiki/NERVA#...specifications -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
#24
|
|||
|
|||
RD-180 relplacement
William Mook wrote:
On Friday, May 12, 2017 at 1:19:44 AM UTC+12, Fred J. McCall wrote: William Mook wrote: To know the kind of engine you need, you need to know the vehicle it will be used for. To know the kind of vehicle you need, you need to know where it is going and what the vehicle is used for. To know where you are going and what you are doing, you have to have a long-term plan. Is anyone doing this? NASA is not - not officially. China is - officially. * * * Chinese Engines YF-77 (165,000 lbf) http://aviationweek.com/awin/chinese...xceed-saturn-v So a smaller engine than RS-25, BE-4, AR-1, or Raptor. About the size of the Merlin engines that SpaceX builds for use on Falcon. Chinese Vehicles Long-March 11 (140,000 lb LEO) http://www.americaspace.com/2012/07/...g-new-rockets/ Uh, what does that citation have to do with Long March 11? Meant long march 9 obviously. Not obviously at all. The payload you cite is much to low for Long March 9. It doesn't even mention it That's because I wrote Long March 11 incorrectly, when I meant to write long march 9. And where did you get the payload from? and it's largely about paper rockets. Only because of its date of publication. The YF-77 has flown already on the Long March 5. Long March 9 is a paper rocket. Long March 11, meanwhile, is about the size of Falcon Heavy. Its largely solid, and is intended mostly for military missions that have long storage times and rapid response requirements. I meant Long March 9, not 11, I miswrote 11 and meant 9. And meant a different random payload number? snip speculative MookSpew snip MookSpew -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
#25
|
|||
|
|||
RD-180 relplacement
JF Mezei wrote:
On 2017-05-12 07:07, Jeff Findley wrote: cost models had predicted. Yet we keep soldiering on with SLS/Orion knowing it's costing us 10x what it should. SLS/Orion is pure pork. One side of coin: let industry deal with commoditized launches, while NASA focuses on advancing the state of the art by pushing the limits. And that space of the market is , by definition, not commodity and very expensive. Yet SpaceX ITS has more payload and costs 10% of SLS. (We can argue whether SLS does push the limits and enhances the R&D efforts). However, banning NASA from such "pushing of limits" would be wrong. NASA doesn't do that anymore. Other side of coin: Outfits like SpaceX are doing more R&D and advanacement of spaceflight than NASA, so NASA should get out of the way and just order stuff from commercial. Only side of the coin... -- "Millions for defense, but not one cent for tribute." -- Charles Pinckney |
#26
|
|||
|
|||
RD-180 relplacement
On 17-05-12 20:42 , JF Mezei wrote:
On 2017-05-12 07:15, Jeff Findley wrote: The real problem is that SLS is expenable and always will be. Expendable is a stupid thing for a launch vehicle to be in the 2020s. Question: A LH2/LOX rocket has a positive G force that always pushes the liquid to the bottom of tank during launch. Right ? Is it conceptually possible to fire the engines during free fall to allow the first stage to land? See https://en.wikipedia.org/wiki/Ullage#Rocketry and https://en.wikipedia.org/wiki/Ullage_motor. -- Niklas Holsti Tidorum Ltd niklas holsti tidorum fi . @ . |
#27
|
|||
|
|||
RD-180 relplacement
|
#28
|
|||
|
|||
RD-180 relplacement
|
#29
|
|||
|
|||
RD-180 relplacement
|
#30
|
|||
|
|||
RD-180 relplacement
JF Mezei wrote:
On 2017-05-12 14:55, Fred J. McCall wrote: Yet SpaceX ITS has more payload and costs 10% of SLS. In fairness, SpaceX ITS is vapourware. SLS is hardware (albeit not ready). You obviously don't know the meaning of "vapourware". When you have designs, a schedule (albeit aggressive), and are test firing engines, you're way past 'vapourware'. Yes, SLS is further along. It's also spent twice the entire budget for ITS and isn't done with their initial phase article yet. However, banning NASA from such "pushing of limits" would be wrong. NASA doesn't do that anymore. It should. And? It is institutionally unable to do so. Imagine for a second that they productized SSMEs into a TRULY reusable rocket with enough engines to not need SRBs and which could land itself. Despite higher production cost, wouldn't it becoem commercially viable due to re-usability ? Imagine for a second that they could breed lift demons and thrust demons and not need wings or engines at all. What you're asking for is not that much less preposterous. The shuttle engines lasted far more than 10 flights which is what SpaceX expects its engines to last. If you do almost a total rebuild after every flight, things last a lot longer. That 10 flights is the MINIMUM SpaceX expects their CURRENT engines to last with only inspections required. And have Shuttle engines "lasted far more than 10 flights"? If you really want to go count them up, you can look here for which engines flew on which missions. I started but got bored early. https://science.ksc.nasa.gov/shuttle.../missions.html I did find someone who was keeping track and these are their numbers. Note that most engines are well under 10 flights, with a handful up near 20 flights. Space Shuttle Main Engine Use SN-2005 5 STS-1, STS-2, STS-3, STS-4, STS-5 SN-2006 5 STS-1, STS-2, STS-3, STS-4, STS-5 SN-2007 5 STS-1, STS-2, STS-3, STS-4, STS-5 SN-2011 7 STS-9, STS-51J, STS-61B, STS-33, STS-31, STS-41, STS-50 SN-2012 22 STS-6, STS-7, STS-8, STS-41B, STS-41C, STS-51A, STS-51C, STS-51D, STS-51G, STS-51I, STS-35, STS-43, STS-45, STS-53 STS-60, STS-67, STS-74, STS-79, STS-83, STS-86, STS-90 STS-93 SN-2015 9 STS-6, STS-7, STS-8, STS-41B, STS-61C, STS-40, STS-44, STS-49, STS-52 SN-2017 14 STS-6, STS-7, STS-8, STS-51J, STS-61B, STS-27, STS-49, STS-53, STS-57, STS-61, STS-65, STS-66, STS-70, STS- SN-2018 12 STS-9, STS-41D, STS-51A, STS-51C, STS-51D, STS-51G, STS-51I, STS-61C, STS-54, STS-56, STS-58, STS-59 SN-2019 19 STS-9, STS-51J, STS-61B, STS-26, STS-28, STS-36, STS-38, STS-37, STS-48, STS-50, STS-54, STS-57, STS-61, STS-65 STS-70, STS-76, STS-83, STS-86, STS-93 SN-2020 6 STS-41C, STS-41G, STS-51B, STS-51F, STS-61A, STS-51L SN-2021 6 STS-41D, STS-41G, STS-51B, STS-51F, STS-61A, STS-51L SN-2022 8 STS-26, STS-29, STS-28, STS-32, STS-38, STS-40, STS-42, STS-47 SN-2023 5 STS-41G, STS-51B, STS-51F, STS-61A, STS-51L SN-2024 7 STS-32, STS-35, STS-43, STS-45, STS-53, STS-56, STS-58 SN-2026 6 STS-39, STS-42, STS-47, STS-68, STS-74, STS-80 SN-2027 7 STS-30, STS-34, STS-36, STS-38, STS-40, STS-42, STS-46 SN-2028 11 STS-26, STS-29, STS-28, STS-32, STS-35, STS-43, STS-45, STS-59, STS-68, STS-71, STS-72 SN-2029 15 STS-27, STS-30, STS-34, STS-39, STS-44, STS-47, STS-55, STS-51, STS-62, STS-64, STS-63, STS-69, STS-75, STS-80, STS-84 SN-2030 10 STS-27, STS-30, STS-34, STS-36, STS-39, STS-44, STS-49, STS-52, STS-65, STS-66 SN-2031 17 STS-29, STS-33, STS-31, STS-41, STS-37, STS-48, STS-50, STS-55, STS-51, STS-62, STS-64, STS-67, STS-73, STS-79, STS-84, STS-87, STS-93 SN-2032 7 STS-46, STS-60, STS-71, STS-74, STS-80, STS-84, STS-90 SN-2033 9 STS-46, STS-54, STS-56, STS-61, STS-59, STS-68, STS-67, STS-79, STS-94 SN-2034 9 STS-52, STS-57, STS-51, STS-60, STS-66, STS-71, STS-75, STS-81, STS-94 SN-2035 3 STS-63, STS-69, STS-76 SN-2036 3 STS-70, STS-72, STS-78 SN-2037 5 STS-73, STS-77, STS-82, STS-94, STS-87 SN-2038 3 STS-73, STS-77, STS-82 SN-2039 4 STS-72, STS-78, STS-85, STS-87 SN-2040 4 STS-77, STS-82, STS-86, STS-91 SN-2041 5 STS-78, STS-81, STS-85, STS-90, STS-88 SN-2042 3 STS-81, STS-85, STS-91 SN-2043 7 STS-89, STS-95, STS-103, STS-101, STS-97, STS-100, STS-108 SN-2044 7 STS-89, STS-88, STS-99, STS-106, STS-98, STS-105, STS-111 SN-2045 8 STS-89, STS-95, STS-92, STS-102, STS-105, STS-110, STS-113, STS-121 SN-2047 6 STS-91, STS-96, STS-106, STS-98, STS-104, STS-109 SN-2048 4 STS-95, STS-92, STS-110, STS-112 SN-2049 7 STS-96, STS-103, STS-101, STS-97, STS-100, STS-108, STS-107 SN-2050 5 STS-88, STS-99, STS-108, STS-111, STS-113 SN-2051 4 STS-96, STS-104, STS-110, STS-112 SN-2052 5 STS-99, STS-106, STS-98, STS-105, STS-121 SN-2053 5 STS-103, STS-92, STS-102, STS-109, STS-107 SN-2054 6 STS-101, STS-97, STS-100, STS-111, STS-114, STS-121 SN-2055 1 STS-112 SN-2056 6 STS-102, STS-104, STS-109, STS-113, STS-107, STS-114 SN-2057 1 STS-114 SN-2107 5 STS-33, STS-31, STS-41, STS-37, STS-48 SN-2109 17 STS-41B, STS-41C, STS-41D, STS-51A, STS-51C, STS-51D, STS-51G, STS-51I, STS-61C, STS-55, STS-58, STS-62, STS-64, STS-63, STS-69, STS-76, STS-83 Look at aviation: the 777 won over the 747 because it has 2 expensive engines instead of 4 medium price engines. Maintenance becomes a huge issue for cost savings when you have half the number of engines to inspect/maintain in your fleet. No, that's not why it 'won'. It 'won' because it costs less to OPERATE, not because it costs less to BUY. Imagine if SSMEs were truly re-usable and you could launch to space with half the number of engines needed by SpaceX, Imagine Dragons. Imagine unicorns ****ting magic pixie dust. Now look at the actual numbers. For reusability to matter you have to have a way to get the engines back. For SSME that way was attaching them to a Space Shuttle. SLS has no way to return engines. If you put that in, you're adding weight and reducing performance. But let's pretend you aren't. If you're not going to use solids, you need to get another 7.2 million pounds of thrust from somewhere. That means you're going from 4 SSMEs to 22 of them for a total thrust of just under 9.2 million pounds of thrust (vice 8.87 million pounds of thrust for the current vehicle). That's for Phase 1 SLS with a payload of around 70 tonnes to LEO and we're not counting the engine in the upper stage. Now look at Falcon Heavy. With 27 engines in the first stage vice 24 of the much more expensive RS-25 engines, you get a payload about 90% that of SLS Block 1B. SSMEs are much more expensive engines. An RS-25 engined vehicle is never going to be able to compete economically, no matter what magic you assume happens. Assume each vehicle will lose around 15% of the performance I've described if flown 'recoverable'. At the end of the day, the "heavy lift" will be used to LEO to assemble and fuel what goes to Mars. Politicially uninteresting to fund a replacement for the shuttle that is limited to LEO. But that is a necessary building block for the Mars expedition ship. If you're talking about Mars, ITS uses about twice as many Raptor engines on its first stage as your magic reusable SLS (42 vice 22) but also has almost eight times the payload. And ITS is already designed for full reusability. It all comes down to economics. If Rocketdyne were told it would compete against SpaceX for lifting cargo to LEO, how much more cost efficient would production of SSME/RS25 become ? It wouldn't. AJR doesn't design boosters. They build engines. As long as SSMEs remain in PORK territory, Rocketdyne has no incentive to compete. It just gets money to deliver 6 engines at some fat price and doesn't care about a commercial market for those engines. And if SSMEs don't remain in PORK territory, AJR has no incentive to build engines because they cannot compete. With proper incentives, perha]s Rocketdyne can do something with SSMEs, or perhaps the economics are TRULY not good and the SpaceX "many small engines" economics are better. But unless Rocketdyne is given incentive to compete, we'll never really know if the RS25 could be manufacturerd at much lower price that makes it competitive (or same ballpark at least). There is no market for the RS-25 other than SLS. There is no market for R-1 unless BE-4 is a magnificent failure (unlikely) and AJR wouldn't be developing it without government funding. You see, AJR doesn't have a billionaire funding it, so they have to make all their money as they go and can't sink billions into developing engines with no market for them. -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
Thread Tools | |
Display Modes | |
|
|