Quote from: RocketmanUS on 03/20/2013 12:50 amUse RD-180's.That's called Atlas Phase 2, and it's nowhere near as powerful.
Use RD-180's.
And why should we use Russian engines when we have several perfectly good ones of our own?
No, your point is baseless.RS-68 manrating mods are known and were going to be used for SLSIt doesn't take much to manrate the vehicleDelta launch site only needs a crew access towerP.S. Delta doesn't have a mobile launcher
Quote from: 93143 on 03/20/2013 01:19 amQuote from: RocketmanUS on 03/20/2013 12:50 amUse RD-180's.That's called Atlas Phase 2, and it's nowhere near as powerful.(4) RD-180's with a 5.4m diameter stage.Quote from: llanitedave on 03/20/2013 01:21 amAnd why should we use Russian engines when we have several perfectly good ones of our own?What engines in production that do not need to be modified?I'm looking at less development cost and less time till a possible first flight.Yes I would have preferred an American made engine.
Quote from: RocketmanUS on 03/20/2013 01:27 amQuote from: 93143 on 03/20/2013 01:19 amQuote from: RocketmanUS on 03/20/2013 12:50 amUse RD-180's.That's called Atlas Phase 2, and it's nowhere near as powerful.(4) RD-180's with a 5.4m diameter stage.Quote from: llanitedave on 03/20/2013 01:21 amAnd why should we use Russian engines when we have several perfectly good ones of our own?What engines in production that do not need to be modified?I'm looking at less development cost and less time till a possible first flight.Yes I would have preferred an American made engine.How is switching SLS to a different core and a different engine, especially at this stage of the design, going to reduce development time?
Quote from: llanitedave on 03/20/2013 01:21 amAnd why should we use Russian engines when we have several perfectly good ones of our own?What engines in production that do not need to be modified?
How would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?
Quote from: llanitedave on 03/20/2013 02:42 amQuote from: RocketmanUS on 03/20/2013 01:27 amQuote from: 93143 on 03/20/2013 01:19 amQuote from: RocketmanUS on 03/20/2013 12:50 amUse RD-180's.That's called Atlas Phase 2, and it's nowhere near as powerful.(4) RD-180's with a 5.4m diameter stage.Quote from: llanitedave on 03/20/2013 01:21 amAnd why should we use Russian engines when we have several perfectly good ones of our own?What engines in production that do not need to be modified?I'm looking at less development cost and less time till a possible first flight.Yes I would have preferred an American made engine.How is switching SLS to a different core and a different engine, especially at this stage of the design, going to reduce development time?No, and you didn't answer the question ( What engines in production that do not need to be modified? ).If they are going to have the LRB's , then let's have them now and not use the 5 seg SRB's. And if they do go with the LRB's then commercial could use it as a 1st stage for a single stick. If for some reason SLS were canceled then the single stick with common core ( tri-core ) could be a HLV ( back up plan and would not have to restart production of the costly SSME's ).With the already in production and well proven with great specs RD-180's four of them on each booster would get us at least the 130mt that is required for block II. They could be ready by the wanted 2017 launch and the core made for them.
Quote from: Jim on 03/19/2013 08:33 pmNo, your point is baseless.RS-68 manrating mods are known and were going to be used for SLSIt doesn't take much to manrate the vehicleDelta launch site only needs a crew access towerP.S. Delta doesn't have a mobile launcherDon't take it personally big guy, it's okay to disagree....whats your source...
Don't take him personally either. He comes across that way to everybody. He's to the point and does not use any extra words.He is a source. He works for NASA. He is a rocket scientist. He is smarter than most of us put together. He's virtually never wrong.
Though you could use Falcon 9 cores as boosters.
We already have RS25D's in stock, ready to go. That's what the core is already designed around, and that's what will work. That gives us plenty of time to complete follow-on engines if we wish, whether J2-X, which is essentially complete, F1B, which has had the bulk of development work already done via previous iterations, or the RS25-E, which is a fairly minor modification to the current version.If all you're talking about is replacing the SRB's with RD-180 LRB's, there's no need for that "right now". We wouldn't be saving any money by tossing out the SRB segments we already have, nor for making a crash program to go to 130 tons of lift when payload development has barely even been considered.The key word of this thread is "evolve". Let's get the basic system going, spend the money to make the core operational, and then start shunting money into payload development that will justify the 130 ton vehicle. That way the true heavy lift capacity and the truly heavy payloads will both be ready in closer to the same time frame.
If the RD-180 were US-built would Energomash make any profit on those engines? Depending on how the contracts were written this might happen via royalties paid to Energomash or via Energomash's partial ownership of RD AMROSS. If so I could see a nationalism problem for US-built RD-180s.
Quote from: deltaV on 03/20/2013 03:19 pmIf the RD-180 were US-built would Energomash make any profit on those engines? Depending on how the contracts were written this might happen via royalties paid to Energomash or via Energomash's partial ownership of RD AMROSS. If so I could see a nationalism problem for US-built RD-180s.I think it depends on how it's done. Top secret US government satillites are launched on Russian engines with Atlas. But that's the LV ULA provides, so it's seen as a government payload launching on a commercial rocket. If NASA builds the rocket with Russian engines, then maybe there's a perception problem. But if NASA buys rocket boosters from some company, and they have RD-180's on them, is the "NASA launching on Russian engines"? Or NASA launching on a ULA made "Super-Atlas V" rocket?And PWR can always transition to making the RD-180's themselvs if there was a business case to do so. I believe they bought the liscence to do that. And make other engines in the family, like the RD-171.
RS-68 manrating mods are known and were going to be used for SLS
Quote from: davey142 on 03/20/2013 10:55 amHow would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?Wouldn't Congress by OK with it if an American company were to build RD-180s in the US?
Quote from: RocketmanUS on 03/20/2013 04:46 amQuote from: llanitedave on 03/20/2013 02:42 amQuote from: RocketmanUS on 03/20/2013 01:27 amQuote from: 93143 on 03/20/2013 01:19 amQuote from: RocketmanUS on 03/20/2013 12:50 amUse RD-180's.That's called Atlas Phase 2, and it's nowhere near as powerful.(4) RD-180's with a 5.4m diameter stage.Quote from: llanitedave on 03/20/2013 01:21 amAnd why should we use Russian engines when we have several perfectly good ones of our own?What engines in production that do not need to be modified?I'm looking at less development cost and less time till a possible first flight.Yes I would have preferred an American made engine.How is switching SLS to a different core and a different engine, especially at this stage of the design, going to reduce development time?No, and you didn't answer the question ( What engines in production that do not need to be modified? ).If they are going to have the LRB's , then let's have them now and not use the 5 seg SRB's. And if they do go with the LRB's then commercial could use it as a 1st stage for a single stick. If for some reason SLS were canceled then the single stick with common core ( tri-core ) could be a HLV ( back up plan and would not have to restart production of the costly SSME's ).With the already in production and well proven with great specs RD-180's four of them on each booster would get us at least the 130mt that is required for block II. They could be ready by the wanted 2017 launch and the core made for them.We already have RS25D's in stock, ready to go. That's what the core is already designed around, and that's what will work. That gives us plenty of time to complete follow-on engines if we wish, whether J2-X, which is essentially complete, F1B, which has had the bulk of development work already done via previous iterations, or the RS25-E, which is a fairly minor modification to the current version.If all you're talking about is replacing the SRB's with RD-180 LRB's, there's no need for that "right now". We wouldn't be saving any money by tossing out the SRB segments we already have, nor for making a crash program to go to 130 tons of lift when payload development has barely even been considered.The key word of this thread is "evolve". Let's get the basic system going, spend the money to make the core operational, and then start shunting money into payload development that will justify the 130 ton vehicle. That way the true heavy lift capacity and the truly heavy payloads will both be ready in closer to the same time frame.
Quote from: deltaV on 03/20/2013 02:28 pmQuote from: davey142 on 03/20/2013 10:55 amHow would NASA convince congress (especially the Senate) to allow them to use a foreign engine, especially one from Russia?Wouldn't Congress by OK with it if an American company were to build RD-180s in the US?Wouldn't that negate any cost savings for the RD-180? SLS can't afford any increased cost, especially changing an engine midway through the design. Using them for LRBs could work if an American company modifies them just enough to make it an American derivative, but that means more money!