However, I agree that once BFR is flying or perhaps even when it's late into development and looking "inevitable" with metal being bent and Raptor firing properly...that SLS main supporting argument that it's the only LV with that capacity, and that capacity is necessary for BLEO HSF pretty much goes away. Then I think it'll be cancelled after just a few launches...
Off-the-wall thought - SpaceX take up BE-4 instead of developing Raptor.cheers, Martin
Quote from: Lobo on 03/02/2015 07:30 pmHowever, I agree that once BFR is flying or perhaps even when it's late into development and looking "inevitable" with metal being bent and Raptor firing properly...that SLS main supporting argument that it's the only LV with that capacity, and that capacity is necessary for BLEO HSF pretty much goes away. Then I think it'll be cancelled after just a few launches...One would think so. But then again there's that little cadre of senators holding committee chairmanships. I think your scenario will happen if they're retired by then. If they all pull a Strom Thurmond and stay until they're centenarians, SLS may well continue receiving its welfare payments.
Quote from: Lars-J on 03/02/2015 06:36 pmQuote from: brovane on 03/02/2015 06:27 pmTwo 500,000 lbf Raptors could be a replacement for the RD-180 on the Atlas-V. I guess you missed the BE-4 announcement. Off-the-wall thought - SpaceX take up BE-4 instead of developing Raptor.cheers, Martin
Quote from: brovane on 03/02/2015 06:27 pmTwo 500,000 lbf Raptors could be a replacement for the RD-180 on the Atlas-V. I guess you missed the BE-4 announcement.
Two 500,000 lbf Raptors could be a replacement for the RD-180 on the Atlas-V.
Quote from: Lars-J on 03/02/2015 06:36 pmQuote from: brovane on 03/02/2015 06:27 pmQuote from: BobHk on 03/02/2015 05:52 pmQuote from: spacenut on 03/02/2015 04:52 pmDoes anyone know what is happening here? Wikipedia said they upgraded the metholox engine to 1 million lbs thrust and speculation is for a 10m rocket with 9 of these engines for 9 million lbs thrust. This update said February 2015. Also does anyone have a time frame for this to come about? Would it be before SLS is ready?In a recent reddit appearance Musk said they're downsizing Raptor to 500,000 lbf I don't bet against SpaceX producing anything as quickly as they want to. Two 500,000 lbf Raptors could be a replacement for the RD-180 on the Atlas-V. I guess you missed the BE-4 announcement. Off-the-wall thought - SpaceX take up BE-4 instead of developing Raptor.cheers, Martin
Quote from: brovane on 03/02/2015 06:27 pmQuote from: BobHk on 03/02/2015 05:52 pmQuote from: spacenut on 03/02/2015 04:52 pmDoes anyone know what is happening here? Wikipedia said they upgraded the metholox engine to 1 million lbs thrust and speculation is for a 10m rocket with 9 of these engines for 9 million lbs thrust. This update said February 2015. Also does anyone have a time frame for this to come about? Would it be before SLS is ready?In a recent reddit appearance Musk said they're downsizing Raptor to 500,000 lbf I don't bet against SpaceX producing anything as quickly as they want to. Two 500,000 lbf Raptors could be a replacement for the RD-180 on the Atlas-V. I guess you missed the BE-4 announcement.
Quote from: BobHk on 03/02/2015 05:52 pmQuote from: spacenut on 03/02/2015 04:52 pmDoes anyone know what is happening here? Wikipedia said they upgraded the metholox engine to 1 million lbs thrust and speculation is for a 10m rocket with 9 of these engines for 9 million lbs thrust. This update said February 2015. Also does anyone have a time frame for this to come about? Would it be before SLS is ready?In a recent reddit appearance Musk said they're downsizing Raptor to 500,000 lbf I don't bet against SpaceX producing anything as quickly as they want to. Two 500,000 lbf Raptors could be a replacement for the RD-180 on the Atlas-V.
Quote from: spacenut on 03/02/2015 04:52 pmDoes anyone know what is happening here? Wikipedia said they upgraded the metholox engine to 1 million lbs thrust and speculation is for a 10m rocket with 9 of these engines for 9 million lbs thrust. This update said February 2015. Also does anyone have a time frame for this to come about? Would it be before SLS is ready?In a recent reddit appearance Musk said they're downsizing Raptor to 500,000 lbf I don't bet against SpaceX producing anything as quickly as they want to.
Does anyone know what is happening here? Wikipedia said they upgraded the metholox engine to 1 million lbs thrust and speculation is for a 10m rocket with 9 of these engines for 9 million lbs thrust. This update said February 2015. Also does anyone have a time frame for this to come about? Would it be before SLS is ready?
Wouldn't it be ironic if SpaceX's Raptor-powered rocket led to SLS being cancelled, which led to the same bigger-is-better logic being applied to, say, a 500 ton to LEO NASA rocket that costs even more?
Quote from: kch on 03/02/2015 08:13 pmQuote from: symbios on 03/02/2015 07:54 pmQuote from: kch on 03/02/2015 07:49 pmQuote from: Lobo on 03/02/2015 07:30 pmWithout SLS, NASA BLEO HSF will pretty much be locked into SpaceX. ... which is pretty much where NASA LEO HSF is now with regard to the Russians -- why would they make *that* mistake again? That's more than enough reason to continue SLS, even if SpaceX gave them a dozen free BFR flights. No more "barrels and ankles" situations, thank-you-very-much!So you are saying that the Geopolitical situation between SpaceX and America is going to deteriorate because of Elon Musks overwhelming ambition to conquer other nations? And this will cause Elon Musk to tell America to find a trampoline? Yea that will happen... [/sarcasm]LMAO ... no. Nice try, but no. Once NASA is "over a barrel" (wrt Russia, or SpaceX, or *any* potential-monopoly supplier), the price goes up....... up higher even than NASA's own SLS pricing? That's a lot of up.
Quote from: symbios on 03/02/2015 07:54 pmQuote from: kch on 03/02/2015 07:49 pmQuote from: Lobo on 03/02/2015 07:30 pmWithout SLS, NASA BLEO HSF will pretty much be locked into SpaceX. ... which is pretty much where NASA LEO HSF is now with regard to the Russians -- why would they make *that* mistake again? That's more than enough reason to continue SLS, even if SpaceX gave them a dozen free BFR flights. No more "barrels and ankles" situations, thank-you-very-much!So you are saying that the Geopolitical situation between SpaceX and America is going to deteriorate because of Elon Musks overwhelming ambition to conquer other nations? And this will cause Elon Musk to tell America to find a trampoline? Yea that will happen... [/sarcasm]LMAO ... no. Nice try, but no. Once NASA is "over a barrel" (wrt Russia, or SpaceX, or *any* potential-monopoly supplier), the price goes up....
Quote from: kch on 03/02/2015 07:49 pmQuote from: Lobo on 03/02/2015 07:30 pmWithout SLS, NASA BLEO HSF will pretty much be locked into SpaceX. ... which is pretty much where NASA LEO HSF is now with regard to the Russians -- why would they make *that* mistake again? That's more than enough reason to continue SLS, even if SpaceX gave them a dozen free BFR flights. No more "barrels and ankles" situations, thank-you-very-much!So you are saying that the Geopolitical situation between SpaceX and America is going to deteriorate because of Elon Musks overwhelming ambition to conquer other nations? And this will cause Elon Musk to tell America to find a trampoline? Yea that will happen... [/sarcasm]
Quote from: Lobo on 03/02/2015 07:30 pmWithout SLS, NASA BLEO HSF will pretty much be locked into SpaceX. ... which is pretty much where NASA LEO HSF is now with regard to the Russians -- why would they make *that* mistake again? That's more than enough reason to continue SLS, even if SpaceX gave them a dozen free BFR flights. No more "barrels and ankles" situations, thank-you-very-much!
Without SLS, NASA BLEO HSF will pretty much be locked into SpaceX.
There are laws preventing ripping off the government. Doesn't mean costs don't grow, but it will not exceed SLS.
The one thing to bring into consideration is that unlike all the other scenarios, SpaceX's own plans are much larger than any that the government has in mind.If NASA says "never mind SLS, we'll fly with BFR" it won't make much difference to BFR, financially. However, SpaceX will be more than happy to gain from NASA's other resources, and given SpaceX's plan, there's a large multiplier there.So it's in their interest to serve as the heavy lift provider for NASA, and not in their interest to jack up pricing the minute they can. They are not a near-sighted company.
Or SpaceX gets the USAF contract to develop a new engine that Congress wants in addition to the BE-4. The USAF pays to finish the development of a Raptor engine in the range of 500-600k lbf. SpaceX gets one part of the US govt to pay to develop the engine for it's BFR and it can then have a rival HLV to NASA's SLS.
And its not hard to see this actually, BFR as a design is much better than SLS and less complex purely from a technical standpoint. The single biggest advantage is the methane fuel supply instead of LH2.
Potentially worth noting here. MCT (unless I am mistaken) which we often refer to as BFR is (as designed I think) more powerful than SLS. Even with the advanced booster, an extra RS25 (5 engine core) and a j2x upper stage (which is shelved at present) I believe SLS even in Block 3 territory only gets up around what, 150 mt? maybe? If the numbers are right on BFR it likely would be that powerful in its block one design. Engine improvements, iterative design improvements, could make it even stronger. And its not hard to see this actually, BFR as a design is much better than SLS and less complex purely from a technical standpoint. The single biggest advantage is the methane fuel supply instead of LH2. Methane is extremely energetic as a fuel, there is a massive surplus of it worldwide at present (gas wells are shut in due to over production) so its very VERY cheap to get, compared to LH2 which is quite expansive, and it should have more reaction mass per kg for a from sea level launch. Therefore you can, in theory, get more power out of a methane engine than both RP1 and LH2. For in vacuum flight, and this depends highly on engine design, its theoretically possible to get a greater ISP out of it than a comparable LH2 engine, purely due to the reason that some of your engine and tank-age components do not need to be quite as hardy when dealing with liquid methane, due to temperature constraints. Correct me if I am wrong but I believe LH2 is significantly colder than liquid methane. In any case much of this is either in the design or theoretical realm right now as none of these things have been tried yet, let alone for a full flow stage combustion configuration, I don't believe anyone has ever tried that with a methalox engine. But the potential gains here are enormous, I think you can easily make something more powerful than most of the SLS designs in your first go around and potentially more reliable as well, and I am a shuttle and shuttle hardware lover saying that.
The cost of the fuel itself is a rounding error in the cost of launch of such a large rocket. Also,you're also confusing natural gas and methane. Natural gas is what comes out of the ground and it's not pure methane, it needs to be processed to be methane. The cost savings come from ease of ground handling, not the cost of the fuel.
You then state that you have more reaction mass per kilogram, which is incorrect as, mass is mass, there is no way to make 1kg less than 1kg in a chemical reaction. Perhaps you meant with increased tankage mass for the less dense hydrogen fuel that you mention a little later? Please clarify.
If you build an engine poorly you could get worse ISP out of an ion motor than an Estes model rocket motor. I'm unsure of the point you're trying to make. The upper bound is dictated by reactant chemical energy, which is higher with LH2 than with CH4. If you're talking impulse density factoring in tankage it's a muddier topic. I don't mean to pick on you, I just hope you'll write with a little more specificity in the future so I, and others, aren't tempted to tear into you for inaccuracies.
The only full flow engine demonstrated was the RD-280 and managed 301s ISP from hypergols. AJR was working on the power-head but I don't know if they ever had a working model.
This is what I think may happen. SpaceX builds an 8m core rocket with about 5-5.5 million lb thrust which can deliver about 75 tons to LEO (next step up from F9H + wider loads). A three core heavy version of the 8m rocket might deliver 200+ tons to LEO. This trumps SLS and gives a smaller more usable single core rocket for deep space probes greater than F9H can deliver. Now he might build a 25 engine 10m core to do it all at once. I think it would be more flexible with the smaller core.