• Mr Snarky Answer

    Probably not. Lots of additional cost to muck with the GSE/TEL second stage on FH for virtually no demand. Especially now that they’ve demonstrated long duration cold soak / coast on MerlinVac

  • Vladislaw

    “Skylon promised literal aircraft turnaround ability, something even SX really won’t ever be able to do in the near term. ”

    You can not take a promise to the bank. SpaceX is actually making bank and will make BILLIONS before skylon ever flies.

  • Vladislaw

    You have to be more specific. I am from North Dakota, we only have two seasons, winter and the 4th of July.

  • Vladislaw

    Isn’t that how he did falcon 9? Tested the core .. launched some dead weight .. and then finally did the capsule?

  • Vladislaw

    Have you ever seen any numbers yet of what Blue Origin is planning after new Glenn? The New Armstrong?

  • Richard Malcolm

    Given the two months they need to prep LC-39A…add a little of the usual buffer…I think you need to be looking at October/November time frame. Assuming no more hitches develop.

    Probably a safe bet to expect it to fly before Thanksgiving.

  • JamesG

    That is true. Although the Reaction Engines guys got quite a bit from banks and guberment for their promise. They’ve been making a living tinkering with it for what? A decade now?

  • JamesG

    Haven’t bothered to look. Blue needs to have actually put something into orbit before I’m going to take them serious about NA.

  • JamesG

    I think because NASA told/paid him to. They were trying to launch paying customers from the first Falcon-1.

  • Paul451

    However, she never specifically said “scaled”. We still don’t know if she meant a full-sized but limited-thrust test unit, or a physically smaller test unit. The former would be consistent with their development of Merlin engines, the latter not so much.

    [The Merlin 1A produced 340 kN. Merlin 1D started with 620kN and is now up around 845kN. (Sea-level figures.) I find it amusing that the maximum thrust of the 1A is now the minimum thrust the 1D can be throttled to. 40%]

  • delphinus100

    As long as there’s an adequate market for Skylon (or any other launcher) when it’s ready, who makes BILLIONS *first* is irrelevant…

  • Mr Snarky Answer

    It is all over NSF that this is a 1/3 scale Raptor. Some components could be full scale and others sub-scale. For instance they could build a full scale power-pack and put it on a sub-scale chamber and nozzle for lower power level testing But it has been settled for months that the Raptor(s) being tested are not 100% scale in all attributes.

  • Paul451

    it has been settled for months

    {laughs} The entire NSF speculation is based solely on Shotwell’s throw-away comment. (Which is not unusual for NSF.)

    Raptor is roughly the same physical size as Merlin. It uses the much higher chamber pressure to (eventually) achieve >3 times the thrust as Merlin. Musk (in his presentation last year) talked about how this is to allow it to fit with the existing production and testing systems.

    The idea that Raptor is physically “1/3 scale” means creating an entire new production and testing system to that scale, all for one demonstrator engine.

    How does that possibly make sense to you?

  • Mr Snarky Answer

    The nozzle is clearly sub-scale from the photography to start out with. And they aren’t the first, RS-25 was first tested with sub-scale nozzle limiting to 30% power level while they worked out startup issues for year using the so called “bobtail” nozzle, same was for J2X testing.

    I certainly could make a case for working with a sub-scale nozzle and chamber to get a feel for the startup of the power-head at limited power levels and an idea if your LOX rich pre-burner metallurgy is on track before ramping up. These are one/two off development engines there is no production line, genius. Also FFSC engines scale a lot more easily since the pumps are not driven by a common shaft. Remember Raptor was going to be a giant 1+ million pound thrust mega engine at one point…you think they would that engine in one shot?

    I can’t say it better than Alejandro G. Belluscio who sourced his article on L2 contacts.

    “Since the final thrust level of the Raptor had not been settled, it was decided that the first integrated test engine would be a 1MN sub-scale engine.

    It enabled the full testing at Stennis E2 and allowed for the development of robust startup and shutdown sequences, characterize hardware durability and anchor analytical models that would be used for future designs.”

  • Kenneth_Brown

    Some noise restrictions have been imposed at SpaceX’s Texas facility and they may not be able to test all three engine sets at once.

  • Paul451

    I certainly could make a case for working with a sub-scale nozzle and chamber

    Nozzle, yes. But combustion chamber no. Their entire modelling of the combustion process will be based on the full size of the Raptor. It makes no sense to develop a smaller chamber for a one-off test that can’t validate that model.

    These are one/two off development engines there is no production line, genius.

    And I didn’t say “production line”, dickhole.

  • Mr Snarky Answer

    So a sub-scale nozzle and sub-scale power-head on a “full size” chamber would not be a sub-scaled engine? And totally plausible given limitations of injector testing at Stennis E2 stand mentioned in the article. Geez

  • Paul451

    And where did I say “sub-scale powerhead”?

    Re: Sub-scale nozzle. The images from Stennis and McGregor show that the demonstrator doesn’t have a full nozzle. Which is not unusual in early tests, just a short cone beyond to combustion chamber to provide the correct back pressure to the combustion chamber. Such pseudo-nozzles are not “sub-scale nozzles” in the sense that you would ever use them on a flight engine.

  • Paul451

    I’m not even sure there’s been enough information to know whether NA is their next launcher after NG, or if it’s the lunar infrastructure that flies on NG.

    Or whether it’s anything at all except a joke tweet from Bezos.

    (Similar to Musk talking about future Mars rockets making ITS look small.)

  • Mr Snarky Answer

    You didn’t, the well researched article did.

    They didn’t do any full-up testing at Stennis so there was no nozzle to test (Your point being bogus). The “full testing” he is referring to is for the pre-burners and injector, they did do injector and pre-burner testing there. And according to the article they were limited in scale which drove sub-scale nature of the development engine along with the final power level being a moving target. They wanted to build a powerhead that was the same size as the testing at Stennis E2 components. Raptor was originally classed much higher than 650K pounds and then dropped lower and back up to 650K. All during this time they have a development engine under design/production. Hmmm makes you wonder….oh no it doesn’t. You are shooting for the hip here and apparently have no concept of the detailed history of this development.

    “Once the final engine thrust was defined, the engine could be scaled up with relative ease. The full flow cycle is very helpful in that sense and the 1MN thrust level would already be considered a big engine.

    With the production engines – as currently envisioned – it would need to triple its thrust. Not trivial, but still within what could be considered highly representative as a demonstrator.”

    So I have a highly researched article that is confirmed by SpaceX employees on NSF L2 or do I go with Paul the pharmacist this time? (reference to Curb Your Enthusiasm if it was lost on you). I’ll stick with the doctor, thanks.

  • Paul451

    The LH2 system stays on the ground

    No, it radically alters the launch vehicle as well.

    or spend more for a bigger vehicle.

    Because of the lower density, LH first stages are always bigger for the same payload.

  • JamesG

    Maybe worth it if you want to use the same propellants and engine family in the entire vehicle. It becomes less an engineering question than an economic one.

  • Michael Vaicaitis

    The main design driver of Skylon is to be SSTO, because it was thought that SSTO was the only way to achieve reusability. SpaceX (and BO) are currently proving that notion to be incorrect. Skylon is unlikely to be ready much before 2030, by which time fully VTVL will have permanently eaten most of its “adequate market”. Also, Skylon is only able to lift 12 tonnes to LEO (launched from the Cape, 15 tonnes equatorial).

  • Michael Vaicaitis

    The breakthrough that makes SABRE/Skylon possible is the heat exchanger. They have already designed and proved this and there are other potential markets for that technology. So, the funding to date is based on an innovation that actually exists, not on a promise.

  • Kapitalist

    Reusability means that mass doesn’t matter. That’s the most profound paradigm shift in rocketry since Tsialkovsky’s rocket equation a hundred years ago. The larger the launchers the cheaper the transport. The rocket itself costs nothing when its manufacturing cost can be divided by X launches. Ships and airplanes are the best analogues since they don’t need rails or roads just ports, and they have grown alot and become so very cheap that it doesn’t matter from where in the world you import anything.

  • duheagle

    Hydrolox is only “top shelf” at the top of the atmosphere and above. Launching from sea level with Hydrolox gives away most of its vacuum Isp advantage over other propellants.