23 thoughts on “The RD-180 Replacement”

  1. Yeah it seems to make little sense. But reading between the lines I suspect this is due to the confluence of a couple of factors.

    One is that Aerojet-Rocketdyne is being boned here. Remember that RD-AMROSS (Rocketdyne joint venture) were the ones importing the RD-180s and the RS-68 used to power the Delta IV. They had a hand on every single main propulsion engine around but now they will be dropped like a rock if we continue with the current course. Sure there is SLS. If it becomes available. Plus the amount of engines to manufacture for that project, if it becomes available, will be minimal. This leaves them at best with the RL-10 as a bread earner and even that is in jeopardy.

    The other is that some people in the USAF and the companies which compose ULA (probably not ULA per se) might not be terribly fond of a market where all the viable engines are being produced by competitors. Both SpaceX and Blue Origin either do or want to do launches and launch vehicles. If Aerojet-Rocketdyne does not subsist there will be no pure play rocket propulsion company left these guys (Boeing, Lockheed-Martin, etc) can use.

    1. The RS-68 is imported? I thought it was a home-grown engine, based on Russian design ideas, but it is imported?

      2. I guess I wasn’t clear enough. The RD-180 is the one that is imported by their joint venture. The RS-68 is designed and manufactured by Rocketdyne now Aerojet-Rocketdyne.

  2. Last but not least there is a chance that Blue Origin could fail with BE-4 and the companies which compose ULA want insurance in case that happens. Preferably insurance that doesn’t cost them anything.

  3. Maybe the Air Force could track down the company that built the RP-1/LOX fueled RS-56 for the Atlas II and see if they could build more of them. They surely still have the company’s business card or an old phone number or something.

  4. Frankly, after the F22, A-10, and nuclear weapons handling fiascos, I doubt sincerely that I’d be paying much attention to what the Air Force says it wants.

    1. I think you mean F-35. If anything’s wrong with the Raptor, it’s that there aren’t 300 of them like they originally wanted.

  5. “Congress mandated last year that the Defense Department develop a kerosene-fueled main rocket engine to replace the RD-180, also kerosene fueled, by 2019. While Air Force officials have raised doubts they can meet that deadline — Hyten called it an “enormous” technological challenge — service leaders have nonetheless been working for months on an acquisition strategy.”

    From today to the December 31, 2019: 1,738 days
    From September 8, 2005 (SpaceX announces it will develop Falcon 9) to June 4, 2010 (Falcon 9 first flight): 1,699 days.

    How can developing one single engine be such an enormous task that officials of the United States government doubt they can do it within a greater amount of time than a relatively small private company took to develop an engine and a launch vehicle, and fly them both? What is wrong with this country?

    1. Gotta have some margin in there. We can’t get too vocally ambitious. What if we fail to meet schedule? We could get blamed! That could potentially be a Career Limiting Move if it doesn’t pan out and we can’t put the responsibility on the next guy to PCS to this job.

      Besides, the longer it takes, the more likely Congress will get bored with funding it and become distracted by the next slightly different new shiny, and then we can act disappointed but dutiful as the sunk cost of hundreds o’millions gets forgotten and we execute the next hundred o’million on the new shiny, ingratiating us with this new crop o’Congresscritters. Who have a say if we pin on (more) stars.

      Lets be pragmatic.

    2. Falcon 9 initially used the same engine as Falcon 1. It usually takes 5 years to develop a new engine. Although Merlin-1D seems to have taken a lot shorter time than usual.

      1. Okay, SpaceX was incorporated in June 2002. Let’s say June 30, 2002. Falcon 1 was launched on March 24, 2004. 1,363 days elapsed. The engine was certainly developed, and they flew the vehicle, albeit unsuccessfully.

        So the actual engine development took 336 days less than what SpaceX took to develop the F9. I think that actually amplifies my argument immensely.

        1. It’s more complicated than that. The initial Merlin engine had an ablative nozzle, much lower thrust, and no support for variable thrust.

          The first Falcon 1 flight was in 2006 and it was a failure. Not all of the issues were engine related but some, like those on the first flight, were engine related. The first successful flight only happened in 2008. That 2008 flight was done with Merlin-1C which was a regeneratively cooled, higher thrust, version of the engine.

          2008-2002 = 6 years.
          Sure they developed three basic versions of the Merlin (plus more for the upper stage variants) and one version of the Kestrel. But if this was a regular project the engine would have been developed with regenerative cooling to begin with. That adds more design complexity. So no even SpaceX couldn’t get the basic engine design right in less than 5 years.

          What they did do surprisingly fast was the Merlin-1D which supposedly was done in like 2-3 years time. The engine is basically all new. The pumps are different, the nozzle is different, it has variable thrust, etc. It goes to show you that once you have a highly experience team working in the same kind of problem for a couple of projects the time to do the project can be cut in roughly half.

          However an RD-180 replacement will have little in common. It will use LOX/Hydrocarbon staged combustion which is a wholly different ball of wax. It took like a decade or two to perfect these engines back in the 1960s-1970s. It is a non-trivial problem. Not all the knowledge from back then AFAIK is available on the US today. A lot of things will need to be relearned for sure. There are working copies of these engines and probably a lot of information on LOX/LH2 staged-combustion from the SSME plus some tests of things like the Integrated Powerhead Demonstrator. But that is about it.

          1. The Soviet Union started development of the NK-33 in 1968, tested it for the first time in 1970, and flew it for the first time in 1971. It was actually an offshoot of the NK-15, whose development spanned 1962-1964. During that period, Kuznetsov developed the oxygen-rich preburner staged combustion engine from scratch. You’re telling me that a third world country like the Soviet Union, working on a first-ever engine cycle, at a time when slide rules prevailed, could do it in 2 years, but its reasonable that we can’t count on being able to do it in 5?

            Here’s a pretty cool video on the subject.

            BTW, I know how complicated things are. I’ve been in this business for 35 years.

  6. Interestingly, Kent, Washington-based Blue Origin has told the Air Force it has no interest in taking government money for its BE-4 development effort, Hyten said. SpaceX…has expressed a similar sentiment, he said.

    High Five!

    Engineering design requirements by federal legislative committee sounds like a great idea. Only a kerosene engine could sufficiently protect my rights, and the studies to explore building it will only cost 260M$ + overruns + growth! Such a deal for this necessary pillar of freedom!

    2. The tooling is going to be a problem. The basic engine design (RD-170) was done in the 1970s in Russia. When the RD-180 was sold to the USA it came with the full technical specs and design documentation. However this AFAIK does not include manufacturing details like the coatings and treatments used to actually manufacture the engines. These would have to be reverse engineered.

      To the best of my knowledge the Russians did not do this in bad faith. They delivered the documentation the design bureau produced but the institutional knowledge in the machine shop which manufactured the engines was not included in that. Had US engine production actually started back then, as intended, I think they would have gladly given that knowledge as well. All it would take would be some trips to the machine shops. But with the current War on Ukraine I doubt they would be as forthcoming now. They also have been guarding their IP a lot more now.

      Rocketdyne-Aerojet should have somewhere the designs for the RD-180 and the SSME. They should also have information on the NK-33. In addition they have actual working hardware of all these engines they can reverse engineer.

      Blue Origin is working on a staged-combustion engine. Sure it is LOX/Methane but it doesn’t matter. The basic performance parameters will be similar and the engine should be a lot simpler to design. The only difference is the fuel tanks on the first stage will be bigger because Methane has lower density than Kerosene.

      1. When Aerojet originally went to Russia to look at their engines, they chose the NK engines because the Russians would not divulge the technology for coating the ducts of the ox-rich pre-burner for the RD engines. They still haven’t, but Mike Griffin seems to think we have figured it out, and I’ll take his word for it. Aerojet’s decision was based on the fact that the NK engines operate below a critical pressure where coatings become necessary. I think that’s the right approach, since the engines optimize out very nicely.

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