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Inside the Tech of SpaceX's Homegrown Rocket Engine 82

Posted by timothy
from the see-fig-1 dept.
An anonymous reader writes with this excerpt from a look at the engine behind SpaceX's Falcon rocket, the Merlin: "The rockstar of SpaceX may be Elon Musk, but the lead man behind the fire power is Tom Mueller. He is the Vice President of Propulsion Development and founding employee at SpaceX. Musk sought Mueller out in 2001 when Musk decided to build his own rockets instead of buying some from the Russians. Musk caught wind of a rocket engine Mueller built in his garage and 'apparently had a religious experience' once he saw it. If you didn't know, Elon Musk used $100 million of his Paypal money to start SpaceX. That money was used to build the Merlin engine Mueller had designed. The Merlin engine is the first new American booster engine in ten years and only the second in the last 25 years."
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Inside the Tech of SpaceX's Homegrown Rocket Engine

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  • by Lifyre (960576) on Tuesday January 15, 2013 @09:35AM (#42590875)

    One of these days...

  • by Anonymous Coward on Tuesday January 15, 2013 @09:40AM (#42590911)

    And not with a paid team working on a pay check.

    • by Bo'Bob'O (95398) on Tuesday January 15, 2013 @02:51PM (#42595569)

      Bullshit

      Just off the top of my head: Teflon (dupont), the transistor (Bell Labs), the GUI (Xerox Parc), the blue LED (Nichia). The list goes on and on of things that have been major game changers that came from a group of smart people getting a paycheck putting their heads together or building on each other's work on something new.

      That's not to say that there aren't impediments to innovation today, be it short sighted investors or patent issues, but a great deal of big innovations, if not many of the biggest in the last 100 years have come from academics on grants and guys on salaries. What seems to be special about SpaceX is that those are the guys that seem to be the focus in the company rather then much larger (less flat) companies that are mostly about managing management and pleasing investors.

      • by PiMuNu (865592)
        A couple more
        • The LASER
        • Superconductor (concept)
        • Superconducting wires
        • Particle accelerators

        The list is endless

  • by vlm (69642) on Tuesday January 15, 2013 @09:59AM (#42591087)

    No religious experience here (then again, never seen in person) but everything I've read is the Merlin series is all about Chapman's "simplify and add lightness" which a lot of the old time aerospace pioneers used to use before they became profit munching incumbent contractors.

    Pintle injector for throttling, stability, and some wall cooling. Damn good idea.

    Don't wanna run a completely isolated hydraulic system and include a zillion new single points of failure? Hmm how bout using the fuel as the hyd fluid. How bout pressurize the hydraulic "fluid" using the main turbopump. Damn good idea.

    The vacuum model uses radiative cooling. I'm sure a fat cat modern contractor would try for regenerative just to boost the contract cost / profit, but they're the "simplify and add lightness" people so simple radiative. Hardly a new idea for vacuum nozzle cooling, but a damn good one anyway.

    They also show great judgment in knowing their own limitations, they buy their turbopumps from a specialist. Things that need to be custom they do, things that can be COTS are COTS.

    I hope they can stay on task with the whole "simplify and add lightness" thing. The X and XX sound a little more like something you'd see from the incumbents rather than startups. Unless they have secrets up their sleeves, which is certainly possible.

    Maybe the standard /. car example is the Merlin is as minimal as can possibly be made that'll work, like a 60s muscle car engine or a race car engine, whereas the incumbents are more like a modern engine which is mostly an elaborate emissions control system, oh and with an engine bolted onto it almost as an afterthought.

    • by Anonymous Coward

      I think the incumbents are driven, to a certain extent, by NASA's desire to have the best possible, something that I'm sure the engineers and management at the contractors encourage. If you were a rocket engineer, would you want to work on just another engine from the 50s &60s, or something that pushes the state of the art of rocketry? (NASA has a legal and institutional mandate to do the latter, only)

      the Shuttle Main Engine was described as probably the most sophisticated, highest performance rocket

      • by camperdave (969942) on Tuesday January 15, 2013 @12:22PM (#42593321) Journal
        The Space Shuttle Main Engine designs (Block 0) for the test benches had a certain rated thrust. That benchmark became 100%. When the production designed engines (Block 1) came online, the improvements meant that they were capable of greater thrust than that initial benchmark. Rather than call the new value 100%, they based it on the Block 0 design benchmark. The later engines (Block 2) were capable of 111%.

        The engineers working on the shuttle engines were not necessarily trying to improve thrust; not trying to eke out an extra percent or two like a dragster or racecar mechanic would. They were just doing stuff like replacing a turbo pump with a different turbo pump that had half the moving parts, or changing the casting process so there were fewer welds; things that would make the engines lighter, more robust, and easier to manufacture.
    • I read somewhere that they're talking turbopump production in-house.

    • by Woek (161635)

      I always prefer removing heaviness instead of adding lightness...

    • by DerekLyons (302214) <fairwater@gmFREEBSDail.com minus bsd> on Tuesday January 15, 2013 @11:34AM (#42592447) Homepage

      Don't wanna run a completely isolated hydraulic system and include a zillion new single points of failure? Hmm how bout using the fuel as the hyd fluid. How bout pressurize the hydraulic "fluid" using the main turbopump.

      Not so much. You've eliminated the turbopump (trading that for a modest increase in fuel system complexity), but pretty much all the rest of the hydraulic system failure modes are still there.
       

      The vacuum model uses radiative cooling. I'm sure a fat cat modern contractor would try for regenerative just to boost the contract cost / profit

      A 'modern' contractor would probably use regenerative because it's a very efficient means of cooling, and modestly boosts engine performance by preheating the fluid (fuel or oxidizer) used for combustion.
       
      One educated in the history of rocketry will know that regenerative cooling far predates the 'modern' contractor - and was chosen even when expensive and difficult. Someone intelligent would ponder on why that might be. Confronted with reality, the dogmatic simply ignores this and repeats his magic catchphrase like a cargo cultist.
       

      I hope they can stay on task with the whole "simplify and add lightness" thing. The X and XX sound a little more like something you'd see from the incumbents rather than startups

      No, they sound more like something you'd see from someone who wants/needs a certain level of performance and has the budget to go after it rather than fitting together a solution on the cheap. The dogmatic may prefer they stick with his mantra, but SpaceX seems to be made of pragmatists rather than dogmatics.
       

      Maybe the standard /. car example is the Merlin is as minimal as can possibly be made that'll work, like a 60s muscle car engine or a race car engine

      Spot on. Which means it's horribly inefficient compared to more modern designs, along with being heavier, with less efficient lubrication and cooling, and lower performing. It's the engine of the classic car enthusiast and the biased who believe that everything was better in some imaginary golden age. To everyone else, it's a quaint anachronism.

      • by MojoRilla (591502)
        I'm not an expert on rockets, and don't know if your comment is true or hyperbole. But it seems that the more modern designs costs 2x or more what SpaceX does to get to LEO. [wikipedia.org] How can such a horribly inefficient design cost so much less to fly?
      • by Karrde45 (772180) on Tuesday January 15, 2013 @05:32PM (#42597325)
        The Vacuum optimized Merlin 1C is both regenerative and radiatively cooled. The main copper chamber is regen, and the columbium extension is radiative.

        In general, the Merlin as a booster engine is far lighter and much cheaper than hydrolox booster engines (but much more inneficient). They are slightly lighter and much cheaper than typical russian kerolox booster engines (and slightly less efficient than them).

        I wouldn't say the Merlin is horribly inefficient, more that it's focused on optimizing cost and thrust to weight ratio rather than ISP. There really hasn't been much in the way of American development of kerolox engines lately. Most people focus on hydrolox development or buy Russian kerolox.
        • There really hasn't been much in the way of American development of kerolox engines lately.

          Quite the contrary - there's been considerable work related to a revived F-1, and both NASA and the USAF have been looking at new hydrocarbon engines in order to get away from the Russian RD-180.

  • by StoneyMahoney (1488261) on Tuesday January 15, 2013 @10:09AM (#42591143)

    "Merlin" is an engine brand of Rolls-Royce, a V12 piston engine from the 30's onwards used in a wide variety of aircraft. I can imagine raised eyebrows in their offices, but would they actually sue? I hope not, that would show these lawsuit-happy Yanks what British class really is.

    • "Merlin" is an engine brand of Rolls-Royce, a V12 piston engine from the 30's onwards used in a wide variety of aircraft. I can imagine raised eyebrows in their offices, but would they actually sue? I hope not, that would show these lawsuit-happy Yanks what British class really is.

      It's a different market segment, so the trademark can't be enforced in that way in the USA.

    • The Rolls Royce Merlin is famous indeed. It was the engine that won the Battle of Britain.

      http://www.bombercommandmuseum.ca/s,93_2merlin.html [bombercommandmuseum.ca]

  • by peter303 (12292) on Tuesday January 15, 2013 @11:23AM (#42592267)
    SpaceX is supposed have about 10-20% ex-NASA people, mainly younger folk. Dont think of NASA as automatically bloated - it was the only game for aspiring rocket scientists before the 2000s. Recycling NASA people preserves some of their experience. One of the problems with the Orion program is that a lot of the good Apollo ideas had been lost due to retirement of those engineers and loss of record.
  • by theNAM666 (179776) on Tuesday January 15, 2013 @11:33AM (#42592431)

    Goddard wanted to build spinning engines which used the rotary pressure to increase thrust-to-fuel ratio; visible in his posthumous patents.

    Some basic info at (follow the links):

    http://www.halfwaytoanywhere.com/ [halfwaytoanywhere.com]

  • No Garage here (Score:5, Informative)

    by phypsilon (140518) on Tuesday January 15, 2013 @11:38AM (#42592505)

    I suggest you to look up TRW and the Low Cost Pintle Engine (LCPE) on the internet. Guess who was head of liquid rocket propulsion development there back at the start of the century.....

  • I didn't know about this... I guess the Falcon Heavy is still not enough for a manned Mars mission so they're gonna build the Big Fucking Rocket.

    Glad I actually RTFA

  • They're not breaking any records or anything but not bad. The MerlinC engine is around 300 Isp (specific impulse, the engine efficiency for those who don't know). That's not blowing away the Space shuttles specs (~400 Isp) but it also doesn't cost $40 Million per engine or use Liquid Hydrogen.

Forty two.

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