Video of Virgin Orbit NewtonFour Hot Fire

Video Caption: LauncherOne is powered by two rocket engines—a single NewtonThree on the main stage and a single NewtonFour on the upper stage. Both engines are turbopump-fed, gas generator cycle, LOX/RP-1 engines developed in-house here at Virgin Orbit. Here’s a typical test of the NewtonFour on our test stand up in Mojave, CA, in which the engine runs for a full six minutes—the same duration it would run during a full orbital launch. By popular demand, we’re posting this in real time–all six minutes of rockety goodness!

  • Jimmy S. Overly

    Looks like LauncherOne and its Newtons are headed in the right direction. Nice work.

  • JamesG

    I’m curious of the engineering/business logic that led them to develop two separate engines instead of sizing one for the upper stage and then just ganging up a bunch of them for the 1st stage.

  • duheagle

    I share your curiosity.

    And why turbopumps? This is an expendable launch vehicle architecture. Tossing a couple expensive turbo powerheads into the drink on each mission does nothing good for mission economics. Mass-produced pressure-fed engines in a large cluster on the first stage and a small cluster on the second would seem far more reasonable for a throw-away.

    And for those still worshipping at the altar of minimized part count, clustered pressure-feds with shared tankage and valving should, by rights come in way below any kind of turbo-pumped engine.

    Not to mention the ease with which larger LauncherTwo’s and LauncherThree’s could be implemented based on market demand. Or even a Vector-class LauncherZero.

    Tis a puzzlement.

  • redneck

    I may be in serious disagreement with you here. Some turbopump architectures are not necessarily that expensive. That may or may not be true in this case. Just because it is possible to do something inexpensively does not imply that this group did.

  • savuporo

    Okay, you have to go to youtube and turn on closed captions for this video. Brick Tamland endorsed

  • patb2009

    parts count?

  • redneck

    Legacy space concepts. Optimization suggests one engine perfected for each stage, neglecting development and production costs of course.

  • duheagle

    You could be right. But I don’t think Virgin Group has earned much benefit of the doubt where their engineering is concerned.

  • JamesG

    Is double with two separate engines. Unless they only ever expect to make a handful of these vehicles and engines. Economies of scale and all that…

  • Jimmy S. Overly

    I suspect you’re alluding to Merlin. I’ve heard from people at SpaceX that MVac and M1D share a name, cycle, and propellant combo – but they’re very different engines. MVac isn’t just and M1D with a bigger nozzle.

  • patb2009

    You’ve got two different discussions here… Your proposal is EngineX where you put 10X on the bottom and 1X on the second stage. It’s possible but you get 11X Valves, drains, regulators, sensors, etc….

    The other choice is Design Engine X and Engine Y where Y is 10X…

    Now you have 2X the number of unique parts ( Pipes, regulators, sensors) and 2X Design processes and 2X test processes. However,
    you have fewer total parts, connections, etc…..

    Most entities prefer reducing the total number of parts.

    Certainly SpaceX opted for 9 Merlins and one Merlin US for the Falcon 9.

  • JamesG

    Serially produced parts are cheap. Especially if you are buying them in gross. What is expensive is developing the parts in the first place, and tuning them to produce a reliable, efficient engine. And it is as expensive each time you develop an engine of a certain size/power, even if similar.

  • JamesG

    Yeah but it does share all the prior R&D art.

    Actually I was thinking of both the SpaceX and RocketLabs. Of all the New Space companies, the two that have succeeded (or come the closest to success) have used the same approach. That is probably not a fluke.

  • duheagle

    I think the sea-level M1-D and the M1-D Vac are likely to be more similar now than before. The Vac always had an in-flight restart capability, for example. Up until the FT debuted, I don’t think the sea-level M1-D did. It’s certainly far from obvious to me why these two engines would have to differ in much more than their nozzle geometry. But I’m certainly willing to entertain an explanation if anyone cares to provide such.

  • duheagle

    For a given class of engine, your argument has at least rough arithmetic validity. But for a cluster of pressure-fed engines operating off common tankage and valving vs. a complex turbo-pumped engine, the comparison might well go in the other direction.

    Even anent the same class of engine, simply reducing parts count is not always a road to maximum reliability. One big disk storage drive has fewer moving parts than a cabinet full of smaller ones but the cabinet full of smaller drives can be arranged so that the failure of any single storage drive doesn’t take the whole cabinet down. The term of art in computing is RAID array. In rocketry it’s engine clustering.

  • Jimmy S. Overly

    Oh yeah, I totally forgot Rutherford/RocketLabs. Good point.

  • HyperJ

    How many all pressure-fed launch vehicles exist? I can’t think of any.
    (I could be very wrong, please correct me if I am)

    Pressure fed is one of those things that sound great, but the performance never seems to quite get there.

  • patb2009

    If all your failures are benign sure…

    If you have cascadable failure modes, that’s just increasing bad.

  • patb2009

    https://www.youtube.com/watch?v=dvTIh96otDw&ab_channel=SpaceKSCBlog

    Here is a great example of both arguments.
    1) The Falcon 9 pushed through the failure. The Valves closed, the GNC adjusted and the bird burned a few seconds longer.

    2) The Merlin threw high velocity shrapnel all over. It could easily have caused cascading failure.