Awesome Video of XCOR’s Landmark Engine Run

Video Caption: 67 second engine test featuring XCOR’s 2,500 lb-thrust Lynx main engine (one out of four engines). This engine is fed entirely by XCOR’s revolutionary rocket propellant piston pumps, which are far more cost effective and manufacturable than turbopumps. Both the liquid oxygen oxydizer and kerosene fuel are being pumped into the engine using this techonology. For more information, see our press release at

  • Andy

    How well does a piston pump scale? Can you feed a 150,000 lbf engine with a piston pump?

  • Aerospike

    Don’t know about 150,000 lbf, but ULA (not sure if it was LM, Boeing, or both) have been talking about improvements for their upper stages (Centaur or DCSS) possibly using XCORs piston pumps (both have collaborated with XCOR as far as I know) and in this case we are talking about engines in the class of 25,000 lbf (RL10).

  • XCOR has been working with ULA on a replacement for the RL-10 engine on the Centaur. There is also an internal ULA program to upgrade the Centaur stage as a vehicle. If it all works out, the Centaur fitted with a reusable XCOR engine could serve multiple roles, including a fuel depot and space tug. It would be a key element in a cis-lunar transportation system.

  • jb

    @doug if spacex’s falcon 9 forces the cost of launches down the pump looks like a bit of a game changer for many applications as you mentioned. going to be fun next few years to watch. Hope more investors/companies get involved and a new industry kicks off

  • XCOR’s engine technology and operating philosophy are very interesting. The point is to prove they can do suborbital transport multiple times per day on an affordable basis using the same vehicle. They then want to use that expertise and the technology they’re developing to do a fully reusable two-stage-to-orbit air-launch system.

    XCOR’s goal is just as ambitious as the one Musk is pursuing in terms of reusability, but it’s a different approach. And that’s good because you want people going down different technological paths.

  • Inda

    What advantages do the propellant piston pumps have over traditional centrifugal compressors? In hindsight, this seems like a reinvention of the wheel.

  • Andy

    To my knowledge there is no centrifugal *compressor* in a turbopump. You usually have one or more turbine stages driving in or more centrifugal *pump* stages. Turbopumps are difficult for a lot of reasons. One reason is the awkward thermal environment created by having hot turbine gas in close proximity to a cryogenic propellant. The bearings and seals are difficult to develop – seals contribute stiffness and damping to your system in ways that aren’t always easy to predict. Also, you have turbomachinery operating at high speeds and tight tolerances that have to survive the dynamic loads of launch.

  • Andy

    So we’re talking upper stages or engines operating in vacuum? Is it suitable for a first stage engine? An RL-10 is certainly bigger than 2,900 lbf but it’s not the 1XX,000 lbf of a Merlin 1D. Don’t get me wrong – I think the piston pump fed engine is an outstanding innovation & I’m rooting for XCOR…I’m just trying to wrap my brain around where the piston pump fed engine fits in the big scheme of things.

  • Andy

    There’s a low quality picture at this link (Doug, are we allowed to post links?) that illustrates the extreme thermal environment well.

    The turbine housing is glowing red hot but the pump is covered in frost. There aren’t any dimensions on the picture, but I can’t imagine the two parts are much more than 2 feet from each other.