Xcor has announced the completion of full-flow tests for its hydrogen piston pump, a primary component of a next generation upper stage engine.
The piston pump is designed to replace the system that keeps the liquid hydrogen fuel and liquid oxygen oxidizer tanks pressurised. The pump is being designed with United Launch Alliance (ULA), which procures and launches most US government payloads.
“This milestone builds on our earlier success with liquid oxygen and kerosene pumps, which have powered many of our hotfires,” says Jeff Greason, Xcor’s chief executive. “Achieving this goal allows us to proceed with integrated testing of our liquid hydrogen demonstrator engine, fed by our liquid hydrogen and liquid oxygen piston pumps. The ultimate goal is a far more cost-effective upper-stage engine for ULA and their customers.”
The pump is destined for a new second stage engine, to be used in the Delta IV’s Delta Cryogenic Second Stage and Atlas V’s Centaur Upper Stage. Currently the second stages of both rockets, known collectively as Evolved Expendable Launch Vehicles, are powered by the Aerojet Rocketdyne RL-10. The RL-10, while highly dependable, is also extremely complex – and as a result, very expensive.
The RL-10 uses pressurised helium to force the hydrogen and liquid oxygen from their separate tanks into the combustion chamber, where they are combined and set alight. Xcor’s new piston pump will be used to transfer the fuels directly, which would greatly decrease engine complexity and weight.