XCOR Aerospace and United Launch Alliance (ULA) said they made more headway on plans to produce piston-driven rocket engines, testing a liquid-hydrogen pump that they believe could drastically reduce the cost of space launches. 

In the test, which took place at an XCOR facility in Mojave, Calif., the company “successfully operated our liquid hydrogen pump at full design flow rate and pressure conditions,” XCOR Chief Executive Jeff Greason said in a Sept. 23 press release.

XCOR has now racked up about 21 hours of testing on the pump, Andrew Nelson, XCOR’s chief operating officer, said in a Sept. 25 email. XCOR has also been helping ULA test piston-driven liquid-oxygen and liquid-kerosene pumps. 

Those tests have been going on over the past nine years, Nelson said, at a cost of about $10 million to XCOR. 

“ULA is interested in potentially implementing piston pump fed engines on Centaur, Delta Cryogenic Second Stage, and ULA’s future advanced common evolved stage,” Nelson wrote in his email. The Centaur is the cryogenic upper stage on ULA’s Atlas 5 rocket.

XCOR eventually plans to test out the piston-pump technology in some of the rocket-powered vehicles it is developing, Nelson said. The company’s two-seat suborbital spaceplane, Lynx, is set to begin flight testing later this year, with an eye toward starting commercial flights in 2015. 

Pump-fed rocket engines are usually driven by turbines manufactured by a small pool of specialized suppliers. Transitioning to pistons would allow rocket engine makers to tap into a much larger automotive supply chain, where engineers have already performed decades of mechanical debugging. That could reduce the price of rocket engines to “a fraction of today’s costs,” Nelson said.