[SatNews] XCOR Aerospace has completed the latest test series for the liquid hydrogen engine it is developing for United Launch Alliance (ULA).

This is an important milestone in the long-running LH2 (liquid oxygen and liquid hydrogen) program and is also a step toward running the engine in a fully closed cycle mode. In its most recent milestone, XCOR successfully performed hot fire testing of the XR-5H25 engine's regeneratively cooled thrust chamber, with liquid oxygen and liquid hydrogen propellants supplied in pump-fed mode, using XCOR's proprietary piston pump technology.

Upcoming test series will fully integrate the nozzle with the engine and piston pumps. Fully closed cycle testing will follow soon afterwards and will complete the sub-scale demonstration engine program. The XR-5H25 engines are being developed under contract to ULA as potential successors to the Delta and Atlas series upper stage engines currently used. These engines will also help power orbital launches.

"This test marks the first time liquid hydrogen and liquid oxygen have been supplied to a rocket engine with a piston pump," said XCOR Chief Executive Officer Jeff Greason. "It is also the first time an American LH2 engine of this size has successfully fired liquid hydrogen and liquid oxygen together in pump-fed mode. This will also bring us to a new phase in our plans for orbital flight.

The XCOR Aerospace infosite is located at http://www.xcor.com/

The United Launch Alliance infosite is located at http://www.ulalaunch.com/