Pratt and Whitney Rocketdyne announced Monday it has been selected by NASA to provide a new version of its Apollo-era J-2 as the propulsion system for the agency's Crew Launch Vehicle upper stage in the next decade.

Up-rated in power and designated the J-2X, the hydrogen/oxygen-fueled engine will be rated for human flight, the company said in a news release. The first launch of a human aboard the J-2X-powered CLV is planned for 2012.

NASA's baseline effort calls for seven development engines, two certification engines and one flight-only engine. The initial contract value is $50 million.

NASA based its decision on the J-2's performance history as part of the Apollo program, and the fact that the agency could utilize an engine in this thrust class for both the CLV upper stage job and, in the future, to power the Earth Departure Stage for lunar missions that will be lofted on the planned Cargo Launch Vehicle, P&WR's release said.

J-2 derivative turbomachinery was used for the powerpack in the XRS-2200 aerospike development engine for NASA's X-33 hypersonic vehicle, which was hot-fire tested in 2000. That test demonstrated PWR's ability to build and integrate the hardware, the company said.

In awarding the contract, NASA also cited PWR's long experience in the development of major booster engines as credentials for producing the new J-2X.