Ares Power.

The article reports on the changes made by the U.S. National Aeronautics and Space Administration (NASA) to the propulsion system design of its Ares I crew launch vehicle, as the agency copes with cost, weight and performance concerns. Cost and weight issues with composites have forced the agency back to a metal nozzle for the Pratt & Whitney Rocketdyne (PWR) J-2X rocket engine that will power the Ares I crew launch vehicle. Steve Creech, Ares V integration manager, says NASA's goal is a nine-ton margin.