 J-2X

The J-2X is a liquid-fueled cryogenic rocket engine that was planned for use on the Ares rockets of NASA's Constellation program, and later the Space Launch System.Built in the United States by Aerojet Rocketdyne (formerly, Pratt & Whitney Rocketdyne), the J-2X burns cryogenic liquid hydrogen and liquid oxygen propellants, with each engine producing of thrust in vacuum at a specific impulse ("I"sp) of .