The first U.S. Air Force/Boeing "Delta IV Heavy" Evolved Expendable Launch Vehicle, a strong candidate to be the next U.S. manned launch vehicle, has been assembled here in preparation for rollout to Launch Pad 37B for several months of checkout before a demonstration flight in May 2004. The nearly 2-million-lb.-thrust vehicle combines three Delta IV common booster cores and three Rocketdyne liquid oxygen/hydrogen RS-68 engines. The IV Heavy, and its enlarged upper stage, powered by an advanced version of the Pratt & Whitney RL10 oxygen/hydrogen engine, is designed to place more than 50,000 1b. in low-Earth orbit and nearly 30,000 1b. into geosynchronous-transfer orbit. Once fully stacked and loaded with propellant, the vehicle will stand 235 ft. tall and weigh more than 1.6 million 1b.
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