THE READY HEAVY

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 lb. in low-Earth orbit and nearly 30,000 lb. 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 lb.

As a vehicle already integrated and about to head to the pad, the Delta IV Heavy is a leading candidate to launch NASA's planned Orbital Space Plane (OSP) starting about 2008. The vehicle will supplement the shuttle on crew transfer missions to the International Space Station and expand human operations beyond Earth orbit. "We certainly believe the Delta IV Heavy has a bright future in the OSP program," said Dan Collins, Boeing's Delta IV project manager.