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      1. Delta 4 Rocket

        Delta 4 Rocket

        Description:


        The Delta IV family of launch vehicles is designed for optimum performance for a wide range of flight profiles, and is capable of carrying payloads ranging from 4,231 kg (9,327 lb) to 12,757 kg (28,124 lb) to geosynchronous transfer orbit (GTO). The Delta IV Medium, Medium-Plus and Heavy configurations are evolved, combining highly reliable, flight proven systems from Delta II and III, while incorporating the latest technology into a family of vehicles maximizing the use of common hardware.

        Commonality between all of the systems is central to the Delta IV. Each Medium & Medium-Plus vehicle uses a single common booster core (CBC), while the Heavy uses three CBCs. The Boeing Rocketdyne-built RS-68, a liquid hydrogen/liquid oxygen engine that produces 663,000 lbs of liftoff thrust, powers the first stage. This engine is mounted to the CBC first-stage structure and was designed for ease of manufacture by significantly reducing part count and thereby increasing reliability. Thirty percent more efficient than conventional liquid oxygen/kerosene engines, the RS-68 is environmentally friendly, producing steam as a combustion by-product. The three Delta IV Medium-Plus vehicles use a single CBC and are augmented by either two or four 1.5-meter (60-inch) diameter solid rocket strap-on graphite epoxy motors (GEMs).

        The cryogenic second stage is an evolutionary design incorporating the Redundant Inertial Flight Control Assembly (RIFCA) from Delta II and the Pratt & Whitney RL10B-2 engine. The Delta IV Medium & Medium-Plus (4,2) vehicles use the same 4-meter diameter second stage, while the Delta IV Medium-Plus (5,2), Medium-Plus (5,4) and Heavy vehicles use the same RL10B-2 engine, but have larger 5-meter diameter fuel tanks and stretched oxidizer tanks.

        On the Delta IV Medium & Medium-Plus (4,2), the payload is encapsulated in a 4-meter (13.1-feet) diameter payload fairing (PLF) for protection. On the Delta IV Medium-Plus (5,2), Medium-Plus (5,4) and Heavy, the payload is encapsulated with a similar 5-meter (16.7-feet) diameter payload fairing. Both the 4 and 5-meter diameter PLFs are composite bisector structures that were evolved from the Delta II 2.9 meter diameter and the Delta III 4-meter diameter PLFs. The Heavy vehicle can also employ a 5-meter diameter aluminum trisector fairing with Titan IV heritage.

        Boeing has successfully launched seven Delta IV launch vehicles. Delta IV's inaugural flight was marked by the successful launch of a commercial satellite on a Medium-Plus (4,2) in November 2002. Two Air Force communication satellites were successfully launched on Delta IV Medium vehicles in 2003, and the first Heavy vehicle was launched in December 2004.

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