Artistic rendition of the U.S.A.F.’s WGS-5 satellite.
This was the third time the Delta IV medium-plus rocket featured four ATK 60-inch diameter Graphite Epoxy Motors (GEM-60). The 53-foot-long motors were mounted in pairs on opposing sides of the rocket, with one fixed and one vectorable nozzle per side. They burned for 90 seconds and provided more than 1.1 million pounds of thrust to assist delivery of the WGS-5 satellite to its determined orbit. The composite cases, nose cones and aeroskirts for the GEM motors were fabricated at ATK’s Clearfield, Utah, facility. The solid rocket motors were produced at ATK’s Magna, Utah, facility. ATK has manufactured 58 GEM-60 boosters for the Delta IV launch vehicle since the initial flight in 2002.
The nozzle for Delta IV’s RS-68 engine was designed and manufactured at ATK’s Promontory, Utah, facility. The Pratt & Whitney Rocketdyne-built RS-68 is the largest hydrogen-fueled engine in the world. ATK also designed and produced the nozzle’s thermal protection material, which is capable of shielding the nozzle from the extreme heat of launch when external temperatures can exceed 4,000 degrees Fahrenheit.
For the Delta IV medium-plus launch vehicle itself, ATK supplied nine key composite structures, including the Interstage that provides the interface between the Common Booster Core and the cryogenic second stage, a Centerbody that integrates the liquid oxygen (LO2) and liquid hydrogen (LH2) tanks, a Thermal Shield that protect the RS-68 engine during ignition and flight, and an LO2 Skirt. Additionally, the payload is encapsulated by a five-meter-diameter composite payload Fairing, along with required hardware for payload integration: Nose Cap, X-Panels, Payload Attach Fitting, and Payload Attach Fitting Diaphragm. The structures are five meters in diameter and range from one to 15 meters in length. They are all produced using advanced hand layup, machining and inspection techniques at ATK’s manufacturing facility in Iuka, Miss., with the exception of the X-Panels, which are produced at ATK’s facility in Clearfield, Utah.
ATK also provided the propellant tank for the Delta IV upper stage roll control system. The tank was manufactured at ATK’s Commerce, California, facility.
WGS supports the defense communications system, the U.S. Army’s ground mobile forces, the U.S. Air Force’s airborne terminals, the U.S. Navy’s ships at sea, the White House Communications Agency, the U.S. State Department and other special users.
