ATK and United Launch Alliance conducted a successful cold-temperature ground test Sept. 6 of a Graphite Epoxy Motor (GEM-60) solid rocket motor used to boost ULA’s Delta IV launch vehicles.
The 60-inch diameter and 53-feet long motor, which was chilled to a core temperature of 30 degrees F, performed as designed, producing approximately 270,000 pounds of thrust and burned for 90 seconds. The test was the second in a series to qualify new fixed and vectorable nozzles manufactured by ATK for flight readiness.
“This test further qualifies ATK’s in-house capabilities in manufacturing commercial nozzles as flight ready,” said Scott Lehr, vice president and general manager, ATK Aerospace Group, Defense & Commercial Division. “Utilizing ATK nozzles not only provides better value to our customer, it also helps further secure employment of our skilled workforce.”
During the GEM-60 static motor firing, the rocket motor performed at cold temperatures within specifications. The successful test qualifies the new fixed nozzle for flight motors and validates the performance of new nozzle insulation at the lowest range of operational temperatures.
“GEM-60 motors have successfully boosted ULA’s Delta IV Medium+ launch vehicles 11 times since 2002,” said Mark Wilkins, ULA’s vice president of Program Operations. “These ground tests are an important part of qualifying modifications and upgrades to flight hardware, as well as ensuring mission success on future flights.”
The GEM-60 motor is a strap-on booster that was developed for ULA by ATK in 2000 to increase the payload-to-orbit capability of the Delta IV Medium+ launch vehicle. The first two-motor configuration boosted the inaugural flight of the Delta IV launch vehicle family in November 2002, and the first four-motor configuration flew in 2009.