A successful cold-temperature ground test of a Graphite Epoxy Motor (GEM-60) solid rocket motor used to boost ULA Delta IV launch vehicles was successfully conducted Thursday by ATK and United Launch Alliance (ULA). The main test objectives from the static motor firing were measuring the rocket motor's performance at cold temperatures, qualifying a new vectorable nozzle on the motor and verifying the performance of new nozzle insulation at the lowest range of operational temperatures. Additionally, the test provides qualification for transitioning nozzle manufacturing operations from an outside supplier to ATK.
"This motor firing is an important test for ATK, as we have expanded the use of our in-house capabilities." said Scott Lehr, vice president and general manager, ATK Aerospace Group, Defense & Commercial Division. "By manufacturing the nozzles ourselves, we are able to provide a better value for our customers."
The successful test of the 60-inch motor is considered an important milestone in the GEM-60 vectorable nozzle qualification. Initial test data indicate that the 60-inch diameter and 53-feet long motor, which was chilled to a 30F core temperature, performed as designed, producing approximately 270,000 pounds of thrust and burned for 90 seconds. "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. "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 vehicles. The first two-motor configuration of the GEM-60 boosted the inaugural flight of the Delta IV launch vehicle family in November 2002, and the first four-motor configuration flew in 2009. The next GEM-60 motor test is scheduled for September and will be a fixed nozzle test.