The ULA Delta II rocket blasts off at Vandenberg AFB, California. (Picture by Carleton Bailie, ULA.)
The ULA Delta II rocket blasts off at Vandenberg AFB, California. (Picture by Carleton Bailie, ULA.)

The rocket carried the United States Missile Defense Agency (MDA)'s Space Tracking and Surveillance System Advanced Technology Risk Reduction (STSS-ATRR) satellite into orbit.

The STSS ATRR is a small experimental satellite that serves as a pathfinder for next-generation sensor technology for future MDA space missions. MDA is pursuing a space-based sensor layer to detect missile launches, provide continuous target tracking, and pass track data to missile defence interceptors.

ATK designed, fabricated and tested the Optical Bench for the satellite. The bench is a critical composite structural assembly providing the required stability for the payload sensors onboard the spacecraft. ATK also provided engineering analysis for the precise thermal and moisture distortion performance of the payload bench required to meet mission expectations in the harsh environment of space.

Nine ATK GEM-40 solid propulsion strap-on boosters provided augmented thrust for the launch. Six of the boosters ignited at lift-off with the first-stage main engine and provided over 824,000 lb maximum thrust. Just over one minute later, the remaining three boosters ignited to provide an additional 427,000 lb maximum thrust. The spent motors were then jettisoned from the rocket as it continued its ascent.

ATK manufactured the GEM-40 motors at its facility in Magna, Utah. The composite cases for the GEM-40 boosters were produced at ATK's Clearfield, Utah, facility and are made of graphite epoxy material using an automated filament winding process. The 10 ft diameter composite payload fairing, encapsulating the third stage that holds the payload, was fabricated by ATK's Iuka, Mississippi facility. The fairing was produced using hand lay-up manufacturing. This launch marks the 16th ATK-built fairing flown on a Delta II mission.