Engineers from Johns Hopkins University test for true perpendicular solar array deployment of the Advanced Composition Explorer.

Applied Physics Laboratory engineers and technicians from Johns Hopkins University test for true perpendicular solar array deployment of the Advanced Composition Explorer (ACE) in KSC’s Spacecraft Assembly and Encapsulation Facility-II (SAEF-II). The white magnetometer boom seen across the solar array panel will deploy the panel once in space. Scheduled for launch on a Delta II rocket from Cape Canaveral Air Station on Aug. 25, ACE will study low-energy particles of solar origin and high-energy galactic particles. The ACE observatory will be placed into an orbit almost a million miles (1.5 million kilometers) away from the Earth, about 1/100 the distance from the Earth to the Sun