CAPE CANAVERAL, Fla. -- Lockheed Martin technicians inspect the second of NASA's twin Gravity Recovery and Interior Laboratory lunar spacecraft as they prepare to move it to a workstand in the Hazardous Processing Facility (HPF) at Astrotech Space Operation's payload processing facility in Titusville, Fla. In the HPF, the spacecraft will undergo two days of fueling activities.GRAIL will fly in tandem orbits around the moon for several months to measure its gravity field. GRAIL's primary science objectives are to determine the structure of the lunar interior, from crust to core, and to advance understanding of the thermal evolution of the moon. Launch aboard a United Launch Alliance Delta II rocket from Space Launch Complex 17B on Cape Canaveral Air Force Station is scheduled for Sept. 8.