In the Multi-Purpose Processing Facility, a technician cleans NASA's Solar Radiation and Climate Experiment (SORCE) before its mating to the Pegasus XL Expendable Launch Vehicle. Built by Orbital Sciences Space Systems Group, SORCE will study and measure solar irradiance as a source of energy in the Earth's atmosphere. The launch of SORCE is scheduled for Jan. 25 at 3:14 p.m. from Cape Canaveral Air Force Station, Fla.