In the Multi-Purpose Processing Facility, the Pegasus XL launch vehicle is ready for installation of the Solar Radiation and Climate Experiment (SORCE) satellite after encapsulation. Built by Orbital Sciences Corporation (OSC), 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. The drop of the Pegasus will be from OSC's L-1011 aircraft at an altitude of 39,000 feet over the Atlantic Ocean approximately 100 miles east-southeast of Cape Canaveral.