Technicians on Cape Canaveral Air Force Station, Fla., work to attach the Pegasus XL launch vehicle and Solar Radiation and Climate Experiment (SORCE) to the L-1011 aircraft. The L-1011 will carry the Pegasus to the launch altitude of 39,000 feet over the Atlantic Ocean approximately 100 miles east-southeast of Cape Canaveral. SORCE, built by Orbital Sciences Corporation, 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 CCAFS.