The Pegasus XL Expendable Launch Vehicle is on a workstand in the Multi-Purpose Processing Facility.

The Pegasus XL Expendable Launch Vehicle is on a workstand in the Multi-Purpose Processing Facility. The Pegasus XL will carry NASA's Solar Radiation and Climate Experiment (SORCE) into orbit. 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.