A worker installs one of the fins on the skirt of the Pegasus XL rocket that will launch the Space Technology 5 spacecraft.

Inside Orbital Sciences Building 1555 at Vandenberg Air Force Base in California, a worker installs one of the fins on the aft skirt of the Pegasus XL rocket that will launch the Space Technology 5 spacecraft later this month. ST5 contains three micro-satellites that will be positioned in a "string of pearls" constellation to perform simultaneous multi-point measurements of the Earth's magnetic field using highly sensitive magnetometers. The scheduled launch date is Feb. 28.