A B-1 bomber taxis down a runway prior to take-off during an Operational Readiness Exercise at Ellsworth Air Force Base, S.D., Feb. 23, 2012. In addition to B-1B missions, a variety of activities were conducted during the ORE to test the base’s ability to rapidly mobilize its aircraft, personnel and resources. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)