Sean Lucara, Boeing Company B-1 structural analysis engineer, attaches A-20 doubling straps to the backbone of the B-1 during a structural modification at Ellsworth Air Force Base, S.D., Aug. 6, 2013. The modifications will nearly double the lifespan of the B-1 and increase combat capabilities. (U.S. Air Force photo by Airman 1st Class Alystria Maurer/Released)