The 40/45 block upgrade is the largest modification on the U.S. AWACS fleet. It provides a complete replacement of mission computer systems - some of which were originally installed in the 1970s -- and a new open, network-based architecture, which enables future net-centric operations. While the improvements themselves are being completed by the 566th Aircraft Maintenance Squadron at Tinker Air Force Base, the program office at Hanscom has the role of lead integrator. (Air Force photo)