The Airborne Laser Lab was a gas-dynamic laser mounted in a modified version of a KC-135 used for flight testing. Similar to the commercial Boeing 707, the slightly smaller KC-135 was designed to military specifications and operated at hight gross weights. The NKC-135A (S/N 55-3123) is one of 14 KC-135As permanently converted for special testing. It was extensively modified by the Air Force weapons Labratory at Kirtland AFB, New Mexico, and used in an 11-year experiment to prove a high-energy laser could be operated in an aircraft and employed against airborne targets. During the experiment, the Airborne Laser Lab destroyed five AIM-9 Sidewinder air-to-air missiles and a Navy BQM-34A target drone.
