Boeing NC - 135 The Boeing NC - 135 and NKC - 135 are special versions of the Boeing C - 135 Stratolifter and Boeing KC - 135 Stratotanker modified to operate on several different programs . Operational history . Readiness Program . In support of the U . S . Test Readiness Program that was initiated in response to the Limited Test Ban Treaty ( LTBT ) of 1963 , Sandia National Laboratories configured three NC - 135 aircraft as flying laboratories to support atmospheric testing of nuclear weapons , should testing have resumed . These aircraft were based at Kirtland Air Force Base . Work was initiated in 1963 and the aircraft remained in service with Sandia until 1976 , flying principally for Sandia , the Los Alamos National Laboratory and the Lawrence Livermore National Laboratory . The Atomic Energy Commission ( AEC ) maintained controlling oversight of the NC - 135 flight test aircraft . After 1976 , the aircraft flew for Air Force Weapons Laboratory . Airborne astronomy missions . While flying simulations for the Test Readiness Program , the science teams assigned to the NC - 135 aircraft realized that their flying laboratories could be effectively used to study solar eclipse s , cosmic ray s entering the atmosphere and the effects of magnetic fields in the ionosphere . Program scientists petitioned the AEC to allow for a program - within - a - program to use the aircraft for such scientific research . The petition was approved , and research continued through 1975 . The first eclipse mission took place from Pago Pago in 1965 , and flying in conjunction with several other science aircraft , one of the NC - 135s managed to fly within eclipse totality for 160 seconds , providing valuable science data . Eclipse missions were also flown in 1970 , 1972 , 1973 , 1979 and 1980 . Big Crow . " Big Crow " is the designation of the two NKC - 135 test - bed aircraft ( 55 - 3132 and 63 - 8050 ) heavily modified for electronic warfare testing , and to be used as a target simulator for flight testing the Boeing YAL - 1 Airborne Laser ( ABL ) . On March 15 , 2007 , the YAL - 1 successfully fired this laser in flight , hitting its target . The target was the NKC - 135E " Big Crow 1 " test aircraft that has been specially modified with a " signboard " target on its fuselage . The test validated the system ' s ability to track an airborne target and measure and compensate for atmospheric distortion . " Big Crow " aircraft are also used as downrange telemetry assets in conjunction with Western Launch and Test Range launches from Vandenberg Air Force Base in California . The Big Crow Program Office is coming to an end after over 30 years serving the US and its allies . The two " Big Crow " aircraft now rest in the storage at Davis - Monthan AFB , awaiting possible dismantling in 2009 . However , pending congressional legislation in 2009 may result in the aircraft being conveyed to a private civilian entity for continued R & D efforts . Other versions . One aircraft , serial 61 - 2666 , has been modified as an " NC - 135W " to test systems and equipment used on RC - 135V and W Rivet Joint reconnaissance aircraft . From 1975 to 1984 , the US used an " NKC - 135 " for its Airborne Laser Lab program . The modified NKC - 135A carried 10 . 6 micrometer green diode laser . Tests included successful interceptions of small air - to - air missiles such as the AIM - 9 Sidewinder and drone aircraft . Despite the combat potential of the system , it was kept strictly experimental . However , the SCUD threat faced during the Gulf War reignited interest in an airborne laser system , resulting in the Boeing YAL - 1 .