M-21 Blackbird

M-21 #06940 in flight. Lockheed Photo

The M-21 is one of the few projects at the Skunk Works that was relatively unsuccessful. The M-21 is an A-12-like aircraft designed to launch the once ultra-secret D-21 Drone. When the United States signed a treaty to end flights of manned vehicles over the Soviet Union, an unmanned vehicle was needed for reconnaissance. Since the A-12 is an overflight vehicle, it would undermine the treaty if used in the future. Consequently, after A-12 #60-6939 was built, two aircraft called M-21s were built for the TAGBOARD program.

There were two M-21 aircraft built, 60-6940 and 60-6941. Aircraft #60-6941 crashed when the aircraft collided with a D-21 during the launch. This crash ended all M-21 sorties. Later on, the B-52H was used to launch the D-21 drone. The other M-21 is on Display at the Museum of Flight in Seattle, WA.