Lockheed D-21

The Lockheed D-21 is an American supersonic reconnaissance drone, designed to be launched from the back of an M-21, a variant of the A-12, and capable of more than Mach 3.3 at about 90,000 feet. Development began in October 1962 at Kelly Johnson's Skunk Works under the Lockheed designation Q-12, using A-12 technology: a double-delta wing, titanium construction and a modified Marquardt ramjet first built for the Bomarc missile. It was to carry one high-resolution camera over a preprogrammed path, release the camera module for recovery and then self-destruct. Captive flight tests on an M-21 began on 22 December 1964 and the D-21 was first launched from an M-21 on 5 March 1966. After a fatal accident on a launch from an M-21 the drone was modified to be launched from a Boeing B-52 with a booster rocket. Several successful test flights were made, followed by at least four unsuccessful operational flights over China before the program was canceled in 1971.