The Lockheed D-21 was an American Mach 3+ reconnaissance drone. The D-21 was initially designed to be launched off the back of its M-21 carrier aircraft a variant of the Lockheed A-12 aircraft. Development began in October 1962. Originally known by the Lockheed designation Q-12 the drone was intended for reconnaissance missions deep into enemy airspace.
Made by Lockheed Corporation.
It is the successor of the Lockheed A-12 .