Three D-21 drones

The Lockheed D-21 was a Mach 3+ reconnaissance drone that began development in October 1962. Originally known by the Lockheed designation Q-12, it was intended to be launched off the back of the A-12 Oxcart for extra-long range flights and/or missions that were too dangerous for a manned vehicle. The A-12 variant developed to launch the D-21 drone was designated the M-21. The D-21, with a single Hycon high-resolution photographic camera, was designed to fly over a pre-programmed location, and then drop the hatch containing the camera into the ocean, where it could be retrieved.