Lockheed Q-12/D-21 Tagboard drone
The D-21 came out of the CIA sponsored A-12 program. For photo targets which were too sensitive or too far away for manned A-12 flights, the unmanned D-21 was developed. The D-21 was powered by a Marquardt RJ43-MA-11 ramjet, similar to the engine used on the Bomarc missile.
The original plan was to launch the D-21 from a M-21 mothership (a modified A-12), but the 4th test flight destroyed the drone and the mothership; and operationally the D-21B was dropped from a B-52H with a solid propellant booster to get the craft up to a speed where the ramjet could operate.
Lockheed Q-12/D-21 Tagboard drone
The D-21 came out of the CIA sponsored A-12 program. For photo targets which were too sensitive or too far away for manned A-12 flights, the unmanned D-21 was developed. The D-21 was powered by a Marquardt RJ43-MA-11 ramjet, similar to the engine used on the Bomarc missile.
The original plan was to launch the D-21 from a M-21 mothership (a modified A-12), but the 4th test flight destroyed the drone and the mothership; and operationally the D-21B was dropped from a B-52H with a solid propellant booster to get the craft up to a speed where the ramjet could operate.