The Lockheed A-21 Blackbird was a mighty Mach 3.2 single seat reconnaissance spy plane built for the CIA which would later be developed into the two-seat Lockheed SR-71A Blackbird operated by the USAF. The A-12 first flew in 1962 and was operated from 1963 to 1968. It was powered by two Pratt & Whitney J58 afterburning engines
A variant of the A-12 was the Lockheed M-21 Blackbird. This was special variant operated by the USAF but built for the CIA “Tagboard“ program, where the M-21 acted as a mothership to launch the faster Lockheed D-21 ramjet powered, Mach 3+ reconnaissance drone for intelligence gathering.
2 M-21 aircraft were manufactured in 1963 and only 1 survives today. You can see this survivor today in the Great Gallery at Seattle’s Museum of Flight (it is on loan from the National Museum of the USAF).
The M-21 Blackbird had a special pylon fitted on its spine to carry and launch the D-21 drone (pictured) and had a second cockpit installed for the Launch Control Operator/Officer (LCO). This was a feature that was retained in the later SR-71A Blackbird to seat the Reconnaissance Systems Officer (RSO).
Once launched the D-21 drone was autonomous and would head to its programmed path to gather intelligence. It would then fly to a designated location to release its camera module with a parachute for mid-air collection by a specially equipped Lockheed C-130 Hercules. Once the data package was ejected the D-21 would self-destruct. This was all intended to avoid an incident of getting an aircraft shot down by a SAM over enemy territory like Francis Gary Powers in his U-2 over the Soviet Union on May 1st, 1960!
This all sounded fine in theory but in practice the program was fraught with danger and the program was cancelled following a 1966 collision between the drone and the tail of its mothership M-21 which resulted in a crash and the sad death of the Launch Control Officer. The D-21 program continued though and saw limited success being launched underwing from a Boeing B-52 Stratofortress bomber.
The D-21 drone / B-52 combination were operationally used on 4 occasions over China between November 1969 to March 1971 (codenamed “Senior Bowl”) but the program was cancelled in July 1971 due to a lack of operational success and the introduction of improved spy satellites. Of the 4 D-21 missions launched over China, the first did not turn around and self-destructed over Siberia in the Soviet Union; the second was successful but the parachute did not deploy properly over the recovery site and the camera module was lost at sea; the third mission was also successful but the aerial retrieval of the camera module was not successful and it was also lost at sea; finally the fourth mission failed when the drone crashed in China. 38 D-21 and D-21B drones were built with 21 launched on test and operational missions.