Lockheed D-21

Lockheed D-21. The Lockheed D-21 was an advanced, unmanned reconnaissance drone designed and built in absolute secrecy during the height of the Cold War. Developed by the famed Lockheed Skunk Works under the direction of Kelly Johnson, it was intended for deep-penetration surveillance missions over denied territories such as the Soviet Union and the People's Republic of China. Its operational career was brief and troubled, but it remains a significant and pioneering example of aeronautical engineering from the era.

Development and Design

The genesis of the D-21 program stemmed directly from the political fallout following the 1960 U-2 incident, where a Central Intelligence Agency Lockheed U-2 piloted by Francis Gary Powers was shot down over the Soviet Union. Seeking an invulnerable reconnaissance platform, the CIA and the United States Air Force commissioned the Lockheed Skunk Works to develop an unmanned vehicle. The initial concept, designated Tagboard, involved launching the drone from a modified, two-seat variant of the Lockheed A-12 Oxcart reconnaissance aircraft, known as the Lockheed M-21. The D-21's design was a marvel of its time, constructed primarily from titanium to withstand the intense heat generated by sustained Mach 3 flight. It was powered by a single Marquardt RJ43-MA-11 ramjet engine, which required a rocket booster for initial acceleration. Its Pratt & Whitney J58-powered mothership would accelerate to high speed before launching the drone, which would then fly a pre-programmed route over a target, eject its camera hatch for recovery, and self-destruct.

Operational History

Operational testing of the D-21/M-21 combination proved hazardous. During the fourth launch attempt in 1966, a D-21 drone collided with its M-21 mothership after launch, leading to the loss of the aircraft and the death of one of the crew members, Lockheed test pilot Bill Park. Following this catastrophic accident, the launch method was radically altered. The program shifted to using the Boeing B-52 Stratofortress as a carrier aircraft, with the drone, now designated D-21B, mounted on a pylon under the wing and launched using a solid-rocket booster. Four operational reconnaissance missions were flown over the People's Republic of China between 1969 and 1971 to monitor Lop Nur, the site of Chinese nuclear weapon tests. None were fully successful; three missions ended with the loss of the drone, and the film from the fourth was lost at sea during recovery. Facing high costs, technical failures, and the advent of a new generation of reconnaissance satellites, the program, known as Senior Bowl, was canceled in 1971.

Specifications (D-21B)

* **Primary Function:** High-speed, high-altitude reconnaissance drone * **Prime Contractor:** Lockheed Corporation * **Power Plant:** One Marquardt RJ43-MA-20S-4 ramjet (operational) and one Lockheed solid-fuel rocket booster (launch) * **Length:** 42 ft 10 in (13.1 m) * **Wingspan:** 19 ft 0 in (5.8 m) * **Height:** 7 ft 0 in (2.1 m) * **Launch Weight:** 11,000 lb (5,000 kg) * **Maximum Speed:** Mach 3.3+ (2,500+ mph; 4,000+ km/h) * **Service Ceiling:** 95,000 ft (29,000 m) * **Range:** 3,450 nmi (3,970 mi; 6,390 km) * **Guidance System:** Inertial navigation system * **Sensor:** Hycon optical camera

Legacy and Surviving Aircraft

Despite its operational shortcomings, the D-21 represented a bold leap in unmanned, high-performance aerospace technology. Its design and operational challenges provided invaluable data that informed later developments in stealth technology and unmanned aerial vehicles. Several D-21 drones survived the program's cancellation. Examples are displayed in major museums across the United States, including the National Museum of the United States Air Force at Wright-Patterson Air Force Base, the Museum of Flight in Seattle, the Pima Air & Space Museum in Tucson, and the Blackbird Airpark in Palmdale, California. Another is on display at the China Aviation Museum in Beijing, recovered from where it crashed in the 1970s. Its story is a testament to the ambitious, secretive, and technologically daring projects undertaken during the Cold War.

Category:United States reconnaissance aircraft Category:Unmanned aerial vehicles Category:Cold War reconnaissance aircraft of the United States Category:Lockheed aircraft