US's D-21 Spy Drone: Mach 3.3 Speed, No Pilot, Cold War Secrets Revealed

• The Lockheed Martin D-21 was a supersonic spy drone developed by the US in the 1960s, capable of Mach 3.3 (3,200 km/h) without a pilot.
• It could fly at an altitude of 90,000 feet, had a range of 5,550 km, and was designed with stealth features, making it undetectable by radar.
• A D-21 crashed in China during a mission between 1969-1971, leading to its wreckage being recovered by China and shared with the Soviet Union.
• Both Russia and China attempted reverse engineering, gaining insights into advanced ramjet engine technology and radar-evading materials.
• The drone's mission was to photograph enemy nuclear sites, dropping its camera module for mid-air retrieval while the drone self-destructed.

Why It Matters: The D-21 was a revolutionary US spy drone, pushing technological boundaries and influencing Cold War espionage.