The Lockheed D-21 is an American supersonic reconnaissance drone. The D-21 was initially designed to be launched from the back of an M-21 carrier aircraft, a variant of the Lockheed A-12 aircraft. The drone had maximum speed in excess of Mach 3.3 at an operational altitude of 90,000 feet. Development began in October 1962. Originally known by the Lockheed designation Q-12, the drone was intended for reconnaissance deep into enemy airspace.
Lockheed D-21
Rear view of the D-21 and M-21 combination on the ground, showing the exhaust shroud used on early flights
M-21 carrying D-21 in flight
A modified D-21 carried on the wing of a B-52
An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs were originally developed through the twentieth century for military missions too "dull, dirty or dangerous" for humans, and by the twenty-first, they had become essential assets to most militaries. As control technologies improved and costs fell, their use expanded to many non-military applications. These include aerial photography, area coverage, precision agriculture, forest fire monitoring, river monitoring, environmental monitoring, policing and surveillance, infrastructure inspections, smuggling, product deliveries, entertainment, and drone racing.
Elbit Systems Hermes-450 taking off
Northrop Grumman Bat carrying EO/IR and SAR sensors, laser range finders, laser designators, infra-red cameras
A DJI Phantom quadcopter UAV for commercial and recreational aerial photography
A General Atomics MQ-9 Reaper, a hunter-killer surveillance UAV