drone

drone or remotely piloted vehicle, a pilotless craft guided by remote control. Aircraft, ships, and land vehicles can be designed or outfitted as drones, although underwater vessels—both piloted and pilotless—are usually called submersibles. Small, relatively inexpensive military drones are used as targets in combat practice, while high-performance models may be used in hazardous reconnaissance missions and to carry and launch missiles against enemy targets without exposing pilots and their far more expensive aircraft to antiaircraft fire. Depending on the mission, drones can be equipped with armament, radar, video cameras, lasers, or sensors for chemical or biological weapons. Guidance of the drone can originate from an airplane, a ship, a ground station, or a satellite link. Building upon the successful use of drones in the Second Persian Gulf War, the Homeland Security Department is planning to use unmanned aircraft to track drug smugglers, illegal immigrants, and terrorists along the U.S. borders. Contemplated civilian uses include replacing stationary video cameras and sensors for traffic control, for monitoring crops, to help fight forest fires, and for atmospheric research.

Early attempts to use unmanned aerial vehicles are documented as early as the U.S. Civil War. Both Union and Confederate troops launched balloons loaded with explosives in the hope that the balloons would come down inside ammunition or supply depots and explode, but the balloons were at the mercy of the prevailing winds and proved largely ineffective. Toward the end of World War II the Japanese launched similarly ineffective high-altitude balloons loaded with incendiary and other explosives in the hope that winds would carry them to the United States, where they would start forest fires. A U.S. project at about the same time, called "Operation Aphrodite," involved using a modified manned aircraft as a cruise missile. The pilot would take off, get the plane to altitude, pass control to a manned aircraft through a radio link, and then bail out. The somewhat more successful German V-1 was essentially an early cruise missile, not a remote-controlled drone. By the Vietnam War the technology to launch and control drones had evolved. Initially, pilotless aircraft equipped with video cameras flew over North Vietnam to provide reconnaissance data; drones were later used to drop leaflets, interfere with electronic communications, and locate surface-to-air missile batteries.