The Sidewinder AIM-9 is one of the oldest, least expensive, and most successful missiles in the U.S. weapons inventory, and it is perhaps the most widely used air-to-air missile in the West, used by 27 nations other than the United States and in every conflict since the 1950s. A supersonic, short-range, air-to-air missile carried by fighter aircraft, it has four main components: an infrared homing guidance section, an optical target detector, a high-explosive warhead, and a single-stage solid-propellant rocket motor. Its infrared guidance section enables it to home in on the engine exhaust of target aircraft, allows day-or-night use in all weather conditions, and lets a pilot launch the missile and then leave the area while it guides itself to the target. Development began in 1949 at the U.S. Naval Weapons Center at China Lake, California, where the need was for a simple heat-seeking air-to-air missile for naval interceptor aircraft, which until then had been armed with either .50 cal or 20 mm guns. The result was a compact, lightweight, cruciform canard weapon named for the Sidewinder, a desert rattlesnake that detects its prey by sensing heat emissions. A prototype, the AIM-9A, was first tested in 1951, and on September 11, 1953, it scored the first air-to-air hit on a drone. The initial production version, designated Sidewinder AIM-9B, entered U.S. Navy service in 1956, and many operational versions later followed for Navy and Air Force fighter and attack aircraft. Closely related missiles are the Air Force's Falcon and the Army's Chaparral, a surface-to-air missile. At White Sands, the first Sidewinder was launched in 1955, and firing records show that between 1955 and 1959, 191 Sidewinders were fired there.