The AIM-9 "Sidewinder" is a heat-seeking, short-range, air-to-air missile carried by wide range of modern tactical aircraft in the U.S. military and recently, certain gunship helicopters. The AIM-9 is one of the oldest, least expensive and most successful missiles in the U.S. weapons inventory. A prototype of the Sidewinder, the AIM-9A, was first fired successfully in September 1953. The initial production version, designated AIM-9B, entered operational use in 1956 and has undergone multiple upgrades and improvements. After more than five decades in active service, upgraded "Sidewinder" missiles remain the most widely used air-to-air missile employed today; more than 40 nations throughout the world use the "Sidewinder". About 110,000 Sidewinders have been built, of which perhaps one percent have been used in combat, resulting in some 250-300 kills worldwide to date.
