The AIM-7 Sparrow is an American, medium-range semi-active radar homing air-to-air missile operated by the United States Air Force, United States Navy and United States Marine Corps, as well as other various air forces and navies. Sparrow and its derivatives were the West's principal beyond visual range (BVR) air-to-air missile from the late 1950s until the 1990s. It remains in service, although it is being phased out in aviation applications in favor of the more advanced AIM-120 AMRAAM. The Self-Defence Forces of Japan also employ the Sparrow missile, though it is being phased out and replaced by the Mitsubishi AAM-4. NATO pilots use the brevity code Fox One in radio communication to signal launch of a Semi-Active Radar Homing Missile such as the Sparrow.
The Sparrow was used as the basis for a surface-to-air missile, the RIM-7 Sea Sparrow, which is used by a number of navies for air defense of their ships. Fired at low altitude and flying directly at its target though the lower atmosphere, the range of the missile in this role is greatly reduced. With the retirement of the Sparrow in the air-to-air role, a new version of the Sea Sparrow was produced to address this concern, producing the much larger and more capable RIM-162 ESSM.