AGM-122 Sidearm
Main Points:
- Designed to meet Marine Corps requirement for an antiradiation missile to counter ground-based air defense systems.
- Used existing AIM-9C Sidewinder radar semi-active air-to-air missile with modified guidance section for detecting antiaircraft gun and surface-to-air missile radars
- Provided useful self-defense capability against low-level anti-helicopter threats.
The emergence of weapons such as the Soviet ZSU-23 antiaircraft guns and SA-8 surface to air missiles posed serious threats to U.S. helicopters. This generated a requirement by the Marine Corps to provide self-protection against these threats. China Lake engineers, along with industry partners Motorola answered this requirement by modifying a version of the Sidewinder missile that had a semi-active radar seeker on it. All but one version of the Sidewinder missiles were infrared-guided. However, one version, the AIM-9C was built with a radar seeker especially designed to provide the F-8 Crusader aircraft with an all-weather missile. No record exists as to the combat use of the AIM-9C, however, about 700 of the missiles were converted to the ASM-122 Sidearm for use on Marine Corps helicopters, A-4 Skyhawks, and AV-8 Harriers. The seeker electronics of the AIM-9C were modified to provide a greater bandwidth to home on a variety of threat radars. Control electronics were modified, but the Sidewinder motors and warheads were kept. Motorola carried out the remanufacture of the missiles. Between 1986 and 1990 about 700 missiles were provided to the Marine Corps. The missile was declared obsolete in 1998, but remains in inventory.
This is an excellent example of taking older technology, that had been phased out of the service and modifying it to meet a new threat.