The AGM-129 ACM (Advanced Cruise Missile) is the US Air Force's current nuclear-armed air-launched cruise missile used by the armed forces of the United States, replacing the earlier AGM-86 ALCM in that role. The AGM-129 includes a new inertial guidance system, a laser-based mapping system, and a number of stealth features to improve accuracy and penetration ability.
The ALCM relied entirely on its low-altitude flight for penetration, based on the Soviet Union's primarily ground-based defense system centered on surface to air missiles. In the early 1980s it became clear that they were starting to deploy a number of airborne early warning systems that would be able to "look down" and see the ALCM, allowing it to be attacked with ease. This included the new radar data networking capabilities of the MiG-31, which allowed several fighters to spread out and cover a wide area and attack the ALCM without external support.
The solution was to incorporate various "stealth" technologies into a new version of the basic ALCM system. These included changes to the body shaping to minimize radar reflections, moving the engine air intake to hide the compressor face (normally a major radar return) and even using a diffuser on the engine exhaust to minimize the infra-red signature. Another major change was the addition of a laser-based TERCOM terrain-following LIDAR to supplant the radar-based system of the original ALCM, to reduce or eliminate emissions.
* Span: 3.1 m
* Length: 6.35 m
* Diameter: 705 mm
* Weight: 1680 kg loaded
* Warhead: W80 nuclear - 5 to 150 kilotons
* Engine: Williams International 112 turbofan of 3.25 kN thrust
* Cruise speed: 800 km/h
* Range: 3000 km
