AGM-129 ACM
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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 US currently has a total of 460 ACMs.
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[edit] History
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.
These changes made the ACM much more difficult to find, so much so that the missile can be flown at higher altitudes. This, combined with a newer and more efficient Williams F112-WR-100 turbofan engine increased range by about 50%. Even with the increase in range the newer guidance system and the addition of a laser mapping system, increased accuracy to a quoted figure of between 30 m (100 ft) and 90 m (300 ft). It is armed, like the ALCM, with the W80 nuclear warhead.
Production was contracted to General Dynamics (now Raytheon) in 1983, and the missile first flew in July 1985. Production models started delivery in 1990, originally intending to deliver up to 2,500 for both the B-52 and B-1 fleets, but this was later scaled back to 1,460 to replace the existing ALCM's, then to 1,000 for the B-52 only. Production actually ended in 1993 after delivery of only 460.
[edit] Variants
There are rumors of an additional version of the ACM known as the AGM-129B. Confusion exists as to precisely how this weapon is different from the original. Gibson states that it is an AGM-129 "modified with structural and software changes and an alternate nuclear warhead for accomplishing a classified cruise missile mission." However, Ozu states the AGM-129B was intended to be a non-nuclear version of the ACM, much as the nuclear AGM-86 led to the conventional AGM-86C. Some reports claim that the AGM-129B was actually produced, others that it was cancelled before production began.
[edit] Specifications
The START II treaty, defunct since June 2002, had forbidden the USA from using stealth weapons on stealth aircraft. Because of their low radar signature, stealth bombers do not need to fire their weapons at standoff range, outside the reach of enemy air defenses. Although the capability still exists for these other aircraft, the ACM is only carried on the B-52H Stratofortress. There are 2 external mounts which gives the B-52 a 12 missile payload. Six missiles per external launcher. The B-52H can also carry up to 4 missiles in its internal rotating launch bay.
All figures listed reflect AGM-129, not "B"-variants
- Span: 3.1 m (10 ft 2 in)
- Length: 6.35 m (20 ft 10 in)
- Diameter: 705 mm (2 ft 5 in)
- Weight: 1680 kg (3,500 lb) loaded
- Warhead: W80 nuclear - 5 to 150 kilotons
- Engine: Williams International 112 turbofan of 3.25 kN (732 lbf) thrust
- Cruise speed: 800 km/h (500 mph)
- Range: 3000 km (1865 miles)
[edit] References
- Nuclear Weapons of the United States, James N. Gibson, Schiffer Publishing Ltd, Atglen, Pennsylvania, 2000 ISBN 0-7643-0063-6
- Missile 2000 - Reference Guide to World Missile Systems, Hajime Ozu, Shinkigensha, Tokyo, 2000 (Japanese)
- 2003-2004 Weapons File, United States Air Force, Eglin Air Force Base, 2003 [1]
