<text id=missile3><title>Silo-Launched and Cruise Missiles</title>
<history>US Air Force: Weapons</history>
<article><hdr>Silo-Launched and Cruise Missiles</hdr><body>
<hi style=hdr1>LGM-118 Peacekeeper</hi>
<p>Commonly known as <hi format=bold>MX</hi>, Martin Marietta's 195,000-lb LGM-118 was originally conceived as a mobile system to decrease its vulnerability to attack. The Peacekeeper is a four-stage missile which can deliver 10 500-kT warheads at intercontinental ranges. While several concepts were considered, a railroad-based system was eventually settled upon. A controversial system, development of the hardware proceeded faster than the political debate surrounding its basing. As an interim solution, 50 of the 100 authorized missiles were deployed beginning on 13 September 1986 with the 90th SMW, at F. E. Warren AFB, Wyoming, in former Minuteman III silos. The Peacekeeper began alert duties on 10 October 1986. The other missiles were stored as they were produced. Plans to develop the rail basing system were canceled in September 1991, in response to the dramatic changes in the world situation. President Bush announced cancellation of further production during his State-of-the-Union Address in January 1992 and proposed scrapping of existing missiles if the former Soviet Union would scrap their large, multiple warhead ICBMs. Current plans call for the LGM-118s to be retired between 2000 and 2004.
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<hi style=hdr1>LGM-30 Minuteman</hi>
<p>The Minuteman silo-launched, surface attack, guided missile (LGM)-30 has been operational for over 20 years. Built by Boeing, this solid-fuel, three-stage missile is named for the quickness of its response as much as the volunteer soldiers of the American Revolution. Ten missiles are controlled from each two-man command site.
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<p>First delivery of an SM-80 Minuteman IA (later HGM-80A) to an operational unit was on 27 July 1962 to the 341st SMW at Malmstrom AFB, Montana, becoming operationally ready on 11 December 1962 with the 10th SMS. The final LGM-30As stood down from alert with the 10th SMS on 15 January 1969.
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<p>First delivery of an HGM-80B Minuteman IB to an operational unit was on 20 April 1963 to the 44th SMW at Ellsworth AFB, South Dakota, becoming operationally ready in July 1963 with the 66th SMS. The final LGM-30Bs stood down from alert with the 320th SMS on 3 September 1974 at F. E. Warren AFB, Wyoming.
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<p>The 73,000-lb LGM-30F Minuteman II had a 6,000-nm (11,064-km) range and carried a single, 1.2-mT warhead. First delivery of an LGM-30 F to an operational unit was on 5 August 1965 to the 447th SMS of the 321st SMW at Grand Forks AFB, North Dakota, becoming operationally ready in January 1966. These 450 missiles stood down from alert during September 1991 as part of a US initiative to reduce nuclear tensions.
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<p>The 78,000-lb LGM-30G Minuteman III has a 7,000-nm (12,908-km) range and carries three 335-kT warheads. First launched in 1968, initial delivery to an operational unit was on 14 April 1970 to the 91st SMW at Minot AFB, North Dakota, becoming operationally ready with the 741st SMS on 19 August 1970. Fifty of the original force of 550 were been replaced by the LGM-118, with the remainder staying operational. However, during his January 1992 State-of-the-Union Address, President Bush announced plans to remove two of each missile's three warheads.
<p>Boeing's Air Launched Cruise Missile (<hi format=bold>ALCM</hi>) was initially envisioned as a replacement for the ADM-20 Quail decoy missile and called subsonic cruise armed decoy (<hi format=bold>SCAD</hi>). It was finally developed as the <hi format=bold>AGM-86A</hi> to be a long-range complement for the AGM-69 SRAM, with which it had launcher compatibility. The length of the AGM-86A was defined by the length of the B-1A's weapons bay. After cancellation of the B-1A, the AGM-86 was redesigned prior to competing against the AGM-109H Tomahawk to see which missile would arm the B-52G. Called <hi format=bold>AGM-86B</hi>, the new missile had a longer fuselage, since it would only be used with the B-52. First delivered to the 416th BMW at Griffiss AFB, New York, on 11 January 1981 (where it began alert duties on 16 December 1982), ALCMs were equipped with the 200-kT W80-1 warhead. The 3,200-lb AGM-86B is a subsonic, turbojet-powered missile with a range in excess of 1,500 nm (2,775 km). As B-52Gs were withdrawn from service, B-52Hs became ALCM carriers. Although the B-1B was designed with ALCM carriage in mind, it was never used in that role operationally.
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<p>The most interesting aspect of cruise missiles is their guidance system. Although the altitude flown is controlled by a radar altimeter, the clearance level commanded varies during the mission, depending on terrain, so the missile flies just high enough to avoid hitting terrain rising faster than the radar altimeter and flight controls can compensate for. The flight path is painstakingly planned to pass over several areas of distinctive terrain. The relative elevations of these areas are stored in the navigation computer. As the missile flies over an area, it compares the actual radar readings with those in the computer and uses this information to update its inertial navigation system. Early in the flight, these areas are fairly large, but, as the mission progresses, get progressively smaller and more accurate. This type of guidance system can be frighteningly accurate, but requires extensive, painstaking mission planning.
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<p>It was revealed a year after the Gulf War that seven B-52Gs fired 35 <hi format=bold>AGM-86C</hi> conventional ALCMs (<hi format=bold>CALCM</hi>) against eight targets in northern Iraq, including hydroelectric and geothermal power plants near Mosul, and the telephone exchange in Basara. The announcement of this attack provided the first public knowledge of this previously secret ALCM variant, which began development in July 1986 as a result of requirements generated in the wake the Libyan bombing raid the previous April. The classified codename for the program was Senior Surprise, although the crews called them 'Secret Squirrels'.
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<p>Flight testing began in August 1987, with the CALCM being declared operational in January 1988. Planners referred to the missiles as extra long range bombs (<hi format=bold>XLRB</hi>) to maintain the secret of their existence for as long as possible. The modifications to each of the 'more than three dozen' AGM-86Cs cost $380,000 per missile and included a 1,000-lb blast-fragmentation warhead and incorporation of GPS guidance. The latter feature vastly simplifies mission planning requirements and increases flexibility by enabling missions to be planned over featureless terrain like that found in Middle Eastern deserts. Most of the CALCMs were expended during the Gulf War missions, but more were modified after the war. By September 1994, consideration was being given to equipping CALCMs with carbon fiber warheads like those used by BGM-109s during Desert Storm and electromagnetic pulse (EMP) generator warheads. The latter would produce a momentary burst of microwave energy to disable electronic devices associated with enemy command and control facilities.
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<p>Escalating costs of the AGM-137 led to its cancellation in February 1995 and consideration of buying more AGM-86Cs, -130s, and/or -142s. The CALCM option is favored by some because those missiles have already been paid for and are available because of their disappearing nuclear attack role.
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<hi style=hdr1>AGM-88 HARM</hi>
<p>Based on lessons learned in Vietnam, the 800-lb class AGM-88 High-Speed Anti-Radiation Missile (<hi format=bold>HARM</hi>) is fast enough to give SAM operators minimum opportunity to shut down their radar before the HARM does it for them. HARM has three modes of employment. In the <hi format=bold>prebriefed</hi> mode the missile is programmed on the ground for up to three specific missile sites. Upon detecting one of the sites, it is launched on a ballistic trajectory towards it. Although HARM can be launched in the direction of a target, it guides in azimuth only, not range, thus relying on the target to emit and identify itself. The <hi format=bold>self-protection</hi> mode launches the missile against threats detected by the launching aircraft's radar warning receiver. The <hi format=bold>target of opportunity</hi> (<hi format=bold>TOO</hi>) mode uses the HARM's seeker to help determine when to launch against a previously unknown threat. One interesting technique used during the opening stages of the Gulf War was to use BQM-74C targets and ADM-141 TALDs as decoys. They enticed the SAM sites into turning on their radars for an incoming barrage of HARMs.
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<p>There are three versions of the AGM-88, differing mainly in the features of the guidance section electronics. All versions use BSU-59 wings, BSU-60 tail fins, a YSR 113-TC-1 64,000 lb-second total impulse rocket motor, a WCU-2 control section (with DSU-19 pulsed laser, proximity/contact target detector), a WAU-7 146-lb blast fragmentation warhead (AGM-88A and B only) and different versions of the WGU-2 guidance section. The missiles are overall FSN 36622 gray with a 2-in (5-cm) FSN 23538 yellow band two in behind the front edge of the warhead and a 2-in FSN 20117 brown band two in behind the front edge of the motor.
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<p><hi format=bold>Block I</hi> seekers require the seeker to be sent back to a depot in the US to be reprogrammed using hardware changes. The <hi format=bold>Block II</hi> seeker introduced electronically erasable/programmable read only memory (EEPROM) which allowed the seeker to be reprogrammed on the flight line. <hi format=bold>Block III</hi> is essentially a new software program for the Block II hardware that is installed during depot maintenance (Block I seekers were not upgraded because it would have required a major hardware modification). The <hi format=bold>AGM-88A</hi> used both Block I & II seekers. The <hi format=bold>AGM-88B</hi> used both Block II & III seekers. The Block III AGM-88B was the main version used during the Gulf War, and its reprogramming capability was used on both USAF and USMC missiles. The <hi format=bold>Block IV AGM-88C</hi> entered service in early-1993. In early 1994, software changes to the aircraft-mounted command launch computer (CLC) were released to take advantage of the Block IV missile's seeker ability to self-guide in the TOO mode. The Block IV incorporates a doubling of seeker range, improved performance against frequency agile radars, and replacement of the steel cubes in the warhead with considerably more lethal tungsten alloy ones.
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<p>Texas Instruments was contracted to produce 2,041 AGM-88Cs to replace HARMs expended during the 1991 Gulf War (USN A-6E, EA-6B, A-7E, and F/A-18 aircraft launched 661 HARMs, while USMC EA-6B and F/A-18s launched 241, and USAF F-4G and F-16Cs launched about 1,100). The TI seeker, known as the AGM-88C-1 completed testing before a proposed competitor, Loral's AGM-88C-2 low-cost seeker was ready to enter testing. In addition, the Navy acquired 624, and the Air Force 750, new seekers to upgrade Block III missiles during FY94 and FY95. This brings HARM production totals to approximately 21,000 (plus another 1,000 guidance head retrofits). There were no plans to export Block IV missiles.
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<p>The USAF only employs HARM from F-4Gs and F-16C 'Wild Weasels', launching them from the <hi format=underline>LAU-118(V)2A</hi> launch rails (modified from LAU-34s), that can also launch the older AGM-45. The F-4G is by far the HARM's most effective launch platform because its APR-47 system allows it to detect, identify and precisely locate threat radars, then attacking or directing other aircraft to attack them. Passing consideration was given to arming EF-111As with HARM, but this would have required rewiring its wing stations. The AGM-88B has been exported to Germany and Italy (Tornado ECRs), Australia (F-111C), Spain (F/A-18), South Korea and Turkey (F-16).
<p>Intended as a stealthy replacement for the AGM-86B, the ACM first flew in July 1985, with deliveries of production AGM-129As beginning in June 1990. Built by General Dynamics (now Hughes), the 2,750-lb ACM has a range of more than 1,800 nm (3,320 km) and features improved accuracy and targeting flexibility, but the same W80-1 warhead as the AGM-86. About 640 missiles were under contract, with plans for 1,461 missiles to arm B-52Hs, when President Bush announced cancellation of further production during his State-of-the-Union Address in January 1992. Due to cost overruns and funding cuts, the final number actually built was only 461. Operational training launches began during 1991, and there are no plans to integrate the missile with any other airframes.
