v2.0.3 / chapter 4 of 7 / 01 feb 07 / greg goebel / public domain
* While the attempts to build cruise missiles during World War II and in the immediate postwar period were not generally successful, by the 1970s the technology was available to do the job right. The results were first really practical cruise missiles, the "Air-Launched Cruise Missile (ALCM)", and the "Sea-Launched Cruise Missile (SLCM)" or "Tomahawk". This chapter discusses the ALCM and SLCM.
* Modern cruise missiles were derived from technologies developed in the early 1960s. The most important of these technologies were compact, lightweight, powerful turbofan engines. In 1962, Dr. Samuel Williams and his Williams Research company introduced a small turbojet, the "WR-2", that could produce 0.31 kN (32 kgp / 70 lbf) of thrust. It was nothing particularly new, small turbojets having been built by other firms for over a decade, but in 1964, Williams Research proposed to build an advanced small turbofan engine to power a "flying belt" for infantry use. The result, the "WR-19", was introduced in 1967. It was 30.5 centimeters (1 foot) in diameter, 61 centimeters (2 feet) long, weighed 31 kilograms (68 pounds), and generated 1.9 kN (195 kgp / 430 lbf) of thrust, ten times the thrust-to-weight ratio of any engine previously built in that size class.
While the flying belt schemes didn't work out, the WR-19 impressed the military, and the small Williams Research jet engines seemed very promising as powerplants for drones and missiles.
In the meantime, the US military had been enjoying significant success with robot aircraft in air operations over Vietnam. The Ryan Firebee drone, developed in the 1950s, was used in over 3,400 reconnaissance and other missions with a high success rate, with the drones controlled by increasingly capable and accurate guidance systems.
Another extremely important technology for the development of cruise missiles were nuclear warheads light enough to be carried on a small robot aircraft. Not only had an engine become available for a small cruise missile, the guidance systems to make them reasonably accurate weapons and a warhead to make them dangerous had also come into being.
* The first steps towards the development of the modern cruise missile were two projects considered by the USAF, the "Subsonic Cruise Unarmed Decoy (SCUD)" and "Subsonic Cruise Attack Missile (SCAM)", to be powered by the WR-19 or a derivative. The Air Force finally settled on a concept named the "Subsonic Cruise Armed Decoy (SCAD)", a contract for which was awarded to Boeing in 1970. SCAD was to be propelled by a WR-19 derivative called the "F107", and would have a range of about 1,200 kilometers (750 miles). It could be configured either as an unarmed decoy or attack weapon, with the idea being to saturate and confuse Soviet defenses. SCAD certainly succeeded in causing confusion in the Air Force and the service's political overseers. The USAF feared that it would undermine support for their manned bomber fleet and did everything they could to emphasize "Decoy", instead of "Armed".
The SCAD had to be compatible with the existing rotary SRAM launcher carried in the bombbay of the B-52. This restricted the weapon's length, and so its range. It also dictated that it have a trapezoidal cross-section, to allow the missiles to be nested together, as well as a "duck-bill" nose to allow it to clear the launcher. Of course, it had to have folding wings.
Weak commitment and rising program costs finally killed off SCAD in the summer of 1973. The program was almost immediately revived as the "Air-Launched Cruise Missile (ALCM)", which was purely an attack missile, not a decoy. The reason for this abrupt about-face was that the project had become attractive as a bargaining chip in the Strategic Arms Limitation Talks (SALT II). The Air Force might have wanted a decoy, but ended up deciding that a weapon would be preferable, since it could be used to get political leverage against the Soviets.
In the meantime, the Navy had been working with General Dynamics on a cruise-missile concept of its own, called the "Submarine-Launched Cruise Missile (SLCM)" that could be launched out of a torpedo tube. This would eventually become the "Tomahawk" cruise missile, and is discussed later. The ALCM and SLCM had much in common, and so the Pentagon decided to leverage technologies between the two. Both missiles would end up having a terrain-following guidance system and a Williams Research F107 turbofan engine, with 2.65 kN (270 kgp / 600 lbf) thrust, though each type of missile would have different versions of the guidance system and engine.
Boeing produced the first version of the ALCM, the "AGM-86A", where AGM stood for "Air to Ground Missile", with first test flight in 1976. There were many failures, but eventually the bugs were worked out. However, in 1977, the government announced that there would be a competitive fly-off between the Boeing AGM-86 design and another ALCM based on the SLCM, the "AGM-109", in 1979.
This led to rethinking the AGM-86 project. The USAF had given ALCM low priority, and in fact there were many Air Force brass who had a low opinion of the whole idea of cruise missiles. The problem was that Congress was more enthusiastic, and the competition put Air Force leadership in the position of either developing an ALCM themselves or accepting whatever the Navy developed. The Air Force of course backed the Boeing design.
* One of the most significant drawbacks of the original AGM-86A was its relatively short range, limited by the requirement that the missile fit into the existing B-52 SRAM launcher. The decision was made to abandon SRAM capability, and so Boeing came up with a new version of the ALCM, the "AGM-86B", that was 30% longer, giving it greater fuel capacity and longer range. The new missile could be carried on the underwing pylons of a B-52, but not on the bombbay rotary SRAM launcher.
The fly-off between the Boeing AGM-86B and the GD AGM-109 duly took place in 1979. Both weapons performed poorly in tests: out of ten flights apiece, four of each crashed, and there were a number of other problems and failures. In 1980 the USAF went ahead selected the AGM-86B anyway, and the first production missiles were shipped to B-52 squadrons in 1981.
The ALCM is powered by a Williams Research F107-100 engine, and carries a
W-80 nuclear warhead with 200 kilotonnes yield, as developed for SRAM. ALCM
is guided by a INS and a "Terrain Contour Matching (TERCOM)" navigation
system. TERCOM uses a downward-pointing radar altimeter to determine the
missile's altitude as it flies towards a target, and compares the ground
elevation profiles with maps stored in memory to determine if the missile is
on course. The fact that the radar altimeter points straight down ensures
that the missile doesn't give itself away by its radar emissions, but since
the missile flies at low altitude, mission planners must ensure that it
climbs when the TERCOM maps predict a cliff is ahead.
BOEING AGM-86B ALCM:
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spec metric english
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wingspan 3.7 meters 12 feet
length 6.3 meters 20 feet 8 inches
total weight 1,450 kilograms 3,200 pounds
speed subsonic
range 2.500 kilometers 1,550 MI / 1,350 NMI
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A total of 1,715 AGM-86Bs were built, with final deliveries in 1986. They
were carried on the underwing pylons of B-52s, with each pylon carrying two
tandem clusters of three missiles, for a total of 12 missiles. In 1986,
Boeing also began modifying B-52s to carry eight ALCMs in a
specially-designed rotary launcher in the bombbay, for a total load of 20
ALCMs.
* The arms limitations treaties signed by the United States and the Soviet Union in the late 1980s singled out ALCMs for elimination as nuclear weapons, but allowed for their conversion to conventionally-armed missiles.
The US Air Force had begun development work on a "Conventional ALCM (CALCM)" variant back in 1986, after US air attacks on Libya in 1985 codenamed Operation EL DORADO CANYON. Flight tests of the AGM-86C CALCM began in 1987. The program was kept secret, since CALCMs seemed likely to be a useful weapon in the limited combat operations in which the US military was increasingly involved, and there was no reason to let potential enemies know what tricks the USAF might have in store for them. CALCMs were referred to as "Extra Long Range Bombs (XLRB)" in documents to help keep the secret. The program was codenamed SENIOR SURPRISE, though flight crews called the CALCMs "Secret Squirrels", after a super-spy cartoon character.
A small number of "Block 0" CALCMs were initially produced. While it appears that they were conversions from ALCMs, some sources also mention new production CALCMs. Due to the secrecy surrounding the program, estimates of CALCM inventories and production are uncertain.
The CALCMs had reduced fuel tankage to help accommodate a large 900 kilogram (2,000 pound) blast-fragmentation warhead, and were also fitted with a "Global Positioning System (GPS)" navigation system. The warhead sprays a cloud of ball bearings and is optimized for dispersed, relatively unprotected targets such as surface-to-air missile (SAM) batteries.
CALCM was still secret during the Gulf War in 1991, while the Navy got all the publicity for introducing their Tomahawk cruise missile to combat. CALCM was actually used in the Gulf War, but this was not publicly revealed until 1992, when the Air Force reported that seven B-52Gs had fired 35 CALCMs at eight targets in northern Iraq. This expended almost all the Air Force's inventory of CALCMs, but the service quickly arranged for further production.
Later production AGM-86Cs were in a "Block 1" configuration, with a larger blast-fragmentation warhead weighing 1,360 kilograms (3,000 pounds). The Block 1 CALCMs also had an improved GPS guidance system that cut their "circular error probability (CEP)" in half, meaning they were twice as accurate. It seems likely that the larger warhead was obtained by further reducing fuel capacity, but the Block 1 CALCM still has a range of 1,200 kilometers (745 miles).
Even with the larger Block 1 warhead, CALCM was unsatisfactory for attacks on hard targets, and so in 1998 the USAF began evaluating two different hard-target penetrating warheads, the Lockheed-Martin "Advanced Unitary Penetrator (AUP)" and the British Aerospace "Multiple Warhead System (MWS)". Tests firings were performed on both warheads. An AUP fired in July 1999 punched through 3 meters (10 feet) of dirt, 1.5 meters (5 feet) of reinforced concrete, and then continued downrange for over 1,200 meters (4,000 feet). The AUP uses kinetic energy and a hard case to penetrate, and has a "Hard Target Smart Fuze" to allow it to allow it to detonate at a preselected point within the target. The MWS uses a two-stage warhead, based on a British Aerospace design known as "Broach". The first stage of the warhead blasts away soil, clearing the way for a kinetic energy penetrator.
The USAF incorporated an unspecified hard target warhead in the 50 of the last batch of CALCM conversions, performed by Boeing in 1999 and 2000 after operations in the Balkans. CALCMs fitted with the hard target warhead are designated "Block 1A".
* Even as the ALCM was being introduced to service, the US Air Force was working on a next-generation cruise missile. General Dynamics began work on what would be the "AGM-129 Advanced Cruise Missile (ACM)" in 1983, with first deliveries in 1987. Both an "AGM-129A" and a specialized "AGM-129B" variant were produced.
Production contracts were awarded to both General Dynamics and McDonnell Douglas through a second-source arrangement. Although 1,461 missiles were planned, only 450 were built due to rising costs and funding restrictions. Twelve ACMs can be carried on a B-52H's external pylons.
The ACM was intended to provide longer range, more sophisticated guidance, and greater stealth than ALCM for the nuclear strike role. The ACM is a sleeker weapon than the ALCM and more exotic in appearance. Its pop-out wings are forward-swept, apparently as a stealth measure, making it one of the few flying machines with forward-swept wings to achieve operational status. The tailplane is also forward swept, while the ventral tailfin is backward swept.
The ACM's fuselage is a streamlined spindle. The air intake is set flush
into the missile's belly beneath the wing, and the exhaust is nocked into the
end of the spindle just behind the tailfin. It is powered by a Williams
Research F112-WR-110 turbofan engine with 4.0 kN (408 kgp / 900 lbf) thrust.
GENERAL DYNAMICS AGM-129 ACM:
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spec metric english
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wingspan 3.13 meters 10 feet 3 inches
length 6.35 meters 20 feet 10 inches
total weight 1,250 kilograms 2,750 pounds
speed subsonic
range 3,330 kilometers 2,070 MI / 1,800 NMI
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The AGM-129A is armed with the same 200 kilotonne W-80 warhead as the ALCM.
Some reports hint that the AGM-129B has a conventional warhead, though other
reports indicate it has a specialized nuclear warhead, possibly a penetrating
munition for attacking "hard" targets such as underground command centers.
* As a footnote to the ACM effort, Lockheed developed and test-flew their own missile design, codenamed "Senior Prom", for the program. Little or no information was available on Senior Prom until 2005, when a set of photos and some data were released. The Senior Prom demonstrators had "faceted" airframes, giving them a certain general resemblance to the Lockheed F-117 Stealth Fighter, and were launched from Lockheed DC-130 Hercules drone controller aircraft. There were 13 test flights in 1979 or 1980 through 1981. The Senior Prom was also considered for the reconnaissance role and there may have been some further development of the concept after General Dynamics won the ACM competition.
* The US Navy initiated development of what would become the Tomahawk SLCM in 1972, after deciding that the service needed a robot weapon that could fly under enemy radar and perform a precision strike on heavily-defended fixed "hard targets". Since the Navy did not have a long-range strategic bomber force, the new cruise missile did not really compete with existing Navy assets, and the Navy was much more enthusiastic about SLCM than the Air Force was for ALCM.
The Navy wanted to be able to fire the missile out of a torpedo tube, which restricted its length to 6.25 meters (20 feet 6 inches), its diameter to 53 centimeters (21 inches), and its weight to 1,910 kilograms (4,200 pounds). The weight limitation was imposed by the lifting capability of torpedo handling equipment. The weapon was named "Tomahawk".
Both nuclear and conventionally armed versions were specified. By late 1973, the Navy had narrowed down the competition to two contenders, the General Dynamics "BGM-109" and the Ling-Temco-Vought (LTV) "BGM-110", where BGM stood for "Boosted Guided Missile". The Navy conducted a fly-off between the two missiles in 1976, and the General Dynamics BGM-109 was the winner.
The GD BGM-109 was externally similar to the LTV BGM-110, which was no great surprise since both were designed to be launched from torpedo tubes and necessarily looked like torpedoes. Their detail design was very different, however. The BGM-109 used pop-out wings; flat tail surfaces that folded out; and a Williams Research engine. The BGM-110 used a one-piece wing that pivoted out from the fuselage; curved tail surfaces that unfolded from a ring around the tail of the missile; and a Teledyne engine. The BGM-109 was judged a bit more conservative and a safer bet.
The first launch of a Tomahawk from a surface ship took place in 1980. Since the Navy had decided to use cruise missiles from surface ships as well as submarines, the acronym SLCM was redefined to mean "Ship Launched Cruise Missile". The Tomahawk became operational in the early 1980s, and equipped US Navy attack submarines; SPRUANCE class destroyers and TICONDEROGA class cruisers; and, while they were still operational, the four IOWA class battleships that were nostalgically refurbished for combat during the Reagan Administration.
* The Navy fielded four types of Tomahawks:
Each of these four types was built in two subvariants, one for surface launch and the other for submarine launch. For example, the surface launched subvariant of the BGM-109A was the "BGM-109A-1" (later "RGM-109A"), while the submarine launched subvariant was "BGM-109A-2" (later "UGM-109A", where "U" stands for "Underwater".) Tomahawks were built in various blocks. There are basically three blocks, "Block 1" through "Block 3", with a number of sub-blocks. Details are discussed in the next section.
* Along with the Navy Tomahawks, as mentioned, General Dynamics developed a similar air-launched AGM-109 that lost the Air Force fly-off with the AGM-86B. General Dynamics also built a nuclear-tipped "Ground Launched Cruise Missile (GLCM / Glickem)" variant for the USAF, known as the "BGM-109G Gryphon", which was very similar to the Navy nuclear BGM-109A variant. It differed from the Navy variant mainly in the use of a different W-84 warhead and enhanced self-test capabilities.
The Gryphon was launched from a large wheeled tractor-trailer rig known as a "Transporter Erector Launcher (TEL)". The big tractor unit was built by MAN Diesel of Germany, and it pulled a trailer that carry and fire four missiles from a large box that pivoted up from the rear of the trailer bed. The project was initiated in 1977; first flight tests of the GLCM were in 1980, with first launch from a TEL in 1981.
The GLCM was built in response to the Soviet SS-20 missile, which was a mobile weapon with three warheads that the USSR had deployed in numbers in Eastern Europe during the late 1970s. 464 production GLCMs were built and were deployed to Europe beginning in 1983 to sites in Belgium, Sicily, the UK, and West Germany. In a time of crisis the TELs were to be driven to predesignated sites and camouflaged; they were accompanied by a convoy of support vehicles, including trucks carrying security teams, with the convoy amounting to about 20 vehicles. If push came to shove, navigation and targeting information would be downloaded into the missiles and two officers would jointly perform the authentication procedure for launch. The missiles would fly at high altitude over "friendly" territory and then descend to low altitude for penetration into Warsaw Pact airspace.
There were loud public protests in many countries over the GLCMs, most particularly at Greenham Common in the UK, where a group of protesters set up a camp and engaged in a wide range of amusing theatrics. The vehicles had to be "protestor proofed", with screens installed in the gas caps to prevent foreign objects from being dumped into the fuel tanks, and parts of the vehicles had to be protected as best as possible from paint bombs and other annoyances. The protests never got out of control, nobody ever got seriously hurt, and in the end it all ended well.
After several years of tough negotiations, in 1987 the US and the Soviet Union signed the "Intermediate-Range Nuclear Forces (INF)" treaty, which required both sides to withdraw forward-based nuclear armed missiles from Europe and destroy them. The GLCMs were pulled out of Europe beginning in 1988, and were subsequently destroyed, while the Soviets pulled their SS-20s out and destroyed them as well. The treaty allowed salvage of their engines and guidance systems for conventionally armed Tomahawks; eight GLCMs were also disarmed and reserved for use as museum displays as permitted under the treaty.
* While air-launched AGM-109 Tomahawk never entered production, Hughes did promote an air-launched derivative known as the "AirHawk" for the British "Conventionally Armed Stand Off Missile (CASOM)" competition in 1995. Exactly what relationship Hughes had with General Dynamics at the time is difficult to determine, given the extremely confusing reshufflings of US defense contractors in the 1990s.
The AirHawk was about 43 centimeters (17 inches) shorter than the Tomahawk, had a third of the range due to smaller fuel capacity, and a new warhead. Hughes offered an even shorter version of the AirHawk for the US "Joint Air to Surface Standoff Missile (JASSM)" program (discussed in the next chapter), but there were no takers, and the AirHawk never went beyond the mockup stage. However, cancelled weapon systems have a odd way of being resurrected, so the idea may resurface in the future.
* All Tomahawk variants have the same basic configuration, but they vary in
guidance system and warhead. Wings pop out from the body, and due to stowage
issues one wing is mounted higher on the fuselage than the other. There are
four control fins that fold out from the tail of the fuselage. There are no
control surfaces on the wings.
GENERAL DYNAMICS TOMAHAWK TLAM-C:
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spec metric english
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wingspan 2.67 meters 8 feet 9 inches
length no booster 5.54 meters 18 feet 3 inches
length with booster 6.25 meters 20 feet 6 inches
total weight 1,500 kilograms 3,300 pounds
warhead weight 450 kilograms 1,000 pounds
speed 885 KPH 550 MPH / 480 KT
range 1,120 kilometers 700 MI / 610 NMI
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Weight varies slightly between Tomahawk versions. For example, submarine
launched variants weigh about 36 kilograms (80 pounds) more than surface
launched variants, due to the addition of waterproofing hardware and a
pressure venting system. The missile is stored on board ship in a 400
kilogram (900 pound) sealed stainless steel handling capsule for submarine
use, and a lighter aluminum capsule for surface ships.
All variants are powered by the Williams Research F107-WR-400 with 2.94 kN (300 kgp / 660 lbf) thrust. High-energy TH-dimer fuel is used instead of JP-5, which buys the missile about an extra 200 kilometers (125 miles) of range. The fuel is divided among several tanks to ensure flight trim.
When launched from a submarine, the missile is loaded into a torpedo tube inside its capsule. The Tomahawk is then ejected from the capsule and the torpedo tube by water injected through the rear of the capsule, which forces the missile through a diaphragm in front. A lanyard-tripped switch tells the missile when it has separated from the capsule. A moment later, the guidance system determines if the missile has the right attitude and velocity and fires the solid-rocket booster. For launch from a surface vessel, the missile is blasted from a box launcher or, increasingly, vertical launch silo on its booster. Once the Tomahawk is into the air, it jettisons covers from the turbofan engine inlet and the folded wing slots, as well as a fairing between missile and booster.
For the first few instants of flight, the missile is controlled by four vanes in the booster rocket exhaust. The booster burns for a total of about 12 seconds. Then the four tail-control fins take over, rolling the missile into a wings-level attitude. The wings pop open while the booster is still firing, generating lift so the missile can move out on a flatter trajectory to avoid detection. When the booster burns out and falls away, the turbofan inlet pops open and cruise begins at an altitude of 60 meters (200 feet). The low altitude and small size of the missile make it difficult to detect on radar, and its small engine is quiet and has a low infrared signature. Radar absorbing materials are used in projecting parts like the air inlet.
The navigation system, as mentioned, depends on the variant. The TLAM-N strategic nuclear variant provides a baseline. Initial navigation is by an INS, which guides the weapon to land. Once the missile is over land, a TERCOM terrain following system largely identical to that used in ALCM is used to guide the missile to the target.
TERCOM provides sufficient accuracy for a nuclear strike, but the conventionally armed TLAM-C and TLAM-D missiles require greater accuracy to be effective. They retain the INS and TERCOM system used on the TLAM-N, but have an additional "terminal guidance" system for precision targeting, known as "Digital Scene Matching Area Correlator (DSMAC)". DSMAC features an electronic camera in the nose of the missile that provides an image to a digital processor, which matches it to preprogrammed target features. Although some care must be taken to program the processor to recognize unique and unchanging features, accuracy is potentially extremely high. A strobe flash is also provided along with the camera to help with targeting on night flights.
The conventional warhead TLAM-C has three terminal attack modes:
The ship attack TASM variant has an INS, but no TERCOM, since it is meant to attack targets at sea. The INS takes the missile to the target area, where it then flies a winding search pattern, looking for a target. It recognizes the target with two different "seekers", one that performs active radar homing and the other that passively senses radar emissions from the target. The targeting system does not have any "identification friend or foe (IFF)" capability, and so no friendly vessels can be in the target area. Once the TASM identifies a target, it then attacks it. It can either strike the target broadside, or execute a last minute "pop up" and dive down on the deck.
* The TLAM-N strategic nuclear variant is armed with the same W-80 warhead used on ALCM. The TLAM-N is the lightest of the Tomahawks, and has the longest range, of up to 2,400 kilometers (1,500 miles).
Both the conventional TLAM-C and the ship-attack TSAM use the same conventional unitary warhead, the 450 kilogram (1,000 pound) WDU-25B semi-armor piercing warhead, developed for the USAF's Bullpup-B missile in the 1950s. The warheads appear to have been salvaged from scrapped Bullpup-Bs. Due to the bigger warhead, the TLAM-C is the heaviest of the Tomahawks and its range is cut to 1,120 kilometers (700 miles). However, the TSAM has the shortest range, 480 kilometers (300 miles), since it has to spend much of its time shuttling around in the target area in a search pattern.
The TLAM-D, with its cluster munition warhead, is most similar to the TLAM-C and has similar range. Instead of a unitary warhead, however, it is armed with a dispenser system carrying 166 "BLU-97/B Combined Effects Munitions (CEMs)", fired out the sides of the nose after panels are blown off. Each CEM is about the size of a soft-drink can, and weighs about a kilogram and a half (3.4 pounds). It is stabilized by a cloth strip on the tail, has a hollow-charge anti-armor explosive core that blasts forward, a fragmenting body, and a zirconium incendiary ring. The TLAM-D can dispense the CEMs in batches, allowing the missile to hit multiple targets, and then fly on to act as a decoy or crash into a soft target and destroy it by impact.
* As mentioned, Tomahawks were produced in three major blocks:
Block 3 also provided an improved mission planning support system. Programming Tomahawk's guidance system before launch is difficult and time-consuming, and the Block 3 system greatly automated and streamlined the process. In addition, the Block 3 TLAM-C was given an improved and lighter WDU-36B warhead, weighing 320 kilograms (700 pounds). It uses a more powerful explosive and a lighter titanium semi-armor piercing casing to provide the same destructive capability as the old Bullpup warhead. This gives the Block 3 TLAM-C longer range, up to 1,600 kilometers (1,000 miles).
* On 17 January 1991, the Tomahawk became the first American long-range cruise missile to be used in combat, when 52 were fired in a salvo at targets in Iraq from US warships in the Persian Gulf as part of Operation DESERT STORM, the campaign to evict Saddam Hussein from Kuwait. Other salvos followed for a total of 288 Tomahawks launched in the campaign, with excellent results. Of the first 106 Tomahawks launched, at least 100 hit their targets. The missiles were fired by eleven US Navy surface ships and one submerged submarine, the LOUISVILLE.
American and British reporters in Baghdad watched as a Tomahawk zoomed above the street before making a right angle degree turn down the next street on the way to its target. British TV camera crews filmed five Tomahawks entering the Baghdad city limits, one after another. It has been suggested that strike mission planners deliberately plotted the flight path to pass by the hotel where the reporters were staying. Among the targets hit in Baghdad were the presidential palace, the Ministry of Defense, and a central communications center. Elsewhere in Iraq, targets included chemical, biological, and nuclear warfare research facilities. As mentioned, the US Air Force also launched 35 CALCMs at targets in northern Iraq, for a total expenditure of 323 cruise missiles in the conflict.
At least one TLAM-Ds was specially modified to provide a "soft kill" on Iraqi power stations, using an improvised warhead designated "KIT-2". Its submunitions dispensers were filled with spools of conductive fibers instead of bomblets, and dumped the spools over the power stations, temporarily shorting them out.
* After their initial use in DESERT STORM, cruise missiles increasingly became a prominent weapon for the selective application of US military power:
The attacks were generally successful, but flawed by hasty planning. The first wave of attacks was believed to have generally achieved their objectives, but the second wave was regarded as ineffectual. There were reports of CALCM failures and planning glitches that targeted some of the CALCMs on hardened facilities where their fragmentation warheads would have no effect.
The strikes were in retaliation for terrorist bombing attacks on US embassies in Nairobi, Kenya, and Dar es Salaam, Tanzania, that killed more than 300 people, and were intended to disrupt plans for further attacks. The terrorist bombings were believed to have been masterminded by Saudi dissident Osama bin Laden, and the missile strikes were timed to coincide with a gathering of guerrilla leaders at the camps.
Many concerns were voiced about this strike, suggesting that the US government was engaging in a blind policy of "cruise missile diplomacy". The attack on the factory in Sudan was devastatingly effective, though the Sudanese government claimed it was a pharmaceutical plant and protested loudly over the attack. However, it appeared that the guerrilla camps were heavily dug in, and without detailed post-strike reconnaissance there were doubts that the strikes had been effective. Critics suggested that the Tomahawk strikes should have been accompanied by B-52 carpet-bombing, or that a commando raid would have inflicted more damage and obtained better intelligence. US government officials replied that the attack was proportionate, and that there was no political consensus that would have permitted heavier attacks or American casualties.
The US used Tomahawk cruise missiles to destroy Iraqi attack helicopters, and also to attack an airfield where Iraqi jet trainers were being converted to drones for spraying chemical or biological warfare agents. Missile development facilities were hit, but the US took precautions strikes against chemical and biological weapons development centers lest dangerous releases of agents occur. "Inferno" warheads that generate enough heat to destroy such agents are under development but such "agent defeat" warheads were not available at that time.
The USAF's B-52H bombers also participated in DESERT FOX, launching the big-warhead Block 1 AGM-86C CALCMs on 17 December. 90 CALCMs were launched in all, along with 330 Tomahawks, for a total of 420 cruise missiles, almost a hundred more than were expended in the Gulf War.
On the night of 24 March 1999, NATO aircraft struck at targets in Yugoslavia and Kosovo as part of Operation ALLIED FORCE, mounted in response to Serbian ethnic-cleansing efforts in Kosovo. The first wave of attacks was led by cruise missile strikes. USAF B-52Hs fired CALCMs. The Royal Navy also used their new Tomahawks in action for the first time, with the SPLENDID firing them at Yugoslav air defense systems along with Tomahawks fired by US Navy ships. A total of 100 cruise missiles were launched by USAF bombers and US Navy vessels, along with the British contribution.
The Royal Navy acquired a second batch of 20 Block 3 Tomahawks in 2001, with a third batch of 22 acquired in 2003, for a total buy of 107 Block 3 missiles. Five Royal Navy submarines were fitted to carry and launch the Tomahawks.
The Tomahawks were employed in their usual role of "spearhead" defense suppression. Although Afghan long-range air defenses were dilapidated after years of civil war in the country and many of the targets were probably not functional, the US military was not taking any chances. They made sure there was nothing left on the ground that could seriously challenge US air superiority.
The launches of CALCMs have depleted stocks. Boeing has proposed an improved new-build CALCM, but for the moment there's been no further need, and it seems likely that the Air Force regards the more modern and cheaper JASSM-ER, discussed in the next chapter, as the future. The SLCM, in contrast, seems to hanging in there handily.
* Cruise missiles have become an important part of US military capability, so much so that some critics complain that the government has acquired an instinct to use them whether it makes sense or not. One of the problems is that they are expensive and in limited supply. The US Navy still has well over 2,000 Tomahawks in their inventory, most of which have been upgraded to Block 3 standard. Of course, no nuclear armed cruise missile of any type has ever been used in action. The TASM antiship missile has also never been fired in anger, and in fact has apparently been pulled from active service and stockpiled.
The US Navy was concerned about depletion of Tomahawks after the strikes on Afghanistan and Sudan in August 1998, and later attacks put a bigger dent in the stockpile. The USN then decided to buy 1,353 new low-cost "RGM-109E Block 4" Tomahawks, better known as the "Tactical Tomahawk (TACTOM)", from Raytheon, which inherited the Tomahawk business from General Dynamics.
TACTOM costs about half as much a Block 3 Tomahawk. The major cost reduction is due to elimination of the requirement for launching the missile from a torpedo tube. Torpedo tube launch imposes unusual stresses on the missile, and the missile had to be ruggedized to survive incidental battle damage, since it was stowed near crew bunks. Attack submarines with vertical launch tubes will still be able to fire Tactical Tomahawks.
Eliminating the need for torpedo tube launch reduces the empty weight and permits greater fuel capacity. Instead of using the additional fuel capacity to obtain greater range, Raytheon decided to replace the Williams Research F107-402 turbofan with a less efficient but much cheaper small turbojet. The original engine candidate was the Teledyne J402, which is used on the Harpoon and SLAM cruise missiles, but though it was much cheaper than the F107, it couldn't meet the range requirements. Raytheon settled for the new Williams Research F415-WR-400 turbojet. The engine change slipped the program by two years.
The Tactical Tomahawk will also feature a greatly reduced parts count to lower cost and improve reliability. The total number of parts will be reduced by at least a quarter, with the number of connectors reduced by almost three quarters, and the number of circuit boards cut by more than half. The number of tailfins was even cut from four to three, giving the TACTOM a distinctive external recognition feature.
Although the Tactical Tomahawk will be cheaper, it will also have a number of enhancements:
The new features of the missile will be reflected in a new "Tactical Tomahawk Weapons Control System (TTWCS)", which will not only support the inflight reprogramming of the missiles, but also ripple-firing of up to six TACTOMs at once. The initial test flight of the TACTOM was on 23 August 2002, with initial delivery of a production weapon in the spring of 2004 and service introduction before the end of 2004.
The service then went on to acquire a TACTOM with the WDU-43/B penetrator warhead. This variant, the "TACTOM Penetrator Variant (TTPV)" or "RGM-104H", went into service in 2005. Other possible warloads include:
In addition, the Navy is considering a datalink with greater bandwidth, and an enhanced precision terrain-tracking navigation system.
* In 2004 the British Royal Navy, following up their buy of 107 Block 3 Tomahawks, placed an order for up to 105 TACTOMs. The British requested changes that would permit torpedo-tube launch of the TACTOMs. The Royal Navy is also considering carriage and launch of TACTOMs from surface vessels, though this is apparently running into competition from the Naval SCALP missile, discussed in the next chapter.
This order was followed by one in 2005 from the Royal Netherlands Navy for 30 TACTOMs. In 2006, the go-ahead was given for an order of from 60 to 100 TACTOMs for the Spanish Navy.
