* Improvements in air defense systems through the 1950s led to a parallel effort to design countermeasures. While jamming or spoofing air defense radars was one approach, there was also a more direct one: fire a missile that homed in on radar emissions to destroy the radar. A number of "anti-radar missiles (ARMs)" have been developed and deployed in the past decades. This chapter provides a short survey.
* While experiments with radar-seeking missiles were performed as far back as World War II, the first practical anti-radar missiles weren't developed until the early 1960s. One of the first was the "Martel (Missile Anti-Radar Television)". The TV-guided AJ-168 was described in an earlier chapter, while this chapter focuses on the anti-radar AS-37. Both weapons were powered by boost-sustain solid rocket motors, and had cruciform delta wings and smaller cruciform tailfins. The AS-37 was slightly shorter than the AJ-168 and had a different sustain motor.
AS-37: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 1.2 meters 3 feet 11 inches length 4 meters 13 feet 2 inches diameter 40 centimeters 15.75 inches total weight 550 kilograms 1,213 pounds warhead weight 150 kilograms 331 pounds speed Mach 0.9 range at altitude 60 kilometers 37 MI / 32 NMI _____________________ _________________ _______________________
The AS-37's radar seeker had a directional antenna. The seeker could be configured before launch to home in on specific radars, or, if operating in an environment where friendly radars weren't present, could scan through a preset band of frequencies to find a target. In either case, after launch it would home in on the target without further pilot intervention. The RAF used the AS-37 Martel on RAF Hawker-Siddeley Buccaneer strike aircraft, while the French Armee de l'Air operated it on Jaguar and Mirage strike fighters.
The original AS-37 was produced in small quantities, and is now out of service. However, an updated version of the AS-37, known as the "Armat", was introduced in 1984, and uses the same airframe but an updated radar seeker. While details on the Armat are unclear, it remains in operational service and was used by the French against the Iraqis in the Gulf War.BACK_TO_TOP
* While the British and French were working on Martel, the US Navy was developing their own, much more modest, anti-radar missile. The weapon was originally designated simply "ARM", with the designation "ASM-N-10". The Navy began development of this weapon in 1958, basing it on the airframe of the Sparrow air-to-air missile. It was put into production by a consortium of Texas Instruments and Sperry-Univac in 1963 as the "AGM-45A Shrike", after a small predatory songbird.
The Shrike was powered by a solid-fuel rocket motor. The early AGM-45A used a single-thrust motor, while the later AGM-45B, introduced in the early 1970s, used a boost-sustain motor that more than doubled the range. The Shrike had steerable, gas-actuated cruciform delta wings around its center, with cut-down fixed fins on the tail. The missile was fitted with a blast-fragmentation warhead, with a proximity fuze. The operator boresighted the Shrike on an emitter and launched after the seeker reported a lock. The missile rode down the beam to the emitter and destroyed it.
AGM-45B SHRIKE: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 0.91 meters 3 feet length 3.05 meters 10 feet diameter 20.3 centimeters 8 inches total weight 177 kilograms 390 pounds warhead weight 66 kilograms 145 pounds speed Mach 2 range at altitude 40 kilometers 25 MI / 22 NMI _____________________ _________________ _______________________
The Shrike was introduced to combat in Southeast Asia in 1966, where it was carried by US Air Force F-105G Thunderchiefs and Navy EA-6A Intruders. Initial results were poor, and led to introduction of 13 different radar seeker heads, each optimized to attack different classes of target radars. Shrikes with different seeker heads were distinguished with a numeric suffix, with designations "AGM-45A-1" through "AGM-45A-10", and "AGM-45B-1" through "AGM-45B-10".
Eventually the bugs were worked out. The Shrike became the standard anti-radiation missile for the USAF and US Navy, and was often used in defense suppression missions during the Vietnam war. The Israelis also used the Shrike, employing it in quantity during the 1973 Yom Kippur War. Unfortunately, no seeker head was available to deal with the new Soviet SA-6 antiaircraft missile system, and the Israelis suffered heavily from that weapon. The Israelis didn't find the Shrike very effective, though they went so far as to modify some of them for ground firing by adding launch boosters, and adapted Sherman tanks as launchers.
In addition, Shrikes provided by the US Navy were fitted to RAF Avro Vulcan bombers during the Falklands conflict in 1982. The AS-37 Martel had been considered for the job, since plenty of them were still available, but it was judged to not be reliable enough for a long, cold flight to the South Atlantic. The Shrike was a somewhat comical fit of a little weapon to a big aircraft, but the Vulcans made good use of the American missiles, firing a total of four missiles in two strikes that shut down Argentine radar systems on the islands. About 18,500 Shrikes of all types were manufactured up to end of production in 1982. It saw its final use in the Gulf War, being finally phased out in 1992.BACK_TO_TOP
* The Shrike lacked range and killing power. Its deficiencies quickly led the US Navy to consider a better ARM, more in the league of the AS-37 Martel. In 1966, the Navy issued a contract to General Dynamics to modify the "RIM-66 Standard" ship-to-air missile for the air-launched anti-radar mission. Development was very fast, as all it required was fitting a Shrike seeker to an existing missile, and then qualifying it. Flight tests of the big "AGM-78 Standard ARM (STARM)" began in 1967, with production following in late 1968 after operational tests in Vietnam early in that year.
STARM had cruciform strake wings, leading to big fins on the tail, and was powered by a dual-thrust solid motor. It was fitted with a blast-fragmentation warhead with contact or proximity fuzing. STARM was originally deployed over Vietnam on USAF F-105 Thunderchiefs and Navy A-6 Intruders.
AGM-78 STARM: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 1.09 meters 3 feet 7 inches length 4.57 meters 15 feet diameter 34.3 centimeters 13.5 inches total weight 635 kilograms 1,400 pounds speed Mach 2.5 range at altitude 56 kilometers 35 MI / 30 NMI _____________________ _________________ _______________________
The Shrike seeker was much too crude, and the Navy quickly moved to the "AGM-78B" variant with an improved broadband seeker. The AGM-78B's gimbaled seeker did not have to be boresighted before firing, and so the launch aircraft did not have to fly directly toward a target to attack it. The AGM-78B was also fitted with a smoke flare to mark the target, allowing other aircraft to spot and attack an air-defense site with HE and cluster bombs after the STARM blinded its radar. Further improvements were made in STARM by the Air Force through the 1970s, resulting in the "AGM-78C" and "AGM-78D" variants, featuring replacement subsystems that reduced cost and increased reliability and capability.
STARM was much more effective than Shrike, and was a favored weapon of the F-4G Phantom "Wild Weasel" variant, as well as the roughly equivalent A-6B Intruder. About 3,000 STARMs were built, with the type withdrawn from US service in 1987.
The Navy made use of STARM anti-radar seeker technology on their "RIM-66D Standard" ship-launched variant. Some numbers of STARMS were provided on to the Israelis, who named it the "Egrof Sagol (Purple Fist)" and found it very useful. They used the weapon in quantity against Syrian SAM sites in the Bekaa Valley in Lebanon during the 1982 campaign. They also fired the STARM from ground launchers, mounting three rectangular container-launchers on top of a US-built armored personnel carrier.BACK_TO_TOP
* The main problem with STARM was that it required a large launch aircraft and was complicated to operate and maintain. Something was needed that was faster and had longer range than the Shrike, but wasn't as big and complicated as the STARM, and made use of the latest seeker technology. The answer was the "AGM-88 High Speed Anti-Radar Missile (HARM)". The US Navy began studies that led to HARM in 1969, awarding a development contract for the weapon to Texas Instruments in 1974. First test flights of the HARM were in 1976, followed by low-rate initial production in 1981, with operational introduction in 1983.
The last new-build HARM was produced in 1994 after a production run of about 20,000 missiles, but those in service are being kept up-to-date through upgrades. The HARM is in service the US Navy and Air Force, as well as with the air forces of Australia, Germany, Greece, Italy, Spain, South Korea, and Turkey.
First combat use of HARM was in 1986, when US Navy Vought A-7 strike fighters used four HARMs to attack Libyan air-defense radars during a series of squabbles between the US and Libya. About 2,000 HARMs were expended on Iraqi targets during the Gulf War; they were extremely successful in keeping Saddam Hussein's air defense systems off line, and would be used against the Iraqis again. Over 1,000 HARMs were expended by Allied forces during the Kosovo air campaign in 1999. They do not seem to have been used in any quantity during the Afghanistan campaign in 2001:2002, since Afghan air defenses were in a dysfunctional state after years of civil war, but they were used during the US invasion of Iraq in 2003.
* HARM looks very much like a scaled-up Shrike, with about twice the weight of the earlier missile, though HARM can be easily distinguished from a Shrike by the squared-off tip extensions on its wings. Like the Shrike, the wings pivot while the tail fins are fixed. The HARM is fitted with a blast-fragmentation warhead, featuring both a laser-activated proximity fuze and an impact fuze. The warhead contains 20.5 kilograms (45 pounds) of explosive and 25,000 steel cubes.
The HARM is propelled by a low-smoke solid rocket motor. Speed is described as "over Mach 2", which would make HARM somewhat faster than a Shrike, but its name and other evidence suggests that's it's well speedier than that. HARM was designed to be fast enough to hit and blind air-defense sites after they had fired surface-to-air missiles (SAMs) at the launch aircraft, making the missiles go ballistic and miss. This implies it is substantially faster than most SAMs.
AGM-88 HARM: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 1.18 meters 3 feet 8 inches length 4.17 meters 13 feet 8 inches diameter 25.4 centimeters 10 inches total weight 361 kilograms 796 pounds warhead weight 65 kilograms 143 pounds speed Mach 2+ range at altitude 105 kilometers 65 MI / 57 NMI _____________________ _________________ _______________________
HARM is said to have a 360-degree engagement capability, allowing the launch aircraft to fire at targets to its rear -- though of course this imposes a range penalty, since the missile must expend fuel to turn around, and the launch aircraft's speed works against the missile.
Current HARM seekers have broadband coverage, eliminating the need for the assortment of narrowband seekers used on the Shrike. The missile's seeker is linked to radar-targeting systems on the launch aircraft that cue the weapon to attack a specific target. HARM has been deployed on a wide range of aircraft, particular the USAF F-4G Wild Weasel Phantoms, which have been retired, and Luftwaffe and Italian Tornado ECR strike aircraft. The primary HARM platform for the USAF is now the Block 50 F-16C fitted with the "ASQ-213 HARM Targeting System (HTS)", while the US Navy carries the HARM on the Grumman EA-6B Prowler, and will eventually carry it on the EF-18G Growler.
The equipment fit of the launch platform dictates to a large extent the options for using the HARM. In US Navy service, the missile can be programmed in one of three operating modes:
When carried on a USAF F-4G Wild Weasel, the HARM could be launched in a long-range "Pre-Emptive (PE)" attack on a remote target whose location had been inferred by the Weasel's electronics systems, or in a quick-reaction "Direct Attack (DA)" in response to illumination by an adversary radar.
The F-16CJ with HTS has three HARM attack modes. The "Position Known (POS)" mode is similar to the Navy PB mode but allows midcourse missile targeting updates. The "HARM As Sensor (HAS)" mode is similar to the Navy TOO mode, and the "Launch Off RWR (LOR)" mode is similar to the Navy SP mode.
* The initial AGM-88A variant was originally produced with a "Block I" seeker, which had to be factory-programmed to attack specific radars, requiring that a selection of seekers be stockpiled. The AGM-88A was updated a few years later to a "Block II" seeker, which could be reprogrammed in the field, and also had the capability to support updates through software.
First deliveries of the improved "AGM-88B" HARM took place in 1987. The AGM-88B originally used a Block II seeker, but in 1990 it was updated with "Block III" software to deal with new types of threats. At the end of the decade US Navy HARMs received a "Block IIIA" software update, providing a degree of improved counter-countermeasures capability, including a "home-on-jam" feature to attack jamming transmitters, and some ability to continue on track even when a target radar shuts down.
A third-generation HARM, the "AGM-88C", was introduced after the Gulf War. This weapon incorporated an improved seeker to cope with modern radars that operate in a variety of modes and have features such as frequency hopping. The HARM's warhead was also upgraded for better fragmentation effect, incorporating 12,845 tungsten-alloy cubes. The new warhead is said to have double the destructive effect of the old.
The initial AGM-88C had "Block IV" software, but in early 2000 the Navy began to update their AGM-88Cs to "Block V" software, providing the same benefits of the AGM-88B's Block III software, plus additional features permitted by the AGM-88C's improved hardware. No foreign users have the AGM-88C, but they can update their AGM-88Bs to Block IIIA software. New software versions continue to be developed.
* The next generation of HARM, the "AGM-88E Advanced Anti-Radiation Guided Missile (AARGM)", is now in service. Its primary feature is a "dual mode" seeker with both radar-homing and millimeter-wave imaging radar capability using a shared "conformal antenna", along with a GPS-INS navigation capability.
The AARGM seeker's radar homing element covers a wider band of frequencies and has a wider field of view than the previous HARM seeker. It also can identify an emitter autonomously after launch, so the operator does not need to have a lock before firing. If the emitter shuts down, the millimeter-wave radar will scan and identify targets, and then continue the attack. Whether the radar continues to emit or not, the millimeter-wave radar will attempt to identify the air-defense site's command van, and will attack it instead of the radar antenna. The missile's GPS-INS system can be preprogrammed to direct the missile to the target area. The missile also includes a datalink to provide guidance updates and report back for damage assessment. Thanks to its dual-mode seeker and advanced navigation capabilities, the AGM-88E can be used to attack non-emitting targets, even if they are on the move.
AARGM development was begun by the Science Applied Technology (SAT) company of San Diego, California, though the company was bought out by Alliant Techsystems in late 2002 after running into political problems. The development program was initiated in 1990, with first firing of a HARM with the new seeker in the spring of 2000 and introduction to service in 2010. The US Navy is not only obtaining new-production weapons, but also updating older HARMs to AGM-88E spec. The Italian Air Force is also involved in the program and is obtaining the new variant.
* The US Air Force has not been interested in AARGM, focusing on a less ambitious upgrade designated the "HARM Control Section Modification (HCSM)". It apparently began life in 1999 as the "International HARM Upgrade Program (IHUP)", a joint effort by the US Navy, Germany, and Italy to develop a "Precision Navigation Unit (PNU)" with a GPS-INS guidance system for the missile. By 2003, the effort had produced a prototype system, but the Navy decided focused on AARGM instead and gave up on IHUP. The USAF picked up the program, which became known as the "HARM Defense Attack Module (HDAM)" in that phase of the program.
HCSM consists of a GPS-INS guidance system upgrade with a fiber-optic gyro INS, coupled to a sophisticated guidance processor. An HCSM HARM can be programmed to restrict targeting to a predefined zone; if the missile loses emitter lock, it will continue on course, and also try to re-acquire lock if an emitter turns back on. The HCSM HARM can also be used as a "smart" munition to deal with non-emitting soft targets. Raytheon was awarded the contract for HSCM, beginning full-rate production in 2013.
* The present focus of further improvements on HARM is development of a rocket-ramjet propulsion system, consisting of a ramjet with an integral solid-fuel rocket to get it up to boost speed. The ramjet system would provide increased range and speed. BGT did work on a HARM follow-on with rocket-ramjet propulsion designated "Antiradiation Missile with Intelligent Guidance & Extended Range (ARMIGER)", but the program ran out of money and went dead. Right now rocket-ramjet propulsion for HARM is strictly in the concept and demonstration phase.
Along a different track, the Air Force had been talking with the Navy concerning a "Joint Dual-Role Air Dominance Missile (JDRADM)" or simply "Next Generation Missile (NGM)", which would be capable of operating as an air-to-air missile or anti-radar missile, allowing an aircraft to hit back at both airborne and ground threats. Such a "dual mode" weapon would also simplify logistics. The NGM exercise was wrapped up in the Air Force's need to figure out how to cram more firepower into the F-35 Joint Strike Fighter's internal weapons bays. The F-35 can only carry two AIM-120 AMRAAM missiles internally and cannot carry HARM internally at all. Such munitions can be carried externally but would then compromise the aircraft's "stealth" capabilities.
The effort was abandoned in 2012 due to funding constraints. The concept doesn't seem excessively ambitious, the main challenge being development of a seeker that could handle both air-to-air and antiradar functions, the airframe itself being seen as an AMRAAM derivative. The effort is likely to to resurface sometime in the future.BACK_TO_TOP
* In the 1980s, the US Navy decided to develop yet another ARM in order to exploit an available stock of obsolete "AIM-9C" Sidewinder AAMs. While most Sidewinder variants are infrared heatseeking weapons, the AIM-9C used semi-active radar homing, zeroing in on radar reflections of the launch aircraft's radar on a target.
The AIM-9C did not remain in service for long, but since the missile airframes were still perfectly workable, the Navy decided to adapt the weapon to the anti-radar mission. The Naval Weapons Center at China Lake, California, test-fired a proof-of concept prototype in 1981, leading to the award of a contract to Motorola in 1984 for conversion of AIM-9C stocks into operational "AGM-122A Sidearms". Of course, "Sidearm" meant "Sidewinder ARM".
The conversion involved missile airframe refurbishment; replacing the AIM-9C's original narrowband seeker with a new broadband seeker; and fitting the Sidearm's blast-fragmentation warhead with a proximity fuze then in use on more modern Sidewinder AAMs. More than 700 AGM-122As were delivered to the US Marine Corps between 1986 and 1990, primarily for use on Bell TwinCobra gunship helicopters.
AGM-122 SIDEARM: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 63 centimeters 2 feet 1 inch length 2.87 meters 9 feet 5 inches diameter 12.7 centimeters 5 inches total weight 88 kilograms 195 pounds warhead weight 11 kilograms 25 pounds speed Mach 2.3 range 16.5 kilometers 10 MI / 9 NMI _____________________ _________________ _______________________
The Sidearm is a much less potent weapon than the HARM, but it is still effective in its role of suppressing battlefield air-defense weapons. When the stock of AIM-9Cs ran out, there were considerations for producing an all-new-build "AGM-122B" with a much smarter reprogrammable seeker system, but it never happened.
Incidentally, it appears that a small number of another air-to-surface version of the Sidewinder, the "AGM-87 Focus", was built by General Electric under contract with the Navy. The Focus was based on the AIM-9B Sidewinder, with an infrared seeker that homed in on trucks and other warm targets, and was evaluated in combat in Southeast Asia in 1969 and 1970. Details are very unclear.BACK_TO_TOP
* While HARM is something of a standard ARM in Western arsenals, British Aerospace (BAE) developed a next-generation ARM that made HARM look a little stodgy in comparison. The BAE "ALARM (Air-Launched Anti-Radar Missile)" is a tubular weapon, with small cruciform nose fins and tail fins, and larger cruciform delta wings mounted toward the tailfins. It has a fragmentation warhead and is propelled by a dual-thrust solid rocket motor.
BAE ALARM: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 72 centimeters 2 feet 10 inches length 4.3 meters 14 feet 1 inches diameter 22.4 centimeters 10.6 inches total weight 268 kilograms 590 pounds speed supersonic range at altitude 45 kilometers 28 MI / 24 NMI _____________________ _________________ _______________________
ALARM was designed as a "harassment weapon". Air-defense radars can thwart a conventional ARM by shutting down until the threat has passed, but ALARM is designed to win that game. ALARM can be launched in a conventional ARM mode, climbing a bit to get a clear view, and then homing in on a target in a predefined area. If the emitter turns off, the missile homes in on the target's last known position. However, ALARM has a "loiter" mode that makes it harder to fool. On launch, the missile zooms up to an altitude from 12 to 21 kilometers (40,000 to 70,000 feet), turns off its rocket motor, and pops out a small parachute that causes it to descend nose-down. If the missile's seeker then identifies an emitter, the ALARM discards the parachute, re-ignites its rocket motor, and dives into the emitter. The length of time that an ALARM can continue its parachute descent is long enough for strike aircraft to get through the air defense gauntlet.
ALARM also has a "dual" mode, in which it has the option of direct attack or a loiter attack, depending on if there is an emitter available for direct attack. The missile is highly programmable in any case, and can be programmed to navigate to a target area and target different classes of radars in order of priority. The missile's programming can be updated by the operator up to the moment of launch.
BAE received an initial contract for the ALARM in 1983, with first firings in late 1988. The weapon was intended to be carried on RAF Tornado strike aircraft, with a single aircraft carrying up to nine ALARMs. The weapon was still in acceptance trials when the Gulf War broke out, and it was rushed into operation in RAF attacks on Iraqi air-defense systems. About 121 ALARMs were fired during the Gulf War, and the results were all that were expected, though unsurprisingly there were some defective missiles in the initial production batch. One of the peculiarities of ALARM operation was that during its climbing flight it could be mistaken for a SAM, and so launch aircraft were modified to emit a coded signal to tell other aircraft in the area that an ALARM was being launched.
The RAF continues to operate ALARM, and BAE sold a number of them to Saudi Arabia. ALARM is seen as complementary to the bigger HARM. Using the two weapons together provides more options than use of either by itself.
* In 2008, Mectron of Brazil introduced the "Mectron Anti-Radiation Missile 1 (MAR-1)" as something of a "poor man's HARM". It has cruciform midbody wings, tail fins, and nose finlets, plus a boost-sustain solid-rocket motor.
MECTRON MAR-1: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ length 4.03 meters 13 feet 2 inches diameter 23 centimeters 9.06 inches total weight 274 kilograms 604 pounds speed supersonic range at altitude 35 kilometers 22 MI / 19 NMI _____________________ _________________ _______________________
The MAR-1 is being obtained by the air forces of Brazil and Pakistan.BACK_TO_TOP
* The Soviets built a number of anti-radar missiles. One of the earliest deployed was big, long-range liquid-fuel missile with the designation "Kh-28", which was fielded in the early 1970s. A liquid propulsion scheme, using toxic storable propellants, was used because solid rockets could not meet the range requirements. The missile had delta wings and a tailplane with upper and lower vertical stabilizers. Its NATO designation was "AS-9 Kyle".
The initial Kh-28 had a seeker that could lock onto US Nike-Hercules and British Thunderbird SAM radars. The refined "Kh-28M" had a seeker that could lock onto a wider range of radars, including those of US Hawk SAM batteries, and an improved warhead. An export version, designated "Kh-28E", was supplied to several Arab countries, including Iraq, as well as Vietnam.
KH-28 / AS-9 KYLE: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 1.4 meters 4 feet 7 inches length 6 meters 20 feet 8 inches total weight 715 kilograms 1,580 pounds warhead weight 150 kilograms 330 pounds speed supersonic range at altitude 90 kilometers 56 MI / 49 NMI _____________________ _________________ _______________________
* The Kh-28 was replaced in the early 1980s by the solid-fuel "Kh-58", referred to as the "Kh-24" in early development. The Kh-58 is another big ARM, roughly in the same category as STARM, and is carried by the Sukhoi Su-24 and other large strike aircraft. However, the inspiration for the design of the Kh-58 was actually the Anglo-French Martel, though the Soviet weapon is bigger. The Kh-58 has the NATO designation of "AS-11 Kitler".
The Kh-58 has cruciform mid-body wings and tailfins, and is fitted with a seeker allowing it to lock onto a wide range of Western SAM radars. It is equipped with a secondary INS guidance system to keep it on course if it loses lock on a radar emitter.
The initial Kh-58 was followed by the improved "Kh-58U", with longer range and a refined seeker that allows lock-on after launch. A version of the Kh-58U with a simplified seeker designated the "Kh-58E" was exported to a number of Warsaw Pact countries. The Kh-58U still remains an important weapon in the arsenal of the Russian Air Force.
KH-58 / AS-11 KILTER: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 1.17 meters 3 feet 10 inches length 5 meters 16 feet 5 inches total weight 650 kilograms 1,430 pounds warhead weight 200 kilograms 440 pounds speed supersonic range at altitude 180 kilometers 110 MI / 97 NMI _____________________ _________________ _______________________ KH-58U / AS-11 KILTER: _____________________ _________________ _______________________ wingspan 1.45 meters 4 feet 9 inches length 4.8 meters 15 feet 8 inches total weight 640 kilograms 1,410 pounds warhead weight 160 kilograms 350 pounds speed supersonic range at altitude 50 kilometers 31 MI / 27 NMI _____________________ _________________ _______________________
* One of the problems with the initial Kh-28 was that it was simply too big to be carried by smaller aircraft, and even larger strike aircraft could only carry one. While the Soviet Union still felt the need for an improved large ARM, resulting in the Kh-58, a smaller ARM was also required.
In parallel with work on what would become the Kh-58, the USSR also developed an ARM variant of the Kh-23 / AS-7 Kerry ASM, designated the "Kh-27". This weapon saw limited service in the late 1970s and early 1980s, but was quickly replaced by the ARM member of the "modular" Kh-25M / AS-10 Kegler ASM.
As mentioned in an earlier chapter, the Kh-25M could be fitted with a variety of guidance systems, including a radar-seeking head. The ARM version was known as the "Kh-25MP", and its seeker could lock onto a wide range of Western radars. Apparently NATO was a bit confused by the modular system and gave this variant the entirely new codename of "AS-12 Kegler", even though any field technician could easily convert an AS-10 to an AS-12 or the reverse by swapping the seeker heads.
The Kh-25MP has been a popular weapon in Soviet-Russian service, and was exported to a number of Warsaw Pact countries. The export models had simplified seekers, almost certainly as a security measure to confound Western counter-countermeasures. The Kh-25MP is still in service in small numbers with the Russian Air Force.
KH-25MP / AS-12 KEGLER: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 73 centimeters 2 feet 5 inches length 4.35 meters 14 feet 4 inches total weight 320 kilograms 705 pounds warhead weight 90 kilograms 200 pounds speed supersonic range at altitude 25 kilometers 16 MI / 14 NMI _____________________ _________________ _______________________
* Another Soviet ARM, the "Kh-31P", is a ramjet-powered missile with a solid-fuel boost motor and a cruise speed of Mach 3.6. It was introduced into service in the early 1990s and is carried on the Su-24. The Kh-31P was designed to provide greater stand-off range than existing Soviet ARMs, with the high speed allowing it to hit adversary SAM batteries before they could counterfire against the launch aircraft. Due to the financial problems of the Russian state, the Kh-31P was only built in small numbers. The Kh-31P has the NATO designation of "AS-17 Krypton".
The Kh-31P is a long, slender missile with four ramjet intakes arranged around the back half of the fuselage, and stubby compound tailfins. It has a seeker system derived from that of the Kh-58, but with substantially greater accuracy.
KH-31P / AS-17 KRYPTON: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 1.15 meters 3 feet 10 inches length 5.23 meters 17 feet 2 inches total weight 600 kilograms 1,320 pounds warhead weight 90 kilograms 200 pounds speed Mach 3.6 range at altitude 110 kilometers 68 MI / 60 NMI _____________________ _________________ _______________________
The Russians have introduced an improved "Kh-31PM (AS-17A)", which has greater range and an improved seeker head. The original Kh-31P can be fitted with one of three seeker heads, the selection depending on the radar system to be attacked; the Kh-31PM features a single wideband seeker that can be used against all radars.
An antiship version of the Kh-31P, designated the "Kh-31A", was developed as well. It is a bit shorter, with a length of 4.7 meters (15 feet 5 inches). In an interesting irony, the Kh-31A was sold to the US Navy as an interim high-speed target, under the designation "MA-31 Target System".
The MA-31 was a Boeing "product". The Russian Zvezda organization removed the warheads and other Russian military gear and passed the missiles on to Boeing, which added control and tracking electronics. The MA-31 could be used to simulate high-altitude and sea-skimming threats. Thirteen MA-31s were delivered to the US Navy from 1995 to 2000, and in 2000 the Navy placed an order for 34 more. The MA-31 has now been replaced by the Orbital Sciences GQM-163 Coyote target, now in development. The main threats the MA-31 was meant to emulate were Russian-made supersonic antiship missiles -- which meant the Russians made money on the deal coming and going.BACK_TO_TOP
* A number of obscure ARMs were developed in the West. In the mid-1950s, the USAF apparently experimented with using the Radioplane "Crossbow" drone as a long-range air-launched ARM designated the "GAM-67", but did not put the scheme into production.
The Northrop "AGM-136A Tacit Rainbow" was even more obscure. It was basically a small air-launched cruise missile, powered by a Williams Research F121 turbofan engine, and designed to operate as a radar harassment weapon. It was a joint US Air Force / US Navy project, and tests were performed with Grumman A-6 Intruder and Boeing B-52 aircraft. A B-52 could in principle carry up to 30 Tacit Rainbows. The idea was that an AGM-136A would be launched by a strike force to fly ahead to enemy defenses and loiter overhead in the battle area, waiting for an emitter to come up. When one showed itself, the missile would dive into it and destroy the emitter with its blast-fragmentation warhead. First flight was in 1984, but the program was canceled in 1991.
AGM-136A TACIT RAINBOW: _____________________ _________________ _______________________ spec metric english _____________________ _________________ _______________________ wingspan 1.58 meters 5 feet 2 inches length 2.54 meters 8 feet 4 inches total weight 195 kilograms 430 pounds warhead weight 12.2 kilograms 40 pounds speed subsonic endurance 1.5 hours _____________________ _________________ _______________________
Tacit Rainbow was supposed to be a low-cost weapon, but its final estimated unit price was something like $200,000 USD. This high price and the long development cycle suggest that the program was not well-managed.BACK_TO_TOP