Type
Short-range, laser-guided, air-to-surface missile.

Development
The AGM-114 Hellfire (an acronym for Heliborne, Laser, Fire and Forget) Modular Missile System was designed in the 1970s as a multimission anti-armour and precision attack weapon that would be effective against tanks, bunkers and structures. The requirement included the attack of both stationary and moving vehicle targets. Studies relating to the Hellfire began around 1970 and exploratory development began in 1971. Advanced development of the missile continued through 1976 when the US Army awarded an engineering contract to Rockwell International (now Boeing Corp). Initially the Hellfire missile was to use a tri-service laser seeker. However, Martin Marietta (now Lockheed Martin) is said to have approached the army with a low-cost seeker that it had developed privately. The army initiated a seeker competition between Rockwell and Martin Marietta, which was won by the latter.

The first guided launch of a AGM-114A Hellfire missile took place from a AH-1G Cobra helicopter in late 1978 and in 1979, several ballistic and guided firings took place from AH-64 Apache helicopters. Operational testing by the US Army was completed in 1980 and in 1981, Hellfire was declared ready for production. The first operational rounds were delivered in late 1984 and the Hellfire missile system entered service in 1985. An AGM-114B version was developed for the US Marine Corps, with a low-smoke motor and a safety arming device for shipboard operations. At the same time other seeker options were looked at; dual-mode RF/IR system, Imaging Infra-Red (IIR) and MilliMetre-Wave radar (MMW). It is believed that a RF/IR system was developed and tested, but there have been no recorded deliveries of such a seeker and the current status of the programme is unclear. The IIR and MMW seekers were funded as part of a US Army fire-and-forget Hellfire programme, but this programme was shelved and only the active radar appears to have progressed beyond the early stages of development. The next missile in the family, AGM-114C, was a US Army version of the AGM-114B without the safety arming device.

Soon after the missile was introduced into service, it attracted the attention of the Swedish Coast Artillery Forces, which were seeking a short-range, anti-ship missile specifically for use against landing craft and smaller warships. In 1984, Swedish Defence Materiel Administration placed a contract to adapt Hellfire for the coastal defence anti-ship role. A production contract was placed in 1987 and the system entered service in Sweden as RBS-17. The anti-ship missile with its special to type blast/fragmentation, delayed action warhead is also used in the air-to-surface role.

In 1991, the production of a new variant, AGM-114F, (sometimes referred to as Interim Hellfire) was authorised. The major improvement incorporated was a precursor warhead to give the missile the ability to defeat reactive armour. As a result of an identified shortcoming of the Hellfire system during the 1991 Gulf War and in order to introduce other improvements, a further development programme was started in 1991. In the early days, the programme was known as the Hellfire Optimised Missile Systems (HOMS), but has since been designated AGM-114K and renamed Hellfire 2. AGM-114K incorporates improvements over the AGM-114F including solving the laser obscurant/backscatter problem. Other improvements incorporated are; improved target re-acquisition capability, a digital autopilot to increase launch speeds from 300 knots to M1.1 and produce a steeper terminal dive onto armoured targets, a more powerful precursor warhead, reprogrammability to adapt to changing threats and mission requirements, improved electro-optical countermeasures and regaining the original Hellfire missile length and weight. After successful firing tests, the initial production contract for AGM-114K was awarded in 1993 and deliveries started in December 1994. A second Hellfire 2 (AGM-114K) was developed from 1994, with a blast fragmentation warhead for use against ship targets.

In 1992, the US Army selected a millimetric-wave seeker version of the Hellfire 2 missile for its Longbow helicopter programme and this has the designator AGM-114L. The requirement was to give the Hellfire missile system an all-weather and day/night capability. The Longbow system, formerly known as the Airborne Adverse Weather Weapon System (AAWWS), is being developed for integration onto 220 of the US Army AH-64D Apache helicopters and is planned for one-third of the future RAH-66 Comanche fleet. The programme includes development of a Fire-Control Radar (FCR) system and numerous modifications to the helicopter. The first launch of a Hellfire missile from a Longbow-equipped AH-64D Apache helicopter took place in June 1994. Successful firings have also taken place from an Apache helicopter using data passed from a Longbow-equipped Apache flying more than 700 m apart, without the launch aircraft having acquired the target. GEC-Marconi Dynamics UK (now Marconi Electronic Systems), proposed an active millimetric-wave (94 GHz) seeker as a further alternative and this system, known as Brimstone, was selected by the UK MoD in 1996 for anti-armour weapons from both helicopter and fixed-wing aircraft. The Brimstone missile uses AGM-114K missile airframe, warhead and motor assemblies.

A night firing sight system, AN/UAS-12C, has been developed for use on helicopters with both BGM-71 TOW and Hellfire missiles; this system has a laser range-finder and designator, a FLIR with x30 magnification and a telescope for day viewing. In 1994, a new Hellfire two- or four-rail launcher, designated M299, was introduced. It has a MIL-STD-1760 aircraft interface, standard NATO 356 mm spaced suspension lugs and covers all Hellfire types, as well as eliminating three Line Replacement Units (LRUs).

Hellfire missiles have been cleared for carriage on AH-64 Apache, AH-1W SuperCobra, MD-530 Defender, OH-58D Kiowa, SH-60/HH-60 Seahawk and UH-60A Black Hawk helicopters. In addition, integration trials have been made with the A 129 Mangusta, BO 105, Lynx and S-70 Seahawk helicopters. Other air-launched applications considered include; RAH-66 Comanche, SA 342 Gazelle, AS 532 Cougar and UH-1 helicopters and A-10, AV-8B Harrier, AC-130 Hercules, F-4 Phantom, F-5E Tiger II, F-16 Fighting Falcon, F/A-18 Hornet, Harrier and OV-10D Bronco aircraft.

As well as the coast-to-ship mode, design studies have been completed for possible air-to-air, fixed-wing, air-to-surface, vehicle-mounted, surface-to-surface, surface-to-air and ship-launched variants. Initial ship firings were carried out in 1989 and trial firings were made in 1990 against aircraft targets, to prove Hellfire in the air-to-air role. A surface-to-air trial was completed in 1992 against drone helicopter targets. Future growth proposals are reported to include an extended range pulsed rocket motor, boundary layer thrust vector control, and insensitive munitions. In 1998, it was reported that a joint programme between DARPA, US Army, US Marine Corps and US Navy would examine the possible use of Hellfire 2 missiles for a Rapid Reaction Force, using both ground and vehicle launched missiles.

A technology insertion programme for Hellfire improvements will run from 1998 to 2002. This may include a dual mode seeker, possibly semi-active laser and imaging IR and lower cost components to replace life-expired warhead and motor assemblies. A proposed Hellfire 3, with a range increased to 12 km, is being considered by the US Army, with a planned in-service date around 2007. This missile will probably be a joint BGM-71/AGM-114 replacement, designed to fit both launcher and weapon control systems. In 1998, a proposal was made for a demonstration, fitting AGM-114 Hellfire missiles to an Amber UAV, so that an Unmanned Combat Air Vehicle (UCAV) mission capability can be evaluated.

Description

The Hellfire family of missiles consists of four generations; basic (AGM-114A/B/C) and anti-ship; interim (AGM-114F); Hellfire 2 (AGM-114K); Longbow (AGM-114L). All Hellfire missiles are similar in shape in that they have a cylindrical body with a dome shaped nose section that has four small clipped delta stabilising fins in a cruciform configuration. On the rear third of the missile around the motor section are four in-line, wide-chord, short-span fixed wings with control fins at their trailing-edges. The missiles are of modular construction being made up of five major sections; seeker, warhead, guidance, propulsion and control. Depending on missile type, the seeker can be semi-active laser or active MMW radar and depending on mission requirement the warhead can be single or tandem HEAT, or blast/fragmentation. For an air-to-air application, the single anti-armour unit would be used with a proximity fuze rather than impact. The guidance units for the AGM-114 A/B/C/F and RBS-17 anti-ship missile are identical, containing actuation gas storage, thermal battery, autopilot electronics and guidance section with pitch and yaw/roll gyros, whereas the AGM-114K and AGM-114L missiles have a totally redesigned unit (see below). All current Hellfire missiles use the same minimum smoke, internal burning, solid propellant motor which accelerates the missile to greater than M1.0. The control unit containing the actuators for the control fins forms the boat tail around the motor's exhaust.

AGM-114A is 1.63 m long, has a body diameter of 178 mm, a wing span of 0.33 m and a launch weight of 45.7 kg. It is fitted with a single shaped charge 8 kg warhead that is detonated by an impact fuze. Guidance is by a semi-active laser seeker tracking a coded laser beam reflected from a designated target using a 1.06 µm wavelength. The missile can also be launched from low level before lock on and will then search for the reflected beam and lock onto target. With different designator codes it is possible to ripple fire the missiles against different targets. This missile has a minimum range of 1.5 km and a maximum range of 8 km. The ground-launched RBS-17 anti-ship missile is the same size and operates in the same manner as the AGM-114A. However, because of the slightly heavier blast/fragmentation warhead and the delayed fuzing system, the missile's launch weight is 48.3 kg. AGM 114B and C are identical in size, weight and operation to the AGM-114A. AGM-114B was developed for the US Marine Corps, with a low-smoke motor and a safety arming device for shipboard operation. AGM-114C was similar to AGM-114B, but without the safety arming device.

The AGM-114F is basically an AGM-114B/C missile with a forward warhead module inserted between the existing SAL seeker section and main warhead. This additional module contains a small precursor explosive charge and a detonation delay spool. This modification has increased the missile's length to 1.8 m and launch weight to 48.6 kg. This version has a minimum range of 1.5 km and a maximum range of 8 km.

The AGM-114K Hellfire 2 is a totally redesigned missile and although it is identical in appearance to the basic AGM-114A, most of the internal components apart from the main warhead, and propulsion and control units have been changed. The new glass-domed section contains an improved semi-active laser seeker, digital autopilot and guidance electronics, precursor warhead with initiating charge, attitude gyros and power supply. The original guidance section has been replaced with a new unit called the control interface group and contains an electronic safe and arm unit, thermal battery and toroidal pneumatic accumulator. AGM-114K is 1.63 m long, has a body diameter of 178 mm, a wing span of 0.33 m and a launch weight of 45.7 kg. It is fitted with an improved tandem warhead in order to defeat explosive reactive armour. The larger 100 mm precursor charge has a molybdenum liner, which is initiated by a different primary charge to cater for the new Magnavox electronic safety and arming unit. The updated SAL seeker has been hardened against electro-optical countermeasures (EOCM) and has improved target discrimination tracking the target rather than backscatter from dust and water vapour. The digital autopilot, based on an Intel microprocessor, provides more accurate control during short-range engagements, and permits trajectory shaping allowing Hellfire 2 to fly beneath cloud cover so that its seeker does not lose target lock on. It also ensures that the terminal phase, dive trajectory remains constant at the optimum angle, regardless of range. It is reported that Hellfire 2 can engage targets between 0.5 and 9 km. The second AGM-114K Hellfire 2 missile version has a 12.5 kg HE blast/fragmentation warhead for use against ship targets and this increases the missile weight to 47.9 kg.

Hellfire missiles can be carried on two or four rail launcher assemblies, the original launcher was the M272 and the latest version is the M299. The M299 incorporates MIL-STD-1760 interfaces; the two rail version weighs 43.6 kg empty and 141 kg loaded, the four rail version weighs 66 kg empty and 260 kg loaded. The M299 can carry AGM-114A to -114K versions and Longbow Hellfire 2.

Longbow is an integrated Fire-Control Radar (FCR) and missile system consisting of a millimetre-wave radar fire-control system mounted on the main rotor mast of the AH-64D Apache/Longbow helicopter and a Hellfire missile incorporating an new MMW active radar seeker. The AGM-114L Longbow missile is basically a AGM-114K Hellfire 2 with the SAL seeker replaced by a MMW one and has a dome-shaped radome instead of a glass-domed nose. The tandem warhead group, control interface group, propulsion and control sections remain the same. The missile, which is sometimes referred to as Longbow/Hellfire 2 is 1.78 m long, has a body diameter of 178 mm, a wing span of 0.33 m and is expected to weigh just under 50 kg. During an attack, target acquisition is carried out either by the Longbow Apache's AN/APG-78 FCR or Target Acquisition Designation Sight (TADS). Its parameters are fed to the Hellfire missile in order to align the missile active MMW radar and inertial guidance systems. The FCR contains an integrated RF interferometer, which locates and classifies any emitter targets and then cues the FCR to the emitter. If it is a moving target or a short-range stationary one, the missile radar acquires the target and Locks On Before Launch (LOBL). In this mode, once launched, the missile's radar updates the missile's guidance system up to target impact. If the target is a long-range stationary one, the missile is launched in the Lock On After Launch (LOAL) mode. In this mode, the missile's inertial guidance steers it in the direction of the target. Once the missile's scanning radar beam acquires the target, the missile locks on and the radar updates the guidance system up to target impact. The Longbow Hellfire 2 missile is expected to have the same range capability as AGM-114F, with a minimum range of 500 m and maximum range of 9 km.

Operational Status
AGM-114 Hellfire missiles entered service in 1985 and are in operational use with the US Army and US Marine Corps. Production is expected to continue until 2001 and an estimated total of 65,000 missiles will be built. A development contract was awarded in March 1990 for AGM-114K Hellfire 2, with a US Army production order of 8,578 missiles planned and first deliveries in 1997. By 1999, over 16,500 Hellfire 2 missiles had been ordered by the US and for export, with over 10,000 deliveries completed. Around 110 Hellfire 2 missiles have been tested, with 107 reported as successful. The US Army ordered 100 AGM-114K anti-ship version missiles in 1998. The first trial firing of an active MMW radar-guided AGM-114L Longbow Hellfire 2 missile was carried out in early 1994, this version was developed for the AH-64D Longbow Apache helicopter. Low rate initial production was authorised in December 1995 and the Longbow Hellfire 2 entered service in 1998. The US Army plans to purchase 12,905 AGM-114L missiles.

An export order to Sweden was announced in 1987 for a coastal defence variant, known in Sweden as RBS-17 and Norway placed an order for similar missiles in 1994. Export orders for air-launched Hellfire missiles have been reported to Canada, Egypt, Greece, Israel, South Korea, Kuwait, Netherlands, Saudi Arabia, Singapore, Taiwan, Turkey and UAE. Turkey ordered AGM-114K anti-ship missiles in 1999, the first export order for this version. The UK ordered Brimstone (Hellfire with a UK MMW active radar seeker), and for US-built Hellfire 2 and Longbow Hellfire 2 missiles in 1996.

Hellfire production in the USA has been dual-sourced between Rockwell International (now Boeing Corp) and Martin Marietta (now Lockheed Martin), but in 1995, the companies announced that they would combine the Hellfire 1 and Hellfire 2 programmes with a single assembly, excluding the Longbow variant, under a new company Hellfire Systems LLC. AGM-114L (Longbow Hellfire 2) missiles are being built by the Longbow Limited Liability Co (LBL), a joint venture between Lockheed Martin and Northrop Grumman. Hellfire missiles are reported to have been widely used against Iraq in the 1991 Gulf War, with about 4,000 fired. An unconfirmed report in April 1999 stated that Hellfire missiles had been fired from AC-130U Hercules `Spectre' gunships against targets in Serbia and Kosovo.

Specifications

Contractors
Boeing Corp

Northrop Grumman

Four AGM-114 Hellfire missiles on the outer wing pylon of an AH-64 Apache helicopter (US Army) (1999)

Three sectioned AGM-114 missiles; the anti-ship missile with an HE blast/fragmentation warhead (top), Hellfire 2 anti-armour missile with two tandem warheads (centre) and Longbow Hellfire 2 (bottom) (Duncan Lennox) (1999)

Sixteen AGM-114 Hellfire missiles being carried by a UH-60A Black Hawk helicopter (1990)

An AH-64D Longbow Apache helicopter carrying AGM-114 Hellfire missiles. The mast-mounted fire-control radar is above the rotor head, with the electro-optical sight system at the nose (Northrop Grumman) (1998)

AGM-114 Hellfire (1995)

A diagram of the M299 Hellfire launch assembly (Boeing) (1998)

An AGM-114K missile (US Army) (1999)