Harpoon, developed and constructed by Boeing is a fully autonomous all-weather anti-ship missile. First flown in 1972 around 6800 units of the aptly named Harpoon are in-service with around 25 nations.

Boeing Harpoon © Boeing Inc.

Originally Harpoon (AGM-84) was designed as a ship launched weapon for the United States Navy, the Harpoon can now also be launched from aircraft, submarines and land systems. Like similar systems such as Sea Eagle the weapon is designed as a high subsonic surface skimming device. If launched from ship or shore based installations the weapon is initially propelled from a standard ASROC/TARTAR launch tube via a small solid booster with a ~3s duration burn time. Upon reaching critical velocity the booster detaches allowing the turbojet engine to take over. For subsurface launches the missile is contained within a launch capsule enabling firing to be achieved via standard torpedo tubes. Upon leaving the submarine small fins deploy and the unit is orientated to the surface. Once there the capsule ends detach and the booster fires as with a standard ship based launch. For air launches the operation is simplified since the aircraft's velocity removes the need for additional rocket boosters.

The current Block-1 series missile comprises of essentially 5 components; guidance, warhead, sustainer, boat-tail assembly and control fins. The warhead, weighing some 222kg (489lbs) is a high explosive based unit capable of surviving the initial hull impact. This in turn enables detonation inside the ship increasing the destructive effectiveness.

The flight control section comprises three parts; mid-line fins, boat-tail assembly and the guidance fins. The mid-line fins, connected to the sustainer section are present purely to provide lift. For control there are four aluminium fins at the rear of the missile. These are powered by four actuators within the boat-tail assembly. Harpoon is propelled by an integral Teledyne CAE-J402 turbojet motor utilising JP-10 fuel all contained within the sustainer section. This also houses the on-board batteries and mission electronics.

To provide a fully autonomous capability the Harpoon is equipped with an active radar for terminal acquisition combined with a radar altimeter and a digital mid-course correction system. In the late 1970's the British Royal Navy requested modifications to the basic guidance system. This yielded the Block-1B system offering a reduced cruise altitude. As a follow-on the USN produced an improved variant, Block-1C. In 1989 the USN requested a further upgrade to be made introducing the ability to undertake multiple re-attack patterns. However the fall of the Soviet Union put paid to funding of this venture. Instead Boeing are now offering the upgrade, designated as Block-1G to current customers.

The latest upgrade project, to be designated Block-2 will see Harpoon gain the JDAM GPS/INS guidance unit. In addition the possibility of incorporating a thrust vectoring system have been examined but no plans currently exist to incorporate such a feature. In addition to the radar guided variant there is an additional model utilising an Imaging Infra Red seeker, named SLAM. At the present time an upgraded version of this missile, SLAM-ER is entering production.

Harpoon has proved to be both exceptionally reliable (with a flight reliability factor of nearly 95%) and extremely effective. In all launches carried out thus far (including the Gulf War and other Gulf confrontations) the missile has achieved a 100% kill rate.

Please note that the data given below applies to the air launched variant.

* : Note that all ranges quoted are based on mean figures from various data sources. Actual achievable range will depend on a great number of factors and may be no where near those quoted.