In 1967, following the sinking of the Israeli destroyer Eilat by an SS-N-2 'Styx', the US Navy began to show serious interest in developing its own anti-ship missile. The result was a formal proposal that led to the McDonnell Douylae Harpoon, but an interim altemative was also sought. This became the Fireflash SSM, based on the BQM-34A Firebee target and reconnaissance drone. By late 19'11, however, the Fireflash was dropped as it was rapidly becoming a serious competitor to Harpoon rather than just an interim weapon. In the meantime Harpoon had begun life in the Fiscal Year 1968 programme as a 92.5-km (57.5mile) range anti-ship missile (designated ACM-84A) suitable for air launch. By 1970 Harpoon's capabilities had been extended to ship-launch applications (as the RGM-84A), and in January 1971 McDonnell Douglas was selected as the prime contractor. The final variant, the encapsulated torpedo tube-launched Sub-Harpoon version for submerged launch from submarines, was started in 1972 and subsequently replaced the Submarine Tactical Missiles (STAM) programme that was cancelled in the following year.

The Harpoon development programme always emphasized simplicity and low technical risk. The missile, boosted by a solid-propellant rocket and sustained by a Teledyne CAE J402 turbojet, is usually fired in a pre-set Range and Bearing Launch (RBL) mode, turning on its Texas Instruments two-axis active-radar terminal only at the last moment to acquire the target without giving it time to instigate evasive measures. The frequency-agile

radar can be set for large, medium or small acquisition windows that determine the range from the target at which the radar is activated. The smaller the window the more precise the initial target data must be, and the less the chance that the missile will be defeated by defensive ECM techniques in its terminal flight phase. Initial guidance in the flight is undertaken either by Lear Siegler or a Northrop three axis strap down altitude reference system with a Honeywell radar altimeter, working through cruciform rear fins. The alternative launch technique is the Bearing Only Launch (BOL) mode, in which the missile is fired on the target bearing and the radar is activated early in the flight, scanning 45° to each side of the missile's bearing to search for a target. If no target is acquired after a suitable time on the initial bearing, the missile switches to a pre-set search pattern. In either launch mode, once the target is detected and the seeker achieves a lock-on, the missile climbs rapidly in a pop-up manoeuvre and dives onto it. The newer Block 1B and Block IC missiles now being built

have a range increase of 15 per cent and a sea-skimming terminal attack profile. The latter was 5rst adopted for the Royal Navy's Sub-Harpoon missiles. A Block II missile with a greater than 190-km (118-mile) range, variable flight profiles and improved ECM resistance is expected in the late 1980s for service in the 1990s.

It is reckoned that one Harpoon will destroy an 'Osa', 'Komar', 'Matka' or 'Nanuchka' class missile boat; two will disable a frigate; four will knock out a missile cruiser; and five will destroy a 'Kirov' class nuclear-powered battlecruiser or a 'Kiev' class carrier. The warhead is a 227-kg (500-Ib) penetration-blast type fitted with time-delay contact and proximity fuses. On surface warships the Harpoon is either carried in its own cylindrical container-launcher or carried in the missile magazine of a Tartar/Standard SM-1 launcher. On some frigates two of the boxes in the ASROC ASW missile launcher have been converted to fire the Harpoon. Aircraft normally carry two missiles under their wings. A new vertical-launch system for ships, cap

able of firing the Harpoon among other missiles, is currently under development for newer generations of USN vessels.

The Harpoon series is in widespread service with the USA and its allies, operators of the shipborne version including Australia, Denmark, Greece, Iran, Israel, Japan, the Netherlands, Saudi Arabia and Turkey. The USA deploys all three versions, and other operators of the air-launched model are Japan and the UK, while Sub-Harpoon is additionally found in the inventories of Australia and the UK.

Specification McDonnell Douglas Harpoon

 Dimensions: length 4.58 m ( 15 ft 0.75 in) for RGM-84A and SubHarpoon, and 3.84 m ( 12 ft 7 in) for AGM-84A; diameter 34.3 cm ( 1 ft 1. S in); span 91.4 cm (3 ft 0 in)

 Weights: total round 667 kg ( 1,470 lb) for RGM-84A and Sub-Harpoon, and 522 kg ( 1,150 lb) for AGM-84A; warhead 227 kg (500 lb) Performance: maximum speed Mach 0.85; range 120 km (75 miles)