Initially, the development of the Harpoon missile began as an aircraft-launched missile exclusively, but one event changed all the plans at once. On October 21, 1967, in the midst of the Suez Crisis, the Israeli destroyer Eilat was sunk by three Soviet anti-ship missiles P-15 Termit (SS-N-2 Styx, NATO codename) launched by several Egyptian Komar-class missile boats from inside the harbour of Port Said. This event seriously worried the US Navy, which until then had not considered this type of missile a serious threat. In 1970 the design guidelines for the new missile were changed, giving priority to launching it from naval platforms alongside aerial.In June 1971 McDonnell Douglas Astronautics (MDAC) was chosen as prime contractor, and in July 1973 the development contract was signed. 40 test missiles were manufactured under Harpoon designation, 34 of which were launched between 1974 and 1975. From all the prototypes built, 15 were of the RGM-84 variant for launch from surface ships, and some were launched in tests from the USS High Point (PCH-1) hydrofoil patrol craft sailing on their planes (on the image). In addition, three Harpoons were launched from submarines and the remaining 16 from aircraft.The test results were excellent, with no failures or serious anomalies detected. However, at the end of 1975, random failures in the tests began to appear and forced the start of production to be delayed. Finally the first Harpoon missiles left the factory in 1976, the year in which the first 315 missiles were manufactured. The name Harpoon was assigned at the beginning of the program in relation to the missile’s mission, which was to hunt submarines, called “whales” in naval circles.Harpoon missile is made up of the seeker head, followed by the warhead, the propulsion section and finally, the control section. The search head is composed of the flat radar antenna with mechanical scanning followed by the active radar seeker, then there is a short pulse radio altimeter and finally the inertial guidance unit for cruise flight. The warhead is composed by the explosive charge, a contact delay fuse and a pressure-sensitive electrochemical arming and safety mechanism. The propulsion section is occupied by the single discharge silver-zinc main battery, followed by the semi-faded fixed air intake for the turbojet, the JP fuel tank, a pyrotechnic ignition-starter mechanism and the turbojet engine. At the end of the missile are the electromechanical control actuators that govern the four cruciform tail fins. In the case of naval Harpoons, a detachable solid rocket booster was added to the control section.The AGM-84 missile is a long-range subsonic missile equipped with a warhead containing 227 kg of high explosive that detonates by means of a delayed contact fuze. In this way, the missile penetrates the target’s hull before exploding, causing increased damage. Target data can be entered prior to launch into its Lear-Siegler inertial guidance system, capable of controlling the missile even at 90º from the launch direction. After its launch, the missile flies flush with the water surface (sea skimming) at a height and cruising speed thanks to a radio altimeter. Near the target, the Texas Instruments PR-53/DSQ-58 active homing radar searches and lock the target and finally orders a sudden ascent to hit the target from above.The missile is powered by a 300 kg thrust Teledyne CAE J402 CA-400 turbojet that allows it a cruise speed of about 600 km/h and a terminal speed of Mach 0.75 (918 km/h). The RGM-84 and UGM-84 naval variants also feature an Aerojet MX (TBD) B446-2 solid-fuel rocket booster that provides the power needed for launch until the main turbojet is activated. The AGM-84 aerial launched variant is 74 cm shorter and about 140 kg lighter because it lacks the solid rocket booster. The range of the missile depends on the model but it is between 93 km for AGM-84A, 110 km for AGM-84E SLAM, 113 km for UGM-84, 130 km for AGM/RGM/UGM-84L, 270 km for AGM- 84H/K SLAM-ER and 278 km for RGM/AGM-84F variant. A new variant designated as Harpoon Block II+ ER is currently under development with a range of 310 km but with a smaller warhead of only 140 kg.The Harpoon is one of the most successful anti-ship missiles in the world thanks to its performance and its moderate price of around 1.5 million dollars a piece. These antiship missiles are in service with about 50 users among Navies and Air Forces around the world. Around 8,000 missiles of all variants has been built since 1977, these being the following: AGM-84 (air launch), RGM-84 (launch from surface ships), UGM-84 also called Sub-Harpoon (for submarine launch), AGM-84E SLAM (air-launched land attack cruise missile) and AGM-84H/K SLAM-ER (air-launched land attack cruise missile) which has replaced the previous one.The Harpoon is a weapon easily adaptable to many of the fighter-bombers and maritime patrol aircraft in service, as well as being installable on practically any combat ship. Among the aircraft that use or have used the Harpoon we find the A-6 Intruder, A-7 Corsair II, AV-8B Harrier II, F-16A/B Fighting Falcon, F/A-18 Hornet, F/A-18F Super Hornet, SEPECAT Jaguar, F-111C, B-52H, S-3 Viking, P-3C Orion, P-8 Poseidon, P-8I Neptune and Fokker 50 (MPA). Regarding naval units, the list would be endless, but in summary it can be said that any ship with a displacement greater than 200 tons can be the recipient of this missile.
