The U.S. Harpoon missile has many variants. To begin with, the prefix is AGM/RGM/UGM-84 Harpoon depending if the missile is, respectively, air-launched, ship-launched or submarine-launched. Originally, the Harpoon was a dedicated anti-shipping missile, but now has a land attack variant, AGM-84 SLAM, which itself has variants.
While the Harpoon retains a distinct air and submarine launch role, it has been deemphasized on U.S. surface ships. The newer Flight IIA Burke-class destroyers do not retain Harpoon launchers, with the space given to helicopter support. SM-2 series missiles, from an older ship (USS Wainwright) not using the current vertical launch system version were used successfully against Iranian surface targets in 1988, during Operation PRAYING MANTIS, and the helicopters on the Burkes and Ticonderoga-class cruisers can deliver AGM-119 Penguin anti-shipping missiles. With these two systems, the U.S. Navy apparently believes that the Harpoon does not give significant additional anti-surface warfare (ASuW) capability to the ships. The ability of the cruisers' and destoyers' helicopters to provide beyond-the-horizon radar guidance reduces some of the need for the Harpoon's capability to guide autonomously. That the Harpoon is subsonic also decreases its ability to attack a ship with good point defense. Nevertheless, it is still in widespread use with allied navies, and on U.S. aircraft and submarines.
The basic Harpoon can be fired in one of two modes: a three-axis stabilized mode that effectively is an inertial guidance system, or bearing only mode. In the first mode, a three-axis stabilized Attitude Reference Assembly (ATA) in an AN/DSQ-44 guidance section, sends the missile to the general area of the target. At a programmable time, the Harpoon will activate a AN/DSQ-28 J-band radar for terminal homing.
Using ATA, the Block 1C (introduced in 1985) and later versions need not take a straight-line course to the target, but can fly "zig-zag" or "dog-leg" paths. These alternative courses have two potential advantages:
- Multiple Harpoons can be launched on different approach courses, so they converge simultaneously on the target, but from different directions, potentially overloading defenses.
- The bearing on which the missile is first detected does not necessarily point back to the launching platform.
In BOL, however, the radar is activated at launch, so the location of the target need not be as precisely known as with ATA.
Again as programmed, the Harpoon can either stay sea-skimming to hit its target near the waterline, or do a "pop-up" maneuver to dive into the target for maximum penetration.
Range has steadily increased in each Block of modifications. Block 1D has a longer airframe that will not fit in a submarine torpedo tube, so only air and surface launched versions were planned. The greater range also allowed a "reattack" capability, where if the terminal seeker does not find the target, it can enter an orbiting pattern while it tries to find the target. While Block 1D was cancelled, Block 1G, made from Block 1C missiles, had reattack and better electronic protection.
A Block 1G, with GPS guidance, was not bought by the U.S. Navy, but a Block 1J variant was approved for export, and a ship-launched version has been sold to countries including Egypt, Taiwan and the United Arab Emirates. South Korea bought both air- and ship-launched versions.
The air-launched AGM-84 operates from a wide range of Navy aircraft, but also can be launched by Air Force B-52 bombers. Along with the ability to lay air-dropped naval mines, the B-52 can supplement naval anti-surface warfare; it fires the AGM-84L model.
Harpoon-firing ships have the AN/SWG-1 Harpoon Fire Control System.
- Engine: One Teledyne /CAE J402-CA-400 turbojet; 680 lbs thrust
- Wingspan: 3 ft 0 in
- Length: 12 ft 7 in
- Diameter: 1 ft 1 1/2 in
- Weight: 1,145 lbs
- Speed: 855 km/h
- Range: 60+ nautical miles
- Armament: 488 lbs high-explosive
- Cost: $474,609
- Parsch, Andreas, Boeing (McDonnell Douglas) AGM/RGM/UGM-84 Harpoon, DesignationSystems.net