Air Weapons: Old Missiles Never Die

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June 28, 2018: The U.S. Navy is converting 271 older AGM-88B HARMs (High-speed Anti-Radiation Missile) to the more capable 88E model for $680,000 each. A new 88E costs $1.26 million each. For over half a century most guided missiles were built with these upgrades and refurbishment in mind. The older missiles not only have more advanced components installed but the entire missile is examined and any component needing replacement gets that done. Older spare parts for the 88B are also replaced, as needed, with those that work in the 88E. Most AGM-88s are being used on U.S. made EA-18G electronic warfare (EW) aircraft, which now takes care of certain EW missions, like SEAD (suppression of enemy air defenses) for the air force and marines as well. To do that they need the latest model HARM.

The AGM-88 comes in various models, giving users lots of options. Some users only need the older 88B but most want the latest model. The AGM-88B HARM entered service in 1983 and used a passive radar seeker which homed on enemy fire-control radars emissions in order to destroy the radar and thus render Surface-to-air missile (SAM) systems useless (well at least those which use radars for target tracking). In 1999 (the Kosovo War against Serbia) the 88B HARM was found to be vulnerable. The Serbian forces limited their radar usage to a minimum and used quick radar shutdown techniques and “pack and leave” tactic for their SAM units. Because of these tactics, HARM had problems acquiring targets. That’s because the missile has precision guidance only when enemy radar is working all the time. Otherwise the 88B reverts to “offline mode” (using less accurate INS/GPS only). As a result,

NATO forces failed to silence most Serbian SAMs during the campaign. There were calls for upgrades to the 88B and some software upgrades seemed to deal with the problems encountered against Serbia. But the potential threats kept appearing and AGM-88 upgrades continued and that resulted in some major changes and a new model HARM.

The first 88E production models were delivered in 2010. This included testing for use on the EA-18G, which entered service in 2011. AGM-88E testing ran into many problems in the three years before it entered service and there were more hardware failures than expected. The manufacturer admits that it is still working on some of these issues but that, in its current state, the AGM-88E is good to go.

Not only is the E model an improved version of the 88B it also includes major modifications that enable it to hit moving ships. This makes the AGM-88E an effective anti-ship weapon as well. Meanwhile, another upgrade of the AGM-88 has entered service. The AGM-88F is very similar to the 88E but from a different manufacturer and aimed at export sales. The 88F completed testing in 2014 and entered production. This version will also have the anti-ship capability.

All these upgrades seen in the 88E and 88F contributed to the missile getting a new name. It’s now an AARGM (Advanced Anti-Radiation Guided Missile) instead of a HARM. The older AGM-88s can easily be upgraded by simply replacing older sensors and guidance system components with new ones to create an 88E or 88F. AARGM weighs 361 kg (794 pounds) and can detect and attack targets more than 150 kilometers away while traveling at a speed of 2,450 kilometers per hour. The AGM-88E can transmit a picture of the target, just before it is hit, so the user can be certain of what was taken out. The AARGM was developed jointly by U.S. and Italian firms.

The AGM-88F has a GPS guidance added (with less accurate but jam-proof INS as a backup). The older AGM-88D also used GPS so that the missile, which normally homes in on radar transmissions, could be used to attack targets by location alone. The F model expands on basic GPS capabilities and also includes other features that assist in defeating enemy electronic defenses. What the GPS/INS provides is for a way for HARM to act on previous intelligence (about where an enemy radar is) while also using its radar signal homing capability and new anti-decoy features. Many countries now use a decoy emitter that sends out a fake radar signal to lure the HARM away from the real radar. The 88F model uses GPS and more sensors and new software to get around all known deceptions (and some that haven’t been invented yet).

The AGM-88 moves at high speed (2,200 kilometers an hour or 36 kilometers a minute). The original 1960s anti-radiation missile (ARM) quickly evolved into the HARM. Currently, there are orders for several thousand AGM-88E/Fs from the U.S. Navy and Marine Corps, Italy, Australia and Germany. The AGM-88 is used by the United States and 15 foreign nations. Over 24,000 AGM-88s, of all types, have been produced since the 1980s. Most are never used in combat or for training and are built for a long “shelf life”. Manufacturers have found ways to extend the shelf life of these expensive devices to a decade or more but often before that limit is reached new models of the missile appear with new features that are often essential to get the job done against enemies that have better countermeasures. For that reason, the trend is for guided missiles to be built to make it easier and cheaper to upgrade key components (like the guidance system, which is quite elaborate for a HARM missile). As time goes by successful missile designs result in more of the older models available to refurbishment and upgrades and this has become a major source of income for manufacturers.