Air-to-Ground Missiles: AGM-88 HARM
The AGM-88 HARM (High-speed Anti-Radiation Missile) is a tactical missile that targets electronic emissions from surface-to-air radar systems. Developed by Texas Instruments as a replacement for the AGM-45 Shrike and AGM-78 Standard ARM, the AGM-88 was first deployed in late 1985. The U.S. Air Force and Navy have both used the AGM-88, in particular during Operation Desert Storm. Capable of self-guidance requiring minimal human input, the AGM-88 can detect, target, and destroy a radar transmitter or antenna. The current version of the HARM is able to counter radar shutdown, passive radar, and active millimeter wave seekers.
Senior Airman Anthony Toliver, 22nd Expeditionanry Fighter Squadron weapons technician, secures an AGM-88 high-speed anti-radiation missile (HARM), at the end of of the runway after F-16CJ aircraft return to Incirlik Air Base, Turkey, 14 Jan 1999.
AGM-88 HARM Air-to-Ground Missile Development
During a test mission of the Air-to-Ground Weapons System Evaluation Program Combat Hammer, USAF Captain Thomas Seymour, Pilot, 86th Fighter Weapons Squadron, fires an AGM-88 High-speed Antiradiation Missile (HARM) from his F-16C Fighting Falcon at a target, Eglin Air Force Base, FL, 24 March 2003.
In 1969 the Naval Weapons Center began development of a new anti-radiation missile that operated fast enough to limit enemy radar's time to shut down emitters. Intended to replace the AGM-45 Shrike and AGM-78 Standard ARM, the missile project was dubbed HARM (High-speed Anti-Radiation Missile), and given the designation ZAGM-88A in 1970.
The new missile was designed with a larger warhead, broadband seekers, and operational flexibility. Texas Instruments Incorporated (TI) became the prime contractors, and first flight-tested a prototype, the AGM-88A, in 1975. By early 1980 problems with the prototype had been eliminated, and TI received the initial production contract.
The AGM-88A was powered by a Thikol SR113-TC-1 dual thrust solid rocket motor. It carried a WDU-21/B blast-fragmentation warhead in a WAU-7/B warhead section. The onboard seeker in the guidance section needed to be tuned to likely enemy frequencies during depot maintenance. As a result, each base or ship operating the HARM had variously tuned seeker heads.
The AGM-88 is controlled in flight by the WCU-2/B control section using four movable mid-body fins, and stabilized by the fixed tailfins. The AGM-88 also has an onboard inertial system allowing it to continue toward a target even if the emitter is shut down.
The AGM-88 has three operational modes. The Pre-briefed (PB) mode involves launching the missile on a lofted trajectory from a safe distance toward a known threat. Once the missile is in range of its intended target, it locks onto radar emissions and guides itself in. If the missile fails to achieve a lock, it self-destructs.
The Target of Opportunity (TOO) mode involves the AGM-88's onboard seeker identifying a target. The missile can then be fired manually if the proposed target is confirmed as a threat. The Self-Protect (SP) mode involves using the launch aircraft's radar warning receiver to detect enemy emissions, and subsequently fire the HARM. In both these modes, the HARM can be fired at targets behind the launch aircraft, though with limited range.
In 1983 the first production AGM-88A HARM missiles were delivered. The AGM-88 reached initial operational capability (IOC) with the U.S. Navy in 1985 and with the Air Force in 1987.
Early AGM-88As were classified as Block I. In 1986, the AGM-88A Block II, with a new seeker using software in an EEPROM, was introduced.
Weapons specialist TSGT William Clark, 169th Fighter Wing, South Carolina Air National Guard, McEntire Air National Guard Station, downloads an AGM-88 High Speed Anti-Radiation (HARM) missile, Hill AFB, UT, 17 July 2000.
The AGM-88B was introduced in 1987, with a Block II seeker and improved hardware in its guidance section, designed to be compatible with the forthcoming Block III software. This software improved in-flight reprogramming, as well as targeting in the PB mode. The Navy decided to keep its Block II missiles because the Block III update had to be performed with the missile fully powered up, an undertaking deemed too dangerous on aircraft carriers.
The AGM-88C became operational in 1993, with a new WDU-37/B warhead with far greater lethality. Also included was the Block IV software, designed to counter the newest threats. TOO mode performance was doubled as a result of improved seeker sensitivity. The AGM-88C-1 were HARMs built by TIs; the AGM-88C-2, by Loral Corporation, was tested but not produced in significant numbers.
A major software upgrade was the next improvement to the AGM-88. Designated Block V for the AGM-88C Block IV missiles and Block IIIA for older AGM-88B Block III missiles, this upgrade incorporated the ability to home in on jammers that interfered with GPS navigation. In 2000 the Navy began upgrading its AGM-88 inventory to Block IIIA/V.
The most recent software upgrade is known as Block VI. This upgrade is the result of collaboration among U.S., German, and Italian firms. The Block VI upgrade includes GPS navigation, greatly improving accuracy when enemy radar is switched off. In the U.S., AGM-88Cs that underwent the Block VI upgrade became known under the designation AGM-88D.
The latest variant of the HARM is the AGM-88E AARGM (Advanced Anti-Radiation Guided Missile). This variant includes further improvements to the Block VI missile, including a millimeter wave (MMV) active radar seeker for terminal homing. Development began at the Naval Weapons Center at China Lake, CA, in 1998. The first test-firing occurred in March 2000. ATK received a system development and design (SD&D) contract in May 2007. The missile will be equipped with a stealthy airframe for use in the F-22 and Joint Strike Fighter.
AGM-88 HARM Operational History
Aviation Ordnanceman 3rd Class Quentin Bryant, gives a thumbs up that an AGM-88 HARM missile is properly loaded to an F/A-18C Hornet aboard the aircraft carrier USS GEORGE WASHINGTON (CVN 73), deployed to the Persian Gulf in support of Operation Southern Watch, 19 Feb 1998.
The AGM-88 was first deployed in late 1985 with VA-72 and VA-46 on board the aircraft carrier USS America (CV-66). It was first used operationally against a Libyan SA-6 site in the Gulf of Sidra in March 1986, then in Operation El Dorado Canyon in Libya in April to defeat air defense networks during the bombing of Tripoli airfield, Benin airfield, and other targets.
The AGM-88B Block III was widely used in 1991 Gulf War, with over 200 missiles fired at Iraqi radar sites. During the Gulf War, an AGM-88 was involved in a friendly-fire accident. A F-4G Wild Weasel escorting a B-52 bomber mistook the bomber's tail gun radar for an Iraqi radar site, a result in part of the B-52 tail gunner erroneously targeting the F-4G as an Iraqi Mig. The F-4G pilot launched a HARM at the B-52, hitting the bomber but only causing shrapnel damage. The B-52 was then renamed 'In HARM's Way.'
The AGM-88 was used in Kosovo War, but often not deployed because missile was not sufficiently accurate to target radar installations deliberately placed near civilian areas.
The AGM-88 was used during the military intervention in Libya in 2011, known as Operation Odyssey Dawn, part of NATO's Operation Unified Protector.
Characteristics of the AGM-88 HARM
||Thiokol SR113-TC-1 dual-thrust rocket
||3 ft. 7 in.
||WDU-21/blast fragmentation in a WAU-7B; WDU-37/B blast-fragmentation
||Passive radar homing with home-on-jam; GPS/INS and EHF active radar (in E variant)
Note: Characteristics change slightly depending on the AGM-88 variant.
Recommended Books about Air-to-Ground Weapons and the AGM-88 HARM