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|Copyright © 2002 Andreas Parsch|
The AGM-78 Standard ARM (Anti-Radiation Missile) was a development of the RIM-66 Standard shipborne air-defense missile. It supplemented the AGM-45 Shrike, but like the latter has been replaced by the AGM-88 HARM.
In 1966, it had become clear that the AGM-45 Shrike was far from the ideal anti-radiation missile, its main problems being the limited range, small warhead, and unflexible seeker. The Naval Air Systems Command issued a contract to General Dynamics to develop an air-launched ARM variant of the successful RIM-66 Standard missile, and assigned the designation ZAGM-78A to the project. Because no completely new components had to be developed, progress was quick, and after trials in 1967, the AGM-78A production version became operational with the USAF and U.S. Navy in early 1968.
|Photo: via FAS|
|AGM-78 (exact model unknown)|
The original AGM-78A-1, which was also known to the U.S. Navy as STARM (Standard ARM) Mod 0, was nothing more than an air-launched variant of the RIM-66A, fitted with the anti-radar seeker of the AGM-45A-3A. It was powered by an Aerojet MK 27 MOD 4 dual-thrust solid rocket, and had a blast-fragmentation warhead. The AGM-78A-2 added a BDA (Bomb Damage Assessment) capability, and an SDU-6/B red phosphorus target marker to mark the target for further strikes. In addition to the longer range and bigger warhead, another advantage over the Shrike was the gimballed seeker of the AGM-78, which permitted a wider range of manoeuvers for the launching aircraft. However, the AGM-78 was also much more expensive than the AGM-45, and could therefore not completely replace the latter. The carrier aircraft for the AGM-78A were the USAF's F-105F/G (using LAU-78/A launchers) and the USN's A-6B/E (using the LAU-77/A). An inert training version of the AGM-78A was built as ATM-78A.
In 1969, production switched to the improved AGM-78B (a.k.a. STARM Mod 1), which was to become the most important variant. It featured a new broadband seeker by Maxson, enabling the usage of the Standard ARM against many different types of targets without the need to pre-select a seeker. The AGM-78B also had a simple memory circuit, so that it could home on a previously locked target even after emitter shut-down. Some early AGM-78A-1s, which were upgraded with the Maxson seeker and memory circuit, were known as AGM-78A-4. The AGM-78B was one of the main weapons of the Air Force's F-4G aircraft. There was also an ATM-78B training variant of the AGM-78B.
|Photo: Phil Callihan|
The AGM-78C, built between 1970 and 1972, was mainly a USAF program. It was a variant of the AGM-78B with lower production costs and higher reliability, and it also had a new SDU-29/B white phosphorus target marker. Some AGM-78A/B missiles were upgraded to AGM-78C standard. The final version of the Standard ARM was the AGM-78D, built between 1973 and 1976. It had a new MK 69 MOD 0 motor. The ultimate AGM-78D-2 also featured greater digital reliability, an active optical fuze, and a new 100 kg (223 lb) blast-fragmentation warhead. The ATM-78C and ATM-78D were the inert training versions of the AGM-78C and D, respectively.
The shipborne anti-radiation missile RGM-66D combined features of the RIM-66 and AGM-78 missiles, and the AIM-97 Seekbat high-altitude air-to-air missile was based on the AGM-78 airframe.
More than 3000 AGM-78 missiles of all versions were built. The Standard ARM was removed from the U.S. inventory in the late 1980s, having been completely replaced by the AGM-88 HARM.
Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!
Data for AGM-78B:
|Length||4.57 m (15 ft)|
|Finspan||108 cm (42.5 in)|
|Diameter||34.3 cm (13.5 in)|
|Weight||620 kg (1370 lb)|
|Range||90 km (56 miles)|
|Propulsion||Aerojet MK 27 MOD 4 dual-thrust solid-fueled rocket|
|Warhead||97 kg (215 lb) blast-fragmentation|
 Anthony Thornborough: "Iron Hand", Sutton Publishing, 2001
 Norman Friedman: "US Naval Weapons", Conway Maritime Press, 1983
 Bill Gunston: "The Illustrated Encyclopedia of Rockets and Missiles", Salamander Books Ltd, 1979
 Christopher Chant: "World Encyclopaedia of Modern Air Weapons", Patrick Stephens Ltd., 1988
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