During the Vietnam War, the US Air Force and US Navy for the first time had to contend with the threat of Soviet SAM systems. They eventually devised a counter, in the form of the AGM-45 Shrike anti-radiation missile. Unfortunately, the Shrike was slow, fairly dumb and hard to use, and this was costing pilots their lives. The military needed an answer, and fast.

The Navy started research, using a slightly modified version of their RIM-66 Standard SAM. It wasn't difficult to modify its semi-active seeker to act as a passive seeker instead, and add a small circuit to hold its course in the event that the enemy switched off their radar. With the Shrike, if the enemy deactivated their radar, as they often did, the missile would lose control and fly randomly, crashing uselessly or self-destructing. This new ARM avoided that - if it lost the radar signal it was homing in on, it would keep flying to its last known target position. Because of the re-use of existing hardware, and minor modifications required, the Standard ARM was in service less than 18 months after development began.

Another problem with the Shrike was its tendency to only destroy the dish of the SAM radar. The much larger RIM-66, on the other hand, would deliver both more kinetic energy and more explosive to its target, increasing the probability of destruction. On the downside, however, the Standard ARM was much more expensive than the Shrike, per shot.

Surface-launched versions of the AGM-78, designated RGM-78, were developed for shipboard use as anti-ship missiles, and for truck launch against nearby SAM sites. The latter configuration was only used by Israel, and was called Keres by the IDF. A later version, introduced in 1976, added a still larger warhead.

The last of the AGM-78 missiles procured for the Air Force and Navy were expended in the 1980s, and it was replaced by the AGM-88 HARM.

AGM-78 Standard ARM

  • Contractor: Raytheon
  • Length: 15 ft (4.57 m)
  • Wingspan : 3 feet 3½ in (1.08 m)
  • Weight : 1,350–1,800 lb (620–815 kg) depending on model
  • Propulsion : Dual-thrust solid fueled rocket
  • Warhead : 100 kg (220 lb) blast-fragmentation type (1976 variant)
  • Fusing : Active optical proximity type
  • Range : Up to 90 km (56 statute miles)
  • Velocity : Up to Mach 2.0

Log in or register to write something here or to contact authors.