On 21 October 1967, during the Arab-Israeli "Six Day War," three Soviet-designed SS-N-2 "Styx" missiles from two Egyptian-manned, Soviet-supplied Komar-class missile craft attacked and sank the Israeli destroyer INS EILAT (K40) off Port Said, Egypt. EILAT was the ex-HMS ZEALOUS (R39), a former British World War II destroyer of the "Z" class.

The sinking of the EILAT caused a major panic among the world's navies and kicked point-defense systems into high gear. Until the EILAT's sinking, fleet air defense had concerned itself with the destruction of attacking manned aircraft. Defeating a small, fast, low-flying threat represented by an unmanned cruise missile was a completely different story and warships were not defended against this threat. Worse, these anti-ship missile (ASM) systems could be fielded and operated by small countries.

The attacked - INS EILAT (K40) [ex-HMS ZEALOUS (R39)] as she was at the time of the Arab-Israel Six Day War. Photograph: Israeli Navy. The attackers - two Komar missile attack craft of the United Arab Republic (Egyptian) Navy. Photograph: UAR Navy. The attack on EILAT of 21 October 1967 - from the Egyptian newspaper "Al Gomhoreya" - with English captions from the Arabic. Art: "Al Gomhoreya" via Bob Stoner.

The Navy approached ASM defense as both a surface-to-air (SAM) missile problem and as a gun problem. The first SAM system specifically designed to deal with the ASM problem was the Basic Point Defense Missile System or BPDMS. The BPDMS was first tested aboard USS BRADLEY (FF-1041) in February 1967. The BPDMS used eight modified RIM-7E Sea Sparrow missiles in an eight-cell Mk 25 launcher that was a scaled-down version of the Mk 112 launcher for the ASROC (Anti-Submarine Rocket). The Mk 115 fire control radar system provided targeting for the RIM-7E. Missile range was about 10 to 16 miles with a 65-pound high explosive, continuous rod warhead.

The Basic Point Defense Missile System (BPDMS) was composed of the Mk 115 fire control director and Mk 25 launcher. The Mk 115 director was a manned system as shown in this photo taken aboard USS DWIGHT D. EISENHOWER (CVN-69). Photograph: U.S. Navy. The Mk 25 launcher for Sea Sparrow aboard the Knox-class frigate USS JOSEPH HEWES (FF-1078.) Photo: Tom Oshgan.

Meanwhile, General Dynamics Corporation, Pomona Division, started with the Army's self-propelled M163 Vulcan Air Defense System (VADS) to produce an automated version for naval service. This new weapon was called Vulcan-Phalanx (later shortened to just Phalanx). The prototype Phalanx was installed aboard USS KING (DLG-10/DDG-41) in 1973 for evaluation. Another prototype CIWS was used in tests conducted aboard ex-USS ALFRED A. CUNNINGHAM (DD-752). Several different kinds of missiles were fired at CUNNINGHAM; all were shot down. Full operational and evaluation trials were performed aboard USS BIGELOW (DD-942) in 1977. The evaluations included tests with high levels of jamming noise during which the unit succeeded in distinguishing small missile-like targets against nearby islands.Phalanx met and exceeded all maintenance and reliability requirements. The first production units of Phalanx were installed aboard USS CORAL SEA (CV-43) in 1980. Installation aboard noncombatant ships began in 1984. Block 1 was deployed aboard USS WISCONSIN (BB-64) in 1988. Block 1B was deployed aboard USS UNDERWOOD (FFG-38) in 1999 and was operational aboard USS TAYLOR (FFG-50) in 2000.

The M163 Vulcan Air Defense System (VADS) as installed on the M113 armored personnel carrier. This M163 VADS of the 24th Infantry Division is shown at the Fort Irwin National Training Center on 1 November 1988. Photograph: U.S. Army. The very first Phalanx prototype aboard USS KING (DLG-10/DDG-41). The gun was located on the fantail of the ship as shown in the insert. Kill markings are stenciled on the radome for the search and fire control radars. Photograph: Mark Donovan, USS King Association. A production Phalanx Block 1A firing. Note the enlarged ammunition drum and different gun support yokes that support the gun and radome. Photograph: U.S. Navy.

The Falklands War between the UK and Argentina in 1982 raised further questions about the effectiveness of ASM defense. In that war, several British ships were struck by French-built Exocet ASMs. To find out how well Phalanx would handle this kind of threats, the latest version of the Mk 15 Mod 0 Phalanx, called the Block 0, was installed aboard the test ship ex-USS STODDARD (DD-566) in November 1983. A year long round of real world tests against all kinds of targets - including live warheads - were undertaken. Lessons learned from these tests were incorporated into the Block 1 version of Phalanx. Further tests from June 1985 through early 1990 against Block 1 Phalanx were conducted aboard STODDARD that led to Block 1, Baseline 1 and 2 improvements. These tests led to the development of the Block 1A variant that introduced an updated computer with software designed to engage targets doing high-G and diving maneuvers.