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Phalanx Close-In Weapons System

Updated: 24 January 2004

Description: Fast-reaction, rapid-fire 20-millimeter gun system.

Features: Phalanx provides ships of the U.S. Navy with a "last-chance" defense against anti-ship missiles and littoral warfare threats that have penetrated other fleet defenses. Phalanx automatically detects, tracks and engages anti-air warfare threats such as anti-ship missiles and aircraft, while the Block 1B's man-in-the-loop system counters the emerging littoral warfare threat. This new threat includes small,high-speed surface craft, small terrorist aircraft, helicopters and surface mines. Phalanx accomplishes these engagements via an advanced search and track radar system integrated with a stabilized, forward looking infra-red (FLIR) detector. This integrated FLIR provides Phalanx with an unique multi-spectral detect and track capability for littoral warfare threats and dramatically improves the existing anti-air warfare capability. Block 1B also incorporates new Optimized Gun Barrels which provide improved barrel life, improved round dispersion and increased engagement ranges.

Phalanx is the only deployed close-in weapon system capable of autonomously performing its own search, detect, evaluation, track, engage and kill assessment functions. Phalanx also can be integrated into existing Combat Systems to provide additonal sensor and fire-control capability.

Background: The Phalanx Close-In Weapons System (CIWS) underwent operational tests and evaluation onboard USS Bigelow in 1977, and exceeded maintenance and reliability specifications. Phalanx production started in 1978 with orders for 23 USN and 14 Foreign Military Sales (FMS) systems.

Point of Contact:
Public Affairs Office
Naval Sea Systems Command (OOD)
Washington, DC 20360

General Characteristics

Primary Function: Anti-ship missile defense
Contractor:Raytheon Systems Company (formerly Hughes Missile Systems Company and purchased from General Dynamics Pomona Division in 1992)
Weight: 12,500 pounds (5,625 kg) - Later models: 13,600 pounds (6,120 kg)
Range: Classified
Gun Type: M-61A1 Gatling
Type of Fire: 3,000 rounds per minute - Later models: 4,500 rounds/min (starting 1988 production, Pneumatic Gun Drive)
Magazine Capacity: 989 rounds - Later models: 1,550 rounds
Caliber: 20mm
Ammunition: Armor Piercing Discarding Sabot (APDS), Depleted Uranium sub-caliber penetrator. Penetrator changed to Tungsten 1988. Block 1B will incorporate the new Enhanced Lethality Cartridge with a heavier penetrator.
Sensors: Self-contained search and track radar with integrated FLIR
Date Deployed:
1980 (aboard USS Coral Sea)
Block 1: 1988 (aboard USS Wisconsin)
Block 1B: 1999 (aboard USS Underwood)

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