The automated R2-D2 of the sea: how the Phalanx CIWS defends against incoming missiles

Cultures · Published 9 October 2026 Swipe more like this →

In short: Nicknamed after a Star Wars droid for its distinctive barrel-shaped radome, the Phalanx Close-In Weapon System is a self-contained, radar-guided Vulcan cannon. It acts as a ship's final line of defense, automatically detecting and destroying incoming missiles and small boats with a high-speed, computer-controlled stream of armor-piercing tungsten rounds.

Developed by General Dynamics and later Raytheon, the Phalanx CIWS was created to solve the problem of terminal defense against threats like sea-skimming missiles and maneuvering aircraft. The system is entirely self-contained, housing its own Ku-band fire-control radar, computer, and 20 mm M61 Vulcan rotary cannon within a single mounting. This autonomy makes it ideal for support vessels that lack integrated sensors. Since its approval for production in 1978, the system has evolved through several configurations, with the current Block 1B variant incorporating forward-looking infrared (FLIR) sensors to better track surface targets and low-flying threats.

The mechanism relies on two distinct radar antennas. A search antenna provides the CIWS computer with bearing, range, and velocity data to identify potential targets. Once a valid threat is confirmed—based on criteria like its trajectory toward the ship and its speed—the system hands the target to a highly precise tracking antenna. When the probability of a hit is maximized, the gun fires at a rate of 4,500 rounds per minute, using a computer-controlled system to 'walk' the rounds onto the target. Because it lacks identification friend or foe (IFF) capabilities, the system relies strictly on real-time radar data, which has occasionally led to accidental engagements of friendly assets.

Beyond naval use, the system was adapted for land as the Centurion, a key component of the Counter-Rocket, Artillery, and Mortar (C-RAM) initiative. Deployed in Iraq starting in 2005, the land-based variant protects forward operating bases by destroying incoming projectiles. Unlike the naval version, which uses armor-piercing tungsten rounds, the C-RAM utilizes high-explosive incendiary tracer rounds that self-destruct if they miss, minimizing collateral damage. While the system is a formidable defensive tool, its history of accidental discharges and friendly-fire incidents highlights the complexities of relying on automated, sensor-driven responses in chaotic combat environments.

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