What feature is the primary characteristic of the Mk 15 Phalanx CWIS?

The primary characteristic of the Mk 15 Phalanx Close-In Weapon System (CWIS) is its fast-reaction, detect-through-engage system. This feature enables the Phalanx to automatically acquire, track, and destroy incoming threats such as missiles, aircraft, and small boats. The system is designed to respond quickly to threats that other defensive systems might not be able to engage in time, using a high rate of fire from its Gatling gun to provide defense at close range.

The detect-through-engage capability is essential in modern naval warfare, where threats can arise rapidly and unexpectedly. The Phalanx utilizes onboard radar and fire control systems that allow for immediate reaction, ensuring that a ship can protect itself effectively in a combat environment.

Other options do not accurately represent the core function of the Phalanx. While radar-guided missile capabilities are important in many modern weapons systems, the Phalanx is primarily designed for close-in defense rather than engaging distant targets. Drone strike technology and submersible operation abilities do not pertain to the characteristics or functionality of the Phalanx, as it is specifically designed for surface engagements aboard naval vessels.