The Standard Missile 2 (SM‑2) is a key surface-to-air missile for the US Navy, forming the core of fleet area air defense and ship self-defense at medium to long ranges.

Equipped with a blast-fragmentation warhead and radar/contact fuse, the SM-2 provides protection against anti-ship missiles and aircraft, as well as threats flying close to the water's surface.

While the SM-2 is primarily deployed for fleet area air defense and ship self-defense, it also can be used in a limited capability to engage surface vessels.

Integrated into the Aegis Weapon System aboard Ticonderoga-class cruisers and Arleigh Burke-class destroyers, SM‑2 missiles are also fielded by allied navies including Australia, Japan, the Netherlands, Germany and Spain.

Variants include the SM‑2, SM‑3 (anti-ballistic) and SM‑6 (extended-range active), enabling multi-tiered naval air defense.

The SM-3 is designed for exo-atmospheric interception of ballistic missiles in the mid-course phase of flight, while the SM-2 is used to engage aircraft and cruise missiles in the terminal phase. The SM-6 provides over-the-horizon defense.

These interceptors are launched from the Mk 41 vertical launching system (VLS) and leverage blast-fragment warheads to destroy their targets.

US Navy cruisers and destroyers use the Aegis Combat System to integrate the SM-2, SM-3, SM-6, Evolved Sea Sparrow Missile (ESSM) and other defense systems.

The Aegis Combat System uses a complex array of radars and sensors to track, identify and destroy adversary targets, defending naval ships against hostile aircraft and cruise missile threats.

This system, and its ability to link sensor data from multiple sources and missiles, are what give Arleigh Burke-class destroyers their edge in combat.

The ability to intercept low-flying threats, cruise missiles and aircraft at extended ranges directly supports the US military's layered air and missile defense.

Block upgrades

Ongoing modernization of missile variants ensures US naval forces and partners maintain credible deterrence amid evolving regional threats.

The SM-2 has evolved through several upgraded variants, each designed to meet the shifting demands of modern naval warfare.

The Block III series -- III, IIIA and IIIB -- offers medium-range performance of approximately 166km and employs a semi-active radar homing system.

Blocks IIIA and IIIB introduced more advanced guidance capabilities, using both continuous-wave and interrupted continuous-wave radar seekers to improve accuracy and adaptability.

The Block IIIB variant further enhanced targeting with autonomous infrared acquisition, allowing the missile to hone in on low-signature threats or adversaries using electronic countermeasures.

The latest Block IIIC seeker modernization program includes a dual-mode semi-active/active seeker.

The SM-2 Block IV has even greater range and area coverage, with dual-stage propulsion and an advanced semi-active radar seeker, extending its reach to between 185 and 370km.

Together, these variants form a layered and adaptive defense framework capable of countering a wide range of aerial and surface threats.

Real‑world validation

The US Navy's most advanced destroyer, USS Zumwalt, conducted its first-ever live-fire of a Standard Missile-2 (SM-2) Block IIIA in October 2020.

Launched from the ship's Mk 57 VLS during a test off the coast of Point Mugu, California, the missile successfully intercepted and destroyed a subsonic cruise missile surrogate.

The test served as a critical validation of several key onboard systems, including the AN/SPY-3 radar, the VLS, Cooperative Engagement Capability (CEC), and the ship’s highly integrated Total Ship Computing Environment.

Together, these systems enable Zumwalt to detect, track and engage aerial threats with a level of automation and coordination not seen in earlier platforms.