South Korea unveils KSAM-II surface-to-air missile to replace US-made SM-2s on KDDX destroyers.

On July 14, 2026, South Korea's LIG Nex1 unveiled the initial KSAM-II surface-to-air missile production line at Plant 3 in Gumi, North Gyeongsang Province. The facility establishes domestic production capability for the 6-meter naval interceptor designed to replace the U.S.-built SM-2 aboard future KDDX destroyers and FFX Batch IV frigates. Committing industrial infrastructure prior to flight-test qualification mitigates potential operational capability gaps between ship deliveries and missile availability.

The KRW 690 billion KSAM-II program runs from 2023 to 2036, with initial flight-test missile production supporting over ten planned firing trials before operational deployment. Built around a 1 kW Gallium Nitride active radar seeker and capable of 100 target updates per second at Mach 5, the interceptor provides local defense against supersonic cruise missiles and aerodynamic threats.

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Compared with the SM-2, the KSAM-II is designed to spot smaller missiles, react faster, and reduce South Korea's dependence on imported U.S.-made missiles. (Picture source: X/Mason ヨンハク)

On July 14, 2026, Daum reported that South Korea's LIG D&A unveiled the first KSAM-II surface-to-air missile at Plant 3 in Gumi, North Gyeongsang Province. The missile, which measures approximately 6 m, will replace the US-made SM-2 aboard the future KDDX destroyer and FFX Batch IV frigate. The programme runs from 2023 to 2036 and is estimated at around KRW 690 billion, although actual spending will be concentrated around development, testing, initial production and ship integration. Production of the first flight-test missiles was scheduled to begin in July 2026, three years after the K-SAM-II's development was approved by the Defense Acquisition Program Administration (DAPA) and around two years after LIG Nex1 was selected in October 2023.

These test missiles will support more than ten firing trials before series-produced missiles can be loaded aboard operational ships. The schedule is also closely tied to the KDDX, whose first ship is now scheduled for delivery at the end of 2032, leaving approximately six years between the first test-round production and the planned arrival of the initial missile carrier. The requirement was established in April 2017, when the DAPA approved the Korean Ship-to-Air Missile-II (KSAM-II) program as a new long-term naval requirement. Requirement validation and feasibility assessments followed in 2021 and 2022, after which the Defense Acquisition Program Promotion Committee approved the development plan in March 2023. DAPA issued the request for proposals on July 14, 2023, and selected LIG Nex1 in October 2023 after evaluating the competing proposals from LIG Nex1 and Hanwha Aerospace.

The production facility was completed on March 5, 2026 and opened for its first media visit on July 14, exactly three years after the request for proposals. The decision to establish the line before qualification is complete reflects a schedule driven by the KDDX construction and the need to avoid a gap between ship delivery and missile availability. It also transfers part of the program risk into the industrial phase because tooling, buildings, inspection equipment and supply arrangements have been committed before the missile has completed its firing campaign. If qualification identifies a structural, seeker, propulsion or software deficiency, the correction may have to be introduced into an operating production line rather than resolved before manufacturing infrastructure is established.

According to available information, the KSAM-II measures approximately 6 m and is divided into three major sections. The forward section contains the seeker and guidance electronics, including the equipment needed to receive target data, estimate target movement, calculate an interception course, and control the missile during flight. The central section contains the main propulsion unit and warhead, while the rear section contains the booster that produces the initial thrust after launch from the vertical cell. Manufacturing is divided into approximately twenty stages and requires around three months from the start of assembly to completion of a missile. More than twenty personnel participate in the process, which includes mechanical assembly, cable and electronic installation, propulsion integration, alignment, inspection and functional testing.

The Gumi facility uses four principal assembly and inspection spaces separated by reinforced walls more than 60 cm thick to diminish the risk in case of a blast event. The production building has an internal height of approximately 8 m and uses around thirty types of assembly fixtures, stands, and dedicated tools. The missile seeker is the most important identifiable change from earlier South Korean naval interceptors. The KSAM-II uses a third-generation active radar seeker built around a 1 kW Gallium Nitride (GaN) solid-state power amplifier. The first-generation South Korean seeker was used for the Cheongung, while the L-SAM introduced the second generation, and the KSAM-II moves to a higher-power and faster-processing configuration.

Gallium Nitride (GaN) permits a radar transmitter to operate at higher power density and temperature than older semiconductor materials, which is relevant inside a missile nose where aperture size, electrical supply, and cooling capacity are limited. The minimum target dimension associated with the seeker has reportedly fallen from 1.4 m for the first generation to 0.3 m for KSAM-II, a reduction of approximately 79%. The figure should not be interpreted as a universal detection guarantee because effective detection also depends on radar cross-section, aspect angle, target material, altitude, sea state, electronic countermeasures and the quality of target information supplied by the ship. Its importance lies in the relative change: South Korea is attempting to improve the missile’s ability to retain a terminal track on targets that provide weaker radar returns and remain close to the sea surface.

The KSAM-II missile’s onboard processor updates the target track and recalculates the interception path 100 times per second, producing one new solution every 0.01 seconds, five times faster than the SM-2. Faster computation is useful when the target changes heading, altitude, or velocity during the terminal phase because an interception point calculated only a fraction of a second earlier may no longer be valid. At Mach 5, the KSAM-II would travel approximately 1.5 to 1.7 km each second depending on altitude and atmospheric conditions. During the 0.01-second interval between calculations, the missile itself could move roughly 15 to 17 m, which illustrates why high update rates and control precision are necessary at that velocity. The airframe is also intended to tolerate loads of 17 g, equivalent to approximately 167 m/s² of acceleration, during high-speed maneuvering.

Qualification therefore has to establish that the seeker, electronic boards, warhead interfaces, rocket motor joints and control mechanisms continue operating after launch shock, vibration and repeated maneuvering loads. The missile’s stated threat set includes aircraft and cruise missiles, particularly small supersonic cruise missiles, rather than ballistic missiles. A different interceptor, the KSAM-II ABM, is being developed for ballistic missile interception because the required altitude, closing speed, maneuver profile and kill mechanism differ from those needed against aerodynamic targets. The KSAM-II is based on the L-SAM-I anti-aircraft missile, which allowed LIG Nex1 to reuse a substantial part of South Korea’s land-based long-range air defense technology.

The development shortcut concerns propulsion, flight control, active radar guidance and computational architecture, but converting the missile for naval use remains more complex than fitting the land interceptor into a shipboard canister. A naval missile must tolerate long storage in a humid and saline environment, continuous vibration from propulsion machinery, shock from gunfire or nearby explosions, ship movement during launch and electromagnetic interference from multiple high-power radars and transmitters. It must also interface with a combat management system that may be tracking hundreds of air and surface contacts while simultaneously assigning weapons and managing communications. The KSAM-II will normally receive the ship’s target data before launch and during the early or middle portion of the flight, then use its active seeker during terminal interception.

This architecture differs from the semi-active guidance used by established SM-2 variants, which require the ship to illuminate the target during the terminal phase. An active terminal seeker can reduce dependence on dedicated illumination channels and permit more simultaneous engagements, but only if the KDDX’s radar and data-link architecture can provide sufficiently accurate mid-course information to place the KSAM-II within the seeker’s acquisition volume. The KDDX is a class of six guided-missile destroyers planned to be developed between 2020 and 2036 at a combined estimated cost of KRW 7.8 trillion, including approximately KRW 1.8 trillion for development and KRW 6 trillion for construction.

The class has a full-load displacement of about 9,000 tonnes, with a length of 159 m, a beam of 20 m and a crew of 158. Its planned armament includes a 127 mm gun, eight anti-ship missiles, 48 K-VLS I cells and 16 K-VLS II cells, although models shown during the design process have also displayed a reduced configuration of 32 forward cells and 16 aft cells. The ship’s integrated mast combines fixed S-band and X-band active electronically scanned array radars. Four fixed faces provide 360-degree coverage, while the division between bands allows the S-band system to concentrate on longer-range air and ballistic-target detection and the X-band system to support more precise tracking of low-altitude and surface targets. The S-band radar will contain approximately 4,096 transmit-receive elements, compared with about 4,350 in the AN/SPY-1D(V).

In June 2026, Hanwha Ocean was selected as the preferred negotiating party for detailed design and construction of the lead ship, which DAPA expects to deliver at the end of 2032. Compared with the first Korean vertical-launch system, the K-VLS II's footprint has been enlarged to 180%, its cell length to 120% and its allowable weapon load to 185%. Put differently, the K-VLS II occupies 80% more deck area, is 20% longer and can accept 85% more weapon mass than the preceding launcher. The KDDX is not currently planned to carry the U.S. Mk 41 launcher, making the successful integration of the KSAM-II into K-VLS II cells a programme requirement rather than an optional national substitute. The missile will share the ship’s vertical-launch capacity with other Korean weapons, including the Red Shark anti-submarine torpedo and the Haeryong land-attack missile.

A nominal sixty-four-cell arrangement would therefore not translate into sixty-four KSAM-II rounds because the ship must reserve cells for anti-submarine warfare, surface or land attack, and potentially other air-defense weapons. A load of sixteen long-range interceptors, for example, could be consumed in eight two-missile engagements, while allocating thirty-two cells to KSAM-II would reduce space available for other missions. Actual doctrine, salvo size, and magazine composition have not been disclosed, but the fixed number of cells creates a measurable operational constraint. The KSAM-II is also intended to change the cost and sustainment structure of South Korea's naval air defense. The South Korean Navy currently uses US-made SM-2 on Chungmugong Yi Sun-sin-class destroyers and Sejong the Great-class Aegis destroyers, while it is also acquiring SM-6 and has decided to procure SM-3 for higher-altitude ballistic-missile defense.

However, the SM-2 production stopped in 2013 because of insufficient international demand and restarted in 2017 for orders from South Korea, Japan, Australia and the Netherlands, illustrating the risk created when an imported missile depends on a foreign production decision. Currently, South Korean concerns involve the SM-2’s unit cost, maintenance expenditure and upkeep requirements as well as performance. The KSAM-II does not eliminate cost because South Korea must fund development, qualification, production tooling, depot support, spares and periodic recertification, but it gives the country greater control over production timing, repair work, component replacement and software modification. The KRW 690 billion programme total cannot be divided into a credible cost per missile because it includes development and integration expenditure and because the procurement quantity remains unknown.

The investment becomes stronger if the KSAM-II is ordered for all six KDDX destroyers and the future FFX Batch IV frigates, since a larger fleet would logically distribute fixed development and support costs across more missiles and more launch platforms. The KSAM-II will also form the outer air defense layer of a larger national missile family. The KSAM-II ABM is being planned around the M-SAM-III interceptor to engage ballistic missiles from ships, while the K-SAAM-II is being developed as a shorter-range weapon, potentially occupying the role filled by the RIM-162 Evolved Sea Sparrow Missile (ESSM).

Therefore, the KSAM-II must reach aircraft and cruise missiles at long distances, the KSAM-II ABM ballistic targets at greater altitude, and the K-SAAM-II must provide a less costly weapon for shorter-range engagements where using a large long-range interceptor would be inefficient. The resulting KDDX air defense structure could therefore combine KSAM-IIs for outer-area defense, K-SAAM-IIs for the intermediate layer, and CIWS-II for the final few kilometers, while separate SM-3 or KSAM-II ABM missiles address ballistic targets. The central risk is that a delay in any one of them can postpone the KDDX's operational capability even if the others are technically complete. South Korea is therefore trying to build a complete indigenous naval air defense architecture over a period of roughly nineteen years, rather than conducting a simple one-for-one purchase to replace a U.S.-made missile.

Written by Jérôme Brahy

Jérôme Brahy is a defense analyst and documentalist at Army Recognition. He specializes in naval modernization, aviation, drones, armored vehicles, and artillery, with a focus on strategic developments in the United States, China, Ukraine, Russia, Türkiye, and Belgium. His analyses go beyond the facts, providing context, identifying key actors, and explaining why defense news matters on a global scale.

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