South Korea Initiates $135.93M KDX-II Destroyer Upgrade to Boost Combat, Sonar, and Missile Systems

South Korea has officially launched an ambitious upgrade program for its Chungmugong Yi Sun-sin-class destroyers (KDX-II) to enhance their combat readiness and operational reliability. On January 15, the Defense Acquisition Program Administration (DAPA) convened a kickoff meeting to initiate the Performance Improvement Program (PIP), a comprehensive modernization effort focused on combat, sonar, and missile capabilities. This project, which involves a $135.93 million contract awarded to Hanwha Systems, is poised to extend the service life of the KDX-II fleet while integrating advanced domestic technologies.

Strengthening the Combat System

The Chungmugong Yi Sun-sin-class destroyers, which have been a cornerstone of the Republic of Korea Navy (ROKN) since their commissioning in the early 2000s, are undergoing a significant transformation. The upgrade includes replacing the aging combat systems with domestically developed technology that boasts advanced software, enabling faster target processing and enhanced information management. This marks a significant leap in the destroyers' capabilities, ensuring better preparedness against modern threats.

One critical improvement involves the integration of a new towed-array sonar system, similar to the one deployed on the state-of-the-art FFX Batch-III Chungnam-class frigates. This will bolster the destroyers' anti-submarine warfare capabilities, making them more effective in countering underwater threats. Additionally, upgrades to the missile illuminators for SM-2 surface-to-air missiles will strengthen the fleet's air defense systems, enabling more precise interceptions of aerial threats.

The United States is also playing a pivotal role in the program. The U.S. Department of Defense approved a $300 million Foreign Military Sale (FMS) in late 2024 to support the KDX-II upgrade. This includes critical components like the MK 99 fire-control system and software solutions, ensuring the destroyers meet modern operational standards.

Addressing Past Challenges

The urgency of the upgrade stems from repeated system failures in the KDX-II fleet. A prominent incident during the 2022 RIMPAC exercise saw the destroyer Munmu the Great fail to intercept a target with its SM-2 missile, which self-destructed mid-air due to a software error. Such incidents highlighted vulnerabilities in the weapon control systems, emphasizing the need for comprehensive modernization.

These destroyers have been in service for over two decades, with the lead ship commissioned in December 2003. Given their age and history of malfunctions, the performance improvement program is a critical step toward ensuring the fleet's operational reliability and mission readiness.

Specifications of the KDX-II Destroyers

The Chungmugong Yi Sun-sin-class destroyers are multi-role vessels designed for both offensive and defensive operations. Below are their key specifications:

• Displacement: 5,500 tons (full load)
• Dimensions: Length – 150m; Beam – 17.4m; Draft – 7.3m
• Propulsion: Combined Diesel or Gas (CODOG) system with 2 GE LM2500 gas turbines and 2 MTU diesel engines
• Speed and Range: Top speed of 30 knots; range of 5,500 nautical miles at 20 knots
• Crew: Approximately 230 personnel
• Combat System: SYQ-500K mod.II KDCOM2

Armaments

• 5-inch Mk 45 naval gun
• 30 mm Goalkeeper CIWS
• 8 RGM-84D Harpoon or SSM-700K C-Star anti-ship missiles
• 32-cell Mk41 VLS for SM-2 Block IIIA missiles
• 24-cell K-VLS for C-Star-II and Red Shark missiles
• Torpedo tubes for K745 Blue Shark torpedoes

Sensors and Sonar Systems

• RTX AN/SPS-49(V)5 2D long-range radar
• Thales Nederland MW08 3D radar
• Thales STIR 240 fire-control radar
• Atlas Elektronik DSQS-21BZ hull-mounted sonar
• SQR-220K towed-array sonar

Next Steps for the Fleet

Although the upgrade program excludes a radar replacement for now, future enhancements may address this gap. The inclusion of a domestically developed 3D AESA radar, such as the SPS-560K, or advanced systems like Lockheed Martin's SPY-7, remains a possibility in subsequent phases.

Meanwhile, the ROK Navy is also preparing for the eventual successor to the KDX-II class. At MADEX 2023, Hanwha Ocean unveiled the KDDX-S concept, a next-generation destroyer featuring automation, unmanned systems, and increased displacement.

A Legacy of Blue-Water Capabilities

Since their introduction, the KDX-II destroyers have played a pivotal role in transitioning the ROK Navy into a formidable blue-water force. Regularly deployed as part of the Escort Task Group in the Gulf of Aden, these vessels have safeguarded commercial shipping from piracy and other maritime threats.

With the modernization efforts now underway, South Korea’s KDX-II destroyers are set to remain a vital asset for the nation's maritime defense strategy, ensuring operational superiority and readiness for the challenges of modern naval warfare.