It was determined that KDX-II (Korea Destroyer Experiment) improvement project will be proceeded after improving the Gwanggaeto the Great-class destroyers (KDX-I), in contrast to the previous assumption that KDX-II upgrade would begin in 2018. This decision was made on the reason that the general update of the current KDX-II would negatively affect the ongoing plan to acquire the next-generation destroyer project which will be completed with Korean technology without any foreign assistance until mid-2030s, KDDX (KDX-IV), also called as “Korean Aegis” by the press.
In accordance with such a concern, the three 3,200 tons KDX-I destroyers, the flagships of each fleet in three seas around the Korean Peninsula since 1998, are being updated with the localized combat system software and new sensors. The destroyer Yangmanchun completed the capability improvement first in 2020, followed by the other two destroyers, Ulchi Mundok and Gwanggaeto the Great.
Unlike the KDX-I ships, KDX-II are 5,500t stealthy destroyers for operations in blue waters, fitted with the SM-2 Blocks 3/A surface-to-air missiles. It formed the concept of multi-layered air defense system for the first time in the world. A Chungmugong Yi Sun-sin-class destroyer is deployed near African waters twice a year as the Somali Sea Escort Task Group, called Cheonghae Unit. It has been one of the largest naval ships that the ROK Navy possesses with three-dimensional radars, MW-08.
However, the class was criticized for the lack of operational capabilities, particularly due to the limited number of simultaneous target engagement and firing range. The MW-08 radar was scheduled to be replaced by the Korean LIG Nex1’s SPS-550K which is installed on Incheon-class frigates, but it turned out by the Korean Navy that the replacement of its mast and radar would be technically and financially impossible because the SPS-550K is incompatible with the SM-2 missiles and the ships’ structure should be totally modified.
The analysis of the military and local media pointed out that such major replacement of onboard systems would require another complete overall change of KDX-II design which will approximately cost more than 1 billion dollar (1 trillion KRW), indicating that it would be much better to acquire new destroyers instead. The Defense Acquisition Program Administration (DAPA) and the Navy thus decided to focus on upgrading the anti-submarine warfare capability by changing its Towed Array Sonar System (TASS). Then, in the 133th Defense Project Committee on February 22nd in 2021, the DAPA changed the plan by additionally including the upgrade of KDX-II combat system based on domestic research and development. This changed schedule will last from 2022 to 2031, and the cost estimate is around 4.2 billion dollar (470 billion KRW).
As the DAPA already announced to develop next-generation destroyers in the KDDX project with Hyundai Heavy Industries (HHI) to ensure cost-efficiency, operational capabilities, and level of technical completion, the Korean local media interpreted that 6 KDDX will gradually replace the current KDX-II ships and the ROK Navy confirmed that a few of them will be assigned to its aircraft carrier flotilla in the future.
Talking to Naval News during MADEX 2021, a Junior Engineer of HHI who is specialized in surface ships planning, the DAPA has still been reviewing its business feasibility study as a lot of assets equipped on KDX-II destroyers were originally imported from foreign defense companies such as Thales and American defense firms. Thus, he added that the key goal of the KDX-II upgrade will be to develop alternative localized systems to lessen foreign dependence on defense capabilities.
However, when asked which option HHI would choose between improving the current TASS only or upgrading the destroyers generally, the engineer denied to answer by saying that details of the KDX-II improvement have not been specified yet, and that we would have to wait to know a fixed, specific date for such an update. An interview with him also confirmed that the upgrade agenda keeps changing its specifics due to other important businesses, although it is often said in his HHI meetings that it might begin soon.
The Lockheed Martin stand at MADEX 2021 features a KDX-II scale model with a new mast showing 4 SPY-1 radar arrays. This is a proposal for KDX-II destroyer upgrade.