US-Japan’s Joint Weapon, SM-3, to be Deployed in South Korea

Recently, our military authorities decided to introduce the SM-3 (Standard Missile-3). This sea-based missile defense interceptor can head off ballistic missiles at altitudes of 311 to 621 miles when mounted on a naval Aegis destroyer.

The SM-3 is a controversial weapon in South Korea, with divided opinions similar to those surrounding the Terminal High Altitude Area Defense (THAAD) system.

According to the initial Block 1A model’s performance, the SM-3, developed in the United States, boasts an interception altitude of 62 to 186 miles and a maximum flight range of approximately 311 miles.

The SM-3 was best known for cutting off missiles when Iran launched an airstrike against Israel with over 300 missiles and drones on the 13th, local time.

At the time, it was reported that the U.S. military assisted Israel and launched SM-3 missiles from a sea-based Aegis Combat destroyer and shot down more than three Iranian ballistic missiles.

The Defense Acquisition Program Administration (DAPA) held a Defense Acquisition Program Promotion Committee (DAPPC) meeting on the 26th and decided to purchase the SM-3 through a Foreign Military Sales (FMS) scheme referring to the incident.

According to the decision, the introduction of the SM-3 will occur from 2025 to 2030, and the total project cost is expected to reach $674 million.

DAPA announced the scheme to proceed with the project after confirming the appropriateness of the project promotion plan through a feasibility study by the end of this year.

The SM-3 possesses the most powerful force among the existing U.S. sea-based missile defense systems, with a range and impediment altitude far into space. The Block ⅠB model reaches a maximum range of 435 miles and a maximum interception altitude of 248 miles, and the Block ⅡA reaches a maximum range and interception altitude of 1,553 miles and 932 miles, respectively.

SM-3 can snatch even intercontinental ballistic missiles (ICBMs) to a limited extent and even destroy satellites with these capabilities.

The introduction of the SM-3 was first discussed in 2013 since South Korea lacked the means to intercept ballistic missiles if North Korea launched them at a high angle.

Despite several discussions, the SM-3 project did not make it to the DAPPC agenda and was returned to long-term review.

One of the main reasons for the SM-3’s failure to be introduced was China’s opposition. Various Chinese media outlets criticized the SM-3 as a sea-based THAAD and incited opposition to its introduction.

Even under the Moon Jae In administration, diplomatic efforts were made to improve Korea-China relations, which had soured after the deployment of the THAAD system, and the failure to discuss the introduction of the SM-3 was known to be one of these efforts.

In addition, Japan’s involvement was also a significant problem in introducing the SM-3 as the Block 2 type of SM-3 was co-developed by the U.S. and Japan. The controversy is expected to intensify depending on the purchase of a specific type as the military authorities have announced the intention to introduce the SM-3.

If the military authorities decide to purchase a co-developed missile by the U.S. and Japan, that decision would have a significant impact on Korean politics and Korea-Japan relations.

Considering the current sensitivity in Korean politics and society towards military cooperation with Japan, bringing in Japanese weapons could be seen as supporting Japan’s militarization.

Regardless of the choice, the military authorities cannot avoid domestic and international controversy involving China and Japan.

Initially, the THAAD system was criticized for its limitations in defending the entire Korean peninsula, as only one battery was deployed in Seongju, North Gyeongsang Province, to intercept missiles at altitudes of 24 to 93 miles.

However, introducing the SM-3 will result in performing interception tasks from the mid-course (altitude above 62 miles) once a North Korean missile has been launched and begins to descend.

In addition, even if an attempt to intercept at the mid-course fails, the interception opportunity will increase as multiple attempts at multiple stages can be made with terminal stage upper and lower interception weapons such as L-SAM, M-SAM, and Patriot, which is expected to greatly assist in building a defense network system.

However, there is also a view that the introduction of the SM-3 did not consider the battlefield environment of the Korean Peninsula. Since the missiles that the North Korean military uses to attack South Korea are mainly short-range ballistic missiles (SRBMs) with low altitudes, there is an argument that the SM-3 is unnecessary.

Also, there is concern that our military’s introduction of the SM-3 signifies joining the U.S. Missile Defense system (MD).

In response to these negative public opinions, DAPA stated that the introduction of the SM-3 is separate from the MD system and intended to reinforce the Korean Air and Missile Defense (KAMD) mid-course. The military utility of the SM-3 has been secured through requirement verification, and objectivity will be secured through a feasibility study.

Meanwhile, there is also a high possibility that a Korean version of the SM-3 could be developed quickly. Since the military authorities mentioned reviewing the SM-3 level in 2018, there is a chance of operating a missile designed to the level of the SM-3, not simply purchasing and operating.

However, with weak competence in the space science industry, exploring SM-3-level missiles seems complicated.