Questions raised on price of missile surveillance without blind spots
South Korea suspended the continuous deployment of Aegis destroyers in the East Sea in September last year, raising concerns that the decision could limit the military's ability to gather detailed flight data on North Korean missiles as Pyongyang continues to test an increasingly diverse range of weapons.
The military says its existing surveillance assets are sufficient to sustain missile detection, tracking and defense readiness. But some officials have raised concerns about reduced opportunities to gather detailed missile intelligence, arguing the capabilities needed for missile defense should be distinguished from those required to assess North Korean missile performance.
According to multiple military sources, the Navy requested approval from the Joint Chiefs of Staff in September 2025 to suspend the continuous deployment of Aegis destroyers in the East Sea, citing personnel shortages and the operational burden of keeping warships at sea for extended periods. The JCS approved the request.
At the time, the JCS was headed by Gen. Kim Myung-soo, a Navy officer who was succeeded by Air Force Gen. Jin Yong-sung on Sept. 30, 2025.
South Korea currently operates four Aegis destroyers equipped with advanced radar systems capable of detecting and tracking ballistic missiles over long distances, making them key maritime surveillance assets.
At the time of the continuous deployment proposal, the Navy counted three Aegis destroyers in its fleet.
Following the suspension, the Navy was reportedly expected to dispatch Aegis destroyers when indications of an impending North Korean missile launch were detected, rather than maintaining a continuous presence in the East Sea.
"The original plan, as I understand it, was to dispatch Aegis destroyers when signs of an impending North Korean missile launch were detected," a military official said, speaking on condition of anonymity. "But North Korea has increasingly launched missiles without clear advance indications."
North Korea's evolving missiles complicate monitoring efforts
North Korea has recently conducted a series of tests involving different missile systems, underscoring the growing importance of collecting flight data to assess their performance and characteristics.
On Oct. 29, Pyongyang fired multiple rounds from its 600 mm super-large multiple-rocket launchers. It subsequently claimed to have tested a tactical ballistic missile equipped with a cluster warhead on Oct. 31, followed by tests assessing the effectiveness of a cluster warhead on a strategic cruise missile and its vertical-strike flight characteristics on Nov. 2.
On Wednesday, North Korea launched several missiles toward the East Sea from the Sondok area of South Hamgyong Province.
In its initial announcement, the JCS described the projectiles simply as "missiles," without identifying them as ballistic missiles. It added that South Korean and US authorities examined their specifications, considering possibilities including close-range ballistic missiles, surface-to-air missiles and cruise missiles.
The following day, North Korea's state-run Korean Central News Agency reported that the country had conducted a test launch of a new surface-to-air missile and a live-fire exercise involving long-range strategic cruise missiles.
A separate military official said identifying projectiles based on radar data alone can be difficult because close-range ballistic missiles and surface-to-air missiles may have overlapping ranges and flight characteristics.
"Depending on their launch angles and flight altitudes, their trajectories can also vary, making it difficult to distinguish between the two based on radar data alone," the official said.
The official, however, cautioned that it remains unclear whether continuously deployed Aegis destroyers would have enabled the military to immediately identify Wednesday's launches.
Military sees no surveillance gap, but intelligence concerns remain
The JCS maintains that suspending continuous Aegis deployments has not created a gap in South Korea's missile surveillance posture.
According to the JCS, ground-based radar systems can detect missiles heading toward South Korean territory and track much of the flight of missiles launched toward the East Sea.
Any limitations in tracking can also be supplemented through the real-time missile warning data-sharing mechanism among South Korea, the United States and Japan, as well as intelligence cooperation with Washington and Tokyo, it said.
However, some officials contend that the ability to detect and track missiles threatening South Korean territory should be distinguished from the ability to gather detailed intelligence on North Korean missiles and assess their capabilities.
A ranking military official explained that while ground-based radars offer stable operations and precise tracking, maritime radar systems have the advantage of mobility, allowing them to adjust their positions to improve surveillance coverage.
"Because ground-based radars operate from fixed locations, the Earth's curvature and other factors can limit their ability to track missiles during the later stages of flight as they move farther away," the official said.
"Maritime surveillance assets, on the other hand, can adjust their positions, potentially allowing them to collect additional flight data."
The official also said that these differences do not necessarily translate into diminished missile defense capabilities, as South Korea can still obtain the information needed to respond to missiles threatening its territory without tracking their entire flight over the East Sea.
By contrast, some military personnel directly involved in analyzing missile data have raised concerns about the implications of the suspension for collecting detailed intelligence on North Korean weapons.
A military official assigned to a land-based unit responsible for analyzing Aegis radar data said the suspension had made it more difficult to consistently obtain maritime surveillance data needed to assess North Korean missile characteristics.
"It is true that the absence of continuously deployed Aegis destroyers in the East Sea has imposed certain limitations on analyzing the detailed characteristics of North Korean missiles," the official said.
"We need to continue accumulating data on their ranges, flight trajectories and other characteristics to prepare for future North Korean missile threats."
Intelligence gains come with operational costs
The debate ultimately centers on how the military should balance the intelligence benefits of continuous Aegis deployments against the financial and personnel resources required to sustain them.
Although Aegis destroyers provide advanced maritime surveillance capabilities, keeping them at sea for extended periods entails substantial operating costs and places considerable demands on their crews.
The senior military official who explained the differences between ground-based and maritime radar systems also emphasized the need to consider the operational burden of prolonged deployments.
"Keeping Aegis destroyers continuously deployed offers the advantage of gathering additional intelligence on North Korean missiles, but it also entails substantial operating costs and personnel demands," the official said. "Ultimately, we need to weigh the benefits of collecting additional intelligence against the resources required to do so."
flylikekite@heraldcorp.com
