People in Seoul watch a report on a North Korean ICBM test-launch in November 2017.
Chung Sung-Jun/Getty Images
North Korea has launched a record-setting number of missiles this year.
That has led Japan to examine its missile defense, which relies on specially designed warships.
Japan’s leaders are now considering adding two new ships to their ballistic-missile defense fleet.
On November 21, Japan’s Maritime Self-Defense Force announced that its two newest destroyers, JS Maya and JS Haguro, had successfully conducted anti-ballistic missiles tests off the coast of Hawaii.
The announcement means Japan now has eight mission-capable ballistic-missile defense destroyers, and comes amid a record-setting series of missile tests by North Korea, with over 50 missiles launched in the past two months and eight ICBMs since January.
At least one of those missiles, launched on October 3, flew directly over the Japanese mainland — the first to do so in five years.
The launches have forced Japan to examine its unique ballistic-missile defense system, which relies heavily on specially equipped warships to intercept incoming missiles.
Ballistic-missile defense
JS Haguro fires an SM-3 Block IB missile during a live-fire exercise off the coast of Hawaii on November 18.
US Missile Defense Agency/Heather Cavaliere
Japan began developing its current BMD system in 2004. Since then, it has evolved into a multi-tier BMD system involving all three branches of Japan’s Self-Defense Forces.
The Japanese Maritime Self-Defense Force’s Aegis Ballistic Missile Defense System-equipped destroyers are tasked with intercepting ballistic missiles in their mid-course stage, when they’re still outside the earth’s atmosphere.
Japan’s Air Self-Defense Force commands Patriot missile-defense batteries with Patriot Advanced Capability-3 missiles that are designed to intercept ballistic missiles in their terminal stage, after they reenter the atmosphere.
Finally, Japan’s Ground Self-Defense Force commands Type 03 medium-range surface-to-air missile systems meant to intercept any missiles in the medium range of airspace.
The interceptors are linked into a massive network of satellites, radars, ships, and aircraft that monitor the area around Japan for any incoming threats. The data they collect is uploaded to the Japan Aerospace Defense Ground Environment, Japan’s warning and control system.
Within minutes of a threat being detected, JADGE calculates a possible point of impact and orders relevant defense systems to prepare for intercept. JADGE also issues an evacuation order, if needed.
BMD destroyers
Japanese guided-missile destroyer JS Maya in the Philippine Sea in May 2021.
US Navy/MCS3 Quinton A. Lee
The Aegis-equipped BMD ships are the most important part of Japan’s BMD system. Eight are in service: four Kongō-class destroyers (Kongō, Kirishima, Myōkō, and Chokai), two Atago-class destroyers (Atago and Ashigara), and two Maya-class destroyers (Maya and Haguro).
The Maya-class vessels are the newest, commissioned in 2020 and 2021. They are also the first BMD destroyers designed specifically for the BMD role. The others were retrofitted after entering service.
The Mayas have 96 vertical-launch tubes capable of firing a mix of Type 07 anti-submarine rockets, Type 90 or Type 17 anti-ship missiles, and RIM-162 Evolved Sea Sparrow missiles. The most important armament, though, is the interceptors — the SM-3 and SM-6 missiles.
The recent tests involving Maya and Haguro in Hawaii saw Maya successfully intercept a ballistic missile outside the atmosphere with an SM-3 Block IIA missile and Haguro intercept another missile outside the atmosphere with an SM-3 Block IB.
In a third shoot-down, Haguro intercepted a missile that was being tracked by Maya, demonstrating integrated missile-defense capabilities that the JSDF has long sought.
Japanese guided-missile destroyer JS Kongō in the Sea of Japan on April 12.
US Navy/MCS Seaman Aleksandr Freutel
There are advantages to relying on maritime-based platforms for missile defense. Their mobility allows them to cover a larger area and get closer to enemy launch points. It also makes it harder for enemies to target and destroy them.
By launching from open ocean, BMD ships also ensure that no booster debris from SM-3 and SM-6 missiles land in populated areas — a major reason Japan canceled the acquisition of the Aegis Ashore system in 2020.
In September, Japan’s Ministry of Defense announced that Japan would build two new BMD destroyers.
The proposed ships would be 690 feet long, 130 feet wide, and displace some 20,000 tons, making them among the largest ships in the Japanese fleet since World War II. They would be larger than the US’s Zumwalt-class destroyers and slightly smaller than Japan’s Izumo-class carriers, which are being converted to operate F-35B jets.
The new ships’ bigger size would allow the JMSDF to send them on longer deployments, operate them in foul weather, arm them with more missiles, and equip them with the massive SPY-7 radar.
The first ship is planned to be commissioned in 2028 and the second in 2029.
An urgent need
A North Korean Hwasong ICBM, seen in March.
API/Gamma-Rapho via Getty Images
Relying on warships for ballistic-missile defense also has disadvantages, chiefly the cost. The ships need to be large, mobile, loaded with extremely sophisticated software, and have specially trained crews.
They wouldn’t usually venture far from their patrol areas around Japan, but each would need to spend considerable time in port for maintenance or crew training, meaning Japan would need a fairly large number of them to ensure enough were deployed at any given time.
“The issue with sea-based missile-defense systems is if you’re building really big expensive ships that are going to stay in one place, then you might as well save the money and build these really big systems on shore,” Zack Cooper, a senior fellow at the American Enterprise Institute, told Insider.
Soldiers with Patriot missiles at the Defense Ministry in Tokyo in April 2012.
JIJI PRESS/AFP/GettyImages
“You might have to have six ships to keep two on site at any one time, and building six expensive missile-defense ships is probably really not the best way to take up pretty valuable shipyard time,” Cooper added.
The proposed 20,000-ton BMD destroyers are estimated to cost as much as $7.1 billion, a massive price given recent economic woes and fears of an impending global recession.
That may be why the Japanese government has reportedly scaled back the size of the two new planned ships to about that of the Maya-class ships. The decision regarding the ships is likely to be made clear in Japan’s new National Defense Program Guidelines, which are set to be released in mid-December.
Japan’s need for ballistic-missile defense is only growing more urgent, however. So far this year, North Korea has conducted a record number of missile launches, firing IRBMs, ICBMs, SLBMs, and, most worrying for Japan, hypersonic missiles.
People in Tokyo walk past a screen detailing a North Korean missile launch in September 2021.
KAZUHIRO NOGI/AFP via Getty Images
If Japan sticks with sea-based missile defense, it may acquire two more BMD destroyers of an entirely new design or build more Maya-class vessels to save money and time.
Tokyo could also change its mind and adopt Aegis Ashore. Maintenance and training on the land-based system would be less of an issue, and it may end up being cheaper: When Japan canceled the program in 2020, it was expected to cost $4.2 billion over 30 years.
“In the North Korea context, where you basically know exactly where the missiles are being shot from and where they would be aimed toward, it just doesn’t make a whole lot of sense to build a whole bunch of missile-defense destroyers just to keep two on station at any one time,” Cooper said.