U.S. and Allied Ballistic Missile Defenses in the Asia-Pacific Region

The Aegis system is deployed on 17 U.S. Navy destroyers and cruisers in the region that conduct ballistic missile tracking, targeting, and engagement capability. These Aegis BMD ships can engage short-(SRBMs), medium- (MRBMs), and intermediate-range ballistic missiles (IRBMs) in either the midcourse or terminal phase of flight. They can also contributed to the defense of the U.S. homeland by detecting and tracking of intercontinental ballistic missiles (ICBMs) and sending this data to Ground-Based Interceptors (GBIs) based in Alaska and California to engage.

Program Overview/Elements:

Aegis provides defenses against regional ballistic missile threats and can also contribute to homeland defense through continuous long-range surveillance and tracking of ICBMs.
All deployed Aegis BMD-capable ships are equipped with either SM-3 Block IA (first-generation) or Block IB (second-generation) missile interceptors for engaging missiles in the midcourse phase—that is, while it is in space.
In addition, Aegis ships can use SM-2 and SM-6 missiles to engage SRBM targets inside the atmosphere in the terminal phase using explosive warheads rather than the kinetic hit-to-kill vehicles used by the SM-3.
Aegis BMD ships carry the AN/SPY-1 radar, a phased-array S-band radar system, for detection and tracking of ballistic missiles.
As of December 2018, the system has a record of 40 successful intercepts in 49 attempts against ballistic missile targets.

Status:

As of 2016, there are 33 Aegis BMD-capable U.S. navy ships deployed around the world, with 17 of those assigned to the Pacific Fleet. Two additional Aegis ships are being repaired as of early 2018.
Of these 17 Pacific Fleet BMD ships: 8 are homeported in San Diego, CA; four in Pearl Harbor, HI; and five in Yokosuka, Japan.

Current Developments:

In its FY 2019 budget request, MDA projected having 57 Aegis BMD-capable ships and 560 SM-3 interceptors—including 48 Block IIA interceptors—deployed by FY 2023. MDA also projected a total deployment of 41 Aegis BMD-capable ships by the end of 2019.
Along with Japan, the Pentagon is developing the SM-3 Block IIA missile, a 21-inch diameter variant of the SM-3 with an extended range and higher velocity than the current SM-3 interceptors.
- Set for deployment beginning in 2018 on U.S. Navy and Japanese Maritime Self-Defense Force Aegis capable ships.
- The first intercept test of the new SM-3 IIA interceptor occurred in February 2017 and was successful. However, the second and third intercept tests of the missile in June 2017 and January 2018 failed to destroy their targets. The third and fourth tests in October and December of 2018 were successful, and notably the December 2018 test was the first time the interceptor intercepted an IRBM-class target and "engage on remote" using a forward-based sensor.
The AN/SPY-6 radar (also known as AMDR) is being developed as a replacement to the AN/SPY-1. Once complete, the AN/SPY-6 will be able to detect thirty times as many targets that are “half the size, at twice the distance” of the current AN/SPY-1.

Hawaii

Home to U.S. Pacific Command Headquarters, Hawaii is defended by the Ground-based Midcourse Defense (GMD) system designed to counter strategic threats. It also hosts the Sea-Based X-Band Radar and is slated to host a new long-range discrimination radar system by 2023.

Sea-Based X-Band Radar (SBX)

Program Overview/Key Elements:

A massive phased-array X-band radar housed inside a 120-foot diameter radome and supported on a self-propelled, floating platform which primarily acts as the principle midcourse sensor for the strategic BMD system.
Its radar has a 2,500-mile range and is meant to serve in an advanced position to track incoming missiles, discriminate between warheads and decoys or countermeasures, and relay this data to interceptor missiles. Many have cast doubt on SBX’s ability to fulfill this role, primarily because of its extraordinarily narrow 25-degree field of view, compared to 90-120 degrees in other air defense radars.
SBX could also support regional BMD systems to protect troops in forward-deployed positions.

Status:

SBX spends most of its time on “limited test support status” in port in Pearl Harbor, Hawaii. It operates at sea in support of BMDS tests or when the security environment dictates that it may be needed.

Current Developments:

In a February 2018 press briefing on the agency’s FY 2019 budget request, MDA spokesman Gary Pennett announced that MDA had extended the SBX’s ability to stay at sea to “closer to 300 days.”

Homeland Defense Radar-Hawaii (HDR-H)—(planned)

Overview/Key Elements:

A planned land-based, long-range discrimination radar that MDA plans to field in 2023. HDR-H would improve the ability of the GMD homeland defense system to protect Hawaii from ICBMs.

Status:

PACOM Commander Adm. Harry Harris told Congress in February 2018 that the HDR-H is in the final phase of the siting process.
MDA spokesman Gary Pennett said that same month that a second, similar radar will be deployed to an as-yet undetermined location in the Pacific (HDR-P) in 2024 to add to the sensor architecture.
For fiscal year 2019, the Missile Defense Agency requested $62 million for HDR-H, and an additional $34 million for HDR-P.

Guam

Guam is the closest U.S. territory to the Korean peninsula and Andersen Air Base and Naval Base Guam are among several possible targets for DPRK intermediate-range ballistic missiles (IRBMs). With 7,000 U.S. servicemen stationed in Guam and 163,000 U.S.-citizen residents living on the island, the U.S. military sought to enhance BMD coverage of the island already provided by Aegis BMD ships by deploying a THAAD battery.

Terminal High Altitude Area Defense (THAAD)

Overview/Key Elements:

A THAAD battery consisting of 6 launchers with 8 interceptors per launcher was deployed to Andersen Air Base, Guam in 2013 along with its associated AN/TPY-2 radar and fire control stations.
Adm. Harry Harris, commander of U.S. Pacific Command, reiterated in February 2018 testimony to Congress the Pentagon’s view that THAAD is needed on Guam to protect against North Korean intermediate-range ballistic missiles.
THAAD is designed to intercept ballistic missiles in their terminal phase as a ballistic missile is reentering the atmosphere on the way to its target, meaning it would have a chance to attempt an intercept at a later stage than an Aegis ship and thus provide an additional layer of BMD coverage.

South Korea

BMD coverage of South Korea is centered on engaging missiles in the terminal phase of flight. U.S. and South Korean forces operate several U.S.-made BMD platforms on the peninsula to defend against short- and medium-range North Korean missiles, including a U.S.-operated THAAD battery and several U.S.- and South Korean-operated Patriot batteries on land. South Korea is developing several indigenous short-range BMD systems, under its Korean Air and Missile Defense (KAMD) system scheduled to be deployed by the early 2020s. U.S. and South Korean Aegis BMD ships also patrol South Korean waters.

U.S.-operated systems:

Terminal High Altitude Area Defense (THAAD)

Overview/Key Elements:

The U.S. Army deployed a THAAD battery, consisting of six launchers with eight interceptors per launcher and associated radar and fire control equipment in April 2017 to defend against North Korean MRBMs and SRBMs.
THAAD’s position in Seongju is too far south to protect Seoul or U.S. forces stationed on the border and at Camp Humphreys. Designed to intercept missiles within a 124-mile range, the THAAD battery is positioned to potentially defend US troops landing and disembarking from the port of Busan in the southeast in the event that the United States deploys additional forces to the peninsula. It could also defend major urban areas in the southern part of the peninsula, amounting to coverage for roughly 10 million South Koreans.

Patriot Advanced Capability-3 (PAC-3)

Overview/Key Elements:

The United States is believed to operate 8 PAC-3 batteries in classified locations around South Korea, likely deployed around key U.S. military bases.
PAC-3 system can share tracking and targeting data as well as engage short-range ballistic missiles at a lower altitude than THAAD, allowing for layered but overlapping terminal-phase coverage.

Status:

In August 2017, the U.S. Army announced that it had completed upgrading its Patriot systems at Osan Air Base in Seoul to PAC-3.

South Korean-operated systems:

Aegis ships

Overview/Key Elements:

South Korea operates 3 Sejong-Daewang (Sejong the Great, or KDX-III)-class destroyers that are equipped with a version of the Aegis system, Baseline 7, that is not BMD-capable. South Korea’s ships can communicate with and relay targeting data between U.S. Aegis BMD ships, but cannot currently track or engage ballistic missiles.
While the Aegis system deployed on South Korean ships can link data with U.S. ships, it cannot directly link data to Japanese Aegis BMD ships because they do not share a common encryption system.
According to a 2009 U.S. Defense Security Cooperation Agency announcement, South Korea already has SM-2 missiles in its inventory with terminal-phase BMD potential should it upgrade its Aegis systems from Baseline 7 to Baseline 9.

Current Developments:

The next generation of three KDX-III destroyers, set to enter into service in 2023, 2025, and 2027, will be built with the latest Aegis Baseline 9 software and will be fully capable of BMD detection and tracking. Many analysts have also speculated that these destroyers will be equipped with a version of the SM-3 missile interceptor to give them an engagement capability as well.
Several press reports, citing anonymous South Korean defense officials, have hinted that South Korea is looking to upgrade its three operating KDX-III destroyers with a newer version of Aegis that would give them BMD capability in the near term.

Korean Air and Missile Defense (KAMD)

Overview/Key Elements:

KAMD is a multi-platform, short-range air and missile defense concept that South Korea has been developing since 2006 to enhance its protection against DPRK SRBMs, cruise missiles, and light aircraft.
In April 2014, South Korea announced it was upgrading its 8 existing Patriot Advanced Capability-2 (PAC-2) batteries to PAC-3 by the end of 2018 and would buy PAC-3 missiles by 2020.
South Korea is developing the Cheongung Korean medium-range surface-to-air missile (KM-SAM), intended to intercept DPRK SRBMs and MRBMs at a relatively low altitude, similar to PAC-3.
The Korean long-range surface-to-air missile (KL-SAM), under development until 2020, will reportedly be similar to THAAD, operating in a high-altitude, terminal-phase intercept role against SRBMs and MRBMs.

Status:

South Korean forces operate 8 PAC-2 and PAC-3 batteries around Seoul (exact locations classified), which compose the only layer of defense for the roughly 20 million South Koreans that are not covered by THAAD.
South Korea is reportedly in the final phase of developing the KM-SAM, which Seoul aims to deploy between 2018 and 2019.

Current Developments:

The South Korean Defense Acquisition Program Administration approved a planned PAC-3 Missile Segment Enhancement (PAC-3 MSE) system purchase on Feb. 7, 2018.
The PAC-3 MSE systems will provide an additional layer of terminal-phase defense to the PAC-3 systems, since the MSE system can reportedly engage medium- and short-range ballistic missiles at an altitude of 40 km, twice that of the PAC-3. PAC-3 MSE missiles feature new software that improves its targeting as well as a two-stage rocket booster that extends the range of interceptors to 19 miles.

Japan

Japan has heavily invested in an integrated BMD system and has focused on midcourse defense with the Aegis system. Japan operates four Aegis BMD ships with plans to build four more by the early 2020s. The cabinet in December 2017 approved a plan to build two Aegis Ashore sites by the early 2020s. U.S. Aegis ships and U.S. and Japanese Patriot batteries offer another layer of defense.

U.S.-operated systems:

Aegis BMD Ships

Overview/Key Elements:

The U.S. 7th Fleet, which is based in Japan and operates in East Asia, has six destroyers and one cruiser equipped with Aegis BMD systems that are assigned to BMD operations.
These Aegis ships are equipped with SM-3 Block IA and Block IB interceptors and SPY-1 radars. They can relay or receive data to and from other Aegis ships—including both Japanese and South Korean Aegis ships—and are interoperable with Aegis and land-based systems such that their interceptors can be “launched on remote” using tracking data from off-board sensors.

Status:

There are only five U.S. Aegis BMD ships permanently stationed in Japan. Two additional ships are under repair and likely will return to service in summer 2018.
The Navy does not announce when, where, or which BMD ships patrol in the region, but reportedly half of the Japan-based BMD fleet is at sea at any given time.

Patriot Advanced Capability-3

Overview/Status:

U.S. forces operate PAC-3 systems in Japan at U.S. military bases, most of which are on the island of Okinawa.
The first U.S. PAC-3 systems were originally deployed in 2006. The deployments were located near Kadena Air Base (Kadena Town, Okinawa City, and Chatan Town), as well as near Kadena Ammunition Storage Area (Yomitan Village, Okinawa City, Kadena Town, Onna Village, and Uruma City).
Movements and deployments of U.S.-operated PAC-3 units in Japan are not publicly available.

AN/TPY-2 Radar

Overview/Key Elements:

The U.S. operates 2 AN/TPY-2 mobile radar systems—the same radar used in conjunction with THAAD—in Japan.
Since these TPY-2 radars are not paired with THAAD launchers, they are likely operated in the forward-based mode to detect missile launches in North Korea. The radars then relay data to Aegis BMD ships.
Mobile radars can be quickly moved in response to changing needs.

Status:

In December 2014, the U.S. military deployed the second AN/TPY-2 radar to a Japanese Air Self-Defense Force base near Kyoto.
The other TPY-2 radar is deployed at Shariki JASDF base in northern Japan.

Japanese-operated systems:

Aegis BMD

Overview/Key Elements:

The Japan Maritime Self-Defense Force (JMSDF) deploys four Kongo-class destroyers equipped with Aegis BMD system and SM-3 Block IA interceptors.
Kongo-class destroyers can link data directly to U.S. (but not South Korean) Aegis destroyers and coordinate missile tracking.
Under Japan’s constitution, it can only attempt to shoot down missiles or missile debris headed toward Japanese territory, meaning that while its Aegis ships could help track DPRK IRBMs headed toward Guam, for example, they could not launch interceptors to engage them.

Status:

Japan is modifying two Atago-class destroyers to operate the Aegis system in the near future.
The first Atago-class cruiser was launched on July 30, 2018, the Japanese Ministry of Defense said in a statement. The second is expected to be commissioned in March 2021.

Current Developments:

Japan announced in 2013 that it planned to acquire two more Aegis BMD destroyers, which would enter service in 2020 and 2021 and be equipped with Aegis Baseline 9 and SM-3 Block IIA interceptors, bringing its total fleet of BMD ships to eight.
Japan’s Aegis BMD ships are set to begin receiving the SM-3 Block IIA missile, which Japan co-developed with the United States, as soon as it is deployed on U.S. ships. The U.S. State Department cleared an advanced sale of four Block IIA missiles in January 2018. Japan expects that the extended range and higher velocity of the Block IIA will enhance the overlapping coverage of its BMD systems.

Aegis Ashore—(planned)

Overview/Key Elements:

In December 2017 Prime Minister Shinzo Abe’s Cabinet approved a Defense Ministry plan to purchase two Aegis Ashore systems. Officials confirmed they hope the systems will be operational by 2023.
Armed with SM-3 Block IIA missiles, the two sites will reportedly be able to defend all of Japan against MRBMs and IRBMs and provide overlapping layers of defense with the Aegis BMD fleet. Japanese officials believe this will allow them to reduce the number of JMSDF BMD destroyers deployed.

Status:

Citing Japanese Defense Ministry sources, press reports in September 2017 said that Japan was evaluating sites for placing two Aegis Ashore systems on Japan’s western coast (one in the north, one in the south). Akita and Yamaguchi prefectures are seen as possible sites for the units.
The Aegis Ashore units are estimated to cost at least ¥100 billion ($920 million) each.

PAC-3

Overview/Key Elements:

As of 2015, Japan operates 24 PAC-3 units in 15 military bases, most of them positioned around Tokyo and key locations to act as a final layer of defense beyond Aegis ships.
Being relatively mobile, Japan can and has frequently moved PAC-3 units to shift BMD coverage based on changing threats.
Intended as a point-defense system with an engagement range of just 12 miles, PAC-3 interceptors could also break up missile debris falling over Japan.

Status:

As of 2013, PAC-3 systems were known to be deployed to: Aibano in Shiba Prefecture; Naha in Okinawa Prefecture; Hakusan in Tsu, Mie Prefecture; on the grounds of the Ministry of Defense in Tokyo; on the island of Okinawa
Japan announced in August 2017 that it was deploying four PAC-3 systems to Hiroshima, Kochi, Shimane, and Ehime in southwestern Japan.

Current Developments:

According to press reports in 2016, Japan plans to upgrade its PAC-3 batteries with Missile Segment Enhancement (MSE) missiles by the 2020 Tokyo Olympics.

Early Warning Radar

Overview/Key Elements:

Japan operates a network of 28 ground-based air defense radar stations across the country, and of these 11 are BMD capable, stretching the length of Japan’s west coast and facing North Korea and China.
Includes seven older FPS-3 radars that have been upgraded to FPS-4 to be BMD capable and four more advanced FPS-5 radars.
FPS-5 and upgraded FPS-3 radar sites are linked to Japan’s Aegis BMD destroyers and PAC-3 batteries through the Japanese Aerospace Defense Ground Environment (JADGE).

Status:

FPS-5 radars are stationed at: Ominato, Sado, Shimo-koshiki island, and Yozadake (Okinawa)
FPS-3UG (FPS-4) radars are stationed at: Tobetsu, Kamo, Otakineyama, Wajima, Kyogamisaki, Kasatoriyama, and Sefuriyama

Australia

Australia has invested relatively little in its BMD architecture compared to other U.S. allies in the region given its low threat from missiles and has limited BMD detection and tracking capabilities and no engagement capability. But the communications and satellite terminal bases that Australia has hosted for decades as part of U.S. global signals intelligence-gathering efforts have been expanded to play key early warning and communications roles in the U.S. BMD system, and Australia is rolling out a class of Aegis destroyers that could become BMD-capable and will begin production on a class of Aegis BMD frigates in the next five years. Australia’s Aegis fleet will be integrated with U.S., Japanese, and South Korean Aegis ships and may have some engagement capability against MRBMs and IRBMs.

U.S.-operated BMD systems:

Early Warning Radar/Satellite Stations

Overview/Key Elements:

Joint Defense Base Pine Gap, near Alice Springs in central Australia, is a ground control station for U.S. spy satellites that reportedly plays a role in the U.S. BMD command, control, and communications architecture. It monitors missile testing and tracks missile threats in the Asia-Pacific region.
Reportedly, Pine Gap receiving systems can compute the trajectory of DPRK missile launches and send tracking data to other U.S. BMD systems.

Status:

Hosts six satellite terminals for the Relay Ground Station, which relays data from early warning satellites (the Space Based Infrared System, or SBIRS) to U.S. and Australian command centers.
Another three radomes are speculated to be associated with MDA’s experimental Space Tracking and Surveillance System (STSS) program.

Current Developments:

According to press reports beginning in 2013, the United States and Australia planned to relocate two U.S. advanced radar stations to North West Cape, Western Australia—ostensibly for monitoring satellites in space, according to Australian officials—that could potentially monitor Chinese and DPRK missile launches.

Australian-operated BMD systems:

Jindalee Operational Radar Network (JORN)

Overview/Key Elements:

Jindalee Operational Radar Network (JORN), an over-the-horizon radar system recently constructed in the Australian outback, has the capability to detect missile launches in Asia with its 3000 km range and could potentially be integrated into a multilateral BMD system in the near future as an early warning and tracking capability.

Aegis BMD Ships—(under-development)

Overview/Key Elements:

Australia is building an Aegis fleet that will field three Hobart-class destroyers equipped with Aegis Baseline 8 and SM-2 missiles, capable of countering cruise missiles but not BMD capable.
Australia’s Aegis ships will be networked with U.S., Japanese, and South Korean Aegis ships, allowing them to share data. The Hobart-class destroyers will not be able to directly participate in BMD operations but could be upgraded.

Status:

HMAS Hobart, commissioned in September 2017, and HMAS Brisbane, commissioned in October 2018, are operational Australian Aegis ships, but are not BMD-capable. The final Hobart class ship, NUSHIP Sydney is expected to be delivered to the Royal Australian Navy in March 2020.

Current Developments:

Like the Hobart, the Brisbane and the Sydney also won’t have BMD capability until they are upgraded, although press reports have speculated that Australian Defence Department plans intend to upgrade the Hobart-class destroyers to Aegis Baseline 9 and equip them with SM-6 interceptors, making them capable of tracking ballistic missiles and giving them a limited terminal phase intercept capability against SRBMs and MRBMs.
Malcolm Turnbull announced in October 2017 that Australia’s nine new frigates of the Future Frigate project which will begin construction in 2020 will be fitted with the Aegis system and will be BMD capable.
Most analysts speculate that Australia’s Aegis fleet would be used to defend forward-deployed forces and track threats along with allied Aegis ships, but that Australia is not yet moving toward a homeland defense system.