Aegis Ballistic Missile Defense System

The Aegis Ballistic Missile Defense System (Aegis BMD or ABMD), also known as Sea-Based Midcourse, is a Missile Defense Agency program under the United States Department of Defense. It helps protect against short and intermediate-range ballistic missiles. This program is part of the United States national missile defense and the European NATO missile defense system.

Aegis BMD builds on the Aegis Combat System used on warships. It is designed to stop ballistic missiles during their middle flight, after the rocket has stopped burning but before they re-enter the atmosphere. Ships with Aegis BMD can use Standard Missile 3, Standard Missile 2, and Standard Missile 6 to intercept these threats.

As of 2025^[update], there are two Aegis Ashore sites—one in Romania since 2016 and one in Poland since 2024. Each site has 24 SM-3 missiles.

In 2008, Aegis BMD was used in a test to destroy a satellite called USA-193, as part of Operation Burnt Frost.

History and technical development

Origins

The idea for the Aegis ballistic missile defense system started in the mid-1980s. It was part of President Ronald Reagan’s Strategic Defense Initiative. At first, the plan was to use space-based systems, but because of technology problems, it changed to a system on ships called the Lightweight Exo-Atmospheric Projectile (LEAP). Testing of the LEAP happened as part of the Army LEAP program.

Program history and development

In the late 1990s, the U.S. Navy took over testing LEAP. This phase was called the Aegis LEAP Intercept (ALI) program. It aimed to successfully stop missiles two out of five times. On June 13, 2002, the second successful ALI test happened during the FM-3 flight test. Success with Aegis BMD may have led President George W. Bush to plan an emergency missile defense by late 2004.

After the ALI program, Aegis BMD started being made. The first Block I production SM-3 missile was delivered in October 2004, and the Aegis 3.0 update came in 2005.

President Obama gave the system new importance in September 2009. He decided to stop plans for a missile defense site in Poland and instead use missile defense systems on U.S. Navy ships. In 2009, several U.S. Navy ships were equipped with SM-3 missiles for this purpose, working together with Patriot systems already in use. Ships from Japan and Australia also got weapons and technology to help them join in.

Today’s Aegis BMD system includes the SM-3 Block-1a missile and other improvements. Future plans include Launch on Remote capability, upgraded SM-3 technology, and an improved Aegis Weapon System. In 2012, Aegis Ballistic Missile Defense merged with Aegis Open Architecture to combine benefits from both. The Launch on Remote capability uses off-board sensors, like the Space Tracking and Surveillance System, to guide SM-3 launches.

As of 2022, the Aegis BMD system has versions 4.x, 5.x, and 6.x. These newer versions have better processors, software, and upgraded SM-3 missiles. BMD capable ships can upgrade from older versions to newer ones. Version 6.x uses the AN/SPY-6 radar on Flight III and Flight IIA destroyers.

The US Army Integrated Air and Missile Defense Battle Command System (IBCS) program will connect MIM-104 Patriot, NASAMS, AN/TPY-2, and F-35 Lightning II radars with Aegis radars to create a network of land, sea, and air sensors. This helps land-based Patriot and THAAD launchers defend against ballistic missiles.

SM-3, SM-2 Block IV, SM-6 and GPI interceptors

The Aegis BMD uses the RIM-161 Standard Missile 3 to intercept ballistic missiles above the atmosphere during their middle flight. The missile is launched from warships’ Mk 41 Vertical Launching System and gets updates from the ship during flight. Its kinetic warhead destroys the enemy missile by crashing into it. The SM-3 Block IA version will be updated to Blocks IB, IIA, and IIB to counter future threats.

The RIM-156 Standard Extended Range Block IV (SM-2ER Block IV) can intercept ballistic missiles inside the atmosphere near the end of their flight. It carries a warhead that bursts to break apart the enemy missile. The SM-2ER Block IV was developed into the RIM-174 Standard ERAM (Standard Missile 6), which adds an active radar homing system. The SM-6 can defend against aircraft and cruise missiles, as well as help with ballistic missile defense. It works together with the SM-2 series.

In early 2018, the Navy approved plans to create a Dual Thrust Rocket Motor for the SM-6, making a new version called the SM-6 Block IB.

In March 2018, tests began to see if the SM-3 Block IIA missile could work against very large ballistic missiles. By November 2020, an SM-3 Block IIA successfully hit such a target during a test.

Glide Phase Interceptor (GPI) will defend against hypersonic weapons. GPI will work with a modified Baseline 9 Aegis Weapon System.

In 2024, the Patriot PAC-3 was tested successfully with the Aegis system.

Aegis Ashore

Starting in 2014, a land-based version called Aegis Ashore was developed. The first site to become operational was Deveselu, Romania in 2016. It uses equipment normally found on Navy ships, placed in land facilities. This includes SPY-1 radars and a group of Standard Missile-3s. Plans called for two sites: one in Romania at Deveselu, opened in May 2015, and another in Redzikowo, Poland, which opened in summer 2024. Both sites will receive the latest Aegis BMD software and SM-3 missiles. Some radar facilities may also be placed in Turkey later.

On May 21, 2014, the U.S. Department of Defense announced that a test launch of a Standard Missile from the Aegis Ashore test site was successful. During the test, a simulated ballistic missile target was detected, tracked, and destroyed by the Aegis Weapon System. The test happened at around 7:35 p.m. Hawaii Standard Time on May 20.

In December 2017, Japan approved plans to buy two Aegis Ashore systems with AN/SPY-7(V)1 radars to improve its defense against North Korea. The sites would be in Akita Prefecture and Yamaguchi Prefecture.

In June 2020, Japan stopped work on these systems because of extra costs to make sure residential buildings would not be hit by missile launch boosters. Later that month, Japan’s National Security Council said the plan was cancelled. Lockheed Martin said changing the system for sea use would be very expensive.

In July 2020, the head of the United States Indo-Pacific Command suggested building an Aegis Ashore system in Guam by 2026 to protect U.S. military bases there and to provide long-range attack ability against areas controlled by China.

Developers and Contractors

Important companies and experts working on the system include Boeing Defense, Space & Security, Alliant Techsystems (ATK), Honeywell, Engility, Naval Surface Warfare Center, SPAWAR Systems Center, Johns Hopkins University Applied Physics Laboratory, and the Massachusetts Institute of Technology Lincoln Laboratory.

Deployment

Aegis Ashore

The United States, Romania, and Poland have placed land-based missile defense systems called Aegis BMD. A test site was built in Hawaii in the 2000s. A site in Romania has been working since 2016, and a site in Poland started in the summer of 2024. Each site holds 24 special missiles. Japan planned to build two similar sites with advanced radar, but those plans were stopped in 2020. Possible future sites include a base in Guam.

U.S. Navy Aegis BMD vessels

By October 2017, five Ticonderoga-class cruisers and 28 Arleigh Burke-class destroyers in the U.S. Navy were equipped for missile defense. Seventeen of these ships were in the Pacific Fleet, and sixteen were in the Atlantic Fleet.

Japanese Aegis BMD vessels

The Japanese Maritime Self-Defense Force has fitted four Kongo-class destroyers with missile defense tools. In 2022, Japan announced plans to build two very large new warships for this purpose.

Warships from the United States, Japan, and South Korea practiced missile defense together in the Sea of Japan.

In November 2022, two Japanese warships successfully tested their missile defense systems by hitting targets outside Earth's atmosphere. These tests were done at a U.S. facility in Hawaii with help from the U.S. Navy.

Joint BMD patrols

Warships from the United States, Japan, and South Korea practiced missile defense together in the Sea of Japan.

Political debate

Tom Laliberty of Raytheon said that President Barack Obama should change from a land-based missile defense system to a sea-based one. He said this would make it easier to work with other countries. The U.S. Defense Department also said this sea-based system would be one part of a bigger defense plan that could include land-based facilities.

A Navy group led by retired Vice Adm. Phillip Balisle said that since the late 1990s, trying to save money led to fewer crew members and less training and maintenance. This caused problems with readiness. Even after planning to have fewer Aegis warships, the U.S. Navy still did not have enough for the next 30 years.

International reaction

Some countries have different ideas about this missile defense system. The Russian government has said it might cause a new arms race and that the reasons for making it are not true. In 2012, Dmitry Rogozin, a Russian leader, said Russia would act strongly if any American ships with this system came near their coast.

Other capabilities

Main article: USA 193 § Destruction

In 2008, the Aegis missile defense system destroyed a satellite called USA-193. This was done because there was a worry that dangerous material from the satellite could spread when it fell back to Earth. A ship named USS Lake Erie used a special missile to hit the satellite from far away. This test showed that the system could protect against threats from space.

Target for simulating endo-atmospheric flight of DF-21 ASBM

A report from 2014 said there was no test target to copy the Chinese DF-21 missile. This missile could threaten ships in the Pacific Ocean. The U.S. Navy was meant to make such a target, but they did not have money for it.

In December 2016, the Missile Defense Agency tested a new system. They successfully intercepted a missile target that copied the DF-21. This test was important to see how well the defense system could work against such threats. Later plans included testing the SM-6 missile against even faster and more advanced missile targets.

Flight tests to date

The Aegis system has been tested many times. As of April 2024, it has stopped 45 missiles in 54 test tries.

Gallery

• FM-6 Mission Logo

• FM-8 Mission Logo

• SM-3 interceptor launch during FTM-21

• Launch of SM-3 interceptor during FTM-18

• FTM-14 Mission Logo

• SM-3 Block IIA launch from the Aegis Ashore in Hawaii