Aegis Combat System

The word "Aegis" is a reference that dates back to Greek mythology, with connotations of a protective shield, as the Aegis was the buckler (shield) of Zeus, worn by Athena.

File:Aegis Combat System.png of the Aegis Combat System (Baseline 2-6)]]

The Aegis Combat System (ACS) implements advanced command and control (command and decision, or C&D, in Aegis parlance). It is composed of the Aegis Weapon System (AWS), the fast-reaction component of the Aegis Anti-Aircraft Warfare (AAW) capability, along with the Phalanx Close In Weapon System (CIWS), and the Mark 41 Vertical Launch System.Originally, the first five ships of the United States' Aegis equipped Ticonderoga-class cruisers were outfitted with Mark-26 twin-arm missile launchers; however, the ships with this system have been decommissioned and are no longer in service. Mk 41 VLS is available in different versions that vary in size and weight. There are three lengths: {{convert|209|in|m|abbr=on}} for the self-defense version, {{convert|266|in|m|abbr=on}} for the tactical version, and {{convert|303|in|m|abbr=on}} for the strike version. The empty weight for an 8-cell module is {{convert|26800|lb|kg|abbr=on}} for the self-defense version, {{convert|29800|lb|kg|abbr=on}} for the tactical version, and {{convert|32000|lb|kg|abbr=on}} for the strike version, thus incorporating anti-submarine warfare (ASW) systems and Tomahawk Land Attack Cruise Missiles (TLAM). Shipboard torpedo and naval gunnery systems are also integrated.

AWS, the heart of Aegis, comprises the AN/SPY-1 Radar, MK 99 Fire Control System, Weapon Control System (WCS), the Command and Decision Suite, and Standard Missile family of weapons; these include the basic RIM-66 Standard, the RIM-156 Standard ER extended range missile, and the newer RIM-161 Standard Missile 3 designed to counter ballistic missile threats. A further SM-2 based weapon, the RIM-174 Standard ERAM (Standard Missile 6) was deployed in 2013. Individual ships may not carry all variants. Weapons loads are adjusted to suit assigned mission profile. The Aegis Combat System is controlled by an advanced, automatic detect-and-track, multi-function three-dimensional passive electronically scanned array radar, the AN/SPY-1. Known as "the Shield of the Fleet", the SPY high-powered (6 megawatt) radar is able to perform search, tracking, and missile guidance functions simultaneously with a track capacity of well over 100 targets at more than {{convert|100|nmi|km|-1}}.{{cite encyclopedia | title = Aegis Combat System | encyclopedia = The Warfighter Encyclopedia | publisher = Warfighter Response Center | date = October 8, 2003 | url = https://wrc.navair-rdte.navy.mil/warfighter_enc/weapons/shiplnch/aegis.htm | access-date = August 10, 2006 | archive-url = https://web.archive.org/web/20041105105518/https://wrc.navair-rdte.navy.mil/warfighter_enc/weapons/shiplnch/aegis.htm | archive-date = November 5, 2004 }}. However, the AN/SPY-1 Radar is mounted lower than the AN/SPS-49 radar system and so has a reduced radar horizon.{{cite web|url=http://www.fas.org/man/dod-101/sys/ship/weaps/an-spy-1.htm|title=AN/SPY-1 Radar|access-date=29 January 2016}}

The Aegis system communicates with the Standard missiles through a radio frequency (RF) uplink using the AN/SPY-1 radar for mid-course update missile guidance during engagements, but still requires the AN/SPG-62 fire-control radar for terminal guidance. This means that with proper scheduling of intercepts, a large number of targets can be engaged simultaneously.

The computer-based command-and-decision (C&D) element is the core of the Aegis Combat System and came from the Naval Tactical Data System (NTDS) threat evaluation and weapons assignment (TEWA) function.[https://ethw.org/First-Hand:Legacy_of_NTDS_-_Chapter_9_of_the_Story_of_the_Naval_Tactical_Data_System#Building_Aegis First-Hand:Legacy of NTDS - Chapter 9 of the Story of the Naval Tactical Data System] Section 4.3 Building Aegis. Engineering and Technology History Wiki This interface makes the ACS capable of simultaneous operation against almost all kinds of threats.

In December 2019, Lockheed Martin released a promotional video heralding the 50th anniversary of the Aegis combat system.{{cite web |title=20191205_Lockheed_AEGIS_50th_Anniversary_3D_ME_FINAL |url=https://vimeo.com/377587148/64f428add4 |website=Vimeo.com |publisher=Green Buzz Agency |access-date=10 December 2019 |archive-url=https://web.archive.org/web/20191210152251/https://vimeo.com/377587148/64f428add4 |archive-date=10 December 2019 |date=5 December 2019 |url-status=live}}

File:USS Norton Sound (AVM-1) underway at sea, circa in 1980.jpg

Aegis was initially developed by the Missile and Surface Radar Division of RCA, which was later acquired by General Electric. The division responsible for the Aegis systems became Government Electronic Systems. This, and other GE Aerospace businesses, were sold to Martin Marietta in 1992.Lenorovitz, Jeffrey. "GE Aerospace to merge into Martin Marietta" Aviation Week & Space Technology. November 30, 1992. Accessed on July 19, 2007 This became part of Lockheed Martin in 1995.

By the late 1950s, the U.S. Navy replaced guns with guided missiles on its ships. These were sufficient weapons but by the late 1960s, the U.S. Navy recognized that reaction time, firepower, and operational availability in all environments did not match the anti-ship missile threat.{{Cite book |title=Hearings on H.R. 6566, ERDA Authorization Legislation (National Security Programs) for Fiscal Year 1978 |year=1977 |page=145}} The new threat of Soviet anti-ship missiles exposed a weakness in contemporary naval radar. The requirements of both tracking and targeting these missiles was limited by the number of radars on each ship, which was typically 2–4. In 1958 the navy started the Typhon Combat System, a prophetic program culminating in the futuristic but unreliable AN/SPG-59 phased array radar, which was never made viable and was cancelled in 1963 to be replaced by the Advanced Surface Missile System (ASMS).{{Cite web |url=http://www.harpoonhq.com/waypoint/articles/Article_044.pdf |title=Archived copy |access-date=2012-07-11 |archive-date=2017-11-18 |archive-url=https://web.archive.org/web/20171118103754/http://www.harpoonhq.com/waypoint/articles/Article_044.pdf }}

As a result, the U.S. Navy decided to develop a program to defend ships from anti-ship missile threats. An Advanced Surface Missile System (ASMS) was promulgated and an engineering development program was initiated in 1964 to meet the requirements.{{cite web|url=http://usmilitary.about.com/od/navyweapons/a/aegis.htm|title=Aegis Cruisers|work=About.com Careers|access-date=29 January 2016|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304193341/http://usmilitary.about.com/od/navyweapons/a/aegis.htm}} ASMS was renamed "Aegis" in December 1969 after the aegis, the shield of the Greek god Zeus. The name was suggested by Captain L. J. Stecher, a former Tartar Weapon System manager, after an internal U.S. Navy contest to name the ASMS program was initiated. Captain Stecher also submitted a possible acronym of Advanced Electronic Guided Interceptor System although this definition was never used.Lockheed Martin. "Aegis Heritage". Presentation. November 20, 2002. The main manufacturer of the Aegis Combat System, Lockheed Martin, makes no mention of the name Aegis being an acronym, nor does the U.S. Navy.

In 1970, then-Captain Wayne Meyer was named Manager Aegis Weapons System. Under his leadership the first systems were successfully deployed on various U.S. Navy vessels.

The first Engineering Development Model (EDM-1) was installed in a test ship, {{USS|Norton Sound|AVM-1|6}}, in 1973.{{cite web|url=http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=200&ct=2|title=The US Navy -- Fact File: Aegis Weapon System|author=Dan Petty|access-date=29 January 2016|archive-date=4 February 2016|archive-url=https://web.archive.org/web/20160204184720/http://www.navy.mil/navydata/fact_display.asp?cid=2100&tid=200&ct=2}} During this time frame, the Navy envisioned installing the Aegis Combat System on both a nuclear-powered "strike cruiser" (or CSGN) and a conventionally-powered destroyer (originally designated DDG 47). The CSGN was to be a new, 17,200 ton cruiser design based on the earlier {{sclass|California|cruiser|5}} and {{sclass|Virginia|cruiser|0}} cruisers. The Aegis destroyer design would be based on the gas turbine powered {{sclass|Spruance|destroyer|4}}. When the CSGN was cancelled, the Navy proposed a modified Virginia-class design (CGN 42) with a new superstructure designed for the Aegis Combat System and with a displacement of 12,100 tons. As compared to the CSGN, this design was not as survivable and had reduced command and control facilities for an embarked flag officer. Ultimately this design was also cancelled during the Carter Administration due to its increased cost compared to the non-nuclear DDG 47. With the cancellation of the CGN 42, the DDG 47 Aegis destroyer was redesignated as CG 47, a guided missile cruiser.

The first cruiser of this class was {{USS|Ticonderoga|CG-47|6}}, which used two twin-armed Mark-26 missile launchers, fore and aft. The commissioning of the sixth ship of the class, {{USS|Bunker Hill|CG-52|6}} opened a new era in surface warfare as the first Aegis ship outfitted with the Martin Marietta Mark-41 Vertical Launching System (VLS), allowing a wider missile selection, more firepower, and survivability. The improved AN/SPY-1B radar went to sea in {{USS|Princeton|CG-59|6}}, ushering in another advance in Aegis capabilities. {{USS|Chosin|CG-65|6}} introduced the AN/UYK-43/44 computers, which provide increased processing capabilities.

During 1980, the {{sclass|Arleigh Burke|destroyer|2}} was designed using an improved sea-keeping hull form, reduced infrared and radar cross-sections, and upgrades to the Aegis Combat System. The first ship of the class, {{USS|Arleigh Burke}}, was commissioned during 1991. A notional design that incorporated the capabilities of a VLS-capable Ticonderoga with a hull and superstructure designed to Arleigh Burke standards, called "Cruiser Baseline", was studied although not built.

Flight II of the Arleigh Burke class, introduced in 1992, incorporated improvements to the SPY-1 radar, and to the Standard missile, active electronic countermeasures, and communications. Flight IIA, introduced in 2000, added a helicopter hangar with one anti-submarine helicopter and one armed attack helicopter. The Aegis program has also projected reducing the cost of each Flight IIA ship by at least $30 million.

Recent Aegis Combat System ships come with active electronically scanned array radars which use solid-state gallium nitride emitters. These include Canadian Surface Combatant (CSC) and Spanish {{sclass2|F110|frigate|1}}s, which use the AN/SPY-7 radar from Lockheed-Martin, and {{sclass|Constellation|frigate|1}}s which use AN/SPY-6 radar from Raytheon. AN/SPY-6 radar will also be installed in Flight III and Flight IIA Arleigh Burke-class destroyers, giving them Ballistic Missile Defense capability currently deployed on Flight I and Flight II ships.

{{anchor|Aegis Open Architecture}}

The Aegis Ballistic Missile Defense System (BMD) program by the U.S. Missile Defense Agency enables the Aegis system to act in a sea-based ballistic missile defense function, to counter short- and medium-range ballistic missiles of the variety typically employed by a number of potential opponent states. The program is part of the United States national missile defense strategy and NATO European missile defense system.

BMD capabilities allow vessels equipped with Mk 41 Vertical Launching System (VLS) to intercept ballistic missiles in post-boost phase and prior to reentry, using the RIM-161 Standard Missile 3 (SM-3) mid-course interceptors{{Cite web |title=Standard Missile-3 (SM-3) |url=https://missilethreat.csis.org/defsys/sm-3/ |access-date=2022-08-30 |website=Missile Threat |language=en-US}} and the RIM-156 Standard Missile 2 Extended Range Block IV (SM-2ER Block IV){{Cite web |title=Standard Missile-2 Block IV |url=https://missilethreat.csis.org/defsys/standard-missile-2-block-iv/ |access-date=2022-08-31 |website=Missile Threat |language=en-US}} terminal-phase interceptors.{{Cite web |title=Aegis Ballistic Missile Defense |url=https://missilethreat.csis.org/system/aegis/ |access-date=2022-11-30 |website=Missile Threat |language=en-US}} The SM-2ER Block IV can engage the ballistic missiles within the atmosphere (i.e. endoatmospheric intercept) in the terminal phase of a missile's trajectory with a blast fragmentation warhead. The Standard Missile 3 is a development of the SM2-ER Block IV, capable of exo-atmospheric intercept (i.e. above the atmosphere) during the midcourse phase; its kinetic warhead (KW) is designed to destroy a ballistic missile's warhead by colliding with it. RIM-174 Standard ERAM (Standard Missile 6) extended range active missile is a further development of the SM-2ER Block IV, which adds a booster and an active radar homing seeker.[http://www.naval-technology.com/projects/aegis-ballistic-missile-defence-bmd-us/ Aegis Ballistic Missile Defence (BMD) System, United States of America] SM-6 can be used for either air defense or ballistic missile defense, providing extended range and increased firepower; it is not intended to replace the SM-2 series of missiles.Sydney J. Freedberg, Jr., [http://breakingdefense.com/2014/08/non-standard-navy-sm-6-kills-cruise-missiles-deep-inland/ "Non-Standard: Navy SM-6 Kills Cruise Missiles Deep Inland"] – Breakingdefense.com, 19 August 2014 The SM-6 Block IB includes a larger 21-inch rocket motor that sits on top of the 21-inch booster.{{Cite web|url=https://news.usni.org/2018/12/18/39724|title = Report to Congress on Aegis Ballistic Missile Defense|date = December 18, 2018}}

To enable Ballistic Missile Defense capabilities, signal processing for the SPY-1 radar was upgraded using commercial off-the-shelf components and open architecture standards.{{cite web|url=http://www.lockheedmartin.com/us/news/press-releases/2010/september/091610_aegis_bmd.html|title=Lockheed Martin Successfully Completes Formal Testing of Second-Generation Aegis Ballistic Missile Defense Capability|website=www.lockheedmartin.com|date=2010-09-16|url-status=usurped|archive-url=https://web.archive.org/web/20130127000428/http://www.lockheedmartin.com/us/news/press-releases/2010/september/091610_aegis_bmd.html|archive-date=2013-01-27}} The Multi-Mission Signal Processor (MMSP) provides Anti-Air Warfare (AAW) and Ballistic Missile Defense (BMD) capability for the first 28 ships (DDGs 51–78) of the U.S. Navy's Arleigh Burke-class destroyers. This capability is also incorporated in {{USS|John Finn|DDG-113}} and following new construction, as well as Aegis Ashore. MMSP modifies transmitters of the SPY-1D radar to enable dual-beam operation for reduced frame times and better reaction time, and provides stability for all waveforms, allowing the radar system to detect, track, and support engagements of a broader range of threats. MMSP improves performance in littoral, ducted clutter, electronic attack (EA), and chaff environments and provides greater commonality in computer programs and equipment.FY 2013 Presidential Budget (PB): Navy, February 2012. Exhibit R-2, Research, Development, Test, and Evaluation (RDT&E) Budget Item Justification: Program Element (PE) 0604501N: Advanced Above Water Sensors, Page 2 of 37. [https://web.archive.org/web/20140201211211/http://www.dtic.mil/descriptivesum/Y2013/Navy/stamped/0604501N_5_PB_2013.pdf]. Accessed on 04 April 2013{{cite web|url=http://www.lockheedmartin.com/us/news/press-releases/2010/april/aegis-live-tracking-041210.html|title=pr_mission_aegis-live-tracking-041210 · Lockheed Martin|website=www.lockheedmartin.com}}

As of January 2025, the U.S., Japan, and South Korea{{cite web |last1=Vavasseur |first1=Xavier |title=South Korea’s HHI Cut Steel of New KDX III Batch II Destroyer for ROK Navy |url=https://www.navalnews.com/naval-news/2021/03/south-koreas-hhi-cut-steel-on-new-kdx-iii-batch-ii-destroyer-for-rok-navy/ |date=March 2021}} are the only countries to purchase or deploy the Aegis BMD on their military ships.{{cite web|url=http://www.mda.mil/system/aegis_bmd.html |title=Aegis Ballistic Missile Defense |author= |date=8 January 2014 |website=Missile Defense Agency |publisher=US Dept. of Defense |access-date=30 January 2014 |archive-url=https://web.archive.org/web/20140125154343/http://www.mda.mil/system/aegis_bmd.html |archive-date=25 January 2014 }}{{cite web|url=http://www.mda.mil/system/aegis_foreign_mil_sales.html |title=Aegis Ballistic Missile Defense - Foreign Military Sales |author= |date=2 January 2014 |website=Missile Defense Agency |publisher=US Dept. of Defense |access-date=30 January 2014 |archive-url=https://web.archive.org/web/20131013190230/http://www.mda.mil/system/aegis_foreign_mil_sales.html |archive-date=13 October 2013 }}

Flight III of Arleigh Burke-class destroyers starting with {{USS|Jack H. Lucas}} are equipped with AN/SPY-6 AESA radar from Raytheon, which is 30 times more sensitive and thus can handle 30 times more targets comparing to the SPY-1D radar, providing increased air and missile defense capabilities.{{cite web |url=https://www.raytheonmissilesanddefense.com/capabilities/products/spy6-radars |title=U.S. Navy's SPY-6 Family of Radars |date=12 July 2020 |website=www.raytheonmissilesanddefense.com |publisher=Raytheon |access-date=12 July 2020}} Flight IIA ships will also be upgraded to SPY-6 in the future, giving them Aegis BMD capabilities.Justin Katz [https://breakingdefense.com/2022/01/raytheon-to-start-back-fitting-destroyers-with-spy-6-radar/ Raytheon to start backfitting destroyers with SPY-6 radar]. Breaking Defense (11 Jan 2022)

Aegis Ashore is a land-based version of Aegis BMD which includes the AN/SPY-1 radar and command systems, and Mk 41 VLS equipped SM-3 and SM-6 missiles. Test installation exists at the Pacific Missile Range Facility in Hawaii. A site in Deveselu, Romania is operational since 2016, and a site near Redzikowo, Poland will become operational in 2022. Japan intended to deploy two systems with an AN/SPY-7 AESA radar by 2021, but cancelled these plans in 2020. Possible deployments of Aegis Ashore include U.S. naval base at Guam.{{Cite web|url=https://crsreports.congress.gov/product/details?prodcode=RL33745|title=Navy Aegis Ballistic Missile Defense (BMD) Program: Background and Issues for Congress (RL33745)|publisher=Congressional Research Service|date=2022-04-01|access-date=2022-05-08|archive-url=https://web.archive.org/web/20220401000000/https://crsreports.congress.gov/product/details?prodcode=RL33745|archive-date=2022-04-01|url-status=live}} [https://sgp.fas.org/crs/weapons/RL33745.pdf Alt URL]

U.S. Army Integrated Air and Missile Defense Battle Command System (IBCS) program aims to integrate Aegis BMD and its AN/SPY-1 and AN/SPY-6 radars with MIM-104 Patriot (AN/MPQ-65A and GhostEye), NASAMS (GhostEye MR), AN/TPY-2 (THAAD and GMD), and F-35 Lightning II (AN/APG-81) radars to form a plug and fight network of land, sea, and air-based sensors to help detect and track ballistic missile threats and select Patriot and THAAD surface-to-air launchers that are best positioned for a successful intercept.

In March 2025, the USS Pinckney participated in Flight Test Other-40 (FTX-40), codenamed Stellar Banshee, in which a virtualized SM-6 Block IAU interceptor was tested against a live multi-stage MRBM test target that utilized a new and previously untested type of hypersonic warhead, designated HTV-1.{{Cite web |last=Eyer |first=Kevin |date=2025-04-05 |title=The Illusion of BMD Testing in Ships {{!}} RealClearDefense |url=https://www.realcleardefense.com/articles/2025/04/05/the_illusion_of_bmd_testing_in_ships_1102182.html |access-date=2025-04-09 |website=www.realcleardefense.com |language=en}} The threat missile was air-launched by parachute drop from a C-17 Globemaster III transport, and was successfully detected and tracked by Pickney, though no actual physical interceptor missile was fired. The test validated a variety of systems, including modern hypersonic missile tracking satellites, the Block IAU version of SM-6, and the ability of the Aegis Weapon System to track hypersonic targets, and a new type of hypersonic test target.{{Cite web |last=Satam |first=Parth |date=2025-03-27 |title=MDA, U.S. Navy Track Hypersonic Weapon with Aegis System in Ballistic Missile Defense Test |url=https://theaviationist.com/2025/03/27/mda-us-navy-stellar-banshee-bmd-test/ |access-date=2025-04-09 |website=The Aviationist |language=en-US}} The Missile Defense Agency subsequently announced that a future live intercept of an MRBM with HTV-1 would be designated as Flight Test Aegis Weapon System-43 (FTM-43).

{{main|Destroyer Squadron 60|European Phased Adaptive Approach}}

On 5 October 2011, U.S. Secretary of Defense Leon Panetta announced that the United States Navy will station four Aegis Ballistic Missile Defense System warships at Naval Station Rota, Spain, to strengthen its presence in the Mediterranean Sea and bolster the ballistic missile defense (BMD) of NATO as part of the European Phased Adaptive Approach (EPAA) missile defense program. On 16 February 2012, it was reported that the Arleigh Burke-class destroyers Donald Cook and Ross would be relocated to Rota during Fiscal Year 2014, followed by Porter and Carney in fiscal year 2015.{{Cite web |title= Navy Names Forward Deployed Ships to Rota, Spain |url= http://www.navy.mil/submit/display.asp?story_id=65393 |work= NNS120216-15 |publisher= U.S. Department of Defense |date= 16 February 2012 |access-date= 11 August 2013 |archive-date= 12 October 2014 |archive-url= https://web.archive.org/web/20141012100428/http://www.navy.mil/submit/display.asp?story_id=65393 }} On 9 May 2013, Commander Destroyer Squadron 60 was formally designated to perform type-command administrative oversight for the four BMD-capable destroyers based at Rota, Spain.{{Cite web |title= ESTABLISHMENT OF COMMANDER, DESTROYER SQUADRON SIX ZERO |url= http://doni.daps.dla.mil/Directives/05000%20General%20Management%20Security%20and%20Safety%20Services/05-400%20Organization%20and%20Functional%20Support%20Services/5400.2244.pdf |work= OPNAVNOTE 5400 Ser DNS-33/13U102244 |publisher= United States Department of the Navy |date= 9 May 2013 |access-date= 11 August 2013 |archive-date= 14 October 2013 |archive-url= https://web.archive.org/web/20131014080705/http://doni.daps.dla.mil/Directives/05000%20General%20Management%20Security%20and%20Safety%20Services/05-400%20Organization%20and%20Functional%20Support%20Services/5400.2244.pdf }}

{{Main|Aegis system equipped vessels (ASEV)}}

File:Conceptual image of JMSDF ballistic missile defense ship, 23 December 2022.png

File:JS Chokai（DDG-176）, USS CHANCELLORSVILLE（CG-62）and ROKS SEJONG DAEWANG（DDG-991）during Japan-U.S.-ROK Trilateral Exercise in the Sea of Japan.jpg

File:JS Haguro（DDG-180）launching SM-3 Block IB. Hawaii, Nov 19, 2022.jpg

The Japanese Maritime Self Defense Force (JMSDF) currently operates four {{sclass|Kongō|destroyer|5}}, two {{sclass|Atago|destroyer|5}}, and two {{sclass|Maya|destroyer|0}} guided-missile destroyers as part of its "Aegis Afloat" program (See table below).

Additionally, on 31 August 2022, The Japan Ministry of Defense announced that JMSDF will operate two "Aegis system equipped ships" (イージス・システム搭載艦 in Japanese) (pictured) to replace the earlier plan of Aegis Ashore installations, commissioning one by the end of fiscal year 2027, and the other by the end of FY2028. The budget for design and other related expenses are to be submitted in the form of "item requests", without specific amounts, and the initial procurement of the lead items are expected to clear legislation by FY2023. Construction is to begin in the following year of FY2024. At 20,000 tons each, both vessels will be the largest surface combatant warships operated by the JMSDF, and according to Popular Mechanics, they will "arguably [be] the largest deployable surface warships in the world.".{{Cite web |date=1 September 2022 |author=Lia Wong |title=Japanese Defense Budget Expansion Includes Two 20,000 Ton Cruisers |url=https://www.overtdefense.com/2022/09/01/japanese-defense-budget-expansion-includes-two-20000-ton-cruisers/ |website=Overt Defense |access-date=7 September 2022}}{{Cite web |date=6 September 2022 |author=Dzirhan Mahadzir |title=Japan to Build Two 20,000-ton Missile Defense Warships, Indian Carrier Commissions |url=https://news.usni.org/2022/09/06/japan-to-build-two-massive-20000-ton-missile-defense-warships-indian-carrier-commissions#more-97081/ |website=USNI News Blog |access-date=7 September 2022}}{{Cite web |date=1 September 2022 |author=Yoshihiro Inaba |title=Japan's New "Aegis Equipped Ships": What We Know So Fars |url=https://www.overtdefense.com/2022/09/01/japanese-defense-budget-expansion-includes-two-20000-ton-cruisers/ |website=NavalNews |access-date=7 September 2022}}{{cite web |url=https://www.popularmechanics.com/military/navy-ships/a41123804/japan-to-build-20-000-ton-warships/ |author=Kyle Mizokami |title=Japan Defense Ministry plans new Aegis destroyers in place of Aegis Ashore |date=12 September 2022 |access-date=13 September 2022 |archive-url=https://web.archive.org/web/20220912200955/https://www.popularmechanics.com/military/navy-ships/a41123804/japan-to-build-20-000-ton-warships/ |website=Popular Mechanics |archive-date=12 September 2022 |url-status=bot: unknown }}

On 6 October 2022, five warships from the United States, Japan, and South Korea held a multilateral ballistic missile defense exercise in the Sea of Japan (pictured) as part of the military response to ongoing North Korean intermediate-range ballistic missile tests over the Japanese home islands.{{cite web |url=https://news.usni.org/2022/10/06/warships-from-u-s-japan-south-korea-ballistic-missile-defense-drills-after-north-korean-missile-shots#more-97916 |title=UPDATED: Warships from U.S., Japan, South Korea Ballistic Missile Defense Drills After North Korean Missile Shots |last=LaGrone |first=Sam |date=October 6, 2022 |website=News Blog |publisher=United States Naval Institute |access-date=October 11, 2022 |quote=}}{{cite web |url=https://www.navalnews.com/naval-news/2022/10/us-navy-jmsdf-and-rok-navy-conduct-bmd-exercise/ |title= US Navy, JMSDF And ROK Navy Conduct BMD Exercise |last=|first=|date=October 6, 2022 |website=NavalNews.com |publisher= |access-date=October 25, 2022 |quote=}}

On 16 November 2022, the guided-missile destroyer {{JS|Maya|DDG-179|2}} fired an SM-3 Block IIA missile, successfully intercepting the target outside the atmosphere in the first launch of the missile from a Japanese warship. On 18 November 2022, the {{JS|Haguro|DDG-180|2}} likewise fired an SM-3 Block IB missile with a successful hit outside the atmosphere (pictured). Both test firings were conducted at the U.S. Pacific Missile Range Facility on Kauai Island, Hawaii, in cooperation with the U.S. Navy and U.S. Missile Defense Agency. This was the first time the two ships conducted SM-3 firings in the same time period, and the tests validated the ballistic missile defense capabilities of Japan's newest {{sclass|Maya|destroyer|1}}s.{{cite web |url=https://news.usni.org/2022/11/21/two-japanese-destroyers-score-in-ballistic-missile-defense-test-off-hawaii#more-99073 |title=Two Japanese Destroyers Score in Ballistic Missile Defense Test off Hawaii |last=Mahadzir |first=Dzirhan |date=November 21, 2022 |website=News Blog |publisher=United States Naval Institute |access-date=November 22, 2022 |quote=}}

On 23 December 2022, the Japanese Ministry of Defense's 2023 budget and program guidance illustrated examples of operation (運用の一例) for the Aegis-equipped naval forces of the Japanese Maritime Self Defense Force (MSDF). The two ASEV warship would be exclusively tasked for dedicated ballistic missile defense (BDM) missions (BMD等) and operate off the Korean peninsula in the Sea of Japan, allowing the other Aegis guided-missile destroyers to meet other contingencies (侵攻阻止) while operating independently to maintain the sea lines of communication (SLOC) open in the East China Sea southwest of the Japanese home islands.{{cite web |url=https://news.usni.org/2022/12/27/japanese-mod-releases-details-on-ballistic-missile-defense-ships#more-99887 |title=Japanese MoD Releases New Details on Ballistic Missile Defense Ships |last=LaGrone |first=Sam |date=December 27, 2022 |website=News Blog |publisher=United States Naval Institute |access-date=January 3, 2023 |quote=}}{{cite web |url=https://www.navalnews.com/naval-news/2022/12/japanese-mod-releases-further-details-of-asev-bmd-destroyers/ |title=Japanese MoD Releases Further Details About Its Future BMD Destroyers |last= |first= |date=December 25, 2022 |website=Naval News |publisher= |access-date=January 3, 2023 |quote=}}{{cite web |url=https://www.thedrive.com/the-war-zone/first-rendering-of-japans-ballistic-missile-defense-ship-concept-released |title=First Rendering Of Japan's Ballistic Missile Defense Ship Concept Released |last=Emma |first=Helfrich |date=December 29, 2022 |website=The Drive |publisher= |access-date=January 3, 2023 |quote=}}{{cite web |url=https://www.mod.go.jp/j/yosan/yosan_gaiyo/2023/yosan_20221223.pdf |title=Defense Programs and Budget of Japan FY Reiwa 5 (2023) Budget Overview |author= |date= December 23, 2022 |website=Budget overview |publisher=Japanese Ministry of Defense |page=15 |access-date=2023-01-09 |quote=Japanese}}

On 22 February 2023, five warships from the United States, Japan, and South Korea held a multilateral ballistic missile defense exercise in the Sea of Japan in response to the launch of a North Korean Hwasong-15 ballistic missile on 18 February 2023, landing in Japan's exclusive economic zone (EEZ) in the Sea of Japan, in an area 125 miles west of the island of Ōshima, which lies {{convert|30|mi|km}} west of the main island of Hokkaido. Two additional ICBMs were subsequently launched on 20 February 2023, with both landing in the Sea of Japan off the east coast of the Korean Peninsula.{{cite web |url=https://news.usni.org/2023/02/22/u-s-japan-south-korea-hold-ballistic-missile-defense-drills-after-north-korean-launches#more-101115 |title=U.S., Japan, South Korea Hold Ballistic Missile Defense Drills after North Korean Launches |last=Mahadzir |first=Dzirhan |date=February 22, 2023 |website=News Blog |publisher=United States Naval Institute |access-date=February 22, 2023 |quote=}} On 19 December 2023, United States, Japan, and South Korea announced the activation of a real-time North Korea missile warning system as well as jointly established a multi-year trilateral exercise plan in response to North Korea's continued ballistic missile launches.{{cite web |url=https://news.usni.org/2023/12/19/u-s-japan-south-korea-establish-north-korean-missile-warning-system-trilateral-exercises |title=U.S., Japan, South Korea Establish North Korean Missile |last=Mahadzir |first=Dzirhan |date=December 19, 2023 |website=News Blog |publisher=United States Naval Institute |access-date=December 22, 2023 }}{{cite web |url=https://www.mod.go.jp/en/article/2023/12/c74496d9056f871004eb2983fb03d626fcc2ff94.html |title=Japan-United States-Republic of Korea Trilateral Ministerial Joint Press Statement |last= |first= |date=December 19, 2023 |website=Press Release |publisher=Japanese Ministry of Defense |access-date=December 24, 2023 }}

In 2010, it was reported that Aegis radar systems on board some individual warships were not being maintained properly. A Navy panel headed by retired Vice Adm. Phillip Balisle issued the "Balisle report," which asserted that over-emphasis on saving money, including cuts in crews and streamlined training and maintenance, led to a drastic decline in readiness, and left Aegis Combat Systems in low state of readiness.[http://www.navytimes.com/news/2010/07/navy_aegis_070510w/ Study says Aegis radar systems on the decline], by Philip Ewing, Navy Times, Wednesday July 7, 2010.

{{Main|Iran Air Flight 655}}

File:CG-47 CIC.png of early Aegis cruisers]]

The Aegis system was involved in a disaster in which {{USS|Vincennes|CG-49|6}} mistakenly shot down Iran Air Flight 655 in 1988 resulting in 290 civilian deaths.

A formal military investigation by the United States Navy concluded that the Aegis system was completely operational and well maintained. The investigation found that if the commanding officer had relied on the complete tactical data displayed by the Aegis system, the engagement might never have occurred. Additionally, psychological effects of the crew subconsciously manipulating the data to accord with a predefined scenario greatly contributed to the false identification. The investigation found that the Aegis Combat System did not contribute to the incident and that the system's recorded target data contributed to the investigation of the incident. The discrepancies between the Aegis data report and what the ship's personnel reported to the commanding officer are as follows:{{Cite web |last=Fogarty |first=William M. |date=July 28, 1988 |title=Formal Investigation into the Circumstances Surrounding the Downing of Iran Air Flight 655 on 3 July 1988 |url=http://www.dod.mil/pubs/foi/International_security_affairs/other/172.pdf |archive-url=https://web.archive.org/web/20060506205901/http://homepage.ntlworld.com/jksonc/docs/ir655-dod-report.html |archive-date=6 May 2006 |access-date=March 31, 2006 |id=93-FOI-0184}}

Other analyses found that ineffective user interface design caused poor integration with the crisis management human processes it was intended to facilitate. The Aegis System software shuffles target tracking numbers as it gathers additional data. When the captain asked for a status of the original target identifier TN4474, the Aegis system had recycled that identifier to a different target which was descending, indicating possible attack posture.{{cite journal |last1=Fisher |first1=Craig |last2=Kingma |first2=Bruce |date=2001 |title=Criticality of data quality as exemplified in two disasters |journal=Information and Management |volume=39 |issue=2 |pages=109–116 |doi=10.1016/S0378-7206(01)00083-0 |citeseerx=10.1.1.15.1047 |s2cid=13015473 }} An article by David Pogue in Scientific American rated it as one of the five "worst digital user-interface debacles of all time."{{cite magazine |last=Pogue |first=David |date=1 April 2016 |title=5 of the Worst User-Interface Disasters |url=https://www.scientificamerican.com/article/pogue-5-of-the-worst-user-interface-disasters/ |magazine=Scientific American |access-date=3 July 2019 |archive-url=https://web.archive.org/web/20160922042401/http://www.scientificamerican.com/article/pogue-5-of-the-worst-user-interface-disasters/ |archive-date=22 September 2016 |url-status=live }}

On December 22, 2024 USS Gettysburg (CG-64) shot down an F/A-18F Super Hornet belonging to Strike Fighter Squadron 11 (VFA-11) and flying off the {{USS|Harry S. Truman|CVN-75}}.{{Cite web |last=Mackintosh |first=Thomas |date=22 December 2024 |title=US pilots shot down over Red Sea in 'friendly fire' |url=https://www.bbc.com/news/articles/cj30zk1jnmno |url-status=live |archive-url=https://web.archive.org/web/20241222140302/https://www.bbc.com/news/articles/cj30zk1jnmno |archive-date=22 December 2024 |access-date=22 December 2024 |website=www.bbc.com |language=en}} USCENTCOM stated that both the pilot and weapon systems officer ejected and were recovered safely shortly after, with only one receiving minor injuries after an initial assessment. The Gettysburg also fired on a second F/A-18 and missed by ~100 feet. The missile missed thanks to the pilot performing evasive maneuvers. Investigation on these incidents are in progress, as of January 2025.{{cite web |last1=Doornbos |first1=Caitlin |title=Second Navy jet nearly brought down by friendly fire in Red Sea |url=https://www.msn.com/en-us/news/world/second-navy-jet-nearly-brought-down-by-friendly-fire-in-red-sea/ar-AA1wrnZ9 |website=MSN |publisher=MSN |access-date=28 December 2024}}{{Cite web |date=22 December 2024 |title=2 U.S. Navy pilots eject safely after fighter jet shot down over Red Sea by likely "friendly fire," officials say - CBS News |url=https://www.cbsnews.com/news/2-navy-fighter-pilots-eject-safely-shot-down-red-sea-friendly-fire-uss-gettysburg/ |url-status=live |archive-url=https://web.archive.org/web/20241222105907/https://www.cbsnews.com/news/2-navy-fighter-pilots-eject-safely-shot-down-red-sea-friendly-fire-uss-gettysburg/ |archive-date=22 December 2024 |access-date=22 December 2024 |website=www.cbsnews.com |language=en}}{{Cite web |last=Gambrell |first=Jon |date=22 December 2024 |title=2 US Navy pilots shot down over Red Sea in apparent 'friendly fire' incident, US military says |url=https://apnews.com/article/mideast-wars-yemen-us-navy-pilots-houthi-95a792daae3b0120186bfc6c66e1b6fe |url-status=live |archive-url=https://web.archive.org/web/20241222085816/https://apnews.com/article/mideast-wars-yemen-us-navy-pilots-houthi-95a792daae3b0120186bfc6c66e1b6fe |archive-date=22 December 2024 |access-date=22 December 2024 |website=www.apnews.com |language=en}}{{Cite web |last=Liebermann |first=Oren |date=22 December 2024 |title=Two US Navy pilots eject safely over Red Sea after fighter jet shot down in apparent friendly fire incident |url=https://edition.cnn.com/2024/12/21/politics/us-fighter-jet-shot-down-red-sea/index.html |url-status=live |archive-url=https://web.archive.org/web/20241222181319/https://edition.cnn.com/2024/12/21/politics/us-fighter-jet-shot-down-red-sea/index.html |archive-date=22 December 2024 |access-date=22 December 2024 |website=CNN |language=en}}

• The Royal Australian Navy commissioned three {{sclass|Hobart|destroyer|1}}s which have Aegis as the core of their combat systems, with the last entering service in 2020. The Australian Government announced that the class of nine {{sclass|Hunter|frigate|1}}s to be built in the next decade will also be Aegis equipped, but with a tactical interface developed by Saab Australia.{{cite web|url=http://www.theaustralian.com.au/national-affairs/missile-defence-for-australias-future-frigates-against-rogue-states/news-story/9a7cdda6bd7c9ffa943a6d67342f0a97|title=Subscribe to The Australian - Newspaper home delivery, website, iPad, iPhone & Android apps|website=www.theaustralian.com.au}} The number of Hunter-class frigates were reduced to 6 following the Australian government's Enhanced Lethality Surface Combatant Fleet program.
• The Royal Canadian Navy has awarded Lockheed Martin Canada building 15 Canadian Surface Combatants. The ships will be equipped with the AN/SPY-7(V)1 solid state radar and the International Aegis Fire Control Loop (IAFCL) is integrated with Canada's combat management system, CMS 330, developed by Lockheed Martin Canada for the Royal Canadian Navy's {{sclass|Halifax|frigate|0}} ships. The program will make Canada the owner of the world's second largest Aegis fleet.
• The Japanese Maritime Self-Defense Force operates eight Aegis ships comprising the four {{sclass|Kongō|destroyer|1}}s that entered service from 1993 and two improved units known as the {{sclass|Atago|destroyer|4}} from 2007. Two further improved units known as the {{sclass|Maya|destroyer|4}} were ordered with the first being commissioned in 2020 and the second in 2021.
• The Royal Norwegian Navy has acquired five Spanish-built {{sclass|Fridtjof Nansen|frigate}}s equipped with the Aegis system, with the first, {{HNoMS|Fridtjof Nansen|F310|6}} entering service in 2006 and the last, {{HNoMS|Thor Heyerdahl|F314|6}}, in 2011. One, {{HNoMS|Helge Ingstad|F313|6}} was sunk after colliding with an oil tanker. After being raised, it was thought that repairing the ship was too costly and so it was decided to scrap the ship.
• Republic of Korea Navy currently operates 4 {{sclass|Sejong the Great|destroyer|1}}s, with the lead ship commissioned in 2008. 2 further vessels have been ordered. The three earlier "Batch I" vessels use Aegis Baseline 7. The three latter "Batch II" vessels use Aegis Baseline 9, which allows the radar to be used for air warfare and BMD at the same time.{{Cite web |last=LaGrone |first=Sam |date=6 September 2016 |title=New South Korean Destroyers to Have Ballistic Missile Defense Capability |url=https://news.usni.org/2016/09/06/new-south-korean-destroyers-ballistic-missile-defense-capability |url-status=live |archive-url=https://web.archive.org/web/20231001024533/https://news.usni.org/2016/09/06/new-south-korean-destroyers-ballistic-missile-defense-capability |archive-date=1 October 2023 |website=U.S. Naval Institute}}
• The Spanish Navy is currently operating five F100 {{sclass|Álvaro de Bazán|frigate|0}} Aegis frigates, and starting it 2024, it will operate the {{sclass2|F110|frigate|1}}{{cite web|url=http://abcblogs.abc.es/tierra-mar-aire/public/post/fragatas-espanolas-diseno-23108.asp/|title=Fragatas F-110: presupuestados por ahora 174 millones en I+D+i y su diseño|date=20 January 2018|publisher=ABC|access-date=24 January 2018}} as well. The F-110 class will incorporate the International Aegis Fire Control Loop (IAFCL) integrated with SCOMBA, the national combat system developed by Navantia.{{Cite web|url=https://www.navalnews.com/event-news/sna-2020/2020/01/sna-2020-four-nations-to-be-protected-with-lockheed-martins-next-generation-spy-7-radar/|title=SNA 2020: Four Nations to Be Protected with Lockheed Martin's Next Generation SPY-7 Radar|date=2020-01-15|website=Naval News|language=en-US|access-date=2020-01-15}}
• The U.S. Navy currently operates the Aegis equipped {{sclass|Ticonderoga|cruiser|1}}s and {{sclass|Arleigh Burke|destroyer|1}}s and has ordered more of the latter. It will reportedly integrate the new Aegis Baseline 10 on its upcoming Constellation-class frigates.{{Cite web|url=https://www.navalnews.com/naval-news/2020/04/fincantieris-fremm-wins-us-navy-ffgx-frigate-competition/|title=Fincantieri's FREMM Wins US Navy FFG(X) Frigate Competition|date=30 April 2020}}

File:Aegis operators.png|Map with Aegis operators in blue

File:DDG173 JDS Kongo.jpg|{{JS|Kongō}}, the first non-U.S. ship equipped with AWS

File:USS Vincennes (CG-49) Aegis large screen displays.jpg|Large screen displays on {{USS|Vincennes|CG-49|6}}, typical of early Aegis platforms, 1988

File:USS Normandy (CG-60) CIC consoles.jpg|Combat Information Center (CIC) consoles aboard {{USS|Normandy|CG-60|6}}, 1997

File:USS John S. McCain (DDG-56) Aegis large screen displays.jpg|Large screen displays on {{USS|John S. McCain|DDG-56|6}}, circa 1997. Destroyers have two displays while cruisers have four.

• Wayne E. Meyer
• {{lwc|Aegis Ballistic Missile Defense System}}
• {{lwc|PAAMS}}
• {{lwc|Typhon Combat System}}

{{Reflist}}

{{Commons}}

• [https://web.archive.org/web/20120524041024/https://www.netc.navy.mil/centers/cscs/ Center For Surface Combat Systems (CSCS)] U.S. Navy Combat Systems Training, Dahlgren, VA.
• [https://web.archive.org/web/20120524041947/https://www.netc.navy.mil/centers/cscs/atrc/ AEGIS Training and Readiness Center (ATRC)] U.S. Navy AEGIS Training, Dahlgren, VA.
• [http://www.fas.org/man/dod-101/sys/ship/weaps/aegis.htm AEGIS Weapon System MK-7] in the FAS Military Analysis Network.
• [http://www.fas.org/man/dod-101/sys/ship/ddg-51.htm DDG-51 ARLEIGH BURKE-class] in the FAS Military Analysis Network.
• {{cite encyclopedia|title=AN/SPY-1 |encyclopedia=The Warfighter Encyclopedia |publisher=Warfighter Response Center |date=October 8, 2003 |url=https://wrc.navair-rdte.navy.mil/warfighter_enc/weapons/SensElec/RADAR/anspy1.htm |access-date=August 10, 2006 |archive-url=https://web.archive.org/web/20041105105825/https://wrc.navair-rdte.navy.mil/warfighter_enc/weapons/SensElec/RADAR/anspy1.htm |archive-date=November 5, 2004 }}.
• {{cite web|title=AEGIS Weapon System MK-7 |publisher=Jane's Information Group |date=April 25, 2001 |url=http://www.janes.com/defence/naval_forces/news/misc/aegis010425.shtml |access-date=August 10, 2006 |archive-url=https://web.archive.org/web/20060701055247/http://www.janes.com/defence/naval_forces/news/misc/aegis010425.shtml |archive-date=July 1, 2006 |url-status=live }}
• {{cite book | chapter = MK 7 AEGIS FIRE CONTROL SYSTEM RADAR | title = FIRE CONTROLMAN, VOLUME 02--FIRE CONTROL RADAR FUNDAMENTALS | publisher = US NAVY | chapter-url = http://www.tpub.com/content/fc/14099/css/14099_38.htm | url = http://www.maritime.org/doc/pdf/fc2.pdf | access-date = August 10, 2006}}

{{US Navy navbox}}

{{Lockheed Martin}}

{{Naval combat systems}}

{{Authority control}}

{{DEFAULTSORT:Aegis Combat System}}

Category:Anti-aircraft warfare

Category:Computer systems of the United States Navy

Category:Anti-ballistic missiles of the United States

Category:Missile defense

Category:Naval radars

Category:Phased array radar