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AEGIS Weapon System MK-7

Aegis, which means shield, is the Navy’s latest surface combat system. Aegis was designed and developed as a complete system, capable of engaging in simultaneous warfare on several fronts -- air, surface, subsurface, and strike. Anti-Air Warfare elements include the Radar System AN/SPY-1B/D, Command and Decision System, and Weapons Control System.

For more than 40 years, the US Navy has developed systems and tactics to protect itself from air attacks. Since the end of World War II, several generations of anti-ship missiles have emerged as the air threat to the fleet. The first combatant ship sunk by one of these missiles was an Israeli destroyer in October 1967, hit by a Soviet built missile. The threat posed by such weapons was reconfirmed in April 1988 when two Iranian surface combatants fired on US Navy ships and aircraft in the Persian Gulf. The resulting exchange of anti-ship missiles led to the destruction of an Iranian frigate and corvette by US built Harpoon missiles. Modern anti-ship missiles can be launched several hundred miles away. The attacks can be coordinated, combining air, surface and subsurface launches, so that the missiles arrive on target almost simultaneously.

The US Navy's defense against this threat has continued to rely on the strategy of defense in depth. Guns were replaced in the late fifties by the first generation of guided missiles in ships and aircraft. By the late sixties, it was recognized that reaction time, firepower, and operational availability in all environments did not match the threat. As a result, an operational requirement for an Advanced Surface Missile System (ASMS) was promulgated and a comprehensive engineering development program was initiated to meet that requirement. ASMS was re-named AEGIS (after the mythological shield of Zeus) in December 1969.

The complexity of the AEGIS combat system was such that the program demanded special management treatment, which led to the establishment of the AEGIS shipbuilding project at Naval Sea Systems Command (NAVSEA PMS-400) in 1977. The special management treatment combined and structured hull mechanical and electrical systems, combat systems, computer programs, repair parts, personnel maintenance documentation, and tactical operation documentation into one unified organization to create the multi-mission surface combatants that are today's AEGIS cruisers and destroyers.

The AEGIS weapon system is billed as the most capable surface launched missile system the Navy has ever put to sea. Its weapons can be trained on targets at a wide range of altitudes from wave top to directly overhead, and is capable of engaging anti-ship cruise missiles and manned aircraft flying in all speed ranges from subsonic to supersonic. The AEGIS system has been employed in all environmental conditions, having both all-weather capability and the abilitt to operate in chaff and jamming environments.

The surface Navy's AEGIS system provides area defense for the battle group as well as a clear air picture for more effective deployment of F-14 and F/A-18 aircraft. AEGIS enables fighter aircraft to concentrate more on the outer air battle while cruisers and destroyers assume a greater responsibility for battle group area defense. Technological advances in missile and computer battle management systems make it possible for AEGIS equipped ships to join carrier air assets in outer air defense, and the increased accuracy of AEGIS weapon systems results in minimizing the expenditure of assets.

The heart of the AEGIS systems is the AN/SPY-1, a multi-functional phased-array radar capable of automatic detection and tracking of targets. This high-powered (four megawatt) radar is able to perform search, track and missile guidance functions simultaneously with a capability of over 100 targets. The first Engineering Development Model (EDM-1) was installed in the test ship, USS Norton Sound (AVM 1) in 1973.

The system's computer- based command and decision element is the core of the AEGIS combat system. This interface makes the AEGIS combat system capable of simultaneous operation against a multi-mission threat: anti-air, anti-surface and anti-submarine warfare.

There are four ship classes contained within the AEGIS "class" of ships:

After studying several shipboard applications, the decision was made to construct the first AEGIS ships based on the hull and machinery designs of Spruance class destroyers. Originally identified as a guided missile destroyer, DDG-47 class, the class was re-designated a guided missile cruiser. The first ship of the class, USS Ticonderoga (CG 47), was christened by Mrs. Nancy Reagan on Armed Forces Day 1981, and commissioned on January 23, 1983. The commissioning of USS Bunker Hill (CG 52) opened a new era in surface warfare as the first Aegis ship outfitted with the Vertical Launching System (VLS), allowing greater missile selection, firepower and survivability. The improved AN/SPY-1B radar went to sea in USS Princeton (CG 59), ushering in another advance in AEGIS capabilities. USS Chosin (CG 65) introduced the AN/UYK-43/44 computers, which provide increased processing capabilities.

In 1980, the preliminary plans for a smaller ship with AEGIS capabilities were studied. Because of advanced technology in relevant fields, was possible to build an AEGIS system compatible with a smaller ship while maintaining the same capabilities as the previous platform. A smaller ship was designed using an improved sea-keeping hull form, reduced infra-red and radar cross section and upgrades to the AEGIS Combat System. The first ship of the DDG 51 class, Arleigh Burke, was commissioned on the Fourth of July, 1991. The DDG 51 class was named after a living person, the legendary Adm. Arleigh Burke, the most famous destroyerman of World War II. DDG 51s were constructed in flights, allowing technological advances during construction. Flight II, introduced in FY 1992, incorporates improvements to the SPY radar and the Standard missile, active electronic countermeasures and communications. Flight IIA, introduced in fiscal year 1994, 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.

Combat Systems are upgraded in baselines.

On 08 May 1998 a new contract was signed, which with options is valued at $1.97 billion, for the definition, design, development, integration, testing, and delivery of advanced AEGIS Combat System computer program baselines. The work will convert the earliest AEGIS ships — the cruiser class — to more current computer program baseline capabilities, and introducing Navy Area Wide and Theater Wide Tactical Ballistic Missile Defense upgrades to the fleet. This program provides for modifications to the AEGIS Weapon System MK-7 to counter the threat as articulated in ONI System Threat Assessment Report, ONI TA #046-93 dated May 1993 and subsequent updates. The modifications will be introduced into CG 47 Class and DDG 51 Class ships.

The total cost for the AEGIS Weapon System is $42.7 billion. The predominant driver that can be influenced today is operations and support (O&S) at $22.2 billion. Clearly there are opportunities for the production community to make some impact on their O&S costs even if they appear trivial. For example, a one percent reduction in TOC today would buy a brand new ship in 10 years. Some areas that can be targeted by the production community include repair parts, spares, and in-service engineering reductions.

Culture Corner

Aegis is the term used for the armor of Zeus and and Athena, from which the expression "under the aegis of" meaning "under the protection of" is derived. Homer, in the Odyssey and the Illiad, consistently repeats the formulaic "Pallas Athena, daughter of Aegis-bearing Zeus" when mentioning the patron goddess of Athens.
"Athena went among them holding her priceless aegis that knows neither age nor death. From it there waved a hundred tassels of pure gold, all deftly woven, and each one of them worth a hundred oxen. With this she darted furiously everywhere among the hosts of the Achaeans, urging them forward, and putting courage into the heart of each, so that he might fight and do battle without ceasing. Thus war became sweeter in their eyes even than returning home in their ships."
THE ILIAD Book II by Homer translated by Samuel Butler
The aegis, or skin of the goat Amalthea, was in early depictions fastened over the shoulders and breast, and hung over the left arm as a shield-cover [LEFT]. Afterwards it was used solely as a breastplate with the Gorgon's head. Pallas Athena (Minerva) was depicted wearing the aegis with the Gorgon's head on her breast in the statue by Phidias in the Parthenon [RIGHT].

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