Aegis Ballistic Missile Defense System

The Aegis Ballistic Missile System (BMDS) is an integrated, advance radar and missile defense system employed by the United States Armed Forces and operated by the US Navy. The systems had its roots in the mid 1960s, when advances in anti-shipping missile platforms began to emerge as the most serious threat facing the world’s most powerful navy. In order to counter the threat these new system might present, the Navy issue a requirement seeking to implement an Advance Surface Missile System (ASMS). As the system began to develop, the Navy changed its designation to that of AEGIS. Such was the sophistication of the AEGIS missile system that the Navy needed to develop a new platform for its implementation. In 1977, the Navy issued an order to develop such platform in the form of a new cruiser.

The first AEGIS-carrying platform was based around the hull of a Spruance Class destroyer. Original designated as a guided missile destroyer, the newly refitted DDG47 was re-organized into a guided missile cruiser. The lead boat of this class was the USS Ticonderoga (CG47). She was commissioned in January 1983 as part of President Ronald Reagan’s massive military build-up of the early 1980s. The game changed when the USS Bunker Hill (CG52) came online, its commissioning ushered a new era in surface weapon platforms. The ‘Hill was the first US ship to deploy a fully operational Vertical Launching System (VLS) designed to counter any airborne threat. As more AEGIS-carrying ships were launched, the system evolved from a purely theater-based system to a larger defensive mechanism capable of supporting large expanse of, not only sea, but land areas. It is this system that is currently the backbone of the United States BMDS platform.

Today, the US deploys three AEGIS capable cruisers and seven destroyers. All fitted with the vaunted SM-3 missile system. The SM-3 is the current incarnation of the SM-2 block IV system. The SM-3 used the same booster and dual thrust rocket system as the SM-2 for the first and second rocket stages. It also used basically the same steering control package and missile guidance system for trans-atmospheric operation. To support the new exo-atmospheric interception profile, the SM-3 used a new third rocket stage for additional thrust. The SM-3 employs a dual-pulse rocket system for exo-atmospheric operation and a Lightweight Exo-atmospheric Projectile with a Kinetic Warhead for the missile’s interception phase. The interception missile received its data from sensors in space and others elements in the BMDS network. The complete system is designed to be autonomous after its launch. The SM-3 can detect, track and engage any ballistic missile threat in its assigned area of operation. The SM-3 Kinetic Warhead does not posses a high explosive fuse, instead, the warhead relies on its kinetic energy released during the missile’s impact with its designated target. The complete energy release is estimated to be above 125 mega joules.

One of the missile system’s backbones is its advance computer soft and hardware integrated system. Raytheon software architecture is design in such way that the overall capability of the system is expanding at the same rate its projected targets threats are perceived to do.

The AEGIS BDM serves the US Armed Forces as its most forward deployed sensors extending the military’s overall battlefield vision. It also provides commanders with a forward tracking and targeting platform for the defense of the United States, Alaska and Hawaii. As the system continues to grow, the integration of the AEGIS with the overall BDM capability of the US Armed Forces will continue. As of today, the AEGIS missile system had provided twelve successful interceptions out of fourteen attempts. These attempts were performed against short-to-medium rage ballistic missiles utilizing a unitary or separating warhead. It’s expected that by the end of the winter of 2008, all 18 ships of the AEGIS class would be fitted with the most advance computer architecture available. The system next evolutionary step will be taken on 2009 and 2010, when its overall capability will be upgraded once more in order to cover a difference defense spectrum, the target’s thermal phase. This upgrade will also provide the SM-3 with a mid-course discrimination tracking, guiding and engagement mechanism that would allow this theater program to engage long range ballistic missiles.

As the AEGIS operates as integrated part of the BMDS platform, its overall capability upgrade will provide the system to coordinate short, medium and even long range missile threats engagements in both, thermal and mid-course stages.

– Raul Colon

More information:
wikipedia: Aegis Ballistic Missile Defense System
AEGIS Combat System
RIM-161 SM-3

Early Development of the United States
Defensive Missile System

As the tactical integration of the continental defenses in the United States in the later stages of World War II evolved, the airplane emerged as the main offensive weapon platform. It had demonstrated that its strategic advantage was un-rivalled at the time. The airplane, especially the bomber, was capable of delivering a heavy bomb payload to far and away locations with devastating effects. This concept was proven over the skies of Spain during that country’s civil war and then over the first two years of World War II. But the action that really made the bomber a weapon of fear was the bombing of Dresden, a major German city, in the later part of the war. The city’s destruction in just one day is widely recognized as the starting point for the development of the strategic annihilation of a city-wide target. As these developments were taking place overseas, the United States began to develop and deploy Interceptor Commands Units all around their coastal areas in late 1941. These units were a combination of two major assets that were to be re-arranged in order to provide a more reliable anti-aircraft system. The first, were the attachment of units of Army Air Forces to Interceptor Command and their deployment near major coastal cities in America. Also, on March 1942, the United States Army constituted the Army Anti-aircraft Command (AA). The newly created command would have control over all Costal Artillery Anti-aircraft Army Units as well as that of the Army’s Interceptor Commands. During the next months, the United States Army developed more advanced anti-aircraft weapon systems. At this time, rockets were staring to appear as accepted weapon systems. Radar, developed in Britain before the war, was rapidly becoming a serious method of detecting and tracking incoming targets. When the war ended in Japan on August 1945, the United States had over 331 active AAs battalions world-wide, with around 246,000 troops at their disposal.

On June 1945, Bell Labs, acting on a request from the Army, commenced the development the first integrated defensive missile system. The Army’s first surface-to-air missile system program was based on an internal Army memo suggesting that the United States must not waste any more time in the development, and ultimately, deployment of an advanced radio-controlled anti-aircraft rocket system that could protect major cities in America against bombing from the air. The new program was code-named Project Nike, after the winged goddess in the Greek mythology. Three months later, with the surrender of Imperial Japan, the U.S. Army started its massive de-mobilization. Most of the active AA units in Europe and the Far East were de-activated and shipped home along with their equipment, the same holds true for the AA battalions in Continental America. The majority of them were de-activated within weeks of the armistice. But the situation would change dramatically in three years. By 1948, the Cold War had broken out in Europe – countries on the eastern side of the Iron Curtain were engulfed by the Soviet Union, and a new age of terror had arrived. America began a prompt process of re-arming and re-organizing its coastal defenses and the U.S. Army re-started its missile development programs that had been shutdown after the war. At the beginning it was anticipated by high ranking officials in the newly created United States Air Force, that high flying interceptor fighters would be the main layer of defense against massive Soviet bomber formations and first generation Inter Continental Ballistic Missiles (ICBM) coming inbound from Soviet mainland bases. U.S. Air Force Strategic bombers as well as the Navy carrier-based attack planes would also participate in the defense of the continent, but it was clear early on, that a new mechanism for dealing with the bomber and, more importantly, with the offensive ballistic missile, was needed. A missile defense system that could replace the outmoded conventional Anti-Aircraft-Artillery guns was imperative to the defense of America. The three services, Navy, Army and the Air Force, revamped their respective missile development programs with the idea of fielding a continent-wide defense missile platform as quickly as possible. In the end, the Navy dropped out of the running, but the Air Force and the Army would fight for the next two decades over control of the missile systems and its funding. A fight that would make a possible deployment of a workable defense missile system a long and tedious process. The main responsibility for the defense of the United States against bomber attacks was assumed by the Air Force in the early 1950s. The Air Force went on to develop the Defense in Depth Strategy that would form the backbone of the U.S. Cold War continental defenses. The new strategy called for the use of high-frequency early warning radar stations along with ‘ready for take-off’ interceptor fighters and long-range anti-aircraft missiles positioned around the perimeter of the U.S. If this defense system was breached by a Soviet force, the U.S. Army would activate its own batteries of anti-aircraft missile systems located around key U.S. industrial and military sites.

In the mid 1960s, the United Stated Air Force was ready to deploy its first advance surface-to-air missile defense system, the Bomarc. The Bomarc was to have a 440 mile range of operation, but constant problems with their guided system limited the deployment of the system from nation-wide, integrated system to a more regional basis. On the other hand, the U.S. Army had fielded its own missile defense system since 1953, the Nike. The initially deployed surface-to-air Nike system used the Nike-Ajax liquid fueled missile with an operational range of thirty miles as it’s main interceptor asset. By the late 1958, there were over two hundred Nike missile batteries in the U.S., primarily defending nuclear research facilities and depots. On December of 1958, the Army began the process of supplanting its Nike-Ajax missile with the more advance Nike-Hercules. The Hercules was a leap forward in the development of a surface-to-air missile. It was propelled by solid-fuel which gave the missile an operational range in excess of seventy five miles. The Hercules was also the first interceptor missile with a nuclear warhead capability. About one hundred Nike sites were upgraded with the Hercules. Of these facilities, around fifty were redeployed to defend the Air Force’s Strategic Air Command bomber bases. The Air Command was the United States primary source for massive nuclear retaliation after a Soviet attack. The key component of the Nike system was an advanced early-warning radar. The U.S. Defense Department was committed from the beginning to building a series of interlocking radar stations that would allow the Army to monitor the perimeter and selected interior parts of the North American continent. The goal of the system was to provide the Air Force and Army with up to five hours of warning to respond in case of a Soviet bomber attack. The U.S. Air Force took the lead in the design, development and deployment of radar systems. The first significant anti-aircraft radar platform was the LASH-Up system. It was designed by the Air Force to cover America’s costal centers and major nuclear production facilities. In 1949, LASH-Up radar stations numbered just seven, but by the end of 1951, the system grew to fifty stations. The LASH-Up system was eventually replaced by the PERMANENT system, which was to number seventy-four radar locations by mid 1952. The U.S. early warning radar system was supplemented by the thirty four stations of the PINETREE LINE system located across the vast Canadian territory, which in theory could provide the Air Force with two additional hours of warning in a case of a surprise attack.

In the summer of 1957, the U.S. Department of Defense approved the production of its more ambitious early detection radar system, the Distant Early Warning (DEW) radar line and the Semi-Automatic Ground Environment (SAGE) air defense control system. The DEW consisted of a series of radar stations fifty miles part, stretching along the northern boundary of the North American continent, several miles north of the Artic Circle. In 1962, the system was upgraded to include an imaginary line from Midway Island to Scotland. The DEW radar line was the outmost line of early warning and it was assisted by the Mid-Canadian Line, the PINETREE Line, the PERMANENT radar system and the Gap Filler Radar System. By the mid 1960s, the U.S. Navy had joined the club with its ship and air-borne radar picket units. With all of these layers of protection, America was still susceptible to one weapon platform, the intercontinental ballistic missile. The SAGE system incorporated the latest in computer technology to support the estimated fifty Air Force Combat Direction Centers it was schedule to defend. The Combat Direction Center was the predecessor of the North American Aerospace Defense Command, NORAD. Its main function was to coordinate all aspects – radar, sensors, the interceptor aircraft squadrons and the anti-aircraft missile batteries – of the continental air defense system. SAGE became partial operational in 1958 and was fully deployable in early 1961. Each of the massive 275 ton SAGE tracking and targeting computers were housed in four-story windowless buildings. Because of their immense size and the fact that they needed to be located above ground, they were extremely vulnerable to any air attack. Still, SAGE was the first truly integrated tactical command system in the United States. It linked the Air Force’s Air Defense, Tactical Air and Strategic Command with the Army Air Defense Command and ARADCOM’s Nike missile system. This capability gave NORAD the necessary resources to detect and track and inbound aircraft coming to the North American continent.

– Raul Colon

More information:
wikipedia: Bomarc Missile
The Pinetree Line
SAGE Air Defense