Missile Defense System Ties Many Elements Together

Integrated ballistic missile defense system. Image courtesy of the Missile Defense Agency   (Click photo for screen-resolution image);high-resolution image available.

The stated mission of the Missile Defense Agency is to field a layered missile defense system that integrates land-, sea-, and air-based missile defenses to protect the U.S. homeland, deployed troops, and America's friends and allies against all types of ballistic missiles in all phases of flight.

Basically, that means the United States is working toward the ability to shoot down short-, medium-, and long-range ballistic missiles in their boost phase; during their mid-course flight, normally outside of the Earth's atmosphere; and as they descend toward their target.

The system will incorporate a global array of sensors and radars, satellite tracking and surveillance; interceptors aboard ships at sea; ground-based interceptor missiles in underground silos; mobile-launch interceptors; and powerful lasers fixed to aircraft. The goal is to have several cracks at shooting down enemy missiles in various stages of flight, as well as to hedge against an accidental ballistic missile launch.

"It's a very daunting challenge, but one that I think the men and women of the Missile Defense Agency, the Army, Navy and Air Force are pulling together and are now achieving," Air Force Lt. Gen. Henry A. (Trey) Obering III, the director of the Missile Defense Agency, told an audience at the 4th Annual U.S. Missile Defense Conference here March 20.

Currently, the United States has a limited missile defense capability. Multiple sensors and radars are positioned around the world to detect and track enemy missiles, but they do not yet offer global coverage. Some Navy Aegis-class ships are equipped with standard missiles capable of intercepting short- and medium-range ballistic missiles. Nine ground-based interceptor missiles are located at Fort Greely, Alaska, and two at Vandenberg Air Force Base, Calif., which offer a limited defense against long-range ballistic missiles. And there are Patriot missiles, which have been successful against tactical ballistic missiles during both Persian Gulf wars.

The ground-based system was demonstrated for the media in a war game at the conference. In the exercise, 10 long-range ballistic missiles were fired from a fictional rogue nation called Midland, located in the Sea of Japan, at Honolulu, Fort Greely, Los Angeles and San Francisco, as well as other U.S. locations. Using simulated computer graphics, the participants tracked inbound missiles and launched interceptors when appropriate.

Operators must determine which inbound missile poses the gravest danger. High population centers and defensive locations are deemed the most valuable assets to protect. In this scenario, Los Angeles and Fort Greely would take precedence over Honolulu and San Francisco.

However, real-world command-and-control personnel operating the system might choose to launch the first interceptor at the inbound missile targeting Honolulu, since it has the shortest distance to impact. Radars and sensors tell operators how much time they have to fire an interceptor at an enemy missile before it has passed the point of no return.

The command and control structure for this chain of events is fairly streamlined, with pre-authorization already given by the president, officials said.

U.S. military officials said that in an ideal world, two interceptors would target each incoming missile just in case the first missed. But since the stockpile is limited, only two interceptors were allocated to defend Los Angeles during the war game. The margin for error, as demonstrated by this war game, could be minuscule.

The real interceptors in Alaska and California can be brought to alert status in an emergency, but are not yet fully operational, officials explained. An additional 11 interceptors are expected to be in place by the end of 2007, and a total of 38 by end of 2009. These anti-ballistic missiles are "hit-to-kill" interceptors that destroy incoming missiles by physically colliding with them. The interceptors are the only anti-ballistic missiles in the U.S. arsenal capable of defending the U.S. homeland against long-range intercontinental ballistic missiles, U.S. military officials said.

Several new missile defense capabilities will be integrated into the system over the coming months and years. One is the "sea-based x-band radar," which has been put to sea and is expected to be fully operational by the end of the year. The war game used this radar's capability.

An airborne laser also is being developed and tested. This system is a chemical oxygen iodine laser fitted to a heavily modified Boeing 747. The laser will destroy a missile during its boost phase by heating the missile's metal skin until it cracks.

A mobile kinetic energy interceptor is being developed to destroy missiles in their boost phase. There are also "multiple-kill vehicles" in the pipeline, which will enable one booster rocket to carry numerous interceptors. In addition, new types of space sensors are being looked at, and the "Terminal High Altitude Area Defense," a defense against tactical ballistic missiles, is moving forward.

"The scope of the missile defense system is especially impressive," Deputy Defense Secretary Gordon England said during the missile defense conference March 20. "It brings together a broad spectrum of sophisticated technology. It integrates information on a massive scale, and it is international in reach."