More will be deployed in 2006 and 2007. But for operational security reasons the Defense Department will no longer divulge how many interceptors are deployed, only that it is in excess of 10.

More will be deployed in 2006 and 2007.

It will increase our knowledge on how this particular type of radar will track missiles. The goal is faster processing of information. We need missile information very quickly.

The interceptors are part of an integrated system of ground, sea and space-based sensors, ground and sea-based radars and an advanced command and control, battle management and communication system designed to detect and track a hostile ballistic missile, then launch and guide an interceptor to destroy the target warhead before it can reach its intended target in any of our 50 states.

It's difficult hitting something that is traveling at 15,000 miles per hour, especially when trying to avoid decoys and other interference. Many people think that we have always had the capability to shoot down a missile that was aimed at a city or town in the U.S., but it is only very recently that we have developed the technology.

Iran and North Korea are two countries that have been spending a great deal of time and money to develop several different types of advanced ballistic missiles, including a type that could possibly reach the U.S. homeland with a weapon of mass destruction in the near future.

It could be available in the event of an emergency, but until all the training and procedures are completed, it's not ready for 24/7 alert status.

A total of nine planned ground-based intercept tests have taken place since 1999; five have resulted in successful intercepts.