Ballistic missile defense

Missile defense is a system, weapon, or technology involved in the detection, tracking, interception, and destruction of attacking missiles. Originally conceived as a defence against nuclear-armed intercontinental ballistic missiles (ICBMs), its application has broadened to include shorter-ranged non-nuclear tactical and theater missiles.

The United States, Russia, China, India, Israel, and France have all developed such air defense systems. In the United States, missile defense was originally the responsibility of the U.S. Army. The U.S. Missile Defense Agency has developed maritime systems and command and control that will eventually be transferred to the Navy and Air Force for operation and sustainment.

Missile defense can be divided into categories based on various characteristics: type/range of missile intercepted, the trajectory phase where the intercept occurs, and whether intercepted inside or outside the Earth's atmosphere:

The types/ranges are strategic, theater and tactical. Each entails unique requirements for intercept, and a defensive system capable of intercepting one missile type frequently cannot intercept others. However, there is sometimes overlap in capability.

Targets long-range ICBMs, which travel at about 7 km/s (15,700 mph). Examples of currently active systems: Russian A-135 system which defends Moscow, and the U.S. Ground-Based Midcourse Defense system that defends the United States from missiles launched from Asia. Geographic range of strategic defense can be regional (Russian system) or national (U.S. system).

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