The US plans to demonstrate by 2008 a new anti-missile weapon. Known as the Kinetic Energy Interceptor, this ground-launched weapon would be able to chase down (or rather, up) a ballistic missile during its launch phase and ram it, preventing the missile from reaching its target. This weapon would be highly mobile and could be rushed to the front lines against nations with missile programs, allowing any missiles they launch to be destroyed. Later, sea-based and air-launched versions of the KEI will be fielded. A second-generation KEI in 2012 will have an advanced kill vehicle able to chase missiles into space and attack them during their mid-course maneuvers. The possibility for a space-based version is being left open as it would violate several treaties.--Stephen V Cole