Popular Mechanics devotes their latest cover story to the science of ground-based interceptors. PM writes:

America’s missile shield is designed to destroy incoming ballistic warheads with interceptors. President-elect Obama’s leading contenders for the job as Secretary of Defense have this week sent signals that the next administration would continue the Missile Defense Agency program, and Obama expressed support for it during his campaign. To learn more about missile defense, PM visited an Alaskan Army base where soldiers keep defensive missiles locked and loaded in case a rogue nation makes its move. But will the system work?

Also from the story:

When an interceptor escapes the Earth’s atmosphere, its booster stacks fall away, leaving a tiny spacecraft to finish the suicide mission. This 152-pound, 55-in.-long kill vehicle hurtles through space, using lateral thrusters to steer toward a blunt-force collision with the enemy warhead. “You’ve probably heard it said that we’re trying to hit a bullet with a bullet,” says Col. George Bond, who coordinates Missile Defense Agency (MDA) operations in the Alaska region. “But this is really a brilliant bullet, backed by some of the most powerful radars in the world and a very sophisticated communication system.”