A mechanism designed to steer a kinetic interceptor toward a ballistic missile target failed during a June 18 test of the Navy's missile defense system causing the interceptor to miss its intended target, a Defense Department official said today. The aim of the test, called Flight Mission-5, was to gauge the guidance, navigation and control of a kinetic warhead carried aboard a Standard Missile-3 using an improved solid divert and attitude control system (SDACS). The SDACS works as a thruster...