The Missile Defense Agency's effort to accelerate development of a new Ground-based Midcourse Defense kill vehicle -- a more than $2.6 billion project to deliver a reliable ballistic missile defense warhead to protect the United States from North Korean and potential Iranian threats -- suffered a setback when the Redesigned Kill Vehicle did not pass muster with a key design review last year. The RKV program -- a project to design a more reliable, producible, testable and cost-effective exo-atmospheric kill...