Despite a decade of testing and tens of billions of dollars’€™ worth of research, a major missile defense program in the United States has proven to be anything but successful, a new investigation suggests. Nevertheless, the Missile Defense Agency, or MDA, plans on conducting next week its ninth exercise of that costly system since 2004, and the outcome of the drill is expected to influence whether or not more than a dozen new interceptors are added to the United States’ arsenal.