U.S. Army Spc. Christopher Cameron, assigned to the 263rd Army Air and Missile Defense Command, operates an Avenger missile system during Vigilant Shield 2012 at Naval Air Station Key West, Fla., Nov. 5, 2011. Vigilant Shield is a week-long annual exercise designed to emphasize an integrated Department of Defense and civil response in support of the national strategy of aerospace warning and control, defense support of civil authorities and homeland defense. U.S. Air Force photo by Tech. Sgt. Dennis J. Henry Jr.