Lt. Andrew Corbett and Capt. Jared Sunsdahl brief the Chief of Staff of the Army Gen. George W. Casey Jr. about their unit's training exercise at the National Training Center at Fort Irwin, Calif., on Jan. 22, 2011. The mission of the National Training Center is to provide realistic, joint and combined arms training in multi-national venues across the full spectrum of conflict set in a contemporary operating environment to assist commanders and soldiers by presenting current problem sets.