DUTY AND SERVICE U.S. Air Force Academy cadets listen to Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, give the commencement address at their graduation at Falcon Stadium in Colorado Springs, Colo., May 26, 2010. Mullen's message to the 1,001 newly commissioned second lieutenants focused on duty and service to the country. SHARE: Download: Full Size (0.05 MB) Credit: VIRIN: 299230-O-YES25-500.jpg Photo Gallery