DISTINGUISHED SERVICE Defense Secretary Leon E. Panetta presents Air Force Chief of Staff Gen. Norton A. Schwartz with the Defense Distinguished Service Medal at the Air Force Retirement and Appointment Ceremony, where Air Force Gen. Mark A. Welsh III succeeded Schwartz as the 20th chief of staff on Joint Base Andrews, Md., Aug. 10, 2012. SHARE: Download: Full Size (0.05 MB) Credit: VIRIN: 004670-G-ANE69-561.jpg Photo Gallery