Marine Corps Gen. Joe Dunford, chairman of the Joint Chiefs of Staff, awards Navy Adm. Bill Gortney a Defense Distinguished Service Medal during the change-of-command ceremony for the North American Aerospace Defense Command and U.S. Northern Command at Peterson Air Force Base, Colo., May 13, 2016. Gortney relinquished command of NORAD and Northcom to Air Force Gen. Lori J. Robinson during the event. DoD photo by Navy Petty Officer 2nd Class Dominique A. Pineiro