Secretary Visit Defense Secretary James N. Mattis participated in the U.S. Northern Command/North American Aerospace Defense Command change-of-command ceremony at Peterson Air Force Base, Colo., May 24, 2018. Air Force Gen. Lori J. Robinson relinquished Northcom/NORAD command to Air Force Gen. Terrence O’Shaughnessy. Mattis is pictured here speaking with Robinson, left, and other defense leaders at Peterson Air Force Base, Colo., Nov. 16, 2017. DoD photo by Army Sgt. Amber I. Smith SHARE IMAGE: Download Image: Full Size (1.51 MB) Tags: Travels , JIm Mattis, Sailors, SecDef, Navy , AIR FORCE, Airmen Photo By: Sgt. Amber I. Smith VIRIN: 171116-D-SV709-0078.JPG Photo Gallery