Air Force Chief of Staff Gen. David Goldfein signs the 821st Security Forces Squadron’s Defender wall July 20 during his visit to Thule Air Base, Greenland. The CSAF’s visit to Thule prompted AFIMSC to work with Air Force Space Command and Headquarters Air Force to find a solution for the installation’s small arms sustainment training limitations. (U.S. Air Force photo by Staff Sgt. Alexandra M. Longfellow)