U.S. Air Force Airman 1st Class Eric Knierim, Air Force

U.S. Air Force Airman 1st Class Eric Knierim, Air Force Space Command Defender Challenge competitor, competes during the Weapons Challenge at Joint Base San Antonio-Camp Bullis, Texas, Sept. 11, 2018. Fourteen Security Forces teams from U.S. Air Force major commands, United Kingdom and Germany tested their skills in realistic weapons scenarios, simulated dismounted operations and grueling combat endurance events as part of the 2018 Air Force Defender Challenge.