ROK, SF train to defend the base Published Feb. 2, 2023 By Airman 1st Class Aaron Edwards 51st Fighter Wing Public Affairs OSAN AIR BASE, Republic of Korea -- U.S. Air Force Senior Airman Luis Huitron, 51st Security Forces Squadron Defender, plays the role of opposing forces (OPFOR) during a night-time base defense training scenario at Osan Air Base, Republic of Korea, Feb. 1, 2023. OPFOR members simulate enemy movements and attacks providing a realistic threat environment for 51st SFS Defenders to train in. (U.S. Air Force photo by Airman 1st Class Aaron Edwards)