U.S. Air Force Staff Sgt. Aaron Kostiuk, 435th Security Forces Squadron ground combat readiness training center instructor, performs a sweep on an airfield during exercise Frozen Defender in Grostenquin, France, Jan. 14, 2020. Frozen Defender tests the squadron’s capabilities in a contested environment under harsh conditions. Kostiuk and his team conducted the sweeps to secure the airfield from potential threats. (U.S. Air Force photo by Staff Sgt. Devin Boyer)