U.S. Air Force Senior Airman Curtis Mower, advanced atmosphere research equipment technician assigned to the 21st Surveillance Squadron, Det. 1, shows a particulate collection paper to Foreign Liaison Officers with Air Forces Southern during a WC-135 Constant Phoenix tour, Feb. 13, 2025 at Davis-Monthan AFB, Arizona. The WC-135, which traveled from Offutt AFB, Nebraska, plays a critical role in nuclear treaty monitoring by collecting airborne effluents and particulates. (U.S. Air Force Photo by Tech. Sgt. Rachel Maxwell)