The U.S. Air Force, Northrop Grumman and industry partner Bechtel recently broke ground on the LGM-35A Sentinel intercontinental ballistic missile launch silo prototype in Promontory, Utah. This prototype is critical for validating the modular, cost-effective construction approach for 450 future silos that will support the modernization of the land-based leg of the nation’s nuclear triad. The data gathered will inform the final design and reduce risks before full-rate production. (U.S. Air Force courtesy photo)