The United States is in the midst of replacing its 60‑year‑old Minuteman III intercontinental ballistic missile with a new system called Sentinel, part of a multibillion‑dollar effort to modernize the land‑based leg of the nuclear triad.
At FE Warren Air Force Base in Wyoming, where hundreds of missiles sit in underground silos, roughly 400 Minuteman III weapons are kept in a ready posture officials describe as active deterrence. Sentinel is being developed to replace those aging missiles and the infrastructure that supports them.
Defense leaders overseeing the program say Sentinel will be larger, faster, have longer range, carry more payload, and be more reliable than the Minuteman III. They also emphasize enhanced safety and security features and redesigned procedures for complex missile handling tasks intended to reduce risk to crews and make maintenance easier. The program’s stated goal is to send a clear deterrent message to potential adversaries — effectively, “not today” — underscoring that deterrence requires capabilities kept ready and credible.
Building Sentinel requires new silos and extensive infrastructure work across multiple missile fields. Costs have climbed well above early estimates: the program is reported to be about 80% over initial projected costs, with a current price tag approaching $141 billion, and schedules have slipped beyond original timelines. Critics argue the expense is hard to justify for a weapon meant never to be used; military officials counter that the absence of hostile action is evidence the deterrent is working.
Journalists were allowed access to decommissioned Minuteman III silos and parts of an operational missile field. The Minuteman III stands about 60 feet tall and is housed in deep underground launch tubes. Sentinel silo designs reflect lessons learned from decades of operations — for example, new door systems and access features that let personnel walk through rather than descend ladders, improving safety and maintainability.
U.S. officials point to the expanding and modernizing nuclear forces of China, Russia, and North Korea as drivers of the modernization effort. Military leaders say Sentinel will strengthen deterrence and reassure the American public that the nation retains a credible, modern nuclear force.
Minuteman III missiles remain in service during the transition; officials plan to phase Sentinel in over time with an anticipated full rollout in the coming years and hopes to complete fielding by roughly 2040. Until then, leaders stress the nation maintains an active, ready posture to protect national security and deter aggression.
Ian Lee, CBS News, Cheyenne, Wyoming.