LGM-35A Sentinel is the U.S. Air Force’s next-generation intercontinental ballistic missile (ICBM) system, designed to replace the aging LGM-30 Minuteman III fleet. It is part of the modernization of the land-based leg of the U.S. nuclear triad and is expected to remain in service through 2075.
Cost: The program’s total cost has significantly increased, rising from an initial estimate of $95.3 billion to $140.9 billion as of July 2024, following a Nunn-McCurdy breach. The Program Acquisition Unit Cost (PAUC) has increased from $118 million per missile (2020 estimate) to $162 million (as of December 2023), primarily due to rising infrastructure and command/control system costs.
Capabilities: The Sentinel features a three-stage solid-fuel rocket booster, improved accuracy, reliability, and sustainability over the Minuteman III. It is designed to carry a single W87-1 nuclear warhead in a Mk 21A re-entry vehicle, though payload configurations may evolve. The system includes advanced digital engineering, open-architecture design, and enhanced command, control, and communications capabilities.
Deployment Timeline: Initial Operational Capability (IOC) is now projected for the early 2030s, delayed from the original 2029 target. The program is undergoing a major restructuring following a 2024 cost breach. A Milestone B decision (transition to development and production) is expected by the end of 2026, with the first prototype launch planned for 2027.
Infrastructure: The program involves modernizing or replacing 450 missile silos and over 600 facilities across five states (Wyoming, Montana, North Dakota, Nebraska, and Colorado). This includes new silos, launch facilities, and command centers, contributing to cost and schedule challenges.
Program Status: Northrop Grumman is the prime contractor, leading a team of subcontractors including Lockheed Martin, General Dynamics, L3Harris, and others. The Air Force plans to procure 634 operational missiles plus 25 for testing and development.
Strategic Role: The Sentinel is critical to U.S. nuclear deterrence, ensuring a safe, secure, and credible land-based deterrent for decades. The system will maintain the current force level of 400 ICBMs on alert and will be integrated with the W87-1 warhead and new infrastructure to support long-term strategic stability.
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What are the key technical improvements of the Sentinel over Minuteman III?
How does the Sentinel's cost overrun impact U.S. defense spending?
What is the role of the W87-1 warhead in the Sentinel system?