The US Air Force and Northrop Grumman are targeting a first flight test of the LGM-35A Sentinel in 2027, as the next-generation intercontinental ballistic missile moves closer to replacing the aging Minuteman III.
Initial operational capability expected in the early 2030s.
Sentinel is designed to modernize the land-based leg of the US nuclear triad, which has relied on Minuteman III missiles since the 1970s.
The system will cover an operational area of roughly 32,000 square miles (82,880 square kilometers) across multiple states and includes not only the missile itself, but also upgraded launch infrastructure, command-and-control systems, and transport equipment.
Development is being carried out using a phased acquisition approach intended to enable earlier testing and validation.
According to the company, this allows design adjustments to be incorporated during development rather than after full system completion, potentially reducing delays later in the program.
Testing
The missile has progressed from digital design into early prototyping and hardware testing.
All major propulsion components have undergone prototype testing, and the first three-stage booster has been assembled to validate manufacturing processes and design assumptions.
Solid rocket motors for multiple planned flight tests are already in production.
A series of subsystem tests has also been conducted, including interstage separation trials to ensure spent rocket stages detach cleanly during flight, and a shroud test to validate the payload’s protective cover.
Guidance and control systems have undergone stress testing, including sled-based trials simulating flight conditions to evaluate the durability of navigation components.
Supporting Infrastructure
In parallel, work is underway on supporting infrastructure.
The program includes a new modular launch silo design intended to replace or supplement existing Minuteman III silos, with a prototype structure now in development to assess construction methods and performance.
Transport systems for moving missile components have also been tested in long-distance trials to evaluate security and reliability.
The program further includes a digital launch support system, which recently completed its critical design review and is moving into the build and test phase.
Overall, Sentinel involves a supply chain of more than 500 companies and a workforce exceeding 10,000 personnel.
The missile is expected to remain in service through at least 2075.
