The United States Air Force assembled an inert LGM-35A Sentinel intercontinental ballistic missile (ICBM) at Vandenberg Space Force Base, California, marking a significant achievement ahead of its planned 2027 test launch. “This is more than a milestone, this integration demonstrates our commitment to moving forward with the pace necessary to modernize the ground-based leg of our nuclear triad,” U.S. Air Force Gen. Dale White, director of Critical Major Weapon Systems for the Department of War, said in a September 2026 service news release.
Technicians from the U.S. Air Force and manufacturer Northrop Grumman completed the Sentinel’s “vertical stacking,” culminating a four-month exercise called Pathfinder, which focused on “practical challenges of handling the new ICBM,” according to the website Interesting Engineering. Those challenges included moving the Sentinel’s components across the U.S. to Vandenberg Space Force Base.
“Executing this test campaign proved that our logistics pipeline and test operations work in complete lockstep,” U.S. Air Force Maj. Gen. William Rogers, the service’s portfolio acquisition executive for ICBMs, said in the news release. “From cross-country transport and specialized crane lifts to precision interface checks on the [launch] pad, bringing all of these elements together validated our technical baselines and proved Sentinel is ready to support the next phase of development.”
The Sentinel program represents a major effort to modernize the ground-based leg of the U.S. nuclear triad. It includes new launch facilities and underground silos. The Department of War expects the missile to enter operational service in the 2030s, eventually replacing the 400 Cold War-era Minuteman III ICBMs standing guard in hardened silos across Colorado, Montana, Nebraska, North Dakota and Wyoming.
“The deliberate progress being made on Sentinel ensures that, for decades to come, there will be no doubt in the minds of our adversaries about the credibility and readiness of our nation’s nuclear deterrent,” U.S. Navy Adm. Richard Correll, Commander of U.S. Strategic Command (USSTRATCOM), has said. USSTRATCOM’s primary mission is strategic deterrence, and it operates, manages and plans for the use of the nation’s nuclear triad, in addition to having the mandate to execute global strike missions.
Previously, the Sentinel’s progress came as the U.S. Air Force tested different stages of the missile — such as its solid-rocket motor and reentry vehicle — independently. “This proves all missile stages, propulsion elements, the shroud and associated components have been fully integrated into a single missile configuration,” a Northrop Grumman news release said.
The Air Force Test Center’s 719th Test Squadron also carried out a critical design review performed in parallel with the Sentinel’s assembly. It confirmed the stringent requirements for the missile’s performance, safety and mission assurance ahead of flight testing scheduled in 2027.
Officials described both the Pathfinder exercise and the test squadron’s review as a demonstration of the program’s maturity.
“Sentinel is no longer conceptual or designs for what the nation’s next-generation ICBM looks like,” White said in the news release. “It’s a physical, fully integrated system that is one major step closer to being ready for flight testing.”