No propellant, no warhead, and no plan to launch it. Even so, an inert LGM-35A Sentinel stood upright at Vandenberg Space Force Base in California, fully stacked, in what Northrop Grumman and the US Air Force call the Pathfinder exercise.
All three stages, the propulsion systems, the shroud and the main associated components were integrated in an operational configuration. The pieces had been brought in from points across the country, moved with specialised transport and mobile cranes. Then the missile was taken apart again. Under the hood, this is a fitting and a rehearsal: the aim was to show that moving, assembling and preparing a Sentinel on a launch pad can be done safely, and that the interfaces between the elements line up.
Northrop Grumman said the vertical assembly “demonstrates the design and integration of the missile and is a major step toward the Sentinel missile’s design and suitability evaluation for flight test in 2027.”
A design review alongside
At the same time, the Air Force’s 719th Test Squadron and Northrop Grumman finished the first Critical Design Review tied specifically to the flight test. The review found the design and hardware testing mature enough to proceed toward the 2027 launch. As aviacionline noted, the programme is starting to shift from validating individual components to evaluating the whole system, and stacking the missile checks one of the hardest integration points before any real flight.
Northrop Grumman says the programme remains on track for that first flight test in 2027 and for initial capability in the early 2030s.
The wider programme
Sentinel will progressively replace the Minuteman III, in service since the 1970s, as the land-based leg of the US nuclear triad. The effort is bigger than a missile. It includes new launch systems, silo infrastructure, command and control centres and a digital architecture. The Air Force plans to deploy it at the current bases: F.E. Warren in Wyoming, Malmstrom in Montana and Minot in North Dakota.
The progress looks better against the start of 2026, when the Air Force was still restructuring the programme. Back then, the advances included a three-stage ground test missile and qualification testing of the second-stage solid rocket motor.
The scale explains the timeline. Northrop Grumman leads a team of more than 500 companies and over 10,000 people, with the goal of keeping the system operational until 2075.
