Northrop Grumman (NYSE: NOC) and the U.S. Air Force have fully assembled an inert Sentinel intercontinental ballistic missile in a vertical orientation at Vandenberg Space Force Base, marking a step toward a planned flight test in 2027, according to a company press release.

The exercise, called Pathfinder, involved transporting missile components from multiple locations across the U.S. to Vandenberg Space Force Base, where engineers stacked and de-stacked the inert missile on a test pad over a four-month period. The operation tested mechanical processes including specialized transport, mobile crane use, and interface verification.

The assembly confirms that all missile stages, propulsion elements, the shroud, and associated components have been integrated into a single missile configuration. Northrop Grumman and the U.S. Air Force's 719th Test Squadron also completed the first flight test Critical Design Review, which the companies say confirmed the missile's design maturity and hardware testing meet Air Force requirements for performance, safety, and schedule.

Amanda Davis, vice president and general manager of strategic deterrent systems at Northrop Grumman, said the vertical assembly "demonstrates the momentum toward test launching Sentinel in 2027 and having missiles on alert by the early 2030s."

The Sentinel program is intended to modernize the ground-based leg of the U.S. strategic nuclear triad, replacing the existing Minuteman III missile system. Northrop Grumman leads a team of more than 500 partners under an engineering and manufacturing development contract. The program employs more than 10,000 workers nationwide and is designed to remain viable through 2075.