The US Air Force (USAF) and Northrop Grumman have achieved a key milestone in the LGM-35A Sentinel intercontinental ballistic missile (ICBM) modernisation by completing the full-scale qualification test of the stage-two solid rocket motor.
The test, performed by the 717th Test Squadron, took place at the Arnold Engineering Development Complex on 20 July 2025.
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It is part of the USAF’s ongoing initiative to upgrade its land-based nuclear deterrent capabilities.
The motor was tested in a vacuum chamber designed to replicate conditions at high altitudes.
The evaluation gathered critical data on the motor’s performance, including its thrust profile and guidance capabilities through the thrust vector control system.
Brigadier General William Rogers, Air Force Nuclear Weapons Center ICBM Systems Directorate director and Air Force ICBMs programme executive officer, said: “This test reflects our disciplined digital engineering approach and the continued momentum behind the Sentinel programme. We’re not just testing hardware — we’re proving that our models are accurate, our development timeline is achievable, and the system will be ready to deliver when called upon.”
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By GlobalDataThe stage-two motor represents one of the trios of booster segments that constitute the Sentinel missile’s three-stage configuration.
This test is one among several aimed at qualifying the stage-two design and confirming predictive performance models created within a digital engineering framework.
Insights from this test will inform design refinements and mitigate technical risks as the program advances towards production.
Following the successful stage-one rocket motor test in March at Northrop Grumman’s Utah facility, this latest milestone further validates the alignment between actual performance and digital model predictions.
Rogers added: “This isn’t just about one motor test. It’s about building confidence — in our engineering; in our program schedule; and, most importantly, in our ability to deter aggression and defend the nation.”
The Sentinel programme benefits from a model-based design strategy enabling engineers to simulate system behaviour more accurately, predict performance more reliably, and reduce dependence on physical prototypes.
Further stage-two qualification tests are scheduled throughout the year by the USAF and Northrop Grumman to assess additional motor components under various environmental conditions.
In May, the USAF conducted a successful test launch of an unarmed Minuteman III intercontinental ballistic missile (ICBM) from Vandenberg Space Force Base in California.
The Minuteman III ICBM will eventually be replaced by the LGM-35A Sentinel.
