The U.S. Air Force, working with Northrop Grumman, successfully completed a full-scale qualification test of the stage-two solid rocket motor for the LGM-35A Sentinel intercontinental ballistic missile (ICBM) on July 20.
The test was conducted by the 717th Test Squadron at Arnold Engineering Development Complex, a key site for high-fidelity propulsion and systems evaluation.
The test was carried out in a vacuum chamber, replicating high-altitude conditions, and focused on evaluating the motor’s thrust, burn characteristics, and thrust vector control system. The data will support final design adjustments and inform future production planning.
“This test reflects our disciplined digital engineering approach and the continued momentum behind the Sentinel program,” said Brig. Gen. William S. Rogers, Air Force program executive officer for ICBMs and director of the ICBM Systems Directorate at the Air Force Nuclear Weapons Center. “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.”
The stage-two motor is the second of three solid-fuel booster segments that make up the Sentinel ICBM. This test is part of a broader series of evaluations designed to qualify each stage of the missile and validate the performance predictions created through digital engineering tools. These models, developed in partnership with Northrop Grumman, are intended to streamline development, improve accuracy, and reduce long-term program costs.
“This isn’t just about one motor test,” Rogers added. “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 missile program, originally designated the Ground Based Strategic Deterrent (GBSD), is being developed to replace the aging LGM-30G Minuteman III ICBM fleet, which has been in service since the 1970s. The Sentinel is designed to serve as the land-based component of the U.S. nuclear triad well into the second half of the 21st century.
Officials say the model-based design approach has allowed teams to evaluate thousands of performance scenarios before physical testing, reducing risk and shortening development timelines. The stage-two test at Arnold AFB will be followed by additional qualification trials under varied environmental and stress conditions throughout the year.
According to Northrop Grumman, the LGM-35A Sentinel integrates upgraded propulsion, enhanced command-and-control capabilities, and hardened digital architecture to withstand future threats. The missile is being developed to meet evolving strategic deterrence requirements while maintaining reliability, survivability, and precision.