Northrop Grumman completes first qualification test of Sentinel stage-two solid rocket motor

Northrop Grumman said on Tuesday that the company and the U.S. Air Force completed the first qualification test of a stage-two solid rocket motor for the LGM-35A Sentinel Intercontinental Ballistic Missile.

The test was completed at the Air Force Arnold Engineering Development Complex in Tullahoma, Tenn., and “conducted in a vacuum chamber simulating flight conditions, allowing evaluation of the thrust vector control system, which steers the missile,” the company said. “Engineers designed Sentinel in a digital model-based environment, which accelerates design, reduces costs, and minimizes the need to ‘bend metal’ for each design enhancement.”

Such tests are to show whether solid rocket motors meet Air Force reliability and quality standards.

The engineers “will compare performance data from the test to predictions from our digital models, validating the motor performs as expected,” Northrop Grumman said.

“Northrop Grumman and the Air Force have tested all three stages of the Sentinel missile,” the company said in the release. “This test is the first of a series intended to validate digital models and finalize the stage-two rocket motor design” to provide “critical data for continued progress in missile design, testing and support systems.”

Sentinel, an intercontinental ballast missile (ICBM) currently being built by Northrop Grumman, will eventually replace the Boeing-made Minuteman III as the Air Force’s silo-based, nuclear-armed ICBM sometime in the 2030s while the Minuteman III is still commissioned. The new missile will initially carry W87-0 warheads provided by the National Nuclear Security Administration’s Lawrence Livermore National Laboratory in California.

The Air Force is restructuring the program after a critical Nunn-McCurdy breach announced by the service in January 2024, and that restructuring/new integrated schedule is to happen by next summer.

The Senate wants the U.S. Air Force to consider simultaneous construction of Sentinel silos for the three missile wings–the 90th at F.E. Warren Air Force Base (AFB), Wyo.; the 91st at Minot AFB, N.D., and the 341st at Malmstrom AFB, Mont.–as lawmakers take a stab at what makes sense to reduce Sentinel costs and speed up fielding of the future ICBM.

Exchange Monitor affiliate Defense Daily originally published a version of this story.