Now that the United States Air Force is engaged in work on all segments of the LGM-35A Sentinel program, it will task the missile’s predecessor with standing guard a little longer.
The Air Force briefly halted infrastructure efforts for the Sentinel intercontinental ballistic missile (ICBM) in early 2025 as it looked at restructuring the program. The Air Force said it would need to build new underground silos for the Sentinel instead of reusing the 55-year-old Minuteman III infrastructure as planned, news website Defense One reported in May 2025. The Sentinels will replace the 400 Minuteman in hardened silos spread across missile fields in Colorado, Montana, Nebraska, North Dakota and Wyoming, according to Defense One.
With the restructuring comes a timeline revision for Sentinel deployment. The projected initial operational capability is now late 2033. The Air Force expects the Minuteman to serve until 2050, according to a September 2025 report from the Government Accountability Office (GAO). However, the service said it is examining the removal of the final Minuteman III before 2050, program executive officer for ICBMs, told Defense Daily in response to the GAO report. That’s because work on the Sentinel itself is progressing, according to the Air Force. “We’ve now had the opportunity to prototype and test every stage of the missile and they very much performed as we expect them to, which gives us confidence as we push forward on the path to get that program into flight test,” Ben Davies, president of defense systems for contractor Northrop Grumman, told the Air & Space Forces Association’s Air, Space & Cyber Conference in Washington, D.C., in September 2025, according to InsideDefense.com.
The Minuteman first deployed in 1970 and has remained viable and reliable through constant test launches and life-extension upgrades. The Minuteman III is the oldest deployed strategic ballistic missile in the world, according to the Air Force. The service projects the missile will reach the end of its service life in 2036, according to the GAO report.
“Air Force officials told us that although they are confident that Minuteman III can be used beyond 2030, even out to 2050, [although] they acknowledged there are [infrastructure] unknowns such as ground electrical subsystems and electronics that … could degrade,” the GAO report said, according to Air & Space Forces magazine.
The GAO report recommended the Air Force develop a plan to deal with those issues during the transition from Minuteman to Sentinel. The service agreed with the recommendations, according to the magazine.
An Air Force spokesperson said its Minuteman program office regularly conducts reviews to determine how long the ICBM fleet can feasibly serve, and the 2050 date is not linked to Sentinel program timelines, the magazine said.
“We see a lot of promise, both in the programs of record [such as the Sentinel], but also in the legacy systems [such as the Minuteman] that we have existing today,” U.S. Air Force Maj. Gen. Brandon Parker, director of global operations at U.S. Strategic Command, said at the Air, Space & Cyber Conference, according to a September 2025 Pentagon News report. “While we go through that modernization process, it’s equally important that we sustain the capabilities that we have today so that we can continue to deter and, if necessary, respond.”