The US Air Force is evaluating whether Boeing’s Minuteman III intercontinental ballistic missiles—on alert since the 1970s—can remain in service until 2050, adding 11 years to their planned life, according to a newly declassified Government Accountability Office assessment. The option is being weighed as Northrop Grumman’s LGM-35A Sentinel replacement faces schedule delays, cost growth and a program overhaul through 2026.

Why an Extension Is on the Table

The GAO says Sentinel’s delays mean the service must operate Minuteman III longer than planned and formally evaluate life-extension paths, while tracking risks such as aging ground-electrical subsystems and diminishing manufacturing sources. Air Force officials told auditors the missile inventory and boosters are performing well, but sustaining parts, supply chains and skilled personnel will be increasingly challenging over time.

Costs, Delays and a 2026 Restructure

Sentinel’s overall program cost has ballooned to at least ~$141 billion—an 81% jump from 2020 estimates—triggering a statutory review and a multi-year restructure. The first flight test, once slated for December 2023, is now no earlier than March 2028, with no firm deployment schedule until the restructure concludes in 2026. Independent budget analysts also project nearly $1 trillion in nuclear-force spending through 2034, complicating procurement trade-offs.

Silo Strategy Shifts

Replacing 400 Minuteman III missiles requires an intricate choreography: pulling legacy missiles, refurbishing launch facilities, and installing Sentinels without reducing alert levels. The Air Force now expects to build many new silos—alongside select refurbishments—with some sites potentially outside existing federal land footprints. Leaders argue that fresh construction could ultimately mitigate schedule and cost pressures compared with re-use at scale.

Political Pressure and Arms-Control Debate

The extension prospect strengthens arguments from arms-control advocates on Capitol Hill who question Sentinel’s affordability and timeline, pressing the Pentagon to examine alternatives and risk-reduce the transition. Parallel legislative proposals and oversight letters seek deeper cost transparency and guardrails as the Department of Defense re-baselines the program.