WASHINGTON — Amid delays with the troubled LGM-35A Sentinel program, the US Air Force has now assessed that the service’s decades-old fleet of Minuteman III ICBMs could be extended to 2050, though doing so would carry risks, according to a new report.
In a review of Sentinel published by the Government Accountability Office [PDF] on Wednesday, the watchdog found that prolonging operations of the MMIII arsenal, maintained by Boeing, is “feasible,” and the Air Force is now assessing options for that extension. But doing so would come with complications, like a limited supply of parts needed to conduct flight tests that ensure the missile’s efficacy.
The Air Force plans to replace the MMIII arsenal gradually with the new Sentinel, which the Pentagon revealed in July 2024 is years delayed and 81 percent over budget, largely due to unforeseen issues with ground infrastructure. An original plan for Sentinel called for reusing MMIII silos, but officials have now determined that whole new silos will have to be constructed instead.
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Sen. Elizabeth Warren, a Massachusetts Democrat who has been critical of the Sentinel program, said in a statement to Breaking Defense following the report, “The Air Force repeatedly misled Congress about the need and real costs of the Sentinel program, and as a result, the Pentagon continues to burn billions. Today’s GAO report confirms that we desperately need an independent review to hold Pentagon officials accountable for wasting and mismanaging billions of taxpayer dollars.”
Unarmed MMIII tests are conducted regularly by the Air Force to ensure that the MMIII fleet is still operating well and to send a signal to allies and adversaries alike. Officials have said the missile continues to perform, though a test in 2023 ended in the Air Force aborting it early and blowing up a missile due to an “anomaly.” Following that event, House Armed Services Committee Chair Mike Rogers, an Alabama Republican, said in a statement that “further life extension is simply infeasible.”
But a report [PDF] published by the Federation of American Scientists in 2021 determined that extending MMIII to 2050 is “technologically feasible” and would entail replacing the missile’s solid rocket motors and guidance systems. The missile’s annual testing rate may also need to be reduced “to maintain a sufficient inventory of test assets,” the FAS report says. (The Defense Secretary in 2020 granted the Air Force a waiver to conduct fewer annual flight tests to conserve parts, GAO found.)
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Should the Air Force push ahead with keeping the Minuteman missiles online decades longer than originally planned, GAO found that “limited parts supply is a risk” to the test flight regimen and that “entire subsystems would need to be replaced to continue meeting operational requirements.”
Extending the life of the MMIII could present another problem, however, according to analyst Matt Korda: It undercuts the Sentinel’s original raison d’être.
“Now we’re being told that a life-extension campaign was possible all along, meaning that the primary justification for the Sentinel was inaccurate,” Korda, associate director of the Nuclear Information Project at FAS, told Breaking Defense. “So either we’re looking at a deliberate obfuscation to push through an unnecessary weapon system, or a case of multi-billion dollar mismanagement.
“Either way, everyday Americans will now be forced to pay the price for these skyrocketing costs unless this program gets scaled back,” he added.
Despite delays with Sentinel and the need to continue test flights, the “Air Force has not developed a plan for continued Minuteman III flight testing,” according to GAO. Prior to the Pentagon announcing the delay for Sentinel last year, the Air Force planned to retire MMIII in 2036, GAO says — a timeline that is now being revised.
GAO identified other issues with the Sentinel program, including that officials have not yet created a risk management plan or started construction of a Sentinel test facility that is needed to train personnel. The test facility, a mockup of a Sentinel silo, is planned for construction at Dugway Proving Grounds in Utah, according to GAO.
The GAO report issued six recommendations to the Pentagon, including that the service should create a risk management plan, assess personnel needs for the transition to Sentinel and develop a strategy for MMIII test launches post-2030. The DoD concurred with all six, the watchdog said.
Valerie Insinna contributed reporting.