WASHINGTON — In a milestone towards the modernization of America’s nuclear triad, the US Air Force has officially taken its first Minuteman III missile silo “offline,” Breaking Defense has learned.
The shuttering of launch facility LF 5E10, located at F.E. Warren Air Force Base in Wyoming, marks “the first operational MMIII silo to be taken offline” as officials prepare for the arrival of a new ICBM to take the Minuteman’s place as the land leg of America’s nuclear deterrent, a spokesperson for Air Force Global Strike Command said in response to questions about the facility.
The Air Force plans to replace its existing MMIII fleet with a new missile known as the LGM-35A Sentinel. Led by prime contractor Northrop Grumman, the Sentinel program is facing delays and steep cost increases as it seeks to procure 634 missiles — along with an additional 25 for development and testing — and deploy 400 of them in silos spread across vast missile fields in the Great Plains, stretching from Colorado to North Dakota near the Canadian border. The MMIII arsenal is maintained by Boeing.
“During the transition process, there will be no degradation of the land-based leg of the nuclear triad. The administrative decertification of LF 5E10 has no impact to the number of ICBMs that can be on alert in accordance with national policy and Air Force Global Strike Command continues to meet ICBM alert requirements providing the same level of readiness and reliability to U.S. Strategic Command and the President. This decertification does not pose any threat to our ability to respond decisively if called upon,” the spokesperson said.
“While the U.S. Air Force has modernized its ICBM force in the past, this is one of the largest modernization efforts ever undertaken by the U.S. government, similar in scale to President Eisenhower’s interstate program. Air Force Global Strike Command continues to move forward to enhance our command and control, improve security, integrate new technologies, and ultimately, ensure a weapon system that can respond to an increasingly complex world,” the spokesperson added.
While not a secret that LF 5E10 would be the first MMIII silo to be shut down — Global Strike Command actually announced plans for the move on its website back in April — it was unclear when the milestone would be achieved. However, during an Aug. 26 town hall hosted by officials from Minot Air Force Base in North Dakota, one of the service’s three installations that host nuclear missiles, Director of ICBM Modernization Maj. Gen. Colin Connor said that “the first site at F.E. Warren has been taken down.”
The Global Strike Command spokesperson declined to say when the silo went offline, citing operational security. In terms of what decertification involves, the spokesperson said broadly that “the aerospace vehicle was removed from the silo, critical equipment was removed from the launch facility, LF 5E10 was isolated from the network and removal and disposal of non-critical equipment has begun.”
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However, Matt Korda, associate director of the Nuclear Information Project at the Federation of American Scientists, told Breaking Defense that satellite imagery of the silo “indicated deviations from normal on-site activities during various pockets of time –– particularly from mid-August onwards, with the likely presence of vehicles on-site.”
Although it’s unclear what activities exactly were underway, “they are very likely related to the decertification and decommissioning process for that particular launch facility,” he said, as “It’s relatively rare to see significant activity at ICBM launch facilities, except during periods of maintenance or missile loading/unloading operations.”
The Air Force maintains 400 ICBMs ready to lift off at a moment’s notice — meaning 50 of the service’s 450 silos are empty. It’s unclear whether the decertified LF 5E10 recently housed a nuclear missile or not, but Korda’s assumption is that the silo was likely empty, as it would make more sense for the service to start decommissioning vacant launch facilities.
The silo’s shuttering “is an early step” in a long road ahead toward finishing Sentinel, Korda said, which he expected will face “more revelations about challenges that this program has as it continues on its way.”
Jon Wolfsthal, FAS’s director of global risk, noted that since Sentinel is still years away from being ready, “it’s surprising [the Air Force would] be pulling down operational silos” this soon, and questioned whether the service has truly thought through every step of the process.
“No one seems to have a sense of what the full plan is,” he said.
The Air Force is currently restructuring the Sentinel program following an 81 percent cost spike announced last year, which officials have said is largely driven by infrastructure complications. Officials halted work on the command and launch portion of the program as part of the restructuring, which Northrop CEO Kathy Warden revealed in July has since restarted.
But a key change for silos now comes in where they will be located: In May, the Air Force disclosed that the service has decided to dig new silos for Sentinel, rather than refurbishing ones that currently hold the MMIII fleet. A previous analysis of alternatives reportedly found that digging new silos was cost prohibitive, but officials have claimed the fresh approach can actually save money since they can get the work done faster, rather than needing to more slowly choreograph the transition to Sentinel by keeping a certain number of MMIII silos online. New silo sites can also address problems like flooding that have developed at existing facilities due to decades-long environmental changes, according to officials.
Korda, for his part, raised doubts that projections of cost savings would bear fruit.
“I would personally be very skeptical of claims that an unexpected thing that no one wanted to see happen is actually good for the program and will save money,” he said.
UPDATED 9/4/25 at 10:52 am ET with additional details of the decertification process.