The US Air Force is testing the LGM-35A Sentinel, its next-generation intercontinental ballistic missile (ICBM). will have to dig entirely new nuclear missile silosThe unexpected development will add new complexity to the troubled project, which is already struggling with cost and schedule delays.
Initially, the Air Force hoped that a more efficient approach would be to retrofit the 55-year-old silos that house existing Minuteman III ICBMs to launch Sentinel missiles. However, a test project at Vandenberg Space Force Base in California made it clear that this approach would cause more problems and cause the program to be further delayed and over budget.
Test Project Reveals Risks of Adaptation Approach
“As the [Sentinel] program continues its restructuring activities, Air Force analysis continues to confirm unacceptable risks to cost, schedule and weapon system performance from the original baseline strategy of converting Minuteman III silos,” an Air Force spokesman said Tuesday. SözcüData from a test launch facility conversion project at Vandenberg Space Force Base confirms the impacts of unknown site conditions combined with significant cost and schedule overruns.
To minimize these and other risks, the Air Force plans to build new missile silos, mostly on land it owns. This decision would reuse existing missile bases but not the 55-year-old silos.
Sentinel Program Faces Nunn-McCurdy Breach
The Sentinel program is a critical Air Force project that aims to replace the current Minuteman III ICBMs, which form the land-based pillar of the U.S. nuclear deterrent and are nearing the end of their life. Built by Northrop Grumman, Sentinel is a massive modernization project spanning thousands of miles across the Great Plains region. Originally expected to cost $77,7 billion, future cost projections for the project have so far exceeded budget that they triggered a review process known as the critical Nunn-McCurdy breach in January 2024.
After that review, the Pentagon concluded that Sentinel was indispensably critical to national security, but ordered the Air Force to restructure the program to contain costs. But further study of the program shows potential problems remain.
Northrop Grumman Official Admits Need for New Silos
In a March 2024 briefing with reporters, a Northrop Grumman official who discussed the Nunn-McCurdy breach and the complexities of the program acknowledged that further examination of the conditions of existing silos could force the program to dig new ones. “There are no plans to dig new holes at this time,” the official said at the time, “but there is certainly the potential that as they examine more silos, given the site conditions of the terrain, some of them may not be [reused]. The Air Force’s latest statement suggests that potential is becoming a reality.
Air Force Looks for Ways to Improve Structure
The head of Air Force Global Strike Command, Gen. Thomas Bussiere, said in a virtual forum last week that the service is still examining the structure of the Sentinel program and looking for ways to improve it. Bussiere said the Nunn-McCurdy process was stressful for the department but provided an opportunity to reexamine and clarify how these facilities are designed and how they will be implemented with new capabilities. He added that after the review, the Air Force began exploring ways to repurpose existing land for Minuteman silos, if not the silos themselves, and is looking at other federally owned land to support ICBM sites.
Maintaining Deterrence is Critical in the Transition to the Digital Age
Gen. Bussiere emphasized that the service will need to keep a minimum number of ICBMs on alert to maintain the nation’s nuclear deterrent as it transitions from its legacy analog command-and-control architecture to Sentinel’s new, digital-era control functions. Getting that balance right will be a complex process, Bussiere said, considering that the scale of this project could outshine even the Eisenhower administration’s interstate highway system. “This is going to be a delicate ballet between [operations] and maintenance, acquisition, a bunch of partners that are part of this program, to make sure that we get this right. Frankly, we’ve never done this before at this scale and complexity,” he said. The Air Force’s decision to build the new silo is an indication of the challenges facing the Sentinel program and the complexity of the U.S. effort to modernize its nuclear deterrent.
