(Bloomberg) -- The US Air Force and Defense Department are facing potential schedule delays for the new intercontinental ballistic missile that’s central to efforts to modernize the nation’s nuclear arsenal, less than three years into its development.

The $96 billion Sentinel ICBM, to be built by Northrop Grumman Corp., may miss its goal of initial deployment in May 2029 by as much as two years, according to information presented at a high-level Pentagon review last month. Among the causes cited: A shortage of skilled engineers and supply-chain problems. The potential delays haven’t previously been disclosed.

The Sentinel program has wide bipartisan congressional support because it’s seen as key deterrent against China, which is rapidly increasing its nuclear arsenal. Still, any major delay may embolden arms control advocates who have pressed for its termination in favor of extending the life of 1970s-era Minuteman III missiles.

Defense Secretary Lloyd Austin may be asked about the program’s status Thursday during a House defense appropriations subcommittee hearing on the Pentagon’s fiscal 2024 budget request.

Without confirming specifics of the potential timeline, the Air Force said in a statement that it’s reviewing ways to mitigate the potential delays. “In the current macroeconomic environment” the Air Force is seeing “challenges with hiring qualified staff due to a competitive labor market and increasing” parts delivery delays from “supply chain constraints,” according to the statement.

The program office is “updating its acquisition strategy to address these challenges and take advantage of opportunities to preserve” the weapon’s initial deployment date, the service said. The Air Force said it has “identified and is ready to execute acquisition strategy changes to reduce risk and optimize schedule, wherever possible.” 

The Air Force said it plans to accelerate activities “to mitigate deployment and production risks” when possible. Those actions “will result in a new program schedule.” 

“While some interim activities and milestones will change,” specific acquisition timelines are “yet to be finalized,” according to the Air Force. The service said it believes “the overall schedule risk under these changes will be lower than before.” 

Nuclear Triad

The Sentinel is part of a push to update the nation’s arsenal that’s designed to deliver nuclear weapons by air, land and sea — the so-called nuclear triad. The triad modernization remains a key Pentagon priority under the Biden administration after it was jump-started by President Barack Obama and continued by President Donald Trump.

The Air Force is requesting $4.5 billion in fiscal 2024 and $38.5 billion through fiscal 2028 for the Sentinel program. The figure includes $19.4 billion in procurement. The service plans to buy 659 missiles from Northrop Grumman, which includes 25 test items and 634 missiles to replace Minutemen in silos and provide for spares.

Northrop Grumman said in a statement that the Sentinel program has met “milestones to date, including recent successes in hypersonic wind tunnel testing, and a stage-one solid rocket motor static fire.” 

“We are closely partnered with the Air Force,” the company said. “We are jointly working to address the effects of supply chain disruption and other macroeconomic factors on the program.”

Pentagon spokesman Jeff Jurgensen said the Air Force is working with department acquisition officials “to identify further steps to reduce schedule risk.” Any specific actions to prevent or mitigate potential delays “remain pre-decisional and will be announced at an appropriate time,” he said. 

The program’s “Critical Design Review,” now scheduled for May 2024, faces a potential nine-month delay, according to information presented at a Feb. 7 “In-Process Review.” The critical design review, which occurs during the development phase, examines whether the ICBM design is stable and is expected to meet system performance requirements.

A second key milestone before deployment  — a Pentagon decision to proceed into production — may slip as much as nine months from its current January 2026 estimate unless steps are taken to remedy that.

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