LGM-35A Sentinel missile cost climbs, schedule slips

An artist's portrayal of the Northrop Grumman LGM-35A Sentinel ICBM. (Northrop Grumman)

The US Air Force's (USAF's) LGM-35A Sentinel intercontinental ballistic missile (ICBM) programme is to cost at least 37% more and enter service two years later than anticipated, the USAF said in a 19 January statement.

The Program Acquisition Unit Cost (PAUC) has increased from a projected USD118 million in 2020 to roughly USD162 million per missile in December 2023. Most of the overrun is due to cost increases in the command-and-control (C2) and missile silo infrastructure, the USAF said. The missile's initial entry into service is now delayed until 2028 or later from 2026.

The LGM-35A programme entails extensive reconstruction of missile silos and C2 centres designed for the LGM-30G Minuteman III ICBM, which first entered service in 1962. According to the USAF statement, the Sentinel programme entails building over 400 launch facilities, including thousands of miles of fibre-optic cable, 7,500 miles of utility corridors, and a flurry of real estate easements with hundreds of landowners.

Though the details were publicly unknown, overruns were widely expected following a June 2023 Government Accountability Office (GAO) report, which found that “Sentinel's master schedule contains many deficiencies and cannot be used to effectively manage the execution of the program”.

Secretary of the Air Force Frank Kendall told a Washington, DC, think-tank crowd in November 2023 that the LGM-35A programme had encountered “unknown unknowns” and was due for a re-baseline.

“As we get more into the programme, as we understand more deeply what we're actually going to have to do, we're finding some things that are going to cost money. There's no question about that,” Kendall said, citing complexities of rebuilding C2 and launch control complexes.