The Sentinel ICBM program will continue even though it has largely surpassed its initial cost estimates, the US Department of Defense has confirmed.
On January 18, 2024, the US Air Force notified Congress that the Sentinel program exceeded its baseline cost projections, resulting in a critical breach under the Nunn-McCurdy statute. This statute mandates a program review if costs rise by 25% or more above the baseline, which could lead to program termination.
The US Office of the Secretary of Defense (OSD) conducted a comprehensive review led by Dr. William A. LaPlante, Under Secretary of Defense for Acquisition and Sustainment, who confirmed on July 8, 2024, that the program met the necessary criteria to continue.
“We are fully aware of the costs, but we are also aware of the risks of not modernizing our nuclear forces and not addressing the very real threats we confront,” LaPlante commented. “Sentinel is a truly historic program to modernize the land leg of the Triad, and its scale, scope, and complexity are something we haven’t attempted as a nation in 60 years.”
The Sentinel program, aimed at modernizing the land leg of the US nuclear Triad, will undergo restructuring to manage future costs more effectively. This includes rescinding the program’s Milestone B approval and addressing the root causes of the cost increase.
“The Nunn-McCurdy review determined that the majority of the cost growth is in Sentinel’s command and launch segment, which includes the launch facilities, launch centers, and the process, duration, staffing, and facilities to execute the conversion from Minuteman III to Sentinel,” the Pentagon explained.
Total program costs are now estimated at $140.9 billion, up 81% from the previous estimate in September 2020. The restructuring process is expected to delay the program by several years.
What is the Sentinel ICBM program?
The Minuteman III, the intercontinental ballistic missile (ICBM) that currently composes the ground-based portion of the US nuclear deterrence Triad, was developed by Boeing and has been in service for over half a century, with its first deployment dating back to June 1970.
Since 2019, Northrop Grumman, Lockheed Martin, and the USAF have collaborated on developing a replacement.
The upcoming LGM-35A Sentinel ICBM, which comprises the Mk21A reentry vehicle and the W87-1 nuclear warhead, is anticipated to be in use by 2030. The USAF seeks to acquire over 600 Sentinel missiles to substitute the Minuteman III ICBM.