Department of Defense Announces Results of Sentinel Nunn-McCurdy Review

On January 18, 2024, the Air Force notified Congress that the Sentinel program exceeded its baseline cost projections, resulting in a critical breach under the Nunn-McCurdy statute. A critical Nunn-McCurdy breach occurs if the Program Acquisition Unit Cost (PAUC) or Average Unit Procurement Cost (APUC) increases by 25 percent or more over the current Acquisition Program Baseline. By statute, the respective program must be terminated unless the Under Secretary of Defense for Acquisition and Sustainment (USD(A&S)) certifies to Congress that the program meets established criteria to continue.

The Office of the Secretary of Defense (OSD) executed its statutory responsibilities by conducting a comprehensive, unbiased review of the program to determine what factors led to this cost growth and whether to certify the continuation of the program. Senior subject matter experts from various disciplines and departments actively contributed to the review.

Based on the results of the review, Dr. William A. LaPlante, the USD(A&S) who served as the DoD lead for the review and is the Milestone Decision Authority for the program, certified that the Sentinel program met the statutory criteria to continue. This criterion included that:

•    Continuation of the Sentinel program is essential to national security.

•    There are no alternatives to the program which will provide acceptable capability to meet the joint requirements at less cost.

•    The new estimates of the program acquisition unit cost or procurement unit cost have been determined by the Director of Cost Assessment and Program Evaluation (CAPE) to be reasonable.

•    The program is a higher priority than programs whose funding must be reduced to accommodate the growth in cost of the program; and

•    The management structure for the program is adequate to manage and control program acquisition unit cost or procurement unit cost.

In certifying the program to continue, LaPlante rescinded Sentinel's Milestone B approval, or the point at which an acquisition program is authorized to enter the engineering and manufacturing development phase. He also directed the Air Force to restructure the Sentinel program to address the root causes of the breach and ensure an appropriate management structure is in place to control costs in the future.

Total program acquisition costs for a reasonably modified Sentinel program are estimated by CAPE to be $140.9 billion, an increase of 81 percent compared to estimates at the program's previous Milestone B decision in September 2020. The Nunn-McCurdy review determined that most of the cost growth is in Sentinel's command and launch segment, which includes the launch facilities, launch centres, and the process, duration, staffing, and facilities to execute the conversion from Minuteman III to Sentinel.

"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 said. "There are reasons for the cost growth, but there are no excuses. We are already working to address the root causes, and more importantly, we believe we are on the right path to defend our nation while protecting the sacred responsibility the American taxpayer has entrusted us with."

"The nuclear Triad is the foundation of our national defence, and as our competitors modernize their nuclear forces, the urgency of pacing the threat is reflected in our Nuclear Posture Review," LaPlante added. "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. Having completed a comprehensive and objective assessment of the program, it is clear that the Sentinel program remains essential to U.S. national security and is the best option to meet the needs of our warfighters."

Preserving schedule will be a key consideration during the program's restructuring; however, a delay of several years is currently estimated.

While the U.S. nuclear arsenal remains safe, secure, and effective, most nuclear deterrent systems are operating beyond their original design life, and there is little or no margin between the end of their effective life and the fielding of their replacements. These modernized capabilities are needed to avoid any gaps in our ability to field a credible and effective deterrent.

The 2022 Nuclear Posture Review concluded that a modernized Triad remains necessary to deter strategic attack, assure allies and partners, and achieve U.S. objectives if deterrence fails. The Sentinel program was established to modernize and replace the land leg of the Triad, currently comprised of the Minuteman III Intercontinental Ballistic Missile (ICBM) weapon system.

"The land leg of the Triad is an essential component of our nuclear enterprise, undergirding our national security," said Under Secretary of the Air Force Melissa Dalton. "The Air Force is committed to restructuring the Sentinel program to address the findings of this review and modernizing our ICBM force to ensure its effectiveness against future threats while ensuring no capability gaps during the transition from Minuteman III to Sentinel."

Today's dynamic security environment only underscores the importance of our nation's nuclear deterrent to U.S. defence strategy and, specifically, the extended deterrence commitments we have made to allies and partners.

"Our U.S. nuclear forces are ready, as they have been for decades, to deter our adversaries and respond decisively should deterrence fail," General David W. Allvin, Chief of Staff of the Air Force. "We face an evolving and complex security environment marked by two major nuclear powers that are strategic competitors and potential adversaries. While I have confidence in our legacy systems today, we must modernize of our nuclear Triad. A restructured Sentinel program is essential to ensure we remain best postured to address future threats."