The Senate Armed Services Committee wants a report from the Air Force and Pentagon about the possible deployment of 450, rather than 400, Sentinel intercontinental ballistic missiles.
The lawmakers asked for the study in a bill report published the same week the Department of Defense announced further cost overruns and developmental delays for LGM-35A Sentinel, which Northrop Grumman is building to replace the Minuteman III missile made by Boeing.
The Senate Armed Services Committee directed the Secretary of the Air Force, the Defense Department’s acquisition chief, and the head of U.S. Strategic Command to undertake the study in a report appended to the committee’s version of the 2025 National Defense Authorization Act.
The Air Force had targeted May 2029 for Sentinel’s initial operational capability, but the date will now be several years beyond 2029, the Pentagon said on Tuesday.
“The committee recognizes the unwillingness of the Russian Federation to engage in constructive discussions about the future of strategic arms control measures beyond the February 2026 expiration of the treaty between the United States of America and the Russian Federation on Measures for the Further Reduction and Limitation of Strategic Offensive Arms, commonly referred to as the New START Treaty,” the report reads.
“In addition, the People’s Republic of China has not demonstrated an interest in providing additional insight into, or enacting limitations upon, the expansion of its nuclear forces. Under such conditions, the committee believes it is prudent to begin examining options for adapting U.S. deterrence capabilities to account for worsening strategic threats, while reserving final decisions on whether to pursue such options until the post-New START Treaty international security environment becomes clearer.”
New START caps deployed U.S. and Russian strategic nuclear weapons, those with city-destroying power, to 1,550 warheads on a combination of no more than 700 intercontinental ballistic missiles, submarines, and heavy bombers.
On July 8, following a Nunn-McCurdy review, the Department of Defense said it reversed its 2020 decision to begin Sentinel engineering and manufacturing development. Sentinel’s lifecycle cost has grown to nearly $141 billion, 81% greater than the September 2020 estimate, the agency said.
The first Sentinel missiles to deploy were to carry W87-0 warheads provided by the National Nuclear Security Administration. Later missiles would use W87-1 warheads. The former are Minuteman III warheads that will be modified for use on the new missile. The latter, replacements for Minuteman III’s W78, will be newly manufactured weapons based on previously tested nuclear components.
A version of this story first appeared in Weapons Complex Monitor affiliate publication Defense Daily.