A graphic illustration of LGM-35A Sentinel. (Jim Masie/Northrop Grumman)
The new LGM-35A Sentinel intercontinental ballistic missile being developed for the U.S. Air Force is on track with initial capability tests to allow for a decision by the end of the year on whether to build a prototype, the Air Force said Tuesday.
The program plans to “achieve a Milestone B decision by the end of 2026, while delivering an initial capability targeted for the early 2030s,” the Air Force said in a statement.
Defense weapons programs begin with the initial concept. Milestone B is when a project moves toward a prototype, and the performance, schedule and funding plans are set.
“This progress paves the way for the program’s next major operational milestone: the first missile pad launch, planned for 2027,” the Air Force said.
The booster will be integrated with the missile’s forward section to create the first fully assembled ground-test Sentinel missile.
“This pathfinder test missile is essential for verifying the weapon system’s design and preparing for the first Sentinel flight test, ensuring the future of our nation’s strategic deterrence,” the Air Force said.
Milestone C is the production of the weapon.
The advancements announced Tuesday “also solidified the early 2030s as the firm target for delivering initial capability,” the statement said.
The missile, which the Pentagon plans to take the place of the current LGM-30G Minuteman III ICBMs, would anchor the land-based portion of the triad for attacking enemy targets with nuclear weapons. The triad also includes sea-launched ICBMs from Ohio and future Columbia-class submarines, and manned bombers.
Northrop Grumman has said the Sentinel is designed to carry W87‑0 and W87‑1 thermonuclear warheads with a yield of between 300 kilotons and 475 kilotons of TNT more than 3,500 miles or more. The program will modernize the nuclear missile system that currently has over 450 silos. The Air Force said it was building 600 facilities across 40,000 square miles of U.S. territory, the contractor said.
The Air Force late last year announced that its plans to concentrate the manned bomber force on the new B-21 Raider bomber now under development, while maintaining the B-52 Stratofortress in a role as a standoff weapon delivery system. The B-1 Lancer and B-2 Spirit bombers will be phased out as the new B-21s enter service.
The Sentinel will replace the Minuteman III with hundreds of new silos spread across the north-central tier of the United States.
“Sentinel is a comprehensive, once-in-a-generation modernization of the entire land-based leg of the nuclear triad, a key component of the nation’s integrated deterrence posture,” the Air Force said. “It is a full-scale replacement of the missile, launch systems and command-and-control infrastructure with a new architecture designed with built-in adaptability for the digital era.”
The Air Force said the decision to build new missile silos “avoids the unpredictable costs and safety hazards of excavating and retrofitting 450 unique structures built over 50 years ago.”
The Air Force said it is actively preparing missile wings for the operational transition to Sentinel. That preparation “reached a visible milestone” last fall when the Air Force took a Minuteman III silo offline — “a carefully sequenced step in planning and executing the transition from Minuteman III to Sentinel.” The location of the silo and other details were not provided.
The effort is managed by Site Activation Task Force (SATAF) detachments established at F.E. Warren Air Force Base, Wyo.; Malmstrom Air Force Base, Mont.; Minot AFB, N.D.; and Vandenberg Space Force Base, Calif.
“The turnover of the first Minuteman III silo is a clear signal: we are making real, tangible progress in accelerating the Sentinel program and fielding significantly improved long-range strike capabilities,” said Gen. S.L. Davis, commander of Air Force Global Strike Command.
This month, Air Force-led teams will break ground on a prototype launch silo at Northrop Grumman’s site in Promontory, Utah.
“This crucial effort will allow engineers to test and refine modern construction techniques, validating the new silo design before work begins in the missile fields,” the Air Force said.
The Air Force said construction on permanent Sentinel launch facilities has already started. The first of three new Wing Command Centers is being set up at F.E. Warren, and critical test facilities are being erected at Vandenberg to support the future flight test campaign.
The Air Force said it and contractor Northrop Grumman successfully completed a full-scale qualification test of Sentinel’s Stage-2 solid rocket motor in July 2025. A successful Stage-1 qualification was achieved in March 2025.
The Air Force credited the pace of developments to the creation of Direct Reporting Portfolio Managers (DRPM) for Critical Major Weapon Systems last August.
The DRPM role places programs, including the Sentinel, under a single leader given authority to make decisions without additional approvals.
The Air Force Global Strike Command said in January 2025 that it expected about a 15-year minimum overlap between the first Sentinel silo going online and the last Minuteman III silo decommissioned.
“I think 15 years is probably an ambitious estimate,” Maj. Gen. Stacy Jo Huser, commander of the 20th Air Force in the Air Force Global Strike Command, said at the Los Alamos Study Group Exchange Monitor Annual Nuclear Deterrence Summit. “So, one thing that a lot of people don’t realize and our own air units don’t realize is the Sentinel is not just the missile. And this probably offends people in the room, but the missile is easy. The rest of it is the infrastructure.”
