The Air Force inventory of silos able to launch Minuteman III intercontinental ballistic missiles (ICBMs) is in no immediate danger of dropping below the threshold of 400 established by Congress in the fiscal 2017 National Defense Authorization Act.
This information comes as the Air Force transitions from the 1970s-era Boeing LGM-30G Minuteman III to the planned Northrop Grumman LGM-35A Sentinel ICBMs in the years ahead, according to Air Force Global Strike Command (AFGSC).
AFGSC said that on April 3 it transferred Minuteman III Launch Facility (LF) 5E10 at F.E. Warren Air Force Base (AFB), Wyo., to Site Activation Task Force Detachment 10, which is responsible for new silos, maintenance, and communications for Sentinel at F.E. Warren. “Upon completion of an implementation plan within 30 days [of April. 3], LF 5E10 would be considered administratively transferred and decertified from Minuteman III generation requirements and transferred into caretaker status,” AFGSC said.
Under the 2010 New Strategic Arms Reduction Treaty (New START) with Russia, “only the removal of missile boosters was required,” AFGSC wrote on Friday in an email response to questions from Exchange Monitor affiliate Defense Daily. “In compliance with treaty deadlines, the United States removed intercontinental ballistic missiles from 50 of the 450 designated launch facilities. These 50 sites remained fully operational but without missiles installed. The removed boosters were placed in storage for potential future use, and the now-unloaded launch facilities remained subject to inspection under treaty provisions. Therefore, decommissioning a launch facility would reduce the total to 449, not 399.”
The Air Force removed Minuteman IIIs from 50 silos between 2014 and July 2017, but the service has said it kept those silos in “warm” status for future use.
“Today, Air Force Global Strike Command maintains up to 400 Minuteman III ICBMs on alert—24 hours a day, 7 days a week, 365 days a year—ensuring full compliance with both New START Treaty limitations and U.S. Strategic Command (USSTRATCOM) operational requirements,” AFGSC said on Friday. “While we do not currently deploy multiple independently targetable reentry vehicles (MIRVs) on our ICBMs, we retain the capability and continue to train and test for MIRV employment as required.”
The vast, decade-long Sentinel project is to kick off with the building of fiber optic communications lines in the spring of 2027.
The expiration of the New START Treaty next February may lead to a rethinking of minimum deterrence levels for the U.S. and whether ICBMs with multiple warheads–MIRVs–will be a way forward for the U.S. ICBM force. AFGSC has operated under the minimum deterrence rubric of 400 single warhead Minuteman IIIs with 50 in reserve.
A decade ago up until the revelation of the Sentinel program’s Nunn-McCurdy breach in January last year, Air Force plans called for refurbishing the old Minuteman III silos–and their steel and concrete–to accommodate the then called Ground Based Strategic Deterrent, now Sentinel, more quickly and cheaply. Yet, tests of a mock Minuteman III silo this year at Vandenberg Space Force Base, Calif., showed that conversion of such silos to accommodate the larger Sentinel missile would be much more complex than the service had thought, and Air Force officials have pointed to environmental problems in Minuteman III silos, such as lead paint, asbestos, and water damage.
Since the enactment of the fiscal 2017 NDAA, Congress has stipulated that the Air Force not reduce its stock of Minuteman IIIs at any time below 400 with two exceptions–regular “maintenance or sustainment” of ICBMs and “ensuring the safety, security, or reliability of intercontinental ballistic missiles.” Starting in fiscal 2023, the NDAA has allowed a third exception for the Air Force dipping below 400 ICBMs–“facilitating the transition from the Minuteman III intercontinental ballistic missile to the Sentinel intercontinental ballistic missile.”
Sentinel is to achieve initial operational capability by 2033, but the Air Force is also planning to sustain the Minuteman III until 2050.
Exchange Monitor affiliate Defense Daily first published a version of this article.