Updated January 2023
The land-based leg of the U.S. nuclear triad is currently composed of 400 deployed Minuteman III Intercontinental Ballistic Missiles (ICBMs) based out of Malmstrom, Minot, and Warren Air Force bases in underground silos stretching across Montana, North Dakota, Wyoming, Nebraska and Colorado. Each ICBM carries one warhead — either the W87 or the W78 — but could theoretically hold two or three warheads each. In 2015, the Air Force completed a decades-long, $7 billion program to extend the life of the Minuteman III through at least 2030. The Air Force has referred to the recently refurbished stock of ICBMs as “basically new missiles except for the shell.”
Ground Based Strategic Deterrent
As a part of the $1.5 trillion nuclear modernization plan, the Air Force plans to replace the Minuteman III with a completely new ICBM, the Ground Based Strategic Deterrent (GBSD); a new ICBM warhead, the W87-1; and modernized launch facilities. The GBSD is expected to be capable of carrying single or multiple warheads and will likely have a greater range than existing ICBMs, though it is unlikely to be able to target countries like China, North Korea and Iran without flying over Russia.
Northrop Grumman, which was the eventual sole bidder for the GBSD and also has the contract to build the Air Force’s new B-21 nuclear bomber, was awarded an initial $13.3 billion engineering and manufacturing development (EMD) contract in September 2020 for the GBSD. The Air Force plans to buy 659 missiles from the defense contractor, 400 of which would be deployed and the rest used for testing and spares, at a cost of at least $95 billion. When accounting for total life-cycle costs, the Department of Defense projects the total cost of the GBSD could be as high as $264 billion. This number does not include costs for the W87-1, which the Government Accountability Office estimates will cost up to $14.8 billion.
The Biden administration previously considered additional service life extension for the Minuteman III as an alternative to GBSD. However, it now appears as though the administration plans to proceed with the transition to the GBSD, now named the Sentinel. The Biden administration’s 2022 Nuclear Posture Review indicates that the “Sentinel will replace Minuteman III one-for-one to maintain 400 ICBMs on alert.” Accordingly, the DOD requested $3.6 billion for GBSD EMD in FY 2023.
The Future of ICBMs
The main rationale for maintaining silo-based ICBMs is to complicate an adversary’s nuclear strategy by forcing them to target 400 missile silos dispersed throughout the United States to limit a retaliatory nuclear strike, which is why ICBMs are often referred to as the “nuclear sponge.” The development of sea-based nuclear weapons, which are essentially undetectable, and air-based nuclear weapons, which provide greater flexibility, has led to questions about the continuing value of ground-based ICBMs as they become technologically redundant.
Furthermore, U.S. ICBMs are constantly held in a state of high alert. This may increase the risk of accidental war over a false alarm from the United States’ missile detection system. Indeed, there have been several near catastrophes in the past. For these reasons, there have been calls to reexamine the future of the ICBM leg of the triad to determine when advancing technology will allow for adequate deterrence in its absence.
