If all goes according to plan, the Sentinel program will go operational in 2030 and serve through 2075.
This year, America’s Minuteman III nuclear intercontinental ballistic missile (ICBM) will be fifty-five years old, having first entered operational service with the U.S. Air Force back in 1970. (Or, if you wish to nitpick, you could say it’ll be celebrating its fifty-seventh birthday this year, going by the date of the missile’s first test launch on August 16, 1968.)
Back on May 23, 2021, retired U.S. Air Force (USAF) Col. Dana Struckman penned an article for The National Interest titled “Now Is the Time to Replace the Minuteman III ICBM.” Fast-forward to the present day, and the good news for the good colonel and folks who share his viewpoint is that there is finally a replacement nuke being developed, the LGM-35A Sentinel, aka the Ground Based Strategic Deterrent (GBSD). The not-so-good news? There’s a lack of proper silo space for the up-and-coming Sentinels. Er, oops!
Where the Sentinel ICBM Went Wrong
The news of this kiloton kerfuffle comes to us from Defense One staff writer Audrey Stecker in a May 5, 2025, report titled “Sentinel ICBM program needs brand-new silos, Air Force says.” To wit:
“‘The Air Force continues to assess its options and design concepts as part of doing good systems engineering. While no decision has been made, we expect Sentinel to use predominantly [Air Force]-owned real estate to build new missile silos instead of re-using MMIII silos,’ a service spokesperson said in a statement Monday … This shift means the service might have to construct hundreds of new silos, since the Sentinel program is intended to replace 400 aging Minuteman III missiles—spread across missile fields in Colorado, Montana, Nebraska, North Dakota, and Wyoming—on a one-for-one basis. Defense Daily first reported the service would need to build new silos, citing Air Force revelations at town hall discussions in some of those states.”
To add monetary insult to logistical nightmare injury, cost projections of the program have spiraled to nearly $141 billion, thus triggering a breach of the Nunn-McCurdy Act threshold; such a breach kicks in when the program acquisition unit cost or the procurement unit cost increases by at least 15 percent over the current baseline estimate or at least 30 percent over the original baseline estimate.
Stecker concludes her article with a quote from Mackenzie Knight, a senior research associate for the Nuclear Information Project at the Federation of American Scientists:
“I would say, at best it comes down to mismanagement and incompetence, and at worst, an intentional effort to downplay the complexities and challenges of the Sentinel program to make it appear like it would be the cheaper, easier option over just extending the service life of the current force.”
Interestingly enough, back on June 25, 2024, Stecker also reported on the firing of Sentinel Systems director Col. Charles Clegg; however, USAF spokesperson Ann Stefanek stated at the time that Clegg’s removal was “not directly related” to the ballooning cost overruns.
Sentinel vs. Minuteman III: A Quick Comparison
Physical dimensions of the Sentinel have not been made public yet, other than the payload of its warheads: 300 kilotons of TNT for the original variant of the W87 and 475 kilotons of TNT for the W87-1 upgrade.
Meanwhile, the Minuteman III primarily employs the original W87. It also still uses, to a lesser extent, the W78 warhead, which packs a 335-350 kiloton payload. In other words, the older tops off at a mere 73 percent of the newer nuke’s punching power potential. The Minuteman III is 59.9 feet (18.3 meters) in length and 5.5 feet (1.68 meters) in diameter. It would be interesting to see the height and diameter differential in the two missiles and how that factored into the silos’ incompatibility with the newer weapons system.
The Way Forward for the Sentinel ICBM
Housing-related logistical nightmares notwithstanding, development of the Sentinel missiles themselves seems to be proceeding fairly smoothly thus far, more or less. Yet some segments of the program have been paused. The manufacturer, Northrop Grumman, appears optimistic, at least according to its official announcements:
“The U.S. Air Force and Northrop Grumman Corporation completed a full-scale qualification static fire test of the Sentinel intercontinental ballistic missile (ICBM) stage-one solid rocket motor March 6, 2025, at Northrop Grumman’s facility in Promontory, Utah.”
If all goes according to plan, the Sentinel program will go operational in 2030 and extend the capabilities of the land-based leg of the U.S. nuclear triad through 2075.
About the Author: Christian D. Orr
Christian D. Orr was previously a Senior Defense Editor for National Security Journal (NSJ) and 19FortyFive. He is a former Air Force Security Forces officer, Federal law enforcement officer, and private military contractor (with assignments worked in Iraq, the United Arab Emirates, Kosovo, Japan, Germany, and the Pentagon). Chris holds a B.A. in International Relations from the University of Southern California (USC) and an M.A. in Intelligence Studies (concentration in Terrorism Studies) from American Military University (AMU). He has also been published in The Daily Torch, The Journal of Intelligence and Cyber Security, and Simple Flying. Last but not least, he is a Companion of the Order of the Naval Order of the United States (NOUS). If you’d like to pick his brain further, you can ofttimes find him at the Old Virginia Tobacco Company (OVTC) lounge in Manassas, Virginia, partaking of fine stogies and good quality human camaraderie.
Image: DVIDS
