WASHINGTON — The U.S. Air Force has dubbed its next-generation intercontinental ballistic missile the LGM-35A Sentinel.

The official name for the United States’ next nuclear missile, which until now has been referred to as the Ground Based Strategic Deterrent, was announced by the service Tuesday.

The Sentinel is to succeed the 5-decade-old Minuteman III beginning in 2029, and it would represent a major upgrade — and a costly one, at $100 billion — to the ICBM portion of the U.S. nuclear triad. Nuclear-armed bombers, such as the B-52 Stratofortress and the in-development B-21 Raider, as well as submarines make up the other two portions of the nuclear triad.

Don Koser, Air Force Global Strike Command’s lead historian, said in a Monday interview that the name was chosen to evoke the image of “one that stands guard and keeps the watch.”

It also is intended to signal the continuation of the vigil carried out by airmen and Air Force civilians who operated, secured, maintained and supported its predecessors: Minuteman, Peacekeeper, Titan and Atlas. The latter is America’s first ICBM system, and it became operational in 1959.

“Our nation’s nuclear deterrent force, two legs of which is operated by airmen, has quietly provided a strategic security shield for decades,” Air Force Secretary Frank Kendall said in a release. “All that time, the Department of the Air Force has kept the watch; always vigilant and ready. The name Sentinel recognizes the mindset that thousands of airmen, past and present, have brought to the deterrence mission, and will serve as a reminder for those who operate, secure, and maintain this system in the future about the discipline and responsibility their duty entails.”

Beginning in the 1950s, the military drew some of its earliest missiles’ names from Greek mythology, resulting in the Atlas and Titan programs, as well as the Nike anti-aircraft missiles. The Navy’s Poseidon and Trident submarine ballistic missiles also followed in the 1970s.

The Air Force shifted gears in the early 1960s and looked to American history for inspiration when it named the first in the series of Minuteman missiles, after the colonial-era militiamen who were ready to rapidly respond to danger at all times. Koser said the Air Force hoped such a name would be more “relatable” to the American public.

In 1986, the Air Force fielded the four-stage Peacekeeper missile, capable of delivering multiple nuclear warheads on different targets using multiple independently targeted reentry vehicles. Those weapons were deactivated in 2005.

When asked why the Air Force opted out of choosing a name from mythology or a specific historical reference, like the Minuteman, Koser said the service considered six factors: historical relevance, the link to the mission, aggressiveness, popularity, simplicity and recognition.

Global Strike Command could not say how many other names were considered, or identify some of the other candidates.

Tom Karako, director of the missile defense project at the Center for Strategic and International Studies, who last year wrote about the need for better names of weapons, said he thinks the metaphor of a sentinel keeping watch is fitting.

“America’s most fearsome weapons need better names,” Karako said. “Bland descriptors, acronyms, and bunches of letters and numbers are good enough for some weapons. But instruments of deterrence, the bedrock of U.S. national security, deserve a proper name, conjuring up story, honor and connection to the past.”

The LGM-30G Minuteman III was first deployed in 1970. There are now about 400 Minuteman IIIs in hardened silos, designed to withstand attacks, spread out across the country at F.E. Warren Air Force Base in Wyoming, Malmstrom Air Force Base in Montana, Minot Air Force Base in North Dakota, and other sites in Colorado and Nebraska.

Launch crews of two officers are on duty around the clock in underground launch control centers, which are connected to the silos with hardened cables and can be contacted immediately by the president or defense secretary.

The Defense Department says the $100 billion Ground Based Strategic Deterrent program is necessary to modernize the ICBM force and maintain an effective deterrent to China and Russia. The department also says the GBSD effort would be about $38 billion cheaper than extending the Minuteman III through 2075.

But critics of GBSD argue the modernization plans are escalatory, excessive for a deterrent capability and wasteful. Some Democratic lawmakers have opposed the program and sought to divert money away from it last year.

Northrop Grumman received a $13.3 billion contract in 2020 to develop the GBSD, and it opened a $1.4 billion facility in Colorado Springs, Colorado, last August to work on it and other strategic weapons programs.

The Air Force said the Sentinel will use a modular architecture that can be easily upgraded with new, emerging technologies to meet evolving threats, and will be easier to maintain than the Minuteman. This will save money and keep the Sentinel relevant well into the 2070s, the service said.

The Air Force’s current missile bases will also be the home of Sentinel missiles. Koser said the Sentinel upgrade will modernize more than the missiles themselves; it will also modernize or replace the existing Minuteman-era silos, control centers and ground infrastructure, as well as its flight systems and command-and-control systems.

The Air Force said that adapting the existing infrastructure will allow both the Minuteman III and the Sentinel to meet all nuclear surety and safety standards during the transition process.

Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.

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