This year, the US Department of Defense (DOD) announced funding for a new ballistic missile program, the main goal of which will be to replace existing Minuteman-III (or LGM-30G) nuclear-capable missiles with modern missiles, such as the new Sentinel (LGM- 35). The seriousness of American plans is evident just by the numbers: the U.S. military plans to allocate a record $140.9 billion for this “missile swap,” and this number will likely grow. The amount earmarked for the program is nearly double the initial budget of the program, which was initially estimated at $95 billion, reflecting the challenges that the U.S. is facing today. Its main strategic rival, China, continues to expand its nuclear arsenal. At the same time, Russia has maintained rough parity with the U.S. in intercontinental ballistic missiles (ICBMs) and nuclear warheads since the end of the Cold War.
Despite the necessity of modernization, however, many military officials and analysts note that the timeline for completing all planned aspects of the program could stretch over several years, potentially causing the U.S. to lag behind other states in the “nuclear club.” The project’s financial aspects have also raised questions. The Government Accountability Office (GAO) has noted that the program’s budget has already grown substantially, potentially jeopardizing funding for space forces, cybersecurity, electronic warfare, and tactical-level ballistic systems, among other things. Here, we analyze the reasons behind the emergence of the new U.S. ballistic program and whether its planned implementation might ultimately weaken U.S. military strength in other areas.
Minuteman-III: A Half-Century Journey
The three-stage nuclear-capable Minuteman-III ICBM was introduced into U.S. service in 1970, at the height of the Cold War. It was the first silo-based intercontinental ballistic missile with a solid-fuel rocket engine in the U.S. armed forces, and it remains so today.
The missile’s capabilities were terrifying—its nuclear warhead was initially designed as a kind of cluster munition: early generations of the Minuteman-III could release up to three nuclear warheads simultaneously. This formed the basis of the then-innovative Multiple Independently Targetable Reentry Vehicle (MIRV) system. As a result, the missile could strike three different targets, and, due to the warheads’ separation during the final stage of flight, intercepting them in the late phases of their approach to the target was nearly impossible.
Early Minuteman-III generations were equipped with W62 nuclear warheads, each with a yield of 170 kilotons. However, as the Minuteman-III aged, the missile underwent numerous modifications, one of which involved the warhead. In 1979, the W62 warhead was replaced with the W78, with a yield of 335-350 kilotons. Then, starting in 2007, the missiles began to be equipped with W87 warheads, which were taken from decommissioned LGM-118A Peacekeeper (MX) missiles. The W87 warheads were newer and more accurate, thanks to their improved guidance system. The operational safety of the new warheads also significantly improved, as did the missile’s targeting system.
Officially, the yield of the W87 was 300 kilotons, but upgrades have increased this to 475 kilotons. Unlike the three warheads of the earlier MIRV system, however, the modern Minuteman-III carries only a single warhead, or Single Reentry Vehicle (SRV). This shift was necessitated by the provisions of the second Strategic Arms Reduction Treaty (START II), which Russia and the U.S. signed in January 1993. Only the U.S. ratified the treaty, however, since the Russian Duma found them disadvantageous. Nevertheless, the transition from three warheads to one was implemented. Thus, current Minuteman-III varieties only use the single-warhead configuration.
The primary advantage of the silo-based Minuteman-III missile was its solid-fuel rocket engine. By the 1950s, engineers recognized that solid rocket fuel had superior long-term storage capabilities compared to liquid propellants. This allowed the Minuteman to be fueled before being loaded into the launch silo, significantly reducing the time required for preparation and subsequent launch (preparing a liquid-fueled missile typically took an additional 30-60 minutes). The use of solid-fuel rocket engines has been a feature of all three generations of the missile, starting with the first Minuteman, which entered service in 1962, and continuing through the latest Minuteman-III modifications.
Over the years, the Minuteman-III missile has undergone several major modernization programs to replace key systems and outdated components. Early versions of the Minuteman-III used an NS20A gyroscopic guidance system, which was replaced by the more advanced NS50A, during the implementation of the Replacement Program, completed in 2008. The NS50A system not only offers greater accuracy but also extends the missile’s service life, allowing the third generation of Minuteman missiles to remain in use through 2030 at least.
Another Minuteman-III modernization, which took place between 1998 and 2009, involved replacing the missile’s boost engines. During this eleven-year upgrade cycle, the solid-fuel boosters used in the first stage of the missile were replaced. The propulsion system for the final stage remained the same, with the RS-14 two-component liquid rocket engine, produced by Rocketdyne being the only remaining liquid-fueled engine.
Although the Minuteman-III was originally designed to be launched from a ground-based silo missile, the accumulation by the Soviet Union of its own nuclear missile stockpiles prompted American military officials to develop auxiliary launch options in case of the destruction of launch silos or ground command centers. This led to the development of the Airborne Launch Control System (ALCS), which allowed for missiles to be fired from specially modified aircraft, including the Boeing EC-135 and, later, the Boeing E-6 Mercury. The Mercury remains a backup launch platform to this day.
During the Cold War, the Minuteman-III arsenal reached 1,000 combat-ready missiles in silos across the United States. However, after the dissolution of the USSR, and in light of the Russian Federation’s continued support for détente, questions arose regarding the possibility of reducing missile stockpiles. The primary factor was cost savings; the disappearance of the Soviet threat made maintaining such a large stockpile of nuclear missiles unnecessary. Consequently, the number of Minuteman-III missiles was reduced by nearly 60% by the turn of the millennium.
New global tensions in recent years have renewed the relevance of Minuteman-III ICBMs, prompting the U.S. to resume test launches of the missile, albeit without warheads. The most recent launch took place from the Space Force base at Vandenberg on June 4, 2024.
Currently, the U.S. has approximately 400 fully upgraded Minuteman-III missiles on continuous alert in missile complexes across the country, operating under the Air Force Global Strike Command. Most of these missiles are located in silos in Montana (Malmstrom AFB), North Dakota (Minot AFB), and Wyoming (F.E. Warren AFB). The total area dedicated to Minuteman-III support infrastructure is about 40,000 square miles (64,000 square kilometers). This area includes not only missile silos but also underground coordination and launch control centers, all connected by a network of deeply buried reinforced cables.
The Minuteman-III remains the only land-based silo missile in the U.S. nuclear triad. The other two components of the triad consist of nuclear warheads delivered by long-range strategic aviation or submarines. The missile’s long service life, however, has inevitably led to discussions about the need to replace the Minuteman-III with a new ground-based missile system.
It was from these discussions that the Ground Based Strategic Deterrent (GBSD) program emerged, which later resulted in the development of the Minuteman-III’s successor, the LGM-35 Sentinel.
LGM-35 Sentinel: Development Launch
Calls for the development of a new ICBM to replace the Minuteman-III began emerging in the mid-2010s. In July 2016, the U.S. Air Force Nuclear Weapons Center formulated its requirements for a new ballistic missile for nuclear deterrence, which ultimately led to the creation of the Ground Based Strategic Deterrent (GBSD) program. Officially approved on July 29, 2016, the plan called for a new ground-based ICBM to begin replacing the Minuteman-III beginning in the 2030s.
The operational lifespan of the new system needed to be similar to that of its predecessor, meaning that the new GBSD should be in service until at least 2075. All of the remaining 400 Minuteman-IIIs are to be replaced by GBSDs, meaning that the new system will not require the production of new nuclear warheads.
By 2017 both Boeing and Northrop Grumman were competing to work on the project and the U.S. Department of Defense awarded contracts worth $329 million and $349 million to each company, respectively. Following this, the firms began developing their respective concepts for the GBSD.
However, while the competition was intense it ended up being short-lived: by 2019, Boeing had announced its withdrawal, leaving Northrop Grumman as the sole contractor. In reality, of course, the company brought in a range of subcontractors to work on the new ICBM, including Lockheed Martin, General Dynamics, Bechtel, Honeywell, Aerojet Rocketdyne, Parsons, Collins Aerospace, and Textron. These subcontractors have been engaged at various stages of the development of the main components of the GBSD, including the launch platform and support infrastructure used for maintaining the new missiles. At the time of Boeing’s withdrawal from the program in 2019, its budget was estimated at $60 billion.
In 2020, the Pentagon awarded Northrop Grumman a second contract, this time worth $13.3 billion, marking the official start of the development of the GBSD as we know it today. In April 2022, the future missile was officially named the LGM-35 Sentinel.
One of the main differences between the Sentinel and the Minuteman-III is the missile’s nose cone. While on the Minuteman-III this component was made of steel, Northrop Grumman plans to replace it with one made from carbon composite materials, meaning that the new missile will likely incorporate 3D printing and modular assembly.
In 2021, Northrop Grumman opened a new facility in Huntsville, Alabama and expanded its workforce to 2,000 employees. The new Atlanta division focused on developing a signal intelligence (SIGINT) sensor for high-altitude surveillance and reconnaissance platforms. One key requirement was the use of open-standards communication software. The new type of sensor was intended for use in the Global High-altitude Open-System Sensor Technology (GHOST) for the Air Force, but the system was also relevant for the Sentinel since the missile will operate in conjunction with orbital missile launch monitoring systems. The contract for developing GHOST was awarded to Northrop Grumman in October 2021.
New production cycle and current issues
The choice to use new carbon polymers for the Sentinel’s fuselage is expected to reduce not only the missile’s weight but also its production cost by simplifying the manufacturing cycle. This concept seems promising on paper, but recent years have indicated that rising inflation may affect this plan. The estimated cost of a Sentinel missile, forecast at $118 million apiece in 2020, was projected to rise to $162 million over the next four years. Moreover, this is not taking into account that 6 years remain before the new ICBM ever enters production: Northrop Grumman initially promised to start delivering missiles in 2029, but this timeline has been pushed back by one year. As a consequence, the cost of each missile is expected to increase further.
Many of these cost increases and production delays can be attributed to new challenges related to cybersecurity, a result of the missile’s software architecture. The requirement to use open communication standards and standardized protocols has made cyber attacks on the missile easier. New software that was intended to speed up and simplify control and interaction has also become a major issue. Other factors contributing to development delays have been a shortage of qualified personnel and disruptions in supply chains for sensitive missile components.
Since the Pentagon requires the new missile system to have a minimum operational lifespan of fifty years, the Sentinel will likely have a series of phased upgrades throughout its lifecycle due to the emergence of new technologies. Nuclear deterrence remains the top priority and underpins all other branches of the military. Today, no global military operations are planned without considering U.S. nuclear deterrence.
Another benefit of the Sentinel’s reduced launch mass is its increased payload capacity, which in the context of ICBMs means the ability to carry more nuclear warheads. Moscow’s exit from the last START treaty in 2023 means that the U.S. is no longer constrained in the development of its own nuclear missiles. This means that it is possible that the Sentinel could see the return of features similar to the Minuteman-III’s previous MIRV capabilities.
The Sentinel is also expected to feature a hybrid guidance system: in addition to standard GPS positioning, it will incorporate an astro-inertial guidance system to provide correction assistance during the missile’s final flight stages. Currently, the Sentinel is planned to be equipped with the latest “Mod0” and “Mod1” M87 warheads, but the U.S. Air Force is already considering how to replace these aging weapons with newer, more effective, alternatives.
So, when serial production of the missile begins in 2030, its warhead may already be different – provided, of course, that it fits within the already inflated budget of the new missile program.
How exhausting might the new missile race become?
Regarding the overall need for a modernization of the ground segment of America’s nuclear deterrence forces, it is worth looking back at previous eras. One of the earliest, and perhaps most (in)famous, American ballistic missile programs was the Strategic Defense Initiative (SDI), or “Star Wars,” which was approved by Ronald Reagan in 1983.
SDI aimed to develop new methods of missile defense to prevent a potential Soviet nuclear strike. The initiative was intended to create a multi-layered system for detecting, tracking, and intercepting ballistic missiles. This structure required the coordination of various assets, from satellite operators monitoring missile launches to ballistic missile interceptor forces. However, by the early 1990s, SDI was somewhat redundant: the USSR had collapsed, and the new Russian leadership showed a willingness to sign the new START II treaty, putting an end to the nuclear confrontations of the past once and for all.
Ultimately, however, START II did not stand the test of time because Moscow did not want to ratify the agreement, even though the United States did so shortly after signing. Initially, the Strategic Offensive Reductions Treaty (SORT) replaced START II. SORT was itself superseded by the new START III treaty. In the end, though, none of these treaties ended up being worth the paper they were written on.
As for SDI, the program was first reorganized into the Ballistic Missile Defense Organization under President Bill Clinton and later transformed into the Missile Defense Agency (MDA) under President George W. Bush. Nevertheless, the Strategic Defense Initiative laid the groundwork for many innovations in missile and space defense, which the Pentagon continues to use today.
When considering the actual threat to the U.S., the modernization of its missile forces is partly driven by the capabilities of its strategic rivals. China possesses a three-stage solid-fuel ICBM, the Dongfeng-41, with a range of 11,000 km, and Russia has its two-stage R-36M (also known as the SS-18), which uses a more complex and demanding liquid engine but which has a larger range (16,000 km). These ground-based ICBMs remain the main rivals of the Minuteman-III.
Everything indicates that modernizing ballistic missiles is now an integral part of the current arms race. As we can see, the Department of Defense is sparing no expense. Indeed, the high cost of developing and manufacturing new missiles could become the Achilles’ heel of American missile rearmament.
Ever-growing multibillion-dollar defense budgets can be exhausting for the economy of any country and the global arms race is, above all, a war between the economic and industrial capacities of major rivals. During the last Cold War, it was the Soviet economy that could not ultimately withstand this burden. But the past is not necessarily a guide for the future. Thus, the production of hundreds of missiles that will likely remain in their silos for the next 50 years could very well become a heavy burden on the American budget in the coming years.
The costs of modernization are especially apparent when considering that the previous decade of modernizing the fairly effective Minuteman-III missiles cost the military administration only $7 billion. By contrast, the Sentinel program, even before its official start, has required nearly $160 billion from the national budget over just 6 years. As we have seen, there are other issues currently affecting the Sentinel program. Resolving these problems risks extending the timeline by years, further delaying the delivery of new missiles and potentially increasing the program’s overall budget impact even more.
One alternative to solid-fueled intercontinental ballistic missiles is the use of non-nuclear tactical cruise missiles, which remain impactful at the operational-tactical level in actual combat conditions. The effectiveness and high demand for solid-fueled tactical missiles have been demonstrated by the current conflict in Ukraine, where the Ukrainian military has been showcasing their use for three years. You can read more about the development of American short- and medium-range ballistic missiles in upcoming articles.
