What Is the Minuteman III Missile? All About the US ICBM Just Launched | TDG Explainer

The United States test-launched an unarmed Minuteman III intercontinental ballistic missile (ICBM) in a successful test launch from Vandenberg Space Force Base, California, during the early morning hours of May 21, 2025. The launch, conducted at 12:01 am Pacific Time, was made by a combined crew under the Air Force Global Strike Command.

The test is part of an extended series of regular launch exercises intended to confirm the reliability and viability of the U.S. nuclear deterrence triad. The test also follows as the military prepares for the deployment of the LGM-35A Sentinel, the Minuteman’s future replacement.

Missile Flies Over 4,200 Miles in Routine Operation

Target in the Marshall Islands

The unarmed Minuteman III, which carried a high-fidelity Mark-21 reentry vehicle, traveled approximately 4,200 miles before arriving at the Ronald Reagan Ballistic Missile Defence Test Site on the Kwajalein Atoll in the Republic of the Marshall Islands.

US General Thomas Bussiere, the Air Force Global Strike Command commander, highlighted the strategic importance of the launch: “Today’s ICBM test launch demonstrates the nation’s nuclear deterrent strength and the credibility of the ICBM leg of the triad.”

He also thanked the servicemen involved:

“This formidable protection is sustained by committed Airmen – missileers, defenders, helicopter pilots and the units that support them – who guarantee the nation’s and its allies’ security.”

Authorities made it clear that such tests are routine operations and have nothing to do with global events in the present.

Capabilities and Legacy of the Minuteman III

Key facts about the missile system

First introduced in the early 1970s, the LGM-30G Minuteman III is the sole operational land-based ICBM in the U.S. nuclear triad. Originally up to three nuclear warheads, under arms reduction treaties it now has one warhead per missile.

The missile has a three-stage, solid-fueled propulsion system that facilitates quick readiness for launch and low maintenance. It measures 18.2 meters in height and more than 34,000 kg in weight, and its range is around 13,000 kilometers. Its reentry vehicles are equipped with an advanced inertial navigation system that can strike targets with 120-meter precision.

Minuteman III missiles are housed in hardened underground silos, monitored 24/7 by dual-officer crews and linked to airborne command systems such as the E-6B, which ensures communication even if ground systems are compromised.

Vandenberg and Reagan Sites Play Critical Role

Test overseen by elite units

The test was overseen by the 377th Test and Evaluation Group, the lone ICBM test-specific unit within the U.S. Colonel Dustin Harmon, the unit commander, stated: “Minuteman III continues to be the foundation of America’s strategic deterrent and the unshakeable commitment of the Airmen who prepare it for flight are a testment to its inherent deadliness.”

Confirmation of the test came from missile wings based at F.E. Warren Air Force Base (Wyoming) and Malmstrom Air Force Base (Montana), whose crews contributed vital maintenance and technical guidance.

Terminal end, Reagan Test Site staff gathered telemetry, radar, and optical data to measure the performance of the missile. U.S. Army Lt. Col. Casey Rumfelt wrote: “Reagan Test Site is a vital national resource, uniquely positioned to accommodate vital tests of our nation’s offensive and defensive systems, including all Glory Trip missions.”

Minuteman III to be Replaced by Sentinel ICBM

Next-generation deterrent on the horizon

The Minuteman III, together with submarine-based Trident II missiles and air-dropped nuclear bombs, constitutes the U.S. nuclear triad. Nevertheless, after serving for over five decades, it is going to be replaced with the LGM-35A Sentinel in the Ground-Based Strategic Deterrent (GBSD) program.

The Sentinel will achieve initial operational capability in 2029, with complete deployment into the 2030s. The Air Force has spent close to $7 billion from 2002 to 2012 modernizing the Minuteman III to make it last through 2030.

Today, the U.S. has around 450 Minuteman III missiles stationed in North Dakota, Montana, and Wyoming. Col. Harmon underscored the significance of existing Airmen in building the future: “As we move forward, these same Airmen are charting the course for the Sentinel ICBM, assuring a smooth transition to this next-generation capability and ongoing security for our nation.”

Legacy of the Minuteman Series

Cold War toughness to contemporary deterrence

The Minuteman series was born in the 1950s and changed the face of nuclear preparedness with solid-fuel technology, providing near-instant launch readiness versus earlier liquid-fuel systems.

The first Minuteman was introduced in 1962, and its mission during the decades changed from general deterrence to hard-target capabilities against hardened military targets. The Minuteman III replaced the LGM-118 Peacekeeper when it was retired in 2005, becoming the only land-based U.S. ICBM.

Moreover, the U.S. Strategic Command continues to gather information from every test launch, thereby contributing to ongoing system modernization and deterrence planning. Although arms control agreements currently constrain its warhead potential, the missile remains flexible enough to accommodate future strategic changes.