The B61-13 marks an important step toward the modernization of US nuclear forces, combining high-yield capabilities and advanced safety features.
In a bit of good news, the B61-13 nuclear gravity bomb was completed this month, as Christian D. Orr reported earlier this week in these pages. This represents a significant development in the United States’ nuclear modernization efforts—and marks the first time in living memory that the Pentagon has completed anything ahead of schedule!
As the latest variant in the B61 family of air-launched thermonuclear bombs, the B61-13 is designed to restore—and enhance—America’s deterrence against hardened and large-area military targets, while leveraging advanced safety, security, and accuracy features. It is no small feat that this bomb was completed ahead of schedule, given the problems endemic in the US defense industrial base.
America’s B61 family of nuclear bombs, first put into service back in 1968, remains the longest-serving and most versatile weapon in the entirety of the American nuclear weapons arsenal. With over 50 years of service, the B61 series has evolved through 13 variants (Mods 0-to-12), each incorporating advancements in yield options, safety features, and delivery methods.
Why the Pentagon Wanted the B61-13
The B61-13 emerged as a direct response to evolving security threats identified in the 2022 Nuclear Posture Review, which emphasized the need for flexible nuclear options to counter hardened and deeply buried targets, such as underground command and control facilities.
Development of the B61-13 was authorized in 2023, pending Congressional approval and appropriation. The program leveraged the established production capabilities of the B61-12 Life Extension Program (LEP), completed in December 2024 at a cost of approximately $9 billion.
By utilizing existing B61-7 warheads and incorporating modern safety and accuracy enhancements from the Mod 12, the National Nuclear Security Administration (NNSA) accelerated production, completing the first B61-13 unit at the Pantex Plant in Amarillo, Texas, nearly a year ahead of schedule on May 19 of this year. This rapid timeline, unprecedented since the end of the Cold War, was achieved by streamlining design reviews and using decades of B61 design data to minimize risks. Future Pentagon development programs must carefully study the B61-13 development program and emulate it forthwith.
The B61-13 is a “dial-a-yield” thermonuclear gravity bomb, meaning its explosive yield can be calibrated to suit specific mission requirements. The B61-13 is expected to have a maximum yield of around 360 kilotons—roughly 25 times more powerful than the “Little Boy” atomic bomb dropped on Hiroshima in 1945. The older B61-7 nuclear warhead, upon which the B61-13’s warhead is based, had a similar maximum yield.
America’s new B61-13 mirrors the B61-12’s dimensions and features a streamlined casing capable of withstanding supersonic flight and is equipped with a guided tail kit assembly (TKA) that enhances accuracy significantly over earlier unguided versions such as the B61-7. The TKA, developed by Boeing, includes an inertial navigation system (INS) and maneuverable fins, providing limited standoff capability and enabling precise strikes.
The B61-13 is a Full Fuzing Option (FUFO) weapon, supporting multiple detonation modes: air burst, ground burst, free-fall, retarded free-fall, and laydown delivery. Unlike the B61-11, a specialized earth-penetrating variant, the B61-13 is not optimized for deep bunker-busting but can still engage hardened targets due to its high yield and improved accuracy. It is designed for delivery exclusively by strategic bombers, such as the B-2 Spirit and the forthcoming B-21 Raider, and will be deployed from bases in the continental United States.
Understanding the New B61-13
Developed to provide the American president with “additional options against certain harder and large-area military targets,” according to the Pentagon, the bomb’s enhanced accuracy and yield allow it to focus explosive forces more effectively, reducing the need for larger megaton-class weapons such as the B83-1. Sorry, Major Kong.
It is unfortunate we live in a world and a time when nuclear weapons modernization is again at the forefront of the national security discussion. Yet it is a necessary evil, as America’s enemies rapidly build up their own nuclear weapons capabilities.
The B61-13 marks an important step toward the much-needed modernization of US nuclear forces, combining high-yield capabilities and advanced safety features. These weapons should enhance deterrence against America’s enemies.
About the Author: Brandon J. Weichert
Brandon J. Weichert, a Senior National Security Editor at The National Interest as well as a contributor at Popular Mechanics, who consults regularly with various government institutions and private organizations on geopolitical issues. Weichert’s writings have appeared in multiple publications, including the Washington Times, National Review, The American Spectator, MSN, the Asia Times, and countless others. His books include Winning Space: How America Remains a Superpower, Biohacked: China’s Race to Control Life, and The Shadow War: Iran’s Quest for Supremacy. His newest book, A Disaster of Our Own Making: How the West Lost Ukraine is available for purchase wherever books are sold. He can be followed via Twitter @WeTheBrandon.
Image: Wikimedia Commons.
