The B61 gravity nuclear bomb forms the cornerstone of United States air-delivered deterrent capability. The B61 is the longest-serving and most versatile weapon contributing to the aircraft component of the U.S. nuclear triad. This versatile weapon can be integrated with a variety of aircraft providing unique and tailorable military options to the national command authority.

Decades of B61 design and qualification data gave the Air Force Nuclear Weapons Center and the National Nuclear Security Agency program managers confidence that engineers from nuclear security enterprise design and production agencies could extend and enhance the service life of the B61 weapon systems. The current B61 series is the result of Life Extension Program activities intended to refurbish, reuse or replace the bomb's nuclear and non-nuclear components. LEPs extended the B61 service life by decades. 

Currently, B61 weapons are fielded in two variants: the B61-12 and B61-13. The B61-12 is the linchpin of NATO's nuclear sharing program since it can be integrated with and employed by some allied aircraft.

B61-12 gravity bomb

During the B61-12 Life Extension Program, the Department of Energy’s National Nuclear Security Administration was responsible for the B61-12 nuclear bomb assembly, and the Air Force was responsible for the B61-12 Tailkit Assembly. The B61-12 can be carried and delivered by various fighter and bomber aircraft providing flexible employment options for weapon planners and the national command authority. The B61-12 incorporates enhanced safety and security features consistent with deployment and employment options available to global warfighters.

B61-13 gravity bomb

The B61-13 will strengthen deterrence by providing the president with additional options against certain harder and large-area military targets. The B61-13 will retain the B61-12’s modern safety, security and accuracy features but will have a higher yield.  B61-12 production was truncated to ensure the B61-13 will not increase the overall stockpile numbers.

The B61-13 modification used proven production capabilities that supported the B61-12; this efficiency greatly accelerated the schedule, yielding the first production unit in May 2025. To meet nuclear certification requirements, engineers conduct “design gates,” which are the rigorous reviews conducted at each step of a weapon design process.  Based on significant B61 data and experience, National Laboratory technical teams were able to streamline or combine design gates and commence production earlier than a standard schedule would allow. These practices allowed B61-13 hardware to be manufactured just three months after the program received authorization and appropriation from Congress.