B61 is an air-dropped battlefield/tactical nuclear weapon equipping the F-16 and F-15E in the forward-deployed, allied extended deterrent role. It is also the B-2’s primary strategic weapon.
B61 was first delivered in 1966, and the B61 Mod 11 introduced in 1997 adds a ground-penetrating capability, enhancing its effect against buried and hardened targets. The weapon incorporates several preselectable yield options tailored to mission requirements.
The B61 Mod 12 Life Extension Program (LEP) begun in 2016 is consolidating the B61-3, -4, -7, and -10 into a single, standardized configuration. The LEP refurbishes the warhead to improve the safety, security, and reliability through 2040. B61-12 also adds a guided tail kit, making it the first precision guided weapon of its type, thus permitting higher effectiveness at lower yields.
USAF and the National Nuclear Security Administration finished B61-12 qualification flight-testing on June 9, 2018. The 31 inert test drops greatly exceeded performance requirements, validating nonnuclear components such as arming/fire control, guidance, spin-rocket motors, and software. B61-12 was approved for production and completed operational flight-testing on the F-15E and B-2A in 2019. Operational testing included 15 drops, certifying the F-15E in 2020, as the first aircraft capable of delivering the B61-12.
The Department of Energy conducted nine additional drops, culminating in a full weapon system demo on the B-2A. The F-35A dropped an inert B61-12 for the first time in 2020 and full integration is planned as part of ongoing Block 4 development. The first production B61-12 was produced in 2021 prior to full-rate production ramp-up the following year. The entire inventory is slated for upgrade through FY26.
Congress additionally approved DOD plans to develop a B61-13 variant using -12 enhancement to modernize the higher yield -7 in August 2024. B61-13 will modernize the existing weapons for use against “harder and large area military targets,” replacing the 1.2 megaton B83-1 and the approximately 360 kiloton-yield B61-7 without increasing the existing stockpile.
B61 Thermonuclear Bomb Technical Data
Contractors: Los Alamos National Laboratory (weapon); Boeing (B61- 12 tail kit).
Delivered: 1966.
IOC: 1968.
Production: N/A.
Inventory: Approx. 500.
Operator: AFMC, USAFE.
Deployed Locations: Aviano AB, Italy; Büchel AB, Germany; Ghedi AB, Italy; Incirlik AB, Turkey; Kleine Brogel AB, Belgium; Volkel AB, Netherlands.
Active Variant: •B61. Supersonic-droppable free-fall thermonuclear weapon.
Dimensions: Length 11 ft 8 in., diameter 1 ft 1 in.
Weight: 700 lb; 825 lb (B61-12).
Performance: N/A.
Guidance: None (B61 Mod 1 to 11); unknown, likely INS (B61 Mod 12)
Warhead: One B61 -3, -4, -7, -10, or -11.
Estimated Yield: 0.3 kilotons, 1.5 kilotons, 10 kilotons, 50 kilotons (preselectable).
Integration: B-2A, F-15E, and F-16C/D; NATO: F-16A/B Mid-Life Upgrade (MLU), and Panavia Tornado IDS. Planned: B-21, F-35A.
