Pentagon Seeks To Develop New Nuclear Gravity Bomb

The Pentagon wants to build a new nuclear gravity bomb, aiming to modernize part of its strategic stockpile by replacing one of the most potent variants of its B61.

The Defense Department says in an announcement that it wants a modern variant of the B61, to be designated the B61-13, if Congress approves it. The new variant would replace some of the B61-7s in its stockpile while maintaining about the same yield—around 360 kilotons. The bomb would be produced by the Department of Energy’s National Nuclear Security Administration.

“Today’s announcement is reflective of a changing security environment and growing threats from potential adversaries,” Assistant Secretary of Defense for Space Policy John Plumb said in an announcement. “The United States has a responsibility to continue to assess and field the capabilities we need to credibly deter and, if necessary, respond to strategic attacks, and assure our allies.”

The B61-13 would be carried by modern aircraft, including the next-generation B-21 Raider and possibly the B-2A Spirit if it is still in service when the weapon is fielded. The B-2 can carry up to 16 B61-7s.

The new bomb would not be carried by dual-capable fighters, which will be charged to carry the new B61-12.

Pentagon officials point to the Biden administration’s latest Nuclear Posture Review—which outlines that for the first time the U.S. is facing two nuclear peer adversaries in China and Russia—as a reason for a new gravity weapon. It would follow the modernized production process of the new B61-12 and include the modern safety, security and accuracy features of that weapon, the Pentagon says in a fact sheet. That bomb began full-rate production last year.

“The B61-13 represents a reasonable step to manage the challenges of a highly dynamic security environment,” Plumb says. “While it provides us with additional flexibility, production of the B61-13 will not increase the overall number of weapons in our nuclear stockpile.”

The announcement comes as the administration plans to retire the military’s most powerful gravity bomb, the B83.

The Federation of American Scientists (FAS), in an analysis of the announcement, says the B61-13 would use the warhead from the B61-7s and modifications would include a guided tail kit. While the administration’s plan to retire the B83-1 has faced opposition on Capitol Hill, the creation of the new B61-13 could alleviate that and allow for the retirement to continue, FAS argues.