Late last week, the National Nuclear Security Administration (NNSA) and the U.S. Air Force announced two successful “end to end” non-nuclear system qualification flight tests aboard B-2 Spirits for the newest nuclear bomb to enter into the American arsenal, the B61-12 gravity bomb.

These tests are intended to determine how effectively the bombs can be loaded onto aircraft and deployed using existing methodologies and procedures. Incorporating this new bomb design into existing processes is important for multiple reasons: specialized training for specific weapons systems would dramatically increase the overall cost of the platform’s introduction, and because the B61-12 gravity bomb is slated to slowly replace America’s existing stockpile of B61 nuclear bomb variants, it’s important that the new bombs blend seamlessly into the force. It will take time to transition the old platforms into new ones, and in the meantime, the whole family of B61 bombs needs to be able to play well with one another.

“These qualification flight tests demonstrate the B61-12 design meets system requirements and illustrate the continued progress of the B61-12 life extension program to meet national security requirements” said Brig. Gen. Michael Lutton, NNSA’s Principal Assistant Deputy Administrator for Military Application. “The achievement is also a testament to the dedication of our workforce and the enduring partnership between NNSA and the U.S. Air Force.”

The non-nuclear tests involved dropping the new bomb platform from America’s heavy payload stealth bomber, the B-2 Spirit. The bomb itself, comprised of a NNSA main assembly and a U.S Air Force tail kit for stability throughout the fall, involved the full suite procedures required for a tactical nuclear strike — from mounting the weapon in the bomber’s internal weapons bay to discharging it over the target zone at the Tonopah Test Range in Nevada. The B-2 involved in the June 9th test hailed from the 419th Test & Evaluation Squadron out of Edwards Air Force Base in California.

Despite rising concerns about the growing expense related to the B61-12 program, these new platforms are expected to enter service within the next two years, phasing out existing B61-3, -4, -7, and -10 bombs by 2025. The last legacy bombs to remain in the arsenal will be the B83-1 and B61-11 gravity bomb, both of which possess superior penetration capabilities intended to access and destroy bunkers and other underground facilities.

“The B83-1 and B61-11 gravity bombs can hold at risk a variety of protected targets,” reads the 2018 latest Nuclear Posture Review. “As a result, both will be retained in the stockpile, at least until there is sufficient confidence in the B61-12 gravity bomb that will be available in 2020.”

The real question is, what role would such a nuclear bomb play in future conflicts and just how powerful is it?

Neither answer is particularly easy to come by. The U.S. government has been tight lipped about the payload capacity of the new B61-12, but then, pinning a specific figure to the weapon may not be appropriate. While it appears the weapon will have a maximum yield of 50 kilotons, it seems likely that it will offer the ability to choose the yield of the detonation, limiting the nuclear reaction that takes place within the warhead based on circumstance.