When the Ground Based Strategic Deterrent (GBSD) arrives to replace the Minuteman III silo-based intercontinental ballistic missiles, the Minuteman III’s old nuclear warheads might go right back into the ground on the new missiles, a senior National Nuclear Security Administration (NNSA) official said Wednesday.

The next-gen missiles will use about a 50-50 mix of old W87-0 warheads, those on Minuteman III today, and planned W87-1 warheads, which will be based on the W87-0 design, but use brand new plutonium pits. The new warheads will replace the W78 warheads used on Minuteman III.

The NNSA plans to start casting new W87-1 pits at Los Alamos National Laboratory in 2024. The first war-ready version of the new warhead, called by NNSA the first production unit, would notionaly be ready in 2030, according to the agency’s Stockpile Stewardship and Management Plan.

But the W87-0 could be certified to tip the GBSD in the mid- or late-2020s, Charles Verdon, NNSA’s deputy administrator for defense programs, told reporters here after a hearing of the House Appropriations energy and water subcommittee.

“The way it’s planned, it may be that we’re putting on 87-0s on first but then quickly rolling on the 87-1s,” Verdon said.

Certifying the old W87-0s on GBSD would involve flying non-nuclear dummy versions of the warhead on the new missile. The Air Force has said it will award the roughly $25 billion contract to build the solid-fueled GBSD missiles between July and September of this year, and Northrop Grumman [NOC] looks all but certain to get the work.

Early use of W87-0 short circuits a scenario in which the brand new GBSD missiles — designed to remain in service into the 2080s — are ready to sink into silos before their planned warheads.

The NNSA faces tremendous pressure to get its planned pit complex up and running. The 10 W87-1 pits a year planned at Los Alamos will tax the laboratory’s personnel and infrastructure, even after planned upgrades — and those pits are only the beginning of the NNSA’s plans.

To outfit a planned GBSD fleet of 400 missiles (the Air Force will procure more than 600 GBSD missiles in total, including spares and test articles) the NNSA plans to build a brand new pit factory at the Savannah River Site in Aiken, S.C., where, by 2030, the agency plans to cast 50 pits annually.

NNSA expects the pit complex to cost $30 billion to build and operate for a few decades. The requested 2021 budget for those factories is $1.4 billion, up from about $800 million for 2020. Between Savannah River and Los Alamos, the NNSA’s goal is 80 pits a year by the dawn of the next decade. Los Alamos is slated to ramp up to 30 annually by 2026.

It is a tall order, which the NNSA admits, and while Verdon said the W87-0 was not a hedge against the long odds of getting a split-state pit complex up and running in 10 years, the weapons boss allowed that the two planned GBSD warheads “hedge themselves.”