According to a recently declassified report, the National Nuclear Security Administration (NNSA) thinks it will cost some $14.8 billion to build W87-1 warheads for the Ground Based Strategic Deterrent (GBSD) missiles planned to replace Minuteman III as the land-based leg of the nuclear triad starting around 2030. 

That could make W87-1 — a newly manufactured copy of the existing W87 design, but with a brand new plutonium-pit trigger — “the most expensive program of this type to date,” the Government Accountability Office (GAO) wrote in a summary of its report.

Speaking of the pits, which begin a weapon’s nuclear chain-reaction, GAO also wrote that it’s unclear if the NNSA “can produce enough of the W87-1’s fissile cores in time to meet its planned production schedule.”

The NNSA has said it is working on a W87-0 warhead that could tip initial GBSD missiles if the W87-1 is not done in time to be installed aboard the first of the next-generation, silo-based weapons. Northrop Grumman [NOC] will build the new missiles, under a roughly nine-year, $13 billion Air Force contract. The Air Force plans to buy more than 650 of the missiles but currently plans to deploy about 400: the same number of Minuteman III missiles now in service.

W87-0 refers to existing W87 warheads, which are used today throughout the Minuteman III fleet, a senior NNSA official told Defense Daily affiliate publication Weapons Complex Monitor earlier this year. The new warhead iteration would need flight testing before it could be cleared for use on the new missiles, the official said.

The NNSA plans to start casting new war-ready, W87-1 plutonium pits at the Los Alamos National Laboratory in 2024. Those planned warheads will replace the current W78 models.

GAO released its latest NNSA report for limited distribution on Sept. 9, then released the report publicly Wednesday morning.