The W76 and W88, the two types of nuclear warheads that can be launched on missiles from Ohio-class submarines, were both designed at Los Alamos National Laboratory. In the decades since, they’ve also been maintained primarily by Los Alamos through life extension programs (LEPs), modifications (Mods), and alterations (Alts).
LEPs address aging and performance issues, enhance safety features, and improve security. Through an LEP, scientists and engineers analyze a weapon’s components and, based on that analysis, reuse, refurbish, or replace certain components.
Completed in January 2019, the W76-1 LEP was a refurbishment of the W76-0 warhead, which entered the stockpile in 1978. The LEP extended the warhead’s service life from 20 to 60 years. The W76-1 continues to meet all missions and capabilities of the original W76-0 warhead but does not provide new military capabilities.
Modifications change a weapon’s operational capabilities. A modification may enhance the margin against failure, increase safety, improve security, replace limited-life components, or address identified defects and component obsolescence.
The W76-2 Mod, a Los Alamos program, is a modification of the W76-1 warhead. The W76-1 produces a high nuclear yield; the W76-2 provides a low-yield, sea-launched ballistic missile warhead capability. The first W76-2 was produced on February 22, 2019, at the Pantex Plant in Amarillo, Texas.
W88 Alt 370
Alterations are changes to a weapon’s systems, subsystems, or components. Not as extensive as an LEP, an alteration is a limited-scope change that affects the assembly, maintenance, and/or storage of a weapon. The alteration may address identified defects and component obsolescence without changing a weapon’s operational capabilities.
The W88 nuclear warhead entered the stockpile in 1988. Deployed now for more than 30 years, the warhead requires several updates to address aging issues and to maintain its current state of readiness. Started in 2012, the W88 Alt 370 program replaces the arming, fuzing, and firing subsystem, adds a lightning arrestor connector, and refreshes the weapon’s conventional high explosives to enhance nuclear safety and support future LEP options. The first production unit was delivered in July 2021.