WASHINGTON — The United States Navy’s Strategic Systems Programs (SSP) office, in coordination with the Department of Energy’s National Nuclear Security Administration (NNSA), has formally transitioned the W93 nuclear warhead and its associated Mk7 reentry body into the Engineering and Manufacturing Development (EMD) phase. The program successfully achieved Milestone B approval, marking the transition into full-scale production design and manufacturing qualification for the first entirely new U.S. submarine-launched nuclear weapon program initiated in nearly four decades.
Designed by Los Alamos National Laboratory (LANL), the W93/Mk7 system is engineered to modernize the sea-based leg of the U.S. strategic nuclear triad. The warhead architecture leverages previously tested nuclear components updated with advanced materials, insensitive explosives, and modern safety systems. Once fielded, the W93 will complement and eventually succeed the legacy W76 (Mk4) and W88 (Mk5) warhead inventory aboard Trident II D5 Submarine-Launched Ballistic Missiles (SLBMs).
The Mk7 reentry body architecture also serves as a critical common element for the United Kingdom’s strategic nuclear deterrent. Under a parallel sovereign development initiative designated Project Astraea (A21 warhead), the Royal Navy will integrate the Mk7 aeroshell onto its next-generation Dreadnought-class ballistic missile submarines. Initial operational deployment of the W93/Mk7 system aboard U.S. Navy Ohio-class SSBNs is projected for the mid-2030s, followed by seamless transition onto the incoming Columbia-class SSBN fleet.
TECHNICAL SPECIFICATIONS: W93 NUCLEAR WARHEAD & MK7 REENTRY BODY
* System Designation: W93 Submarine-Launched Ballistic Missile (SLBM) Warhead / Mk7 Reentry Body (Aeroshell)
* Acquisition Phase: Milestone B Passed / Engineering and Manufacturing Development (EMD)
* Primary Managing Agencies: U.S. Navy Strategic Systems Programs (SSP) & National Nuclear Security Administration (NNSA)
* Primary Design Authority: Los Alamos National Laboratory (LANL)
* Missile Integration: Trident II D5, D5 Life Extension (D5LE), and future D5LE2 SLBMs
* Operating Platforms (US Navy): Ohio-class Ballistic Missile Submarines (SSBNs) and Columbia-class SSBNs
* Allied Interoperability (Royal Navy): Mk7 Reentry Body commonality with UK sovereign A21 (Astraea) warhead for Dreadnought-class SSBNs
* Legacy Inventory Target: Supplemental replacement for legacy W76-0/1/2 (1978) and W88 (1988) warheads
* Design & Safety Architecture: Incorporates previously underground-tested nuclear yield components, modern insensitive high explosives (IHE), advanced electronic arming/fuzing architectures, and enhanced safety/security features
* Projected Fleet Introduction: Mid-2030s initial operational deployment aboard sea-based nuclear triad assets
