The W93 SLBM Warhead Will Deter America And Britain's Enemies

United States Trident II (D-5) missile underwater launch. U.S. Navy.
May 17, 2020 Topic: Security Region: Americas Blog Brand: The Reboot Tags: Nuclear WeaponsW93Nuclear TriadSLBMDeterrence

The W93 SLBM Warhead Will Deter America And Britain's Enemies

The requirement to maintain a safe, secure and effective arsenal includes a modern and functioning nuclear weapons complex.


In his 2009 Prague speech, President Obama declared that "As long as [nuclear]weapons exist, the United States will maintain a safe, secure and effective arsenal to deter any adversary, and guarantee that defense to our allies.”  To ensure that goal, he advanced a modernization program for America’s aging nuclear forces.  President Trump, in his 2018 review of U.S. nuclear posture, reaffirmed that commitment and carried forward the program for force modernization that now will include a new program for a modern SLBM warhead—the so-called W93 to be carried in a new Mark 7 reentry vehicle.

The requirement to maintain a safe, secure and effective arsenal is often taken to mean the replacement of America’s aging strategic triad forces and their command and control.  That effort, while truly vital, is only half what is needed.  The other half is to have a modern and functioning nuclear weapons complex.  This task involves repairs to the facilities which make up the complex, a significant portion of which date back to the Manhattan Project and early Cold War periods; it involves regaining capabilities we have allowed to lapse, such as the ability to manufacture so-called "war-reserve" pits for nuclear warheads; finally, it involves refreshing the scientific and engineering prowess of the DoD and DoE in order to be able to design, when needed, modern nuclear warheads and the reentry vehicles which carry them.  The United States has not designed and developed a modern nuclear warhead or fielded a new reentry system in over thirty five years (since Ronald Reagan was President).  The scientists and engineers who performed this all important work are nearly all retired, and some are no longer with us.  Before the surviving veterans finally pass from the scene, it is absolutely essential that a new generation of scientists and engineers become proficient in continuing this legacy.


The 2021 President’s budget requests funding, among other things, for beginning initial design feasibility work on the W93 and Mark 7 reentry vehicle.   If authorized and funded by Congress, the W93 design will be based on previously tested nuclear designs and will not require additional nuclear explosive testing to certify its safety and reliability.  It will draw from extensive stockpile component and material experience.  The W93 program proposes to incorporate modern technologies to improve safety, security, and flexibility to address future threats—and be designed for ease of manufacturing, maintenance, and certification.  In addition to that, the W93 program supports other critically important national security goals:

  • The Energy and Defense portions of the W93/Mark 7 design and development program provide the much-needed opportunity for DoD and DOE weapons scientists and engineers to regain essential skill sets necessary for future U.S. security.
  • A W93, if developed and deployed in the late 2030s, will be an important addition to the U.S. SSBN force, which forms the backbone of our strategic nuclear deterrent. The current force carries a disproportionate mix of W76 and W88 warheads (because W88 production was halted at the end of the Cold War, the mix is inordinately dependent on the W76; any problem with that warhead would have major implications for the overall U.S. deterrent).  These two warheads provide almost 60 percent of the total U.S. deployed nuclear deterrent.  This is an area where we can least afford to take risk.  The W76 has just completed a life extension program; the W88 is undergoing limited modernization (less than a full scale life extension).  By the time the W93 is deployed, both warheads will have been in service for nearly half a century.   Adding a third warhead in the form of the W93 will hedge against inherent technical risks to those warheads—and reduce current over-reliance on the W76.  Beginning initial design feasibility work now will ensure NNSA is ready for the major design effort once current life extension programs are completed.  Ultimately, depending on future U.S. deterrent requirements and the health of its predecessors, a W93 could replace either the W76 or the W88.  In this context, it is important to note that the W93 is not intended to increase the number of deployed US SLBM warheads:  if designed and built, it would replace existing W76s or W88s on a one-for-one basis, thereby supporting existing and future arms control efforts.  Indeed, the improved reliability of Columbia will allow a significant reduction from the 280 SLBM launchers on the Ohio class to a total of 192 launchers on the Columbia 
  • There is a third critically important but not well recognized reason for proceeding now with the W93/Mark7. It is vital for continuing our longstanding support to the United Kingdom, which is also modernizing its nuclear forces. As an allied but independent nuclear power that contributes to NATO's nuclear deterrence posture, the U.K.'s continuous at-sea nuclear deterrent is critical to U.S. and allied security.  The United Kingdom is currently engaged in modernizing its nuclear deterrent force, building four new SSBNs (elements of which, including the missile compartment and radio room, are being designed jointly with the new US Columbia class SSBN).  Replacing the U.K.'s current nuclear warhead and reentry vehicle is a key part of their modernization effort.  While the design and manufacture of the U.K.'s future warhead will be solely a U.K. responsibility, that program, building on decades of British-American cooperation on the nuclear deterrent, will rely on the U.K.'s ability to procure non-nuclear components – including the reentry vehicle—from the U.S.  As the Trident II/D-5 SLBM remains central to both nations' SSBN forces, parallel U.S. and U.K. warhead and reentry vehicle development programs benefit both of our deterrents. Given the time it takes to design, develop, certify and manufacture a replacement warhead and reentry vehicle, it is important that both nations start detailed design options work now. British Defence Secretary Ben Wallace has noted that Congressional support of the F.Y. 2021 W93 budget requests is "critical to the success of {the U.K.] replacement warhead program and to the long-term viability of the U.K.'s nuclear deterrent and therefore, the future of NATO as a nuclear alliance."

Amidst the understandable public and media focus today on the COVID crisis, the modernization of our nuclear deterrent is rarely discussed.  The need for that will exist long after COVID is behind us.  Russia and China and North Korea have increased their reliance on nuclear weapons.  Returning to Mr. Obama's pledge, the United States must have a safe, secure, and effective nuclear deterrent.  So, too, must our closest ally.  As our two nations' deterrents are modernized, the W93 program will be a necessary element.

Linton F. Brooks, John R. Harvey, and Franklin C. Miller have among them over a century of experience serving in senior posts in the U.S. government overseeing nuclear weapons policies and programs:  Brooks in the Departments of State, Defense and Energy and the National Security Council Staff, Harvey in the Departments of Defense and Energy and Miller in the Department of Defense and the National Security Council Staff.

This article by Linton F. Brooks, John R. Harvey, and Franklin C. Miller first appeared in Real Clear Defense on May 12, 2020.

Image: United States Trident II (D-5) missile underwater launch. U.S. Navy.