U.S. Navy Advances First New Nuclear Warhead Programme In Nearly 4 Decades

The US Navy has moved its W93/Mk7 nuclear warhead programme into the Engineering and Manufacturing Development (EMD) phase.

The programme passed Milestone B earlier this year. The next step is to finish the production design and show that the system can be manufactured as required by the Navy.

The Navy announced the move on September 24. It has not given a production schedule, cost estimate or date for when the W93/Mk7 could be deployed.

The Navy said the W93/Mk7 is the first US nuclear warhead and reentry system programme started in nearly four decades.

The programme is being managed by the Navy’s Portfolio Acquisition Executive Strategic Systems Programs (PAE SSP), working with the National Nuclear Security Administration (NNSA) and industry partners.

Milestone B is an acquisition milestone that allows a programme to enter the Engineering and Manufacturing Development stage.

For the W93/Mk7, the work will now focus on finishing the production design and proving that the design can be manufactured.

Vice Adm. Douglas Williams, director of PAE SSP, said the W93/Mk7 is intended to give the Navy flexibility and adaptability for future warfighter requirements. He also said the programme will support an uninterrupted at-sea deterrent.

Williams credited PAE SSP, the NNSA and industry partners for helping move the programme into the next phase.

The programme is being developed with the NNSA and associated national laboratories under the interagency Nuclear Weapons Life Cycle process. The work covers design, development and production.

W93 Will Be Used With Trident II D5

The W93/Mk7 is being developed for the US Navy’s Trident II D5 submarine-launched ballistic missile system.

The Trident II D5 currently carries the Navy’s W76 and W88 nuclear warheads. The warheads are housed inside reentry bodies.

The Navy’s future D5 Life Extension 2 (D5LE2) system will incorporate the W93/Mk7 alongside the existing W76 and W88 families.

The last new US nuclear warhead to enter the stockpile was the W88 in 1988. It is deployed with the Trident II D5 system and has since gone through the W88 Alt 370 modernisation programme.

The W93/Mk7 is therefore part of a new effort to develop a nuclear warhead and reentry system for the Navy’s submarine-launched ballistic missile force.

What Are The W93 And Mk7?

The W93 is the nuclear warhead. It contains the nuclear explosive that produces the nuclear explosion when it reaches its target.

The Mk7 is the reentry body. It carries and protects the warhead during the missile’s return towards Earth.

A ballistic missile can travel outside the atmosphere before coming back towards Earth. During reentry, the vehicle faces very high temperatures and pressure. The reentry body protects the warhead during this part of the flight.

The Navy has not released detailed technical specifications for the W93 or Mk7.

How The W93 Will Be Used?

The W93/Mk7 is being developed for the Trident II D5 missile system.

The future D5 Life Extension 2 system will use the W93/Mk7 alongside the existing W76 and W88 warhead families.

The Trident II D5 is a multiple-warhead missile. A single missile can release more than one independently targeted reentry vehicle.

The missiles are currently deployed aboard the Navy’s 14 Ohio-class ballistic missile submarines.

Each operational Ohio-class submarine is limited to 20 Trident II D5 missiles. Four of its original 24 missile tubes have been permanently deactivated.

References: interestingengineering, TOI