U.S. and U.K. navies reportedly launch a 3,700-pound torpedo from a drone submarine

The Mk 48 is designed for attacks on deep-diving submarines and high-performance surface ships. It is normally launched from crewed submarines. The trial validated the mechanical, electrical and software connections needed to carry and fire it from the British drone.

Project Broadsword received approval from the Department of the Navy Rapid Capabilities Office in February 2026 and reached the trial in seven months. The work included the U.S. Navy, Royal Navy, Defense Innovation Unit, Naval Undersea Warfare Center Keyport and industry partners.

The next phase shifts to integration

The Navy says the follow-on effort, Project CUTLASS, will use Anduril's Dive-XL platform to test more advanced payload integration, command-and-control systems and tactical scenarios.

A successful launch proves compatibility in a controlled trial, not a fully fielded autonomous weapons program. The next work will determine how the system is commanded, how payload data moves between allied platforms and how an uncrewed submarine would be used operationally.