Dockworkers rig an MK 48 torpedo for lifting ahead of a test Sept. 13, 2026. The U.S. and U.K. navies successfully test-fired the torpedo from Britain’s XV Excalibur, an uncrewed underwater vehicle, on Sept. 13, 2026. (U.S. Navy)
The United States and United Kingdom successfully launched an American torpedo from a British undersea drone this month, a “historic first” that could give the allies more ways to deploy weapons at sea.
The Sept. 13 trial, which took place at the British Underwater Test and Evaluation Center in Scotland, showed that a U.S. weapon could be fitted to and released from a British uncrewed vehicle.
Part of the Australian, U.K. and U.S. trilateral security partnership known as AUKUS, the project was implemented in less than seven months, the Navy said in a statement Tuesday.
“We are increasing the flexibility, scale and combat power of our combined forces and ensuring they are ready to meet the strategic demands of tomorrow,” Adm. Daryl Caudle, chief of naval operations, said in the statement.
The test also served as notice of NATO capabilities “in securing the north Atlantic, especially against those nations that wish to do us harm, like Russia,” Luke Pollard, U.K. minister for defense readiness and industry, told a British radio station.
European leaders believe the Kremlin is targeting undersea infrastructure, such as communication lines and pipelines. They blame Russia for a series of recent cable cuttings and other gray-zone attacks and provocations in Europe and the High North.
During the test, a 19-foot-long, 3,744-pound MK 48 torpedo was strapped to the underside of an XV Excalibur undersea drone and released, according to video released by the Navy.
The British navy’s XV Excalibur, an uncrewed underwater vehicle, is seen in this undated aerial photo. The U.S. and U.K. navies successfully test-fired an American MK 48 torpedo from the Excalibur, marking the first such launch from an unmanned platform for the two navies. (Courtesy of MSubs Ltd)
Civilian contractors and sailors assigned to the fast-attack submarine USS Santa Fe load an MK 48 torpedo at Naval Weapons Station Seal Beach, Calif., Sept. 8, 2026. The American and British navies successfully test-fired a U.S. MK 48 from the Excalibur, a U.K. military uncrewed underwater vehicle, on Sept. 13, 2026. (Tiarra Brown/U.S. Navy)
An American MK 48 torpedo is lowered into the water Sept. 13, 2026, for a test-firing that involved the U.S. and U.K. navies. They achieved the first-ever successful launch from an undersea drone for the two countries as part of the three-nation AUKUS partnership. (U.S. Navy)
It wasn’t clear whether the torpedo was programmed to hit a particular target or how the British undersea drone was controlled.
The Navy said the test confirmed that the torpedo and drone worked together mechanically and electronically, including their software, “proving that allied forces can rapidly achieve weapon interchangeability.”
The MK 48 is an acoustic-homing torpedo used by all classes of U.S. submarines. It carries a 650-pound warhead and has sophisticated sonar, digital guidance and control systems and digital fusing systems, according to the Navy.
Unveiled in May 2025, the 39-foot-long, XV Excalibur displaces nearly 21 tons and is Britain’s largest uncrewed undersea vehicle, according to the U.K. navy.
The joint initiative also directly supports an AUKUS mandate to quickly develop and field new asymmetric capabilities to bolster collective defense, the Navy statement said. AUKUS focuses on technology sharing in the Indo-Pacific to deter China.
The agreement includes regular rotations of U.S. and U.K. nuclear-powered submarines to Australia to be supported at an American naval base near the western Australian city of Perth.
It also calls for the sale of at least three used U.S. Virginia-class submarines to Australia, followed by the construction of a new class of nuclear-powered submarines for Australia and the U.K.
Following the successful deployment of the MK 48 from the XV Excalibur, the Navy and its international partners will work on integrating other equipment, improving how the vehicles are controlled and developing ways to use them in operations, the service said.
“We are not waiting 10 years for a single bespoke platform,” Vice Adm. Seiko Okano, director of the Navy’s Rapid Capabilities Office, said in the statement. “We are pioneering a modular, software-defined, open-systems approach that integrates allied hardware with commercial innovation to rapidly scale distributed lethality.”
