The U.S. Navy supported the Oct. 23 launch of a U.K. Royal Navy Trident II D5 Fleet Ballistic Missile (FBM) built by Lockheed Martin (NYSE: LMT). The unarmed missile was launched from the submerged Royal Navy submarine HMS Vigilant in the Atlantic Ocean.

The test marked the 143^rd successful test flight of the Trident II D5 missile since design completion in 1989 – a reliability record unmatched by any other large ballistic missile or space launch vehicle.

“The Royal Navy and the U.S. Navy continue to demonstrate the readiness and reliability of this highly capable system, whose mission is to discourage aggression,” said Melanie A. Sloane, vice president of Fleet Ballistic Missile programs, Lockheed Martin Space Systems Company, the Trident missile prime contractor. “The cooperation of both governments, supported by industry, provides a credible submarine-based strategic deterrent.”

The test, which was part of a Demonstration and Shakedown Operation that verified the integrity of the strategic weapon system following an overhaul of the submarine, was the 10^th consecutive successful Trident II D5 missile test flight by the U.K. since 1994. The missile was converted into a test configuration using a test missile kit produced by Lockheed Martin that contains range safety devices, tracking systems and flight telemetry instrumentation.

First deployed in 1990, the D5 missile is currently aboard U.S. Navy OHIO-class and Royal Navy VANGUARD-class submarines. The three-stage, solid-propellant, inertial-guided ballistic missile can travel a nominal range of 4,000 nautical miles and carries multiple independently targeted reentry vehicles.

Lockheed Martin Space Systems has been the U.S. Navy’s prime strategic missile contractor since the inception of the Fleet Ballistic Missile program more than 50 years ago. Since 1968, Lockheed Martin has provided program support to the Royal Navy under the terms of the 1963 U.S.-U.K. Polaris Sales Agreement, which was modified in 1982 to provide for the Trident II D5 ballistic missile system. Lockheed Martin provides program management and engineering services for the United Kingdom’s Trident missile system through an annual contract funded by the U.K. Royal Navy, with work performed at facilities in the U.S. and the U.K.

Lockheed Martin press release