HMS Vigilant, one of the Royal Navy's Trident nuclear weapon submarines, has conducted the first UK test firing of an unarmed Trident D5 ballistic missile for three years in the Atlantic Ocean following post-refit sea trials.
The launch took place on October 23 2012 with United States Navy support at the US Eastern Test Range off the coast of Florida. The unarmed missile was converted into a test configuration using a kit produced by its manufacturers, Lockheed Martin, that contains the tracking systems, flight telemetry instrumentation, and safety devices required for the test.
HMS Vigilant left Devonport Naval Base in June 2012 following completion of a mid-life Long Overhaul Period refit which began in autumn 2008. The missile test launch is the final stage in trials before the submarine returns to operational patrols. Before recommencing routine patrols the submarine crew completes a series of routine exercises known as Demonstration and Shakedown Operations (DASO) during which they are assessed on their competence in handling the submarine and readiness for operational deployment.
The test firing also provides data on the reliability and accuracy data of the missile and, in the eyes of politicians, demonstrates the effectiveness of the Trident nuclear weapons system to other states.
The UK has purchased rights to 58 Trident D5 missiles, at a cost of around £17 million per missile, from a common pool of US and UK missiles which is maintained by Lockheed Martin at the US Naval Submarine Base Kings Bay, Georgia. After refit, UK Trident submarines sail to Kings Bay where the missiles are installed on the submarine without warheads. The warheads are loaded onto missiles at the Coulport Trident base after the submarine has returned to Scotland from the USA.
Lockheed Martin provides support to the Royal Navy's Trident programme under the terms of the 1963 US – UK Polaris Sales Agreement, which was modified in 1982 to enable the UK to acquire the Trident II D5 ballistic missile system from the USA. Lockheed Martin provides programme management and engineering services for the UK Trident missile system through an annual contract funded by the Royal Navy, with work performed in the facilities at both Kings Bay in the USA and Coulport in the UK. This is the tenth occasion that the UK has conducted a Trident D5 missile test firing. The US Navy has undertaken 133 Trident D5 test flights.