Lockheed Martin received a $540 million contract modification for Trident II ballistic fleet missile production and deployed system support.

The modification supports production efforts for the U.S. Navy and the British Royal Navy. The Trident II is currently equipped on the U.S. Navy's Ohio-class submarines as well as the Royal Navy's Vanguard-class submarines.

The U.S. Department of Defense says the work will be performed at various locations in California, Minnesota, Georgia, Washington, and several others, and expects the work to be complete by September 2021.

Lockheed Martin received roughly $453 million in weapon procurement funds from the Navy, plus an additional $50.7 million from the Royal Navy. The company also received $36 million in fiscal 2017 operation and maintenance funds, which are set to expire at the end of the current fiscal year.

The Strategic Systems Programs in Washington, D.C., is listed as the contracting activity.

The Trident II D5 missile is primarily produced by Lockheed Martin's Space Systems division, and has been used in over 160 flight tests since it was first designed in 1999.

Ballistic fleet missiles, also known as submarine-launched ballistic missiles, are designed to carry nuclear warheads. The United States began using this family of weapons with the Polaris A1 missile, which was powered by solid fuel rocket motors.