The Navy on Thursday awarded the submarine building division of General Dynamics [GD] a $5.1 billion contract to complete design work on the Columbia-class ballistic missile submarines.

The detailed design award, which includes $175.1 million in initial funding, is for the Integrated Product and Process Development and additional work, including “component and technology development, missile tube module and reactor compartment bulkhead prototyping and manufacturing efforts, and United Kingdom Strategic Weapons Support System kit manufacturing,” the Navy said last evening.

“Working closely with the Navy and the submarine industrial base, Electric Boat will continue to lead critical aspects of the Columbia-class development effort, including design, material procurement, construction and operating-cost reduction, to achieve an affordable and effective program,” Jeffrey Geiger, president of GD’s Electric Boat division, said in a statement.

The design contract also funds ongoing development of the Common Missile Compartment, which will be integrated into the Columbia-class vessels and the Royal Navy’s Dreadnought-class ballistic missile sub, GD said.

Huntington Ingalls Industries [HII] is a partner to GD on the work at its Newport News Shipbuilding division. HII will do nearly 13 percent of the design work, the Navy said.

“The award of the detail design contact to Electric Boat kicks off the next critical phase of the Columbia class program,” Rep. Joe Courtney (D-Conn.), whose district includes Electric Boat, said in a statement.

GD said construction of the lead vessel will begin in the fall of 2020. The Navy plans to by 12 of the submarines. The design work is expected to be 83 percent complete by then, Courtney said.