10,000-ton US nuclear submarine to get new turbine generators for powering systems

Northrop Grumman has finalized an order to supply propulsion machinery and onboard power generators for 12 additional Virginia-class Block VI submarine shipsets, extending its work on the Navy program through 2032.

The $1.4 billion contract covers main propulsion units and ship service turbine generators, Chief Executive Kathy Warden told analysts during the company’s October 20 earnings call.

In a separate contract, the Navy contracted Northrop to produce AN/WSN-12 inertial navigation systems, which use fiber-optic gyroscopes to help ships and submarines determine their position and motion when GPS is unavailable or unreliable.

The initial contract is worth $29.2 million, with options that could raise its value to $103.6 million.

Propulsion and onboard power

The Virginia-class procurement covers two equipment categories with distinct roles: main propulsion units for driving the submarines and ship service turbine generators for supplying onboard electrical power.

“We also definitized the Virginia-class Block VI submarine procurement for an additional 12 shipsets of main propulsion units and ship service turbine generators,” Warden said.

“The award value adds $1.4 billion to backlog, supporting our partnership with the Navy through 2032,” he said.

The announcement concerns equipment procurement for the submarine program. It does not establish delivery dates for individual vessels or describe changes to propulsion performance.

Chief Financial Officer John Greene said higher marine systems volumes helped lift third-quarter sales at Northrop’s Mission Systems division by 2%. Increased activity on restricted airborne radar programs also contributed.

Navigation without continuous GPS

The separate AN/WSN-12 award addresses a different operational requirement: maintaining navigation information without continuously relying on external positioning signals.

Inertial navigation systems use gyroscopes and accelerometers to measure motion and calculate navigation information from an initial position. The AN/WSN-12 packages this capability into an Inertial Sensor Module and a Navigation Processor Module.

Its central technology change is the use of fiber-optic gyroscopes instead of the ring-laser gyroscopes found in the legacy AN/WSN-7.

The Navy describes the replacement as compatible in form, fit, and function with the older system, allowing installation on existing vessels as well as new construction.

Its navigation output can also feed other shipboard systems that require accurate position, velocity, and attitude data. Acquisition plans call for deployment across surface ships, submarines, and aircraft carriers.

Production and fleet upgrades

The navigation contract could reach $103.6 million if all options are exercised. It combines purchases for the Navy, accounting for 27%, with Canada at 42% and Australia at 31% through the Foreign Military Sales program.

Work will take place primarily in Charlottesville, Virginia, with the remainder in Baltimore. Completion is expected by May 2030, extending through July 2032 if all options are exercised.

A separate planned full-rate production effort covers additional hardware, engineering support, training, testing, and spares. That effort would support new-construction vessels, fleet retrofits, and foreign military deliveries from fiscal 2031 through fiscal 2036.

Together, the awards span submarine machinery and fleet navigation. Their schedules and procurement scopes remain separate, covering propulsion equipment on one side and navigation production, integration, testing, and support on the other.