U.S. Navy Upgrades Virginia and Columbia Submarines With New 360° Infrared Imaging Masts.

The U.S. Navy is investing $139 million in new Low-Profile Masts to help Virginia-class attack submarines and Columbia-class ballistic missile submarines monitor contested seas while reducing the risk of revealing their position. L3Harris announced the NAVSEA award on September 21, 2026, as U.S. submarines face increasingly dense Chinese and Russian undersea, surface, and airborne surveillance networks.

The Type 20 and Type 24 masts combine high-definition visible and infrared imaging with 360-degree sensing, giving crews a faster picture of activity above the water while limiting sensor exposure. The upgrade strengthens submarine survivability and situational awareness in regions such as the Indo-Pacific, North Atlantic and Arctic, where stealth remains central to strike, intelligence and strategic deterrence missions.

Related Topic: U.S. Navy Reclassifies 19 Planned Virginia-Class Submarines to Form Next-Generation Strike Fleet

The U.S. Navy has awarded L3Harris a $139 million contract to deliver additional Type 20 and Type 24 Low-Profile Masts for Virginia-class attack submarines and Columbia-class ballistic missile submarines, enhancing visible, infrared and 360-degree sensing while supporting submarine stealth. (Picture source: L3HARRIS)

This capability is becoming more important as China and Russia invest in submarines, surface combatants, maritime patrol aircraft, unmanned sensors, and broader surveillance architectures designed to detect hostile forces across increasingly contested seas. For a Virginia-class submarine operating near Chinese naval forces in the Indo-Pacific, or monitoring Russian submarine activity in the North Atlantic and Arctic, the tactical problem is increasingly simple but demanding: obtain enough information to identify threats and make decisions without staying exposed long enough for an adversary to detect the submarine.

Unlike a traditional hull-penetrating periscope, a digital photonics mast places visible and infrared cameras on telescoping arms and sends the imagery electronically to displays inside the submarine. The U.S. Navy confirms that Virginia-class submarines already use two photonics masts fitted with visible and infrared digital cameras rather than conventional optical periscopes, a design that also lets the control room move away from the pressure hull’s curvature and improves the layout available to the command team.

The Type 20 and Type 24 Low-Profile Masts extend the military value of that architecture by combining high-definition imaging with panoramic awareness. Instead of relying on a narrow visual observation through a traditional periscope, submarine crews can digitally assess contacts around the boat and distribute imagery to operators who can compare it with sonar, navigation, and electronic-support data. The result is not simply a clearer picture, but potentially a shorter decision cycle between raising a mast, identifying what is happening above the submarine, and returning to deeper water.

That timing matters because operating near periscope depth can create vulnerabilities that do not exist while a submarine remains deep and acoustically concealed. A raised mast can potentially be detected visually or by electro-optical surveillance, while wake and other surface effects can also betray submarine activity. In a future conflict against China or Russia, where surveillance may be distributed across ships, aircraft, satellites, unmanned systems and shore-based sensors, every unnecessary second of mast exposure can increase the opportunity for an opponent to establish a submarine’s approximate position.

For the Virginia-class submarine, this directly affects combat operations. The class is designed for anti-submarine warfare, anti-surface warfare, intelligence collection, land attack, and special operations missions, and the Navy describes Virginia-class boats as incorporating major improvements for littoral operations. Their photonics masts form part of a broader digital combat architecture intended to maintain situational awareness while allowing rapid introduction of new sensors and payloads throughout the class’s service life.

In a potential Indo-Pacific submarine war, the mast’s value becomes easier to understand. A Virginia-class submarine attempting to penetrate or operate inside waters monitored by Chinese forces would rely primarily on passive sonar and other low-signature sensors to avoid disclosing its position. But acoustic information does not always provide the visual identification needed to confirm whether a surface contact is a warship, merchant vessel, or other object, nor does it replace visual awareness when navigating congested or coastal waters. A digital mast gives the commander another way to resolve that uncertainty without requiring prolonged exposure at the surface.

This is especially relevant as the People's Liberation Army Navy (Chinese Navy) continues to expand its submarine and anti-submarine warfare capabilities. Chinese naval forces increasingly operate as part of a wider reconnaissance structure that can include surface combatants, maritime patrol aircraft, fixed and mobile sensors, satellites, and unmanned systems. The challenge for an American attack submarine is therefore no longer simply avoiding another submarine’s sonar; it is avoiding a broader detection chain in which one sensor can potentially cue another asset to investigate the contact.

A Low-Profile Mast does not make a Virginia-class submarine invisible, and it does not replace sonar or electronic surveillance. Its operational value lies in helping commanders use visual and infrared information selectively, acquire the information they need, and then return the boat to the deeper, lower-signature operating environment where nuclear attack submarines retain their greatest advantage. In this sense, improved mast sensors contribute directly to the broader competition between detection and concealment that defines modern undersea warfare.

The same logic applies against Russia, although the geography and threat environment differ. Russian nuclear-powered attack submarines remain a major concern in the North Atlantic, Norwegian Sea and Arctic, where U.S. and allied forces must monitor approaches connecting Russia’s Northern Fleet operating areas with the wider Atlantic. Modern Russian submarines, including the Yasen family, combine advanced quieting with long-range cruise missile capability, increasing the importance of maintaining continuous undersea awareness around NATO’s northern approaches.

For Virginia-class crews operating in these regions, Low-Profile Masts can provide valuable visual and infrared information during near-surface operations, particularly in demanding High North conditions where darkness, weather, ice, and constrained navigation can complicate submarine operations. The requirement remains the same: collect enough information to navigate and understand the tactical environment while minimizing opportunities for Russian forces to detect the submarine.

The Columbia-class submarine creates a different but strategically more sensitive requirement. The Navy identifies Columbia as the future sea-based strategic deterrent and says the class will provide the most survivable leg of the U.S. nuclear triad, replacing the Ohio-class SSBN force and sustaining strategic deterrence into the 2080s. Its fundamental mission depends not on finding adversary submarines for tactical attack, but on remaining extremely difficult to locate throughout deterrent patrols.

For a Columbia-class ballistic missile submarine, a digital mast therefore supports survivability rather than offensive targeting. The SSBN still requires reliable information about surface contacts, navigational conditions, and potential hazards when operating near shallow depth or conducting evolutions that require visual awareness. High-resolution visible and infrared imaging, combined with 360-degree sensing, can give the crew that information while minimizing how long the submarine has to expose equipment above the water.

The threat environment makes this increasingly significant. Both China and Russia are improving the forces and sensors available for anti-submarine warfare, while the United States depends on its SSBN force remaining sufficiently concealed to guarantee a retaliatory nuclear capability even after a major attack. Any sensor improvement that helps a Columbia-class submarine collect necessary information while reducing opportunities for adversary detection therefore supports the broader survivability of the sea-based nuclear deterrent.

This is where the Virginia- and Columbia-class missions diverge. For the Virginia-class submarine, Type 20 and Type 24 masts can support tactical decision-making in waters where the crew may be hunting submarines, monitoring surface forces, or collecting intelligence against China or Russia. For the Columbia-class submarine, the same shift toward advanced digital sensing supports a fundamentally defensive objective: maintaining awareness without compromising the concealment that gives an SSBN its strategic value.

The $139 million L3Harris contract therefore addresses a larger problem than submarine optics. As China and Russia expand the number and variety of sensors that could help locate U.S. submarines, the U.S. Navy is investing in technology intended to improve what its crews can see while reducing how much they must reveal themselves to see it. For Virginia-class attack submarines preparing for high-end undersea warfare in the Indo-Pacific or North Atlantic, and for Columbia-class ballistic missile submarines expected to remain hidden during strategic patrols, that balance between sensing and stealth is becoming a defining requirement of future submarine warfare.

Explore More Defense News

• Land Defense News
• Naval Defense News
• Defense Aerospace News

Written by Alain Servaes – Chief Editor, Army Recognition Group
Alain Servaes is a former infantry non-commissioned officer and the founder of Army Recognition. With over 20 years in defense journalism, he provides expert analysis on military equipment, NATO operations, and the global defense industry.