Key Points and Summary – China’s A2/AD strategy has a “quiet” new component: a “consequential” fleet of unmanned underwater vehicles (UUVs) designed to swarm and “lock out” U.S. carriers.
-While the U.S. remains “wedded” to a few “highly valuable” carriers, China is rapidly producing cheap, autonomous systems (like the HSU-001) for ISR, mining, and attack.
USS John C. Stennis Carrier. Image Credit: Creative Commons.
-This “invisible weak spot” is exacerbated by the U.S. Navy being “behind the curve,” with its own (Orca, Snakehead) UUV programs “years behind schedule” and “over budget.”
The Navy’s Invisible Weak Spot: China’s Unmanned Systems in the Indo-Pacific
For the past twenty years, Beijing has quietly built up an anti-access/area denial (A2/AD) force to challenge the United States’ single most potent tool of sea control: the aircraft carrier.
China invested two complementary efforts in this strategy. One is the well-publicized development of long-range “carrier-killer” missiles, such as the DF-21D and DF-26, supported by a growing web of space-based and over-the-horizon sensors.
The other has been quieter but may ultimately prove more consequential: the build-up of an unmanned underwater vehicle (UUV) force for reconnaissance, mine-laying, and, eventually, attack. A small fleet today, these unmanned underwater systems are poised to grow.
As it does, it could help lock the US Navy out of the Indo-Pacific.
The Carrier Comes into Focus
The aircraft carrier is the iconic platform of American sea power, the ultimate symbol of mobility, flexibility, and lethality. Since 1945, carriers have enabled the US to project force from Korea to the Persian Gulf and to reassure allies and deter aggression without reliance on foreign bases.
A single carrier strike group can project air superiority, conduct precision strikes, and control vast ocean areas from East Africa to the South China Sea. Its presence is a show of capability; its absence is an operational deficit.
U.S. Navy Lt. Andrew Bentley signals an F/A-18E Super Hornet, assigned to the “Blue Blasters” of Strike Fighter Squadron (VFA) 34, to launch from the flight deck of the Nimitz-class aircraft carrier USS Theodore Roosevelt (CVN 71), Nov. 30, 2023. Theodore Roosevelt, the flagship of Carrier Strike Group Nine (CSG 9), is conducting integrated training exercises in the U.S. 3rd Fleet area of operations. (U.S. Navy photo by Mass Communication Specialist 3rd Class Adina Phebus)
China’s leaders understand this better than most. In the South China Sea and elsewhere, they recognize that the US Navy’s ability to move and operate freely in the Indo-Pacific means Beijing will never be able to fully control its near seas.
China’s response has been to make it as costly as possible for the US Navy to operate, employing an asymmetric blend of long-range missiles, high-tech surveillance systems, and, increasingly, undersea systems.
China’s A2/AD Network
China’s A2/AD campaign began with the DF-21D anti-ship ballistic missile, which entered service in the mid-2000s and quickly became known as the “carrier killer.” A newer missile, the DF-26, can reportedly hit targets as far as 3,400 kilometers away, putting US forces on Guam in range.
The effectiveness of these systems, when combined with hypersonic weapons, precision cruise missiles, and advanced targeting, is already transforming the threat environment for carriers. By making their operations more uncertain, this missile network has effectively shrunk the ocean space in which they can operate unencumbered.
Its purpose is not necessarily to sink carriers outright, but to make their deployment and employment risky and therefore politically costly. The result is a dense, layered maritime exclusion zone that stretches from the Western Pacific into the Indian Ocean and beyond—a zone that will effectively constrain US movement and cloud every operational decision.
China’s Push Under the Waves
While the DF-21D and its derivatives have rightly received much attention, China’s investments in unmanned underwater systems may ultimately pose a more significant threat to the carrier. In recent years, the PLA Navy (PLAN) has quietly developed and fielded a number of UUVs for intelligence gathering, surveillance, reconnaissance (ISR), mine warfare, and anti-submarine warfare. These include small, man-portable models as well as medium- and large-displacement systems, such as the deep-water optimized, 12-meter-long HSU-001.
Future UUVs are expected to incorporate greater artificial intelligence, autonomous sensor networking, and swarm coordination to form cohesive teams that can operate as a new form of “distributed lethality.”
Fleets of autonomous UUVs in coordinated swarms would be able to share ISR data, track individual targets, and take collective action. In theory, they could follow and shadow US carrier strike groups, pass targeting data to the missile system, and, eventually, carry out actual attacks.
While many of these systems remain in the prototype or development phase, the trajectory of Chinese investment is clear. The PLAN is seeking to match the carrier in the undersea domain with systems that can penetrate beneath its defenses and deny it sanctuary—thereby remaking the undersea battlespace as a contested space where the U.S. Navy can no longer be assured of any decisive advantage.
The US Navy Behind the Curve
The United States Navy is not oblivious to this challenge, but it has been slow to respond to it. It is now developing its own large and extra-large UUVs (LUUVs and XLUUVs) to extend undersea awareness and facilitate sea control in littoral zones.
The Navy’s Orca program, and to a lesser extent the Snakehead program, have been developed to deploy fleets of unmanned underwater vehicles for ISR, mine warfare, and anti-submarine warfare in areas like the South China Sea. However, both programs are years behind schedule and are over budget. As importantly, the U.S. Navy has been slow to integrate unmanned platforms into its larger operating concepts.
In this regard, the US military-industrial complex has a decided disadvantage compared to the PLAN. The Chinese defense industry has, for strategic and institutional reasons, been able to leverage advances in AI, energy sources, underwater communications, and other key areas from its own civilian sector far more rapidly than the US military can. In so doing, the PLAN has a decided speed and flexibility that the US, with its famously cumbersome procurement system, has struggled to match.
The difference is one of philosophy. China is dispersing capability across multiple networks of cheap, expendable, and autonomous platforms while the United States remains wedded to a small number of highly valuable and concentrated assets. One side prizes the concentration of power, while the other prizes its disruption.
Resilience in a World of Distributed Lethality
For the United States to retain any credible form of sea power in the Indo-Pacific in this environment, it must adapt. This will not be easy and will require the Navy to change some of its core assumptions. The carrier strike group will remain the center of U.S. operations in the region.
Still, its role will need to change from being the solitary crown jewel of American power projection to one node in a larger network of manned and unmanned systems. Its command and control functions will need to be combined with a distributed architecture of sensors and autonomous assets that can detect and counter undersea threats before they reach their targets.
This also requires a far deeper level of integration and cooperation with allies and partners. From information sharing to data fusion to interoperability between navies, all will be necessary to counter China’s own increasingly networked approach to warfighting.
As a result, the future of naval warfare will likely come to rest less on the massing of platforms than on the networking of intelligence, information, and decision-making.
The Strategic Test
In the coming decades, China’s A2/AD system—a system of missiles, sensors, and autonomous systems—will present the most serious challenge to American sea power since the carrier was born. It is not a network built to beat the U.S. Navy in a fair fight.
Instead, its purpose is to deny, delay, slow decision-making, and erode the freedom of movement of the U.S. Navy without ever having to fire the first shot.
The U.S. Navy may have the most capable surface fleet in the world, but that does not mean it can command the seas. Nor, in a system where the weakest point is the least visible one, does it mean that its assets are any longer invulnerable.
The ultimate contest for maritime control in the Indo-Pacific will now be played out in the water below, where detection is transient, communications are limited, and machines are just beginning to think for themselves.
The aircraft carrier will remain the central symbol of American sea power. Still, by itself it can no longer hope to function as the lynchpin of any strategy in a contested Indo-Pacific. If the Navy is to endure and prevail in that future environment, it will have to adapt to a world in which resilience supersedes concentration and situational awareness rivals firepower. If it does not, the jewel of American sea power may become its weakest link in a battlespace few can see—and fewer yet understand.
About the Author: Dr. Andrew Latham
Andrew Latham is a non-resident fellow at Defense Priorities and a professor of international relations and political theory at Macalester College in Saint Paul, MN. You can follow him on X: @aakatham. He writes a daily column for the National Security Journal.
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