The future of war is unmanned and underwater

The Ukraine War offers a compelling moral reminder of a wronged people’s determination to resist naked aggression. From a more practical perspective, it has delivered a powerful technological message about the potential for unmanned systems in modern warfare. Deployed at scale, drones are fundamentally changing the character of combat.

On the other side of the world, the U.S. faces a direct military challenge from China, which seeks to overturn the U.S. alliance system in Asia through the conquest of Taiwan and domination of the Indo-Pacific. It is therefore time to learn and apply to this the lessons of Ukraine. For the same trend toward unmanned vehicles is likely to take hold in air-naval combat, given the similarities between ground-based and air-naval reconnaissance and attack. 

The U.S. must leverage its ability to develop autonomous systems to extend this transition to unmanned warfare underseas, investing in a fleet of unmanned underwater vehicles to complement traditional submarines and surface vessels.

The geographical problem is one of scale. The Chinese military grossly outmatches Taiwanese capabilities. But if the U.S. can apply its combat power directly in and around the Taiwan Strait, then all of its mass will simply become a target, just as so many massed forces have been swarmed by unmanned aerial systems on Ukrainian battlefields.

China’s objective will be to keep U.S. reconnaissance and strike assets as far away from the Taiwan Strait as possible — ideally, more than 1,000 kilometers out of combat range. Undersea capabilities will therefore prove decisive in this contest.

Currently, the balance of forces remains in our and our allies’ favor if forces are properly integrated. But the balance has narrowed considerably in even just the last five years. This makes a Chinese assault on Taiwan more likely in the event of marginal strategic changes.

The same trends that have affected ground and air-naval combat will shape the future of undersea warfare as well. Combat data from Ukraine demonstrates the enduring centrality of traditional artillery. However, a diverse unmanned systems fleet, alongside loitering munitions, has increased artillery accuracy and reduced engagement time, while making massed forces more vulnerable to attack.

This demands a re-imagining of military operations. Wars today and in the near future will be fought between militaries with well-integrated combined strike, reconnaissance, and command-and-control assets that enable rapid attacks. Both sides will attempt to fragment the enemy’s systems, allowing traditional assets to be massed.

China is thinking along these lines, seeking to reduce the range at which U.S. reconnaissance can identify Chinese assets. Its aim is to force the U.S. to risk high-value bombers and carriers to influence a Taiwan Strait engagement.

China has a robust air and missile defense system, surface strike capacity, and a growing anti-satellite program, but it still lacks a robust undersea warfare capacity, such as a seabed sensor system, an integrated anti-submarine surface fleet, or numerous anti-submarine aircraft.  Thus, undersea pressure will be vital to breaking apart China’s reconnaissance and strike abilities. Undersea assets can attack Chinese transports and warships. If armed with the right weapons, they can even hit high-value targets on the mainland.

American and allied strategy already has an undersea focus, most apparently through the AUKUS agreement. But a brittle industrial base restricts construction and repair capacity. The U.S. Navy should be able to field 40 of its 51 attack submarines at any given time, but it is in fact down to about 30 submarines due to maintenance overruns.

A sustained investment effort, combined with regulatory changes that allow major shipyards to contract a further in advance for complex subcomponents, is needed to restore resilience to the submarine industrial base. 

Yet the threat from China is near-term, not merely a future challenge. This necessitates an immediate combat capacity increase and the importance of a distributed, unmanned underwater vehicle fleet that can be fielded at scale alongside traditional submarines to enhance their usefulness — to increase submarine sensor range and free them up to engage higher-value targets.

Most fundamentally, this new undersea force requires its own doctrine, just as nascent aerial and submarine capabilities did in the interwar period, before their aggressive deployment in the 1940s. 

The major distinguishing characteristic of an undersea reconnaissance and attack system is technical. It remains extremely difficult for underwater vehicles, manned or unmanned, to communicate with each other reliably. Thus, the coordination of these unmanned assets faces technical difficulties, since networked methods require responsive communication between each element. Wireless networks and low-observable surface relays can help, but these require forward-deployment, and organic computational power demands a larger vehicle and power source.

The capacity to swarm these assets will increase both the distances over which they can be coordinated and the ability to execute offensive actions with them that are linked directly to a broader campaign plan. One practical approach might be a mothership-teaming model, in which a conventional submarine, or a smaller submarine built for deployment of unmanned vessels, launches and recovers a number of them quietly.

Shore delivery is also viable, since commercially-available medium-class unmanned underwater vehicles have a range of over about 400 kilometers and endurance of 100-plus hours. This would enable deployment from northern Luzon, the southern Ryukyu Islands, and Taiwan itself, if assets are prepositioned. A force of this sort could blunt an invasion, in addition to tracking and disabling Chinese anti-submarine mines, much like land-based aviation in the southwestern Pacific supported carriers during the Second World War.

Unmanned subs can also deploy aerial drones, enabling far more and far more affordable direct reconnaissance and strike support to U.S. warships and ground forces within Chinese missile range than traditional surface combatants could provide.  Equally relevant, modern torpedoes and mines can be deployed prior to conflict and activated remotely, enabling the creation of a robust defensive undersea network akin to a hardened fortification system on land.

Undersea and broader air-naval combat involves a large amount of spoofing and jamming for electronic deception, and unmanned vehicles will play a large part here. They can deployed with electronic warfare capacity or with systems that have their own jammers and electronic capacities. This can allow the U.S. to mask submarine movements and force an already limited Chinese anti-submarine warfare system to respond to fake submarine signatures, thereby forcing Chinese undersea assets to chase phantoms and waste valuable stockpiled weapons.

In the extended competition that we face with China, long-term investment will be crucial, given the reactions it can prompt that shape adversary investment and force design. The U.S. has the unsurpassed technological capacity to field a diverse fleet of unmanned underwater vehicles, alongside the research and innovation system to solve the technical problems that the current technology presents. We ought to get on with it.

Seth Cropsey is the founder and president of Yorktown Institute. He served as a naval officer and as deputy Undersecretary of the Navy and is the author of Mayday and Seablindness.