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The U.S. Navy’s Plans for Unmanned and Autonomous Systems Leave Too Much Unexplained

The U.S. Navy is moving forward with its plans for a more distributed fleet in which intelligent unmanned or autonomous platforms will play a significant role. Unfortunately, many of the details about these novel systems are left to the imagination — often a poor substitute for filling in the blanks. It may be that the blanks cannot be satisfactorily filled when describing the infrastructure for sustaining these unmanned systems. Rightly or wrongly, the Navy focuses most of its discussion on the direct offensive contributions of unmanned systems for combat with major powers on warfighting impact and metrics such as effects on targets, capacity, and tempo. Less discussion focuses on the indirect sustainment tasks.

This is not to dispute that the Navy recognizes important combat-supporting missions for unmanned or autonomous systems, such as airborne refueling of manned aircraft with the MQ-25 Stingray, surveillance and reconnaissance from the MQ-4C Triton, and automated support for interpreting many hours of surveillance video by Project Maven. But the Navy has not publicly said how it will sustain a fleet of unmanned systems through multiple launches and recoveries, how or where they will be refueled and repaired, or described a concept of operation for how it plans to use them.

Not all automated systems will be offboard platforms, of course. Automation will have a role to play in some of a ship’s onboard defensive systems. Our concern, however, is with offboard air, surface, and subsurface unmanned vehicles that will operate with some degree of autonomy. It matters logistically whether these offboard systems are expendable or recoverable because recoverable systems must not only be launched, but also retrieved, refueled (or recharged), and maintained during the potentially long pre-combat period. Launching and recovering those systems will occur with some regularity measured in hours, days, or weeks. How often depends on design details of the systems themselves, but smaller systems require quicker turnarounds (e.g., hours or days), and thus daily launch and recovery operations should be expected, along with the significant logistical burdens that must be borne for this to happen.

Furthermore, most of the Navy’s discussions are couched in terms of operations after bullets have started flying, omitting details about what happens during the days, weeks, and months before combat begins. Because of that, there is little discussion of the infrastructure to support those pre-combat operations — infrastructure that would seem to include “motherships” and overseas land support bases for the unmanned systems if the Navy is employing tens to hundreds of these systems. Explanations from the Navy as to how this will happen are sparse, and one might be excused for thinking there is no significant cost or preparation required at all.

This leads to a fundamental tradeoff without a good solution. If the Navy wants to develop small quantities of intelligent, precision offensive unmanned systems, then those systems should be regarded as valuable and require their own (costly) defensive measures. Otherwise they become effectively expendable. Conversely, if the Navy wants to emphasize quantity over quality with inexpensive mass (such as “swarms”), it needs to recognize that there is great advantage to the side that owns the nearby land where even larger quantities of such unmanned systems can be generated. In swarm warfare, quantity trumps quality. Either way, there is an infrastructure tail that cannot be ignored.

Stepping Back: What Problem Is the Navy Trying to Solve?

To its credit, the Navy acknowledges the thorny problems with the command and control of unmanned systems, recognizing degrees of autonomy in a spectrum ranging from human-operated systems at one end to near-independent autonomous systems at the other end. Midway between those extremes are human-supervised systems and human-machine teaming. We are not going to dissect this spectrum any further and will simply refer generically to unmanned systems, recognizing that missions and technology will imply different degrees of autonomy.

There are a multitude of ways to describe the problems that unmanned systems might solve, but all should be about shifting the cost balance in favor of the United States. In that context, one might seek to fill in the following blank: Unmanned or autonomous systems solve challenges that are too _____________ for traditional warfighting approaches.

Possibilities for filling in this blank include “tedious or boring”: long-duration surveillance and reconnaissance are good examples of this; “overwhelming,” as in large salvos of anti-ship missiles, or enemy swarms; “dangerous”: missions inside the ever-expanding enemy airspace and sea space are challenges that might be addressed with unmanned systems; or “physiologically taxing,” because humans need oxygen, in scarce supply at high altitudes and not readily available beneath the surface. Nor is human physiology consistent with long-duration missions in tightly confined spaces. Other problems unmanned or autonomous systems could solve might be situations moving too fast for traditional approaches — electronic warfare and electronic spectrum management fit into this category, as do hypersonic weapons although many of these might be addressed through onboard rather than offboard systems — or where a traditional, manned approach might be too expensive, though the Department of Defense’s record in this area is not stellar.

Technology Matters

Technology to support unmanned systems has been evolving for decades, even centuries. These technologies, including those involving air, surface, and subsurface systems, continue to advance for naval applications.

Along the way, some of the technology endeavors have been unsuccessful even at small scale, but progress has been most pronounced for surveillance, mostly airborne, transitioning from legacy strategic spaceborne surveillance to newer operational and tactical airborne surveillance. When the dust settles, it may be that surveillance from space, air, surface, and subsurface proves to be the most fruitful application of unmanned technologies.

Technology advancements are not limited to the unmanned offboard systems themselves, but also to approaches for launching and recovering them at sea in both calm and rough waters. For these tasks, however, operating at a large scale is a daunting challenge. Missing from the technology discussions is how the Navy plans to sustain large quantities of unmanned systems for pre-combat and combat phases of operations. The laws of physics are not the limiting feature for launching and recovering large numbers of offboard systems — the supporting infrastructure is. Nearly 25 years ago, the Navy demonstrated its ability to generate an impressive 771 (manned) aircraft strike sorties over a period of four days from the aircraft carrier Nimitz. That is a clear example of launching, recovering, refueling, and maintaining offboard systems at scale. But it is not an inexpensive example.

Sustainment at Sea: The Silence Is Deafening

The Navy can sustain small numbers of unmanned systems today. If that is the future that the Navy envisions, with only small quantities of systems that may be superb in quality and capability, it should say so. But the illusion created by the Navy’s strategy, whether intentional or not, is that the number of offboard unmanned systems in use will not be small. Furthermore, unless the offboard systems have exceedingly long range and endurance, launching and recovering them must be done with some proximity to their operational locations, presumably at risk of attack from the adversary.

This begs the question: What part of the Navy force structure and budget will be used for large-scale sustainment of unmanned systems at sea? There are some possibilities, but none look particularly attractive.

For example, one possibility is expeditionary sea bases. There are currently five of these ships either built or planned that, depending on system design, could be adapted or retrofitted for launch and recovery operations of multiple systems, although how many and how quickly is unclear. Probably only two or three of these sea bases would be available in an overseas theater during the weeks and months before combat, and they could become high-value targets for the adversary.

Another possibility is expeditionary fast transports. These vessels were designed for speed, and although they can deploy or retrieve an unmanned vessel with their onboard cranes, that process would be too slow to support large quantities of routine launches and recoveries. Littoral combat ships are another consideration and like the expeditionary fast transports, these ships can perform launch and recovery operations but would do so slowly (i.e., one at a time).

The Navy might use amphibious ships with well decks and flight decks. These warships are an option, but they are not optimal for launch and recovery operations, nor would retasking them to this effect be optimal for the marines who conduct missions with these ships.

Submarines have some role to play. These boats have capability, but limited capacity, for launching and recovering (mostly undersea) systems. Routine maintenance of those systems aboard the submarine is unlikely.

Nearby land bases are another possibility, but not a certainty. As the U.S. Marine Corps’ expeditionary advanced base operations concept evolves, the Navy might find that unmanned systems can be useful for the defense of these land bases, but their role for offense is less certain.

Finally, a new class of support ship is always an option, but there is no public discussion of this option and nothing in the Navy’s current shipbuilding plan. The silence is, indeed, deafening.

What About ‘Swarms’ of Unmanned Systems?

Iran has long posed the technical possibility of a swarm by sea, and the Navy sometimes speaks of having its own swarm capabilities, although that discussion appears to be transitioning from sea swarms to air swarms. Nonetheless, the Navy’s current strategy for intelligent autonomous systems leaves its intentions for swarm warfare ambiguous.

For a swarm to be affordable, it almost by definition must be made of platforms that are relatively small individually. Thus, a fundamental property of swarms is that the side with nearby land support (for launching, recovering, refueling, and maintaining) has a lopsided advantage. It is difficult to see how the Navy could prevail with a swarm strategy against China, Russia, or even Iran. This limitation can be seen through classical Lanchester modeling, which, although inappropriate for precision fires and warfare, is insightful for mass warfare of a swarm variety. Through that modeling, it is easy to see that quantity trumps quality. For example, if the adversary has twice the number of swarm vehicles that the Navy does, the Navy would need four times (two-squared) the combat effectiveness to (mathematically) reach a stalemate. A good dose of hubris might allow that assumption to be made, but if the adversary has 10 times the numbers, the Navy would need 100 times (10-squared) the combat effectiveness. It is hard to see China or Russia not achieving that level of quantitative superiority. Iran already has an increasing number of small maritime fast and inshore attack craft that can be used for swarming much larger vessels.

Consider the case study of the Nagorno-Karabakh war cited in the Navy’s strategy.

In the fall of 2020, Azerbaijan decisively defeated Armenia in a 44-day conflict. Despite both sides’ modern air defenses precluding traditional (manned) air combat, Azerbaijani employed superior unmanned air systems (UAS) in multiple ways. Kinetically, they used UAS as targeting assets for loitering munitions and weaponized UAS to directly strike tanks, radars, etc. In the Information Warfare domain, UAS live-streamed footage of Armenian losses, enabled viral videos on social media, and supported a devastating propaganda campaign. While UAS were not the sole contributor to the overall decisive victory, this yet again illustrates the highly disruptive potential of unmanned systems – and signals what the future potentially holds as these systems become [Intelligent Autonomous Systems].

Could we imagine this Azerbaijani prowess if it were fighting thousands of miles from its own territory as the Navy would be? Azerbaijan had the geographic proximity needed to support its unmanned air systems, and that proximity was critically important for the execution of those operations. Because the Navy envisions fighting in distant waters, such as the South China Sea, swarms would make better offense for the “home team” than for the “visiting team,” making swarm defense more important for the Navy than swarm offense for the simple reason that it is unlikely to have sufficient swarm quantities to dominate offensively.

Toward a Meaningful Concept of Operations

Unmanned or autonomous platforms have some roles to play (especially in surveillance and reconnaissance), but the quantities that are required for naval operations must be married with a sustainment plan — and maybe a shipbuilding plan — to support that level of operations both during combat and in the days, weeks, and months before combat operations ratchet up. A meaningful concept of operations must address this.

There could be a significant sticker shock, perhaps leading to lowered expectations for the overall contributions of unmanned systems. It is okay if the Navy keeps me in the dark regarding its plans, but it is not okay to keep itself in the dark.

Dr. Gregory V. Cox is a semi-retired national security professional with nearly 50 years of experience, mostly with Navy systems and operations. Over his career he has observed multiple launch and recovery operations from Navy ships with (manned and unmanned) offboard air, surface, and subsurface systems. Previously on the research staffs at the Center for Naval Analyses and the Institute for Defense Analyses, he currently holds adjunct positions with the Institute for Defense Analyses and Johns Hopkins University. The views expressed here are nonetheless his own.

Photo by Mass Communication Specialist 3rd Class Sang Kim

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