Tag Archives: unmanned

Unmanned Systems: A New Era for the U.S. Navy?

July 18, 2016 Guest Author 1 Comment

By Marjorie Greene

The U.S. Navy’s Unmanned Systems Directorate, or N99, was formally stood up this past September with the focused mission of quickly assessing emerging technologies and applying them to unmanned platforms. The Director of Unmanned Warfare Systems is Rear Adm. Robert Girrier, who was recently interviewed by Scout Warrior, and outlined a new, evolving Navy Drone Strategy.

The idea is to capitalize upon the accelerating speed of computer processing and rapid improvements in the development of autonomy-increasing algorithms; this will allow unmanned systems to quickly operate with an improved level of autonomy, function together as part of an integrated network, and more quickly perform a wider range of functions without needing every individual task controlled by humans. “We aim to harness these technologies. In the next five years or so we are going to try to move from human operated systems to ones that are less dependent on people. Technology is going to enable increased autonomy,” Admiral Girrier told Scout Warrior.

Forward, into Autonomy

Although aerial drones have taken off a lot faster than their maritime and ground-based equivalent, there are some signs that the use of naval drones – especially underwater – is about to take a leap forward. As recently as February this year, U.S. Defense Secretary Ash Carter announced that the Pentagon plans to spend $600 million over the next five years on the development of unmanned underwater systems. DARPA (the Defense Advanced Research Projects Agency) recently announced that the Navy’s newest risk taker is an “unmanned ship that can cross the Pacific.”

DARPA’s initial launch and testing of Sea Hunter. (Video: DARPA via YouTube)

Called the Sea Hunter, the vessel is a demonstrator version of an unmanned ship that will run autonomously for 60 – 80 days at a time. Known officially as the Anti-Submarine Warfare Continuous Trail Unmanned Vessel (ACTUV), the program started in 2010, when the defense innovations lab decided to look at what could be done with a large unmanned surface vessel and came up with submarine tracking and trailing. “It is really a mixture of manned-unmanned fleet,” said program manager Scott Littlefield. The big challenge was not related to programming the ship for missions. Rather, it was more basic – making an automated vessel at sea capable of driving safely. DARPA had to be certain the ship would not only avoid a collision on the open seas, but obey protocol for doing so.

As further evidence of the Navy’s progress toward computer-driven drones, the Navy and General Dynamics Electric Boat are testing a prototype of a system called the Universal Launch and Recovery Module that would allow the launch and recovery of unmanned underwater vehicles from the missile tube of a submarine. The Navy is also working with platforms designed to collect oceanographic and hydrographic information and is operating a small, hand-launched drone called “Puma” to provide over-the-horizon surveillance for surface platforms.

Both DARPA and the Office of Naval Research also continue to create more sophisticated Unmanned Aircraft Systems. DARPA recently awarded Phase 2 system integration contracts for its CODE (Collaborative Operations in Denied Environment) program to help the U.S. military’s unmanned aircraft systems (UAS) conduct dynamic, long-distance engagements against highly mobile ground and maritime targets in denied or contested electromagnetic airspace, all while reducing required communication bandwidth and cognitive burden on human supervisors.

An artist's rendition of DARPA's CODE concept, designed to enable operations in a electromagnetically contested environment. Illustration: DARPA — An artist’s rendition of DARPA’s CODE concept, designed to enable operations in a electromagnetically contested environment. (DARPA)

CODE’s main objective is to develop and demonstrate the value of collective autonomy, in which UAS could perform sophisticated tasks, both individually and in teams under the supervision of a single human mission commander. The ONR LOCUST Program allows UAVs (Unmanned Aerial Vehicles) to stay in formation with little human control. At a recent demonstration, a single human controller was able to operate up to 32 UAVs.

The Networked Machine…

The principle by which individual UAVs are able to stay in formation with little human control is based on a concept called “swarm intelligence,” which refers to the collective behavior of decentralized, self-organized systems, as introduced by Norbert Wiener in his book, Cybernetics. Building on behavioral models of animal cultures such as the synchronous flocking of birds, he postulated that “self-organization” is a process by which machines – and, by analogy, humans – learn by adapting to their environment.

The flock behavior, or murmuration, of starlings is an excellent demonstration of self-organization. (Video: BBC via YouTube)

Self-organization refers to the emergence of higher-level properties and behaviors of a system that originate from the collective dynamics of that system’s components but are not found in nor are directly deducible from the lower-level properties of the system. Emergent properties are properties of the whole that are not possessed by any of the individual parts making up that whole. The parts act locally on local information and global order emerges without any need for external control. In short, the whole is truly greater than the sum of its parts.

There is also a relatively new concept called “artificial swarm intelligence,” in which there have been attempts to develop human swarms using the internet to achieve a collective, synchronous wisdom that outperforms individual members of the swarm. Still in its infancy, the concept offers another approach to the increasing vulnerability of centralized command and control systems.

Perhaps more importantly, the concept may also allay increasing concerns about the potential dangers of artificial intelligence without a human in the loop. A team of Naval Postgraduate researchers are currently exploring a concept of “network optional warfare” and proposing technologies to create a “mesh network” for independent SAG tactical operations with designated command and control.

…And The Connected Human

Adm. Girrier was quick to point out that the strategy – aimed primarily at enabling submarines, surface ships, and some land-based operations to take advantage of fast-emerging computer technologies — was by no means intended to replace humans. Rather, it aims to leverage human perception and cognitive ability to operate multiple drones while functioning in a command and control capacity. In the opinion of this author, a major issue to be resolved in optimizing humans and machines working together is the obstacle of “information overload” for the human.

Rear Admiral Girrier, Director of N99, delivers a presentation on the future of naval unmanned systems at the Center for Strategic and International Studies. — Rear Admiral Robert P. Girrier, Director of N99, delivers a presentation on the future of naval unmanned systems at the Center for Strategic and International Studies, January 29, 2016. See the presentation here. (CSIS)

Captain Wayne P. Hughes Jr, U.S. Navy (Ret.), a professor in the Department of Operations Research at the Naval Postgraduate School, has already noted the important trend in “scouting” (or ISR) effectiveness. In his opinion, processing information has become a greater challenge than collecting it. Thus, the emphasis must be shifted from the gathering and delivery of information to the fusion and interpretation of information. According to CAPT Hughes, “the current trend is a shift of emphasis from the means of scouting…to the fusion and interpretation of massive amounts of information into an essence on which commanders may decide and act.”

Leaders of the Surface Navy continue to lay the intellectual groundwork for Distributed Lethality – defined as a tactical shift to re-organize and re-equip the surface fleet by grouping ships into small Surface Action Groups (SAGs) and increasing their complement of anti-ship weapons. This may be an opportune time to introduce the concept of swarm intelligence for decentralized command and control. Technologies could still be developed to centralize the control of multiple SAGs designed to counter adversaries in an A2/AD environment. But swarm intelligence technologies could also be used in which small surface combatants would each act locally on local information, with systemic order “emerging” from their collective dynamics.

Conclusion

Yes, technology is going to enable increased autonomy, as noted by Adm. Girrier in his interview with Scout Warrior. But as he said, it will be critical to keep the human in the loop and to focus on optimizing how humans and machines can better work together. While noting that decisions about the use of lethal force with unmanned systems will, according to Pentagon doctrine, be made by human beings in a command and control capacity, we must be assured that global order will continue to emerge with humans in control.

Marjorie Greene is a Research Analyst with the Center for Naval Analyses. She has more than 25 years’ management experience in both government and commercial organizations and has recently specialized in finding S&T solutions for the U. S. Marine Corps. She earned a B.S. in mathematics from Creighton University, an M.A. in mathematics from the University of Nebraska, and completed her Ph.D. course work in Operations Research from The Johns Hopkins University. The views expressed here are her own.

Featured Image: An MQ-8B Fire Scout UAS is tested off the Coast Guard Cutter Bertholf near Los Angeles, Dec. 5 2014. The Coast Guard Research and Development Center has been testing UAS platforms consistently for the last three years. (U.S. Coast Guard)

Capability Analysis, Drones

Could Robot Submarines Replace Australia’s Ageing Collins Class Submarines?

April 13, 2016 Guest Author Leave a comment

This article originally featured on The Conversation. It can be read in its original form here.

By Sean Welsh

The decision to replace Australia’s submarines has been stalled for too long by politicians afraid of the bad media about “dud subs” the Collins class got last century.

Collins class subs deserved criticism in the 1990s. They did not meet Royal Australian Navy (RAN) specifications. But in this century, after much effort, they came good. Though they are expensive, Collins class boats have “sunk” US Navy attack submarines, destroyers and aircraft carriers in exercises.

Now that the Collins class is up for replacement, we have an opportunity to reevaluate our requirements and see what technology might meet them. And just as drones are replacing crewed aircraft in many roles, some military thinkers assume the future of naval war will be increasingly autonomous.

The advantages of autonomy in submarines are similar to those of autonomy in aircraft. Taking the pilot out of the plane means you don’t have to provide oxygen, worry about g-forces or provide bathrooms and meals for long trips.

Taking 40 sailors and 20 torpedoes out of a submarine will do wonders for its range and stealth. Autonomous submarines could be a far cheaper option to meet the RAN’s intelligence, surveillance and reconnaissance (ISR) requirements than crewed submarines.

Submarines do more than sink ships. Naval war is rare but ISR never stops. Before sinking the enemy you must find them and know what they look like. ISR was the original role of drones and remains their primary role today.

Last month, Boeing unveiled a prototype autonomous submarine with long range and high endurance. It has a modular design and could perhaps be adapted to meet RAN ISR requirements.

Boeing is developing a long range autonomous submarine that could have military applications.

Thus, rather than buy 12 crewed submarines to replace the Collins class, perhaps the project could be split into meeting the ISR requirement with autonomous submarines that can interoperate with a smaller number of crewed submarines that sink the enemy.

Future submarines might even be “carriers” for autonomous and semi-autonomous UAVs (unmanned aerial vehicles) and UUVs (unmanned undersea vehicles).

Keeping People on Deck

However, while there may be a role for autonomous submarines in the future of naval warfare, there are some significant limitations to what they can achieve today and in the foreseeable future.

Most of today’s autonomous submarines have short ranges and are designed for very specific missions, such as mine sweeping. They are not designed to sail from Perth to Singapore or Hong Kong, sneak up on enemy ships and submarines, and sink them with torpedoes.

Also, while drone aircraft can be controlled from a remote location, telepiloting is not an option for a long range sub at depth.

The very low frequency radio transceivers in Western Australia used by the Pentagon to signal “boomers” (nuclear-powered, nuclear-armed submarines) in the Indian Ocean have very low transmission rates: only a few hundred bytes per second.

You cannot telepilot a submarine lying below a thermocline in Asian waters from Canberra like you can telepilot a drone flying in Afghanistan with high-bandwidth satellite links from Nevada.

Contemporary telepiloted semi-autonomous submarines are controlled by physical tethers, basically waterproof network cables, when they dive. This limits range to a few kilometers.

Who’s the Captain?

To consider autonomy in the role of sinking the enemy, the RAN would likely want an “ethical governor” to skipper the submarines. This involves a machine making life and death decisions: a “Terminator” as captain so to speak.

This would present a policy challenge for government and a trust issue for the RAN. It would certainly attract protest and raise accountability questions.

On the other hand, at periscope depth, you can telepilot a submarine. To help solve the chronic recruitment problems of the Collins class, the RAN connected them to the internet. If you have a satellite “dongle on the periscope” so the crew can email their loved ones, then theoretically you can telepilot the submarine as well.

That said, if you are sneaking up on an enemy sub and are deep below the waves, you can’t.

Even if you can telepilot, radio emissions directing the sub’s actions above the waves might give away its position to the enemy. Telepiloting is just not as stealthy as radio silence. And stealth is critical to a submarine in war.

Telepiloting also exposes the sub to the operational risks of cyberwarfare and jamming.

There is great technological and political risk in the Future Submarine Project. I don’t think robot submarines can replace crewed submarines but they can augment them and, for some missions, shift risk from vital human crews to more expendable machines.

Ordering nothing but crewed submarines in 2016 might be a bad naval investment.

Sean Welsh is a Doctoral Candidate in Robot Ethics at the University of Canterbury. The working title of his dissertation is Moral Code: Programming the Ethical Robot. He spent 17 years working in software engineering for organisations such as British Telecom, Telstra Australia, Fitch Ratings, James Cook University and Lumata. He has given several conference papers on programming ethics into robots, two of which are appearing in a forthcoming book, A World of Robots, to be published by Springer later in the year.

Sean Welsh does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

Featured Image: HMAS Rankin at periscope depth. United States Navy, Photographer’s Mate 1st Class David A. Levy

Drones, Future Tech

A Survey of Missions for Unmanned Undersea Vehicles: Publication Review

June 9, 2015 Guest Author Leave a comment

As a closer to last week’s run of UUV articles – a publication review by Sally DeBoer, UUV week’s associate editor.

Discussion of how the world’s navies will incorporate unmanned underwater vehicles into their doctrine and infrastructure is very broad indeed. Will these technologies be complementary to existing architecture or stand-alone platforms? Will they operate autonomously (indeed, can we even achieve the degree of autonomy required?) or with a man-in-the-loop? Perhaps because the technology is so (relatively) new and (relatively) unestablished, with potential applications so vast, the conversation surrounding it blurs the line between what is and what if.

ums — Conceptualization of the US Navy UUV concept

Thankfully, the meticulous staff at the RAND Corporation’s National Defense Research Institute, sponsored by the US Navy, produced a thorough and carefully researched study in 2009 outlining the most practical and cost-effective applications for underwater technologies. Using the US Navy’s publically-available 2004 UUV Master Plan (an updated version of this document was produced in 2011 but has not been released to the public) as a jumping off point, the authors of the study evaluated the missions advocated for UUVs in terms of military need, technical risks (as practicable), operational risks, cost, and possible alternatives. Analyzing an “unwieldy” set of 40 distinct missions spanning nine categories initially advocated in the 2004 version UUV Master Plan, the study delivers a more focused approach to how the US Navy might best and most effectively incorporate these unmanned systems. Though the UUV Master Plan document is, admittedly, quite out of date (the study itself now more than six years old), the findings therein are still highly relevant to the discussion surrounding the future of unmanned technologies beneath the waves.

Working with the very limited data available on UUVs, the authors of the study considered the technical issues inherent in developing and fielding unmanned underwater systems. Though the full complement of UUV hardware and software is considered in the study, for brevity’s sake this publication review will focus only on two technical factors: autonomy and communications. Intuitively, some missions (such as those of a clandestine or sensitive nature) demand more autonomy than others (like infrastructure monitoring or environmental surveillance). Pertaining to ISR missions, the study suggested that vehicle autonomy limitations would be a significant limiting factor. AUVs may not, for instance, be able to effectively determine what collected information is time-critical and what information is not. This potential weakness could be a tremendous risk; either the notional AUV would fail to transmit information in a timely manner or it would transmit non-useful information needlessly, risking detection and sacrificing stealth. Without significant development, therefore, lack of autonomy would present a technical challenge and, for some advocated missions, an operational risk. In the words of the authors “autonomy and bandwidth form a trade-space in which onboard autonomy is traded for reach-back capability and visa-versa.” The study also addressed perhaps the most frequently cited criticism of UUV technologies: communications and connectivity. Submerged UUVs, the study concludes, are limited in their ability to communicate by “the laws of physics,” while surfaced UUV’s ability to communicate are limited by technology (mast height, data output rates) and present yet another trade-off between stealth and connectivity. These communication systems are, in the words of the authors, considered mature, and are unlikely to be significantly improved by additional research and development.

It’s important to note (and probably obvious to readers) that development of technologies to address the challenges of autonomy and communication for UUV platforms are likely completely opaque to this author. The study’s findings, however, seem to match the challenges the US Navy is facing developing UUVs in the years after its publication. The Office of Naval Research’s Large Displacement Unmanned Underwater Vehicle (LDUUV) program awarded a $7.3 million contract to Metron Inc. to develop and field autonomy software, hardware, and sensors. The LDUUV, a pier-launched system, intended for endurance missions of more than seventy days, will need to effectively avoid interference, requiring a high degree of autonomy. A 2011 Office of Naval research brief envisioned that the LDUUV would “enable the realization of fully autonomous UUVs operating in complex near shore environments” concurrent with the development of “leap ahead” technologies in autonomy. In November of 2014, ONR unveiled a plan to develop an ASW mission package for the LDUUV, pursuing technology development in mission autonomy, situational awareness, and undersea sensors, with emphases on software-in-the-loop and hardware-in-the-loop simulations, and other ASW mission package components. Whether or not intensive R&D will produce the degree of “leap ahead” autonomy necessary for such operations remains to be seen. In the meantime, however, the RAND study’s recommended UUV missions are of particular interest and may dictate the application of funding in a time of scarcity. Put another way, the study’s conclusions provide a cogent and clear roadmap for what the US Navy can do with UUVs as they are and will reasonably become, not how it would like them or envision them to be.

So, then, there is the million (multi-billion?) dollar question: what missions are practically and cost-effectively best suited for UUVs, given these limitations, especially if a mismatch between desired technical functionality and funding and actual ability and allotments continues? The authors suggest (in concurrence with CIMSEC’s own Chris Rawley) that UUV technologies are first and foremost best suited for mine countermeasures, followed in priority by missions to deploy leave-behind sensors, near-land or harbor monitoring, oceanography, monitoring undersea infrastructure, ASW tracking, and inspection/identification in an ATFP or homeland defense capacity. These recommendations are based on already-proven UUV capabilities, cost-effectiveness, and demand. UUVs performing these missions, in particular MCM, have seen steady and

Conceptualization of the Knifefish SMCM UUV System

encouraging progress in the years since the study’s publication. NATO’s Center for Maritime Research and Exploration (CMRE) collected and analyzed data from four UUVs with high-resolution sonar deployed during Multinational Autonomy Experiment (MANEX) 2014. The Littoral Combat Ship’s (LCS) mine-hunting complement includes a pair of Surface Mine Countermeasures (SMCM) UUVs, dubbed Knifefish, that uses its low-frequency broadband synthetic aperture side-scanning sonar to look for floating, suspended, and buried mines and an onboard processor to identify mines from a database. The way ahead for longer-term missions demanding greater autonomy and reach-back over long distances is, for the time being, less clear.

This publication review is truly a very (very!) cursory glance at an incredibly detailed, highly technical study, and in no way does justice to the breadth and depth of the document. I encourage interested readers to download the original .pdf. However, the study’s contributions to an overall understanding of how and where UUVs can practically and cost-effectively support naval operations are significant, effectively reckoning the need to develop cutting-edge technologies with sometimes harsh but ever-present operational and financial realities. UUVs will undoubtedly have a significant role in the undersea battle-space in the years to come; RAND’s 2009 study provides keen insight into how that role may develop.

Sally DeBoer is an associate editor for CIMSEC. She is a graduate of the United States Naval Academy and a recent graduate of Norwich University’s Master of Arts in Diplomacy program. She can be reached at Sally.L.DeBoer(at)gmail(dot)com.

Drones, Future Tech

UUVs as Stealthy Logistics Platforms

June 4, 2015 Guest Author Leave a comment

Guest post for UUV Week by Steve Weintz.

As potential adversaries sharpen their abilities to deny U.S. forces the freedom to maneuver, they concurrently constrain America’s traditional strength in supporting expeditionary power. Sea-bases bring the logistical “tail” closer to the expeditionary “teeth,” but they must stay outside the reach of A2/AD threats. Submarines remain the stealthiest military platform and will likely remain so for some time to come. In addition to their counter-force and counter-logistics roles, subs have seen limited service as stealth cargo vessels. History demonstrates both the advantages and limitations of submarines as transports. Submarine troop carriers, such as those used in SOF operations, are distinct from submarine freighters; the submarine’s role in supply and sustainment is addressed here. Unmanned Underwater Vehicles (UUVs) will revolutionize minesweeping, intelligence collection, and reconnaissance. But they may also finally deliver on the century-old promise of the submarine as a stealthy logistics platform.

Although early submarine pioneers like Simon Lake saw commercial advantage in subs’ ability to avoid storms and ice, submarines as cargo carriers were first used operationally to counter Britain’s A2/AD strategy against Germany in World War I. The Deutschland and her sister boat Bremen were to be the first of a fleet of submarine blockade-runners whose cargo would sustain the German war effort. Despite her limited payload – only 700 tons – the privately-built Deutschland paid for herself and proved her design concept with her first voyage. But the loss of Bremen and America’s turn against Germany scuttled the project.

Cargo subs were again employed in World War II. The “Yanagi” missions successfully transported strategic materials, key personnel, and advanced technology between Germany and Japan. The Japanese also built and used subs to resupply their island garrisons when Allied forces cut off surface traffic. Their efforts met with limited success – enough to continue subsequent missions but not enough to shift the outcome of the Allied strategy. The Soviet Union also used submarines to sustain forces inside denied areas at Sevastopol and elsewhere. These efforts inspired serious consideration of submarine transports that carried over well into the Cold War. Soviet designers produced detailed concepts for “submarine LSTs” capable of stealthily deploying armor, troops and even aircraft.

Dr. Dwight Messimer, an authority on the Deutschland, points out that cargo subs – with one notable exception – have never really surmounted two key challenges. They have limited capacity compared with surface transports, and their cost and complexity are far greater. If subs are made larger for greater capacity, they forfeit maneuverability, submergence speed, and stealth. If built in greater numbers their expense crowds out other necessary warship construction. The Deutschland and Japan’s large transport subs handled poorly and were vulnerable to anti-submarine attacks. Many cargo subs were converted into attack subs to replace attack-sub losses.

The one notable exception to these difficulties is “cocaine subs” so

A "narco-submarine" is apprehended off Honduras — A “narco-submarine” is apprehended off Honduras

frequently encountered by the US Coast Guard. These rudimentary stealth transports are simple and inexpensive enough to construct in austere anchorages, make little allowance for crew comfort, and have proven successful in penetrating denied US waters. The tremendous value of their cargoes means that only a few of these semi-subs need to run the blockade for their owners’ strategy to succeed.

Logistical submarine designers could potentially overcome their two primary challenges by drawing inspiration from smugglers and from nature. UUVs, like other unmanned platforms, enjoy the advantages gained by dispensing with crew accommodations or life-support

equipment. Large UUVs built and deployed in large numbers, like cocaine subs and pods of whales, could transport useful volumes of cargo in stealth across vast distances. MSubs’ Mobile Anti-Submarine Training Target (MASTT), currently the largest UUV afloat, offers a glimpse at what such UUVs might look like. At 60 metric tons and 24 meters in length, MASTT is huge by UUV standards but very small compared to most manned subs.

3D printing technology is rapidly expanding, producing larger objects from tougher, more durable materials. Already, prototype systems can print multistory concrete structures and rocket engines made of advanced alloys. It will soon be possible to print large UUV hulls of requisite strength and size in large numbers. Indeed, printed sub and boat hulls were one of the first applications conceived for large-scale 3D printing. Their propulsion systems and guidance systems need not be extremely complex. Scaled-down diesel and air-independent propulsion systems, again mass-produced, should suffice to power such large UUVs. These long-endurance mini-subs would notionally be large enough to accommodate such power-plants.

10 large UUVs of 30 tons’ payload each could autonomously deliver 300 tons of supplies to forward positions in denied areas. 300 tons, while not a great deal in comparison to the “iron mountain” of traditional American military logistics, is nevertheless as much as 5 un-stealthy LCM-8s can deliver.

A “pod” of such UUVs could sail submerged from San Diego, recharging at night on the surface, stop at Pearl Harbor for refueling and continue on their own to forward bases in the Western Pacific.

Their destinations could be sea-bases, SSNs and SSGNs, or special forces units inserted onto remote islands. Cargoes could include food, ammunition, batteries, spare parts, mission-critical equipment, and medical supplies. In all these cases, a need for stealthy logistics – the need to hide the “tail” – would call for sub replenishment versus traditional surface resupply. Depending on the mission, large UUVs could be configured to rendezvous with submerged subs, cache themselves on shallow bottoms, or run aground on beaches. Docking collars similar to those used on deep-submergence rescue vehicles could permit submerged dry transfer of cargo. UUVs could also serve as stealthy ship-to-shore connectors; inflatable lighters and boats could be used to unload surfaced UUVs at night.

When confronted with anti-submarine attacks a “pod” or convoy of such UUVs could submerge and scatter, increasing the likelihood of at least a portion of their cumulative payload arriving at its destination. Some large UUVs in such a “pod” could carry anti-air and anti-ship armament for defense in place of cargo, but such protection entails larger discussions about armed seaborne drones.

A submarine – even a manned nuclear submarine – is not the platform of choice if speed is essential. Airborne resupply can deliver cargoes much more quickly. But not all cargoes need arrive swiftly. The water may always be more opaque than the sky, and larger payloads can be floated than flown. It remains to be seen if large stealthy unmanned transport aircraft can be developed.

While these notions seem fanciful there is nothing about the technology or the concept beyond the current state of the art. Large numbers of unmanned mini-subs could overcome both the capacity and expense limitations that limited the cargo submarine concept in the past. The ability to stealthily supply naval expeditionary forces despite A2/AD opposition would be a powerful force multiplier.

Steve Weintz is a freelance journalist and screenwriter who has written for War is Boring, io9 and other publications.

Center for International Maritime Security