Checking an aircraft for damage can be arduous and meticulous work, but last week’s issue of The Economisthighlights an experimental commercial approach. In simple terms, the Remote Intelligent Survey Equipment for Radiation (RISER) drone is a quadcopter with LIDAR and forms the basis for a system to use lasers to automatically detect damage to airliners.
The obvious naval application for inspector drones would be for ground-, carrier, and surface vessel-based fixed-wing and helicopter units, although the configurations for each aircraft type and location might make some more practical than others. For example it probably makes more sense to consolidate expertise in inspector drones at regional maintenance and readiness centers than to try to outfit a unit in the small helicopter hangar of every destroyer. But there’s always something to be said for an operational capability.
While The Economist notes that the drones are allowed at Luton airport, UK, to “operate only inside hangars, and only when the doors are shut,” similar systems could be used during periods of extended surface ship and submarine maintenance, particularly while in dry dock to check for damage and wear and tear to those vessels’ hulls and systems.
We’ve speculated previously at CIMSEC on the utility of LIDAR-equipped shipboard robots and autonomous systems to engage in damage control, but external hull and airframe inspection drones add a wrinkle and join an ever-growing list of potential (and actualized) uses for drones.
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.
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 $7.3million 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
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.
Should robots sink ships with people on them in time of war? Will it be normatively acceptable and technically possible for robotic submarines to replace crewed submarines?
These debates are well-worn in the UAV space. Ron Arkin’s classic work Governing Lethal Behaviour in Autonomous Robots has generated considerable attention since it was published six years ago in 2009. The centre of his work is the “ethical governor” that would give normative approval to lethal decisions to engage enemy targets. He claims that International Humanitarian Law (IHL) and Rules of Engagement can be programmed into robots in machine readable language. He illustrates his work with a prototype that engages in several test cases. The drone does not bomb the Taliban because they are in a cemetery and targeting “cultural property” is forbidden. The drone selects an “alternative release point” (i.e. it waits for the tank to move a certain distance) and then it fires a Hellfire missile at its target because the target (a T-80 tank) was too close to civilian objects.
Could such an “ethical governor” be adapted to submarine conditions? One would think that the lethal targeting decisions a Predator UAV would have to make above the clutter of land would be far more difficult than the targeting decisions a UUV would have to make. The sea has far fewer civilian objects in it. Ships and submarines are relatively scarce compared to cars, houses, apartment blocks, schools, hospitals and indeed cemeteries. According to the IMO there are only about 100,000 merchant ships in the world. The number of warships is much smaller, a few thousand.
There seems to be less scope for major targeting errors with UUVs. Technology to recognize shipping targets is already installed in naval mines. At its simplest, developing a hunter-killer UUV would be a matter of putting the smarts of a mine programmed to react to distinctive acoustic signatures into a torpedo – which has already been done. If UUV were to operate at periscope depth, it is plausible that object recognition technology (Treiber, 2010) could be used as warships are large and distinctive objects. Discriminating between a prawn trawler and a patrol boat is far easier than discriminating human targets in counter-insurgency and counter-terrorism operations. There are no visual cues to distinguish between regular shepherds in Waziristan who have beards, wear robes, carry AK-47s, face Mecca to pray etc. and Taliban combatants who look exactly the same. Targeting has to be based on protracted observations of behaviour. Operations against a regular Navy in a conventional war on the high seas would not have such extreme discrimination challenges.
A key difference between the UUV and the UAV is the viability of telepiloting. Existing communications between submarines are restricted to VLF and ELF frequencies because of the properties of radio waves in salt water. These frequencies require large antenna and offer very low transmission rates so they cannot be used to transmit complex data such as video. VLF can support a few hundred bits per second. ELF is restricted to a few bits per minute (Baker, 2013). Thus at the present time remote operation of submarines is limited to the length of a cable. UAVs by contrast can be telepiloted via satellite links. Drones flying over Afghanistan can be piloted from Nevada.
For practical purposes this means the “in the loop” and “on the loop” variants of autonomy would only be viable for tethered UUVs. Untethered UUVs would have to run in “off the loop” mode. Were such systems to be tasked with functions such as selecting and engaging targets, they would need something like Arkin’s ethical governor to provide normative control.
DoD policy directive 3000.09 (Department of Defense, 2012) would apply to the development of any such system by the US Navy. It may be that a Protocol VI of the Convention on Certain Conventional Weapons (CCW) emerges that may regulate or ban “off the loop” lethal autonomy in weapons systems. There are thus regulatory risks involved with projects to develop UUVs capable of offensive military actions.
Even so, in a world in which a small naval power such as Ecuador can knock up a working USV from commodity components for anti-piracy operations (Naval-technology.com, 2013), the main obstacle is not technical but in persuading military decision makers to trust the autonomous options. Trust of autonomous technology is a key issue. As Defense Science Board (2012) puts it:
A key challenge facing unmanned system developers is the move from a hardware-oriented, vehicle-centric development and acquisition process to one that addresses the primacy of software in creating autonomy. For commanders and operators in particular, these challenges can collectively be characterized as a lack of trust that the autonomous functions of a given system will operate as intended in all situations.
There is evidence that military commanders have been slow to embrace unmanned systems. Many will mutter sotto voce: to err is human but to really foul things up requires a computer. The US Air Force dragged their feet on drones and yet the fundamental advantages of unmanned aircraft over manned aircraft have turned out to be compelling in many applications. It is frequently said that the F-35 will be the last manned fighter the US builds. The USAF has published a roadmap detailing a path to “full autonomy” by 2049 (United States Air Force, 2009).
Similar advantages of unmanned systems apply to ships. Just as a UAV can be smaller than a regular plane, so a UUV can be smaller than a regular ship. This reduces requirements for engine size and elements of the aircraft that support human life at altitude or depth. UAVs do not need toilets, galleys, pressurized cabins and so on. In UUVs, there would be no need to generate oxygen for a crew and no need for sleeping quarters. Such savings would reduce operating costs and risks to the lives of crew. In war, as the Spanish captains said: victory goes to he who has the last escudo. Stress on reducing costs is endemic in military thinking and political leaders are highly averse to casualties coming home in flag-draped coffins. If UUVs can effectively deliver more military bang for less bucks and no risk to human crews, then they will be adopted in preference to crewed alternatives as the capabilities of vehicles controlled entirely by software are proven.
Such a trajectory is arguably as inevitable as that of Garry Kasparov vs Deep Blue. However in the shorter term, it is not likely that navies will give up on human crews. Rather UUVs will be employed as “force multipliers” to increase the capability of human crews and to reduce risks to humans. UUVs will have uncontroversial applications in mine counter measures and in intelligence and surveillance operations. They are more likely to be deployed as relatively short range weapons performing tasks that are non-lethal. Submarine launched USVs attached to their “mother” subs by tethers could provide video communications of the surface without the sub having to come to periscope depth. Such USVs could in turn launch small UAVs to enable the submarine to engage in reconnaissance from the air. The Raytheon SOTHOC (Submarine Over the Horizon Organic Capabilities) launches a one-shot UAV from a launch platform ejected from the subs waste disposal lock . Indeed small UAVs such
as Switchblade (Navaldrones.com, 2015) could be weaponized with modest payloads and used to attack the bridges or rudders of enemy surface ships as well as to increase the range of the periscope beyond the horizon. Future aircraft carriers may well be submarine.
In such cases, the UUV, USV and UAV “accessories” to the human crewed submarine would increase capability and decrease risks. As humans would pilot such devices, there are no requirements for an “ethical governor” though such technology might be installed anyway to advise human operators and to take over in case the network link failed.
However, a top priority in naval warfare is the destruction or capture of the enemy. Many say that it is inevitable that robots will be tasked with this mission and that robots will be at the front line in future wars. The key factors will be cost, risk, reliability and capability. If military capability can be robotized and deliver the same functionality at similar or better reliability and at less cost and less risk than human alternatives, then in the absence of a policy prohibition, sooner or later it will be.
Sean Welsh is a Doctoral Candidate in Robot Ethics at the University of Canterbury. His professional experience includes 17 years working in software engineering for organizations such as British Telecom, Telstra Australia, Fitch Ratings, James Cook University and Lumata. The working title of Sean’s doctoral dissertation is “Moral Code: Programming the Ethical Robot.”
Arkin, R. C. (2009). Governing Lethal Behaviour in Autonomous Robots. Boca Rouge: CRC Press.
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
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.
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