The U.S. Navy has long relied on underwater stealth to ensure dominance at sea while influencing events ashore. The superiority our submarines afford has been impressive, but our preeminence beneath the waves is continually contested, as nations worldwide expand their capability in that domain. The same attributes contributing to our advantage in that realm now favor adversaries. As foreign spending and proliferating technologies increase our foes’ potential, we must seek innovative systems to meet and overcome asymmetric undersea threats.
The Navy historically has evolved to meet emerging challenges. That evolution continues. A new “Undersea Dominance” strategy will harness information so we can prevail in the maritime domain. The new strategy will provide a continuum of undersea-sensing capabilities delivered through an integrated communication architecture derived from investment in innovative technology and applications. To create strategic opportunity and extend operational advantage, the Navy is examining key doctrinal, training, and maintenance solutions as well as technological opportunities to add to that continuum, facilitating extraction of critical subsurface information for the warfighter. A key component of that strategy will be advanced unmanned undersea systems (UUSs).
Why Unmanned?
The primary attributes of unmanned undersea systems are their stealth and autonomy to execute what are often called the “dull, dirty, and dangerous” tasks. During pre-hostilities, such systems can gain knowledge of potential future operating environments—preparing the battlefield. In times of rising tension, UUSs can continue to provide timely information in a manner less provocative than a manned platform, allowing decision-makers to de-escalate, if necessary, without a highly visible presence. During hostilities, UUSs can provide information or take action to minimize risk to manned platforms while simultaneously freeing those more flexible assets for complex operations.
Across all of those environments, UUSs provide endurance unfettered by crew and platform limitations. Unlike a human crew, the autonomous UUS can be as capable and alert sixty hours—or five weeks—into the operation as it was when the operation started. It knows neither fatigue nor complacency. Within those systems, a key component will be unmanned underwater vehicles. UUVs will operate with manned, fixed, and mobile sensors to facilitate undersea information dominance supporting Navy and joint operations at sea and across the beach ashore.
Legacy UUVs
The Navy’s history with UUVs stretches back several decades. Working with the Defense Advanced Research Projects Agency and commercial industry, it developed a number of UUVs keyed to specific missions. Absent a single advocate unifying the various systems, specific capability was developed in multiple-mission areas, including mine warfare, oceanography, special warfare, and intelligence preparation of the battlespace. Personal and professional relationships—spanning laboratories, engineering teams, and a limited field of military operators—knit the community together.
By the 1990s, vehicles were being developed across a wide range of sizes and forms. Early efforts to guide technology development were embodied first in the 1994 Navy UUV Program Plan, followed by the Navy’s UUV Master Plan, initially issued in 2000 and updated in 2004. The 2004 plan began to standardize development into four basic sizes by diameter (in inches) and weight (in pounds): man-portable (3-inch to 9-inch and less than 100 lbs.); lightweight (12.75 inches, roughly 500 lbs); heavyweight (21 inches, less than 3,000 lbs.); and large (greater than 36 inches, up to 20,000 lbs.).
Many of the systems developed in the first couple of decades employed small man-portable vehicles. They were ideal for applications in which operators could be in relatively close proximity to the operations, and long endurance was not a primary performance attribute. For long-range missions, high-energy-consumption missions were not anticipated to last much beyond 12-13 days. The absence of an ultra-long-endurance energy source led to concepts employing host platforms. The naval oceanographic community’s USNS Pathfinder-class of survey ships performed this function for the large Seahorse UUVs, while heavyweight vehicles were developed for submarines to use the only force-wide common ocean interface—the 21-inch torpedo tube.
Limited energy, relatively rudimentary autonomous data-processing, and disadvantaged communications with limited bandwidth argued for a host platform to which a UUV could return, dump its stored data, and recharge its batteries before being redeployed. In that context, UUVs were viewed as an off-board extension of the host platform—an extension of the “field of regard.” Early efforts yielded a fair number of lessons learned. For instance, while submarine torpedo-tube launch was relatively simple, reliable recovery back into a torpedo tube was highly problematic. While technically viable methods were demonstrated across several programs, and successes were achieved, the aggregation of individual technical, programmatic, and operational issues reached critical mass in late 2008, prompting a “strategic pause” in acquisition-program development of most 21-inch and larger UUVs.
At the same time, commercial applications for UUVs continued to evolve. Environmental monitoring, gas- and oil-field survey, and oceanographic/climatic research are just a few areas in which UUVs gained a foothold. Advances in commercial sensors and sonar, as well as navigational instruments (inertial systems, velocimeters, and global positioning systems) provided dual-use capability improvements with direct application to military UUVs. However, some of the advances in critical areas—vehicle endurance, communication, and vehicle/mission autonomy—shown to be fully adequate for commercial or academic use were not sufficient to meet undersea military requirements. The continued capability limitations in key areas left the Navy rightfully thinking, “Unmanned underwater vehicles for what? There is no military ‘killer app’ for UUVs. They’ve been an interesting excursion, but just don’t have any tactical utility.”
What Has Changed
As we enter the second decade of this century, a number of factors have converged to alter the landscape as the Navy emerges from its UUV strategic pause. There is acknowledgement that our capacity gap—complicated by fiscal pressures on major manned platforms—can be partially mitigated with unmanned systems. As a result, the Navy has been aggressively reengaging with the assistance of teams such as the CNO’s Strategic Studies Group, Navy Warfare Doctrine Command, Navy Mine and ASW Command, the Office of Naval Research, Navy’s Warfare Centers, and the Naval Postgraduate School. The result is a body of intellectual work articulating how unmanned systems will augment manned assets in the naval battlespace. While we may not yet have defined that killer app, we are seeing a number of valid naval applications. In the undersea realm, the way ahead is consolidating around a multimission, reconfigurable, long-duration, and large-displacement UUV—an LDUUV.
The principal element driving the renewed emphasis is long-endurance energy. The Office of Naval Research is leading the development of systems capable of providing tactically relevant endurance. An ONR Industry Day in February 2011 identified notional power profiles and desired system features. Recognizing that batteries alone cannot meet the energy goals, a variety of technologies—from fuel cells to hybrid systems—are being explored. That effort is key to moving UUSs forward.
Second, advances in computer processors for speed, throughput, and reduced power consumption will allow the highly complex vehicle and mission autonomy necessary to execute very-long-endurance missions. As the on-board “intelligence” is better able to evaluate and filter received data, turning it into actionable information for the warfighter, the need for high-volume communications can be reduced, with concurrent reduction in detectability and conservation of energy previously dedicated to data transmission. The inherent difficulty of communicating with a submerged system at any significant distance argues for a high degree of autonomy. Unlike an unmanned aerial vehicle, it is not feasible to routinely “joy-stick” UUVs during operations.
Third, though pier-to-pier operations that support manned platforms without burdening a host platform are preferred, a new generation of warships both on and under the sea will provide vessel interfaces for LDUUVs, making launch and recovery operations from a host less cumbersome. As already demonstrated from existing Ohio-class hulls prior to the SSGN conversions, LDUUVs are a viable option. Similarly, whereas unmanned vehicles were add-on alterations to previous surface combatants (e.g., the remote mine-hunting system on destroyers), the littoral combat ship is the ideal platform to use off-board vehicle capability.
Finally, it is crucial that we have a strategic framework in which unmanned vehicles are not merely pieces of hardware or sensors sent off-board, but actual providers of information feeding a network that enhances situational awareness and facilitates precise force application. Earlier, the lack of a unifying Navy-wide vision put into practice through a Fleet-generated and approved concept of operations led to the “UUVs for what?” question. Today’s holistic approach to consolidating sponsorship within the information-dominance community has formed an intellectual continuum for delivering the needed undersea system. Every unmanned vehicle must be a node, and every node must feed into the information grid.
‘Where Do We Go From Here?’
Given the renewed focus on integrated operational applications and the need to fill capacity gaps brought about by force-structure fiscal constraints, where do we go from here? First and foremost, efforts that are working—such as oceanographic gliders and mine warfare UUVs—must continue. We must not derail effective programs. However, there is a potentially significant opportunity for some advances developed for LDUUV to be folded back into existing systems (and their successors) to further enhance effectiveness. Within that context, how do we achieve the unmanned imperative?
We must define an achievable increment of military capability backed with sound operational concepts. To use an aviation analogy, UUVs are probably somewhere between a 1940s propeller-driven aircraft and an early jet fighter—depending on the task application and mission complexity. Some systems are still fairly rudimentary, but advances are being incorporated. We cannot expect the performance of an SR-71 Blackbird or F/A-18 Hornet the first time out.
So we must be judicious about how we apply resources. Significant sums have been applied across a wide range of component-technology projects in the past, yielding strides in a number of the areas mentioned here. But prior efforts—often uncoordinated—failed to mainstream UUV system capability. To do that, the Navy needs to set realistic capability requirements, employ “good enough” technology, and accept that subsequent increments of improvement can be spiraled into the systems. Once system requirements and standards are set, they cannot be allowed to expand, causing delays. Instead, we must deliver real capability to Fleet operators, providing real information to front-line units and decision makers. The overall recommendation of the UUV Master Plan from 2004 remains pertinent today: “Deliver UUV capability . . . and begin using it!”
Setting Priorities
To do so, we have to determine what our cost-drivers have been and separate “nice-to-have” from “absolutely-must-have” technologies. Just as requirements appetites must be constrained, the same must be done with technology to meet the requirements. The most urgent technology in the “must-have” category is reliable energy, providing tactically relevant capability while allowing for safety certification for use from shore, from surface ships, and from submarines (but not necessarily from all of those, initially).
Without a long-endurance energy source, the tactical utility of UUVs is diminished as host platforms incur operational penalties to “service” the vehicles for energy, payload data download, or both. Ideally, UUVs will possess sufficient capability and reliability to be launched from shore sites, transit autonomously, execute their tasking while providing their mission intelligence in a netted-information system, and return home autonomously without any impact on the manned platforms that they are supporting.
Next, architectures must be standardized for sufficient vehicle and mission autonomy, information assurance/antitamper, and command and control. Those architectures must be open and severable to facilitate incremental software and safety certification of follow-on developments. The modular LDUUV hull must incorporate sufficient growth margin to accept new payloads, rather than requiring development of whole new systems. The payload mantra must be “Modular, Scalable, Plug & Play.” Within the architectures, standards for physical and software interfaces, information-exchange formats, and planning-and control-functions must be set and disseminated. Common control for unmanned vehicles is evolving within the UAV community, and the undersea community cannot be separate from that effort. There can be no tolerance for system-unique control boxes carried onto host platforms for any unmanned system. Such an approach carries too high a burden in space, weight, and power for the host, as well as the training, maintenance, and repair costs for the logistics community.
Underpinning all the technology and architecture aspects, the fielding framework—from the overarching operational employment and tasking concepts to application of tactical sensors—must be developed, modeled, simulated, and war-gamed to determine the best mix of unmanned capability to optimize manned platforms. The doctrinal and procedural maturity of the air-warfare commander must be equaled by the maturation of the undersea-warfare commander using unmanned subsurface systems to deliver the information necessary to attain and maintain dominance.
Finally, we cannot forget that the unmanned system includes the back-end efforts of information processing, exploitation, and data dissemination. Proliferation of sensors acting as information nodes, grouped with increased endurance and commensurate time-on-station will result in exponential growth in raw data collected. Increased manpower to analyze this flood of data is not the answer. Instead, data must be autonomously assessed and filtered by on-board processors. Useful information must then be fed into secure joint cloud-computing environments from which multiple consumers may pull applicable information.
A Future Vision
Decades from now, UUSs will be real and prolific. They will be another arrow in the Fleet commander’s quiver. Innovative application of technological advances will force that reality. The question is not whether it will happen, but how we will lead that march. A force composed of all manned or all unmanned platforms is precisely wrong. Somewhere between those two extremes, a proper capability balance exists. That balanced mix must be determined. However, we cannot wait for a completely refined answer before we begin fielding capability. Focus on developing the capability while that determination is in progress—because without doubt we will be going there. The Navy must continue to develop the family of undersea systems that truly makes information beneath the waves a main battery in our warfighting capability arsenal.
Those systems, of which UUVs will be a crucial component, will enhance the already impressive capabilities of our manned platforms. The information provided to our warfighters may not make the oceans transparent—but it will make the undersea picture much clearer for our forces, ensuring continued dominance there.
Killer what?
A “killer application”—usually just “killer app”—is techno-jargon for a computer application program that shows itself to be so necessary or desirable that it leads consumers to purchase the system that runs it—a computer, gaming console, or operating system. Spreadsheet software, for example, was a killer app, leading to the widespread use of personal computers in the workplace.