Toward New Naval Platforms: A Strategic View of the Future of Naval Engineering (2019)

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31 3 Naval Engineering Research and Development The maritime operating environment imposes challenges and requires ca- pabilities that can be especially—and often solely—relevant to the U.S. De- partment of the Navy. It is for this reason that the Office of Naval Research (ONR) is charged with conducting and sustaining basic research aimed at discovering, advancing, and innovating in core areas of naval engineering (NE) that provide unique capabilities critical to the Navy. As the pace of technological change accelerates, however, new science and technology (S&T) developments from outside the core, or traditional, NE fields have the potential to revolutionize and disrupt future naval platforms. A highly effective capability to identify, leverage, and monitor these fast-changing S&T developments has thus become vital to ONR and the Navy. This chapter applies the “lead, leverage, and monitor” construct devel- oped in Chapter 2 to the National Naval Responsibility for Naval Engineer- ing (NNR-NE) program’s research and development (R&D) mission. This first pillar of the program has long consisted of six core NE research areas, each associated with a naval-critical interest or capability. To assume the “lead” in each of these six areas implies that the NNR-NE sets the research scope, priorities, and performance metrics, in addition to providing funding for and active management of the S&T programs. Being the lead also implies that NNR-NE is responsible for sustaining and developing the needed S&T workforce and infrastructure, as the three pillars must function together to ensure that the national NE responsibility is met. Through its leveraging function, the NNR-NE program may make targeted R&D investments to in- crease the applicability of an S&T development to furthering one or more of the lead areas of critical interest. Monitoring S&T developments, including

32 TOWARD NEW NAVAL PLATFORMS those being furthered elsewhere in ONR, implies a level of engagement and attention sufficient to know whether a development may be a candidate for such targeted investments by NNR-NE. Applied to S&T topics in this way, the “lead, leverage, and monitor” framework can be helpful for setting priorities within the NNR-NE S&T portfolio. It can also guide the choices made by ONR when deciding on the content and reach of its NNR-NE S&T portfolio, and it can make the linkages and interdependencies among S&T in core and non-core areas more apparent. In this regard, monitoring and leveraging should not be viewed as low-priority activities, but as functions that are central to the program’s mission. In the next section, the status of NNR-NE’s six core S&T areas, which now constitute the program’s “lead” interests, is summarized with a brief assessment of their relevance to the Navy’s NE enterprise. This is followed by a discussion of the growing imperative for expanding the NNR-NE’s reach to S&T areas outside the traditional bounds of naval engineering. The reasons for this imperative are explained, including the Navy’s expanding concept of what constitutes a “platform” as it places increased emphasis on distributed maritime operations for maintaining naval superiority. Ex- amples are given of S&T areas that could warrant leveraging and monitor- ing to meet this imperative. The chapter concludes by discussing how the diverse requirements of varied naval platforms in the operational concept of distributed maritime operations will drive the demand for innovation from a wide variety of S&T domains, which naval engineering—an inherently multidisciplinary enterprise—can and should be expected to play a central role in fostering. SUMMARY OF THE CURRENT NNR-NE S&T PORTFOLIO The NNR-NE S&T portfolio consists of the following six core topics us- ing the nomenclature of and as described in ONR overview briefings to the committee: 1. advanced naval power 2. hydrodynamics 3. propulsors 4. ship structural reliability 5. control and automation 6. ship design The following sections summarize the main elements of each of these core S&T topics along with committee observations. It merits reiterating that the topics summarized do not include elements of the NNR-NE port- folio that are classified, such as on platform survivability.

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 33 Advanced Naval Power The advanced naval power program focuses on the S&T advances required for integrated platform power systems that can meet the energy demands of advanced directed-energy weapons, more powerful detection systems, electrified propulsion equipment, and unmanned platforms.1 Meeting the demands of many new electrical loads will require major increases in the electric power capacities of future naval platforms.2 Individual research areas cover the following five major topics, the content of which is illustrated by some example topics: 1. Power Generation: fuel cells and fuel reforming, and advanced generators including new features such as superconducting field windings and advanced shipboard turbine engines with higher ef- ficiency and lower emissions. 2. Energy Storage: lithium-ion batteries, ultra-capacitors, and high- speed flywheels. 3. Distribution and Control: AC and DC architectures, high-voltage DC breakers, solid-state transformers, and multi-level power con- verters using wide-bandgap power semiconductor switches. 4. Heat Transfer and Thermal Management: high waste heat removal; advanced chiller technologies; heating, ventilation, and air condi- tioning equipment; forced air and liquid convection; 3D-printed heat exchangers; and heat pipes. 5. Motors and Actuators: high-efficiency, high-speed permanent mag- net and superconducting motors, high-power linear machines for electromagnetic launch and rail guns, carbon nanotube conductors, integrated motor drives, and fault-tolerant machines. The program is designed to address enduring S&T gaps: • High-voltage, high-power DC and AC architectures, including high-voltage DC breakers • High-amplitude, long-duration pulse power delivery capabilities, including energy storage • Platform systems efficiency and energy supply duration to minimize energy resupply 1 H.S. Coombe. Advanced Naval Power. Presentation to the committee, April 2018. See also NPES. 2019. https://www.navsea.navy.mil/Resources/NPES-Tech-Development-Roadmap. 2 In his 2017 white paper The Future Navy, Chief of Naval Operations Admiral John Richardson maintains that “to leave room for future modernization, we should buy as much power capacity as we can afford.” See https://www.navy.mil/navydata/people/cno/Richardson/ Resource/TheFutureNavy.pdf.

34 TOWARD NEW NAVAL PLATFORMS • Power distribution system reconfigurability and survivability to with- stand battle damage/failures • Thermal management to handle high heat fluxes, enabling in- creased power density • On-station autonomous energy harvesting, including wave energy recovery Based on the information provided in the ONR briefings, the advanced power program of NNR-NE is aggressively seeking to fill these S&T gaps through a number of projects. For example, the 12 kV DC architecture that has received considerable attention within the advanced power program hinges critically on the successful development of reliable, compact, and cost-effective DC breakers to protect the DC system against faults caused by equipment failures or battle damage. Likewise, thermal management technologies that take advantage of developments in materials and compact structures are critical to address the increasing demands and complexity of high-energy thermal loads required to meet emerging needs for Navy plat- forms. While the briefing information provided to the committee was not sufficient to judge the extent to which the Advanced Naval Power program is making progress in overcoming major technical challenges and filling critical S&T gaps, these examples illustrates the criticality of ensuring that sufficient resources are devoted to developing and integrating all of the com- ponents that constitute the electrical power systems needed by future naval platforms—a need that is noted when examining the other S&T core areas. Hydrodynamics The hydrodynamics program seeks to understand, characterize, and predict critical physics associated with the design and control of naval platforms.3 The program’s main research areas cover following topics: • Turbulence and Stratified Flow: turbulent flows at high Reynolds number, including non-equilibrium boundary layers and surface roughness, and wake flow physics in a stratified layer • Ship Wave-Breaking and Bubble Wakes: unsteady wake features and mechanisms for naval platforms operating in a relevant sea environment • Submarine Maneuvering and Control: submarine maneuvering performance • Ship Motion and Loads: ship motions and hydrodynamic loads for all ship types in all sea conditions 3 J. Gorski. Hydrodynamic Research Overview. Presentation to the committee, April 2018.

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 35 The research employs a well-established hierarchy of experimental (small, medium, and large scale) and computational approaches (Direct Nu- merical Simulations, Large-Eddy Simulations, Reynolds-Averaged Navier- Stokes Simulations, and potential flow simulations). This program is highly dependent on experimental facilities and advanced computing resources. The study of hull hydrodynamics requires large-scale and specialty labora- tories to understand the complex physics and scaling effects involving mul- tiphase flows and material and structural interactions. While academic labs may be adequate for basic research in this area, only the Navy laboratories can meet these scale and specialization needs. The committee notes that the program has produced a steady improve- ment in understanding of the driving physics, as well as development of pre- dictive hydromechanical models to facilitate design, analysis, and control. The program is also moving toward machine learning. Propulsors The propulsors program seeks to understand, characterize, and predict the governing physics of multiphase flows, propulsor dynamics, and platform interaction to provide advanced naval platforms with quiet, efficient, and affordable propulsor concepts.4 The program’s research areas cover the following four major topics: 1. Modeling of Cavitation and Erosion: advanced measurements tech- nologies and high-fidelity computational tools to study and predict cavitation dynamics and material erosion 2. Propulsor Effects on Underwater Vehicles Dynamics: propeller/ propulsor effects on underwater vehicle dynamics (with focus on crashback and near-surface operations with wave effects), and 6-degrees of freedom dynamics of fully appended underwater ve- hicles with propulsors 3. Advanced Propulsor Concepts: predictive computational tools and experimental studies of advanced propulsor concepts and materials 4. Turbulence Ingestion Sound: turbulence ingestion sound generation mechanism, as well as reliable prediction methods for sound gener- ated by inhomogeneous and non-isotropic turbulence ingested by propulsors The research employs a spectrum of experimental and computational approaches, and thus, like the NNR-NE research on hull hydromechanics, it is highly dependent on experimental facilities and advanced computing 4 K. Kim. Propulsor Research Overview. Presentation to the committee, April 2018.

36 TOWARD NEW NAVAL PLATFORMS resources. The program has yielded steady improvements in understanding of governing physics, as well as furthering the development of predictive capabilities and the exploration of innovative concepts. It has successfully transitioned technology to higher technology readiness levels and to the fleet. Ship Structural Reliability The ship structural reliability program seeks to develop reliability-based knowledge and tools to improve performance and affordability of ship hull structural systems over their full life cycles.5 The program’s research areas cover the following three major topics: 1. Structural Longevity Models: integrated monitoring and predictive models to support operational and maintenance decisions, includ- ing network-based models to fuse measurements with high fidelity simulations and probabilistic optimal planning of structural health monitoring 2. Structural Capability, Degradation, and Repair: composite overlay repair, survivability of degraded or damaged compartments and/or platforms, fatigue life prediction, and stiff anisotropic and adapt- able structures 3. Seaway Load and Structural Response: coupled structural and hydrodynamic modeling, seaway ice impact and structural dam- age prediction, and topside ice accretion performance and stability impact prediction The program’s research, which includes experimental testing and com- putational modeling, has produced steady improvements in the develop- ment of tools to enable reliability-based design and analysis, and support life cycle management and service life prediction and assurance. Some of the tools developed in this program are being used to assess the vulnerability of existing naval platforms and to aid in the design of future naval surface combatants and auxiliaries. The program depends heavily on experimental facilities and advanced computing resources, and some of the major testing relies on overseas facilities and equipment. Control and Automation The control and automation program seeks to aid in the development of un- manned or autonomous surface vessels capable of event-driven operations 5 P. Hess. Ship Structural Reliability Program. Presentation to the committee, April 2018.

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 37 in complex sea environments and swarm maneuvers with other platforms.6 The program’s research covers the following major topics: • Unmanned Surface Vessel Swarm: multi-platform autonomy and self-managed multi-unit task allocation in complex mission environments • Medium Displacement Unmanned Surface Vessel: blue water dem- onstration of prototype vessel (SEA HUNTER developed by the Defense Advanced Research Projects Agency) with minimal remote operator control, and complementary modeling and simulation The ONR briefings on these two program areas centered on the work being undertaken on automation and control, as well as employing at-sea testing, modeling, and simulations. In both program areas, the work is being executed by consortia, whose performers appear to have the needed range and complementarity of expertise. However, it was not apparent from the information provided that the program is furthering unique, new S&T on automation and control. Ship Design The ship design program focuses on (a) developing skilled people and the needed knowledge base and concepts to support future innovative naval technologies, (b) maintaining a workforce pipeline capable of substantive research contributions to the naval research enterprise, and (c) reinvigorat- ing interest in naval-unique research and technology development through topical, short-term innovation cell activities.7 The program’s research con- sists of the following: • Integrated Design and Software Tools: integrate emerging research into multidisciplinary, physics-based design and performance eval- uation tools for advanced naval platforms; translate higher-order physics-based models to fast surrogate models for rapid design and analysis; develop new methods to treat all aspects of design as a variable; develop alternative geometric design representations and analytical techniques to reduce design cycle time and acquisition cost; develop interfaces with proprietary design software to address naval-unique issues such as integration of complex warfighting 6 R. Brizzolara. National Naval Responsibility Naval Engineering: Control and Automation. Presentation to the committee, April 2018. 7 K. Cooper. Sea Warfare and Weapons Department. Presentation to the committee, April 2018.

38 TOWARD NEW NAVAL PLATFORMS systems, large variability in operational profile, and survivability for wartime environments. The program’s focus on the education and development of a U.S. work- force capable of supporting the Navy’s naval engineering is also pursued through means such as Centers for Innovation in Naval Technologies and science, technology, engineering, and mathematics (STEM) activities cen- tered on the science of naval ship design. THE IMPERATIVE OF CAPITALIZING ON S&T ADVANCES OUTSIDE TRADITIONAL NE FIELDS In A Design for Maintaining Maritime Superiority, Version 2.0,8 Chief of Naval Operations (CNO) Admiral John Richardson contends that the fu- ture Navy will be shaped by the increasing use of the maritime domain, the rise of global information systems, and the increasing rate of technological creation and adoption. He stresses the importance of identifying and adopt- ing new and emerging technologies to develop future naval platforms in the face of new extreme operating environments (e.g., arctic, deep sea, surf zone) and new means of operation (e.g., human-in-the-loop, unmanned, and autonomous systems) and to overcome new technological challenges to ensure mission effectiveness, physical and cybersecurity, survivability, sustainability, and cost-effectiveness. These new platforms, he points out, must carry a diverse suite of innovative offensive and defensive capabili- ties, including high-power directed-energy weapons, networked sensors and electronics, and cyber-connected systems with persistent maritime domain awareness. To prepare for this future, in a white paper on The Future Navy, the CNO stresses the importance of the Navy not only having many more naval platforms but also platforms that can incorporate new technologies and new operational concepts.9 He maintains, for instance, that the pace of change also demands that we design ships with modernization in mind. The “core” of those future ships—the hull, and the propulsion and power plants—will likely be built to last for decades. To leave room for future modernization, we should buy as much power capacity as we can afford. On top of that hull and power plant, we must plan from the outset to modernize the “punch”—the combat systems, sensors, and payloads—at the speed that technological advances allow. Future ships should be made for rapid improvement with modular weapons canisters 8 A Design for Maintaining Maritime Superiority, Version 2.0, December 17, 2018. See https://www.navy.mil/navydata/people/cno/Richardson/Resource/Design_2.0.pdf. 9 See https://www.navy.mil/navydata/people/cno/Richardson/Resource/TheFutureNavy.pdf.

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 39 and rapidly swappable electronic sensors and systems. Related, future designs must aggressively go after ways to drive down the costs to operate and maintain the future fleet, no matter its composition. The CNO’s strong views—that the Navy must get started now in think- ing forward and innovating—are consistent with numerous other Navy policy documents that point to the need for the naval R&D enterprise to be responsive to the rapidly evolving physical, operational, and technology environments of future naval platforms. Notably, the new Naval R&D Framework stresses the importance of expanding the technical foundation of Navy research to increase opportunities for cross-discipline innovation and scientific breakthroughs.10 As noted in Chapter 1, the R&D Frame- work is explicit in the expectation that the NNRs will do more than just concentrate on their long-standing S&T topic areas, but also “fast/follow” and “leverage” the S&T advancements from other fields and domains to further those interests and capabilities critical to the Navy and that are central to each NNR’s mission. The NNR-NE program was conceived two decades ago, along with NNRs for other naval-critical interests, to ensure a core capability to support the naval engineering needs of the Navy in the face of decreased budgets and the absence of peer competitors that could risk complacency in technological development. As articulated by Navy leadership in the documents cited earlier, this environment has changed, both because of the accelerating pace of technology development and because of its adaptation by adversaries. Under these changed circumstances, all of the NNRs are expected to adopt a broader view across relevant S&T domains to deliver the advanced technologies required to meet the changing innovation needs of the naval platform concepts that will be the drivers of future force ca- pability. Inasmuch as naval engineering is an inherently platform-centric enterprise, the new expectation of purpose can be viewed as being especially pertinent to the NNR-NE and its capacity to transition and integrate in- novation across the full spectrum of platform-relevant S&T. Having considered the current NNR-NE portfolio of R&D projects, the committee finds no reason to question its relevance to advancing the state of knowledge and technology in each of the six core topic areas. However, one can question whether the R&D portfolio is sufficient to furthering the naval-critical NE interests and capabilities that each of these six core areas represents. In an S&T landscape that is expanding and rapidly changing, the portfolio can address only a slice of the technological spectrum that is radically transforming what is possible and needed for the future Navy. In this environment, an NNR-NE S&T program that is defined by its portfolio 10 See https://www.onr.navy.mil/en/our-research/naval-research-framework, p. 6.

40 TOWARD NEW NAVAL PLATFORMS of R&D projects is too limiting, and in the committee’s view it is in need of a strategic framework for establishing the content of this portfolio and extending its reach. STRATEGIC USE OF THE “LEAD, LEVERAGE, AND MONITOR” FRAMEWORK The committee considered a wide range of S&T fields and disciplines that promise in some way to comprise or influence the NE discipline and naval platform development in the future. While many of these technical areas will have a bearing on a naval-critical NE interest or capability, in only a few of them can, or should, the NNR-NE program “own” the responsibility to shape and sponsor the basic research needed to further the interest or capability. This leadership must be exercised by program managers being attuned to developments in other S&T areas and deliberately leveraging rel- evant technology, as well as by monitoring progress in others, to influence how the lead capabilities should change—for example, by asking questions such as “how can advances in robotics drive changes in platform concepts, structures, and materials?” Other examples of S&T areas where leveraging and monitoring of developments could be useful are corrosion and fatigue control methods, response to extreme wave action, and other structure and equipment design innovations from deepwater facilities, such as offshore energy exploration and production platforms. Thinking along these lines, the committee identified examples, pro- vided here, of technology areas that are candidates for leading, leveraging, and monitoring functions. In using this construct, however, the committee began to question whether the six core, or lead, areas of the NNR-NE are structured and pursued in a manner that renders them too independent from one another, especially given that NE is an inherently inter disciplinary, platform-centric enterprise. The committee did not observe any formal means by which integration occurs at the platform and platform concept levels, where the challenges of NE are manifest due to needs such as in- tegrating complex warfighting systems, ensuring survivability for wartime environments, and accommodating wide variability in operational profiles. Indeed, in its 2019 Naval Power and Energy Systems Technology De- velopment Roadmap, the Navy recognizes that integration of new systems will now be an ongoing challenge throughout a platform’s life cycle in order to maintain warfighting relevancy.11 The roadmap, therefore, calls for a “System Integration Initiative.” Moreover, in addition to technology integration for new platforms, an even more challenging problem may be insertion of new technology into existing platforms, which requires 11 See https://www.navsea.navy.mil/Resources/NPES-Tech-Development-Roadmap.

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 41 multidisciplinary understanding to provide fully capable and affordable integration. For example, adding high-power laser weapon systems requires power generation, storage, and distribution that may not be practical and affordable in existing mechanical platforms. The Naval R&D Framework not only emphasizes that “a more inte- grated approach to research and development (R&D) is needed” (p. 4) but that “affordability permeates all modernization concepts” (p. 20). Because integration is critical to adapting new technologies to existing and new naval platforms, its absence from the NNR-NE core areas is notable. The committee therefore recommends that platform innovations integration and affordability should be added as a new core NNR-NE S&T area for the specific purpose of creating and managing broad platform and multi- platform challenges and designed to identify S&T gaps and opportunities across the technology spectrum (Recommendation 3-1). The addition of this core area would highlight the importance of in- tegrating platform innovations, both within and across platforms, and help stimulate creative and strategic thinking throughout the NNR-NE enterprise to enable, for instance, the fusion of multi-platform solutions that multiply the future combat effectiveness of distributed naval forces. It would keep the NNR-NE program grounded in anticipating and meet- ing the needs of the future Navy, which are—and are likely to remain for some time—platform-centered. It would align with, and be responsive to, the goal outlined in the R&D Framework and Design 2.0 to accelerate technology insertion in existing and future naval platforms. As such, the committee recommends the addition of platform technology integration as an NNR-NE lead research area. It is important to note that this recommen- dation is directly aligned with the recommendation in the Memorandum on National Naval Program for Naval Engineering and the R&D Framework to use the NNR as a core resource to ensure world-class leadership in naval engineering. In considering the six core areas that NNR-NE is charged with leading, the committee also observed that one of the core areas, briefed as “Control and Automation,” is distinct from an interest in “autonomy” and too nar- row and limiting. For instance, the Defense Science Board’s (DSB) Summer Study on Autonomy12 points out that systems governed by prescriptive rules that permit no deviations are auto- mated, but they are not autonomous. To be autonomous, a system must have the capability to independently compose and select among different courses of action to accomplish goals based on its knowledge and under- standing of the world, itself, and the situation. (p. iii) 12 See https://www.acq.osd.mil/dsb/reports/2010s/DSBSS15.pdf.

42 TOWARD NEW NAVAL PLATFORMS A focus on automation, therefore, may neglect S&T relevant to autono- mous capabilities, which the DSB notes is spawning rapid advances in the underlying technology base, driven in large part by the commercial sector. However, even a focus on autonomous capabilities can be too narrow when considered in the context of the Navy’s more encompassing interest in “platform control and maneuverability.” While research on automation may have relevance to this critical interest, basic research is also needed in other areas, for instance, to understand the complex coupled platform motions when performing dynamic maneuvers (e.g., crashback) and con- trol in challenging environments, such as in the Arctic, extreme seas, surf zone, or when cavitation and ventilation are relevant. The committee therefore recommends that ONR should replace “Control and Automa- tion” as a core area of NNR-NE research with “Platform Control and Maneuverability,” a more encompassing interest and one that requires research in many technical areas in addition to automation and autonomy (Recommendation 3-2). While autonomy and robotics are research areas that are vital to the future of naval operations, there is a large amount of R&D investment be- ing made in autonomous systems within the U.S. Department of Defense (DOD) (including other parts of ONR) and the commercial sector. In this instance, it would be appropriate for NNR-NE to deliberately track and seek opportunities to leverage these other efforts to further its critical in- terest in platform control and maneuverability. This leveraging would be consistent with DSB’s recommendation that “DOD take steps to engage non-traditional R&D communities in novel ways to both speed DOD’s access to emerging research results and identify areas in which additional DOD investment is needed to fully address DOD missions” (p. iii). These two recommendations are indicative of how the committee be- lieves the “lead, leverage, and monitor” construct should be used in a strategic manner to guide and give structure to the NNR-NE program and its priorities. They also reflect the committee’s view that naval platforms should be central to each core area, with platforms consisting of far more than just ships. Table 3-1 applies this strategic use of the “lead, leverage, and monitor” framework to a vast set of technical areas, many of which are listed in the leverage and monitor columns. Five of the current six NNR-NE S&T topics are listed in the “lead” column, each renamed to emphasize its relevance to platforms, and they are accompanied by the recommended new “Platform Control and Maneuverability” lead to replace “Control and Automation.” For reasons already explained, autonomy and robotics are relisted as leverage areas. Other topics in the “leverage” column include data science, artificial intelligence (AI), advanced materials, and cybersecurity. These are important examples of S&T topics that are the subject of considerable

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 43 R&D in other sectors, but that bear strongly on the interests of the lead areas. NNR-NE investments that leverage this S&T to make it more ap- plicable and relevant to the needs of a maritime environment may therefore be desirable and worthy candidates for a “leverage” portfolio. A number of other examples of S&T topics that are candidates for leveraging and monitoring are also provided in Table 3-1. The topics listed in the leverage and monitor columns are broadly defined, and in many cases have linkages to more than one of the lead NNR-NE topic areas. Indeed, many of the topics areas listed for monitoring are being led or leveraged by other parts of ONR. The following are three examples of these linkages, and indicative of the type of cross-disciplinary thinking that can offer stra- tegic guidance to NNR-NE in furthering its lead responsibilities. Leveraging Power Electronics and Power Systems for Platform Power and Energy Advanced platform power is a core topic of the NNR-NE program be- cause of the many critical power and energy demands that are specific to naval platforms and unlikely to receive sufficient attention and investment from other sectors. These demands include, for example, the intense, high- frequency energy pulses that will be required in future naval platforms for advanced radar and directed-energy weapons systems. The delivery of these pulse power characteristics will require large amounts of robust, compact energy storage and power distribution equipment and other specialized components that are not likely to be developed unless the Navy takes the lead in supporting the needed R&D. TABLE 3-1 Areas Vital to NNR-NE’s “Lead, Leverage, and Monitor” Responsibilities Lead Leverage Monitor Platform hydrodynamics Platform structures and materials Platform propulsion Platform power Platform systems design Platform control and maneuverability Platform innovations integration and affordability Autonomy and robotics Data science and artificial intelligence Advanced sensors Cybersecurity Communications Power systems and power electronics Advanced materials and manufacturing Multidisciplinary design optimization Human–machine interface Quantum science and computing Alternative energy resources Undersea resource utilization and extraction Nano technology Biomaterials Synthetic biology Cognitive science Climate change

44 TOWARD NEW NAVAL PLATFORMS It is important to recognize, however, that a significant amount of in- vestment is being made by industry in the development of advanced power electronics and power systems for a wide range of industrial and transporta- tion system applications. The Navy can take advantage of these investments to further its critical interest in platform power—for instance, by leveraging the investments made by industry and other federal agencies in areas such as wide-bandgap power semiconductor switches and high-voltage DC power systems. As noted earlier, the Navy needs robust, compact medium-voltage (12 kV) breakers for its future DC power systems. While the breakers are expected to have performance requirements that are far more demanding than those for breakers used for other purposes, NNR-NE investments that leverage the R&D in these other sectors may prove beneficial for making progress in meeting the Navy’s specific performance needs. Leveraging Advanced Materials and Manufacturing and Multidisciplinary Design Optimization for Platform Structures and Materials Platform structures and materials is a core NNR-NE S&T area because of the many naval-specific demands and challenges associated with ship structures and materials, such as stringent limits on vibration and noise and susceptibility to marine growth, sea water corrosion, cavitation erosion, and blast impacts. At the same time, there are clear opportunities for naval platforms to take advantage of the S&T being pursued in other sectors on advanced materials and manufacturing processes and in multidisciplinary design optimization; for instance, to reduce platform design cycle time, lower acquisition cost, and decrease operation and maintenance costs. Examples of S&T advances being pursued elsewhere that pertain to the Navy’s special needs for structures and materials are developments in multi-functional materials and structures that allow on-demand changes according to mission needs, permit self-healing and electro magnetic shielding to enhance survivability, and enable continuous structural health monitoring and damage prognosis. Advances in multidisciplinary design optimization can likewise be used to simultaneously consider the multiple physics arising from competing design requirements, a large number of design variables, and a wide range of operating conditions. In such cases, however, further research is needed to adapt these developments to the special needs of the Navy—for instance, to better understand the behavior of these new structures and materials in the complex maritime environ- ment and the optimal distribution of multi-domain, multi-spectral, multi- modality sensor, control, and operating systems/platforms to facilitate decision-making processes.

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 45 Leveraging Autonomy and Robotics, Data Science and Artificial Intelligence, Advanced Sensors, Cybersecurity, and Communications for Platform Propulsion, Power and Energy, Structures and Materials, Maneuvering and Control, and Hydrodynamics Many of the example S&T topics listed in the “leverage” column of Table 3-1 would have relevance to a number of the NNR-NE’s core or lead interests, especially when considered in the context of platform-specific needs. To illustrate, consider the performance and capability requirements of autonomous amphibious vehicles. These vehicles must meet the payload, endurance, and survivability requirements of a diversity of naval mis- sion demands. They must have the ability to communicate, keep position (station-keep), and form coordinated maneuvers with other platforms. They must traverse from deep water to the turbulent, noisy, and obstacle-laden environment of the surf zone (with large breakers, turbulent bores, strong currents, and suspended sediments). They must be able to traverse from the surf zone to uneven and mobile grounds. The varied and demanding performance requirements of autonomous amphibious vehicles present numerous challenges relevant to NNR-NE’s core S&T areas. For example, the vehicles require advances in power and energy and in structure and materials to provide the needed light weight, high strength, and high energy density. They require advances in propulsion and control for station-keeping and low-speed and coordinated maneuver- ing. Hydrodynamic challenges include complex multiphase flow dynamics, including ventilation, cavitation, and interaction with free surface, waves, and currents. While the NNR-NE’s core areas are addressing some of these challenges, they will clearly require S&T advances from other areas, such as advancements in sensors, autonomy and robotics, artificial intelligence, cyber–physical security, and communications. By leading, leveraging, and monitoring developments from such a diverse range of S&T areas, cogni- zant of the platform-specific requirements of the Navy, the NNR-NE could fulfill an essential integration role that is in many respects the hallmark of the multi- and interdisciplinary field of naval engineering. These three examples of how the NNR-NE program can lead and leverage S&T to enable the Navy to be a more agile adopter of emerging technologies illustrates why it is so important, in the committee’s view, for NNR-NE’s S&T portfolio to be shaped in a strategic manner that gives explicit consideration to where the program is best suited to leading, lever- aging, and monitoring. While opportunities for monitoring were not dis- cussed in the foregoing examples, Table 3-1 provides a number of candidate topic areas. In such instances, one would expect the NNR-NE to make the investments needed to ensure the S&T areas are monitored sufficiently to know when some may be deserving of leveraging investments. Indeed, S&T

46 TOWARD NEW NAVAL PLATFORMS topics listed in the leverage and monitoring columns are examples, and not intended to be a prioritization. Given the fast pace of technological change, it is reasonable to expect that S&T topics will need to be shifted among the two columns—necessitating frequent reviews of the coverage and linkages of content in the NNR-NE portfolio. Figure 3-1 shows how leveraged and monitored technologies may have application to multiple lead responsibili- ties. NNR-NE’s integration of a leveraged technology may, in turn, create new demands for research such as on novel system architectures and new methods for technology insertion, maintenance, and repair. In the committee’s view, ONR should adopt a “lead, leverage, and monitor” framework for prioritizing, programming, and integrating NNR-NE’s S&T investments. This framework should be used not only to guide decisions about critical naval engineering interests that require NNR-NE’s lead support for S&T but also to identify S&T from outside the program that can be leveraged to further these critical interests (Rec- ommendation 3-3). VIEWING PLATFORMS AS INNOVATION “FORCING” For now and into the foreseeable future, the Navy will operate from a platform-centric perspective. However, as new technology shapes the future force, the very concept of a naval platform can be expected to change to encompass groups of technologies that form a deployable base for combina- tions of hardware, software, and human systems that together can deliver a desired military capability and effect when operating individually or net- worked with other such naval platforms. Examples include cyber-connected autonomous vehicles, manned-unmanned teams of surface vehicles, ships, submarines, amphibious craft, and even ground vehicles. While the defini- tion of a platform may be changing and expanding as the Navy migrates FIGURE 3-1 Potential linkages between leverage and monitor areas and NNR-NE lead areas.

NAVAL ENGINEERING RESEARCH AND DEVELOPMENT 47 to a more heterogeneous and distributed force, the U.S. naval capability ultimately lies in the platforms that are deployed and the personnel that design, build, and operate them. It is for this reason that the committee has recommended that the NNR-NE’s core S&T responsibilities be expanded to include a platform innovations integration program to facilitate broader academic, government, and industry interaction on future force system integration. In the committee’s view, the addition of “platform innovations integration and affordability” as a lead NNR-NE research area would be an important first step to ensuring that NNR-NE R&D is addressing the platform-driven innovation needs of the future Navy. Each platform concept creates different challenges and demands for innovations; for instance, to expand use into new operational domains, reduce manning, provide quieter and faster operations, accommodate new weapon and sensory systems concepts, and accelerate design, build, and acquisition cycles. Not only does each platform concept have requirements that present specific S&T challenges, but these challenges must be met by employing innovations from across the technology spectrum and with a high degree of integration. In developing this recommendation, it occurred to the committee that the needs of future platforms are, in essence, the forcing function for naval innovation and that naval engineering is central to designing, integrating, and delivering these innovations to the expanding array of platforms that will underpin future Navy superiority. An example of a platform forcing function is the increasingly complex littoral and confined domains in which naval platforms must operate, which creates new paradigms in platform designs, operations, and manning. Another more futuristic example is to conceptualize a next generation submarine with a crew size that is half the size of today’s submarines, which would radically influence the design of the platform to create new tradeoffs in size, speed, payload, etc., as well as new technology gaps and opportunities. This platform concept might, for instance, compel the substitution of autonomy for human operators or human-in-the-loop systems in all routine functions and even the devel- opment of self-healing machinery components tied into an AI model of the ship. As it periodically reviews the coverage, relevance, and linkages of the S&T that it leads, leverages, and monitors, NNR-NE should adopt a platform-centric approach to identifying innovation needs, challenges, and opportunities. Informed by the promise of the technologies that it leads, leverages, and monitors, NNR-NE should be anchored by a strategic vi- sion of naval platforms 20 to 30 years out (Recommendation 3-4). Such an approach could lead to the identification of new areas of S&T that are now missing from the NRR-NE portfolio. For example, a new challenge might be in furthering the understanding of and capabilities to measure,

48 TOWARD NEW NAVAL PLATFORMS characterize, and predict local platform environments that require consid- eration of the highly nonlinear processes and coupled interactions involving waves, currents, turbulence, bottom and boundary topographies, and pos- sibly near-surface winds (all of which can affect the operational feasibility and envelope, as well as safety and even survivability, of the platforms). While not traditionally within the purview of naval engineering, in terms of extension of operational domain and capabilities, leadership in the core area of local platform environment could create a significant competitive advantage for the future Navy. While an approach for programming NNR-NE that views platforms as “innovation forcing” would necessarily emphasize the importance of ensuring the accelerated introduction and applicability of technology, it might also be construed as placing resource pressures on basic research, from which many of the technological advances cited in this chapter and report have their roots. The recommended “lead, leverage, and monitor” framework, however, should imply that ONR sustain the basic research in its lead core areas. To ensure that a platform-centric approach to S&T programming does not erode this critical ONR responsibility, the commit- tee recommends that NNR-NE maintain a strong focus on basic research in its lead core areas. This NE research should continue to be viewed as the key building block for the future Navy (Recommendation 3-5).