1

Introduction

The challenge of undersea warfare is not widely appreciated. In the atmosphere, objects are generally visible, locatable, and identifiable. Electromagnetic radiation is reflected, refracted, and absorbed to a manageable extent. The boundaries do not cause major problems. The movement of platforms and projectiles is not greatly impeded by the medium. Electromagnetic emissions from sources occur at the speed of light, resulting in high data rates, which facilitate detection, classification, localization, and engagement.

By comparison, the underwater challenge in these respects is limited by the speed of sound in seawater. Radiation is strongly absorbed and redirected at boundaries. Deep water provides cover. Acoustic methodology has long been of paramount importance in deep water, and although the environment is relatively well understood, it is complicated. Near-shore waters (the littorals) are essential battle spaces for extending a force, but the challenges are enormous and not well characterized in terms of science or terrain. Uncertainty is common. Acoustic signals respond to all manner of (often unknown) boundaries associated with shallow water, traffic, debris, gradients, and the like. The encounter distances may be short. Water absorbs radiation directly and is often murky besides.

The physics of the undersea environment is probably understood in general terms, but coupling this understanding to practical use is difficult. New physics and new applications will emerge to the benefit of nations that pursue the basic science. A broadening of sensor technology is inevitable. Chemistry will be exploited. It is in this domain of open-ended science and technology (S&T) that the Office of Naval Research (ONR) can make a unique contribution by identifying, initiating, and enabling future opportunities, missions, capabilities, and solutions.

The Department of the Navy's undersea weapons S&T program resides at ONR and addresses primarily torpedo-related issues. The Department's inventory of weapons that spend some time undersea includes mine-like torpedoes (e.g., fixed and mobile mines such as the CAPTOR mine, which is an encapsulated torpedo), the submarine-launched mobile mine, and the ASROC antisubmarine rocket-propelled torpedo launched vertically from a surface ship, as well as strike weapons such as the Tomahawk missile, launched from a submerged submarine. At the sponsor's request and with the concurrence of the Committee for Undersea Weapons Science and Technology, this assessment focused on that



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An Assessment of Undersea Weapons Science and Technology 1 Introduction The challenge of undersea warfare is not widely appreciated. In the atmosphere, objects are generally visible, locatable, and identifiable. Electromagnetic radiation is reflected, refracted, and absorbed to a manageable extent. The boundaries do not cause major problems. The movement of platforms and projectiles is not greatly impeded by the medium. Electromagnetic emissions from sources occur at the speed of light, resulting in high data rates, which facilitate detection, classification, localization, and engagement. By comparison, the underwater challenge in these respects is limited by the speed of sound in seawater. Radiation is strongly absorbed and redirected at boundaries. Deep water provides cover. Acoustic methodology has long been of paramount importance in deep water, and although the environment is relatively well understood, it is complicated. Near-shore waters (the littorals) are essential battle spaces for extending a force, but the challenges are enormous and not well characterized in terms of science or terrain. Uncertainty is common. Acoustic signals respond to all manner of (often unknown) boundaries associated with shallow water, traffic, debris, gradients, and the like. The encounter distances may be short. Water absorbs radiation directly and is often murky besides. The physics of the undersea environment is probably understood in general terms, but coupling this understanding to practical use is difficult. New physics and new applications will emerge to the benefit of nations that pursue the basic science. A broadening of sensor technology is inevitable. Chemistry will be exploited. It is in this domain of open-ended science and technology (S&T) that the Office of Naval Research (ONR) can make a unique contribution by identifying, initiating, and enabling future opportunities, missions, capabilities, and solutions. The Department of the Navy's undersea weapons S&T program resides at ONR and addresses primarily torpedo-related issues. The Department's inventory of weapons that spend some time undersea includes mine-like torpedoes (e.g., fixed and mobile mines such as the CAPTOR mine, which is an encapsulated torpedo), the submarine-launched mobile mine, and the ASROC antisubmarine rocket-propelled torpedo launched vertically from a surface ship, as well as strike weapons such as the Tomahawk missile, launched from a submerged submarine. At the sponsor's request and with the concurrence of the Committee for Undersea Weapons Science and Technology, this assessment focused on that

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An Assessment of Undersea Weapons Science and Technology Box 1.1 Approximate 20-Year Period for Transition to New-technology Torpedo Change from MK 37 to MK 48 Antisubmarine warfare was the top Navy priority Full production capabilities Experienced personnel Design and develop operations evaluation and initial operating capability: ~9 years Solve reliability problems: ~4 years Develop fire control modifications and train people: ~7 years Change from MK 46 to MK 50 Development started in 1972 FY89 Secretary of Defense Annual Report stated, “We now anticipate cost increases and a 21-month delay in MK-50 full-scale development program.” MK 50 finally passed operation evaluation OTIIB in 1992. SOURCE: John Zittel, “Undersea Weapons S&T,” Office of the Chief of Naval Operations, N84T, Washington, D.C.,briefing to the committee, October 18, 1999. part of ONR's undersea weapons S&T program that does not include any of these other kinds of weapons but that includes primarily torpedoes and torpedo countermeasures. Nevertheless, in its discussions of the Department of the Navy's future needs and responsibilities for undersea weapons, the committee believed that a broader perspective was needed, including not only torpedoes but also mines and other weapons that spend some time undersea. The Navy's current inventory of torpedoes includes the heavyweight (submarine-launched) MK 48 and the lightweight (ship- or air-launched) MK 46 and the newer MK 50. These are based on designs and upgrades over the past 30 to 50 years. Historically, torpedoes have been developed on a 15- to 20-year cycle, as shown in Box 1.1. The MK-48 heavyweight can be used in antisubmarine warfare (ASW) and in antisurface warfare; the lightweight MK 46 and MK 50 can be used primarily for ASW. The MK-54 lightweight hybrid torpedo has a faster developmental schedule and is low cost. With the end of the Cold War, in the early 1990s, the focus of naval strategy moved to the littorals. In littoral waters, depths can vary considerably. In deeper littoral waters, the Cold War-type challenges of quiet submarines and torpedo counter-countermeasures remain. In shallow littoral waters, the ASW problem is even more complex and difficult because of the available countermeasures, the environment, and the stealthiness and small size of undersea diesel-electric submarines, all of which challenge the performance of the Navy's undersea detection and weapons systems. During this same post-Cold War period, Navy funding for torpedoes has been drastically reduced, as shown in Figure 1.1. While the overall Navy budget has dropped some 33 percent and its acquisition budget 42 percent,1 the budget for torpedoes has gone down by a factor of 7. There is currently no U.S. 1   Naval Studies Board, National Research Council. 1997. Recapitalizing the Navy: A Strategy for Managing the Infrastructure, National Academy Press, Washington, D.C., p. 11.

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An Assessment of Undersea Weapons Science and Technology FIGURE 1.1 Program funding plan and trends—total torpedo and vertical launch antisubmarine rocket (VLA) funding, FY88-FY03. This graph illustrates that undersea weapons funding has been cut disproportionately during the past decade. Acronyms are defined in Appendix D. SOURCE: John Zittel, “Undersea Weapons S&T,” Office of the Chief of Naval Operations, N84T, Washington, D.C.,briefing to the committee, October 18, 1999. torpedo production (other than the Mk-54 LRIP). Foreign countries, however, are actively producing increasingly sophisticated torpedoes. To meet these new challenges, future undersea weapons will need to have significantly improved characteristics, including reduced size to permit more weapons on platforms; reduced acquisition and life-cycle costs; longer shelf life; better deep- and shallow-water and counter-countermeasures performance; greater endurance; flexible speed control; stealth; lethality; and, for urgent-attack weapons, shorter reaction times. Technology advances toward these improved characteristics are grouped into the following areas: undersea warheads and explosives; energy conversion and propulsion; guidance and control; hydrodynamics, especially of high-speed supercavitating weapons; undersea warheads and explosives; simulation and testing; modular systems integration; and ship torpedo defense systems. A 1996 Department of the Navy master plan for undersea weapons, vehicles, and countermeasures2 provides a road map for torpedo-related technology developments and a schedule of technology insertions (see Appendix A). 2   Department of the Navy. 1996. Undersea Weapons, Vehicles, and Countermeasures: Master Plan, The Pentagon, Washington, D.C.

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An Assessment of Undersea Weapons Science and Technology MISSION OF THE OFFICE OF NAVAL RESEARCH ONR has been a widely respected sponsor of basic research (6.1) for more than 50 years and has added almost all Department of the Navy applied research and advanced development (6.2 and 6.3) to its responsibilities for the last decade. F.E. Saalfeld, Executive Director and Technical Director of ONR, described ONR's function in the following terms: ONR is in the business of investing in science and technology. And the return on that investment isn't in the first instance profit, as it would be with industry, or even knowledge, as it would be with academia. The ultimate return on our science and technology investment is warfighter capabilities. . . . As the manager of the Department of the Navy Science and Technology Program, the Office of Naval Research will continue to ensure that the portfolio includes the best available mix of investment partners and research performers. And since our ultimate shareholders are sailors and Marines, the return on investment we look for in Naval science and technology is not profits, but capabilities. 3 He described the mission of ONR as follows: ONR is the “front-end” of the acquisition pipeline. Its mission is to provide the S&T base that maintains and expands the technological superiority of naval forces. Its goal is to respond to naval requirements and lead the international S&T community, to provide both evolutionary technology improvements and revolutionary capabilities. The Navy and Marine Corps operate on—and above, and under, and from—the sea. The maritime environment extends from the sea floor to earth orbit. It is complex and challenging, and it makes Naval operations inherently difficult and dangerous even under the best conditions. The Department of the Navy has therefore historically placed great emphasis on maintaining a vigorous science and technology program in those areas where research is critically important to maintaining United States Naval superiority. A lot of those areas, uniquely important to the Navy and Marine Corps, are simply not addressed by research investments from the other Services, or for that matter from the National Science Foundation, the National Institutes of Health, other federal research establishments, or even private industry. This means that the health, strength, and growth of our scientific and technical capabilities in those fields depend upon the Department of the Navy. On behalf of the Department of the Navy, the Office of Naval Research must ensure continuing United States leadership in these vitally important scientific and technical disciplines. It does so through research, recruitment, and education, all done with a view to sustaining an adequate base of talent and the critical infrastructure necessary to carry out research and experimentation.4 It is with these expectations in mind that the committee undertook the review called for in the terms of reference (see Preface). 3   Saalfeld, Fred. E., Office of Naval Research. Speech given at the Naval Science Assistance Program (NSAP) All-Theater Conference, held at the Naval Research Laboratory, Washington, D.C., June 23, 1999. 4   Saalfeld, Fred E. 2000. ONR Presents . . . National Naval Responsibilities in Science and Technology, Office of Naval Research, Arlington, Va., February 27.

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An Assessment of Undersea Weapons Science and Technology STRATEGY OF THE OFFICE OF NAVAL RESEARCH The committee was given information on ONR's current strategy for S&T. The strategy includes a continuation of fundamental research (6.1), applied research (6.2), and advanced technology development (6.3). To facilitate the transition to efforts in higher budget categories, about half of the 6.2 and most of the 6.3 effort will be concentrated in areas corresponding to budgetary spikes supporting Future Naval Capabilities (FNCs).5 The FNCs are chosen by a top-level Navy and Marine Corps board, and the corresponding S&T is defined in detail by integrated product teams. The spikes are to have approximately 3- to 5-year lifetimes and include scheduled milestones. The current ONR undersea weapons S&T program includes elements that support several of the FNCs, notably littoral antisubmarine warfare and platform protection.6The ONR strategy also identifies S&T programs (mainly 6.1 and 6.2) that address National Naval Needs, which constitute a national naval responsibility. It is understood that National Naval Needs should have continuity and a stable budget. The processes for executing this strategy are under way. While the undersea weapons S&T program has not yet been identified as a National Naval Need, a major motive for the present study is to examine whether it should be so identified. REPORT OUTLINE Chapter 2 of this report contains the committee's assessment of the existing ONR undersea weapons S&T program, following the aforementioned torpedo-related categories into which the program's budget is divided. The chapter also reviews the program from the point of view of the issues listed in the terms of reference and attempts to answer the two questions posed there. Chapter 3 contains the committee's views on the future of the Navy's undersea weapons in a broad context not limited to torpedoes. Findings, conclusions, and recommendations are presented in Chapter 4. 5   RADM Paul G. Gaffney II, USN, Director, Test and Evaluation and Technology Requirements. Future Naval Capabilities Fiscal Guidance – Information Memorandum, Office of the Chief of Naval Operations (N91), The Pentagon, Washington, D.C., November 23, 1999. 6   Outside the S&T program, platform-related acquisition programs, e.g., submarines and DD-21, can also affect the Navy undersea warfare funding structure.