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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Chapter 2
Mine Warfare

The post-Cold War environment and the disappearance of the Soviet naval threat have reduced the Navy's focus on the blue waters of the open ocean and instead concentrated its attention on the littorals of the world. During the Cold War, the Navy was sized and configured to engage the Soviet fleet and its land-based naval air. Focused attention on the Soviet blue water threat resulted in comparative neglect of the unique requirements of operations in close proximity to land. As an aside, it is ironic that the Navy-Marine Corps team actually fought all its wars during that period—Korea, Vietnam, Grenada, Persian Gulf—in the littoral regions.

Today and for the foreseeable future, the nation will require a Navy different from the one that was developed to counter the Soviet threat. The phrase, ''we will never again be faced with an opposed amphibious assault," first articulated in the 1960s, is heard no more. The panel foresees an increasing number of instances where the Navy and Marine Corps will be required to operate freely in near-shore waters, and the forces at their disposal, including MCM forces, should be configured such that they are able to operate effectively in these environments.

At the same time, during the projection period of this study (2000-2035), a blue water threat may again emerge. Thus, the Navy of the future will require a balanced capability that can sustain operations in both the blue water and the littoral environments.

The experiences of Wonsan in the Korean conflict and Kuwait in the Persian Gulf War indicate that sea mines, in the hands of a far lesser power that knows little of how to use them, can defeat, at least temporarily, the most powerful navy in the world. Today at least 45 countries, in addition to the United States and the

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

former Soviet states, possess mining capability, and any nation can acquire such a capability in a matter of months. At least 21 countries are known to produce mines, and 13 are confirmed mine exporters. The People's Republic of China, for instance, has sold copies of Russia's AMD/KMD II bottom influence mines in both the 500- and 1,000-kg versions and has marketed its own rocket-propelled mine, the EM52, designed to be deployed in relatively deep water against both submarines and surface ships. Yugoslavia produces mines based on Russian designs. Italy produces the Manta and computer-controlled MP-80 influence mines. It was a Manta mine laid in about 60 feet of water that seriously damaged the hull of the USS Princeton (CG-59) during the Persian Gulf War and disabled its Aegis antiair combat system and vertical launch system (VLS) missile batteries. Chile offers three mines for sale, including a microprocessor-controlled magnetic influence mine, the MS-L, and a version targeted at landing craft, the MS-C. Unfortunately, the known 45 producers of mines do not, in themselves, define the threat since virtually any country can produce an effective mine. It was the LUGM-145 moored contact mine produced by Iraq that damaged the USS Tripoli (LPH-10) during the Persian Gulf War. Further, mines do not have to be of modern design to pose an effective threat to naval operations. The mines used by Iran during Operation Ernest Will were from the Russo-Japanese War (1904-1905) with two upgrades. Many of the Turkish mines in the Dardanelles that forever changed world history during the Gallipoli campaign of World War I were Russian mines that floated through the Bosporus and were salvaged, refurbished, and replanted.

Although mines can be cheap and simple, countering mines will most probably become more difficult due to increasingly sophisticated fusing methods and the ease with which mine signatures can be reduced. Miniature solid-state firing mechanisms and logic processors will allow increasingly complex acoustic-, magnetic-, and pressure-triggered mines that will evade existing sweeping techniques. Mines with reduced acoustic signatures will seriously degrade the performance of mine hunting sonars. The plastic-hulled Manta and the wedge-shaped Swedish Rockan GMI-100 are current examples of reduced signature mines that are believed to be difficult to detect. It is not unreasonable to expect to encounter mine systems that use distributed sensors and remote command and control (RECO) activation or deactivation through acoustic or electromagnetic links.

During the past 45 years, in spite of the very modest effort devoted to mine design the explosive charge carried by the typical mine has essentially doubled in energy output; its instrument section has been reduced from 20 percent of its volume to a space the size of a soda can through the adoption of modern electronics; its lethality range has increased from a few tens of feet athwart ship to a half mile through the use of mobile warheads; its logic systems have been made more resistant to countermeasures; and through the use of stealth technology, its ability to evade mine hunting sonars has increased. Future naval forces will be confronted with more capable mines made possible by evolving technology.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

Prominent among the mine designs likely to be encountered between now and the year 2035 are (1) the self-burying mine, which would so degrade the performance of current mine hunting sonars as to force increased dependence on slower mine sweeping techniques; (2) another doubling of the warhead's energy output and continued reduction of the instrument section, thus increasing the delivery capacity of all mine laying platforms; (3) the introduction of alternating magnetic (AM), underwater electric potential (UEP), and possibly, pure pressure mine sensors; (4) the introduction of distributed sensor minefields in which the long-range multiple-shot kill component is located at a single point within or about the field; (5) mines specifically targeted against mine countermeasures (MCM) platforms, including helicopters; (6) the use of powerful minicomputers to increase the mine's target discrimination and resistance to countermeasures; and (7) whole minefields capable of remote command-on and command-off control and of changing sensitivity settings, sensor combinations, countermeasures logic, and even location on remote command. None of the possible advances enumerated above are particularly new, and all are within the reach of current technology. New technology developments will enable the design and fabrication of even more capable mines.

The Panel on Undersea Warfare chose to utilize the classified Naval Studies Board report Mine Countermeasures Technology1 as starting point for its examination of mine warfare technology. The panel also took account of the 1995 White Paper issued by the Chief of Naval Operations2 calling for a major sea change in the Navy's approach to MCM operations. Specifically, Admiral Boorda directed that the Navy's MCM force be transformed from a dedicated on-call force to an organic force capable of traveling at battle group speeds, and that MCM be mainstreamed into the fleet as a professional competency at all ranks and rates.

The panel's deliberations were guided by a view of MCM capability that enables effective pursuit of the following three objectives: (1) reduce the mine threat to its absolute minimum at each phase of an operation; (2) obtain maximum leverage of all available MCM assets; and (3) reduce the size and weight of all MCM systems without sacrificing capability. The panel believes that these objectives can be achieved and that a balanced MCM force, organic to the fleet and capable of removing the mine threat in keeping with an assault timetable or power projection schedule, can be achieved at relatively modest cost by the year 2005. Further, the panel has identified technologies whose far-term development would provide the Navy and Marine Corps team with an effective MCM capability well into the mid-21st century.

1  

Naval Studies Board. 1992-1993. Mine Countermeasures Technology, Vol. I-IV, National Academy Press, Washington, D.C.

2  

Boorda, J.M., ADM, USN. 1995. "Mine Countermeasures-An Integral Part of Our Strategy and Our Forces," White Paper, Office of the Chief of Naval Operations, Washington, D.C., December.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

The mine threat is expected to grow in technical sophistication over the projection period of this study; there is a substantial likelihood that mines will be developed that are difficult to detect and/or sweep. To deal with this issue, and more immediately with the threat of high-density minefields in the surf zone and on the beach, the panel addressed a number of so-called brute force technologies that deal with groups of mines, rather than single mines and obstacles, and do not depend on specific mine characteristics such as acoustic or magnetic signature, the type of fuse employed, or details of how the mine is deployed.

The panel restricted its consideration mainly to sea mines and to mines and obstacles found in the surf zone and the craft landing zone.

MINE COUNTERMEASURES: A VITAL CAPABILITY FOR FUTURE NAVAL MISSIONS

The Navy of the future will be expected to maintain sea control; to transit and operate worldwide at will; to navigate restricted waters, open channels, and sea lanes; and to project power ashore. It will be expected to land forces, supplies, and equipment rapidly and safely to support national objectives. Unless properly countered, mines will restrict, if not prevent, the Navy from carrying out these missions.

Technology in mine and countermine warfare in the next 30 years will be different than in the past because of (1) replacement of the Cold War preoccupation with port breakout, with the need for power projection into newer, troubled areas, which entails the protection of far-flung battle groups against mines, the clearance of shipping lanes, and in extreme cases, amphibious assault; (2) present and future reductions in defense budgets, which require that goals be pursued in the most cost-effective manner; and (3) the need to carefully integrate political and humanitarian with military imperatives, such as weapon choice, in the context of global peace.

Changes are required to meet the new missions and rules of engagement. Battle groups can no longer rely on a dedicated MCM force to provide protection against mines everywhere and anywhere. Each battle group must assume responsibility for self-protection against the mine threat with new organic MCM capabilities. The present, dedicated, MCM force must be reconfigured for worldwide operations. Mines are cost-effective weapons that can serve as an important force multiplier, but humanitarian and political considerations mandate that they not be deployed without sufficient control to ensure the limitation of collateral damage and injuries to third parties.

A VISION OF FUTURE MCM FORCES

It is anticipated that future battle groups will have organic MCM capability in the form of air, surface, and underwater platforms. The air platforms will likely be helicopters with improved, lighter MCM sonars, LIDAR devices, and

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

possibly supercavitating projectile mine killers. The surface platforms will likely include remotely controlled, unmanned, small, stable, long-endurance platforms, possibly based on small waterplane twin hull (SWATH) technology, towing sonars and other MCM devices. Underwater platforms will include swim-ahead UUVs with mine detection, classification, and neutralization capability. The MCM force of the future will likely be composed of smaller and more numerous vessels, transported by a mother ship, that can be rapidly deployed worldwide to keep shipping lanes open and harbors cleared. Such a force will be designed to counter an arsenal of new mines with remote control, networking, and selective targeting capability.

It is unlikely that a single technology or system will emerge that alone will render the mine threat harmless. It is expected that future mine countermeasures will continue to consist of a number of systems ranging from the elemental to the highly sophisticated, each essential to a balanced capability to deal with the overall mine threat.

Five main thrust areas must be pursued in order to meet the MCM challenge of the future:

  1. Robust intelligence, surveillance, and reconnaissance capability.

  2. Integration of MCM as a capability organic to the battle force. This includes specific MCM capability resident on selected battle group combatants and expanded MCM capabilities provided by MCM ships and helicopters that are transported with the battle group or the amphibious ready group (ARG).

  3. Technologies that address primarily the very hostile mine detection and neutralization environment of the surf zone and the craft landing zone. These generally fall into the brute force category.

  4. Advanced networked sensor and weapon systems consisting of controllable mines and including autonomous and semi-autonomous detection devices.

    Application of cost-effective mine shock hardening and acoustic and magnetic signature reduction technologies in all new construction ships.

The following paragraphs expand on these thrusts.

Intelligence, Surveillance, and Reconnaissance

Accurate and complete intelligence, surveillance, and reconnaissance is the most effective means of enhancing the capability of MCM forces. ISR enhances the efficiency of MCM operations by reducing the threat to a minimum prior to the initiation of sweeping, hunting, and neutralization activities. ISR was the highest-priority recommendation of the Naval Studies Board report Mine Countermeasures Technology.3 The importance and priority of that recommendation are reinforced and restated by the present study.

3  

Naval Studies Board. 1992-1993. Mine Countermeasures Technology, Vol. I-IV, National Academy Press, Washington, D.C.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

The recent increased attention to surveillance through such programs as the Radiant Clear Program, which seeks to develop a capability for littoral remote sensing, and the emphasis on reconnaissance-related research and development signal a possible turning point that, if pursued further, could provide the quality of intelligence that will become an effective force multiplier. It is to be emphasized that for this gain to be realized, priorities on the use of surveillance assets must be set now and the infrastructure installed for collection, analysis, and timely display of the resulting information. Intelligence requirements include a comprehensive database of world mines describing capabilities and characteristics, detection and triggering technologies, size and locations of stockpiles, manufacturing facilities, transportation routes, mine laying facilities and capabilities, and likely areas of deployment. Further, foreign manufacture and sale should be monitored, much like what is now done with respect to submarines. A robust ISR effort should include the acquisition and examination of foreign mines. This is a relatively inexpensive effort that holds promise for significant payoff, but one that has been poorly pursued in the past.

An effective factory-to-seabed ISR system should include a full set of ISR methods, including surveillance by satellite, atmospheric manned and unmanned vehicles, submarines, human intelligence, and special forces. Such a system would enable the preparation of detailed a priori plans and provide real-time support for the movement of forces. Ultimately, it could provide the option of interdicting mines prior to planting, or avoiding mined areas entirely, or failing both, it will allow MCM forces to be concentrated on mined areas of known characteristics.

Battle Group and Task Force Organic MCM

In a future where conflicts are likely to arise suddenly and unexpectedly, it will be necessary for naval forces to be capable of reacting swiftly and independently. Since the geographical locales of possible conflict are so widely dispersed, it will be impractical to create forward-based MCM forces. Thus, the dedicated MCM force the Navy has now must be transformed into a set of MCM assets carried by, or organic to, battle groups and task forces. The latter will be required to provide self-protection and deliver MCM capabilities to theater along with Navy presence.

A battle group MCM force might consist of a specially configured support ship with MCM command and control capability (C4I), and the ability to transport and maintain small MCM ships and helicopters. MCM C4I capability should include links to other task force elements, access to environmental sensors, including those deployed on satellites, as well as other data sources and decision aids to support tactical MCM. Provision should be made for special signals such as those required to implement remote mine neutralization on command. New hull concepts permit the design of smaller vessels capable of operating effec-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

TABLE 2.1 Notional Small MCM Vessel and Support Ship

Small MCM Ship Design

Possible Sensors

Support Ship Characteristics

Length: 36 feet

Displacement: 26 tons

Payload: 4 tons

Low signature

24 knots

Gas turbine/electric drive

Active EM cancellation

SWATH hull design

Sea state 4 capable

Modular (to allow air transport)

Unmanned 100 n. mi. endurance

Forward looking, low-grazing-angle LIDAR and sonar

Expendable mine neutralization

GPS navigation

Remote optical system

VDS sonar

Acoustic pulse power

Laser line scanner

C2-RF/fiber

Optic, mammal, bioacoustic adjunct

Deployable UUV

Size: up to LSD dimensions

Payload up to

2-10 MCM ships

2-10 MCM helicopters

JMCIS compatible

Battle group speed: 28 knots

Number: as appropriate for size and operational concept

 

tively in sea state 4 conditions, and advances in lightweight sonars, synthetic aperture techniques, and lighter sweep gear will enable these smaller vessels to provide the functional capability of today's larger ships. Table 2.1 outlines a possible design.

Technology currently under development or likely to become available in the near future will allow battle groups to carry light helicopters that are capable of night operations and able to carry modular payloads including advanced electro-optic mine hunting systems, lightweight acoustic and mechanical sweeps, and mine neutralizers launched directly from the helicopter, such as gun-fired high-speed supercavitating projectiles. These will be augmented by off-board, remotely controlled, autonomous or semi-autonomous vehicles, with acoustic and other sensors and systems for mine detection, classification, and neutralization and with the endurance and ability to search ahead of the battle group at moderate transit speeds up to 15 knots. Undersea variants will provide covert reconnaissance capabilities.

Brute Force Mine and Obstacle Clearance

There will be situations in which MCM operations that deal with one mine at a time cannot be conducted because of the density of the threat and lack of time or because normal MCM operations are slowed or ineffective due to the harshness of the environment, stealthiness of mines, or presence of buried mines. In these cases brute force methods of breaching will be required. This is likely to be especially true in the surf zone (SZ), the craft landing zone (CLZ), and the beach regions-where a dramatic increase in the density of mines and obstacles may be expected. Brute force breaching methods may require complex engineering,

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

precise timing and fusing of explosives, unique chemical systems, accurate navigation, and high reliability. There are two promising approaches that warrant further development: (1) precise time-space control of explosives that will remove mines and obstacles, and (2) the placement of a foam causeway over a mine field.

The Naval Studies Board Mine Countermeasures Technology4 study recommended a concept in which precisely positioned (to GPS-level accuracy), impact-buried bomb explosives timed to go off nearly simultaneously, forming an equivalent buried line charge, are used to excavate a channel through the SZ, the CLZ, and through the minefield up the beach. See Appendix F for an explanation of the efficacy of simultaneous detonation for explosive channel excavation. Mines and obstacles are effectively removed from the deepened channel, which eventually fills with water, by the excavation process. The phenomenology, scaled dimensions, and removal of mines and obstacles have been confirmed by a scaled experiment conducted jointly at the UK Weston Supermare Shallow Water Test Range by the Naval Surface Warfare Center (NSWC) at White Oak, Maryland (now NSWC at Indian Head, Maryland).5

Independently, the Lawrence Livermore National Laboratory's (LLNL's) Defense Studies Group has proposed similar concepts using bombs available from inventory, with special fusing. Results of the NSWC experiment are in agreement with calculations performed by NSWC and LLNL.

If, as discussed in Volume 5: Weapons of this series, advanced explosives could be successfully developed in the 2000-2035 time frame, with several times current explosive fill effectiveness, a wider range of options for delivery and use of controlled space-time explosive patterns might become possible. The panel recommends that investigations and appropriately scaled experiments continue on channel excavation phenomenology and explosive placement sensitivity. Some of the needed data can probably be obtained using high-g centrifuges. An overall modeling capability should be achievable to enable tradeoffs of explosive weight, spacing, penetration depth, and channel width for different delivery and fusing options, threats, and environmental conditions.

Research conducted at Sandia National Laboratories on petrochemical-based binary materials has led to the development of quick-setting rigid polyurethane foam (RPF). The chemicals, transportable as liquids, when mixed and exposed to air form a relatively tough, quick-setting rigid structure that floats on the surface. The volume expansion between the component liquids and the final rigid foam is

4  

Naval Studies Board. 1992-1993. Mine Countermeasures Technology, Vol. I-IV, National Academy Press, Washington, D.C.

5  

Furr, W., R. McKeown, and L. Taylor. 1996. "Mine and Obstacle Breaching by Explosive Evacuation in the Surf and Beach Zones," Technology and the Mine Problem Symposium, Monterey, Calif., November 18-21.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

a factor of 20 to 60, and the resulting structure has a bearing strength sufficient to withstand the repeated passage of heavy vehicles, including tanks. Tests indicate that the foam can absorb some degree of explosive blast energy, can withstand puncture by bullets without significant structural weakening, and poses no extraordinary fire hazard. Tests also indicate that foam will incapacitate the sensors on pressure and tilt-wand mines if they are immobilized in the foam, will provide a standoff for magnetic mines, and will reduce the profile presented by obstacles to assault traffic. As important as these results are, more experimentation under actual operational conditions is needed to fully evaluate the potential of foam.

Other brute force systems offer promise and may be worthy of further development. Some concepts such as guinea pig ships and barges have been used operationally in the past, for example, in Haiphong harbor, during the Vietnam conflict. In this case, the ship was not employed as a sweep platform, although it was designed as one, but rather was used to prove that the United States had indeed cleared the harbor of mines. The same concept with improved automation, remotely controlled unmanned platforms, and precise navigation remains an attractive a means to prove that a safe passage has been cleared through a minefield.

Autonomous Networked Undersea Systems

Advances in sensors, signal processing, and computational power will enable the development of autonomous and semi-autonomous systems. In support of ISR, networked multiple undersea surveillance systems using small, autonomous undersea vehicles have significant potential for providing a covert mine surveillance, detection, and neutralization capability. These systems could be smart systems, with a hierarchy of intelligence and capability, intervehicle communications within the water column, and communications to remote command and control nodes. They could operate autonomously, reporting only when interrogated or as programmed. The development of communications technology, acoustic and otherwise, will be an essential enabler for this type of system. Data transfer rates beyond those now possible will be required. Accurate navigation also will be required. Additionally, autonomous vehicle systems could be combined with other distributed sensor systems deployed either simultaneously or in sequence.

Vehicle technology pursued in past UUV research programs forms the basis for future efforts. Multiple vehicle approaches, which offer the efficiency of systems operating in parallel, could include stealthy surface vehicles and bottom crawling devices. Specific requirements, concepts of integrated operations, and possible countermeasures must be investigated, however, to more clearly define the viability of any single design. Such a system can be a force multiplier capable of detecting, classifying, and neutralizing mines either as a stand-alone system or incorporated as an integral part of a larger networked system. On the offensive

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

side, the same technology can enable the development of networked autonomous weapons, including mines and minefields, with fail-safe remote control and command links and selective targeting. Such an offensive system can be a force multiplier by denying large areas of the ocean to enemy vessels without posing any danger to friendly forces and noncombatants and without tying up valuable Navy ships or putting personnel in harm's way.

Magnetic and Acoustic Signature Reduction and Platform Shock Hardening

Mine fuses rely on sensing the magnetic and acoustic signatures of ships and submarines for detection, classification, and initiation of their attack mechanism. Expected technology advances in mine fuses will yield improved sensitivity and noise rejection. Unless a commensurate effort is made to reduce the signatures of current and future platforms, their vulnerability to mines will increase in the future. Signature reduction measures that utilize both passive and active signature reduction techniques can be developed and implemented. Enabling technologies include sound- and vibration-absorbing materials and isolation techniques, active vibration and acoustic signature control, closed-loop adaptive magnetic degaussing systems, and cathodic current reduction.

Even with the most aggressive campaign to reduce signatures, there remains the possibility of triggering a mine. Indeed, a simple contact mine is not impaired by target signature reduction. Given this situation, especially as organic concepts of MCM are implemented wherein more ships will be placed in the vicinity of mines and minefields, it is essential that these platforms be shock resistant.

EMERGING ENABLING TECHNOLOGIES

Although the priority areas cited above will form a foundation for a robust future MCM capability, they must be bolstered by continued support for research in promising emerging technologies. The capability that the Navy is able to field in the future depends on research undertaken today. None of the required systems or technologies will be developed without a strong underlying R&D program. Lighter-weight sweeps with wider-swath, higher-resolution sonars; synthetic aperture sonars; active (laser) and passive optical systems; expendable neutralization methods; sonars based on biosonars (mammals) capable of detecting buried mines; and pulsed-power devices and biosensors will not be realized without a commitment to R&D. UUVs with intelligent control, long range, and endurance; networked underwater sensors; rigid foam causeways; small and stable surface platforms; and high-data-rate acoustic communications will not emerge without concomitant research. Optimum employment of systems and sensors based on the characteristics of the highly variable littoral environment will not occur without ocean physics, sedimentology, and meteorological research. The

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

full benefits of modeling and simulation in the design of sensors and systems and in developing the most effective operational employment of the full spectrum of MCM capabilities will not be realized without an underlying research base.

TOWARD A BALANCED MCM FORCE: THE NEAR TERM

On the path to the MCM capabilities of 2035, the panel believes that the near-term concepts, technologies, and systems should, when integrated with existing capability, provide the Navy-Marine Corps team with the ability to clear mines in stride by the year 2005 or earlier, at reasonable cost. The panel kept several objectives in mind when evaluating these concepts and technologies. The first objective is to pare the mine threat in a given campaign to the minimum that must be dealt with effectively as a function of three phases of the campaign—the most critical phase in which the first forces are inserted, the second phase when the heavy manpower and logistics must be landed, and the third phase when maximum sea-based traffic is expected. From the MCM standpoint, the major distinction between the phases involves the channel widths to be cleared and the time to do so. The second objective is to achieve a balanced and flexible MCM system capable of countering the full spectrum of mine threats. The third and final objective is to select concepts that will add clearance speed and efficiency to the MCM system at minimal costs and that can be implemented in the near-term future.

Intelligence, Surveillance, and Reconnaissance

Intelligence, surveillance, and reconnaissance, considered as a whole, was the highest-priority recommendation of the Naval Studies Board Mine Countermeasures Technology report.6 A continuous, robust ISR effort targeted at potential mine threats can greatly enhance the efficiency of MCM operations by enabling accurate characterization of the threat prior to initiation of sweeping, hunting, and neutralization activities. Many of the assets necessary for the intelligence and surveillance functions already are in place, and much of the technology development necessary for the reconnaissance function has been, and will continue to be, supported by entities other than the Navy.

Intelligence can provide information on the type, size, and location of an adversary's mine stockpile, the method and route of transportation to mine layers, platforms allocated to mine laying duty, and the adversary's plans for mine defenses. Surveillance by satellite, manned and unmanned aerial vehicles, submarines, human intelligence, and special forces can track mine laying activity from bunker to beach or sea bottom. Reconnaissance, preferably covert, by

6  

Naval Studies Board. 1992-1993. Mine Countermeasures Technology, Vol. I-IV, National Academy Press, Washington, D.C.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

airborne, surface, and subsurface sensors including mammals can provide ground truth to corroborate intelligence and surveillance information. Integrating ISR into MCM operations may allow the interdiction of mines prior to planting (rules of engagement permitting) or the avoidance of a mined area entirely; failing both, it should allow MCM forces to be concentrated solely on mined areas of reasonably well-known characteristics.

A number of surveillance assets, including electronic intelligence, satellite-based photo-optic cameras and sensors, manned and unmanned surveillance aircraft, Joint Surveillance and Target Attack Radar System (JSTARS),7 submarines, special forces, and human intelligence can be used. The greater need is to set firm priorities for the tasking of these assets and to develop the architecture and infrastructure necessary for the mine warfare commander to receive the assembled data properly formatted and in a timely fashion.

The panel notes that the use of submarine mine layers represents a possible weak link in surveillance provided by the sensors and platforms noted above. Because of the proliferation and increased capabilities of submarines worldwide, with the capability of laying mines included, the panel believes that this weak link should be strengthened. The Office of Naval Research (ONR) and the Naval Research and Development Division (NRaD) at the Naval Command, Control, and Ocean Surveillance Center (NCCOSC) are supporting the development of remote sensors capable of detecting mine laying activity in waters seaward of the surf zone (ONR program) and both on land and in water (NRaD program). NRaD's Joint Littoral Awareness Network (JLAN) uses a combination of magnetic, acoustic, seismic, and chemical sensors to detect military activity on land and acoustic, electrical field, and magnetic sensors seaward of the high water mark. Sensor reporting is through a low probability of intercept (LPI) radiofrequency (RF) link (acoustic for the sea version) to area reconnaissance platforms (submarine, aircraft, UUV, or satellite). ONR's Deployable Sensor Project (DSP) uses passive acoustic, seismic, and magnetic sensors to detect surface and subsurface traffic patterns and the sound of mines or mine anchors impacting the bottom. Data are acoustically communicated to a monitor for satellite uplink. Utilizing JLAN for land mine surveillance and DSP in all shallow-water mining depths, including the deeper waters of straits and choke points, seems a reasonable utilization of both systems. Additionally, it should be pointed out that the broader capability of JLAN would provide useful continuing surveillance information for highly maneuverable Marine units ashore, and the DSP system could be used also for ASW surveillance.

7  

The JSTARS radar is capable of distinguishing tracked vehicles from rolling stock, identifying helicopters and slow-moving aircraft, and pinpointing rotating antennas and jammer locations, as demonstrated in recent tests. It can also track surface ships and craft over the same wide area. While the JSTARS radar will begin to track ocean waves when the wave height exceeds sea state 3, the manufacturer has developed a filter to negate this effect and can install it on request.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

The information gained through intelligence and surveillance will never be perfect, and ground truth in the form of reconnaissance in the period immediately preceding commitment of MCM forces will be required. Encouraging progress in covert, semi-covert, and overt minefield reconnaissance systems has been made over the past few years. Particularly noteworthy reconnaissance systems are discussed below.

Mine Reconnaissance

Near-term Minefield Reconnaissance System

The Near-term Minefield Reconnaissance System (NMRS), under development by the submarine community, is a minefield reconnaissance UUV that can be launched and recovered through the submarine's torpedo tube. The torpedo body is fiber-optically controlled, with data recovery in real time. The system is equipped with ahead-looking and side-scan sonar for moored and bottom mine detection and with either TV or LIDAR for mine inspection. In addition to the submarine's mine surveillance role, NMRS gives it a covert reconnaissance capability as well.

Since the submarine is likely to be the first naval platform to reach an intended assault area, it will, of necessity, have to transit more distant areas, including straits, in which mines may have been planted in anticipation of a naval presence. NMRS will stand it in good stead in its own defense as well as proofing such areas for following submarines and surface ships. Further, the deep scattering layer, which rises near the surface at night, has been demonstrated to adversely affect both hull-mounted and variable-depth sonars using mine hunting frequencies. The submarine, with its depth capability, may be less affected by these scatterers than will those reconnaissance systems tied to the surface, such as the Remote Minehunting System (RMS).

Rather than develop in parallel a covert UUV mine reconnaissance system organic to itself, the MCM community should evaluate a low-cost NMRS for use by surface ships and craft. NMRS could be utilized with ease from the MCM-1, the MHC-51, an amphibious ship, or even the small SWATH craft discussed below.

Dolphin Reconnaissance Vehicle

Originally slated for the Advanced Concepts Technology Demonstration (ACTD) Phase I, the Dolphin semi-submersible (also known as the Remote Minehunting System [RMS]), equipped with an ahead-looking sonar and a towed sidescan sonar deployed from a keel mount, has already been tested as a semi-covert minefield reconnaissance system and is now mounted on the USS Cushing (DDG- 963). Since Dolphin uses a snorkel to support a diesel engine for propulsion, it

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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has the advantage of being controlled by a radio link and using GPS for more precise navigation. Further, data from its sensors can be transmitted in real time. Because of the snorkel and diesel engine the system is not perfectly covert, it may have occasional trouble with surface debris, and care must be taken not to snag its towed sonar in shallow waters and in kelp beds.

Airborne Electro-optical Reconnaissance System

Although it is not covert and therefore could be vulnerable to hostile action, helicopter-borne electro-optical technology, such as that used in the Magic Lantern and Magic Lantern Adaptation R&D programs, has an important role to play in minefield reconnaissance, mine surveillance, and mine neutralization. It is unique in its capability for rapid, wide-area assessment from safe standoff (in unopposed waters). With further development it is expected that a two-dimensional search laser will detect proud mines and obstacles on the beach and in inland minefields and that a three-dimensional gated system will detect floating mines, moored antishipping mines, and bottom mines where optical and clutter conditions allow penetration. Whether these two capabilities should be merged into a single system is a decision to be made on the basis of technical feasibility and cost.

Clandestine Mine Reconnaissance and Countermeasures System

None of the three minefield reconnaissance systems discussed above are very effective at detecting buried mines; yet the shallower end of the littoral regime is where mines are most likely to become buried by natural forces (wave scour, traveling sand ridges, and mud bottoms). Also, in the future naval forces must be prepared to face deliberately designed self-burying mines, a relatively trivial adaptation. A field composed of buried mines would seriously degrade current mine hunting sonars and force an increased emphasis on slower and more laborious mine sweeping. A clandestine mine reconnaissance and countermeasures system (CMR/CS) is proposed by the panel as a possible reconnaissance solution to that problem.

CMR/CS is intended primarily for reconnaissance in depths between the surf zone and 40 feet of water, but it can cover waters of considerably greater depth. Envisioned is a small SWATH (for better seakeeping) platform with an overall length of about 36 feet, a beam of 15 feet, draft of 6.5 feet, and displacement of about 28 tons. The platform should have a range of about 100 nautical miles, with a payload of around 3 tons, and a maximum speed of 25 knots, with a cruising speed of 15 knots. The platform should be designed to be manned (three-person crew) or unmanned and remotely controlled. For the latter, the platform would be controlled by a fiber-optic link with an encrypted LPI RF link for backup. A more detailed description of this small MCM ship and its capabili-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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ties and uses is given below in this chapter. Mine detection, classification, and either marking or placement of delayed neutralization charges could be done by two Mk-7 mammal systems aboard each platform trained in the detection of moored, bottom, and buried mines. An expendable mine neutralization system could also be deployed from the CMR/CS. The effectiveness of bottom charges for neutralization of buried mines must be determined. Experience over the past 40 years supports the belief that mammals can be trained to operate effectively with an unmanned system, but the provision of a three-man (operator plus two trainer or handlers) crew has certain advantages.

CMR/CS could be transported by a combatant or amphibious ship (or by air if necessary) and launched from over the horizon for a high-speed (15 to 25 knots) run into the search area. Search speed for the system would be 3 knots, covering a search path 50 yards wide. With a 2-hour on-station time, each unit could cover around 600,000 square yards. The system would be capable of operating day or night, but night operations are envisioned for greater covertness. Further covertness could be achieved by utilizing stealth technology in the construction. The search speed noted above is based on detection and classification only. If the mammals are to place a transponder or a command-detonated neutralization charge on each mine contact, the speed of advance would be reduced.

The CMR/CS concept provides for reconnaissance against moored, bottom, and buried mines unmatched by any other search system. For that reason the panel believes that the Navy's support of biosensor research should be continued with the ultimate aim of replacing the mammals with a mechanical system of equal capability aboard the SWATH vehicle. Beginning with the research conducted by the Naval Undersea Center, slow but steady progress has been made in understanding the mammal's method of echo location. For instance, in the early 1970s, thin plates of different metals and different geometric shapes were used to compare the discrimination capability of porpoises and divers. The diver was provided with a helmet containing a sending and two receiving transducers. Test results indicated that the instrumented divers performed as well as, and in some cases better than, the porpoise. Subsequent research, including that with neural nets, indicates that developing a mechanical equivalent of the porpoise may be feasible. This technology requires further research before it can be considered for development.

Complementary Systems

The panel sees significant value in an airborne laser that is capable of rapidly conducting reconnaissance seaward of the surf zone against floating mines and moored mines (bottom mines if possible) and is accompanied by a neutralization system, an example of which might be the 20-mm system built around the rapid airborne mine clearance systems (RAMICS) concept using supercavitation projectiles. This capability is essential to clear floating mines ahead of the surface

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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MCM forces. The presence or absence of mines and obstacles in the SZ and CLZ can be detected adequately by satellites—even the Systeme Probatoire d'Observation de la Terre (SPOT) satellite, with 25-m resolution, detected the fortification of the Kuwaiti beaches by manned and unmanned aircraft—and by the coastal battlefield reconnaissance and analysis (COBRA) UAV with its multispectral video sensors and battlefield surveillance, forward-looking video if development of that system is completed. Similarly, the Army's Airborne Standoff Minefield Detection System (ASTAMID) UAV using IR sensors could also be employed for this purpose.

In perfecting a helicopter-borne electro-optical system for both reconnaissance and clearance seaward of the surf zone, a laser-stripe-type imaging system should be considered for possible advantages over synchronous line scanners and gated camera systems. The streak tube imaging LIDAR (STIL) is a three-dimensional imaging system that uses a pulsed laser transmitter and a streak tube charged-coupled device (CCD) receiver to time resolve the backscattered light from an ocean volume illuminated in azimuth by a fan beam of laser light formed using a fixed cylindrical lens. By orienting the fan beam perpendicular to the vehicle motion, the in-track dimension is sampled by matching the pulse repetition frequency of the laser to the forward speed of the vehicle, thus sweeping out a three-dimensional ocean volume in a push-broom fashion without the aid of a scanner. In this manner, a high-resolution three-dimensional image of the entire illuminated water volume and bottom (if shallow enough) is obtained. Since the return is recorded at all ranges, a laser-stripe-type system inherently has an extremely large depth of field, providing target detection or classification from the near field out to photon counting limits or the bottom.

The panel believes that these minefield reconnaissance systems—NMRS (submarine and organic), airborne LIDAR, RMS, and CMR/CS—will provide the Navy with the balanced, dedicated organic reconnaissance capability it needs. Combined with intelligence and surveillance, they will provide the ground truth required to achieve unprecedented efficiency in the operation of its MCM assets.

Task Force Organic MCM

Today's MCM mission execution relies largely on a dedicated MCM force, which includes the mine command and control ship, the USS Inchon (MCS-12), the Avenger (MCM-1) class mine hunting and mine sweeping ships, the Osprey (MHC-51) class coastal mine hunters, and the air MCM MH-53 helicopters. Significant efforts are being made to update the current force and make it more effective by forward-basing some MCM assets and introducing new technologies as they become available. Nonetheless, current MCM assets are not integral to naval combat forces. It takes significant time to move them—as much as 51 days to heavy-lift the MCM and MHC ships—to an area of operations. In order to provide the fleet with a robust organic capability to move to an objective quickly

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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and safely, battle group combatants should be provided with the following organic capabilities:

  • Remote mine hunting. Envisioned is a remotely controlled vehicle such as the RMS now being developed by the Navy for fleet deployment or, as technical advances permit, a semi-autonomous underwater vehicle with acoustic and other sensors and systems for mine detection, classification, and neutralization, with the endurance and capability to search ahead of the ship from which it was deployed at moderate transit speeds of up to 15 knots.

  • MCM-capable helicopter. This helicopter should be of modular payload design that could receive various sensor packages such as mine hunting LIDAR equipment, acoustic sensors and towed equipment, and mine sweep gear. Strong emphasis should be given to miniaturization and the development of physically lighter equipment to optimize the sensor payload mix.

  • Mine neutralization system. Building on current mine neutralization work, provide an expendable vehicle that can be deployed from either the ship or a helicopter, can sense a previously detected mine, and can place the required neutralization package on or near the mine. In this connection, it has long been demonstrated that 0.50 caliber standard projectiles can sink floating mines, and occasionally detonate them, but have limited water penetration, which makes them less useful against moored mines. RAMICS, using a supercavitating projectile with a pyrophoric charge, promises to solve both of these problems. In using a helicopter-mounted LIDAR for detection and aiming, the problem is to establish an accurate fire control solution at a range that permits the helicopter to stand outside the shrapnel envelope. Studies and tests thus far have been favorable.

Programs related to providing these capabilities include the following.

Airborne Laser Systems

The Navy's Magic Lantern Adaptation system, the Army's ASTAMID, and the Marine Corps' COBRA are all in the concept and development stages and are designed to detect mines in the surf zone, in the craft landing zone, and on land. For detecting mines seaward of the surface there are three competing laser-based technologies: the range-gated camera, the spot-scan, and a laser-stripe-type system.

The Magic Lantern system is based on a range-gated CCD camera. It provides better resolution in the horizontal plane than in the vertical direction (depth). It is primarily a shadow detector and can be used against floating or moored mines. The Magic Lantern Adaptation system mentioned above is based on Magic Lantern technology and addresses the minefield detection problem in the surf and craft landing zones. There are currently three Magic Lantern systems on

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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reserve SH-2 helicopters, and a system was deployed during Desert Storm. Integration into the active fleet would require that the sensor be modified to fit on the SH-60 helicopter.

Spot-scan technology, based on the photomultiplier tube, was originally designed for ASW but is being modified for the MCM mission. It uses a scanning spot beam to construct an image of the scanned area. The spot-scan approach provides fine resolution in the vertical direction but coarse resolution in the horizontal plane. The laser's pulse repetition frequency is a limiting factor on system resolution.

In addition to these approaches, a third, based on laser-stripe technology, is in an earlier phase of development. The laser-stripe approach, as embodied in STIL, uses a fan beam projection perpendicular to the direction of motion and a CCD array to provide fine resolution in the vertical and cross-track directions. The along-track image is formed by successive pulses as the searcher moves ahead. STIL holds the promise of fine resolution that may be able to detect bottom mines as well as those in the water column.

All of these systems take advantage of a notch in the attenuation curve in the blue-green optical region of the electromagnetic spectrum. Even so, attenuation is severe, and LIDAR systems will likely always be limited in depth. However, the depth ranges reachable are important for MCM, and in addition, such systems may be used to complement look-down sonar searches at lower depths.

Expendable Neutralization Vehicle

The mine neutralization vehicle now available to MCM-1 and MHC-51 MCM ships is the AN/SLQ-48 mine neutralization system, a deck-mounted vehicle launched and recovered by a winch and crane system.

The mine neutralization vehicle is subject to several limitations against the shallow mines that are now the focus of attention. Its forward progress and maneuverability are adversely affected by longshore and tidal currents. Because of its magnetic signature, it cannot approach a mine close enough for precise charge placement, and the cycle time from launch to recovery is excessive for the kind of clearance speeds required in modern scenarios. The launch-to-recovery cycle time after the mine has been detected and classified, and then the time required for the ship to back off to a safe range, combined with operations in daylight hours only, mean that an MCM- 1 can clear only about 12 mines per day. Further, there is no assurance that the mine has been neutralized, and, even if it has, a mine that looks like a mine on a mine hunting sonar is left to possibly create later confusion, along with an explosive charge weighing up to a thousand pounds that could later detonate by impact.

Despite these limitations the SLQ-48 has unique capabilities and should be retained for neutralization of mines in deeper water such as straits, the outer continental shelf, and shallower parts of the continental rise. The French PAP-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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104 would be better suited to shallow-water mine neutralization, but here, too, is a vehicle that must be launched over the side and recovered. What is needed is an expendable mine neutralization vehicle with a signature low enough to actually touch the mine without activating it, and with adequate terminal homing sensors to place a small cavity charge against the mine's main charge.

The old wire-guided Sea Nettle concept of the 1960s was an excellent early attempt to achieve the capability noted above. However, if the anecdotal record is correct, the program committed the fatal error of continuously adding capability until the system was priced out of competition.

Today, however, there is another chance to produce an effective and inexpensive expendable mine neutralization system. Fiber-optic cables have replaced the wire for guidance, LIDAR has been introduced and added to sonar for terminal homing and placement of a small neutralization charge against the explosive compartment of a mine, improvements have been made in small sonars, and miniaturization of electronics and sensor systems has increased significantly. The Navy should pursue the development of a small, low-cost, expendable mine neutralization vehicle for use by advanced mine countermeasures (AMCM) helicopters, small MCM surface craft, the MCM-1 and MHC-51, and in the future, all MCM-capable ships and air platforms.

Airborne Mine Neutralization System

The Airborne Mine Neutralization System (AMNSYS), currently in development, is intended to provide MCM helicopters with a mine neutralization capability. However, the airborne mine neutralization approach has limitations. The neutralization vehicle is lowered into the water and fiber-optically guided to a GPS coordinate provided by another helicopter towing a mine hunting sonar. Guidance by the launch vehicle to GPS coordinates is provided by a dipping tracker sonar. The neutralization vehicle, after reaching the near vicinity of the coordinates, must then detect the mine and home on it with its own sensors—whether sonar, TV, or LIDAR. Problems of target reacquisition are likely to arise because the GPS coordinates provided by the mine hunting helicopter are based on detection from a side-scan sonar towed at some distance from the helicopter. It would be better if the tracker sonar were upgraded such that the neutralizing helicopter, using GPS coordinates, could reacquire the contact before launch of the neutralization vehicle.

As an adjunct, consideration should be given to providing airborne systems with a variable-depth mine hunting sonar so that a single helicopter can do mine detection, classification, and neutralization as do MCM ships. Cost trade-offs, not technology, will be the determinant. The technology required for the neutralization vehicle is in place. The concern is keeping the costs down, ensuring that the cycle time (launch to detonation) does not exceed 10 minutes, and insisting on a sympathetic detonation of the mines.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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The Navy should take a fresh look at the design of an expendable mine neutralization system capable of being used, with minimal adjustment, by AMCM helicopters, by the MCM-1 and MHC-51 MCM ships, by designated MCM capable combatants, and by small MCM surface craft yet to be introduced.

Synthetic Aperture, Low-frequency, and Self-registering Sonars

These sonars can significantly improve the location and classification of mines in the shortest possible time and from a safe distance. In the panel's opinion, such sonars will be the central element in all future aspects of mine hunting, including reconnaissance, minefield mapping, mine avoidance, and mine neutralization.

Current long-range search sonars operate in the frequency range of 10 to 100 kHz with detection ranges of up to 2 km, but they have poor resolution and are therefore prone to high false-alarm rates. Higher resolution requires impractically large apertures. Medium-and short-range classification sonars typically operate at 100 to 1,000 kHz. They have better discrimination and therefore can eliminate a large proportion of the nonmine contacts, but their range is limited and their area coverage rate is low. It is possible to combine the long-range attributes of the lower-frequency sonar with the high resolution afforded by high-frequency sonars through the use of synthetic aperture techniques. Until now, the technological stumbling block has been the need for precise navigation control or enormous computing power to make self-registering methods practical. Today's technology provides the latter. DARPA has a program under way that is intended to demonstrate this capability. If successful, this technology is expected to become a key element in the realization of a truly organic fleet MCM capability. It is recommended that the MCM community monitor this program and adapt successful aspects of the technology to current and future MCM platforms.

Current side-looking sonars are unable to look ahead and could miss a target that presents a weak signal if the sonar was deployed in such a way as to look only once at each location and aspect. Synthetic aperture processing could mitigate this potential shortcoming because it necessarily involves multiple passes over the same location at various aspects.

Brute Force—Breaching and Clearing the Surf and Craft Landing Zones

Brute force methods are generally those techniques that attempt to remove or clear mines en masse, using a nondiscriminating force that can physically overcome or remove them as an effective threat. Brute force methods are needed when the threat is so dense and time lines are short, where friendly forces are denied access to a mined area that needs clearing, or where the harshness of the environment prevents other MCM operations. Brute force methods, because they

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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do not depend on specific characteristics of the mine such as its signature or fusing method, are also a hedge against undetectable, difficult-to-spoof, stealth mines; unknown future mine technology developments; or even simple mines with very high ship counts and interlook dead periods. Although they are sometimes not highly technical, brute force breaching methods may require complex engineering, precise timing and fusing of explosives, development of unique chemical systems, applications of GPS and other locating and mapping methodologies, and high reliability.

The technologies, concepts, and systems discussed here must be developed to provide the path from the surf zone (10 to 15 feet) to the craft landing zone and up the beach, where there is a proliferation of mines and a dramatic increase in their density. In addition, minefields in these regions are usually mixed with several types of obstacles. Methods for breaching the surf and craft landing zones too often ignore the obstacle problem.

The panel has singled out two brute force technologies and techniques that appear to hold the most promise: (1) explosive channel excavation and (2) the use of causeways made of rigid polyurethane foams. The former relies on accurately placed bombs with timed explosives to clear mines and obstacles; the latter provides a means of bridging the minefield rather than clearing it. Other relatively simple mechanical and explosive approaches that should be considered for application in certain situations are also described. The two major technologies that are of the highest priority are discussed below.

Explosive Channel Excavation

The 1992 Naval Studies Board Mine Countermeasures8 study suggested that a buried line charge analog could be formed by airdrop or ballistic delivery of spaced bombs, penetrating to about the depth for maximum cratering radius, and detonated nearly simultaneously to form a cleared channel by excavations of mines and obstacles in the SZ and CLZ, and on up the beach. Although listed here as a brute force technology, it involves precise spatial and temporal placement of the explosive charge and high reliability of detonation. The requirements for precision are not so high in the vertical dimension because of the wide maximum in crater radius as a function of depth of explosion. Specifically, it was estimated that penetrating bombs with 10,000-pound TNT-equivalent explosives,9 spaced about 60 feet apart, buried to about 20 feet below the sea floor, and

8  

Naval Studies Board. 1992-1993. Mine Countermeasures Technology, Vol. I-IV, National Academy Press, Washington, D.C.

9  

During World War II, about 500 bombs of this size were used by the Royal Air Force's 617 squadron with much success, including the final capsizing of the Tirpitz. B52s, according to Boeing, could carry one under each wing. Cargo aircraft could also release a drogue-pulled string. The Soviet "Granit" self-alignment scheme for bomb patterns might also be used. On the ballistic side, missile tests in the 1980s demonstrated delivery of a 15,000-pound warhead at 300 miles.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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detonated to within 0.01 second of each other could excavate a 50-yard wide channel in which the bottom would be lowered 10 to 15 feet. The channel could be extended up the beach and would fill with water so that assault craft could ride to the end beyond the defended zone. Subsequent work by the Naval Surface Warfare Center including a test at the UK Shallow Water Test Range using four spaced, buried bombs has confirmed the scaled dimensions, the effective removal of mines and obstacles, the formation of sizable berms on the channel sides, and the absence of a large lip at the channel end.10

LLNL has proposed independently that patterns of available bombs could be used to excavate cleared channels11. Thus a double lane of 2,000-pound bombs, buried about 5 feet deep and spaced about 30 feet apart, if a 30-foot circular error probability is assumed, could form a 100-foot (lip to lip) channel 10 to 15 feet in depth from which most mines and obstacles have been removed. The Panel on Weapons discusses this concept in Volume 5: Weapons of this nine-volume series, adding the feature of proofing the channel by heavy line charge detonation after emplacement by robotic advanced amphibious assault vehicles (AAAVs).

Experiments at the Coastal Systems Station in Panama City, Florida, have demonstrated that mines and obstacles can be pushed away to form a clear channel by sequential positioning of bottom explosives to systematically provide momenta away from. The previously cleared area, in sufficient depths of water in the time between sequenced explosions, is affected by water motion in the surf zone. An analogous concept could probably be applied to sequential excavation in shallower water and up the beach.

In very shallow water, which is defined as the depth zone from 40 feet to between 10 and 15 feet deep, the threat is not expected to involve obstacles or very hard mines, and the mine density is expected to be lower than in the SZ and CLZ closer to shore. Mines in the very shallow region could still be buried, however, and there is always the possibility that increasingly stealthy mines will become available to potential adversaries. Explosive excavation could be effective in this zone, but the amount of ordnance required would be large because the very shallow water zone is typically far more extensive than the surf and craft landing zones.

The concepts described above, some in ongoing programs (e.g., line charges discussed below) as well as pulsed power, can be included under the generic concept of space- and time-controlled explosive patterns. If significant increases in the yield per unit mass of explosives become available, the practicality of all of these techniques will be enhanced. Further, modeling and simulation will be

10  

Furr, W., R. McKeown, and L. Taylor. 1996. ''Mine and Explosive Breaching by Explosive Excavation," presented at the Technology and the Mine Problem Symposium, Naval Postgraduate School, Monterey, Calif., November 18-21.

11  

Clarke, Douglas B., and John W. White. 1997. "A White Paper on Surf Channeling," Lawrence Livermore National Laboratory, Livermore, Calif., February 14.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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applicable to design of the explosive characteristics space-time pattern to obtain the best results and to facilitate operational planning for their use. Some of the data required to better understand explosive excavation phenomenology could possibly be obtained through experiments and modeling using a high-g centrifuge.12

Foams

The panel was impressed with DOD-funded work done at Sandia National Laboratories on petrochemical-based binary compounds that has led to the development of quick-setting rigid polyurethane foam. The chemicals, transportable as liquids, when mixed and exposed to air form a relatively tough, quick-setting, and rigid structure that floats on water. The volume expansion between the component liquids and the final rigid foam is a factor of 20 to 60, and the resulting structure has a bearing strength sufficient to withstand the repeated passage of vehicles, including tanks (in tests, passage of more than 50 tanks with a rut depth that did not exceed 12 inches). These foams have been demonstrated to withstand projectile impact and detonation with attenuated damage patterns, and tests indicate that they are not structurally weakened by bullets. Foams now in use will burn, but the resulting fire has been shown to be self-extinguishing. Tests also indicate that the foam can absorb some explosive blast energy. The foam will also incapacitate the sensors on pressure and tilt-wand mines, if the mine is engulfed in and immobilized by the foam; will provide a standoff for magnetic mines; and will reduce the profile presented by obstacles to assault traffic.

Although still in the developmental stages, this technology may have significant operations benefits. Many brute force techniques require significant maritime lift capacity, which offsets the space available to carry amphibious vehicles and other war fighting equipment. The foam system, if successful, has the advantage of being transported in an easily handled liquid form with minimal space requirements. Preliminary tests indicate that a foam road can be built in shallow water out to the surf zone.

Following are some other brute force methods involving explosives.

Explosive Nets and Rocket-propelled Line Charges

Now in the R&D program, these are methods for neutralizing mines in the surf and craft landing zones, with application to land minefields as well. The rocket-propelled line charge, known as SABRE, is a line thrown ahead from a

12  

See, e.g., Holsapple, Keith A. 1994. "Catastrophic Disruptions and Cratering of Solar System Bodies: A Review and New Results," Planetary and Space Science, 42, no. 12, pp. 1067-1078.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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landing craft, air cushioned (LCAC), by a rocket motor; the explosive net, known as DET, is a net with neutralizing charges at mesh corners (the net itself may be made of primacord) capable of being rocket propelled into place in the same manner. Both are adaptable to use against land mines. There is a net version that can be deployed by air, known as Thunder Road.

Both systems are sound, but given the demanding conditions of the initial phase of an amphibious assault, both have disadvantages. The delivering platform must be brought close to the mined area prior to launch; the logistic load is burdensome where multiple shots are required; the lateral neutralization distance is limited by the upward focusing of ground level explosives; and both will drape over obstacles, possibly leaving mines beneath the drape undamaged if the depth of draping is too shallow or out of the water.

SABRE and DET should be developed for breaching both land minefields and the surf and craft landing zones where obstacles are not present. Particularly against land minefields, the Thunder Road and glide net concepts for aircraft delivery have merit and should compete for selection. The objective of a 1,000-foot launch standoff for both SABRE and DET appears reasonable and attainable.

ATACM Block 1

Missiles, such as the Army Tactical Missile (ATACM) Block 1 with a range of 75 miles and carrying 950 bomblets, represent an interesting variant on the DET concept for clearing both land mines and sea mines in the SZ and CLZ. Pattern control is an obvious problem, as are comparative costs. Further, current designs incorporate antipersonnel bomblets that would have to be redesigned for use against mines. Given its standoff range and speed of delivery, however, it is a concept worthy of further analysis. The ability to fire ATACMs from a Navy ship has been demonstrated.

Mechanical Methods

In the past, a number of mechanical devices have been used with varying degrees of success against both land and sea mines, and several modern versions of some of these devices are under development today. Such devices have consisted of vehicle-mounted flails, rollers, and plows against land mines and obstacles, and trawls against shallow sea mines. A detailed description of mechanical methods is given in Appendix E.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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THE FAR TERM: TECHNOLOGY AND CONCEPTS

Next-generation MCM Platforms

There is a need to develop a replacement system for the current classes of mine hunting and mine sweeping ships and helicopters to accommodate the Navy's future roles and responsibilities and to take advantage of new MCM technologies. Helicopters with improved, lighter, MCM sonars, LIDARs, active magnetic or mechanical and acoustic sweeps, and possibly supercavitating projectile mine killers will be an important element of future MCM capability. The future MCM helicopter will have a modular payload capability so that it can be rapidly configured to meet special demands. Surface platforms will be small, stable, long-endurance, unmanned platforms, possibly based on SWATH technology, possibly stealthy, towing sonars under remote control. Underwater platforms will include swim-ahead UUVs with mine detection, classification, and neutralization capability. The panel anticipates the development of a specially configured MCM support (Catskill-like) ship, with battle force speed, MCM command and control capacity, and the capability to transport and maintain small MCM ships and helicopters having characteristics such as those outlined in Table 2.1.

The concept of operational employment for the new MCM support ship and embarked MCM assets is to deploy them with either a battle group or an amphibious ready group, depending on time requirements. This will provide an MCM capability in transit, in-area surveillance, hunting, sweeping, and neutralization. If positioned remotely from an emerging need for MCM operations, the support ship with its embarked assets will be able to transit immediately and at battle group speed. In the event the MCM support ship is not available prior to the battle group's need to move, the recommended organic MCM capabilities will allow safe and rapid transit.

Modern Catskill Concept

The panel considered specific support ship and small MCM ship designs applied to a modern-day version of the Catskill concept. Over its long history the MCM force has repeatedly demonstrated that the countermeasure functions of mine sweeping, mine hunting, and mine neutralization can be carried out by air and surface platforms much smaller than the 1,300-ton MCM-1 carrying a crew of 83. The Inshore Minesweeper (MSI), mine countermeasures ship (MCS), and Minesweeping Launch (MSL) of the 1960s, which ranged in length from 36 to 110 feet, clearly demonstrated the fact, and AMCM helicopters are a more recent example. Craft of opportunity have been an enduring example, as well. In designing a future MCM force organic to the fleet, the Navy should capitalize on the proven capability of smaller platforms and take full advantage of all reduc-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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tions in the weight, volume, and drag of MCM systems allowed by modern technology.

The use of the minimum-size surface craft required to carry out the MCM function has two disadvantages that must be mitigated: they have limited seakeeping capability, and they must be transported to the site of conflict. In the early 1960s an important attempt was made to deal with these problems. Two 9,000-ton logistic support vehicles, the USS Ozark and the USS Catskill, were converted to MCS ships. In addition to a landing pad and a hangar for two AMCM helicopters, the MCSs were equipped to carry 20 MSL MCM craft. The MSL was a 36-foot open launch (Boston Whaler type) equipped for mine sweeping using light AMCM sweep gear, mine hunting using a strap-on AN/SQQ-16 variable depth sonar, and mine neutralization by vectoring a charge lowered from a small boat. However, the concept had one serious and one fatal flaw. The MSL turned out to be a very wet boat, which limited its operations to sea state 2 and below, and the MCS was top heavy due to the 22 MCM platforms carried at or above the main deck. Unfortunately, these shortcomings resulted in the abandonment of what could have been powerful and cost-effective MCM platforms.

The shortcomings in the earlier implementation can easily be overcome with current technology. Utilizing a SWATH hull form, an MCM craft of the general size of an MSL (i.e., 36 feet in length) can perform the full range of MCM functions, operate in sea states 3 to 4, and survive in higher seas.

The more important mission of the small MCM platform is expected to be mine hunting, although it would have a mine sweeping capability utilizing either lighter AMCM sweep gear, or influence gear such as that being considered in the Advanced Lightweight Influence Sweep System (ALISS) research program. The sonar would be a variable-depth type about the size of the modified SQQ-14 or smaller. An expendable mine neutralization capability would be provided. Platforms of varying sizes could be built or reconfigured to fulfill the requirements of transporting, supporting, and acting as the command and control element in MCM operations. The support ship might be capable of carrying 2 to 10 of the small MCM vehicles and also possess helicopter deck space and support areas. The precise configuration and size of the support ship will depend on a detailed analysis of the concept of operations for these platforms.

Pulsed Power

The use of intense acoustic or shock waves to disable mines at safe standoff and also destroy obstacles and barriers represents an attractive concept for MCM. Pulsed power is an application of space-time distributed explosive energy, produced by electrical discharges, chemical reactions (small explosions), or other methods, to produce focused acoustic or shock energy. The idea is similar to, but on a much larger scale than, the successful application of focused acoustic shock waves to kidney and gallstone therapy—known as lithotripsy—wherein the cal-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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careous stone is destroyed by repetitively subjecting it to a shock waves, which eventually break it into pieces small enough (in the case of a kidney stone) to be passed painlessly via normal urination.

The range at which sufficient energy for mine neutralization can be brought to bear will be an important consideration for the protection of platforms from which any pulsed power device is deployed. A number of approaches using a variety of source technologies have been proposed. These include, most recently, chemical explosive arrays to form shock pulses and spark discharge pulses from either a single source or a phased array of sources. Two concepts of operation have been considered. In one, low-power pulses are transmitted, and the returns are received by an acoustic receiver array and analyzed to indicate the location of a target in a manner identical to a conventional sonar. A pulsed discharge array, at higher power, can then be focused on the target.13 A second, more recent concept involving explosives simply generates high-power pulses in a beam that advances with the motion of the source vehicle, clearing mines and obstacles in the way.

At the time of this writing, DARPA is conducting a program to address the critical issues and assess the practicality of the method. These issues include determining if nonlinear wave superposition works in the same sense as linear superposition, thus resulting in the assumed 10 log N array gain and, if so, determining whether in practice shock sources can be timed or appropriately phased. If focusing is used, the sharpness of the focal point itself is important and would have to be modeled with nonlinear acoustic models. The effect of in situ bubbles, especially dense in near-shore areas, is unknown (a 1 percent void fraction can double acoustic attenuation). The effects of cavitation bubbles produced by the shock wave itself on subsequent shocks that must pass through the cavitated water are also unknown. Multipath propagation and surface and bottom reflection and scattering will also affect focusing on the effective beam geometry. The destructive mechanism for mines is not certain, nor are the required pressure and impulse. Repetitive pulses may be required to destroy some kinds of mines.

There are implementation considerations as well. There are limitations in pulsed power to avoid damage to the carrying vehicle and source array, as well as limitations due to water depth and required standoff distances; there are also limits in pulse shaping and repetition frequency because of source characteristics and between-shot recovery times.

Although the list of issues that have to be addressed to assess the future application of this method is seemingly long, and there are concerns regarding the physics of nonlinear wave superposition in water and the effects of limited depth and irregularities in the propagation medium, initial results from the DARPA

13  

Although it was not presented to the panel, the Navy has apparently evaluated the electric spark approach as requiring heavy equipment to achieve mine detonation at acceptable ranges.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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program are encouraging. At this point a systematic measurement program to acquire necessary data is required. If this technology can be developed for effective use by MCM forces, it could significantly multiply current capabilities. As mentioned above, feasibility studies are currently under way and, if the technology proves feasible for operational use, further development should be pursued.

Autonomous and Semiautonomous Networked Undersea Systems

The most pressing need is to extend the reach of MCM sensors without putting humans in harm's way. While requiring advances and development beyond those currently possible, technological progress in sensors, signal processing, and computational power will make autonomous and semi-autonomous systems possible. Networked undersea surveillance systems using small, autonomous and/or semi-autonomous undersea vehicles could significantly enhance covert mine surveillance, detection, and neutralization capability.

Such vehicles would posses a hierarchical intelligence, and varied capability; they would be able to communicate with each other and with command-and-control nodes via Internet-like circuits. They would operate autonomously, reporting only when interrogated or programmed to do so. Autonomous vehicle systems could be combined with other distributed sensor systems, perhaps predeployed in an area of interest.

Vehicle technology pursued in past UUV programs14 provides a basis for future efforts. New energy sources, propulsion methods, automatic target detection algorithms, and methods of underwater navigation and autonomous control will make the UUV an ever more practical adjunct to MCM operations. Within the time horizon of this study, it is expected that undersea communications technology, acoustic or otherwise, with adequate data transfer rates, will be available.

Multiple vehicle approaches that exploit the efficiency of systems operating in parallel might involve stealthy vehicles or small, bottom crawling robots that detect mines, attach themselves to them, and then at a later time, perhaps on command, neutralize them. Such small autonomous or remotely controlled devices might be effective against very shallow water (VSW) mine fields, perhaps using the electrical resistivity method (discussed below) to sense buried metallic and nonmetallic mines. Neutralization of buried mines requires investigation. In-water use in the SZ may be limited because it is relatively easy to construct simple and inexpensive barriers between their launch point and the minefield. Nevertheless, it is clear that robotics has a strong future role to play in MCM, and research in this general area should continue. The viability of alternate ap-

14  

National Research Council. 1996. Undersea Vehicles and National Needs, National Academy Press, Washington, D.C.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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proaches will depend on specific requirements, concepts of integrated operations, possible counter-countermeasures, and the existing state of critical vehicle technology development.

Mammal Adjunct to the Small Unmanned MCM Ship

None of the minefield reconnaissance systems discussed thus far are capable of detecting buried mines, yet mines buried by natural means are likely to be encountered in those littoral regions where shoals are forming. Currently, only the Mk-7 mammal system is capable of detecting and placing charges to neutralize buried mines. Combining the Mk-7 with a small, enhanced-capability MCM vessel could provide a system that can be launched from over the horizon, that operates in sea states 3 to 4, and that is able to detect, classify, and place timed neutralization charges against moored, bottom, and buried mines into the surf zone. The effectiveness of neutralization of buried mines by charges on the bottom requires investigation.

If some of the advanced reconnaissance systems described in this report become available, the preferred use of the small MCM vessel Mk-7 system would be to proof channels already selected on the basis of earlier reconnaissance against buried mines and to place neutralization charges on or above all mines in the channel. Its use in this fashion moves the operation closer to the assault launch hour, by which time control of air, sea, and near-shore defenses has presumably been established.

Swimmer Electrical Resistivity Detection System

Minefield reconnaissance by swimmers (sea, air, land [SEAL] teams), particularly in depths between 60 feet and the surf zone, is effective but limited in search rate and incapable of detecting buried mines. To augment this capability the panel recommends that the electrical resistivity method suggested by the JASON-5 committee during the time of Desert Shield be evaluated. Electrical resistivity has long been used by the mining industry to detect buried ore bodies and other subsurface anomalies. The JASON15 suggested that it be evaluated for use in the detection of moored (by their anchor), proud, and buried mines, both metallic and nonmetallic.

The JASONs hypothesized an array of electrodes about 6 feet long.16 The

15  

The JASONs are a self-nominating academic society that conducts technical studies for the Department of Defense (meets in July, August, September, and October and produces a report in November).

16  

The vertical (downward) dimension of the electrical field is several times greater than the spacing between the two current-carrying electrodes. Since the targets to be detected (mine anchors, proud mines, and buried mines) would be either resting on the bottom or buried by no more than a few inches, the distance between electrodes would not have to be more than 6 feet.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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two outer electrodes (one at each end) would carry current, thereby establishing an electric field, which would be monitored by the inner non-current-carrying electrodes. The upper surface of the array would be insulated to prevent interference by surface waves. Metallic mines will register as an increase in conductivity, and nonmetallic mines will register as a nonconducting anomaly within the field. Detected anomalies would be correlated and analyzed by a small computer. Although false contacts may be a problem in some areas since the method is unlikely to allow positive classification, in the absence of any alternative for swimmer detection of buried mines together with the capability to detect both metallic and nonmetallic mines, the electrical resistivity method may provide a useful capability. The electrode array could also be mounted on a UUV.

Biosensors: Mammal Sonars

There are many ways of reducing the signature of a mine to make it less detectable, such as using materials and shapes that blend in with the environment, constructing it of nonmagnetic materials, or designing it to have a low acoustic cross section. Existing mine hunting sonars have a very difficult task detecting reduced-signature mines, and in the short term, the Navy may be forced to rely on sweeping and brute force methods when such mines are known to be deployed. However, in the long term, future detection systems are expected to counter this problem. The reason for optimism lies in the performance of biological sonars, such as those of dolphins. These mammals are able to detect prey by sonar, even small fish that have much lower signatures than any mine and can conceal themselves by burrowing in the sediment. In many ways, they outperform hardware. They are the most (perhaps only) effective system available for finding buried mines. They are effective in locating, identifying, tagging, and charge placement. Unfortunately, however, their range (>20 km) and endurance system are limited, they are sensitive to temperature, they have stringent on-site handling requirements, and they pose difficult logistical demands. It may be possible for potential adversaries to engineer mine signatures in such a way as to make detection by marine mammals more difficult, but given the limited use of mammal-based mine hunting systems, it appears unlikely that any nation will go to this expense in the near-term.

All of these shortcomings could be overcome if the features of mammal sonars were incorporated into hardware. Since 1959 there have been a number of small research programs with this objective, but little has found its way into practice. For example, mammal sonars are known to adapt, presumably in some optimal sense, to the environment in which they operate. They change pulse types, durations, and frequencies. They use two ears, and they approach targets and view them from several aspects. These notions have had only elemental incorporation into sonar system design.

It is not unreasonable to postulate a man-made sonar with the same capabili-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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ties as a mammal sonar, especially with the growing understanding of cognitive processes and the development of systems such as neural networks that mimic them. The payoff in vastly improved sensor performance is so great that research aimed at revealing the mechanisms of biosonars with an aim toward emulating them should be given high priority.

Active Electromagnetic Mine Detection

Pulsed electromagnetic induction is a methodology that has been employed successfully in geophysical prospecting for conductive ore bodies. It is an active electromagnetic technique whereby a primary magnetic field is used to induce currents in nearby conductors. The currents decay because of resistive losses, creating secondary magnetic fields that are detected above Earth's surface. The rate of decay of the secondary field contains information about the size, conductivity, and magnetic permeability of the object. Although the application of this approach to mine and submarine detection was investigated by the Naval Ordnance Laboratory in the 1950s, recently a new processing technique using holographic imaging has shown considerable promise. It is recommended that progress with this technology be closely monitored and applied to MCM systems as appropriate.

OFFENSIVE MINING

The Case for Offensive Mining

At present, a segment of the naval community questions whether, in the high-technology weapon environment we are now entering, the Navy will have a need for mines in the future. Yet there has not been a time since the 1930s during which the Navy has been more in need of mines to leverage a reduced fleet with expanded global responsibilities. First there is the deterrent value of a credible mine stockpile and the ability to deliver it—covertly, if necessary. The deterrent value of that stockpile will be measured by the sophistication of its content and the adversary's uncertainty of being able to counter the mine types it contains. There is also the need to be able to supply our allies with effective mines to provide for their own defense or to slow down an assault until U.S. forces can arrive. Taiwan and South Korea come to mind, although both have the technical ability to design superior mines on their own.

Perhaps the Navy's greatest need for mines in the present environment is for effective blockade of strategic ports and straits without the need for exposing lives and high-value targets to defensive action. With reductions in force levels there is justifiable concern on the part of both the Navy and the Marine Corps regarding the ability to handle two simultaneous medium-level conflicts. In those scenarios in which the aggressor's ambitions are based in significant part

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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on the use of naval forces, mines could be useful in stopping or seriously delaying such aggressive action until additional force can be brought to bear.

The growing dependence on submarines around the world and the slow but steady increase in the proficiency of their crews signal a serious problem for the Navy and Marine Corps team in any future attempt to project power against the land. Advanced mine designs capable of protecting the flanks of an amphibious assault force from submarines will significantly leverage the available combatants. Such mines could be equipped for preset explosive self-destruction when their job is done.

Near-term Needs and Recommendations

Sustaining a Mine Design Team

One of the many casualties of the post-Cold War downsizing has been the mine design capability so long resident at the old Naval Ordnance Laboratory at White Oak, Maryland. The White Oak team, in which resided the expertise and corporate memory accumulated since World War II, has been reduced to token representation of mine design specialists and supporting documentation at the Coastal Systems Station in Panama City, Florida.

The Navy and Marine Corps will need a small mine design team composed of the most highly qualified scientists and engineers it can attract to the job in order to (1) assist the technical intelligence community in interpreting new, and often fragmented intelligence data; (2) analyze and help develop countermeasures to foreign mines; (3) prevent technological surprise; (4) conduct research from which the Navy can select its future mines; and (5) serve as a Red Team for the MCM research and development community. The panel strongly recommends that such a team be built around the token element now resident at the Coastal Systems Station.

Remote Command and Control

With the placement accuracy made available by GPS navigation, it is now possible to lay offensive minefields in order to prevent defensive mining and yet leave unmined channels for use by our own forces. This technique has long been suggested but, due to navigational uncertainties, considered too dangerous to our own forces to be implemented. The alternative, of course, would be to develop a remote command and control of mines feature of such reliability that our own forces would pass over a command-off minefield with confidence. Commanders, particularly those of high-value ships, have been reluctant to accept this technology over the past 25 years. However, there appears to have been no hesitation in passing over the controlled minefields used to protect Allied harbors in World Wars I and II or the one used by Norway throughout much of the Cold War. The

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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difference between the old and trusted system and the yet-to-be-trusted new system, besides vastly improved electronics in the latter case, is that the old system had a man in the command-on-command-off loop.

Littoral Sea Mine

To fill and improve on the void to be left by the Mk 56, the Navy should seriously pursue a littoral sea mine (LSM). A mission needs statement currently exists for such a mine, and an advanced technology demonstration (ATD) has been proposed by the Navy and industry. The prototype LSM will consist of a three primary subsystems: (1) a target detection system that leverages ongoing sensor technology demonstration efforts; (2) a mobile homing warhead that uses the lightweight hybrid torpedo currently being developed; and (3) a subsystem that leverages ONR's deployable autonomous distributed system technologies.

The target detection system will provide the capability to detect, localize, and track targets in the littoral environment to within the lethal zone of the lightweight hybrid torpedo. It will consist of a multi-influence passive detection subsystem and an active target verification subsystem. The passive detection subsystem will acquire and process target signature data and initiate the transition to the active acoustic verification mode. The active sonar will transmit low probability of target alertment pulses to make multiple range and bearing determinations until a target track converges with sufficient quality to verify that the target is within the mine's lethal zone. The target detection system will then activate the mobile homing warhead, pass targeting information to the vehicle, and prepare it for launch.

The primary function of the mobile homing warhead is to deliver a bulk charge warhead from the mine's deployed position to within the mission abort damage range of the target and to detonate the warhead at the appropriate time. Using the lightweight hybrid torpedo as the mobile homing warhead payload utilizes the speed, maneuverability, and zone-homing performance of the torpedo. This will increase the mine's lethal-zone-coverage capability over that of the Mk-56 mine. Also, since the lightweight hybrid torpedo can be vectored in azimuth from a vertical launch, which was not possible with the encapsulated torpedo (CAPTOR) mine using the Mk 46 Mod 4/6 torpedo, a single mobile homing torpedo can cover many target volumes. A RECO subsystem will provide the capability to control an LSM field from a surface or submarine platform.

The Marines and the Modern Homing Mine (HOMINE)

The Marine Corps depends largely on the Army for its land mines and the countermeasures to such mines, and for that reason, as noted in the Preface, this report deals mainly with sea mines and mines in the surf and craft landing zones. It appears, however, that evolving Marine Corps strategy and tactics for land

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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combat (i.e., many light, small units, widely spread, very lethal, and highly maneuverable) will generate requirements for both land mine and land mine countermeasures that differ from those of the Army.

In the late 1960s and early 1970s, the Army developed to the prototype stage a distributed sensor antitank minefield called HOMINE. The sensors were small, inexpensive, easily scatterable devices consisting of either a pressure or a magnetic sensor and a simple radio transmitter. The radio signal was coded, and all sensors for a given kill system had the same code. When approached (or run over in the case of the pressure sensor) by a tank or armored vehicle the radio transmitter emitted a single, coded burst. The radio burst gave no indication as to which sensor had activated or where within the field the target was, but this was not needed. The multiple-shot kill system was concealed centrally within the sensor field, or centered along its periphery, and consisted of a short grain solid rocket motor, an IR sensor, a warhead, and limited control surfaces. On receiving a signal from one of the sensors the rocket boosted the kill system such that it coasted to a stop at an altitude of 1,000 feet, turned over, detected the target with its IR sensor, and glided to impact. For reasons unknown to the panel, HOMINE was dropped before reaching service use.

It may be wise, however, for the Marines to examine the HOMINE concept with an eye toward further miniaturizing both the sensor and the kill system using modern technology. A variety of such broad-coverage systems that place little weight on the logistic burden is possible.

Far-term Needs and Recommendations

Mine Delivery

Any consideration of the future emphasis that should be placed on mines is incomplete without considering the deliverability of such weapons. Today, virtually all of our mines are delivered by either submarines or aircraft. U.S. forces have no surface ships uniquely configured for mine laying, and for a very good reason. The advantage of such ships diminished as the transition was made from the cumbersome Mk-6 type moored mines that had to be trundled around on their own wheels to the more easily handled bottom influence mines and more efficiently designed moored mines. Most modern mines can be laid by practically any surface ship, as demonstrated by the former Soviet Union and by such countries as North Korea, Iran, and Iraq. The Navy's lack of attention to surface ship mine laying has been due primarily to the fact that the emphasis has been on offensive rather than defensive mining, where the advantage of the surface ship and its delivery capacity are greater. Let us assume, then, that the Navy's emphasis in mine laying will continue to be on the submarine and aircraft and that the surface ship can be pressed into service without undue modification.

The main advances in mine deliverability will come from the mines them-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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selves, not from new aircraft and submarine designs. Specifically, advances will come from the continued miniaturization of electronics and from the introduction of explosives with greater energy yield. As an example, the old Mk-55 mine was 21 inches in diameter and 114.6 inches long (the instrument section took up about 20 percent of this length), weighed 2,196.5 pounds, and carried a 1,270-pound explosive charge. Using modern electronics and case material and merely doubling explosive energy yield (considered attainable during the projection period of this study) would produce a mine with improved performance and equivalent destructive capacity, but that would be only around 45 inches in length and would weigh about 700 pounds. Thus, it appears possible, without heroic efforts, to cut the mine delivery sortie requirements of both submarines and aircraft by more than half. Also, if the tubes on a retiring SSBN could be used for mine laying (now being considered for the Tomahawk missile) each D-5 tube could carry roughly 35 mines, or a total of 840. Such a size and weight reduction also introduces the possibility of the delivery of sea mines by rocket, which is now done with land mines.

Networked, Controllable Minefield

With the projected advances in sensors, processing, and communications technologies, an advanced concept of an intelligent minefield appears feasible for the future generation of sea mines. Envisioned is a networked laydown of individual mines that can communicate to pass information and data and to utilize effectively the distributed sensor information they collectively obtain. In addition to the increased performance obtainable from distributed surveillance, the minefield could be designed with sufficient intelligence to achieve remote failsafe command and control and selective targeting. This attribute could reduce the current aversion to mining conceived as a distribution of indiscriminate lethal weapons.

The networked minefield concept includes the notion of separated detection or targeting sensors and attack weapons. This would permit the cost-effective laydown of separate detection nodes and connected weapons tailored to the requirements of the local environment and threat picture. The technology enablers for multi-influence detection sensors—distributed processing, networked communications, intelligent control architectures, and lethal attack mechanisms—should be pursued. The networked, controllable minefield has the potential to mitigate concerns regarding indiscriminate mining and has the flexibility for tailored deployment that can provide significant cost savings.

CROSS-CUTTING TECHNOLOGIES

This section deals with several technologies that are applicable to a wide spectrum of mine warfare and mine countermeasures issues.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Modeling and Simulation for Mine Warfare

The Navy and Marine Corps, as well as the other Services and DOD, are becoming increasingly dependent on the rapidly expanding field for the design of weapons and their countermeasures, for their evaluation, for the development of tactics and doctrine, for training, and as an aid in procurement decisions. This subject area is comprehensively addressed by the Panel on Modeling and Simulation in Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a -Century Force, Volume 9: Modeling and Simulation. As with any application of modeling and simulation, modeling and simulation aids for mine warfare should rest on a sound theoretical basis. Unfortunately, developing such a basis is not straight-forward because the underlying mathematics are difficult and require an understanding of probabilistic dependencies. In the past, workers have developed models for estimating the effects of minefields or mine countermeasures that, although seemingly sound, have in fact been highly misleading (see Appendix J, ''Probabilistic Dependencies in Combat Models," in Volume 9: Modeling and Simulation).

Configural Theory

Configural theory, developed by a small research group working under contract for the Navy, is a mathematical theory that quantifies the relationships between the behavior of weapons in use in combat and their individual characteristics. Its principal purpose is to provide concepts and mathematical relationships to improve understanding of the behavior of weapons in combat and of their combat effectiveness. Its name is derived from its central concept, configuration, which is the mathematical expression of the fact that the disposition in space and time of the targets and weapons of the attacker and defender influences the outcome of the engagement and the combat effectiveness of those weapons.

Among the conclusions from the research17,18 conducted thus far are the following: (1) nonconfigural representation of target-weapon encounters may be suffi-

17  

Horrigan, Timothy, J. 1992. "The Configuration Problem and Challenges for Aggregation," pp. 102-153 in Proceedings of the Conference on Variable-Resolution Modeling, Washington, D.C., May 5-6, CF-103-DARPA, Paul K. Davis and Richard Hillestad, eds., National Defense Research Institute, RAND Corporation, Santa Monica, Calif.

18  

Horrigan defines configural theory as "a mathematical theory for quantifying the relationships between the behavior of weapons in use in combat and their individual characteristics. Its principal purpose is to provide concepts and mathematical relationships to improve our understanding both of weapon behavior in combat and of combat effectiveness. Its name is derived from its central concept, configuration, which is the mathematical expression of the fact that the disposition in space and time of the targets and weapons of the attacker and the defender is inseparable from the outcome of the engagement and the combat effectiveness of those weapons."

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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cient to invalidate a model or simulation; (2) Lanchester-theory-based representations, deterministic or stochastic, are generally nonconfigural; (3) the conception of weapons effectiveness and the derivative mathematical models, particularly those based on initial threat and free encounter (independent event), may be inappropriate; and (4) nonconfigural assessments may, in some instances, significantly overstate weapon effectiveness and make less effective weapons appear preferable to more effective weapons.

Configural theory is an approach to mine warfare analysis that permits development of a comprehensive and reasonably correct model system encompassing relevant characteristics and interactions, including spatial, temporal, and entity-specific relationships. It has generated a new family of meaningful measures of effectiveness. Simpler analytical models that form the basis of tactical decision aids currently in use for mine warfare applications do not properly account for probabilistic dependencies and entity-specific relationships (see, for example, Appendix J in Volume 9: Modeling and Simulation in this nine-volume series). Not surprisingly, the application of configural theory requires greater rigor and time than nonconfigural models, but its use would enable a significantly better understanding of mine warfare and thus help to optimize the allocation and application of mine warfare resources.

New Modeling and Simulation Tools

Advances in computer memory, processing power, networking, and visualization have dramatically improved modeling and simulation capabilities. These technologies offer revolutionary advances in the simulation of military operations and high-detail interactive representations for design and manufacture. Organizations involved with traditional exercises, training simulators, computer simulations, war games, system design, and test and evaluation are beginning to experiment with these new tools. Two key issues are how much to invest and where. A key concern is verification, validation, and accreditation (VV&A).

The key benefits of the new modeling and simulation technologies are bringing the operator into the simulation and providing necessary linkages such as those between designers and operators, different members of a unit, different units of a force, and so forth. For the MCM community, four key applications are possible: (1) integrating MCM into Navy and Joint Force planning for acquisition and operations; (2) improved tactical development and training despite geographic separation of the principal MCM forces from the fleet and dispersal of the reserve component; (3) the timely development of appropriate systems to counter a threat that is rapidly changing, increasingly sophisticated, affordable to all potential enemies, and likely to be encountered in difficult coastal environments; and (4) improved understanding of the environments relevant to MCM in the littorals.

The key challenges to realizing the promise of the new modeling and simulation tools for MCM are the selection of appropriate focal points for investment,

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

adapting emerging technologies to these focal points, acquiring supporting databases, and designing a VV&A program that will build confidence in the tools and establish their effectiveness.

Environmental Characterization

The effectiveness of MCM sensors is critically dependent on the environment in which they operate. LIDARs, for example, are ineffective in dust storms. Sonars operate differently in fresh and saline waters or in regions with hard and soft bottoms. Knowing the environment in which the sensor is operating and understanding its effects on the sensor can make significant differences in levels of performance. MCM forces need to be provided with a level of environmental prediction and sensing and an ability to optimally tune their systems, not unlike those provided to ASW forces. Adaptive sensors, which automatically sense their most effective parameters, can provide the needed in situ data. In the case of sonar, for example, the system itself can be used to measure its surrounding environment-sound speed profile, bottom backscatter, surface roughness, bubble attenuation, and so on-and automatically select an optimal operating frequency, beam pattern and signal type.

Global Positioning System

To neutralize the mine threat in minimum time, with minimum assets and effort, will require that all surface and air MCM platforms and those platforms transiting cleared channels be equipped with GPS receivers, that crews be thoroughly trained and practiced in their use, and that all charts and maps be digitized using GPS coordinates. The spatial coordination required by the MCM-amphibious assault-sea-based support element, from crisis initiation to last mine cleared, is demanding, and can be achieved only if GPS precision is available to all components. Without it, the goal of rapid conflict resolution with minimum casualties will not be attained. The panel urges the Navy and Marine Corps to equip all relevant platforms, subject their crews to extensive training, and ensure the conversion of maps and charts.

MCM Night Operations

The MCM platforms available in any future conflict could effectively be doubled simply by adding the capability to carry out night operations. The panel is aware of the principal reasons such operations have not already become standard practice. AMCM helicopters are not equipped with artificial horizons and night vision equipment, and while in tow, they fly in a dangerous part of the flight envelope. MCM surface ships are justifiably concerned about navigation in close proximity to the minefield and about the possibility of floating mines. The

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

provision of artificial horizons and night vision equipment has a straightforward fix, and systems have been recommended above for dealing with the floating mine problem. The question of night flying in tow with acceptable safety given proper equipment, the panel leaves to helicopter pilots to judge. Otherwise, the panel sees no reason why the MCM force should not adopt—even eventually prefer, all things considered—night operations. This is but another way of leveraging the force.

RECOMMENDATIONS

Mine warfare continues to be a technological challenge because of the proliferation of mines and mine technology. However, the Navy can take steps now that will provide a robust countermine capability within the horizon of this study (2035), enabling the United States to execute national policy worldwide. Recommendations arising from this study, and detailed in the report, are summarized below.

Highest-level Recommendations

Near Term
  • Implement a factory-to-seabed intelligence, surveillance, and reconnaissance capability, using a full set of ISR methods, including surveillance by satellite, atmospheric and undersea manned and unmanned vehicles, submarines, human intelligence assets, and special forces.

  • Develop technologies that will provide naval forces with organic MCM capability, including helicopter-compatible sweeping and hunting equipment, remotely operated off-board surface or UUV sensors, and on-board MCM sonars.

  • Aggressively pursue the development of so-called brute force technologies that will neutralize mines and obstacles in the very shallow water zone, the surf zone, and the craft landing zone.

Far Term
  • Develop technologies for advanced networked sensor and weapon systems consisting of the following:

    • Autonomous and semi-autonomous networked undersea systems using small, autonomous undersea vehicles, bottom-crawling variants, and fixed sensors for far-forward covert MCM; and

    • Controllable mines with remote fail-safe command and control (C2) and selective targeting.

  • Develop next-generation MCM ships as small platforms capable of sea state 4 operation, carried by a mother ship capable of battle group speeds. De-

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×

velop the lightweight hunting and sweeping technologies required for these smaller units.

  • Apply reasonable mine shock hardening and effective acoustic and magnetic signature reduction technologies to all new-construction ships.

Recommendations for Follow-on Action

  • Build an expendable mine neutralization system capable of being used, with minimal adjustment, by AMCM helicopters, by the MCM-1 and MHC-51 MCM ships, and by small MCM surface craft yet to be introduced.

  • Continue research to reveal the acoustic detection and classification methods used by dolphins. Emulate this capability to radically improve sonar sensor performance.

  • Continue to develop synthetic aperture sonar technologies to significantly improve the location and classification of mines from a safe distance.

  • Establish a research and demonstration program for rigid polyurethane foam causeway concepts.

  • Support the development of mechanical methods-ploughs, chains, and power blades.

  • Develop guinea pig ships and barges to verify clear paths to the beach.

  • Consider unmanned, precisely navigated, hardened platforms.

  • Specifically test precision bombing techniques for removal of mines in shallow water and in the surf and craft landing zones. Investigate this technique in light of newly developing higher-yield explosives.

  • Support further development of explosive MCM methods such as net and line charges.

  • Support research on pulse power technologies; this should include demonstration of concept and performance measurements.

  • Take full advantage of new modeling and simulation tools with initial focus on fleet-level applications, training, exercises, decision aids, and tactical development.

  • Reinvigorate the mine design team to provide effective offensive mining concepts and exploit threat mines.

  • Continue to develop technologies to improve environmental characterization for improved sensor performance, including through-the-sensor environmental measurement methods.

  • Provide systems and training that will allow the fleet to conduct night MCM operations.

Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
×
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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Suggested Citation:"2 Mine Warfare." National Research Council. 1997. Technology for the United States Navy and Marine Corps, 2000-2035: Becoming a 21st-Century Force: Volume 7: Undersea Warfare. Washington, DC: The National Academies Press. doi: 10.17226/5867.
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