Directed Energy 

and Fleet Defense 

Implications for 

Naval Warfare 

William J. McCarthy, Captain, USN

May 2000

Occasional Paper No. 10

Center for Strategy and Technology

Air War College

Air University

Maxwell Air Force Base
Directed Energy and Fleet Defense: 

Implications for Naval Warfare 

By

William J. McCarthy, Captain, USN

May 2000

Occasional Paper No. 10

Center for Strategy and Technology

Air War College

Air University

Maxwell Air Force Base, Alabama
Directed Energy and Fleet Defense: 

Implications for Naval Warfare 

William J. McCarthy, Captain, USN 

May 2000 

The Occasional Papers series was established by the Center for Strategy 

and Technology as a forum for research on topics that reflect long-term strategic thinking about technology and its implications for U.S. national security. Copies of No. 10 in this series are available from the Center for Strategy 

and Technology, Air War College, 325 Chennault Circle, Maxwell AFB, 

Montgomery, Alabama 36112. The fax number is (334) 953-1988; phone 

(334) 953-2985. 

Occasional Paper No. 10 

Center for Strategy and Technology 

Air War College 

Air University 

Maxwell Air Force Base, Alabama 36112 

http://www.au.af.mil/au/awc/awccsat.htm 
Contents 

Page

Disclaimer.....................................................................................................i

Author..........................................................................................................ii

Preface ........................................................................................................iii

Abstract.......................................................................................................iv

I. Introduction..............................................................................................1

II. U. S. Navy Strategic Concepts................................................................4

III. Evolving Maritime Threats....................................................................7

IV. Current State of Directed Energy Technology....................................14

V. Directed Energy and Fleet Defense ......................................................31

VI. New Concepts for Employing Naval Forces.......................................45

VII. Conclusions........................................................................................54

Notes..........................................................................................................58

i

Disclaimer 

The views expressed in this publication are those of the author and do not 

reflect the official policy or position of the Department of Defense, the United 

States Government, or of the Air War College Center for Strategy and Technology. 

i 
The Author 

William J. McCarthy, Captain, USN, is a 1976 graduate of the College of 

the Holy Cross. Designated as a Naval Flight Officer, he spent the majority of 

his career flying the E-2C Hawkeye. Operational flying tours included VAW125, VAW-121 and VAW-126. While serving as Executive Officer of VAW126, he participated in Operation Desert Shield and Operation Desert Storm, 

flying more than thirty combat missions. He assumed command of VAW-126 

in December 1991. Under his command, the Seahawks deployed on the USS 

John F. Kennedy in support of Operation Provide Promise and Adriatic operations. Following command, he served on the staff of Commander, Carrier 

Group Four. In July 1993, he was selected for Navy Nuclear Power Training. 

Upon completion of training, he reported as Prospective Executive Officer, 

John C. Stennis, in October 1995. Following the ship’s commissioning, he 

served as Executive Officer until December 1996. In January 1997, he assumed command of the Fast Combat Support Ship, USS Detroit, completing a 

successful Mediterranean and Arabian Gulf deployment and a $24 million 

dollar shipyard availability. A distinguished graduate of the U.S. Naval Test 

Pilot School, his shore duty assignments included the Naval Air Test Center 

where he served as the Project Officer for the E-2C APS-138 Radar and Update Development Programs, and he later joined the USNTPS faculty as the 

Senior Airborne Systems Instructor. Assigned to Naval Air Systems Command Headquarters, he served as the E-2C Avionics Systems Project Officer. 

He has flown over thirty different military aircraft, accumulating over 4,000 

hours and 700 arrested landings. A 1999 graduate of the Air War College, this 

research was conducted under the auspices of the Center for Strategy and 

Technology. His current assignment is the commander of the Nimitz-class 

nuclear powered aircraft carrier, the USS George Washington. 

iii 
Preface 

I am indebted to many individuals who contributed their time and knowledge to this study. In particular, I would like to acknowledge Patrick Vail of 

the Air Force Research Laboratory at the Phillips Research Site, and Joung R. 

Cook of the US Naval Research Laboratory, who provided useful information 

and insights. I also want like to express my sincerest thanks to my colleagues 

at the Center for Strategy and Technology, in particular Joe Shirey and Eileen 

Walling, who have shared my commitment to raising interest in directed energy warfare. My Air War College faculty advisors, Dr. William Martel and 

Col (Ret) Theodore Hailes, gave me invaluable encouragement and editorial 

assistance. Air War College faculty members Grant Hammond and Dan 

Hughes also provided helpful insights into modern strategic thought. Finally, 

my deepest thanks and appreciation go to my ever-patient family, my wife, 

Sharon, and our daughter Katie. That being said, I alone am responsible for 

the contents of this study. 

3i 

Abstract 

The introduction of directed energy weapons into twenty-first century naval forces has the potential to change naval tactics as fundamentally as the 

transition from sail to steam. Recent advances in directed energy technologies 

have made the development of both high-energy laser and high-power microwave weapons technically feasible. This study examines the potential adaptation of such weapons for the defense of naval forces. 

This study considers options for using directed energy systems on naval 

vessels in the context of the U.S. maritime strategy and emerging threats in 

international politics. The framework for this study is an integrated system of 

microwave devices, high-energy lasers, and surface-to-air missiles which are 

evaluated in terms of their ability to enhance anti-ship cruise missile defense, 

tactical air defense, and fast patrol boat defense. This study also examines 

collateral capabilities, such as non-lethal defensive measures and countersurveillance operations. 

The global proliferation of increasingly sophisticated weapons and the expanding demands placed on its ever-smaller navy require the United States to 

reassess its current approach to fleet operations. This study concludes that 

directed energy technology has made sufficient progress to warrant the development of sea-based weapons systems for deployment in the first two decades 

of the next century. For operational and technical reasons, a Nimitz class aircraft carrier may be the preferred platform for the initial implementation of 

directed energy weapons. If successful, the robust self-defense capability provided by directed energy weapons will permit a fundamental shift in carrier 

battle group operations from a massed, attrition oriented defense to a more 

dynamic, dispersed offense. 

iv 

Directed Energy and Fleet Defense . . .1 

I. Introduction 

Technological innovation in the latter half of the twentieth century has 

fueled a revolution in military affairs. While much has been written concerning the emergence of the information age and the role of information 

warfare, it is important to consider that less thought has been given to the 

technologies of warfare that operate at the speed of light.1

 This gap is unfortunate, as the introduction of directed energy weapons has the potential to 

change naval warfare as fundamentally as the transition from sail to steam. 

As articulated in 1997 in its Forward ... From the Sea, the United States 

Navy is committed to waging expeditionary warfare in full partnership with 

the Marine Corps. Fleet defense will need to respond to threats that may include low observable or hypersonic cruise missiles, tactical ballistic missiles 

with maneuverable re-entry vehicles, space-based surveillance systems, fast 

missile patrol boats, advanced submarines, and ultimately, weapons of mass 

destruction. To this list, it may be necessary to add airborne or space based 

lasers, as well as explosively driven directed energy weapons. 

Over the last forty years, the United States defense establishment has developed directed energy technology with a vigor that has waxed and waned 

with technological triumphs and unresolved challenges. The capability to 

use directed energy systems for the destruction of airborne targets was demonstrated over 20 years ago; yet today, the utility of directed energy systems 

continues to be debated. Born under the shadow of the inter-continental ballistic “missile gap,” directed energy weapons, and lasers in particular, were 

offered as a possible alternative to reduce the nation’s vulnerability. In the 

mid-1980’s, the Strategic Defense Initiative provided another major infusion of resources. But as the enthusiasm for “Star Wars” ebbed, military investment again declined. 

In a profound way, the Gulf War dispelled many of the doubts that surrounded the U.S. military’s embrace of technology. Predictions that sophisticated weapons and sensors would prove impractical in actual combat were 

shown to be incorrect. This sparked another renaissance in directed energy 

research. Two years ago, the U.S. Air Force study of air and space warfare 

in the twenty-first century known, as New World Vistas, devoted an entire 

volume to directed energy.

2 On the other hand, the 1997 study Technology 

for the United States Navy and Marine Corps, 2000-2035 conducted by the 

National Academy of Science, was not sanguine about the feasibility of using directed energy for defensive systems.

3 
2 . . . Directed Energy and Fleet Defense 

The pessimism expressed in some quarters may be due, in part, to the excessive optimism expressed in earlier decades, as generations of technologists promised that a revolutionary weapon was just around the corner.4

 Anticipating that lasers would be adapted at the same pace as the development 

of the airplane, both scientists and military leaders were disappointed.5

 Regardless of one’s perspective, these and other studies raise serious issues 

that merit close examination by the defense establishment. 

The purpose of this study is to examine the current state of developments 

in the field of directed energy weapons in order to assess the potential value 

of such systems for defending naval fleets, which is known as “fleet defense.” Since the military and, particularly, naval forces of the first two decades of the next century will be the product of the technologies that are produced today, it is appropriate to focus this study on the years 2020-2025. 

The timing is fortuitous because it corresponds with the predicted refuelings of the Nimitz class aircraft carriers USS John C. Stennis and USS 

Harry S. Truman. The mid-life re-fueling of a nuclear powered aircraft carrier is a multi-billion dollar investment.6 To be affordable or at least economically efficient, any major changes in naval combat systems must be 

accomplished as part of that overhaul. This is clearly a once in a lifetime 

opportunity in the fifty-year or greater service life of an aircraft carrier. One 

conclusion of this study is that the United States must identify and develop 

the critical technologies that are needed to support these changes and do to 

so as rapidly as possible. 

This study examines the Navy’s strategic concepts for the next century 

and assesses the likely threats that the United States could encounter. It then 

reviews the utility of alternative weapons, notably high-energy lasers and 

radio frequency (RF) weapons, which are the principal directed energy 

weapon concepts examined in this study. Given the significant technical 

differences, each technology is discussed separately. The feasibility of implementing one or more of these technologies in a Nimitz class carrier is 

then examined. 

The challenge facing the Navy today is similar to the predicament that it 

faced in the 1950’s when experiments showed that, while submarine 

launched cruise missiles were feasible there was no effective targeting 

scheme for employing them. The result was a thirty year delay in fielding 

the submarine launched cruise missile, which is one of the more capable 

weapons today. As noted by modern strategists, the Navy was indeed fortunate that the development of large caliber guns was not delayed until Admiral William S. Sims developed an effective fire control system.7 However, 
Directed Energy and Fleet Defense . . .3 

the counterpoint was well articulated when Bernard Brodie observed that 

“men who have been condemned out of hand as unimaginative or unprogressive may simply have been much more acutely aware of technical difficulties to overcome before a certain invention could be useful than were 

their more optimistic contemporaries.”8 

The balance of this study is devoted to assessing the implications of directed energy technologies for fleet defense and supporting the strategic 

missions of U.S. naval forces. The potential capabilities of these systems are 

examined in terms of classical and modern strategic thought, with particular 

emphasis on the challenges of employing naval power to influence nations 

whose naval forces are designed to contest rather than to control the sea. 

The implementation of a major new class of weapons has historically led 

to new concepts for naval force employment. These tactics must be developed iteratively, just as the weapons themselves. New tactics and new technology will likely lead to new issues, including the evolution of countermeasures as well as the development of entirely new concepts. A prominent 

example of the latter is whether laser systems on naval vessels could be 

used as anti-satellite weapons. 

Ultimately, the goal of this study is to establish a framework for understanding whether the U.S. Navy should pursue the near-term development 

of either or both directed energy technologies for incorporation in its aircraft 

carrier force. Given that other nations are making the investment to develop 

and field directed energy weapons, now is the time to make a commitment if 

the United States is to achieve an initial operational capability by the end of 

the first quarter of the twenty-first century.

9 For these reasons, it is imperative for naval thinkers to examine the capabilities, limitations, and military 

utility of “speed of light” weapons. As the most information-dependent 

combat force in the world, the United States has no choice but to understand 

how these emerging technologies will influence national security. 
4 . . . Directed Energy and Fleet Defense 

II. U. S. Navy Strategic Concepts 

The Navy’s strategic concept outlined in Forward ... From the Sea defines five the fundamental roles that support the U.S. national security strategy as power projection, sea control, strategic deterrence, strategic sealift, 

and forward naval presence.

10 These roles have evolved over the course of 

the twentieth century. Some, such as sea control, strategic sealift, and forward naval presence, would be familiar to Alfred Thayer Mahan and Sir 

Julian Corbett. Others, such as strategic deterrence and power projection, 

are clearly the products of the twentieth century. While each of these roles 

has vied for ascendancy, in fact, all are integral parts of both naval and national strategy. The Department of Defense’s Joint Vision 2010 describes 

the challenge of providing the nation with full spectrum dominance, that is, 

the ability to either deter or prevail in any conflict the United States might 

face, while confronted with limited budgets and a diverse array of threats 

never before seen in the nation’s history. 

Forward From the Sea (1992), which was the U.S. Navy’s first effort to 

articulate a post-Cold War strategy, built on this foundation with a shift in 

emphasis from sea control and strategic deterrence to the influence of events 

in the littoral environment that range from naval presence to full-scale combat operations. 

In the absence of a peer competitor and the shrinking forces based overseas, the United States has placed a renewed emphasis on expeditionary 

warfare. Joint doctrine defines an expeditionary force as “an armed force 

organized for accomplishment of a specific objective in a foreign country.”11 In practice, the services have refined its usage to describe standing 

integrated forces that are capable of rapid deployment to a forward area with 

organic command and control. Naval expeditionary operations are presently 

built around the structure of a Carrier Battle Group (CVBG) and an associated Amphibious Ready Group (ARG). 

The Navy Operational Concept, developed in support of Joint Vision 

2010, envisions using this expeditionary force structure to achieve “objectives across the spectrum of the National Military Strategy.”12 These would 

include peacetime engagement, deterrence and conflict prevention, crisis 

response, and ultimately fighting and winning. In meeting the challenges of 

the next century, Joint Vision 2010 states that “power projection, enabled by 

overseas presence, will likely remain the fundamental strategic concept of 

our future force.”13 Aside from a retaliatory nuclear strike launched from the 
Directed Energy and Fleet Defense . . .5 

ballistic missile submarine force, the ultimate projection of naval power and 

influence is exercised with the insertion of Marine Expeditionary Forces 

(MEF). If a confrontation moves toward a major theater war, on-scene 

forces, such as a CVBG-ARG team and an Air and Space Expeditionary 

Task Force (ASETF), will likely play a critical role in halting or at least disrupting an aggressor’s military plans. By precluding a quick victory, expeditionary forces buy the time needed to forge coalitions and assemble 

forces. The Navy and the Marine Corps have identified the five principal 

elements that are essential to the success in expeditionary warfare as maritime dominance, maneuver dominance, air dominance, firepower, and information superiority.

14 

To meet this challenge, the services envision taking a quantum step forward from the concepts of amphibious warfare employed over the last one 

hundred years to the new operational concept of Operational Maneuver 

From The Sea (OMFTS).15 The Marine Corps plans to use technology to 

field platforms, such as the tilt-rotor MV-22 Osprey, to permit “ship to objective maneuver” and true “over the horizon assault.” Freed from the constraints of conducting assaults over the beach, the amphibious force will operate in a battle space whose area has increased by two orders of magnitude, 

from 30-50 square miles to 2500-3000 square miles.16 

Projecting combat forces ashore is one of the most challenging tasks that 

naval forces face. Maritime dominance is critical, in part because littoral 

warfare brings the naval force closer to the contested landmass. This is not a 

new challenge, and in fact, the most important naval battles have been 

fought close to shore, even though the majority of wars have been decided 

on land. However, as naval forces approach the adversary’s coast, the defender typically gains the advantage of employing less expensive weapons 

systems to repel the attacker. Mines, small patrol craft, coastal submarines, 

land-based aviation, and shore-based missiles may all be brought to bear. 

Conceptually, Operational Maneuver From The Sea allows the ground 

force commander to maximize the ability to employ maneuver warfare for 

striking the foe where least expected. For naval forces, the ability to remain 

a significant distance offshore increases the freedom of movement and 

complicates the enemy’s calculations. However, once troops are placed 

ashore, the supporting naval forces become clearly tied to that operational 

area. While the concepts proposed in Operational Maneuver From The Sea 

increase the area of the “battlespace” by several orders of magnitude, it also 

has the corollary effect of requiring far greater reliance on sea-based logistics and naval fires. 
6 . . . Directed Energy and Fleet Defense 

The nature of the force and the capabilities of individual units define, as 

well as constrain, the strategy that a navy can undertake. Modernization can 

change a navy’s ability to execute its missions in unanticipated ways, as exemplified by the challenge faced by the Royal Navy with the transition from 

sail to steam at the end of the nineteenth century. The United States Navy is 

in the throes of change today. In the case of the surface force, the development of AEGIS guided missile destroyers has produced a smaller number of 

vastly more capable escorts. Fully equipped to provide area air defense, 

these ships may ultimately be integrated into the fleet’s theater missile defense architecture. However, one consequence of this mission has been to 

reduce the number of ships available to serve as escorts for high-value units, 

such as aircraft carriers, amphibious units, and merchant shipping. This 

trend is likely to continue as the Navy replaces 31 destroyers and 51 frigates 

with 32 of the new DD-21 “Land Attack” destroyers.17 

As long as the United States remains the preeminent maritime nation, 

seapower will be critical to the success of its security. While the strategic 

emphasis may shift with the ebb and flow of competitors, the pillars of the 

U.S. Navy’s maritime strategy will remain the forward presence, strategic 

sealift, and sea control that, together, remain inextricably tied to the projection of power in expeditionary warfare. 
Directed Energy and Fleet Defense . . .7 

III. Evolving Maritime Threats 

Maritime forces in the twenty-first century will confront a formidable 

array of threats. Even without the emergence of a significant competitor, 

the U.S. and allied navies will face unprecedented challenges from the 

proliferation of sophisticated missile and sensor technology. The explosion 

of computer technology has created a situation in which the most sophisticated weapons systems, with advanced fault-tolerant architectures, may 

present opportunities for less technologically advanced states. Rather than 

confronting the U.S. Navy directly with expensive, advanced technology 

ships and aircraft, a more prudent course for adversaries is to seek asymmetric advantages through the use of chemical weapons, missile technology, and other emerging technologies, all of which represent relatively 

inexpensive countermeasures to U.S. naval forces. The discussion in this 

section focuses on the threats to U.S. naval forces that technology has created. 

Cruise Missiles. While mines, torpedoes, and ballistic missiles all pose 

significant threats to naval forces, the greatest single area of concern is 

probably the cruise missile.

18 It is currently estimated that roughly 70-75 

countries possess cruise missiles, and of these, nineteen have produced their 

own missiles or have manufactured cruise missiles under license agreements.

19 The trend towards proliferation is likely to continue, as both purchasers and producers demonstrate the ability to “reverse engineer” designs 

from operational missiles. China has led the way with its successful production and export of the C-801 and C-802 anti-ship cruise missiles that were 

developed from the Exocet missile. The Indian Koral program is allegedly 

developing an indigenous version of the former Soviet SS-N-22 Sunburn 

supersonic anti-ship cruise missile. Given China’s record of reproducing 

foreign designs, Russia’s decision to export the SS-N-22 with the sale of 

Sovremennyy Class destroyers could lead to a new round of competition 

between India and China for dominance of the supersonic anti-ship cruise 

missile market. 

The proliferation of cruise missile technology is not limited to the major 

powers. The Taiwanese Hsiung Feng II was reverse engineered from the 

Harpoon, while Iran and Iraq both developed longer range variants of the 

Chinese HY-2 Silkworm (originally developed from the Soviet SS-N-2 

Styx). The evidence is that nations which have the capability of producing 
8 . . . Directed Energy and Fleet Defense 

jet aircraft generally also have the ability of producing cruise missiles, and 

most have demonstrated that they have an interest in doing so.20 

The two major trends in cruise missile development have been increased 

speed and reduced radar signature, the latter of which is known as “stealth.” 

Early cruise missiles, such as the Tomahawk and Kingfish, were designed 

with turbofan engines for long range or rocket motors for high speed, respectively. Recent advances have brought a new generation of ramjet engines, such as the French ASMP and ASURA, which are capable of speeds in 

excess of Mach 2. Exocet and other solid fueled rockets are replacing the 

Styx and other liquid fueled models. The use of solid fuel motors simplifies 

operations, maintenance, and logistic support, and thus makes the weapon 

system more attractive to the less technologically sophisticated customers. 

The Italian TESEO-3 typifies advances in reducing the radar signature 

through shaping the missile and coating it to produce subsonic missiles that 

are extremely difficult to detect. As these trends continue, it is likely that 

technology will make increasingly sophisticated missiles available at prices 

that many states can afford.21 

Remarkably flexible in application, cruise missiles have been adapted 

from anti-ship to land-attack missions and from ship-launched to airlaunched operations with little difficulty. While only three nations (France, 

Russia, and the United States) are known to have developed cruise missiles 

that can deliver nuclear weapons, the potential exists to use cruise missiles 

for dispensing chemical and biological warfare agents.

22 There are public 

reports that China, Iran, and Syria are attempting to develop this capability.

23 Closely related to the proliferation of cruise missiles is the development of remotely piloted vehicles (RPVs). The Indian Lakshya, the Iranian 

Baz, and the Israeli Delilah all represent the class of so-called “harassment 

drones” that have the ability to deliver ordnance. Remotely piloted vehicles 

have the capability of locating and targeting naval forces operating in the 

littoral, and as with cruise missiles, the flight profiles of RPVs lend themselves to the dispersal of chemical or biological (CW/BW) agents.

24 

In summary, a nation that wants to challenge a major naval power for local control of the sea will probably turn to cruise missiles because these offer a relatively economical method for conducting a sophisticated attack 

with a reasonable probability of inflicting some damage. 

Theater Ballistic Missiles. While the proliferation of theater ballistic 

missiles has captured considerable public attention since Iraq employed the 

Scud B missiles during the Gulf War, it represents a lesser threat to naval 
Directed Energy and Fleet Defense . . .9 

forces than cruise missiles. There are presently about forty nations that have 

fielded or produced ballistic missiles, and eleven of these nations can produce nuclear, chemical or biological weapons. 

However, there are technological challenges that must be addressed in 

order to equip a ballistic missile with a CW/BW warhead.25 Since the most 

commonly deployed ballistic missiles are the Scud missiles or Scud derivatives, which are accurate within 1 kilometer, the probability of damaging a 

ship at sea with a conventionally equipped missile is small. Nevertheless, in 

certain naval operations, such as traditional amphibious landings, the resulting concentration of ships would be vulnerable to ballistic missiles that 

are armed with weapons of mass destruction. The trend in ballistic missile 

development is toward greater sophistication with improved mid-course 

guidance systems, such as Global Positioning System, and more accurate 

algorithms for calculating re-entry ballistics. The replacement of unitary 

warheads with sub-munitions is another low-cost option for improving lethality. In the near-term one can foresee accuracy improvements on the 

scale of two orders of magnitude. While their maritime role is limited, 

theater ballistic missile tests can be used to influence neighboring, as exemplified by the missile tests conducted by China that intimidated Taiwan in 

June 1996.26 

Nuclear, Chemical and Biological Warfare. Frequently grouped under 

the generic heading of weapons of mass destruction, these weapons represent a significant concern for naval forces because naval warfare is a nearly 

ideal medium in which to employ weapons without inflicting high levels of 

collateral damage. Even during the Cold War, naval strategists discussed the 

possibility of whether nuclear torpedoes and depth bombs could be employed without necessarily escalating a crisis to a general nuclear war. 

While nuclear proliferation remains a serious concern in light of recent developments in India and Pakistan, the proliferation of chemical weapons is 

an even greater concern. If employed against naval units, chemical weapons 

could significantly hamper military operations even if the attack does not 

produce significant casualties. 

The Soviet Union possessed a chemical arsenal that is estimated to have 

exceeded 50,000 tons of agents that ranged from phosgene, which was used 

during the First World War, to sophisticated nerve agents, including sarin 

and soman. Equally important, the vast majority of Soviet weapon systems 

were configured for use with either conventional or chemical warheads. The 

implication is that much of the military hardware in the Third World is 
10 . . . Directed Energy and Fleet Defense 

readily adaptable to chemical weapons. Chile, Egypt, Iran, Iraq, Israel, 

Libya, North Korea and Syria all reportedly have developed chemical 

weapons, and Pakistan is reportedly engaged in a significant chemical 

weapons program. For other nations or non-state actors, it is arguably possible to hire former weapons technologists or purchase the precursor chemicals on the open market.

27 Attempts to control proliferation have been seriously hampered by the fact that because many of the precursor chemicals 

have legitimate dual uses, a complete ban on the exportation of all possible 

pre-cursors is not practical. For example, when confronted with an embargo 

on the pre-cursor chemical needed to manufacture soman, Iraq allegedly 

shifted to the manufacture of sarin instead.28 

Finally, the repeated use of CW in the Iran-Iraq War and the SovietAfghanistan War probably lowered the threshold for its employment in future conflicts. 

Mines and Torpedoes. After cruise missiles, these weapons pose the 

greatest threat to naval forces conducting expeditionary warfare. The U.S. 

Office of Naval Intelligence estimated that there are over 150 types of naval 

mines in the service of at least 50 nations. These range from the simple 

World War I vintage contact mines that proved effective in the Arabian 

Gulf, to highly sophisticated propelled warhead mines, which can defend an 

area up to one half square mile. Even with greatly enhanced lethality, mines 

are expected to remain primarily a threat in shallow waters (less than 200 

fathoms), and thus could pose an insurmountable obstacle to classic amphibious warfare.29 By re-shaping the traditional doctrine of amphibious 

warfare, Operational Maneuver From The Sea seeks to reduce this vulnerability. 

For an opponent seeking an asymmetric advantage, torpedoes, like 

mines, are relatively inexpensive weapons that can destroy high-value targets. The proliferation of sophisticated torpedoes has continued as France, 

Germany, Italy, and Russia are actively exporting wake-homing torpedoes. 

Germany has offered kits for retrofitting previous models that were sold 

with Type 209 diesel electric submarines, which in a littoral environment is 

a formidable weapon given its inherently quiet nature. However, the popularity of the submarine as the weapon of choice among Third World states 

may be waning, as states that purchase these weapons face the burden of 

maintaining complex systems. Effective submarine employment requires a 

cadre of skilled technicians and tacticians, all of whom need to maintain a 

high level of proficiency. While the threat will likely grow from those na-
Directed Energy and Fleet Defense . . .11 

tions willing to make the commitment of fiscal and personnel resources, in 

other cases, submarines will become expensive showpieces that have little 

combat capability.

30 Nevertheless, the United States is well advised to focus 

on the risk posed by the proliferation of torpedo technology. 

Low-Observable Ships and Aircraft. The deployment of a significant 

number of surface combatants that employ “stealth” technology will increase in the twenty-first century. In addition to the United States, a number 

of states, including Sweden, Spain, Israel, Canada, Great Britain, Russia, 

France, and Saudi Arabia, are developing or fielding low-observable ships. 

Computer aided design systems have made this technology readily accessible to any ship builder, and radar absorption materials are now commercially marketed by several nations. While none of these approaches create 

“invisible” ships, the fact that it is much more difficult to locate and target 

these ships effectively enhances the effect of decoys or other countermeasures. 

While true “stealth” aircraft may remain beyond the financial reach of 

most nations, the basic principles of radar signature management are likely 

to be applied in the design of future tactical aircraft. These measures will 

complicate the early detection and tracking of aircraft, particularly in the 

littoral environment. As previously discussed, the most significant advances 

are more likely to occur in the growing sophistication of anti-ship missiles 

than in the platform from which the missile is launched.31 

Information Warfare. The information explosion has the potential to profoundly alter the conduct of war. Much has been written regarding the opportunities as well as the vulnerabilities of a globally connected information 

grid. Satellite imagery and communications, long the province of the major 

powers, are increasingly available in the world marketplace.32 Commercial 

systems now routinely provide encryption and resolution capabilities that 

until a few years ago existed in the purely military domain. For the maritime 

commander, the growth of communication systems offers an unparalleled 

degree of connectivity and access to national resources. However, a totally 

new series of threats appear to be emerging, which involve weapons that are 

designed to destroy high-technology communication, sensor, and computer 

systems. 

During testimony in February 1998, before the Joint Economic Committee of the U.S. Congress, an official from the U.S. Army’s Space and 

Missile Defense Command stated that recent scientific advances in radio 
12 . . . Directed Energy and Fleet Defense 

frequency (RF) weapons technology by several states raise significant concerns. Broadly speaking, these weapons use high power microwave energy, 

in either narrow or wideband form, to disrupt or destroy the high-density 

metal oxide semiconductor devices that are used in modern computers and 

sensors. The Soviet Union long dominated the research in this field. In 

1994, the Director of the Central Institute of Physics and Technology in 

Moscow distributed a series of papers by A. B. Prishchepenko, the inventor 

of compact, explosively-driven RF munitions, which described how such 

munitions could be employed against land mines, sea-skimming missiles, 

and communication systems. There is evidence that the Ukrainian, Swedish, 

French and Australian governments are actively investigating RF weapons 

technology.

33 Testimony before the same committee highlighted how simple 

it is to construct so-called transient electromagnetic devices. A pre-eminent 

example was a homemade device fabricated for under $5,000.34 And it 

should be noted that the Internet has become a significant factor in the 

worldwide dissemination of RF weapon technology. 

The development of RF weapons has profound consequences for the 

United States. As the most technologically sophisticated nation, the United 

States is vulnerable to an attack that strikes directly at the heart of its information systems. In military terms, warships bristling with communication 

and sensor antennae are prime targets for an attack with RF weapons. Conceptually, these weapons may offer an enemy an inexpensive and highly 

effective system for suppressing defenses, which would render the victim 

virtually defenseless against an attack with conventional guns, bombs, or 

missiles.

35 

The other directed energy weapon that is maturing is the laser. Since 

the Vietnam War, lasers have been used extensively in weapon guidance. 

In the late 1990s, a number of states, including France, Britain, Russia, 

Germany, and Israel are reportedly pursuing lasers as weapons. The Royal 

Navy may have fielded a shipboard system known as “Outfit DEC” as 

early as the Falklands War.36 The current market leader in anti-personnel 

and anti-sensor laser weapons is China.

37 Over the next 15 years, the Office of Naval Intelligence predicts the development of high-energy lasers 

that are capable of damaging electro-optic sensors at long ranges.38 Other 

sources indicate China may have already developed a limited anti-satellite 

laser capability.

39 

Summary. In addition to directed energy research programs, China, Russia, France, and Germany all have made significant investments in aero-
Directed Energy and Fleet Defense . . .13 

space technology. With the development and proliferation of systems that 

are capable of attacking a force built on information superiority, the United 

States must consider how twenty-first century enemies might use sophisticated, low-cost weapons to gain an asymmetric advantage in the contest for 

local control of the sea.40 Such an opponent will not seek to win a battle 

with a major naval power, but rather to make the cost of its defeat prohibitive. 
14 . . . Directed Energy and Fleet Defense 

IV. Current State of Directed Energy Technology 

Fascination with directed energy weapons has pre-saged the development of that technology by several generations. Indeed, some have drawn 

the line back to the legend that Hippocrates’ defended Syracuse by using 

Archimedes’ idea of reflecting sunlight to destroy the Roman fleet. Others 

have traced its roots to science fiction writers, such as Jules Verne and H.G. 

Wells. In 1938, Generals “Hap” Arnold and Ira Eaker wrote that defense 

against aerial attack was practically impossible until science developed new 

inventions such as “an electric ray which has been given credit for being 

able to stop gasoline engines by putting out of commission their electrical 

system.”

41 Less than ten years later, U.S. Navy scientists proposed using 

directed energy in the form of radio waves to defeat atomic weapons before 

they could reach their targets.42 

While the theoretical birth of the laser is ascribed to Albert Einstein’s 

prediction of “stimulated emission,” in practical terms the laser was the 

outgrowth of the work of Arthur L. Schawlow and Charles H. Townes on 

an optical Microwave Amplification by Stimulated Emission of Radiation 

(MASER). Others pioneering in the field included the Soviet scientists, 

Aleksander M. Prokhorov and Nikolai Basov, as well as a Columbia University graduate student, Gordon Gould, who independently reached the 

same conclusions and, in fact, coined the term laser. The Hughes Corporation physicist Theodore H. Maiman in May 1960 demonstrated the first 

ruby laser. Replacing the term optical MASER, lasers entered the vernacular as an acronym for Light Amplification by Stimulated Emission of 

Radiation. While sharing common roots in the MASER, laser and high 

power microwave research diverged rapidly over the succeeding decades. 

Confronted with the nuclear arms race, the Department of Defense 

looked eagerly at laser technology as a means to counter the seemingly 

unstoppable threat posed by inter-continental ballistic missiles. The Advanced Research Projects Agency became an early sponsor of Gould’s 

proposal to build a laser.43 In 1958, the DOD inaugurated a research and 

development program, known as Project Defender, to search for viable 

anti-ballistic missile technologies. Under the charter of Project Defender, 

the Office of Naval Research managed Project Seaside, which sought to 

determine whether a ruby laser could be used as an anti-ballistic missile 

system. Given its expertise in nuclear warheads, the Air Force was commissioned to study the energy necessary for a laser to destroy an ICBM. 
Directed Energy and Fleet Defense . . .15 

This 1962 study marked the genesis of the team that was to develop the 

Airborne Laser Laboratory and, ultimately, the Airborne Laser.44 

Laser Technologies 

Of all the approaches to using directed energy, lasers are probably the 

most familiar. Broadly speaking, laser technology has matured rapidly over 

the last thirty-five years. From the beginning, commercial research has been 

as important as that sponsored by the military. The widespread use of compact, inexpensive, low-power lasers attests to the growth of the technology. 

The commercial and military applications of so-called low energy lasers, 

which range from CD players to laser guided bombs, are well known. While 

not as rapid as some proponents had hoped, there has been significant progress in military applications. 

Regardless of application, lasers are generally categorized by the substance being lazed (gas, liquid, or solid) and the method of stimulation or 

“pumping” (pulse discharge, electricity, or chemical reaction) used. The 

product is a beam of coherent light at a given wavelength.45 The third component of most laser systems is a resonant optical cavity, which provides the 

means for increasing the energy in the beam and extracting that energy. In 

its simplest form, a resonator can be a pair of optical mirrors, one of which 

is only partially reflective. As the beam traverses back and forth through the 

lazed media, the photons in the beam stimulate further emissions. In actual 

practice, there are a variety of resonator designs as well as systems that employ other methods of amplification.46 

The reason that lasers have important military applications is related to 

the unique characteristics of the beam. Unlike ordinary incandescent lights 

that scatter energy in a random fashion, the beam produced by a laser can be 

highly collimated. Consequently, the energy deposited on an area of one 

square centimeter by a 100 watt laser may be as much as nine orders of 

magnitude, that is, one billion times greater than the energy deposited by a 

100 watt incandescent lamp.47 

While it is common to describe lasers as monochromatic, i.e., consisting 

of a single color or wavelength, this is somewhat inaccurate. For a wide variety of reasons, lasers normally operate across a relatively narrow band of 

wavelengths at which significant amounts of energy are radiated.48 However, the outputs of certain types of lasers can be adjusted. For example, the 

output of typical chemical dye lasers may be tuned from the near-ultraviolet 
16 . . . Directed Energy and Fleet Defense 

to the near infrared. Free electron lasers are also theoretically capable of 

tuning across wide bands. Other methods of adjusting wavelengths include 

optical techniques and Raman shifting. As one might expect, all of these 

approaches involve significant penalties in complexity, which translate directly into increased cost and decreased reliability.

49 

The type of material employed in the optical cavity may categorize a laser. There are four major types that appear to have applications for directed 

energy weapons. Solid state lasers use a non-conductive glass or crystalline 

material that is doped with a species, such as, neodymium or erbium, as the 

active medium. The prime example would be the original ruby laser. 

Chemical lasers use the reactions of gases or liquids to create the excited 

energy states necessary for laser emission. Semi-conductor (or diode) lasers 

use the current flow through an electrical junction to excite the electrons. At 

low current densities, the device functions as a light emitting diode. However, if the system is designed with optical feedback, the current density can 

be increased to a sufficient level that the diode will operate as a laser.50 The 

most common application of this type of laser is found in compact disc 

players. The fourth category is the ubitron or free electron laser. This device, which more closely resembles a high voltage linear accelerator, is capable of producing high power radiation across a broad band of frequencies. 

Diode Pumped Solid State Lasers. During the 1960’s and seventies, solid 

state lasers enjoyed considerable popularity in military applications, such as 

range-finders. There has been a renewed interest in the possible weapons 

applications of solid state lasers following significant technical advances 

that have occurred during the last five to seven years. In 1995, a DARPAArmy sponsored, diode pumped laser, developed by TRW, demonstrated a 

power output of 250 watts with a 100 Hz repetition rate. In spite of this progress, advances in three major areas will be necessary for solid state lasers 

to become viable candidates for high power military applications. The first 

is the diode cost, typically $10-$20 per watt peak power, which makes them 

impractical for applications requiring 10 kW or higher. The second is the 

relatively low net efficiency, on the order of 9-15 percent. And the third is 

the intolerance of high temperatures, which complicates the transfer of 

waste heat. The need to dissipate large amounts of heat imposes mass flow 

requirements that are analogous to those encountered with gas combustion 

lasers. Thus, for military high power applications, the inherent size advantage of the solid state laser is offset by the need for a system that can handle 

large volumes of cooling medium.51 
Directed Energy and Fleet Defense . . .17 

Recent advances with indium gallium arsenide diode arrays and ytterbium doped laser crystals offer significant improvements in waste heat reduction and increased pumping efficiency. Another concept is to treat the 

thermal capacity of the laser as a “magazine” that defines the total energy 

output of the weapon over the firing cycle. The weapon is reloaded by 

cooling the laser. Assuming a yield of 500-1000 joules per cm3

 of host material, approximately 10-15 kg would be required for each megajoule of 

magazine capacity. The Air Force estimates that the minimum energy 

needed to destroy small tactical missiles will be less than 100 kilojoules.52 

This approach has the advantage of a “magazine” that only requires cooling 

to “reload.” This frees the firing platform from the need to return to a fuel or 

ordnance depot to re-arm. 

The potential for a compact system that uses environmental cooling 

makes the diode pumped solid state laser an attractive candidate for use on 

tactical aircraft. While the path to the development of such weapons appears 

straightforward, there are still significant challenges to be overcome. Reasonable estimates put the availability of this technology between 2015 and 

2020.53 

High Power Semi-conductor Lasers. Building on the commercial success 

of the early 1980’s, the high power semiconductor laser technology 

(HPSLT) program at Phillips Laboratory has achieved an increase in output 

power of two orders of magnitude since 1984. Semiconductor lasers offer 

the greatest efficiency (by a factor of at least four) when compared with 

other laser designs. Compact, solid state, and based on microelectronics, 

they offer superior reliability at minimum cost. Initial demonstrations indicate that semiconductor lasers can be employed in phased arrays that will be 

scalable to high power applications. 

The Air Force’s “Foto-Fighter” concept relies heavily on the use of embedded arrays of semi-conductor lasers as sensors and weapons. The emphasis in the high-power semiconductor laser technology program has been 

to improve the power output of each element, to develop alternate frequencies, and to design coherent arrays. While most of the research to date has 

been done with aluminum gallium arsenide and indium gallium arsenide, 

other materials, such as antimony, offer the promise of broader bandwidths. 

The stated goal is to incorporate devices that produce good beam qualities 

for both offensive and defensive applications. 

A related development is the use of a semiconductor laser to pump a single fiber laser that uses a rare earth dopant as its fiber core. By expanding 
18 . . . Directed Energy and Fleet Defense 

upon the work done to produce a 1000 element linear semiconductor array, 

a 10,000-beam fiber optic laser weapon may be feasible. For aircraft applications, the improvements in aircraft performance and reliability gained by 

eliminating high-drag turrets and mechanically complex tracking systems 

are obvious. Equally appealing is the possibility of fielding a more robust 

and responsive weapon that is scanned electronically. 

Chemical Lasers. The greatest successes in high power lasers attained to 

date have been in the field of chemical lasers. The three that appear to offer 

the greatest potential are the hydrogen fluoride laser, the deuterium fluoride 

laser, and the carbon dioxide iodine laser. The hydrogen fluoride and deuterium fluoride lasers, which were initially developed by the United Technologies Research Center in the late 1960’s, operate on the same basic principles.

54 The hydrogen fluoride laser produces wavelengths between 2.7 and 

3.3 microns, in the infrared region where atmospheric absorption is strong. 

Because of its heavier atomic mass, the hydrogen isotope deuterium produces a longer wavelength emission. Deuterium fluoride lasers emit in the 

3.5-4.2 micron region where the atmosphere is more transparent. 

The differences in absorption characteristics led initially to two different 

sponsors. With its shorter wavelength and therefore smaller optics, the hydrogen fluoride laser is considered a leading contender for the Ballistic Missile Defense Organization’s Space-Based Laser program. On the other hand, 

the deuterium fluoride laser is the basis for TRW’s Mid-Infrared Advanced 

Chemical Laser (MIRACL). While originally developed in the 1970’s for 

the U.S. Navy, the latter is now serving as the basis for the Nautilus Tactical 

High-Energy Laser (THEL) demonstrator that is being co-developed with 

the Israeli Ministry of Defense.55 

The MIRACL is the only operational megawatt class laser in the United 

States. Employed with the Sea-Lite Beam Director system, it has completed 

a number of successful demonstrations, including the shootdown of five 

sub-sonic BQM-34 drones in 1987 and the successful engagement of a supersonic Vandal missile target in 1989.56 In February 1996, the U.S. Army 

used the MIRACL/Sea-Lite Beam Director to successfully destroy a shortrange Brant rocket in flight. In 1997, the MIRACL/Sea-Lite combination 

demonstrated the ability to illuminate satellites on orbit.57 In spite of these 

successes and the contractor’s proposal for an engineering model demonstration at-sea, the Navy determined that the deuterium fluoride wavelength 

was unsuitable. It subsequently loaned the equipment to the U.S. Army for 

the latter’s THEL program.58 
Directed Energy and Fleet Defense . . .19 

The U.S. Air Force pursued the alternative approach of developing the 

Chemical Oxygen Iodine Laser (COIL) from its Ground Based Laser Technology program.59 Because of its shorter wavelength, the optical systems 

associated with the COIL are substantially smaller than those in either the 

hydrogen fluoride or deuterium fluoride lasers. As with the deuterium fluoride laser, the COIL is subject to significantly less water vapor absorption 

than the hydrogen fluoride laser. Given these characteristics, the decision 

was made to develop a multi-module megawatt class COIL for the Airborne 

Laser (ABL).60 The ABL builds on the success of the Air Force’s Airborne 

Laser Laboratory, which demonstrated that missiles could be successfully 

engaged and destroyed by a laser mounted in a NKC-135 aircraft.

61 

Free Electron Laser The ubitron, also known as the free electron laser, is 

the product of extensive work by the Strategic Defense Initiative Organization.62 While the initial intent was to develop a free electron laser as a 

weapon, current research suggests that it may be most useful as a device to 

produce high-power microwaves.

63 The Navy is continuing to support modest research in FEL technology for the possible development of a shortrange anti-ship missile defense system.64 

Laser Optics. Optical systems provide the path needed to focus and direct a laser beam so that the energy can be usefully employed. High-energy 

lasers pose particular challenges for optical designers because the devices 

must be able to withstand the deposition of substantial amounts of energy. 

As the Airborne Laser Laboratory demonstrated, the optical path from the 

laser to the aperture is critical. Aberrations in the HEL’s gain medium, imperfections in laser optical surfaces, atmospheric and vehicle turbulence, 

and imperfections in the beam director all require compensation if sufficient 

energy is to be deposited on the surface of the target. 

In view of the tremendous ranges involved in ballistic missile defense, 

the Air Force has focused considerable research on atmospheric turbulence 

and methods of compensation. The result has been a series of breakthroughs 

that demonstrated the feasibility of using adaptive optics to compensate for 

atmospheric turbulence as well as distortions induced within the device’s 

internal optical path. The Air Force Research Laboratory’s Phillips Research Site has successfully demonstrated the use of a deformable mirror 

system to effectively pre-distort laser beams. The adaptive optical system 

employs hundreds of small actuators that deform the surface of the mirror in 

response to atmospheric scatter sampling data to eliminate, or “null out,” 
20 . . . Directed Energy and Fleet Defense 

atmospheric distortion. The Air Force is continuing to examine potentially 

less complex alternatives.

65 While critical to the success of certain highenergy laser applications, earlier experiments demonstrated that these technologies are not essential for lasers employed at tactical ranges of less than 

20 kilometers.

66 

Tracking and Fire Control Systems. To achieve the most rapid destruction of the target, a laser weapon must deposit the maximum amount of energy on the smallest possible area of the surface of the target. This constraint puts high demands on the tracking and fire control systems associated with a laser weapon.67 One advantage of laser weapons is the incredible 

speed differential between lasers that operate at the equivalent of Mach 

1,000,000 and missiles at speeds of Mach 2-3. Even a hypersonic missile 

will move only a comparatively short distance during the time it takes for a 

laser to engage it. The ultimate successes of the Airborne Laser Laboratory, 

the Sea Lite Beam Director, and the Nautilus program all demonstrate that 

the basic technology for laser tracking and fire control systems is available. 

While the Sea Lite Beam Director was deemed to be too large for shipboard 

installation, its developer was confident ten years ago that a downscaled engineering development model was feasible.

68 

Laser Limitations 

While size, weight, volume, power, and cooling requirements dominate 

discussions of airborne and space-based laser applications, the greatest 

challenges for terrestrial or sea-based system originate from atmospheric 

effects. The effects of turbulence have been discussed and, as noted, atmospheric turbulence is a limiting factor for strategic applications, such as the 

using the Space-Based Laser or the Airborne Laser for missile defense. For 

tactical applications, atmospheric turbulence is just one environmental factor to be considered along with absorption, scatter, and thermal blooming. 

Absorption. In simplest terms, only photons at specific wavelengths are 

absorbed because the energy levels that exist in a given molecule are present 

in discrete states. Therefore, only a single spectral line is absorbed for each 

excited state. In practice, a broadening of spectral lines results in a series of 

so-called “window regions” or ranges of wavelengths in which absorption is 

relatively weak.69 In the infrared region, water and carbon dioxide molecular absorption defines the window regions. At millimeter and microwave 
Directed Energy and Fleet Defense . . .21 

wavelengths, absorption by diatomic oxygen and water molecules is the 

predominant factor. The characteristic windows used for military applications have traditionally been the 8-12 micron and 3-5 micron windows. The 

COIL exploits the window at 1.3 microns.70 

Absorption and refraction significantly influence the use of lasers for terrestrial and maritime applications. The lower portion of the atmosphere, the 

troposphere, extends to a nominal altitude of 11 kilometers, or approximately 36,000 feet. Most of the principal atmospheric attenuators, including 

water and carbon dioxide molecules, clouds, fog and other aerosols, are 

found in this region. While the amount of water vapor present is highly dependent upon seasonal and weather variations, it is the predominant factor 

in the maritime environment. In addition to absorption by individual water 

molecules, water vapor also influences particle scattering.

71 The effect of 

these variations is to make atmospheric predictions difficult. 

Scattering. For the purpose of this discussion, atmospheric particles can 

be divided into two groups, aerosols and hydrometers. The first group has 

an average radius of less than one micron. Scattering by aerosols is significantly greater than the molecular scattering described above.72 On the other 

hand, hydrometers or water bearing particles tend to be substantially larger 

than one micron. Given their larger size, they do not remain suspended, but 

instead are removed by coagulation, fallout, or washout. Again, the widely 

varying sources and methods of distribution make it difficult to predict how 

the propagation device for a laser will perform on any given day. In addition 

to these natural challenges, there are also military obscurants that have median particle diameters ranging from 0.6 to 3.4 microns.73 

Thermal Blooming. As a high-energy laser beam propagates through the 

air, small amounts of energy are transferred to the molecules along its path. 

The heated air expands and effectively creates a lens, which distorts the laser beam. This spreading effect is generally referred to as thermal blooming. 

While an annoyance for low power laser applications, such as illuminating a 

target for destruction with a conventional weapon, blooming can become a 

limiting factor in the efficiency of high-power lasers. While wind and beam 

motion are significant factors in determining the magnitude of the effect, 

thermal blooming poses the greatest single challenge for laser applications 

in the troposphere.74 

Summary. Laser technology has matured greatly over the last forty years. 

While the development of higher power and more efficient devices continue 
22 . . . Directed Energy and Fleet Defense 

to progress, the significant fact is that lasers have the demonstrated ability to 

destroy missiles. Terrestrial and maritime lasers capable of delivering sufficient power for weapons applications appear to be feasible without major 

technological innovations. The limitations imposed by tropospheric propagation phenomena are still undetermined, but it must be understood that this 

could ultimately compromise the effectiveness of laser-based systems for air 

defense. 

Radio Frequency Weapons Technologies 

The second major category of directed energy weapons are the Radio 

Frequency (RF) devices. Rather than operating in the infrared, visual, or 

ultra-violet spectra, these devices operate in the communications, navigation, and radar frequency bands from approximately 100 MHz to 10 GHz. 

Radio frequency devices are typically sub-categorized as either High Power 

Microwave (HPM) or Ultra-Wideband (UWB) systems.* 

Origins. With their origin in the radio and radar devices developed in the 

first half of the twentieth century, microwave devices pre-dated the development of lasers. Indeed, World War II had proven the value of microwave 

technology for communications and sensors. The 1970’s saw the commercialization of microwave technology as the microwave oven became a 

household fixture. While much of the radar and communications research in 

the military focused on signal processing in a never ending drive to extract 

ever smaller signals from an increasingly noisy environment, significant 

progress was made in the development of new transmission systems. New 

solid state transmitters were developed and electronically scanned phased 

arrays began to replace simple mechanically scanned antennas in many applications. 

There were separate efforts to examine the effects of the electromagnetic 

pulse associated with the detonation of nuclear weapons. While the 1957 

edition of The Effects of Nuclear Weapons did not directly address electromagnetic pulse phenomena, the latter were included in the 1964 revision 

* High-power microwave devices typically operate at frequencies between 1-20 GHz with large 

pulse widths (on the order of one microsecond) and relatively narrow bandwidths (nominally 

one percent of the frequency, which equates to approximately 10 MHz at the lower end and as 

much as 100 MHz at the upper end). Ultra-wideband systems are characterized by narrow pulse 

widths of less than 100 nanoseconds and bandwidths that may exceed 50 percent of the center 

frequency. Typical wideband devices have bandwidths that range from 200 MHz to 3 GHz. 
Directed Energy and Fleet Defense . . .23 

and filled an entire chapter in the 1977 edition.75 Scientists learned that 

EMP was a likely cause of the electronic equipment malfunctions that were 

encountered during atmospheric testing. One publicized example was the 

large-scale failure of streetlights on the island of Oahu, which was caused 

by a high-altitude detonation 500 miles away at Johnston Island. The failure 

was traced to “over-current protection” devices that were installed in the 

system’s transformers. There were anecdotal reports that “hundreds” of burglar alarms in Honolulu began sounding at the same time.

76 

The cessation of atmospheric testing in 1962 forced scientists to seek 

other means to examine the EMP phenomena. Both transmission line and 

radiating simulators were developed to produce representative fields. While 

not exact replications of the post-detonation environment, they provided a 

great deal of data on coupling mechanisms, circuit vulnerabilities, and 

weaknesses in system design. They also provided the impetus for the exploration of EMP as a weapon.77 

During the Cold War, the Soviet Union developed an extensive research program in high-power RF technologies. Soviet work included the 

successful development of the Magnetically Insulated Linear Oscillator 

(MILO), a device which was invented in the United States, but later abandoned in the 1980’s. The Soviets also exploited the work of Andrei Sakharov on the Magneto-cumulative Generator (MCG) for the development of 

explosively-driven power supplies. Since the 1991, Russia and other 

newly independent states are reported to have used MCGs to drive ultrawideband and high power microwave sources, lasers, and rail-guns.78 

Concern in the West solidified in 1994 when General Loborev, Director of 

Moscow’s Central Institute of Physics and Technology, distributed a paper 

by A. B. Prishchepenko that described how to employ an explosivelydriven RF weapon. 

Characteristics. High power RF systems are distinct from traditional 

electronic warfare systems. Rather than simply deceiving the victim with 

random noise or false targets, the goal of both HPM and UWB devices is to 

overwhelm the ability of a target to reject or disperse RF energy, which then 

leaves the victim system susceptible to disruption or destruction.79 Rather 

than relying on the target system’s signal path as electronic warfare systems 

do, high power RF techniques exploit electrical pathways to vital subsystems. 

In general terms, there are two pathways that may be employed to reach 

a susceptible subsystem. The first path is the so-called “front-door” that di-
24 . . . Directed Energy and Fleet Defense 

rects energy at the antenna. If the microwave energy is directed at a frequency that falls within the design bandwidth of the system, the target may 

be particularly vulnerable since its receiver is designed to detect and process 

the relatively weak returning signals. Out-of-band signals may also couple 

with the antenna system and overwhelm the signal processor. While narrow 

band HPM systems can be particularly effective using front door techniques, their success relies upon an understanding of the target’s design 

characteristics. 

The second path of susceptibility is so-called “back-door” coupling. This 

refers to any radiation coupling that follows a path other than that which 

exists through the antenna. Cracks or gaps in an airframe, exposed wires, or 

any other conductive material can provide a path for energy to reach key 

electronic components. While back-door paths require higher energy levels 

before damage is likely to occur, they are typically much more difficult to 

eliminate. 

The increasing reliance on metal oxide semiconductor devices increases 

the vulnerability of electronic components to EMP effects.80 While there has 

been extensive work on the effects of a nuclear generated EMP, those data 

reflect the lower characteristic frequency band and longer pulses seen in 

nuclear detonations and may not be applicable to the disruption and damage 

caused by high-power microwave devices. For example, the shorter pulsewidths of HPM and UWB obviate the current protection methods used 

against nuclear EMP. While the strength of nuclear electromagnetic pulses 

decreases rapidly above the Very High Frequency (VHF) band (30-300 

MHz), UWB devices cover the spectrum from hundreds of megahertz into 

the gigahertz range. Moreover, HPM devices routinely operate at frequencies up to tens of gigahertz. The fact that the shorter HPM and UWB pulses 

are faster than the response time of typical limiters means that the targeted 

system can be damaged or destroyed before the protection circuit reacts. At 

the other extreme, there are devices with long duration (millisecond) pulses 

that can cause significant damage. 

Potential RF weapon sources may be categorized by their bandwidth, 

pulse duration, and the energy source used to drive the device. There are 

three types of pulsed power systems generally under study: capacitive, inductive, and explosive. As previously discussed, recent attention has been 

devoted to the possibility of developing explosively driven RF munitions. 

Power Systems. There have been proposals for RF devices that would 

convert the chemical energy of an explosive reaction into magnetic energy, 
Directed Energy and Fleet Defense . . .25 

which would then be converted into electrical energy, and finally into microwave energy. While this is an inherently inefficient process, chemical 

explosives are a readily available energy source. The projected yields of the 

proposed devices are relatively small.82 To be effective, the weapon would 

have to detonate relatively close to the target (within a kilometer or less) in 

order to exploit the inherent lack of shielding in most sensor and weapon 

systems today. 

An alternative approach is to develop electrically driven devices that can 

eliminate two of the energy conversion steps and can provide a multi-shot 

capability.

83 Early attempts were hindered by the need for a large external 

power supply and energy storage system, such as a massive bank of capacitors. These limitations may be overcome by emerging technologies. The 

first technology entails a set of solid state pursers developed at the Ioffe 

Physico-Technical Institute in St. Petersburg, Russia. The system uses nanosecond and picosecond switches to develop 10 nanosecond, 10 kHz pulses 

for a ground penetrating geological sensor. One observer has reported that 

such devices could be used to construct a briefcase sized, adjustable jammer 

that is capable of delivering 100 kilovolts per meter at 5 meters. Related 

technologies include a high-current electron accelerator known a RADAN 

that has claimed an output power in excess of 5 MW, using a 12 volt battery 

power supply, as well as the Russian built NAGIRA radar that demonstrated 

a 300 MW peak power.84 

Alternatively, pulsed power systems that use inductive storage devices 

are appealing because they can store more energy per unit volume with a 

magnetic field than an electric field. To date, limitations in switching technology have precluded their widespread use. Both inductive and capacitive 

pulsed power systems will require further development if they are to provide weapons with a multi-shot capability.

85 

Microwave Sources. A wide variety of HPM narrowband sources have 

been developed over the years. In addition to the magnetically insulated linear oscillator previously mentioned, a number of other technologies are possible.

86 Current technology has produced a 25-gigawatt ultra-wideband 

source, a 100-gigawatt UWB device is anticipated within a year, and finally, 

travelling wave devices are also being explored for UWB applications. 

Ultra-wideband Devices. Freed from the need to be precisely tuned at a 

particular frequency, ultra-wideband devices are generally limited by 

switching technology and antenna design. There are two common ap-
26 . . . Directed Energy and Fleet Defense 

proaches to switching devices. The first, spark gap switching, was described 

in congressional testimony as a candidate for use in a “homemade” Transient Electro-magnetic Device.

87 While it offers a simple and inexpensive 

solution, the device’s lengthy recovery time between firings makes it better 

suited for single shot applications.88 While the development of suitable solid 

state switches has been more difficult, there has been progress with the use 

of photoconductive semiconductor switches that are triggered by a laser. A 

number of other approaches are also under investigation. 

Antenna design for ultra-wideband systems poses unique challenges. The 

very nature of a wideband system makes interference with a number of 

friendly surveillance and communications systems possible. To avoid such 

problems the directionality (pointing) of the transmitting antenna is critical. 

Most current UWB systems use Transverse Electro-Magnetic (TEM) 

horns.89 A variation of the TEM horn, known as the Impulse Radiating Antenna (IRA), adds a parabolic reflector. The Phillips Research Site has succeeded in demonstrating an IRA that provides a conical beam whose width 

is approximately one-degree. By focusing the energy in such a narrow 

beam, the impulse radiating antenna makes it possible to dramatically reduce the potential for fratricide, thereby making the employment of an ultrawideband device feasible in an operational environment. Research continues 

into alternatives that would permit the use of conventional dispersive antennas by pre-distorting the signal so that the desired output is obtained. Additional theoretical work is attempting to develop an antenna with broadband 

characteristics that range from the low megahertz range to multi-gigahertz 

frequencies. 

Summary. While each of these devices has advantages and limitations, 

the significant progress made in the last ten years strongly suggests that high 

power RF weapons can be produced within the next two decades. A key 

factor will be the development of devices whose waveforms minimize atmospheric breakdown. Other critical technologies that require further development are reliable, compact, pulsed power systems, higher power microwave sources, solid state switching devices, and impulse radiating antennas. The development of planar arrays with electronic steering to support 

both HPM and UWB systems is highly desirable from an operational perspective.90 
Directed Energy and Fleet Defense . . .27 

Comparison of RF Weapon and High-Energy Laser Technologies 

Many researchers have recognized that these two forms of directed energy provide complimentary capabilities in the development of weapon 

systems. Lasers are precise; however, their precision requires complex 

pointing and tracking systems. By contrast, RF systems offer area coverage 

with less stringent demands for target tracking; however, the penalty is to 

reduce the ability to discriminate between friend and foe. While a narrow 

laser beam has the potential to deliver greater energy at point targets over 

long distances, such systems can be severely degraded by weather and atmospheric conditions. On the other hand, while RF systems are limited to 

substantially shorter ranges even under the best conditions, they have the 

distinct advantage of suffering only modest attenuation due to weather and 

atmospherics. 

The research community has made tremendous strides over the last decade. A reasonable estimate is that both technologies are on the verge of further advancements that will enhance their value as weapons. Nonetheless, 

the fundamental physical differences between lasers and RF systems leave 

the operational advantages of each relatively unchanged (See Table 1). 

While neither of these technologies is fully mature, nothing in principle 

precludes their successful development as “speed of light” weapons. Recent 

analyses have indicated that the volume, weight, power, and cooling requirements of these technologies may limit airborne and space-based applications for the foreseeable future.91 Nevertheless, the US Air Force Scientific Advisory Board is guardedly optimistic about the feasibility of developing laser and RF weapons for fighter aircraft over the next thirty years.92 

Cost is a constraint with the present state of the art, particularly for any 

application that involves a significant number of platforms. In the long term, 

however, cost does not appear to be an insurmountable obstacle. The continuing commercial demand for improvements in the manufacturing of 

electronic components is likely to reduce the cost of components. While it is 

unrealistic to expect that the trend toward lower unit costs over the last decade will continue unabated, the demands placed upon the commercial electronics market should further reduce costs.93 
28 . . . Directed Energy and Fleet Defense 

Table 1. Comparison of RF Weapon and High-energy Laser Technologies

94 

RF Weapons High-energy Lasers 

Generally affects targets from the inside out. 

Mechanism is electronic destruction or disruption. 

Generally affects targets from the outside in. 

Mechanism is typically structural destruction. 

Wavelengths from 0.1 cm to 3.0 m. 

Invisible. 

Wavelengths from 0.27 microns to 5 microns. 

Visible to infrared (invisible). 

Relatively weather insensitive. Clouds and dust 

are not major factors. 

Environmentally sensitive to clouds, dust, and 

molecular absorption. 

Monolith and/or phased emitters. Generally monolith. Phased arrays under development. 

Generally large apertures, metal antennas, 

ground planes. Relatively durable. 

Modest apertures, glass mirrors, coatings and 

cleaner transmitters needed. Optical surfaces 

more susceptible to damage. 

Relatively large beamwidths. (Minimum on the 

order of 1 degree.) Typically flood the target 

with radiation. Possibility for illumination of 

multiple targets simultaneously. 

Extremely narrow beams. Uses small laser spot 

to surgically attack individual target. Requires 

precise target tracking. Limited to engaging 

one target at a time. 

Both approaches share the following characteristics: 

Destructive power travels at the speed of light. 

Capable of graduated effects from degrade, disrupt, damage and destroy. 

Source: Adapted from Barry Hogge, Chief Scientist, Directed Energy Directorate, Phillips Research Site, “Assessment of the SAB Aerospace Expeditionary Force Studies Recommendations,” May 1, 1998. 

As previously discussed, there are certain physical limitations with both 

of these directed energy technologies that significantly limit their military 

utility. For lasers, the principal limitations are atmospheric effects, mechanical scanning, and the maximum power that can be delivered. The absorption and scattering effects will preclude lasers from becoming true allweather weapons in the near term, even if the transmissivity window in the 

one-micron region could be exploited. Moreover, any sensor limited to a 

single relatively narrow band is vulnerable to counter-measures.95 

Thermal blooming is the most significant long-term challenge because it 

offsets many of the advances in power generation. Beyond a certain point, 

simply adding more power is not the answer. Further research in pulse 

shaping and dwell times will be necessary to overcome these limitations. As 

the National Research Council suggested, it is unlikely that the ability to 
Directed Energy and Fleet Defense . . .29 

deliver laser power will keep pace with the efforts to harden the nose cones 

of missiles. Before deciding whether the challenge can be solved, one must 

understand that historically missiles have been successfully engaged when 

lasers are directed at control surfaces and fuselages from oblique aspects.

96 

It is likely that a missile, which maneuvers to avoid other defensive systems, 

could be engaged by a laser. 

Current laser systems generally employ mechanically scanned apertures, 

but these have two disadvantages. The first is to increase the response time 

required for mechanically slewing, or pointing, the laser. The second, 

seemingly mundane issue, is the increased complexity of providing a protective cover for the aperture that protects it from environmental damage 

while not interfering with the transmission of high-power laser energy. The 

development of large planar laser arrays, as proposed in the New World 

Vistas study, provides a long-term solution to both of these problems.97 

The evidence from the first phase of the USAF study “Directed EnergyApplications in Tactical Airborne Combat” (DE-ATAC) is that microwave devices have the greatest potential in the near term. This includes 

applications in enhanced munitions, large and small aircraft self-defense, 

and integrating directed energy into unmanned combat air vehicles (UCAV) 

for suppressing enemy air defenses (SEAD).98 

Nevertheless, RF directed energy weapons still face a number of physical 

limitations. As transmitted power is increased, high-power microwave 

weapons confront the problem of air breakdown. Current research efforts 

are devoted to identifying waveforms that permit the maximum transfer of 

energy without reaching the breakdown threshold. Propagation losses can 

limit the effective range of RF systems, since even a focused beam spreads 

dramatically as the range to the target increases.

99 

Narrow band HPM systems typically have better transmission characteristics and fewer problems with fratricide than wide band systems, but narrow band systems require some prior knowledge of the threat and can be 

defeated by hardening. However, ultra-wideband microwave systems offer 

broad coverage of the threat even when one has little or no knowledge of the 

enemy’s system. With less energy being transmitted at a given frequency 

(fewer watts per megahertz), current UWB systems have significantly 

shorter effective ranges than narrow band systems. Research continues in 

efforts to build a true “dispersion-less” antenna that would increase the tactical ranges of UWB systems without further complicating the fratricide/suicide problems.100 
30 . . . Directed Energy and Fleet Defense 

Any conclusions about the viability of directed energy weapons must be 

understood in the context of the potential applications. The United States 

has focused on the use of directed energy weapons for anti-missile defense 

(both cruise and ballistic). As the DE-ATAC study addressed, there are several other applications that could be adopted by potentially hostile nations. It 

is not prudent to forego the development of directed energy weapons because they do not provide a complete solution to the anti-missile defense 

problem. Finally, it is evident that directed energy devices offer a new form 

of weapons that can deliver lethal power at an unprecedented speed. The 

likelihood that some nation will choose to build such weapons means that 

U.S. forces will be placed in jeopardy if they are not able to respond to this 

threat. For now, RF weapons and high-energy lasers appear to offer the best 

methods for countering the threat of attack at the speed of light. 
Directed Energy and Fleet Defense . . .31 

V. Directed Energy and Fleet Defense 

This section focuses on a framework for understanding how directed energy systems may contribute to fleet defense, and in particular with developing a more robust capability against new generations of anti-ship cruise 

missiles. The broader argument is that the inherent flexibility of directed 

energy systems makes them attractive candidates for other missions, including the neutralization of small fast patrol boats, sensor blinding, and 

other anti-surveillance measures. 

Anti-ship Missile Defense 

As previously discussed, advanced anti-ship cruise missiles pose the 

greatest threat to major naval powers in the foreseeable future. Directed energy systems provide two primary mechanisms and one secondary mechanism for cruise missile engagement and destruction. The primary methods 

are to disrupt or disable the missile using electromagnetic effects produced 

by an ultra-wideband microwave system, or to destroy a non-maneuvering 

missile with a surface-to-air missile. Because of its susceptibility to environmental limitations, a laser system may be unavailable when needed. 

Therefore, direct destruction with a high-energy laser is defined as a secondary mechanism, even though it will be the first system to engage threats in 

tactical situations. 

An ultra-wideband microwave system can be used to induce the transient 

effects of disturbance and upset, as well as the more lasting effects of latchup or burnout.101 The specific effect is less important than the fact that some 

disturbance is introduced. The greater the missile’s speed and the lower its 

altitude, the more susceptible it will be to minor perturbations in its guidance and control system. Sea-skimming missile systems require extremely 

fast control systems to avoid flying into the water even in relatively benign 

weather. A Mach 3.0 missile (3000 feet per second) flying 30 feet above the 

sea travels approximately 150 feet during a 50 millisecond disruption. Thus, 

even a minor disturbance of the missile’s radar altimeter or guidance software could be sufficient to create a “hard kill” if the missile hits the surface 

of the sea. If sufficient energy can be deposited to induce latch-up or burnout, the probability of kill increases. An ultra-wideband source eliminates 

the need for specific knowledge about the enemy missile because it is not 

necessary to target specific mechanisms in the missile. The wider the fre-
32 . . . Directed Energy and Fleet Defense 

quency coverage of the UWB device means that it is more likely to disrupt 

or damage the missile. 

An alternative mechanism employs a high-energy laser system to detect, 

track, and engage the sensor that guides the incoming missile. For missiles 

coming in head-on, it may be difficult or impossible to obtain a structural or 

payload kill. While the radome itself may be susceptible to damage, the 

physical placement of the guidance and control systems within the missile 

body may preclude a direct kill.102 However, once the missile’s sensor system has been damaged or destroyed, it is more vulnerable to both microwave disruption and direct attack. Typically, cruise missiles are programmed to fly to the last known target location if sensor data are lost. 

When the ability of the missile to maneuver is eliminated, it dramatically 

increases the probability that a conventional surface-to-air missile, such as 

the RIM-116A, can destroy the missile. Alternatively, if an incoming missile is deprived of sensor updates, it will be unable to reacquire the target 

and adjust its track when its guidance system is momentarily disrupted by 

microwave illumination. 

Crossing targets, which are targets that approach a unit’s defensive perimeter tangentially, generally pose the greatest difficulties for conventional 

air defense missile systems, but these are also the most vulnerable to destruction with lasers. A variety of test programs have demonstrated that terrestrial and airborne laser systems can successfully engage missile targets in 

crossing scenarios.

103

 While such targets traditionally were engaged by area 

defense systems, the trend towards increasingly sophisticated anti-ship missiles means that point-defense systems must now confront maneuvering 

missiles. In collaborative defense, the attacker is faced with the dilemma of 

maneuvering to defeat point-defense missile systems and risking destruction 

by a high-energy laser. The alternative is to proceed directly at the target to 

minimize the ability of the laser to engage it, while maximizing the probability of successful engagement by a surface-to-air missile. Table 2 compares the performance of high-energy lasers against head-on and crossing 

missile targets. 
Directed Energy and Fleet Defense . . .33 

Table 2. High-energy Laser Lethality against Missile Threats104 

Kill 

Assurance 

Effective 

Range 

Type Kill Aim Point Engagement 

Head-on Crossing 

High 

Low 

Short 

Long 

Structural Propulsion System 

Structural Member 

No 

No 

Yes 

Yes 

Payload Warhead 

Propellant 

No 

No 

Yes 

Yes 

Aerodynamic Radome 

Control Surfaces 

Yes 

No 

No 

Yes 

Control System Autopilot 

Other electronic 

control systems 

No 

Yes 

Yes 

No 

Sensor 

Destruction 

RF & EO Seekers 

Imaging Sensor 

Yes 

Yes 

No 

No 

Sensor Dazzle E/O Seeker 

Imaging Seeker 

Yes 

Yes 

No 

No 

Source: Adapted from briefing materials provided by Mr. Young Cook, 

NRL, Washington, DC, from a presentation to the 1st Directed Energy 

Symposium, Kirtland AFB, New Mexico, November 6, 1998. 

The tendency to increase the speed and reduce the signature of anti-ship 

missiles makes it increasingly problematic to defend against these missiles. 

A Mach 4.0 missile skimming the waves at 3 meters could be engaged for 

approximately 20 seconds from the time that it became detectable. This 

leaves very little time for track detection, acquisition, identification, and 

hand-off to a weapon system, and in that case the time of flight of the intercepting missile significantly affects the success or failure of engagement. 

The defender has an inherent disadvantage because the intercepting missile 

must accelerate from zero to Mach 3.0+ in a matter of seconds. Even if the 

defending missile is fired at the moment the attacker crosses the radar horizon, the maximum intercept point will be approximately 7 nautical miles 

from the defended point. There is a finite amount of time to train and elevate the launcher for each engagement, as well as to initiate the ignition sequence for each missile fired. With anti-ship missiles attacking in quick 

succession, the defender’s cycle time is highly compressed, which makes a 

defense against a “stream raid” more difficult even with an autonomous 

weapon such as the RIM-116A. 
34 . . . Directed Energy and Fleet Defense 

Attempts to counter this vicious cycle with conventional missile developments are unlikely to succeed because the same technologies that improve 

the speed, agility, and response time of the defender’s missiles are just as 

likely to improve the attacker’s performance. By using directed energy systems, the defender has a speed advantage on the order of roughly six orders 

of magnitude to reduce the “time of flight” required to reach the approaching missile. In the 2-5 seconds required to deposit laser energy on a target, a 

Mach 4.0 missile will travel only about 3.5 nautical miles. Given a sufficiently powerful laser in this scenario, the attacker could be destroyed at 16-

18 nautical miles from the defending platform, which is more than twice the 

best distance attained with conventional systems.

105 

As previously discussed, air breakdown will generally limit ultrawideband microwave systems to shorter ranges than laser systems. However, microwave systems still enjoy a significant speed advantage over conventional missiles. In addition, the typical maximum dwell time that is necessary to produce disruptions within the guidance package of the attacking 

missile is on the order of 600 milliseconds or less. 

Unfortunately, drastically reducing the “time of flight” for directed energy does not eliminate the requirements for detection, acquisition, and 

identification. These processes dominate the engagement sequence for a directed energy system. Unless mechanically scanned surveillance systems, 

such as the SPS-48E, are replaced with fixed planar arrays, the defender 

may lose 3-4 miles of the battle space before it has the first opportunity to 

detect the target.106 This time is critical in the case of cruise missiles that 

have dramatically reduced signatures. While laser trackers and other electrooptical devices will produce marginal improvements in acquisition and 

tracking times, each has vulnerabilities to environmental factors. Nevertheless, the fact that directed energy weapons reduce the “time of flight” gives 

the defender that much more time to detect, identify, and engage the target. 

Anti-aircraft Defense 

Cruise missiles approaching a ship typically leave little doubt as to hostile intent. However, aircraft are more problematic. There may be a significant number of so-called aircraft, which are neither friend nor foe, but operate within the battle space, which explains why “track identification” is 

critical in such situations. During flight operations, aircraft carriers have the 

additional challenge of distinguishing between hostile and friendly aircraft. 

Electronic identification systems are of some help, although no electronic 
Directed Energy and Fleet Defense . . .35 

system fully addresses the problems of cryptographic compromise and battle damage. The drastic reduction in “time of flight” of directed energy systems allows a more rigorous identification process to be employed, and 

thereby decreases the probability of fratricide. 

Hostile tactical aircraft carrying laser guided munitions or short-range 

air-to-surface rockets are generally a lesser-included case in the air defense 

problem. The preferred means of engaging tactical aircraft is likely to be 

other tactical aircraft, given the latter’s ability to obtain a visual or multisensor confirmation of the target’s identity at far greater ranges than any 

surface based sensor. 

While tactical aircraft are subject to destruction in much the same fashion as cruise missiles, there are some substantive differences. For example, 

the destruction of the radome of a tactical aircraft is likely to have little impact on its aerodynamic survivability. In fact, its destruction may not diminish the effectiveness of air launched anti-ship missiles that are equipped 

with active seekers. On the other hand, the aircraft’s control surfaces, fuel 

tanks, and weapons stores offer a variety of aim points, even when approaching the ship head-on. If environmental conditions permit, the laser is 

likely to be the weapon of choice. Its ability to precisely track the target and 

its short “time of flight” minimize the risk of fratricide. It also provides the 

options for engaging missiles at long-ranges, which means that the defender 

may be able to fire fewer weapons and thereby slow the rate at which the 

ship’s magazine is depleted. As a back up, the Rolling Airframe Missile 

provides an all-weather capability for aircraft engagement. 

Microwave systems, as with the CIWS that they would replace, are the 

least desirable option for anti-aircraft defense. Shipboard ultra-wideband 

microwave systems are not likely to have lethal effects for two reasons. 

First, an aircraft that fires a short-range tactical missile or lofts a laserguided bomb will likely remain outside the range of an UWB device. Second, manned aircraft tend to incorporate far more robust and redundant 

control systems than unmanned missiles. It would require the near simultaneous disruption of two or more independent flight control computers to 

adversely affect an aircraft with a typical digital flight control system. The 

effects of microwave defensive systems are likely to be far more subtle. The 

most vulnerable systems are those with antennas, such as those that support 

communication and sensor systems. 

The disruption and degradation of aircraft sensors and mission computers 

will make it more difficult for enemy pilots to attack the carrier successfully. The more sophisticated the aircraft, the greater the probability that the 
36 . . . Directed Energy and Fleet Defense 

mission computer will control the essential sub-systems. For example, seekers on externally carried stores are particularly vulnerable to disruption. To 

preclude inadvertent destruction of the launch platform, most air-launched 

missiles are required to pass an internal self-test before it will accept a 

launch enable signal. Any disturbance of the missile guidance and control 

circuitry may be sufficient to preclude the release of the weapon. With the 

exception of fixed-fin, forward firing rockets and so-called “dumb iron 

bombs,” any weapon is subject to the same type of microwave effects that a 

cruise missile will encounter in the terminal phase. Microwave systems may 

also offer a limited defense against unguided ballistic weapons, such as 

bombs and rockets, by damaging the fusing mechanism or causing premature detonation. 

Directed energy weapons would provide an enhanced capability against 

the category of aircraft that are known as “low, slow flyers.” This typically 

includes light civil aircraft, ultra-lights, and helicopters that are characterized by relatively low speeds (less than 300 knots), low infrared signatures, 

and few if any distinctive electronic emissions.

107 If environmental conditions permit, the laser provides the system of choice. An integrated laser 

tracker, such as the Sea Lite Beam Director, can provide an image of the 

target at long range. In the past, light aircraft and helicopters have exploited 

their small size to obtain a visual identification of the carrier or other high 

value units before they could be positively identified. The laser directortracker shifts the advantage back to the surface ship, because once the target 

is positively identified as hostile the laser can destroy it before the target can 

approach friendly units. 

If the target’s identity cannot be determined, or if the rules of engagement preclude its destruction at long range, the ultra-wideband microwave 

system has a high probability of successfully engaging the target in the terminal phase. The propulsion systems of light civil aircraft and ultra-lights 

are particularly vulnerable to disruption. If the aircraft is being used in a 

kamikaze role, there is the additional possibility that the use of UWB microwave weapons could cause the premature detonation of its explosive 

cargo. 

Military helicopters are another problem. While lightly armed reconnaissance helicopters, without anti-ship missiles, may be countered in the same 

manner as other low, slow flyers, those equipped with anti-ship cruise missiles pose a threat similar to tactical aircraft. Fortunately, when configured 

with missiles, the tactical ranges of helicopters are generally limited and, if 

based ashore, are unlikely to reach carriers that are operating 100-150 nauti-
Directed Energy and Fleet Defense . . .37 

cal miles off the coast. Nevertheless, this threat must be considered. For a 

helicopter to employ its weapons at their optimum ranges, it must identify 

the target vessel by some means. Unless it has third party targeting, the helicopter will have to enter the ship’s “surveillance volume,” which provides 

an opportunity for the defender to detect and identify the helicopter. Once 

again, if environmental conditions permit, the laser system offers the optimum combination for long-range identification and rapid engagement. Otherwise, the engagement options are the same as for tactical aircraft. 

Anti-Surface Ship Options 

The aircraft carrier must also be able to defend itself against hostile surface craft. While the primary means of destroying enemy combatants is 

generally anti-ship missiles and other guided munitions launched from carrier based aircraft, every high value unit needs a method of self-defense that 

is not constrained by flight operations. The Seasparrow has a limited antiship capability.

108

 The potential effectiveness of the RIM-116A in a countersurface mode is unknown, but the relatively small size of the warhead (25 

lbs) is likely to be a limiting factor.109 While the addition of directed energy 

systems is unlikely to produce a mechanism for directly engaging surface 

combatants, there may be new opportunities for neutralizing such threats 

with non-lethal measures. As with air defense, one of the greatest advantages of a laser director-tracker is its ability to illuminate and visually identify targets at long range. 

Non-lethal Capabilities 

Directed energy offers the potential to disrupt the sensors of a surface 

combatant at the maximum line of sight. The rapid responsiveness of directed energy weapons makes them particularly useful against high-speed 

patrol boats or surface-effect craft that can effectively out-maneuver the 

harassing fire of conventional gun systems.110

 The physical characteristics 

of directed energy systems give the defender greater control over the effects 

generated than any conventional weapon. Lasers have the ability to travel 

great distances, and the narrow beam and excellent beam control provides a 

high degree of certainty that the energy will be deposited on the target. Ultra-wideband microwave systems have a broader beam (on the order of one 

degree), but are limited in range by the upper limits imposed by the atmospheric breakdown that occurs at higher power levels. Both systems can be 
38 . . . Directed Energy and Fleet Defense 

employed in scenarios in which the risk of collateral damage or that the energy could be traced back to the ship would preclude the firing of conventional weapons. 

Anti-Fast Patrol Boat Operations. While the destruction of radomes, 

antennas, and waveguides can render enemy radar unusable, electro-optical 

sensors are even more vulnerable than RF devices to laser destruction. Destructive techniques provide essentially the same level of protection as 

jamming without exposing the defender to attack by an anti-radiation missile. Unlike a jammer, the laser can be secured once the sensor is destroyed. 

The narrow beam of a laser weapon makes it less liable to counter-detection 

than a laser illuminator. Depending upon the characteristics of the laser and 

the sophistication of the techniques used, the opponent may not discern the 

cause of the sensor failure until it can examine the waveguide or antenna 

itself.

111 Given the lethal ranges of fast patrol boats, microwave systems 

may be able to do little more than disrupt sensitive electronic surveillance 

and communications systems. 

Counter-terrorist Operations. On the other hand, small craft such as 

“boghammers” or “zodiacs,” that attempt to harass or attack the carrier may 

be neutralized by directed energy devices that are used for anti-personnel or 

anti-equipment purposes. Non-lethal options are particularly important 

when operating in areas where the use of conventional weapons may be precluded. For example, microwaves can neutralize the electrical systems of 

the attacker’s boats without creating an international incident because the 

potential terrorist would not have any tangible proof that defensive measures were taken.112 

Submarine Defense. There is a theoretical possibility that a laser directortracker could be used to detect and destroy submarine periscope sensors. If 

used for nothing else, it immediately places the submarine on the defensive 

because it sends an unambiguous message that the submarine has been detected and identified. As with other anti-submarine weapons, it is essential 

to ensure that friendly submarines are not mistakenly attacked. This concept, however, may not prove to be practical because the delay introduced 

by placing a human operator in the loop would assure that all but the least 

competent submariners would not be engaged.113 

Counter-surveillance. Directed energy weapons add a new alternative for 

dealing with both hostile and third party reconnaissance systems. The same 
Directed Energy and Fleet Defense . . .39 

counter-sensor capabilities that can be employed for air and surface defense 

can also be used to neutralize long-range surveillance systems. For example, 

a maritime patrol aircraft that is supporting third-party targeting for coastal 

anti-ship missile batteries could have its electro-optic sensors destroyed and 

its radar and communications systems disrupted. Similar techniques could 

be used to discourage surface vessels from functioning as intelligence collectors.

114 Ultimately, a ship-based laser system could be employed to disable surveillance from space-based platforms. Such a capability has broad 

tactical and strategic implications. 

Directed Energy Options 

The space, weight, power, and cooling requirements of directed energy 

technologies have a significant effect on the transition from engineering development to operational weapons. While the technological community has 

made impressive progress in recent years, both systems require large apertures to focus the transmitted energy as well as power distribution systems 

that are capable of providing megawatts of power. These physical constraints place a limit on the types of platforms that can be economically 

modified to accommodate them. While much of the historical work with 

directed energy systems focused on anti-ballistic missile applications, it is 

interesting to note that the employment of directed energy systems in a direct-fire, short-range, tactical air defense mode would simplify the challenges of detection, tracking, and power generation. 

There are several possible ways to use directed energy to defend a ship. 

The purpose of this study is not to propose a definitive plan, but to establish 

a framework for understanding the potential capabilities and limitations of 

directed energy within which strategists and technologists can begin to assess the impact on “fleet tactics.” As this study will argue, Nimitz class nuclear powered aircraft carriers (CVN) have a projected service life of over 

fifty years, and each carrier is scheduled for mid-life refueling and major 

overhaul at the 23-25 year point. As the largest naval vessels in the world, 

with dual nuclear power plants, these ships provide a viable option for the 

initial deployment of tactical directed energy systems. 

As presently configured, Nimitz class CVN’s employ a combination of 

NATO Seasparrow surface-to-air missiles and the Close-in-Weapon System 

(CIWS) Gatling gun for self-defense.

115

 While both the CIWS and the 

Seasparrow systems have undergone numerous upgrades since they were 

developed in the 1970’s, their continued effectiveness is of concern.116

 The 
40 . . . Directed Energy and Fleet Defense 

replacement of these systems with a new generation of self-defense hardware offers a way to ensure the survivability of the carrier in the face of 

more demanding threats. The current plan calls for the replacement of the 

CIWS with the RIM-116A Rolling Airframe Missile system and the possible replacement of the NATO Seasparrow System with the Evolved 

Seasparrow, if the latter ever comes to fruition. 

This study considers four alternatives for integrating directed energy 

systems into the self-defense suite of an aircraft carrier. The first option involves the removal of the conventional gun and missile systems and their 

replacement with ultra-wideband microwave systems. The consensus, as 

expressed in the interim report of the DE-ATAC Study, is that in view of 

significant progress in high power microwave technology in the last decade, 

microwave systems offer the best option for an all-weather system. The two 

major concerns with this approach are the limited effective range of microwaves as a result of atmospheric breakdown at high powers and the inherent 

risks of depending on a single technology for a critical defensive system. 

The second alternative is the replacement of existing systems with highenergy lasers. The deuterium fluoride laser is one of the more mature technologies that has undergone extensive testing under both the MIRACL and 

Nautilus programs. The high-energy laser has demonstrated that it has a capability against various tactical targets. The principal disadvantages of this 

approach are the laser’s susceptibility to environmental effects, and its potentially limited capability against certain head-on targets. In maritime operations, the primary defensive system must be able to function satisfactorily wherever the ship is operating. If it relied solely upon a high-energy laser system, the ship could be left defenseless for several days in the event of 

severe weather. 

The third option is to replace existing systems with a combined suite of 

ultra-wideband microwave systems and high-energy lasers. Under suitable 

environmental conditions, the long-range capabilities of the laser would 

complement the short-range, all-weather capabilities of the microwave system. The unique advantage of this option is that both systems have essentially bottomless magazines, which eliminates the need to reload in combat. 

The final alternative, similar to the third, combines both high-energy laser and ultra-wideband microwave systems, and includes a conventional 

surface-to-air missile capability. This combination provides a robust set of 

self-defense capabilities that will function under a number of operational 

and environmental conditions. As part of this option, the Rolling Airframe 

Missile system provides a proven system that minimizes the risks associated 
Directed Energy and Fleet Defense . . .41 

with the incorporation of directed energy systems that are still in development. This study concludes that the fourth option provides the best alternative for a defensive suite that will meet the challenges of the first half of the 

twenty-first century. It provides the framework for this study’s examination 

of these directed energy concepts. The recommended option calls for replacement of the existing self-defense suite with two laser tracker director 

systems, four ultra-wideband microwave arrays and three Rolling Airframe 

Missile (RIM-116A) launcher systems. With three NATO Seasparrow 

magazine launcher assemblies, six associated radar directors and four CIWS 

mounts, the present self-defense suite contributes substantially to the ship’s 

topside weight.117 The weight, space, and power budgets allocated to the 

existing defensive systems appear large enough to accommodate the directed energy systems under consideration. 

The Rolling Airframe Missile is programmed to replace the current 

CIWS and Seasparrow systems.118 Three Rolling Airframe Missile magazine launchers could replace the three Seasparrow magazine launchers and 

nearly triple the number of missiles available.119 Already fielded on large 

amphibious assault ships such as the Wasp class, it complements directed 

energy systems under development with a capability that has been tested in 

world-wide naval operations. Equally important is the collaborative kill 

mechanism that exists when it is employed in conjunction with a highenergy laser. 

The two laser tracker-directors could replace a pair of Seasparrow directors. Using an approach similar to the Sea Lite Beam Director and the 

Airborne Laser, each tracker-director would include a fully integrated system comprised of an infrared search sensor, high resolution telescope, acquisition tracker, track illuminator laser, fine grain tracker, and the weapon 

itself.

120 Locating the laser tracker-directors on the carrier’s island structure 

maximizes the height of the laser aperture, keeps it out of the surface duct 

(thereby reducing attenuation due to moisture in the duct), and minimizes 

exposure to heavy sea spray. 

All CIWS mounts would be removed and be replaced with electronically 

steered planar arrays for the ultra-wideband microwave systems. Large planar arrays have demonstrated their environmental tolerance in the AEGIS 

cruiser and guided missile destroyer applications. Installed immediately 

below the flight deck, the arrays would at approximately the same height 

above the sea surface as the radar arrays on the latter classes of ships, while 

still providing a degree of physical isolation from other communication and 

sensor systems. An electronically scanned planar array is the preferred 
42 . . . Directed Energy and Fleet Defense 

choice for minimizing response time and reducing mechanical complexity. 

However, if the development of a broadband planar array is not practical 

technologically, then the impulse radiating antenna, which has been demonstrated successfully by the Phillips Research Site, can be used. The current 

CIWS sponsons can provide satisfactory fields of view for mechanically 

steered, impulse radiating antennas. If one employs the same general arrangement as used in the current defensive systems, then redundant defensive coverage can be provided. 

The Nimitz class CVN propulsion plant is designed to provide steam for 

the aircraft catapult launch systems, as well as routine propulsion requirements, and to do so with a single reactor. The dual reactor configuration 

provides a substantial power margin. With appropriate modifications to the 

ship’s electrical power distribution system, the power demands for any foreseeable directed energy system could be met. Unlike terrestrial and airborne 

applications, a seaborne system has the advantage of being able to use seawater as a primary or secondary cooling medium. Using the current engineering models for aircraft carriers as a point of reference, a reasonable assumption is that these directed energy systems will not require any major 

structural redesigns. Given the sheer size and the margin of power available, 

the CVN is the best-suited warship to integrate the directed energy technologies that are under consideration. 

This conservative approach permits the Navy to examine the capabilities 

of directed energy weapons while providing a more effective defensive 

system against advanced cruise missiles. It would also enable the Navy to 

assess the synergy between high-energy lasers systems and the Rolling Airframe Missile against sophisticated, high-energy missiles. This approach is 

consistent with the incremental introduction of using more advanced directed energy concepts, such as electro-magnetically-enhanced warheads for 

surface-to-air missiles, for protecting naval forces. 

Summary 

The incorporation of three separate defensive systems, each capable of 

providing 360-degree coverage, would improve the ability of aircraft carriers to defend themselves against multi-axis saturation attacks. Overlapping 

“fields of fire” and rapid re-engagement times will eliminate the vulnerability that exists at the seams where the coverage of defensive systems converge. The essentially bottomless magazines of the laser and microwave 

systems make stream raid tactics of dubious effectiveness.121

 The larger 
Directed Energy and Fleet Defense . . .43 

magazine of the Rolling Airframe Missile launchers should require less frequent re-loading, and thus further reduce the vulnerability of the ship to 

stream raids. If re-loading operations can be deferred until there are more 

favorable environmental conditions, the laser system can provide long-range 

defense while the missile launcher is reloaded.122 Not unexpectedly, there 

are natural synergies among the three weapon systems, as shown in Table 3. 

If environmental conditions permit, the CVN will have the added capability of visually identifying aircraft or surface vessels with the optical sensors associated with high-energy lasers. Other possibilities include the integration of this sensor data to permit cueing of the Block 1 RIM-116A. Directed energy systems also offer a range of non-lethal options, ranging from 

blinding the sensors on surveillance aircraft to an anti-personnel capability 

against terrorist speedboats. The rapid response and potentially covert nature of directed energy systems makes them the weapon of choice in certain 

politically sensitive scenarios, such as the exercise of the right of innocent 

passage or while anchored within the territorial waters of another nation. A 

suite of high-energy lasers and radio frequency weapons when combined 

with a modest conventional surface-to-air-missile capability gives the CVN 

a more credible defensive capability across a broader range of threats than 

comparable suites of weapons. 
44 . . . Directed Energy and Fleet Defense 

Table 3. Complementary Weapons Matrix123 

UWB Microwave HEL 

(RIM-116A) 

RAM 

Range Head-on 

Threat 

Crossing 

THREAT 

<.5 - 7 km 

<5 km 

<15 km 

.3 - 10 km 

Aim point Guidance system 

Flight controls 

Signal processor 

Radome 

Control surfaces 

Warhead 

Not Sensitive 

Sustainability 

(numbers of shots per 

reload) 

Essentially 

unlimited 

Hundreds 21 

(per launcher) 

Threat 

Maneuvering/Speed 

Not affected Not affected Challenged 

Atmospheric 

Conditions 

Minimal 

Sensitivity 

Sensitive Minimal 

Sensitivity 

RF Countermeasures Minimal 

Sensitivity 

Not affected Challenged 

Low RCS Minimal 

Sensitivity 

Not affected Sensitive 

Crossing/Head-on 

Profile 

Not affected Easier/harder Harder/easier 

Source: Author. 
Directed Energy and Fleet Defense . . .45 

VI. New Concepts for Employing Naval Forces 

The legacy of the Second World War and the years confronting a “blue 

water” Soviet fleet has influenced how the U.S. Navy formulated its operational concepts for the twenty-first century. Naval expeditionary operations 

are based on the carrier battle group and an amphibious ready group. As 

Captain Wayne Hughes described in his classic Fleet Tactics: Theory and 

Practice, one of the principal naval lessons of the Pacific campaign of the 

Second World War was the need for defensive firepower. This led to the 

massing of carrier battle groups into the multi-carrier battle forces that remain the centerpiece of U.S. Navy operations more than fifty years later.124 

During the cold war, the U.S. Navy and its NATO allies refined the concept of defense in depth to meet the ever-growing challenge from the Soviet 

fleet. Rings of fighter aircraft, AEGIS cruisers and destroyers, and ultimately point defense systems, such as the Seasparrow and Mark-15 CIWS, 

were employed to defend high-value units. When confronted with regimental raids of Badgers and Backfires, long range anti-ship missiles, such as the 

SS-N-12 and the SS-N-19, and the omnipresent submarine threat, it was expected that defending aircraft and escort ships would be lost. Regardless of 

the maneuver employed to reach the engagement, the outcome would have 

been determined by attrition, much as it was for Nelson almost two centuries years earlier. 

As noted previously, Naval Doctrine Publication 1 emphasizes the importance of maneuver warfare, which it describes as the more preferable and 

effective approach to war.125 While there have been lengthy discussions of 

whether naval warfare is inherently based on attrition, maneuver, or a hybrid of the two, the fact remains that current trends in both tactics and technology are oriented toward a layered defense for a multi-carrier task 

force.126 The model today remains much as it was in the past in which maritime dominance is attained by establishing control of the sea through 

sweeping away one’s opponents. The influence of Mahan, which relied on 

massing decisive firepower, seeking the enemy, and destroying him, remains strong. The question that must be asked is whether this is the best 

means to defeat the most likely threats that will emerge in the next thirty 

years. 
46 . . . Directed Energy and Fleet Defense 

Anticipating Opponent Behavior 

The late John Boyd never wrote about naval warfare or fleet tactics, but 

his “A Discourse on Winning and Losing” offers several powerful ideas for 

naval thinkers.

127

 Boyd examined land combat over the last three millennia 

in the context of Sun Tzu’s philosophy of war. The result of his analysis 

was a synthesis of apparently disparate lines of thought into a model that 

describes the reasons for the successes achieved by non-traditional forces in 

the twentieth century.

128 It does not offer an explanation for the historic successes of the United States Navy, but it outlines a model that could be used 

by future adversaries to confront the United States. Boyd defined the critical 

elements of success as “variety, rapidity, harmony, and initiative.”129 

The trend in modern naval warfare in the twenty-first century, as previously noted, will likely involve states which seek to deny control of some 

portion of the sea to the powerful navies, whether at a critical choke point or 

in the waters adjacent to their coasts. Unwilling or incapable of making the 

investment needed to command the sea, these adversaries will rely on sophisticated, inexpensive weapons to raise the stakes against the expensive 

multi-purpose forces of the major powers. After confronting a global superpower at sea for a generation, there is a real danger of viewing naval operations against smaller states as a less significant enterprise. However, this 

assumption could prove to be a tragic miscalculation. 

As Sir Julian Corbett observed almost 100 years ago, the strategy for a 

weaker opponent may be to deny the more powerful adversary the opportunity for a decisive battle. Enemy patrol boats hiding in fjords or caves can 

remain a “fleet in being” with little probability of being successfully engaged by conventional means. The dominant naval forces may never have 

the opportunity to annihilate the enemy’s forces in a single crushing 

blow.130 Instead, minor combatants may seek to engage in military actions 

under conditions in which an asymmetric exchange appears feasible. There 

are several historical precedents, including the Japanese success at the Battle of Tassafaronga in 1942 and the German successes against the Bergen 

convoy in 1917, both of which are exemplars of asymmetric attacks that 

produced devastating results.131 The danger lies in the tendency to overlook 

these incidents and to dismiss them as “accidents of war.”132 

As an example, consider the havoc that four corvettes, each firing four 

supersonic anti-ship cruise missiles, could wreak on a carrier battle force. 

While perhaps only one missile might hit, the prospect of a single hit against 
Directed Energy and Fleet Defense . . .47 

a major U.S. combatant or auxiliary could be sufficient to dissuade the 

United States from further action.133 After the successful operation against 

Libya in 1986 and against Iraq in the 1991 Gulf War, it is unclear how the 

American public would react to losses on the scale that the British suffered 

during the Falklands conflict. 

Toward Dispersed Tactics for Naval Forces 

The solution to this challenge may be found in a fortuitous confluence of 

tactical and technological developments. The United States and its allies 

have the unique opportunity to use directed energy technologies, which are 

sufficiently mature, in the development of new “fleet tactics” for confronting the asymmetric naval opponent.134 This does not imply that the U.S. 

Navy should abandon the lessons learned from the years of confronting a 

global naval power. On the contrary, the Navy must retain its ability to deal 

with potential competitors as well as those nations that are capable of 

matching its forces on a regional basis. Nonetheless, it is increasingly evident that there will be numerous situations in which a new approach will be 

needed if the United States is to defeat unconventional opponents. 

Operational Maneuver From The Sea is developing a new doctrine and 

equipment to meet the challenges faced by classic amphibious operations.

135 

Building on the MV-22 Osprey, the advanced Amphibious Assault Vehicle 

(AAAV), and an improved Landing Craft Air Cushion (LCAC), the Marine 

Corps is committed to the concepts of “ship to objective maneuver” and 

“over the horizon assault.”136 The result is that the doctrine of amphibious 

warfare has been fundamentally reshaped. In the future amphibious forces 

will no longer be constrained to a small set of beaches that are suitable for 

conventional landing craft. For supporting naval forces, the ability to remain 

at a significant distance offshore increases the freedom of movement, introduces uncertainty in the enemy’s targeting, and provides opportunities for 

deception.137 What is needed is a shift from classic battle group tactics toward the development of a new conceptual framework for carrier operations. 

A traditional task force operating in a defensive screen presents a readily 

discernible pattern that an adversary can discover with spaced-based sensors 

as well as radar, acoustics, and electronic surveillance. The detection of a 

single battle group unit helps to orient the enemy’s search, while the detection of additional units informs the adversary of the location of these highvalue units. A more structured naval formation is more readily discernible. 
48 . . . Directed Energy and Fleet Defense 

Hughes was even more blunt, stating unequivocally, “a major consequence 

of massing for defense is the certainty that the enemy will be aware of the 

fleet and its general location.”138 The clustered defenders could become an 

opportune target because their very proximity hampers their ability to engage targets without fratricide.

139 In the historic confrontations between 

major battle fleets, escort vessels serving in the screen were, by necessity, 

expendable in the defense of the capitol ships. What may have been an acceptable risk in the past is no longer prudent in cases that do not involve 

vital U.S. interests. 

The answer may lie in the use of a dispersed force that combines the inherent mobility of the carrier with a robust self-defense capability. Freed 

from the requirement to support amphibious operations within sight of land, 

the carrier gains a new opportunity to exploit its inherent speed, flexibility, 

and self-sufficiency. Instead of a classic battle group, a carrier and a nuclear 

powered submarine could operate in tandem. The two vessels make a natural pair that can optimally employ the mutual strengths of speed, reduced 

logistical needs, and the ability to dominate the air, surface and sub-surface 

environments. Freed from the slower moving escorts that require frequent 

refueling, the carrier can sustain comfortable cruising speeds of 20-25 knots 

on an indefinite basis. Capable of sprinting at higher dash speeds, the carrier 

has the ability to introduce substantial uncertainty in the calculations of 

those who seek to target it. Even when operating within a relatively small 

90-degree sector at ranges of 100 to 150 nautical miles from an enemy’s 

coast, the carrier is operating in an area greater than 10,000 square miles in 

which it must be found. The ability to create ambiguity and confound the 

enemy reduces the carrier’s vulnerability to attack from both cruise missiles 

and theater ballistic missiles. And dispersion minimizes the risk that more 

than one unit would be exposed to chemical or biological attack. 

The ability to exploit the inherent flexibility and mobility of naval forces 

will compel the adversary to fight on the defender’s terms. An opponent that 

is forced to fight further out to sea increases the advantage to the United 

States and its allies.

140

 Another advantage of a dispersed force is the fact 

that hostile surveillance units, when confronted with a single contact rather 

than a formation, must seek some additional confirmation of the identity of 

the unit. When the opponent is uncertain, it effectively shifts the advantage 

to the defender, which now gains more time to identify and destroy the attacker. 

Sea-based aircraft will likely remain the most effective means for destroying hostile patrol craft and tactical aircraft at extended ranges. At those 
Directed Energy and Fleet Defense . . .49 

times when the use of fixed or rotary wing aircraft is not possible, the defensive flexibility of directed energy weapons enhances the carrier’s survivability. The inclusion of the advanced optical sensors that are associated 

with high-energy lasers will help to positively identify ships and aircraft 

within the battle space and do so at greater ranges, which further shifts the 

balance in favor of the defender. 

As the U.S. Navy continues to shrink in size and increases the capabilities of individual units, there will be natural conflicts in the missions performed by these units. Consider, for example, the case of the AEGIS 

cruiser. During the Cold War, a cruiser was often assigned to the mission of 

terminal air defense of the carrier, but that mission is now an unaffordable 

luxury. In the next decade, that same cruiser is likely to have the role of 

power projection as a launch platform for Tomahawk cruise missiles, an air 

defense mission for protecting an amphibious force, and quite possibly a 

critical role in theater ballistic missile defense.141 It is highly unlikely that 

any of these missions will be best performed by stationing the cruiser at a 

distance of 5000 yards from the carrier. The AEGIS guided missile destroyers, which are replacing earlier generations of guided missile frigates, share 

these missions as well as other duties, including maritime interception operations and commerce protection. Using sophisticated multi-mission surface combatants to form a defensive ring of steel around carriers reduces 

their theoretical capability in combat. 

The danger is that the attempt to strike a compromise among the diverse 

missions performed by these naval platforms is likely to help the adversary 

pinpoint the location of the naval force. The reason is that each mission undertaken by units of a classic battle group imposes certain physical constraints on the group’s location. The carrier must be within the combat radius of its aircraft to project airpower; the cruiser that launches land-attack 

cruise missiles must be within range if its missiles are to reach their targets; 

and the ballistic missile defender must be positioned along the likely trajectory of attacking missiles to intercept the targets. While individual missions may be accomplished while operating over hundreds or thousands of 

square miles, there is likely to be a relatively narrow area from which all of 

these missions can be accommodated simultaneously. By identifying all of 

the missions assigned to a battle group, an enemy can then define the probable location of the fleet and proceed to target it. 

Dispersion also facilitates the use of deception. As observed by the classic Chinese strategist Sun Tzu, the target is the enemy’s mind and if an enemy is confused, the only hope for success is luck. The goal is to present 
50 . . . Directed Energy and Fleet Defense 

one’s foes with an image that they expect to see. The deception might be as 

simple as decoys that lead enemy aircraft to an AEGIS cruiser, or it might 

be as complex as a full-fledged amphibious feint. These are not new tactics, 

but are classic tools that become more effective when the force is no longer 

constrained to engage in set piece defensive arrangements.142 Old tactics 

become more effective with technological advances. The combination of 

multi-spectral passive sensors, Block 1 Rolling Airframe Missiles with dual 

passive seekers, and high-energy lasers with low probability of intercept 

would strengthen the ability of the carrier to conduct flight operations without electronic emissions.143 Armed with these tools, the carrier is no longer 

forced to choose between covert operations and robust defense. 

The unmatched capability of the U.S. Navy to provide the logistics that 

are necessary for tactical flexibility has contributed to its success as the preeminent naval power. However, as the supporting logistics become more 

complex the naval force itself becomes more vulnerable. The nature of replenishment operations, which are highly structured events, is to establish 

operational patterns that can be discerned by an adversary. While ships replenishing at sea can maneuver, changes in course and speed must be carefully executed. If attacked, the replenishing force is limited in the number of 

responses available and the speed with which they can be executed.

144 

The conceptual basis behind the U.S. Navy’s attempt to build nuclearpowered carrier task forces during the 1960’s was the principle that a selfcontained combat force is more agile and better able to seize the initiative. 

While this proved financially challenging, it has strengthened the reasons 

for minimizing the requirement that carriers refuel their escorts at sea. 

A self-defense suite that includes directed energy weapons will allow the 

carrier battle force to enjoy the defensive advantages of dispersion, while 

exercising its unique ability to concentrate offensive naval striking power.145 

The combination of fixed wing aircraft, helicopters, and unmanned air vehicles in a dispersed force can keep the adversary off-balance because it can 

strike from multiple axes with no apparent pattern. By appearing simultaneously over a number of targets, the combat aircraft on the carrier can put 

pressure on the adversary and thereby introduce confusion. Sea-based air 

power gives the U.S. Navy an unmatched ability to defeat its enemies.

146 
Directed Energy and Fleet Defense . . .51 

Anticipating Countermeasures 

An inevitable law of military history is that each new weapon has been 

met with countermeasures. It is likely that the development of directed energy weapons will be governed by that same law. For example, ablative 

coatings and RF hardening may reduce the vulnerability of conventional 

weapons to the effects of lasers and microwave devices, respectively. While 

some degree of RF hardening could be accomplished with minimal penalties, the trend in modern microprocessor electronics is to build the most 

economical and efficient devices, but these are also the most vulnerable.147 

Those charged with designing modern naval weapons will be confronted 

with the classic choice between survivability and efficiency. 

Similarly, anti-laser measures, including the use of ablative coatings on 

missiles, increase the weight and hence drag of the missiles, while reflective 

surfaces tend to increase the electro-optical signature, and thereby simplify 

the ability of the defender to detect missiles. There are detection systems 

that will warn an aircraft that it is being illuminating by a laser, but it is difficult to detect a narrowly focused beam from a laser weapon at short 

ranges. 

Eventually, other nations will field weapons that operate at the speed of 

light. As with nuclear weapons, directed energy systems will favor those 

who initiate the attack. The large apertures that give lasers high power and 

directional control have the greatest inherent vulnerability to attack. There 

will be pressure on the belligerent to fire the first salvo in order to blind the 

opponent.148 A less sophisticated opponent might choose to blind directed 

energy systems with the electromagnetic pulse of a nuclear detonation, but 

this action would cross the nuclear threshold and run the risk of nuclear war. 

A more likely scenario would be the employment of explosively driven RF 

munitions to blind the sensors associated with high-energy laser and RF 

systems. However, the relatively short ranges of ultra-wideband sources 

suggest that an attacker must use some type of delivery system. The implication is that tactical aircraft, unmanned air vehicles, or missiles that are 

used as delivery systems would be subject to attack by the very systems that 

they are intended to destroy. The defender, using directional antennas, enjoys a physical advantage over an attacker that uses an explosively driven 

source to radiate energy in a near spherical pattern. The reason is that the 

focused beam of a large aperture system delivers maximum power with 

minimal energy losses. The defender’s advantage may be strengthened by 
52 . . . Directed Energy and Fleet Defense 

the development of more sophisticated modulation schemes that extend the 

engagement ranges by enhancing the disruptive effects attained at lower radiated powers.149 

As with most weapon systems, the advantage is likely to shift successively from the attacker to the defender, and back again, as directed energy 

weapons experience technological and operational advances. Regardless of 

whether the United States develops these capabilities, it is likely that other 

states will perfect weapons that are ideally suited for the disruption and destruction of the information systems upon which modern naval forces depend. As the information centric concept of military operations gains ascendancy in military thinking, it will create a disproportionately greater vulnerability to attack from directed energy weapons.150 

Understanding Potential Anti-Satellite Applications 

The introduction of directed energy weapons into naval forces raises the 

question of whether these systems could be designed for anti-satellite operations. While there are significant technical differences between antisatellite and anti-cruise missile systems, the development of a dual-use system is feasible.151 For example, the potential role of the MIRACL laser as a 

anti-satellite weapon sparked serious congressional concerns, and led the 

United States Senate to block any MIRACL testing that could be construed 

as an anti-satellite capability.

152 

While the ability to blind space-based sensors would have great tactical 

utility, the political and legal implications of deploying such system are unanswered. It is inevitable that the use of a sea-based anti-satellite system 

would be perceived as a strategic threat to other states, including Russia and 

China. The ability to neutralize enemy or third party space-based sensors 

would greatly enhance the survivability of U.S. naval forces and could 

prove particularly useful in protecting theater missile defense units. A 

blinded opponent would be forced to rely on ships, aircraft, and unmanned 

air vehicles, all of which are vulnerable to conventional defenses. It must be 

understood that any tactical advantage gained by having anti-satellite capabilities on naval forces would quickly disappear if the enemy responded 

with a strategic attack against the United States because it faced the prospect 

of losing the space-based sensors upon which its ballistic missile force depends. 

The future offers more tantalizing possibilities. Sea-based lasers could be 

integrated into a system with space-based mirrors to provide a widely dis-
Directed Energy and Fleet Defense . . .53 

persed, survivable means for preventing states from gaining access to space. 

This development would define sea-based lasers as a strategic system, and 

thus raise the question of whether adversaries will field space-based laser 

systems that are capable of attacking the sensors and communications systems upon which U.S. military forces depend. 

The choice of fielding laser anti-satellite weapons is likely to be made by 

other states. For example, the Department of Defense’s annual report to 

Congress on the Chinese military declared that the People’s Republic “may 

possess the capability to damage, under specific conditions, optical sensors 

on satellites that are very vulnerable to lasers.”153 This capability is consistent with China’s development of lasers for military applications. It is a fact 

that the physics tend to favor ground or sea-based systems with large apertures and virtually unlimited power sources. From a technical perspective, a 

tactical shipboard laser system would enable the United States to preserve 

the option of fielding a robust, mobile anti-satellite capability. The political 

question, however, remains subject to debate. 
54 . . . Directed Energy and Fleet Defense 

VII. Conclusions 

This study examined the implications of directed energy systems for fleet 

defense in twenty-first century naval warfare. The United States is likely to 

remain committed to a national military strategy that embraces naval expeditionary warfare as a major component of its military capabilities. However, the ability to project naval power ashore will be increasingly difficult 

as potential adversaries gain access to sophisticated, low-cost weapons. 

Drawing from the experiences of the Second World War and competition 

with the Soviet fleet during the Cold War, U.S. Navy remains an expeditionary force that is centered on the carrier battle group and its associated 

amphibious ready group. Current technological and tactical trends are oriented toward the concept of defense in depth. The implication is that when 

confronted with overwhelming U.S. naval superiority, most adversaries will 

not run the risk of defeat in battle by directly challenging a major naval 

power, but will instead seek to make the cost of sea control as prohibitively 

expensive as possible. With the development of advanced cruise missiles 

that will pose an economical and widely available weapon for most opponents that seek to attack a major naval power on an asymmetric basis, the 

U.S. Navy must develop new defensive systems and new approaches to battle group operations. 

This study began with an examination of the current status of directed 

energy technology, and noted that there has been significant progress in 

both high-energy lasers and ultra-wideband microwave systems over the last 

decade. It is likely that these technologies will continue to be developed for 

military applications. The inherent advantages of weapons that travel at the 

speed of light and possess a virtually unlimited magazine are obvious. On 

the other hand, both laser and microwave technologies have fundamental 

physical limitations that limit their utility as autonomous weapon systems. 

For the foreseeable future, laser systems will be vulnerable to environmental 

degradation, while the range of microwave systems will be limited because 

of the atmospheric breakdown that occurs at higher power levels. 

Among the microwave technologies examined, ultra-wideband systems 

are best suited to defensive applications when one considers the inherent 

difficulties of hardening missiles across a broad frequency band. The range 

advantages of narrow band, high-power microwave systems are overshadowed by the need for prior knowledge about the target and the ability of the 

adversary to protect this weapon.

154 While it is too early to identify the best 
Directed Energy and Fleet Defense . . .55 

candidate for the high-energy laser system, this study used the Mid-Infrared 

Advanced Chemical Laser (MIRACL) as a basis for discussion because it 

represents a technology that can be fielded with some degree of confidence. 

Current development efforts in the areas as dispersion-less antennas and diode-pumped solid state lasers probably will further enhance the military effectiveness of directed energy systems. 

This assessment of the current technology suggests that the operational 

deployment of directed energy systems in the 2020-2025 timeframe is both 

feasible and prudent. Two Nimitz class nuclear powered aircraft carriers, 

John C. Stennis and Harry S. Truman, will require upgrades to their defensive suites, in conjunction with the mid-life re-fueling that is scheduled for 

the second decade of the next century. The timing of these events provides a 

window of opportunity for integrating directed energy systems into the carrier force. With the physical size and the margin of power available on nuclear-powered aircraft carriers, these naval vessels are well suited to accommodate the directed energy systems that are likely to be available. 

This study examined four possible configurations for integrating directed 

energy systems into aircraft carriers. The first two included the replacement 

of the carrier’s existing NATO Seasparrow and Mark 15 Close in Weapons 

Systems with either an ultra-wideband microwave system or a high-energy 

laser. The third alternative combines laser and microwave systems. The 

fourth option, which this study finds most preferable, involves a combination of ultra-wideband microwave systems with a set of high-energy lasers 

and three Rolling Airframe Missile systems. 

This composite suite is advantageous because it offers a robust selfdefense capability that exploits the operational synergies of these systems. 

The addition of “speed of light” weapons gives the defender with the ability 

to break the vicious cycle of ever-faster missiles. These directed energy 

systems would also provide a number of non-lethal options for self-defense. 

Freed from the need for a layered defensive screen of ships, the nuclear 

powered carrier, operating in tandem with a nuclear powered submarine, 

could exploit its inherent speed and self-sufficiency to deny its adversaries 

an opportunity for conducting asymmetric attacks. By dispersing the battle 

group, each platform could choose the optimum location for its primary 

mission of launching cruise missiles, defending against theater missiles, 

protecting commerce, or maritime interdiction. This flexibility will become 

increasingly important as the Navy moves to a smaller and more capable 

force that operates in the littoral region close to the shore. 
56 . . . Directed Energy and Fleet Defense 

The development of sea-based high-energy lasers raises the possibility of 

a strategic anti-satellite capability. While there are significant political issues to be resolved, there is evidence that other nations are developing 

equivalent capabilities today. As long as the United States possesses the 

most information dependent military force in the world, it will be vulnerable 

to states that use directed energy to disrupt or destroy its information dominance. The failure to develop and field directed energy systems could 

weaken the ability of the U.S. Navy to provide the naval presence and military power upon which the United States has depended throughout its history. 

Recommendations 

This study concludes with several recommendations for the U.S. defense 

establishment as it considers the role of directed energy weapons in its 

military forces. 

First, it is essential for the United States to conduct a detailed study of 

the critical milestones that affect the incorporation of directed energy systems into Nimitz class nuclear-powered aircraft carriers. By doing so, the 

U.S. Navy and the Department of Defense would have the opportunity to 

identify the critical technological constraints that will affect the development of this weapon. Officials in the defense establishment are well aware 

that the technology developed during the next ten years will define the systems that will be available for the first half of the next century. 

Second, it is equally essential for the United States to continue its current 

efforts to develop both microwave and laser systems. If the United States is 

to maximize the benefits of implementing directed energy technology, it is 

likely that defensive suites for aircraft carriers will rely on directed energy 

weapons and conventional missiles. Both will be necessary to permit the 

carrier to operate without escorts. To meet that objective, a suite that includes ultra-wideband microwave systems, high-energy lasers, and an advanced surface to air missile system will have significant operational advantages. 

Third, it is essential for the U.S. Navy to collaborate with technological 

programs being conducted by the other military departments, including the 

Air Force’s Airborne Laser and the Army’s Tactical High-energy Laser. 

This collaboration will help to resolve issues of common concern, including 

questions about the thermal blooming of laser energy, the sensitivity of la-
Directed Energy and Fleet Defense . . .57 

sers to weather conditions, and techniques for overcoming the atmospheric 

breakdown that occurs with high power microwave transmissions. 

Finally, in an era of constrained resources, the Navy must seek the best 

ways to use the nation’s technological strengths to ensure that U.S. expeditionary forces are capable of meeting the threats that will emerge in the 

twenty-first century. The broad strategic conclusion of this study is that directed energy weapons are among those critical technologies that will help 

the U.S. Navy defend the vital interests of the United States on the oceans of 

the world. 
58 . . . Directed Energy and Fleet Defense 

Notes 

1. For a discussion of contemporary views on the implications of the information 

dominated environment, see Joseph S. Nye and William A. Owens, “America’s Information Edge,” Foreign Affairs, Vol. 75, No. 2, March/April 1996, 20-36. See also Department of the Air Force, Cornerstones of Information Warfare, 1997, May 9, 1999, 

http://www.af.mil/lib/corner.html. 

2. USAF Scientific Advisory Board, New World Vistas: Air and Space Power for 

the 21st Century, Directed Energy Volume (Washington, DC: USAF Scientific Advisory Board, September 1996). 

3. Naval Studies Board, National Research Council, Technology for the United 

States Navy and Marine Corps, 2000-2035Becoming a 21st Century Force (Washington, DC: National Academy Press, 1997), pp. 183-187. 

4. The American Physical Society cited the uncertainty and differences of opinion 

surrounding the potential effectiveness of directed energy weapons when it established 

a study group in 1983. The group’s report, published in April 1987, documents many of 

the unexpected challenges that confronted technologists who attempted to develop operational laser systems. See Science and Technology of Directed Energy Weapons, Report of the American Physical Society (New York, NY: American Physical Society, 

April 1987), pp. 53-129. The history of the U.S. Air Force’s efforts to develop laser 

weapon systems is ably described in Robert W. Duffner, Airborne Laser: Bullets of 

Light (New York, NY: Plenum Press, 1997), pp. 5-93. Other service attempts as well as 

a West German effort are described in Major General Bengt Anderberg and Myron L. 

Wolbarsht, Laser Weapons: The Dawn of a New Military Age (New York, NY: Plenum 

Press, 1992), pp. 121-136. 

5. A more appropriate model for the adaptation of lasers might well have been the 

evolution of Robert Goddard’s fledging rockets of the 1920’s into the ICBM’s of the 

1950’s. It took a full thirty years for rocket technology to mature, notwithstanding substantial investments by both sides during World War II. 

6. US General Accounting Office Report, Navy’s Aircraft Carrier Program: Investment Strategy Options, GAO/NSIAD-95-17, August 27, 1998, 

http://www.fas.org/man/gao/gao9517.htm. 

7. Captain Wayne P. Hughes, Jr. USN, Ret., Fleet Tactics (Annapolis, MD: Naval 

Institute Press, 1986), p. 205. For a full discussion of the challenges faced by Admiral 

Sims, see Elting E. Morison, Admiral Sims and the Modern American Navy (Boston, 

MA: Houghton Mifflin Co. 1942), pp. 106-147. 

8. Bernard Brodie, Seapower in the Machine Age (1969; reprint, Princeton, NJ: 

Princeton University Press, 1943), p. 438. Brodie traces this caution back to historical 

figures such as Sir Robert Peel and Samuel Johnson. Furthermore, In this spirit, one 

does well to remember Captain Wayne Hughes’ caution: “Usually more than one piece 
Directed Energy and Fleet Defense . . .59 

of technology is required to create a revolution. Sail and canon together replaced the 

oared galley. Steam power alone was not enough to replace the ship of the line. It took 

the steam engine, the screw propeller, and the metal hull all together, which in turn 

made possible the big gun and the marriage of rifling, breech loading, and an effective 

fire control system . . . Great transitions require the engineering insight to fuse several 

scientific potentialities into a dramatically different weapon or sensor, the tactical insight to see how the weapon will change the face of battle, and the executive leadership 

to pluck the flower of opportunity from the thorns of government. The inspiration for 

these transitions often come from outside a navy. The perspiration always comes from 

within it.” See Hughes, pp. 221 and 215. 

9. See inter alia, Bill Hillaby, “Directed Energy Weapons Development and Potential” National Network News, July 1997, August 12, 1998, http://www.sfu.ca/dann/nn4-

3_12.htm; Department of the Navy, Challenges to Naval Expeditionary Warfare 

(Washington, D.C.: Office of Naval Intelligence, March 1997), p. 15. 

10. Department of the Navy, Forward . . . From the Sea, March 1997, July 10, 

1998, http:www.chinfo.navy.mil/palib/policy/fromsea/ffseanoc.html. 

11. Joint Pub 1-02, DOD Dictionary, December 1997, p. 172. 

12. ADM Jay L. Johnson, USN, “Forward . . . From the Sea, The Navy Operational 

Concept,” March 1997, http://www.chinfo.navy.mil/navpalib/policy/fromsea/ffseanoc. 

html. 

13. Joint Vision 2010, p. 4. 

14. Challenges to Naval Expeditionary Warfare, p. 6. 

15. Headquarters, U.S. Marine Corps, Concepts and Issues ’98, “Building a Corps 

for the 21st Century” (Washington, DC: 1998), pp. 32-33. 

16. National Research Council, The Navy and Marine Corps in Regional Conflict in 

the 21st Century (Washington, D.C.: National Academy Press, 1996), pp. 35-36. 

17. Department of the Navy, Vision-Presence-Power A Program Guide for the U.S. 

Navy, 1998 edition (Washington, DC: Office of the Chief of Naval Operations, May 

1998), pp. 60-61. To meet this challenge, the Navy must develop the “doctrine and tactics that make sense in a new strategic environment, and . . . fund the necessary force 

structure that gives the naval expeditionary forces the most decisive impact for the least 

cost and at minimum risk, and thereby ensure operational primacy is sustained.” See 

Vision-Presence-Power, p. 43. 

18. The term “cruise missiles” is describes a category of air, surface or sub-surface 

launched unmanned air vehicles that rely upon relatively sophisticated guidance systems and sustained propulsion systems to reach their targets. The propulsion systems 

include turbofan, turbojet, rocket and ramjet propulsion systems with speeds ranging 

from high subsonic to supersonic. However, the distinction between cruise missiles and 

remotely piloted vehicles is growing increasingly less clear. See David J. Nicholls, 
60 . . . Directed Energy and Fleet Defense 

Cruise Missiles and Modern War: Strategic and Technological Implications (Maxwell 

AFB, AL: Center for Strategy and Technology, Occasional Paper No. 13) forthcoming. 

19. The following summarizes the known producers and exporters of cruise missiles: 

Cruise Missile Producers and Exporters 

Argentina India (poss. exports) Japan Sweden (exports)

Brazil Iran N. Korea (exports) Taiwan

China (exports) Iraq Norway (exports) U.K. (exports)

France (exports) Israel (exports) Russia (exports) U.S. (exports)

Germany Italy (exports) S. Africa (exports)

Note: Indonesia, Singapore, and Ukraine are also assessed to have the aerospace industrial capacity to produce cruise missiles. See “Cruise Missile Capabilities and Suppliers,” Centre for Defence and International Security Studies, October 8, 1998, 

http://www.cdiss.org/tabanaly.htm. 

20. Ibid. 

21. “Challenges to Expeditionary Naval Warfare,” pp. 12-13. 

22. “Missile Capabilities by Country,” Centre for Defence and International Security Studies, October 8, 1998, http://www.cdiss.org/tablef.htm. 

23. “Cruise Missiles and WMD,” Centre for Defence and International Security 

Studies, October 8, 1998, http://www.cdiss.org/cbwcm.htm. 

24. “Selected RPV Capabilities,” Centre for Defence and International Security 

Studies, October 8, 1998, http://www.cdiss.org/tablef.htm. 

25. “Ballistic Missiles and WMD,” Centre for Defence and International Security 

Studies, Internet, October 8, 1998, http://www.ediss.org/cbwbml.htm. 

26. “Challenges to Expeditionary Naval Warfare,” pp. 16-17. 

27. “Ballistic Missiles and WMD,” and “The Devil’s Brews: An Introduction,” 

Centre for Defence and International Security Studies, October 8, 1998, 

http://www.cdiss.org/cbwintro.htm. 

28. Department of Defense, Persian Gulf War Study (Washington, DC: 1992). 

29. General Sir Peter de la Billiere, Storm CommandA Personal Account of the 

Gulf War (London, UK: Harpers Collins Publishers, 1992), p. 148. 

30. “Challenges to Expeditionary Naval Warfare,” pp. 8-11. 

31. “Challenges to Expeditionary Naval Warfare,” pp. 22-23. 

32. Lieutenant Commander J. Todd Black, U.S. Navy, “Commercial SatellitesFuture Threats or Allies?” Naval War College Review, Winter 1999, November 19, 

1998, http://www.nwc.navy.mil/press/Review/1999/winter/art5-w99.htm. 
Directed Energy and Fleet Defense . . .61 

33. See Statement of Ira W. Merritt, Chief Concepts Identification and Applications 

Analysis Division, U.S. Army Space and Missile Defense Command, in “Proliferation 

and Significance of Radio Frequency Weapons Technology,” Testimony before the 

Joint Economic Committee, U.S. Congress (Washington, D.C.: February 25, 1998) 

August 27, 1998, http://www.fas.org/irp/congress/1998_hr/s980225m.htm. 

34. In other testimony before the committee, it was pointed out that an Australian 

professor, formerly associated with the Royal Australian Air Force, operates a personal 

web site that provides the basic guidelines for weaponizing a transient electromagnetic 

device. See Statement of Mr. David Schriner, Chief Scientist, Directed Energy Technologies, Schriner Engineering, in “The Design and Fabrication of a Damage Inflicting 

RF Weapon by “Back Yard” Methods,” Testimony before the Joint Economic Committee, U.S. Congress (Washington, D.C. February 25, 1998) August 27, 1998, 

http://www.fas.org/irp/congress/1998_hr/s980225ds.htm. 

35.Carlo Kopp, “The E-Bomba Weapon of Electrical Mass Destruction,” 

Infowar.com and Interpact, Inc., October 9, 1998, http://www.infowar.com/mil_c4i/ 

mil_c4i8.html-ssi. 

36. Hillaby, “Directed Energy Weapons Development and Potential.” 

37. In 1995, North China Industries Corporation offered the ZM-87 anti-personnel 

weapon for sale, which is capable of causing flash blindness at ranges up to 10 km and 

permanent blindness at ranges of 2-3 km. See “Challenges to Expeditionary Naval Warfare,” 15. 

38. “Challenges to Expeditionary Naval Warfare,” p. 15. 

39. Los Angeles Times, November 28, 1998, quoted in AFSPC Legislative Liaison, 

December 10, 1998. 

40. Ji Shifan, Development of Tactical Air Defense Laser Weapons at Home and 

Abroad: An Outline, trans. Leo Kanner Associates (Wright-Patterson Air Force Base, 

OH: National Air Intelligence Center, 1996), pp. 10-15. 

41. H. H. Arnold and Ira C. Eaker, This Flying Game (New York, NY, 1938), pp. 

130, 135-139. 

42. New York Times, October 12, 1945, p. 1. and Bernard Brodie, “The Atomic 

Bomb and American Security,” Institute for International Studies Memorandum No. 18 

(New Haven, CT: Yale Institute for International Studies, November 1, 1945), p. 6. 

43. Jeff Hecht, The Laser Guidebook (New York, NY: McGraw-Hill, Inc. 1992), p. 

16. 

44. Robert W. Duffner, Airborne Laser: Bullets of Light (New York, NY: Plenum 

Press, 1997), pp. 1-15. 

45. Electromagnetic radiation is emitted when an electron transitions from a higher 

energy state to a lower energy state. A common example is the fluorescent light. It can 

also occur when there are changes in the rotational or vibrational states of molecules. In 
62 . . . Directed Energy and Fleet Defense 

quantum mechanics the smallest packet of light energy as a photon whose energy is 

determined by the difference between the initial and final energy levels. Planck’s constant relates the frequency of the light to the energy of the photon: 

E=h x v 

This, in turn, describes the wavelength of the light emitted. Emissions range from Xrays through the optical region into the infrared portion of the spectrum. When energy 

is added to the atoms in the lazed material, many of the electrons are excited to a higher 

energy level. Because it is an inherently unstable condition, the electrons will eventually fall back to lower energy states, or “decay.” This occurs spontaneously, which results in the emission of randomly directed photons. Rather than returning to their 

ground states, electrons often decay to an intermediate energy level, a meta-stable state, 

where they may remain for microseconds. This phenomenon of electrons occupying 

higher energy levels is known as population inversion. A chain reaction can develop as 

photon emission is stimulated by collisions with other photons. This process results in 

release of photons travelling in the same direction, in phase, at the same wavelength. 

See Robert Aldrich, “Laser Fundamentals,” NSWC, Dahlgren Division, August 27, 

1998,: http://www.fas.org/man/dod-101/navy/docs/laser/fundamentals.htm. 

46. Major General Bengt Anderberg and Myron L. Wolbarsht, Laser Weapons: The 

Dawn of a New Military Age (New York, NY: Plenum Press, 1992), pp. 11-42. 

47. Richard Saunders, et al., Lasers Operation, Equipment, Application, and Design 

(New York, NY. McGraw-Hill Book Company, 1980), p. 10. For reference, The lower 

limit on the divergence (or spreading) of a laser beam is a function of the wavelength of 

the light and the size of the aperture. And divergence can be reduced by either shifting 

to shorter wavelengths (higher frequencies) or increasing the size of the aperture. Lasers whose divergence is reduced to the theoretical minimum are categorized as diffraction limited. 

48. The causes of broadening include nearly adjacent transition energy levels, doppler broadening in gas lasers, and lattice vibrations in solid lasers. 

49. Hecht, pp. 23-47, 263-272. 

50. Hecht, p. 97. 

51. USAF Scientific Advisory Board, pp. 32-33. 

52. USAF Scientific Advisory Board, pp. 34-35, 49-51. 

53. USAF Scientific Advisory Board, pp. 66-67. 

54. In a device similar to a rocket engine, ethylene (C2H4) is combined with an oxidizer, nitrogen trifluoride (NF3) and excited fluorine atoms are released as a product of 

combustion. Molecular hydrogen or deuterium is then injected with the atomic fluorine 

to produce an excited halide. See John Pike, “Mid-Infrared Advanced Chemical Laser 

(MIRACL),” FAS Space Policy Project, March 21, 1998, 1-4; August 27, 1998, 

http://www.fas.org/spp/military/program/asat/miracl.htm. 
Directed Energy and Fleet Defense . . .63 

55. “Nautilus - Lasers are Lethal,” U.S. Army Space and Missile Defense Command, October 3l, 1998, http://www.smdc.army.mil/NAUT.HTML. “Tactical High 

Energy Laser (THEL),” U.S. Army Space and Missile Defense Command, October 31, 

1998, http://www.smdc.army.mil/THEL.HTML. Additional information is available 

from TRW Inc. at http://www.trw.com. 

56. Pike, pp. 3-4. 

57. Pike, pp. 3-4. A “contingency anti-satellite operational capability” was established in 1990. However, public disclosure came almost seven years later. See Joung R. 

Cook, “US Navy HEL Weapons Fundamental Issues,” Address to the First Directed 

Energy Symposium, Kirtland AFB, NM, November 6, 1998. A discussion of the politics associated with the MIRACL system’s potential as an anti-satellite weapon can be 

found in Inside the Army, November 30, 1998, slides 13-17. 

58. Cook, slides 5-7. 

59. For reference, the COIL uses a process that transfers energy from excited oxygen molecules to iodine atoms, and by using iodine atoms for the laser output, produces 

a wavelength of 1.3 microns. 

60. US General Accounting Office Report, Theater Missile Defense: Significant 

Challenges Face the Airborne Laser Program, GAO/NSIAD-98-37, August 27, 1998, 

http://www.fas.org/spp/starwars/gao/nsiad98037.htm. 

61. USAF Scientific Advisory Board, pp. 38-40. 

62. Anderberg and Wolbarsht, pp. 38-39. 

63. The term “ubitron” is derived from undulated beam interaction, which describes 

how the device uses a periodic transverse magnetic field known as a “wiggler” to cause 

a ponderomotive (beat) wave to develop. The period of the magnetic wiggler is then 

adjusted to produce a resonance between the beam and the ponderomotive wave. See 

“High Power Coaxial Ubitron Oscillator,” DoD Multidisciplinary University Research 

Initiative, October 31, 1998, http://tempest.ece.ucdavis.edu/muri/western/ucd/adam/ 

coaxosec.html. 

64. Naval Studies Board, pp. 184-185. 

65. Alternatives include passive wavefront correction using non-degenerate four 

wave mixing or stimulated thermal scattering for non-linear wavefront correction. 

66. USAF Scientific Advisory Board, pp. 4-5, 40-47, 63-69. 

67. Duffner, 239-253 and 271-305. The complexities of developing an effective 

tracking scheme are well documented in the history of the ALL. 

68. Cook, slide 5. 

69. The distribution of energy is caused by the Heisenberg uncertainty principle, 

molecular collisions, electric fields, magnetic fields, and Brownian motion. 
64 . . . Directed Energy and Fleet Defense 

70. Joseph S. Accetta and David L. Schumaker, eds., The Infrared and ElectroOptical Systems Handbook, vol. 2, Atmospheric Propagation of Radiation (Ann Arbor, 

MI: Environmental Research Institute of Michigan, 1993), pp. 3-64. While this text is 

the successor to The Infrared Handbook, chapters 4, 5, and 6 of the 1985 revised edition of the latter contains a wealth of empirical data on atmospheric absorption, scattering and propagation. The new text provides reference to both the HITRAN and 

LOWTRAN databases; however; it lacks some of the easily inspected graphs of the 

former. See William L. Wolfe and George J. Zissis, The Infrared Handbook, rev. ed. 

(Washington, DC: Office of Naval Research by the Infrared Information and Analysis 

Center, Environmental Research Institute of Michigan, 1985). 

71. For example, carbon dioxide typically shows a seasonal variation, with maximum levels observed in early spring and minimum levels reached in late summer and 

fall. 

72. The “clear blue sky” one observes overhead is due to molecular Rayleigh scattering, while the whitish gray haze observed at the horizon is due to aerosol effects. The 

haze may be caused by smoke, dust, or clouds. There is an overlap of effects when 

clouds, fog or smog form a portion of the haze. See Accetia and Schumaker, pp. 11-12, 

100-112. 

73. Accetta and Schumaker, pp. 11-12, 100-112. 

74. Because convection heating typically dominates this phenomenon, a circular 

beam will generally be distorted into a non-symmetrical crescent shaped pattern that 

spreads transversely to the wind direction. See Accetta and Schumaker, pp. 290-297. 

75. Samuel Glasstone, ed., The Effects of Nuclear Weapons, Air Force Pamphlet 

(AFP 136-1-3) (Washington, DC: Department of the Air Force, April 1962), and Samuel Glasstone and Philip J. Dolan, ed., The Effects of Nuclear Weapons (Washington, 

DC: Department of Defense and Department of Energy, 1977). 

76. There was a simultaneous failure of 30 series of connected loops of streetlights 

on the island of Oahu. While the effects were little more than an annoyance, this event 

served to warn the United States military of the widespread secondary effects of electromagnetic pulses. 

77. Glasstone and Dolan, pp. 514-529. 

78. Merritt, pp. 1-2. 

79. The effects of HPM devices can be categorized as follows: “Upset”a temporary alteration of the electrical state of one ore more components, precluding normal 

operation until the radiation is terminated; “Lock-up”a temporary alteration, as 

above, however, an electrical reset is necessary to restore normal operation after the 

radiation is terminated; “Latch-up”an extreme form of lock-up that can result in either circuit destruction or pull down of power supply voltages; “Damage”electrical 

destruction by a mechanism such as latch-up, metallization burn out or junction burn 

out. Since certain forms involve charge build-ups that decay over time, permanent dam-
Directed Energy and Fleet Defense . . .65 

age or electrical burn out is sometimes used to distinguish from the less permanent effects. See David M. Sowders, et al., High Power Microwave (HPM) and Ultrawideband (UWB): A Primer on High Power RF, PL-TR-95-1111 (Kirtland AFB, NM: 

Air Force Material Command, 1995), pp. 81-84. 

80. Semi-conductor devices will fail when exposed to voltages that exceed the dielectric strength of the component, or when RF induced current heats one of its subcomponents to its melting point. As Kopp points out, the trend towards equipment vulnerability is increasing. Voltage ratings for silicon bi-polar transistors typically vary 

from 15V-65V. Gallium Arsenide FETs are typically rated at about 10V. Dynamic 

Random Access Memories are typically rated at about 7V. Microprocessors are often 

rated even closer to their operating voltages of 3.3V to 5V. 

81. Merritt, pp. 3-5. 

82. Chemical explosives have energy densities on the order of 8kJ/cc. Present technology limits high-energy density capacitors to approximately 1J/cc. 

83. The losses associated with the conversion of chemical energy into an explosion 

and the conversion of the magnetic energy into electrical energy could be avoided. As 

previously noted, explosive reactions represent a quite inefficient means of transferring 

energy. 

84. Merritt, pp. 4-6. While there have been questions raised with regard to the reproducibility of some of the Russian claims. See L. L. Altgilbers, I. Merritt, M. Brown, 

J. Henderson, D. Holder, and Merriweather, OCONUS Radio Frequency Munitions Test 

Report, ATD-98-001, December 4, 1997. It is evident, from other systems that have 

been exported to the West, that Russian and other FSU laboratories continue to make 

major strides in this area. 

85. In addition to switch limitations, the characteristic mismatch between the output 

impedance of inductive storage devices (1-10 ohms) and the high power RF systems 

operating typically between 10-100 ohms limits their efficiency. For capacitive systems, better dielectric materials are required so that less heat is developed during the 

charge/discharge process. 

86. This includes the relativistic magnetron, an outgrowth of radar development; the 

large orbit gyrotron, a form of electron cyclotron maser; the relativistic klystron, which 

traces its origins to radar and weapons development; and the vircator, a relatively new 

and elegant design, that is commonly used in single pulse applications. 

87. Schriner, p. 5. 

88. The spark gap switch operates on the principle of creating an electrical breakdown within a dielectric material when the voltage reaches a set value. The high voltage stress placed on the dielectric material will form spark channels, which permits the 

current to flow. The violent breakdown process leaves debris in the current channels, 

which must be cleared prior to firing the switch again. Phillip’s Laboratory has made 

significance progress in this area using gas switches that have demonstrated repetition 

rates of up to 1 kHz. See Sowders, et al., p. 46. 
66 . . . Directed Energy and Fleet Defense 

89. However, the penalty for a constant amplitude and phase response across a wide 

frequency range is a much lower gain than traditional narrowband antennas, which significantly limits the effective radiated power that could be achieved. 

90. USAF Scientific Advisory Board, pp. 58-60. For an alternative view, see the 

U.S. Army forecast of Electronic Warfare/Directed Energy Weapons, http://mrmcwww.army.mil/mrmclibrary/astmp/original/original/c4/P4K.htm. The Army projection 

is that high average power travelling wave tubes and advanced RF weapons will be 

available by the year 2003. And by the year 2012, advanced conventional source systems and alternate source weapon systems are seen to be likely. 

91. Naval Studies Board, 184-187, pp. 195-203. 

92. USAF Scientific Advisory Board, pp. 27-29, 35-35. 

93. USAF Scientific Advisory Board, pp. 22-26, 32-42. 

94. Adapted from briefing material provided by Mr. Mike Diekhoff of a briefing 

given by Barry Hogge, Chief Scientist, Directed Energy Directorate, Phillips Research 

Site, “Assessment of the SAB Aerospace Expeditionary Force Studies Recommendations,” May 1, 1998. 

95. Naval Studies Board, pp. 202-203. 

96. Naval Studies Board, pp. 184-185. 

97. USAF Scientific Advisory Board, pp. 36-38, 67. 

98. Gen (ret) Ronald Fogelman, “Directed Energy-Applications in Tactical Airborne Combat, Phase One Results,” Address to the Directed Energy Symposium, Kirtland Air Force Base, NM, November 5, 1998. 

99. Even a signal originating from a highly directional antenna will spread as a 

square of the distance. 

100. Author interview, Patrick Vail, Air Force Research Laboratory, Phillips Research Site, November 6, 1998. 

101. These effects were described in note 79 above. A broader discussion is available in Sowder, et al. 

102. RF transmitting materials, such as epoxy/fiberglass, ceramic and fiberized ceramics, generally serve as good thermal insulators. Similarly, the material used for infrared seeker windows, such as gallium arsenide, quartz, diamonds, fiberized composites, are also generally thermally resistant. The destruction of the radome will likely 

dissipate much of the energy. See Cook, slide 11. 

103. The Mid-Infrared Advanced Chemical Laser (MIRACL) has successfully engaged five BQM-34 sub-sonic drones as well as a supersonic Vandal missile target. The 

Airborne Laser Laboratory enjoyed similar success against drones and AIM-9 missiles. 
Directed Energy and Fleet Defense . . .67 

More recently, the US-Israeli Nautilus Program used the MIRACL to successfully destroy a short-range rocket in-flight. While the flight parameters of the latter were substantially different from those encountered in the cruise missile regime, the destructive 

power of the laser was again demonstrated. See “Mid-Infrared Advanced Chemical 

Laser,” FAS Space Policy Project, March 21, 1998, August 27, 1998, 

http://www.fas.org/spp/military/program/asat/miracl.htm. “NautilusLasers Are Lethal,” U.S. Army Space and Missile Defense Command, October 1997, October 31, 

1998, http://www.smdc.army.mil/NAUT.HTML. “Tactical High Energy Laser (THEL) 

21st Century Air Defense,” U.S. Army Space and Missile Defense Command, October 

31, 1998, http://www.smdc.army.mil/THEL.HTML. 

104. See Cook, slide 11. 

105. The assumption is that the laser system employs a phased array of laser diodes 

which do need to be trained or elevated prior to engagement. In fact, tests with the Sea 

Lite Beam Director demonstrated that while capable of rapid engagements, there remains a finite amount of time needed to shift from one target to the next. See New 

World Vistas, p. 67. 

106. The SPS-48E is a three-dimensional air surveillance radar used as the primary 

organic sensor for the CVN’s combat systems suite. Current plans call for the integration of the SPS-48E with other elements of the ship’s anti-ship missile defense systems 

into a networked Ship’s Self-Defense System (SSDS). The limiting factor for data updates remains the mechanical rotation in azimuth of the electronically scanned array. 

While plans call for passive sensors to provide 360-degree coverage, electronic surveillance systems are dependent upon one’s opponent to radiate and electro-optical sensors are sensitive to environmental factors. See Martin Streetly, ed. Jane’s Radar and 

Electronic Warfare Systems 1997-1998 (London, UK: Jane’s Information Group, Ltd. 

1998), pp. 170-171. 

107. Military helicopters pose a slightly different problem. Since they are generally 

turbine powered, they may present a significant IR source, if IRCM are not employed. 

They also tend to produce a broad spectrum of Doppler returns due to radar reflections 

from the blades. Nevertheless, their relatively low speeds, combined with the absence 

of a strong Doppler return, makes them a challenging target for conventional defense 

systems. 

108. The Saratoga (CV 60) accidentally fired a salvo of two Seasparrow missiles at 

the Turkish destroyer, Mauvenet, on October 1, 1992. One of the two missiles, with a 

nominal 38-kg warhead, struck the ship. While the Mauvenet was not sunk, the bridge 

was destroyed and five crewmembers, including the captain, were killed. This damage 

equated to a “mission kill.” See “The Navy’s Year in Review,” U. S. Naval Institute 

Proceedings 119, No. 5 (May 1993), p. 125. 

109. “Facts and Figures,” Sea Power 41, No. 1 (January 1998), p. 198. 
68 . . . Directed Energy and Fleet Defense 

110. CVN’s typically employ a mix of 50 caliber machine guns and M-60’s to deliver harassing fire. Even the 25mm chain gun, employed on other high value units such 

as fast combat support ships, has a limited range and effectiveness. 

111. Without careful metallurgical inspection it may not be possible for an opponent 

to determine the reason for the hole in the waveguide. To the operator, the first symptom will likely be a system overload due to excessive reflected power. The potential 

subtleties of such an attack mechanism will make its incorporation into the rules of engagement challenging. Nor is it obvious whether this is more or less escalatory than 

active jamming. 

112. In 1990, the U.K. Ministry of Defense acknowledged that it had developed and 

fielded a laser dazzle system, manufactured by Irwin Desman Ltd., for use by the Royal 

Navy’s Broadsword frigates and Type-42 destroyers. Although reported deployed to the 

Arabian Gulf for anti-small boat defense, industry sources assess it as capable of deterring a kamikaze style air attack. The system reportedly uses a low-power blue laser that 

does not cause permanent eye injuries. At a nominal range of 2.75 kilometers, an UWB 

microwave system would not only appear to be more effective, it would also preclude 

any concerns with violations of Protocol IV to the United Nations Conventions on Prohibitions on Conventional Weapons. A. P. O’Leary, ed. Jane’s Electro-optic Systems 

1997-1998 (London, UK: Jane’s Information Group, Ltd. 1998), pp. 11, 31-31. 

113. The danger of fratricide in a counter-periscope mode would likely require that 

the laser weapon is controlled by an operator who makes the decision to engage. As 

competent submariners leave their periscopes exposed for only seconds, it is unlikely 

that there would be sufficient time for an operator to identify and engage a periscope 

target. 

114. Such actions against legitimate collection platforms would have to be consistent with international protocols that permit the observation and collection of missile 

launch telemetry data. 

115. Nimitz class CVN’s have undergone steady combat system upgrades throughout their service lives. Current plans call for the incorporation of the Advanced Combat 

Direction System Block 1, the Advanced Integrated Electronic Warfare System, the 

Cooperative Engagement Capability, and the Mark 1 Ship’s Self-Defense System. Department of the Navy, Vision, Presence, PowerA Program Guide to the U.S. Navy 

1998 Edition (Washington, DC: Chief of Naval Operations, May 1998), pp. 59, 70-90. 

116. Dennis J. Carroll, “Missile systems and naval operations 2010 and beyond,” 

Global Defence Review, November 24, 1998, http://www.global-defence.com. 

117. The Mark 15 Phalanx Close-in-Weapon System (CIWS) has a nominal weight 

of 13,600 pounds for the topside weapon assembly and an additional 725 pounds of 

below deck equipment. This equates to the weight and volume estimates for the Naval 

Research Laboratory’s design for a 100 kW class shipboard laser. See “Facts and Figures,” Sea Power 41, No. 1 (January 1998), p. 198. 
Directed Energy and Fleet Defense . . .69 

118. Nimitz, the first CVN programmed to receive the Rolling Airframe Missile 

system, is scheduled for upgrade during its current re-fueling overhaul. There are presently two variants of the RIM-116A, the Block 0, which relies on passive RF for midcourse guidance and passive IR for terminal homing, and the new Block 1, which incorporates an infrared image-scanning seeker that permits autonomous infrared tracking 

of a non-emitting target. See “Raytheon Awarded $28 Million for Rolling Airframe 

Missile Work,” Raytheon Press Release, June 23, 1998, December 11, 1998, 

http://www.seiscor.com/pres/1998/jun/ramcon.html. 

119. Each NATO Seasparrow Missile System (NSSMS) launcher assembly has a 

magazine of eight missiles. With three NSSMS launchers, the CVN can have up to 24 

missiles loaded. Re-load of the NSSMS launcher is a lengthy (1 hour plus) process. 

Designed to replace both the NSSMS and CIWS, the RAM has a 21 missile magazine 

launcher. Three RAM systems would provide an additional 39 missiles above the 24 

currently available in the three NSSMS magazine launchers. See Captain Richard 

Sharpe, OBE, RN, ed. Jane’s Fighting Ships 1997-1998 (London, UK: Jane’s Information Group, Ltd. 1998), p. 802. 

120. The configuration described is essentially the same as the Sea Lite Beam Director employed during its successful engagements. 

121. The Royal Navy’s experience in the Falkland’s conflict illustrated that the actual expenditures of weapons far exceeded the models used to analytically calculate 

what would be necessary to neutralize the threat. As the British White Paper on the 

Falklands emphasized, the “rates of usage, particularly of ammunition, missiles and 

anti-submarine weapons were higher than anticipated.” Cordesman and Wagner quoted 

the White Paper in The Lessons of Modern War, and went on to generalize the same 

conclusion for all conflicts discussed in the series (1973 Arab-Israeli War, Iran-Iraq 

War, Falklands and Afghan conflicts) with the exception of the mujahideen who never 

had sufficient resources. See The Falklands Campaign The Lessons (London UK: 

HMSO, December 1982), p. 25, and Anthony H. Cordesman and Abraham R. Wagner, 

The Lessons of Modern War, Vol. 3, The Afghan and Falklands Conflict (Boulder, CO: 

Westview Press, 1990), pp. 330, 366. 

122. Although there will probably be more missiles to re-load during any given 

evolution, the smaller size (9.2 ft vs. 12 ft) and the lighter weight (approximately one 

third the weight of the RIM-7) should facilitate the loading process. See Sea Power, pp. 

196, 198. Any steps that reduce the requirements for handling conventional weapons 

dramatically simplifies the defense when chemical or biological weapons have been 

employed. The re-loading of mechanical gun systems (i.e., Mark 15 CIWS) is particularly challenging for personnel who are attired in full protective gear. 

123. Adapted from Cook, slide 12. Data for UWB system developed from Sowders, 

et. al., and author interview with Patrick Vail, November 6, 1998. 

124. Hughes, Fleet Tactics, p. 109. 

125. Naval Warfare, p. 33. 
70 . . . Directed Energy and Fleet Defense 

126. While officially embracing the tenets of maneuver warfare as the superior form 

of naval warfare, NDP 1 acknowledges the historic role of the Battle of the Atlantic in 

World War II and other critical attrition warfare campaigns. Rather than attempting to 

force naval warfare into a template devised for land combat, Hughes argues that naval 

warfare is so distinct that it is best described as “power warfare.” His argument centers 

on the combatant units of naval forces and the typical outcomes of naval combat. Unlike actions ashore, classical naval combat results in the sinking or total elimination of 

the combat potential of one participant’s vessels. Crippled ships are typically not combat capable for months or years. The relatively small number of major combatants and 

the inherently high stakes of naval engagements result in a significantly different calculus for naval commanders. Captain Wayne P. Hughes, Jr. U.S. Navy (retired), “Naval 

Maneuver Warfare,” Naval War College Review, No. 3 (Summer 1997), p. 26. The next 

generation of shipboard weaponry, such as the French ASTER, the Evolved Seasparrow, 

and the Ship’s Self-Defense System, are all based upon the same principles of layered 

defense. See “Defence Power - Developments of the Decade,” Global Defence Review, 

http://www.global-defence.com; and Dennis J. Carroll, “Missile Systems and Naval 

Operations, 2010 and beyond.” 

127. Boyd is probably most famous for his observation, orientation, decision, and 

action (OODA) loop. Introduced in the mid-1970’s it resonated with many who sought 

a shift to a more dynamic form of warfare. His concepts closely paralleled those of J. S. 

Lawson of the Naval Postgraduate School who developed a similar feedback model of 

the command and control-cycle that included five steps, “sense, process, compare, decide and act.” Hughes expanded Lawson’s concept by positing two interlocking loops 

defining the principal adversaries. Hughes, Fleet Tactics, pp. 175-189. 

128. The parallels of land and sea warfare were articulated by T. E. Lawrence, the 

practitioner of unconventional desert warfare, who wrote, “In character our operations 

of development for the final stroke should be like naval warfare, in mobility, ubiquity, 

independence of bases and communications, ignoring of ground features, of strategic 

areas, of fixed directions, of fixed points.” See T. E. Lawrence, Seven Pillars of Wisdom: A Triumph (Garden City, NY. Doubleday, 1935), p. 337. 

129. Boyd’s message can be summarized in his statement, “He who is willing and 

able to take the initiative to exploit variety, rapidity, and harmony - as basis to create as 

well as adapt to the more indistinct - more irregular - quicker changes of rhythm and 

pattern, yet shape focus and direction of effort - survives and dominates - or contrariwise - He who is unwilling or unable to take the initiative to exploit variety, rapidity, 

and harmony . . . goes under or survives to be dominated.” See John R. Boyd, “A Discourse on Winning and Losing” (Briefing materials, August 1987), p. 174. 

130. The traditional Mahanian view was to mass the fleet in order to confront and 

destroy the opposing force and establish command of the sea. For Mahan, this conviction was so deeply held that he saw no justification in dividing the fleet. The depth of 

his conviction is reflected in his statement that if the Naval War College “had produced 

no other result than the profound realization by naval officers of the folly of dividing 

the battle-fleet, in peace or in war, it would by that alone have justified its existence and 
Directed Energy and Fleet Defense . . .71 

paid its expenses.” See Naval Strategy: Compared and Contrasted with the Principles 

and Practice of Military Operations on Land (Boston, MA: 1911), p. 6. Corbett took a 

more contemporary view, that by denying definitive combat, an opponent could continue to contest control of the seas in those areas where he might obtain a local superiority of forces. Corbett suggested that the contest for command of the sea might remain 

in dispute throughout a conflict. See Spenser Wilkinson, “Strategy in the Navy,” 

Morning Post (London), 3 August 1909, November 24, 1998, 

http:www.mnsinc.com/cbassfrd/cwzhome/histart/wilkl.html. 

131. During the early phase of the Solomon’s campaign, Japanese destroyers, operating at night, without the benefit of radar, devastated U.S. cruisers by simply firing 

spreads of torpedoes along their track. The U.S. navy learned the lesson well and eight 

months later, Commander Frederick Moosebruger used a similar plan, developed by 

Commander Arleigh Burke, to sink three of four Japanese destroyers at the Battle of 

Vella Gulf. Burke’s turn came in November 1943 when he had a similar success at the 

Battle of Cape Saint George. See E. B. Potter, Sea PowerA Naval History, Second 

Edition (Annapolis, MD: U.S. Naval Institute, 1981), p. 314. In 1917, the German Navy 

was able to demonstrate that small, relatively fast light craft were able to exploit the 

long nights at higher latitudes in order to destroy convoys and return safely to bases 500 

nautical miles distant. See Bernard Brodie, Sea Power in the Machine Age (1943, reprint, New York, NY: Greenwood Press, 1969), p. 94. 

132. Brodie, p. 94. 

133. In Fleet Tactics, Hughes quotes LCDR McKearney’s 1985 Naval Postgraduate 

School thesis which computed the overall probability of a torpedo hit by Japanese 

forces during the Solomon’s campaign as being 0.06 with occasional battles, such as, 

Tassafaronga, reaching as high as 0.20. See Lieutenant Commander T. J. McKearney, 

USN, “The Solomons Naval Campaign: A Paradigm for Surface Warships in Maritime 

Strategy,” Thesis, U.S. Naval Postgraduate School, Monterey, CA, 1985. In the example given, an attacker firing 16 SS-N-22 missiles would accomplish his mission if he 

could match the Japanese Navy’s 0.06 success rate. 

134. The term “fleet tactics” is taken from Captain Wayne P. Hughes’ classic work 

of the same name. Hughes defines fleet tactics as dealing “with operations involving 

coordination between multiple ships and aircraft.” He goes on to describe fleet tactics 

as the analog of grand tactics or operational art as the latter terms are used in land combat. 

135. During the Gulf War, the threat of amphibious operations was used as a diversion; however, the mine problem highlighted the need for alternatives with greater 

flexibility and less predictability. See General Sir Peter de la Billiere, Storm CommandA Personal Account of the Gulf War (London, UK: Harper Collins Publishers, 

1992), p. 148. 

136. See Concepts and Issues ’98Building A Corps for the 21st Century, pp. 21-

23. 
72 . . . Directed Energy and Fleet Defense 

137. The practical implications of Operational Maneuver From The Sea are wellarticulated in Lieutenant Mark W. Beddoes, USN, “Logistical Implications of Operational Maneuver from the Sea” Naval War College Review, Autumn 1997, November 19, 1998, http://www.nwc.navy.mil/press/Review/1997/autumn/art3-a97.htm. 

138. Hughes, Fleet Tactics, p. 250. 

139. The Royal Navy encountered this problem during the Falkland’s conflict when 

two Exocet missiles fired at HMS Ambuscade were successfully deflected. After passing through a chaff cloud, they acquired and struck the Atlantic Conveyor. See Admiral 

Sandy Woodward and Patrick Robinson, One Hundred Days (London, UK: Harper 

Collins, 1992), p. 295. 

140. The greater the distance from the enemy’s coast, the more time for the U.S. 

Navy to react. Only the major naval powers have vessels with the ability to operate at 

maximum speeds for extended periods and then to replenish without returning to port. 

The coastal patrol craft of many navies will be constrained by fuel if they undertake 

combat at distances of 100 nautical miles or more from a friendly port. Extended distances from land minimize the threats from land-based missiles and helicopters as well 

as that posed by tactical aviation. 

141. For an elaboration of this discussion see Lieutenant Commander Charles C. 

Swicker, USN, “Ballistic Missile Defense from the SeaThe Commander’s Perspective” Naval War College Review, Spring 1997, November 19, 1998, 

http://www.nwc.navy.mil/press/Review/1997/spring/art1sp97.htm. 

142. Geoffrey Till reminds readers of Sir Julian Corbett’s words, “This power of 

disturbing the enemy with feints is of course inherent in the peculiar attributes of combined operations: in minesweeping vessels, for instance, there is a new instrument . . . 

capable of creating a very strong impression at a small cost to the fleet. Should a flotilla 

of such craft appear at any practicable part of a threatened coast and make a show of 

clearing it, it will almost be a moral impossibility to ignore the demonstration.” See 

Some Principles of Maritime Strategy, J. S. Corbett, ed. E. J. Grove (London: 

Brassey’s, 1988), p. 303. Geoffrey Till, “Corbett and the 1990’s,” Mahan is Not 

EnoughThe Proceedings of a Conference on the Works of Sir Julian Corbett and 

Admiral Sir Herbert Richmond, ed. James Goldrick and John B. Hattendorf (Newport, 

RI: Naval War College Press, 1993), p. 224. 

143. The minimum weather conditions needed to support visual flight operations is 

likely to be roughly sufficient for the employment of the HEL and its sensors. 

144. The HEL also may have significant utility during replenishment operations. 

Unlike other defensive systems, it can be employed without undue hazard during refueling and ordnance handling evolutions. 

145. While Naval aviators have long aspired to achieve this goal, the limitations of 

both offensive and defensive systems previously made it impractical. Hughes summarizes the issues that confronted Nimitz during the Second World War and led to the 

adoption of the massed defense. See Hughes, Fleet Tactics, pp. 104-105. 
Directed Energy and Fleet Defense . . .73 

146. Boyd, p. 174. 

147. Designers seek to minimize heat dissipation requirements and power demands 

by operating at lower voltages; unfortunately, such an approach reduces the amount of 

energy needed to damage or disrupt the device. This is the inherent risk in adopting the 

commercial standard for military applications. The one positive development is the 

trend towards more fault tolerant architectures that incorporate automatic “soft resets” 

when disrupted. 

148. Sowders, pp. 19-20. 

149. There are limited data that suggest certain modulation patterns may increase 

the probability of disruption. Additional research is necessary before one can assess 

whether this can be exploited in the design of operational systems. See Sowders, et al. 

150. Merritt, op. cit. 

151. Sowders, p. 30. 

152. Senator Tom Harkin (D-IA) has led the fight against the MIRACL testing in 

Congress calling it “both unnecessary and provocative.” He is quoted by Inside the 

Army as saying, “The Congress, the White House and the Pentagon have to have a serious discussion of our nation’s anti-satellite weapons plans before we go down the road 

of testing these weaponsalthough the Pentagon is spinning the tests as a way to 

measure U.S. satellite vulnerability, most arms control analysts would describe the test 

as a major step in developing an ASAT weapon. These are the same types of tests that I 

and others in Congress objected to years ago.” Inside the Army, November 30, 1998, 

pp. 13-17. Quoted in AFSPC Legislative Liaison, December 10, 1998. Whether one 

agrees with the senator or not, his remarks make it evident that there are major unresolved national strategy issues regarding development of any anti-satellite capability. 

153. Los Angeles Times, 28 November 1998, quoted in AFSPC Legislative Liaison, 

December 10, 1998. 

154. Development of an embedded HPM feature as an adjunct capability in future 

high power radar systems may be a prudent investment; however, the fundamental susceptibility to countermeasures does not support independent development for ship selfdefense applications. 
74 . . . Directed Energy and Fleet Defense 

Center for Strategy and Technology 

The Center for Strategy and Technology was established at the Air War 

College in 1996. Its purpose is to engage in long-term strategic thinking 

about technology and its implications for U.S. national security. 

The Center focuses on education, research, and publications that support 

the integration of technology into national strategy and policy. Its charter is 

to support faculty and student research, publish research through books, articles, and occasional papers, fund a regular program of guest speakers, host 

conferences and symposia on these issues, and engage in collaborative research with U.S. and international academic institutions. As an outside 

funded activity, the Center enjoys the support of institutions in the strategic, 

scientific, and technological worlds. 

An essential part of this program is to establish relationships with organizations in the Air Force as well as other Department of Defense agencies, and identify potential topics for research projects. Research conducted 

under the auspices of the Center is published as Occasional Papers and disseminated to senior military and political officials, think tanks, educational 

institutions, and other interested parties. Through these publications, the 

Center hopes to promote the integration of technology and strategy in support of U.S. national security objectives. 

For further information on the Center on Strategy and Technology, 

please contact: 

Grant Hammond, Director

Theodore C. Hailes, Deputy Director

Air War College

325 Chennault Circle

Maxwell AFB

Montgomery, AL 36112

(334) 953-6996/2985 (DSN 493-6996/2985)

Email: grant.hammond@maxwell.af.mil

ted.hailes@maxwell.af.mil

William C. Martel, Occasional Papers Editor

Naval War College

(401) 841-6428 (DSN 948-6428)

Email: martelw@nwc.navy.mil
Directed Energy and Fleet Defense . . .75 

Titles in the Occasional Papers Series 

1 

Reachback Operations for Air Campaign Planning 

Scott M. Britten, September 1997 

2 

Lasers in Space: Technological Options for Enhancing US Military 

Capabilities 

Mark E. Rogers, November 1997 

3 

Non-Lethal Technologies: Implications for Military Strategy 

Joseph Siniscalchi, March 1998 

4 

Perils of Reasoning by Historical Analogy: Munich, Vietnam, and the 

American Use of Force Since 1945 

Jeffrey Record, March 1998 

5 

Lasers and Missile Defense: New Concepts for Space-Based and 

Ground-Based Laser Weapons 

William H. Possel, July 1988 

6 

Weaponization of Space: Understanding Strategic and Technological 

Inevitables 

Thomas D. Bell, January 1999 

7 

Legal Constraints on Information Warfare 

Mark Russell Shulman, March 1999 

8 

Serbia and Vietnam: A Preliminary Comparison of U.S. Decisions To Use 

Force 

Jeffrey Record, May 1999 
76 . . . Directed Energy and Fleet Defense 

9 

Airborne and Space-Based Lasers: An Analysis of Technological and 

Operational Compatibility 

Kenneth W. Barker, June 1999 
The Occasional Papers

series was established by the

Center for Strategy and Technology

as a forum for research

on topics that reflect

long-term strategic thinking

about technology and its

implications for

U. S. national security.

Center for Strategy and Technology 

Air War College 

Maxwell Air Force Base 

Montgomery, Al 36112