Defense

Hughes Aircraft Corporation research laboratory.3 To develop the

laser, a material had to be found in which an assembly of atoms, most

of which were in a higher energy state than the ground state (or lowest energy state) of the atom, could be created. Such a condition is

called a population inversion. Where it exists, a light pulse can be

amplified by stimulating the emission of radiation by the atoms in

the higher energy state. Thus, a strong light pulse can be obtained

using a small stimulus—hence the term amplification. Maiman

found that a population inversion could be produced within certain

atoms in an appropriately designed ruby rod by irradiating it with a

strong pulse of light. The atoms in the higher energy states could be

stimulated to emit radiation by a very weak light signal of the proper

frequency, which would create a cascade that would stimulate the

emission of light by all other atoms in the higher energy state, producing a strong pulse of red light. 

About the same time, Ali Javan and his collaborators at Bell

Laboratories discovered a way to create a population inversion in a

mixture of helium, neon, and other gases.4 The tube in which these

gases were placed was irradiated continuously with light of the

appropriate wavelength. A population inversion was created in the

gas mixture, which created a tightly focused beam at a sharply

defined wavelength. This tight focus bore out Einstein’s 1916–1917

prediction. His calculations revealed that the light quanta or photons created by the stimulated emission are in exactly the same

quantum state as the photon that initiated the stimulated emission.

This means that all the photons in the process are moving in exactly

the same direction, thus creating the tightly focused beam.

Introduction and Scientific Background

Albert Einstein spent World War I in Berlin, where he developed a theory that described electromagnetic radiation in equilibrium with atoms that could emit and absorb radiation. The innovation in Einstein’s work, which was published in 1916 and 1917, was

that he used the newly developed quantum theory to obtain his

results. The most important result was not only that the atoms in the

assembly could absorb and emit radiation spontaneously but also

that atoms in certain excited states could be induced to emit radiation.1 Einstein called this discovery the stimulated emission of radiation. Einstein’s discovery provided the basis for the development of

lasers, though the phenomenon would not be observed in the laboratory for many years.

The development of radar during World War II required intensive research in microwave radiation. The need for highly sensitive

radar receivers led to isolating and observing for the first time Einstein’s stimulated emission of radiation. In 1954, Charles H. Townes,

J.P. Gordon, and H.J. Zeiger were the first to amplify a microwave signal by using stimulated emission.2 They called their device the

maser, which stood for Microwave Amplification by the Stimulated

Emission of Radiation. This work led many to speculate about applying the same principles to radiation in other regions of the electromagnetic spectrum. This effort turned out to be successful, and 6

years later, a positive result was achieved with visible light.

The first laser (Light Amplification by the Stimulated Emission

of Radiation) was developed by Theodore H. Maiman in 1960 at the

The Airborne Laser from Theory

to Reality: An Insider’s Account

by Hans Mark

Center for Technology and National Security Policy

The National Defense University (NDU) established the Center for Technology and National Security Policy in June 2001 to study the implications of technological

innovation for U.S. national security policy and military planning. The center combines scientific and technical assessments with analyses of current strategic and

defense policy issues. Its major initial areas of focus include: (1) technologies and concepts that encourage and/or enable the transformation of the Armed Forces, 

(2) developments by defense laboratories, (3) investments in research, development, and acquisition and improvements to their processes, (4) relationships among

the Department of Defense, the industrial sector, and academe, and (5) social science techniques that enhance the detection and prevention of conflict. The staff is

led by two senior analysts who hold the Roosevelt Chair of National Security Policy and the Edison Chair of Science and Technology and who can call on the expertise

of the NDU community and colleagues at institutions nationwide. The papers published in the Defense Horizons series present key research and analysis conducted

by the center and its associate members.

A publication of the

Center for Technology and National Security Policy

National Defense University

APRIL 2002

Number 12

Horizons

April 2002 Defense Horizons 1
Hans Mark is a professor in the Department of Aerospace Engineering and

Engineering Mechanics,The University of Texas at Austin. Dr. Mark can be

reached at hmark@mail.utexas.edu.

Solid-state and gas lasers of the type described here are limited

in terms of the energy that the laser beam contains because the population inversion is eventually destroyed by melting or other change

in the state of the medium in which it is created. The best continuous energy both in pulsed and continuous wave beams is of the order

of kilowatts. Lasers of this kind are useful for many purposes, including meteorology, bar-code scanning, and target designation. One of

the most fascinating applications of a solid-state laser with energy in

the kilowatt range is the lunar laser ranging experiment conducted

for the past 30 years at the University of Texas McDonald Observatory. During the Apollo missions, the astronauts placed corner reflectors on the Moon that would later be used to reflect very short and

intense laser pulses fired from Earth. The purpose of this experiment is to make precise measurements of the parameters of the

lunar orbit. The laser can determine to within a few centimeters the

position of the reflector with respect to Earth. Through these measurements, scientists have established that the Moon is receding from

Earth at the rate of a few centimeters a year. What is remarkable

about this experiment is that it illustrates how tightly focused a laser

beam can be made so that it can traverse about half a million miles

and still be intense enough for accurate measurements when the

pulse returns.5

The lasers mentioned so far cannot be used as weapons

because they lack the beam energy to cause material damage. Further innovation was required to produce laser beams with the requisite energy. Several research groups realized that producing a population inversion in a moving medium would create higher energy

laser beams, because the energy generated by the process to create

the population inversion (either by irradiation or combustion) could

be dissipated rapidly. In 1967, Edward T. Gerry and Arthur

Kantrowitz at the AVCO Everett Research Laboratory were the first

to produce a good quality laser beam with a continuous wave energy

in excess of 10 kilowatts. In March 1968, they succeeded in creating

a laser beam at a wavelength of 10.6 microns in a supersonic flow of

a nitrogen-carbon dioxide gas mixture with a continuous wave intensity of 138 kilowatts. This achievement made it possible to start

thinking about the use of high-energy laser beams as weapons that

would have military value.

Laser Weapons

As a result of a 1968 briefing about the high-energy laser program being carried out by the Defense Advanced Research Projects

Agency and the U.S. Air Force under the code word Eighth Card, a

subcommittee of the U.S. Air Force Scientific Advisory Board was

established to study how this technology could be developed to create militarily effective weapons. In 1969 and 1970, the subcommittee

(of which I was a member) met to consider possible applications of

laser weapons. At one meeting, Edward Teller was particularly

intrigued by the idea of what he called the aerial battleship—a large

airplane equipped with one or more high-intensity lasers. A futuristic aircraft of this type could escort bombers to defend them from

enemy attacks. The powerful airborne lasers would shoot down hostile interceptor airplanes as well as air-to-air and surface-to-air missiles, causing damage with energy traveling at the speed of light.

This last point was deemed the principal advantage of laser

weapons. Delivery of lethal energy with the speed of light would

greatly simplify the fire-control problem. No complex calculations

and guidance control solutions would be necessary to hit fast-moving

targets. Since the optical system has little inertia compared to conventional guns or rockets, rapid slew rates were possible. Finally,

lasers are capable of much more rapid firing rates than conventional

guns or rocket launchers.

Our subcommittee began to consider Teller’s idea seriously, and

we looked at some concepts for a prototype. What eventually emerged

from these discussions was a proposal to put a large carbon dioxide

gas dynamic laser on a four-engine jet aircraft. However, lively debate

developed among the subcommittee members over this proposal. One

faction believed that the carbon dioxide laser would be the wrong one

to use because of the known problems with atmospheric absorption

for the 10.6-micron wavelength beam produced by the laser. They

believed that it would be prudent to wait for the availability of a highpower laser producing a beam with a shorter wavelength and better

atmospheric penetration than carbon dioxide. The other faction, to

which I belonged, believed that it did not matter much what kind of

a gas dynamic laser was used because the carbon dioxide laser would

solve many system-level engineering and fire-control problems. Furthermore, it was not clear just when a large laser producing a shortwavelength beam would be available. Chemical lasers offered some

promising candidates, but none could operate at power levels as high

as a carbon dioxide laser. After some discussion, our subcommittee

recommended to the Scientific Advisory Board in April 1971 that we

initiate a program to put a large carbon dioxide laser on an airplane.

The Board approved the recommendation, and the airborne laser laboratory (ALL) program was born.

The Airborne Laser Laboratory

While the Air Force Scientific Advisory Board was discussing

the aerial battleship proposal, the Air Force itself took some action

to preempt the Board. On February 3, 1971, Air Force Headquarters

issued a directive calling for an accelerated demonstration program

to create an airborne laser laboratory. This directive, together with

the positive recommendation of the Board, provided the push necessary to get started. The proposal that eventually emerged was to

modify a Boeing KC–135 tanker aircraft to accept a large carbon

dioxide laser that would produce a beam with a continuous wave

energy of about 500 kilowatts. The airplane would also be equipped

with a fire-control system that would be sufficiently accurate to perform the proof-of-concept experiments that we had in mind.

Several large and complex technical problems had to be solved:

■ The airplane had to be modified to carry the large carbon dioxide

laser, and a method had to be established to mount the optical train in a flexible aircraft in such a way that the properties of the various laser beams in

the system were preserved.

■ An appropriate optical system had to be built to transport the highintensity laser beam to the turret in which the large mirror of the airborne

pointing and tracking (APT) system was mounted.

2 Defense Horizons April 2002
■ A window through which the high-intensity laser beam would pass

from the inside to the outside of the aircraft had to be developed.

■ The safe operation of the airplane with the APT turret in place had

to be established.

■ A flight-weight, high-intensity carbon dioxide laser had to be built

and tested and then mounted in the aircraft.

■ Perhaps most important, all of these components had to be integrated so that everything would work as a system.

The Air Force assembled an excellent team of people to manage

and execute this program.6 In addition, an extremely competent

group of contractors was assembled to carry out the development,

construction, and integration of the ALL system. The General Dynamics Company was engaged to modify the KC–135 aircraft and to build

the turret; the optical train and APT system were built and assembled

by the Hughes Aircraft Company. This job required the solution of

very difficult technical problems, and several setbacks were encountered. A primary mirror broke when it could not sustain the heat load

delivered by the high-intensity laser beam, and finding an appropriate material from which to manufacture the mirror was difficult. The

carbon dioxide laser was built by Pratt and Whitney and thoroughly

tested on the ground at an optical range near the Air Force Weapons

Laboratory at Kirtland Air Force Base. The entire system was integrated and eventually operated by an Air Force team at Kirtland.

In addition to the Air Force team and the contractors, other

Federal agencies made significant contributions to the program. The

National Aeronautics and Space Administration (NASA) was crucial,

and the NASA–Ames Research Center was in a good position to help.

Ames housed test facilities that could be used to solve the turret

problem and to establish the fact that the laser beam could be successfully propagated through the turbulent boundary layer that surrounds the aircraft. One of the large wind tunnels at Ames with a test

section 14 feet in diameter was activated and dedicated to the program.7 A great many turret configurations were considered, and it

was determined that a fairing would be required around the turret to

prevent turbulent flow that could lead to harmful vibrations. The

configuration that was finally selected performed successfully

throughout the test program. Another very encouraging result of the

tests at Ames was that it proved possible to send the carbon dioxide

laser beam through the turbulent boundary layer that surrounded

the aircraft without any significant distortion. The tests performed

in the 14-foot wind tunnel at Ames contributed significantly to the

ultimate success of the ALL program.

When the aircraft modifications were completed in January

1973, an extensive series of test flights were conducted at Edwards

Air Force Base that confirmed the wind tunnel tests performed at

Ames.8 Once the fundamental aerodynamic tests were completed,

tests that involved the laser system were initiated. These involved

both the ALL aircraft and target aircraft that would be used to measure the properties of the laser beams emitted by the ALL. At first, a

small T–39 aircraft was used, and later another KC–135 tanker aircraft was modified to serve as the target aircraft.

The laser tests were conducted in a series of cycles beginning

in May 1973 with a low-power carbon dioxide laser installed in the

ALL aircraft. The first fire-control tests were completed in November

1973. Each of the cycles involved more complex tests and at the end

of each cycle, progress was reviewed before the next cycle was initiated. At the completion of the second cycle, in June 1976, the Air

Force High Energy Laser Review Group performed a very thorough

review of the program and authorized proceeding with the remaining

cycles in the program. The methodology of using periodic milestones

to manage the program and then to review the results has proven to

be successful in complex programs such as this one.

The ALL program culminated in May 1983 with a test series

that resulted in the disabling of five Sidewinder AIM–9B missiles by

the airborne lasers at a range of 3 miles. In September 1983, the ALL

disabled two Navy drone vehicles (BQM–34A). These tests were

proof-of-concept experiments that demonstrated that airborne

lasers could bring down surface-to-air or air-to-air missiles. With the

successful completion of the ALL experiments, the aircraft was flown

to the Air Force Museum at Wright-Patterson Air Force Base in Ohio,

where it is on static display.9

The Airborne Laser Program

Two technical developments revived interest in the airborne

laser in the early 1990s. The first was the development of a chemical laser that could produce intense laser beams with a wavelength

of about 1.3 microns. Unlike the carbon dioxide laser, which has a

wavelength of 10.6 microns, the chemical laser beam is not strongly

absorbed by the atmosphere. This laser works using a chemical

reaction triggered by a hydrogen peroxide mixture between oxygen

and iodine. The chemical oxygen iodine laser (COIL) can deliver

beams of continuous-wave energy in the megawatt range. Also, at

the short operating wavelength, the COIL would have a range of

clear military interest.10

The second technical innovation since the ALL program was

concluded in 1983 was the development of adaptive optics. Adaptive

optics is a method for neutralizing the adverse effect that atmospheric turbulence has on the image of an astronomical telescope.

The idea is to build a mirror for the telescope that is made not of a

monolithic piece of glass but rather of segments that can be moved

quickly by piezoelectric actuators to compensate for atmospheric

turbulence. The atmospheric turbulence is measured by a pulsed

laser that uses the same optical train as the telescope itself. The

reflected laser signal from various segments of the path in the atmosphere is analyzed by a computer that drives the actuators to reshape

the mirror to compensate for the effect of atmospheric turbulence.

This method, first developed for astronomical telescopes, has been

adapted for the airborne laser.

These technical developments persuaded the Air Force leadership to initiate planning for an airborne laser in 1991. In 1994, the

Airborne Laser (ABL) Program was formally initiated, and in 1996,

Air Force Chief of Staff General Ronald R. Fogleman announced the

selection of contractors to develop the ABL weapon. The program

plan called for the modification of a commercial Boeing 747–400F

cargo aircraft to carry an advanced COIL. The continuous wave

energy of the laser would be in the megawatt range delivered at a

wavelength of 1.3 microns. 

The TRW Company built and tested a flight-weight COIL in

1997. In addition, positive developments were made in the technology

of mirrors and windows for the high-energy laser beam. However, the

April 2002 Defense Horizons 3
The Airborne Laser (ABL) Program

T

he first ABL aircraft recently completed 21 months of major structural modifications at the Boeing facility in Wichita, Kansas. In 2002, the

aircraft will make its first flight and will begin an incremental testing phase. Each individual segment of the weapon system will be tested

first on the ground and then in the air. The aircraft’s sophisticated battle management system will be the first to be tested. The battle management suite will enable the 747–400 freighter aircraft to detect and track boosting missiles from hundreds of kilometers away. The ABL will

hand-off missile tracks to other missile defense systems or to the aircraft’s beam control/fire-control system in preparation for engagement with

the high-energy laser. While these airborne tests are taking place, the beam control/fire-control system and the high-energy laser will be completely checked out on the ground. The entire beam control/fire-control train is being constructed on the ground at Lockheed Martin’s facility in

Sunnyvale, California. At the same time, a system integration laboratory is under construction at Edwards Air Force Base, where six laser modules

will be linked and tested. These systems will be integrated onto the aircraft and full system flight-testing will occur against a series of target

boards on aircraft and dropped from balloons. The ABL test program will culminate in the shootdown of a boosting ballistic missile in late 2004.

Upon completion of the test program, the ABL will be available for emergency use as part of the U.S. ballistic missile defense system. Additional ABLs will be built with incremental improvements as the technology matures, exploiting developments in adaptive optics, light-weighting,

chemical efficiency, solid-state lasers, and other sensors. ABL will provide a unique capability to intercept missiles during boost phase to complement the emerging U.S. capability to intercept missiles in mid-course and the existing capability in the terminal phase. As such, ABL is a critical element to a layered missile defense capability to protect forward-deployed troops and civilians.

Current program plans are to provide seven ABL aircraft that will be organized into a single squadron based in the United States. In a contingency or war, five ABL aircraft will be deployed at a single forward operating location. Once deployed, these aircraft will be capable of maintaining

two simultaneous, near-continuous combat air patrols and defend against boosting ballistic missiles. ABL also will provide theater-wide surveillance

against ballistic missiles and provide impact and launch point data to support active and passive defense, as well as attack operations.

The ABL role in missile defense is only the beginning for applications of this speed-of-light weapon. The Air Force is already exploring future

missions for ABL and high-energy lasers. Two potential applications are protection against high-flying cruise missiles and air-to-air missiles. In

addition, the Air Force Research Laboratory is exploring partnering the airborne laser with satellite mounted mirrors. Using these mirrors to relay

ABL’s powerful laser beam has the potential to dramatically improve ABL range.

The 30-year-old vision of Edward Teller is on the threshold of becoming a reality. A concept born in the Air Force research laboratories in

the early 1970s and nurtured through two to three generations of technology evolution, is close to reality today. The Airborne Laser aircraft and

its technology have been demonstrated. The remaining challenge is to integrate all the pieces into an effective weapon. Once this challenge is

met, ABL will usher in a new era of weaponry for U.S. defense.

—Colonel Ellen Pawlikowski, ABL Program Director

airborne laser, like any complex development program, also experienced problems and delays. Most of these involved cost increases and

the fact that developing some of the hardware components took

longer than originally estimated. Perhaps the most persistent technical question was the calculation of the range of the airborne COIL at

which it would have military value. The exact numbers are classified,

but the issue was clear: At what range could the ABL aircraft flying at

40,000 feet destroy an ascending ballistic missile? 

To support the complex range calculations, the Air Force has

performed a variety of experiments on atmospheric turbulence.

These included measurements performed using aircraft and highaltitude balloons, as well as experiments on the ground. Measurements were taken at many locations around the world to determine

whether geographic effects could influence the effectiveness of the

ABL aircraft. When these experiments were completed, the decision

was made to conduct a critical examination of what was known

about atmospheric turbulence in order to validate the range calculations that have been made. In November 2000, a report was issued

in which some range curves were presented based on the data available from experiments at the time.

Figure 1 shows the results in terms of the ratios of the range

divided by the classified range requirement in the operational

requirement document (ORD) for the ABL and the ratio of the beam

intensity to the kill intensity required for the classified designated

target missile in the ORD. The horizontal lines across the graph indicate the exposure time necessary to achieve the kill. The four curves

show what happens with no atmosphere (which follows the inverse

square law), for an atmosphere with average turbulence, and for

atmospheres having half and twice the average turbulence levels as

determined by the experiments. What this picture shows is that at

the ORD range, the ABL aircraft could kill the missile defined in the

ORD with an exposure of a little more than 1 second under average

conditions of atmospheric turbulence. The actual numbers are still

classified, though they clearly are of military interest. These results

would not have been possible without the existence of adaptive

optics and the COIL.

Another important series of experiments has just been concluded at the White Sands Missile Range. An optical range there has

a 30-mile path length and a low-power, solid-state laser situated on

a mountain (North Oscura Peak) that can be aimed at aircraft with

appropriate measuring devices flying within the range. The laser has

a simplified adaptive optical system similar to the one that will be

installed in the ABL aircraft. Two important experiments were performed in the past 3 years at this facility. One was to demonstrate

that the fire-control system intended for the ABL can find and track

4 Defense Horizons April 2002
an uncooperative target aircraft. The second was to

measure the effect of various levels of atmospheric

turbulence on the laser beam to see how adaptive

optics improves the situation (figure 2). The measurements have a large standard deviation for two reasons: the turbulence level at the altitude of North

Oscura Peak (7,000 feet) is much higher than it is at

the altitude where the ABL aircraft will operate, and

some systematic errors in the experimental equipment contributed to the statistical errors. 

Other significant progress has been made in the

area of component development. The most important

is the development of a very high-capacity pump to

supply the oxidizer (hydrogen peroxide) for the combustion chamber of the COIL. This was a difficult

problem to solve because the effervescent properties

of hydrogen peroxide make pump cavitations more

likely. Although so far this is an example of a success

story, the major problems in complex programs such

as this one almost always arise in the integration

phase of the program, when successfully tested components are assembled as a system. Thus, more problems probably will arise before the first missile shootdown is demonstrated in 2 or 3 years.

Operational Concepts

The initial idea was for an aircraft armed with an

airborne laser to act as an escort for other warplanes.

The capability to disable air-to-air missiles demonstrated in the 1983 tests constituted a proof-of-concept

test for missions of this kind. These experiments were

carried out in the same spirit as the bombing tests

against warships conducted by General Billy Mitchell

in 1921. What was accomplished was to prove that a

large laser could be mounted on an airplane and that

the fire-control problem could be solved. A laser-armed

aircraft could be built that could shoot down hostile

air-to-air or surface-to-air missiles threatening a group

of aircraft. The laser weapon could also be used to

shoot down hostile aircraft threatening to attack the

formation escorted by the ABL aircraft. Both air-to-air

missiles and interceptor aircraft are fairly soft targets

for the airborne laser weapon, so kills could be performed at relatively long ranges. The scenarios

described so far are essentially offensive ones that call

for the protection of aircraft flying into hostile territory. Defensive applications also might be considered.

Airborne laser aircraft could be deployed to prevent

the overflight of hostile aircraft. Patrols by ABL aircraft

over friendly territory would provide an effective

defense. Thus, Edward Teller’s vision of an aerial battleship would be realized.

Another mission that has been proposed for an

airborne laser is to shoot down ballistic missiles in the

boost phase. In 1981, I proposed that a fleet of ABL

Figure 1. Target Irradiance vs. Range 

(3 degree elevation angle) 

0.00

Intensity / ORD Range for Missile Class

Range / ORD Range for Missile Class I

0.50 1.00 1.50 2.00 2.50 3.00

0.000

5.000

4.500

4.000

3.500

3.000

2.500

2.000

1.500

1.000

0.500

No atmosphere (1/R ) 2

Average atmosphere

2x 0.5x

2.5 seconds

5 seconds

1 second

Range curves for the COIL mounted on the ABL. The solid curve shows the range with no

atmosphere, an inverse square of the distance. The other three curves indicate the ranges

for various levels of atmospheric turbulence. For reasons of classification, the numbers

cannot be included. Thus, ratios with respect to the operational requirement document

(ORD) are used.

Figure 2. Oscura Peak Experimental Results 

Rytov Factor

Strehl Factor

Adaptive Optics and Tracking Loop Closed

Adaptive Optics and Tracking Loop Open

0.01 0.1 1.0

0.01

0.1

1.0

Effect of adaptive optics on the laser beam derived from a large number of measurements

performed at the Oscura Peak facility at White Sands Missile Range. The Strehl factor is

a measure of the laser beam width at the target; the Rytov factor is a measure of atmospheric turbulence.

April 2002 Defense Horizons 5
down of a ballistic missile is scheduled for late 2004. This objective

almost certainly can be achieved. The United States is very good at

this kind of thing, having done it many times before with radar,

nuclear weapons, stealth aircraft, and smart weapons. The most

important fact is that the airborne laser is a truly new weapon—the

first directed energy weapon to fulfill an important strategic mission.

For this reason alone, it is important that the ABL program be completed. Once a new weapon is fielded, it always leads to important

applications not even considered during the development program.

These applications often turn out to be the decisive ones. There is

good reason to believe that the same will be true for the airborne

laser weapon.

Notes1 Albert Einstein, Verhandlungen der Deutschen Physikalischen Gesellschaft,

vol. 18 (1916), 318, and Physikalische Zeitschrift, vol. 18 (1917), 121. 2 J.P. Gordon, H.J. Zeiger, and Charles H. Townes, Physical Review 95 (1954):

282, and 99 (1955): 1264 . 3 Theodore H. Maiman, “Stimulated Optical Emission in Ruby,” Nature (August

6, 1960): 493–494. 4 Ali Javan, W.R. Bennett, and D.R. Herriott. “Population Inversion and Continuous Optical Maser Oscillation in a Gas Discharge Containing a He-Ne Mixture,” Physical Review Letters (February 1, 1961): 106–111. 5 A Neodymium-Yag solid state laser was used to produce the intense pulses.

6 Colonel Donald Lamberson, USAF, was the overall program leader and Colonel

Demos Kyrazis, USAF, served as the project manager during most of the duration and

was in charge of making the airplane work. Both of these officers had first class technical ability as well as outstanding managerial and leadership capacities. In addition,

there was a galaxy of brilliant younger Air Force officers, enlisted people, and civilians

who worked on the Airborne Laser Laboratory with great intelligence and dedication.

The intellectual sparkplug was Dr. Petros Avizonis, who began his career as an Air

Force officer and later became Chief Scientist of the Air Force Weapons Laboratory

for an extended period. 7 An experienced Ames researcher, Mr. Don. A. Buell, was put in charge of the

aerodynamic experiments to be performed using the facility. Colonel Kyrazis spent

much time at Ames working on the turret and boundary layer problems. He was joined

soon by First Lieutenant L. John Otten, USAF, who became a key member of the ALL

team. Eventually, as a Colonel, he headed the Air Force Laser program. 8 The tests were performed by by Don Buell, Demos Kyrazis, and John Otten.

9 All of the events that I have described in this section are the subject of Dr.

Robert W. Duffner’s excellent book Airborne Laser: Bullet of Light (New York: Plenum

Trade, 1997), which is a comprehensive history of the ALL program. 10 Alan I. Lampson, Richard C. Buggeln, Peter G. Crowell, James A. Rothenflue,

and Gordon D. Hager, U.S. Air Force Weapons Laboratory, 1977, accessed at

<http://de.afrl.af.mil>. 11 In May 1981, shortly after I left my position as Secretary of the Air Force, I

delivered the annual Charles H. Davis Lecture, “Technology and the Strategic Balance,” at the U.S. Naval War College. The lecture was reprinted in full in Technology

and Society 4 (1982), 15–32.

aircraft patrol ocean areas where Soviet submarines were known to

be located.11 Sensors would pick up a submarine-launched missile as

it broke water, and the high-intensity laser would shoot it down.

Because of the rapid slew rates possible with the laser weapon, the

aircraft would be capable of shooting down several missiles launched

in succession. (This capability has recently been demonstrated by the

tactical high-energy laser at the White Sands Missile Range. In September 2000, this laser shot down a salvo of two Katyusha rockets

launched within a second of each other.)

The scenario I described was appropriate during the Cold War

when the Soviet Union was the principal adversary. Given our ability

to locate Soviet submarines, a long-range laser would be required to

do what I suggested, and the carbon dioxide laser on the aircraft did

not have the range capability to execute the mission. It would be

some years before the technology necessary to extend the range of

high-intensity lasers was ready for application.

Iraqi use of short-range ballistic missiles during the Gulf War in

1991 renewed interest in solving the problem of shooting down ballistic missiles. For the first time since 1944, when the Germans used

V–2 rockets to bombard London, ballistic missiles were used in combat. The Iraqis used a modified Soviet Scud missile to bombard targets in Israel and in Saudi Arabia. The United States deployed

Patriot missiles to shoot down the Scuds in Israel and Saudi Arabia

but achieved only limited success. However, the fact that ballistic

missiles were used triggered a strong and successful effort to

upgrade the Patriot with the Advanced Capability Program to create

the PAC–3 missile. This weapon, which has been tested successfully

a number of times, is now being fielded by the U.S. Army.

Although the range of the airborne laser is classified, some general statements about applications can be made. Airborne lasers

would clearly be useful in any conflict near the Korean Peninsula,

essentially because overflight of hostile territory is less necessary in

this region than it is elsewhere for effective use of this weapon. Airborne lasers also would be effective weapons in some parts of the

Middle East and Europe. One could construct operational orbits for

ABL aircraft above the Mediterranean, the Arabian Sea, and the

Black Sea that would be effective in various possible engagements.

The operational concepts for the ABL aircraft would be to

deploy them in areas where potentially hostile actions by aircraft and

missiles (including ballistic missiles) are likely. Such deployment

could be a deterrent as well as a militarily effective weapon. A good

model for the deployment of ABL aircraft is the airborne warning and

control system (AWACS) aircraft as used in various situations

around the world since the aircraft were introduced 20 years ago.

AWACS aircraft are designed to control air combat operations. Thus,

the mere deployment of AWACS aircraft signals serious interest in a

region. Because laser-armed aircraft are valuable assets, they would

have to be escorted, just as the AWACS aircraft are protected by

fighter aircraft when they are deployed. The employment of AWACS

during the past 20 years is a model of what can be expected from the

airborne laser. When AWACS aircraft were first developed, the program called for the deployment of seven aircraft. At present, about

30 AWACS aircraft are in service around the world. A similar increase

in demand is likely in the case of the ABL aircraft.

Although many problems remain to be solved, the ABL program

probably will be brought to a successful conclusion. The first shoot6 Defense Horizons April 2002

Defense Horizons is published by the Center for Technology and National Security Policy through the

Publication Directorate of the Institute for National Strategic Studies, National Defense University.

Defense Horizons and other National Defense University publications are available online at

http://www.ndu.edu/inss/press/nduphp.html.

The opinions, conclusions, and recommendations expressed or implied within are those of the

contributors and do not necessarily reflect the views of the Department of Defense or any other

department or agency of the Federal Government.

Center for Technology and National Security Policy

Hans Binnendijk

Director