CIA-RDP96-00789R002000140003-2

CPYRGH KEEP W/2-3
14 SEP '87
ARMY 11H25
Work Continues on U.S. FaserSite in Desert
WHITE SANDS MISSILE
RANGE, N.M. - The nation's first
ground-based, free-electron la-
ser, perhaps the precursor to weap-
ons that could strike enemy mis-
siles as they rise from their launch
pads, is under construction.
The $1.7 billion Strategic De -.
fense Initiative project, managed by
the Army's Strategic Defense
Command, could develop the tech-
nology for a key element in a com-
plex of strategic defense systems
which could defend either the
United States or its allies.
About 20 miles east of White
Sands' main post, a wide drive an-
gles away from the main road
-deep into the desert scrub brush.
Culverts for drainage, a drilling
derrick for water wells, power lines
and building excavations line the
way to an expanding rectangle of
cleared land that marks the site
for an ambitious experiment in la-
ser technology.
According to treaties with the
Soviets, White Sands and the Pacif-
ic atoll of Kwajalien are the two
U.S. testing ranges designated for
strategic defense experiments.
After a series of environmental
studies, the 20 square-mile Oro
Grande location was selected.
"We have to bring in water,
power [about five times what all of
White Sands presently uses] and
roads- build a whole research
complex," said Col. James F.
MeNulty, head of the GBFEL tech-
nology integration experiment.
MeNulty is a tall, silver-haired
field artilleryman who served two
tours of duty in Vietnam, but who
also found time between field as-
signments to study at a half-dozen
prestigious institutions, including
Massachusetts Institute of Tech-
nology and Lawrence Livermore
National Laboratory, where he
gathered advanced degrees in nu-
Clear physics and management
before receiving his present assign-
ment in January 1986.
White Sands Missile Range Illustration
An artist's conception of the Ground Based Free Electron
Laser experiment now under construction at White Sands
Missile Range shows the facilities for forming the beam in
- His first months on the job
were spent attending the Defense
Systems Management College at
Fort Belvoir, Va., during the week
and traveling around the country
trying to organize the project on
weekends. His staff has grown
from zero to 42 in the first year and a
half, although, he said, laser and
optical experts are a rarity.
"It is exciting," he said. "I start-
ed with absolutely nothing but a
piece of paper. [Lt.] Gen. [John]
Wall [commander of the Washing-
ton-based SDC] said to me, 'Don't
come back until it works.'"
While the project is seen as an
experiment and not a weapon sys-
tem, it is aimed at a well-defined
military end. The Army has defense
applications for the technology if
it is approved for further develop-
government.
It is part of a futuristic trend
that will place the American soldier
farther from his enemies, but will
at the same time extend the strate-
gic battlefield, McNulty said.
.A ground-based laser, if used in
a weapon system, would work in
conjunction with a relay mirror
in stationary (geosychronous) orbit
over the laser site, and fighting
mirrors orbiting over areas such as
the Soviet Union that might be
expected to launch missiles. The la-
ser beam, generated on the
ground and reflected over tens of
thousands of kilometers by mir-
rors, would focus on and destroy tar-
gets such as the ballistic missile
and the "buses" that can carry 10 to
15 warheads plus dozens of
decoys.
the foreground. An underground tunnel takes the laser
beam to the opposite end of the facility (3 to 5 kilometers
away) for transmission into space.
intepretation of the ABM treaty,
work on the free-electron laser
can go ahead, because it is a fixed,
ground-based element and there-
fore "treaty compliant." Application
of the treaty to the mirrors being
developed by other Army and Air
Force teams is under study.
Interestingly enough, even
MeNulty doesn't know what the fi-
nal design of the laser will look
like. It could be either a long,
straight structure (the induction
laser proposed by TRW and Law-
rence Livermore National Lab-
oratory) or a more compact, race-
track design (the radio frequency
[RF] laser proposed by Boeing Aero-
space Co. and Los Alamos Na-
tional Laboratory). The final choice
is to be made by the end of fiscal
1988.
generation of a stream of electrons,
the charged particles that vibrate
around the nucleus of an atom. The
electrons are injected into a
charged medium, stripped from
their atoms (thus the name free- .
electron) and then accelerated to
near the speed of light.
The induction laser uses the
magnetic fields produced by large
magnets to speed up the elec-
trons; the RF laser employs radio
waves pumped into resonant cav-
ities to do the same thing.
The speeding electrons are
then passed through a device with
varying magnetic fields which are
used to make the electrons oscillate
or move back and forth, hence the
box is known as a "wiggler."
Each time the electron wiggles,
See LASER, Page 40
mentAnddroveatot Release 2000/08/b: CARDP96-00789R002000+40003-2
Ambrose in No Word for Dabyen Cat Vary Replacement

Approved For Release 2000/08/08 : CIA-RDP96-00789R00200014000342
Sandia National Laboratories Photo
CPYRGHT
An 8-inch howitzer used by scientists at
Sandia National Laboratories shoots a new
shell design through monitored targets.
Researchers there are using technology
developed in the nuclear weapons program
to create improved conventional weapons.
1
said Max Newsom, manager of the
advanced projects department. It
/fuse combination would provide
a wide range of options that, for ex-
ample, could reduce the mili-
tary's logistics tail and at the same
time improve the weapon's
effectiveness.
IUW SJU.
"Advanced conventional muni-
tions are of increasing national im-
portance and we have only
scratched the surface of their poten-
tial capability," Newsom said.
Sandia is not operating on an
unlimited budget, however, and the
See SANDIA, Page 42
Laser
From Page 35
photons, tiny particles of light, are
produced. Through subsequent
stimulation of the electrons by the
photons, up to 40 percent of the
electron beam's energy is extracted
to produce the high power laser
beam.
In the induction device, a small
"seed" laser, operating at a pre-de-
termined frequency, is fired into
a 100-foot-long wiggler. The seed la-
ser is amplified as energy is ex-
tracted from the electron beam and
converted to light energy at the
same frequency as the seed laser.
The electron beam, as it exits the
wiggler, is quickly separated and
discarded so that only the laser
beam goes on to the optical system.
The laser beam is focused to
about the diameter of a pencil, is
then allowed to expand (to about
one meter) naturally in a vacuum as
it moves through a 3- to 5-kilome-
ter-long beam tunnel. It must ex-
pand, otherwise, the focused
beam is powerful enough to blow
apart the mirror designed to di-
rect it into space.
& Army Tines SEPTEMBER 21, 1987
The RF concept does not use a
seed laser. The light produced by
the electron beam is reflected
back and forth in the wiggler be-
tween sets of mirrors (called a
ring resonator and the size of a foot-
ball field), each time generating
more photons and finally being al-
lowed to escape through a hole in
the mirror to the optical system.
In December, a request for pro-
posals will be sent out to industry
from the ground-based laser pro-
ject office. In February, industrial
competitors will submit their
plans and designs. And in June,
McNulty and his team will pick
the winner.
"Each team has technical mile-
stones to meet before the decision is
made," McNulty said.
He noted that even then the
team still won't know for sure if the
design works.
"But we will at least know what
the unknowns are," McNulty said.
One of those unknowns is how
to keep the electron and light beams
stable and straight in the long
wiggler of the induction laser.
"In the optical guidance
scheme, the electrons ride in a
trough, or tunnel, of light,"
MeNulty said. The packets of elec-
trons and light must be exactly in
synchronization. If we can't keep
them in the trough, we will never
have the efficiency we need. We
should have evidence by the end
of December if it can work."
The RF laser also has its prob-
lems. Using mirrors to multiply the.
light forces researchers to the
ragged edge of technology. The
needed lenses (mirrors) have to
be of two types: paraboloid and
hyper-paraboloid. The paraba-
loid has an off-center focus. The hy-
perparaboloid is specially de-
signed for reflections at glancing
grazing angles.
"Where we can't put light di-
rectly onto a mirror, we skip it off,"
McNulty said.
White Sands Missile Range Illustration
of mirrors based in space. Ultimately it will
Turrets will house the control system that
ApprovedsFonRelease 12009/08/08 -: CIA-RTP9600789R-002000h4000342ª
manufactured laser beam toward a system
destroy them.
Both types of mirrors are nec-
essary for the RF laser to work. Both
have been designed and are in
the final stages of fabrication, but
remain to be tested. The testing is
scheduled for December and
January.
After the laser beam is generat-
ed it has to be controlled in a vacu-
um and then shaped and correct-
ed for atmospheric effects before it
is reflected into space from a
ground mirror. Reseachers have the
formidable task of building a
four-meter-wide mirror to direct
the beam. There also is a "signifi-
cant engineering challenge" to use a
single aperture to receive the
beacon beam coming down and
transmit the weapon beam going
up, McNulty said.
There are some more knotty
problems with using lasers in the at-
mosphere over long distances.
"Laser beams don't like air,"
McNulty said.
Turbulence, water, dust or
eddy currents in the atmosphere
can affect a laser beam just as fog
can disperse a light beam.
Also, a laser beam heats the air
through which it travels. That
causes the air density to change,
which bends the laser beam and
produces "thermal blooming,"
which once again dissipates its
power.
Finally, nitrogen in the air ab-
sorbs the photons, or particles of
light, that make up a laser beam.
Nitrogen alters the wave lengths of
the light and spits it out in other
directions.
"Those are the three things we
have to overcome," he said.