Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 87
6
Engagement
In this chapter the committee examines technology for reducing the logistics
burdens associated with combat engagements, including projectile weapon systems (gun
tubes and missiles) with an emphasis on precision guided munitions, energetic s
(propellants, explosives, and warheads), and directed energy systems. Technologies and
systems are assessed in terms of their potential for reducing logistics burdens for an
AAN battle force.
The principal logistics burdens directly linked with engagement are the weight
and volume of ammunition, the weight and volume of the lethal systems transported to,
from, and within the area of operations (operational and tactical mobility), and the
energy requirements for lethal systems that must be supplied from battlefield fuel. in
general, technology could reduce logistics burdens by ensuring that every round of
ammunition fired hits its target and is effective ("one round, one hit, one kill") or by
decreasing the weight requirement per round. Significant reductions in both of these
categories could be achieved through near-perfect situational awareness (SA), precision
guidance systems, and highly lethal munitions (or other kill mechanisms). Of these, SA
is critical not just to reducing the logistics burdens but also to engaging the enemy
successfully.
SITUATIONAL AWARENESS
The DoD defines SA (situational awareness) as "knowledge of one's location,
the location of friendly and hostile forces, and external factors such as terrain and
weather that may affect one's capability to perform a mission" (GAO, 19981. The
importance of SA to success on the battlefields of the next century cannot be overstated.
Accurate information about the locations of forces, capabilities, and intentions of both
friends and enemies, as well as details about the terrain and weather, have been
uppermost in the minds of commanders throughout history. Even before the time of
semaphores, scouts and couriers were essential to battlefield sensing and
communications. Army XXT forces will have networked computers capable of passing
digitized information, including detailed images and processed intelligence, to all levels
of the command hierarchy. In the AAN time frame, continuing advances in information
technologies should ensure even better SA. Appendix F discusses the range of
opportunities for and the potential pitfalls of the information processing and
telecommunications technologies with the greatest potential impact on AAN logistics.
SA begins with knowledge of friendly and enemy locations, but SA technologies
involve more than the global positioning system (GPS). Accurate SA will provide the
87
OCR for page 88
88
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
operational information required to project a battle force of appropriate size, with the
right suite of weapons and equipment, at the optimum time and place. Determining the
numbers of soldiers, units, vehicles, and systems for a "right-size" force is essential for
Togisticians to provide "just enough" materiel (i.e., with allowances for risks) and to
avoid burdening the force with excessive quantities of ammunition "just in case."
SA has always been an important factor to support weapons systems for both
standoff platfor~ns and close engagement. In Army XXI, and even more so in AAN, the
reliance on maneuver and precision fire to achieve technological overmatch will make
near-perfect SA a prerequisite for successful engagement. Figure 6-1 is a schematic
representation of the system components needed for near-perfect SA. Computation
functions at the sensors, at the command and control nodes, and at the response
platforms will require detection, identification, and multisource fusion algorithms even
more robust than they are today for mission-critical functions. Otherwise, an opponent
skilled in camouflage and deception could defeat the SA system and escape detection.
The Army's critical dependence on SA technologies increases the likelihood that
information warfare techniques, including electronics countermeasures, will be used.
The communications links must be exceptionally robust. Large amounts of data will
have to be transmitted securely, with guaranteed reception, over a complex and rapidly
changing network, in the face of sophisticated attempts at disruption and spoofing.
At present, precision guided, or "smart," munitions are relatively expensive and
are reserved primarily for high-value targets. Highly reliable, miniaturized, integrated
systems for sensing and guidance control that can be produced inexpensively and in
large quantities will be essential for an AAN battle force that relies on precision
munitions for all of its indirect-fire close support.
Networks of miniature, inexpensive sensors will provide the wide-area coverage
and advanced warning inherent in the concept of near-perfect SA. Examples include
sensor networks for detecting and identifying chemical and biological warfare agents
and acoustic sensors for detecting vehicle movement, human movement, and voices.
For the terrain guidance discussed in Chapter 5, the SA system will require a
combination of (1) previously stored (in each vehicle) "unchanging" data, such as a
terrain database, (2) "look ahead" sensor and processor systems on vehicles that can
update information on transient and alterable features (e.g., visibility, soil conditions,
road and bridge damage, and mine detection), and (3) remote sensing images and wide-
area alerts (e.g., moving target indication) from satellites or UAVs. Real-time integration
of data from all of these sources into a "here-and-now" presentation will have to be
available on every vehicle to realize the AAN vision of open-formation, high-speed,
collaboratively self-routing charges of combat vehicles through the killing zone. For
shooters on these vehicles to achieve one round, one hit, one kill accuracy against targets
that are beyond their line of sight, the in-vehicle presentation system must be linked with
targeting and fire control systems.
The SA system for logistics command and control will also depend on sensors,
data processing, information integration, and decision-support aids. Technologies
applicable to SA in the AAN battle space will have the capability to reduce logistics
inefficiencies by minimizing the number of "just-in-case" support requirements. But the
full range of opportunities will be realized only if the Army continues to exploit rapid
advances in the underlying technologies, rather than assuming that SA has been
optimized by a revolution in military logistics when Joint Vision 2010 has been realized
(DoD, 1996~.
OCR for page 89
ENGA GEMENT
Remote Sensor Suite
D al
n
Command Center
Data Fusion
Target Prioritization
Communications
USES Link
~ ('
_ Local
Processing and
Data Compression
FIGURE 6-1 Schematic representation of the situational awareness system.
89
Remote Sensor Suite
Parallel
Interconnect
Complex Sensor
Array
Weapon System
Target Acquisition
Guidance
Smart Munition
1 ~)~9
During the study, committee members became concerned that AAN planners
and proponents were sometimes complacent about keeping abreast of rapid changes in
SA technologies. Even if Army ~ (the Army of the 2010 time frame) has "mental
agility" compared with opponents of that era, this technological superiority could erode
rapidly as the technologies continue to advance. Even if the Army has an unprecedented
level of SA by 2010, it must be prepared to maintain its advantage to 2025 (and beyond).
Appendix F highlights some of the technical reasons the committee believes that
maintaining superiority in SA will be a demanding task. First, simply maintaining and
upgrading the interconnecting hardware and software systems will be a daunting
challenge for the Army, as it is for commercial organizations that have only a fraction of
the Army's workforce and installed technology base. Second, much of the enabling
information processing technology (i.e., "computers") will continue to be driven by
commercial markets, rather than by military specifications or DoD requirements.
However. the Armv cannot assume that commercial markets will solve all of its difficult
,
~ ~ ~ ~ - ~ ~ . ~ ~ . ~ ~ ~ ~ ~ ~ . .
problems te.g., t1eld1ng components that are reliable and rugged under conditions
anywhere in the world).
Third, the rate of advance of any specific SA technology over several decades
will be unpredictable. Therefore, the Army can neither rely on a continuation of trends,
even if they are well established, nor assume that a physical limit will inevitably halt
OCR for page 90
9o
RED UCING THE LOGISTICS B URDEN FOR THE ARMY AFTER NEXT
advances in SA capabilities for which that technology seems to be essential. An example
(described in Appendix F) is the current debate in the semiconductor and microprocessor
technical community about the applicability of Moore's Lawt to 2010 and beyond. The
bottom line is that the Army cannot assume that trends in advancing the fundamental
technologies for SA will remain constant until the AAN era. If and when technology
trajectories change, the Army must be prepared to adjust its planning assumptions for
maintaining SA dominance and must then follow through with the efficient execution of
a timely strategy. If a trajectory shift occurs, an opponent with less advanced
technologies may no longer have to modernize a large installed base. This change could
give an otherwise overmatched opponent a technological agility that could unde~ine
the near-perfect SA on which an AAN battle force will depend.
Rapid innovations in all SA-relevant technologies-including those for basic
computing and information processing capabilities will continue well beyond the time
frame for incorporating today's technology into Army XXI. Opponents with later, and
therefore better, technology must not outpace AAN forces. SA capabilities must be
continually upgraded beyond Army XX], within resource constraints, without
compromising system integrity. The committee believes continuing modernization will
be a daunting challenge, especially because new SA systems will be required to meet as
yet unidentified AAN engagement system requirements.
PROJECTILE WEAPON SYSTEMS
Technologies for projectile weapon systems can reduce logistics burdens by
helping to achieve "one round, one hit, one kill" and by decreasing the total weight
transported per round fired. Total weight transported includes the weight of the lethal
system and supporting elements (including troops), as well as the weight of the round.
This section examines prospective technologies for gun systems, small missile systems
for precision attack, precision guided munitions, and energetics, primarily in teas of
their potential for reducing logistics burdens of ammunition and fuel. In several
instances, the committee uses current system concepts to illustrate the significant factors
that can increase or decrease logistics demands and that will be needed in AAN battle
force engagement systems.
Gun Systems
Alternative gun propulsion technologies with significant implications for
logistics burdens include the electrothermal chemical (ETC) gun, the electromagnetic
(EM) gun, and liquid propellants for conventional gun systems. All three have
advantages and disadvantages in terms of reducing logistics burdens.
Moore's Law is an empirical generalization first stated in 1965 by Gordon Moore, then the
chairman of Intel Corporation. Moore observed that a graph of the growth of memory chip capacity
(measured in numbers of transistors per chip or millions of instructions executed ner second) approximated
an exponential growth curve with a doubling time of one year.
--a ~rr
OCR for page 91
ENGA CEMENT
Electrothermal Chemical Gun
91
One way to increase the range of solid propellant, cartridge-based rounds is to
add energy to the propellant combustion via an electrically generated plasma. This is the
basis for the ETC gun currently under development by the Army. By implementing the
ETC concept, muzzle velocity can be increased using the same amount of gun propellant
as in current rounds. This should enable the design of smaller guns and ammunition in
the future. The drawback to the ETC gun is the high power required to generate the
plasma.
The potential logistics implications of the ETC gun are that the same perform-
ance as current rounds could be achieved with smaller, lighter rounds, or rounds of the
same weight would need less solid-propelIant energy and would thus be less sensitive to
hazards. Alternatively, rounds of current weight could have more than a 10 percent in-
crease in muzzle velocity, a greater range, and a higher probability of kill by incorporat-
ing projectile guidance sensors and controls. Among the disadvantages to be considered
are the added weight of the external power source and the fuel needed to re-energize it.
Army demonstrations of the ETC gun concept have proved that it can augment
the chemical energy from gun propellants. The Army objective for this concept is 18 MJ
muzzle energy (i.e., combined chemical and plasma energy) and I.9 km/s muzzle
velocity. The basic design of the plasma generator has been completed and could be
added to new shells with minimal changes in production processes.
A principal barrier to implementation is that energy storage devices, which must
be compact but have the high power density required to develop the 0.5 to 5 M} plasma
energy, have not been developed. Other major hurdles are the sensitivity of the plasma
generator to rough handling and the lack of solid-state switches that can handle high
power densities.
Electromagnetic Gun (Rai! Gun)
A propulsion technology with the potential for greatly increasing the muzzle
velocity of projectiles is the EM (electromagnetic) gun, also known as the rail gun. The
projectile is accelerated by the strong magnetic field generated when a large electrical
current passes through the projectile as it crosses between two conducting rails running
the length of the gun tube. Because EM gun technology has the muzzle velocities needed
to fire kinetic energy projectiles capable of penetrating the best passive armor (velocities
of 2.4 km/s and higher), it is often promoted as the antiarmor armament for a combat
vehicle capable of direct-fire "duels" in tank-on-tank engagements. The high muzzle
velocity attainable even for large rounds also makes it suitable as a long-range, indirect-
fire weapon, particularly if the round carries a guidance system for homing in on the
target.
A 1987 study by the Army Science Board found that that EM technology might
save on weight and volume because fuel to make electricity would replace the propellant
charge (not the warhead). Fuel consumption would increase somewhat, but the decrease
in ammunition logistics would be significant (ASB, 1987~. The STAR 21 Lethal Systems
report included the following information about high velocity, kinetic energy penetrator
(KEP) technology:
OCR for page 92
92
REDUCING THE LOGISTICS BURDEN FOR THE ARMY AFTER NEXT
Two factors are fundamental to defeating armored vehicles: (1) penetration
and (2) target damage. Penetration of advanced armors, such as ceramics, can be
enhanced by increasing the penetrator velocity to above 1.7 km/s. This velocity is
close to the upper limit of high performance conventional guns. There are also
practical limits to the mass that can be propelled by conventional guns. But the EM
launch technology offers the prospect of a substantial increase in both factors.
Although armor design can continue to be improved, the possibilities are limited
inherently on the defensive side by the weight of armor that can be tolerated in a
vehicle. Further, it is very difficult to divert or intercept a KE projectile.
(NRC, 1993c, p. 2)
The STAR 21 main report included the following statement on the potential of
the EM gun for Tong-range heavy artillery:
One potential [long-range heavy artillery] systems concept would combine
hypervelocity propulsion, to achieve range, with on board terminal guidance for
accuracy. Although hypervelocity projectiles are often discussed for direct-f~re
antiarmor applications..., the first fielded systems to use high-velocity electric
propulsion (whether electrothermal or electromagnetic) could well be long-range
artillery.... If the range of existing artillery could be effectively doubled, with
accuracy maintained or even increased through terminal guidance, the firepower
resulting from this technology would be of immense military significance.
(NRC, 1992,p.85)
The Army-sponsored Institute for Advanced Technology (IAT) and the Center
for Electromechanics at the University of Texas at Austin have been working on EM gun
technology since 1979 in coordination with the ARL, the Army Armaments Research,
Development, and Engineering Center, DARPA, and the U.S. Marine Corps (University
of Texas, 1998~. Muzzle kinetic energies of 9 M] and muzzle velocities up to 6 km/s
have been routinely achieved in the laboratory. lAT has now installed the first fully self-
contained rail gun at Yuma Proving Ground, Arizona, for field tests. The Materials
Research Laboratory, Ascot Vale, Australia, is also working on an EM gun.
EM gun technology is not subject to the same limitations on increasing the ki-
netic energy of a projectile that apply to conventional chemical propellants. Constraints
on projectile velocity begin to appear only at much higher muzzle velocities. Cowan
(1992) reports a 6 km/s velocity limit for high-performance EM guns because of a limit
on increasing momentum as the current increases. Aerothermal heating of an EM pro
_ _ ,
. , ., . ,, , ,, . , ., , , , , . ,, . , in, . .. . . . . ...
Jechle requires that the projectile have heat shielding above ~ kilos. At higher velocities,
an increasing amount of the muzzle velocity is quickly lost to aerodynamic resistance
(NRC, 1993c). The strength of the projectile materials may also become a limiting fac-
tor. However, KEPs with velocities of around 4 km/s can defeat all known armors.
One logistical advantage of the EM gun is the smaller weight and volume of the
round compared to a chemically propelled round with the same projectile mass (see
Figure 6-2~. A second advantage is that the round is less sensitive to inadvertent
reactions because it contains no energetic materials for propulsion. Third, because of
their higher projectile velocity, rounds fired from EM guns have a significantly higher
probability of kill, given a hit, than chemically propelled rounds.
A tactical limitation of EM guns as vehicle armaments is that they are line-of-
sight weapons until the aim point can be corrected while the projectile is in flight. This
OCR for page 93
ENGA CEMENT
FIGURE6-2 Railgun projectile.
93
limitation means that a vehicle-mounted EM gun for antiarmor assault is basically a
frontal or side-attack weapon although the most vulnerable part of most armored
vehicles is the top.
The major logistical disadvantage of EM gun systems is that they require a sub-
stantial source of battlefield electric power. They also require fast, solid-state switches
that can rapidly switch very high current Toads, which must still be developed. The
committee was briefed on a concept for a vehicle-mounted 105-mm EM gun. The gun
system, comprising the gun and autoloader, 42 rounds of ammunition, and the power
management system for the gun, was projected to weigh 10.3 tons. The power manage-
ment system included a 202-MJ pulsed power source (a compensated pulsed alternator,
called a "compuisator"), a lOO-M] lithium-ion battery for intermediate storage, thermal
management and high-power subsystems, and 50 gallons of fuel for the compuisator
(Johnson, 1997; Halle, 1997~. An Army integrated idea team also envisioned a 120mm
EM grenade launcher (Freeman, 1997~. The spoiler in these concepts is that weight,
packaging, and high power requirements severely limit the feasibility of EM armaments.
From the standpoint of logistics burdens, the EM gun system is too heavy to
serve as an antiarmor armament for an AAN armored combat vehicle. A concept briefed
to a member of the committee was a 40-ton vehicle with a 120-mm gun capable of
muzzle velocities greater than 2.1 km/s. A more likely application of EM gun technology
to the AAN battlefield would be as a long-range artillery weapon, which could support
battle force operations from as far away as 500 km, perhaps from the staging area. Fuel
supply logistics would be substantially simplified, and the principal technological
obstacle would be a terminal guidance system to ensure long-range accuracy.
A "corps artillery" system concept briefed to the committee would use
essentially the same 120-mm EM gun as the combat vehicle concept, but with the
compulsator on a separate vehicle platform. While this concept could be used for long-
range support, 20 tons per vehicle is probably still too heavy to meet AAN battle force
operational mobility constraints.
Liquid Propellant Gun
All of the services, including the Army, have explored the use of a liquid gun
propellant. One advantage would be the potential for much lower sensitivity to
accidental ignition, which could reduce the weight and volume of protective packaging
used with current rounds. Another potential logistical advantage over cartridge-loaded
OCR for page 94
94
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
solid propellants is that, in principle, one liquid propellant, transported and stored in
bulk, could be used for all calibers of guns except small arms.
However, there are unresolved storage and chemical issues related to ignition.
For example, using liquid propellants in large quantities on the battlefield would require
new methods of storing, pumping, and replenishing the propellant at each gun tube,
much like distributing fuel to vehicles. A separate succlv vehicle would only add to the
logistics support requirement
rr ~ -a---- ----I
Although the chemistry of liquid propellants has been studied for more than 40
years, the technology is not yet mature. There are major problems, which are still not
well understood, with both chemical decomposition and run-away kinetics when the
propellant is in contact with transition metals. Variability in propulsive performance is
thought to be a function of gun breech temperature. Pressure transients and oscillations
continue to be a problem, and the observed transients have not yet been successfully
modeled.
Significant logistics advantages would result if the ETC gun concept could be
combined with liquid propellant technology. if liquid propellant technology succeeds,
the shell casing could be eliminated, allowing the entire breech to be filled with
propellant. ETC enhancement of muzzle velocity would compound the increase in
projective force for a given breech volume (i.e., gun tube diameter). Thus, the
combination of these technologies has the potential for a synergistic combination of
much greater muzzle velocity for a given caliber of gun and weight of propellant
_ _ _ _ , ,
tclecreased weight per round and decreased system weighty, together with lower
sensitivity of the munition to unintended detonation (which reduces weight and volume
of packaging). Because of these potential benefits, the Army should undertake a study to
see if combining the ETC gun concept with liquid propellants would lead to a
technological breakthrough.
Small Missile Systems for Precision Attack
Small rocket, or jet propelled, missiles are both a battlefield complement to gun-
fired projectiles and a potential replacement for them in meeting some AAN lethality
requirements. This discussion focuses on potential substitutions as alternative means of
reducing logistics burdens for AAN missions. However, the committee expects that the
larger Army of 2025 (AAN forces plus Army XXT forces) will continue to use a number
of complementary systems, both gun tubes and small missiles.
From a logistics standpoint, missiles have an important advantage in precision
guidance, which the committee believes is the most important technological route to
reducing the logistics burden of ammunition weight and volume. Gun tubes have the
traditional advantages of direct-fire and high-fire-rate weapons, as well as a lower
acquisition cost per round and munition weight per round. (A comparison based on total
cost per kill, including indirect logistics burdens for transporting "dumb" rounds in
quantity, will reveal meaningful system trade-offs for AAN.)
The Advanced Fire Support System (AFSS), a current DARPA program for
close-support indirect fire (e.g., artillery accompanying battle force elements, as opposed
to standoff platforms), illustrates the existing missile technology and emerging system
concepts. An example of a potentially competitive "gun-tube" technology is the Marine
Corps Dragon Fire system. The discussion below of these two systems is intended to
OCR for page 95
ENGA CEMENT
95
explore the state of the art and highlight important logistical issues, rather than argue for
or against a general technology (missiles versus gun tubes) or particular system.
For long-range precision artillery, at distances comparable to or greater than
those of the "corps artillery" EM gun concept discussed above, missile technology offers
an obvious potential substitute for gun-tubes. Cost per kill and nontechnical
considerations, such as acquisition competition with other joint-force standoff platforms,
may be important factors in deciding whether to develop one or both of these technology
options.
Missile Systems for Kinetic Energy Attack on Armor
High velocity KEP ammunition can be used to attack enemy armor using
conventional, ETC, and EM gun system technologies, or using missile system
technology. The advantages of missile KEPs are that they can kill at longer ranges, use
larger projectiles, and enable in-flight guidance. A missile system can also be used for
top attack, increasing the potential kill probability against currently configured combat
armor (namely, battle tanks).
KEPs traditionally have been gun-launched using direct-fire aiming, which
limits them to line-of-sight targeting of the front or sides of an enemy tank, which are
usually better protected and harder to penetrate than the vehicle top. However, a ramjet
or rocket could propel a KEP warhead over longer distances (over the horizon), and the
target impact location could be precisely controlled.
A disadvantage of relying on a missile system in close engagements is that a
KEP missile would have to reach a speed of Mach 6 (roughly 2km/s) or more to reach
maximum velocities and establish terminal guidance control. An EM gun system that
could put the same energy on the target repeatedly would be too heavy for a high-
mobility platform. Because of its lighter weight and greater standoff range, the KEP
missile would provide the only feasible approach to meeting AAN engagement system
requirements.
There appears to be no perfect solution (within the time frame for fielding initial
AAN capabilities), and difficult trade-offs will have to be made on the basis of thorough
analyses. The Army, which is currently exploring KEP missile technology in the
Compact Kinetic Energy Missile (CKEM) Program should ensure that this program and
the corresponding work in EM and ETC gun development will produce the data needed
for trade-off analyses, including logistics burdens and other performance measures,
within the AAN decision window.
General Purpose Indirect-Fire Weapons
The AAN battle force will need one or more lightweight, precision-guided
indirect-fire weapons. This requirement meshes well with the intent of the DARPA
AFSS program, which is exploring conceptual weapons systems that combine weight
reductions and ease of deployment with enhanced fire support. The program objectives
of AFSS are to develop and test systems that can provide the rapid response and lethality
of existing gun and missile artillery, enhance system survivability, but require
significantly fewer personnel and less logistics support. The program's tasks include
developing and demonstrating (1) a highly flexible system, including a guided projectile
OCR for page 96
96
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
or munition; (2) a remotely commanded, self-positioning launcher; and (3) a command
and control system compatible with military doctrine.
The system concept on which the AFSS program has focused is commonly
called the Rocket in a Box. This modular rocket system is similar in design to current
multiple launch rocket systems (MERS) but has more firepower, is smaller, has precision
guidance, and has Tower procurement and life-cycle costs. Because it can operate with no
personnel at the container site, it also reduces the need for artillery crews.
The Rocket in a Box design includes four subsystems: Six Pack missiles; a
container-launcher unit; a computer and communications subsystem; and a shipping
container. The full development of the system will require work on launchers, munitions,
seeker-designators, warheads, and guidance and control and propulsion systems. An
attractive feature of this design is that the missiles in their container-launchers can be
fired immediately by remote control ("cold launch"), which makes every "uncrated"
container, whether sitting on a truck, tank, or land site, a potential artillery battery.
Although the charter for the AFSS program seems to cover gun-tube technology
as well as missile systems, the program has focused on the missile artillery option. The
rationale for this choice was not clear from the materials and briefings the committee
received. Presumably it reflects a perception that logistics costs for gun-tube ammunition
and crews are high. The economic advantage, however, is not obvious. For comparison,
the Marine Corps Dragon Fire concept illustrates a gun-tube technology option that has
many of the same advantages for the AAN that the Rocket in a Box has.
Dragon Fire is a robotic mortar system that folds to a mere 18 inches for
transport and can remain hidden in defilade on the battlefield until called into
action by remote command. It then unfolds itself within three seconds to a standing
position, automatically loads its ammunition, and fires. A single gun tube can fire a
variety of munitions (packed in a 32-round magazine), including a munition guided by
the GPS. The 120-mm tube has a range of 13 km with rocket-assisted munitions (Roos,
1998~. Thus, Dragon Fire can provide precision attack capability from a light, portable,
relatively inexpensive platform. A similar system to accompany an AAN battle force
could provide significant logistics savings in ammunition, crew, and transport for both,
compared with traditional crew-served mortar and cannon artillery systems.
Precision Guided Munitions
Whatever launch technology is used, the critical element for hitting the target
with every indirect-fired round is precision guidance of the projectile to its aim point.
The opening section of this chapter on SA described some of the enabling technologies
for precision guided munitions. These technologies can be integrated into different
guidance regimes. In some regimes, the target is identified and tracked, aim-point
control data for the projectile are computed either at the launch platform or at a target
designator located separately from the launch platform, and the projectile and the control
data are transmitted to the projectile. For a fast-moving battle force, however, the most
useful guidance regimes are those that provide "fire and forget" capability. This means
that, at some point during the flight to the target, the components of the projectile itself
take over the functions of acquiring and tracking the target and computing path
corrections.
OCR for page 97
ENGA CEMENT
Squib Fire E\tronics
Acoustic Sensors (4)
Wing Flaps (4)
Main Charge \ - -
~ \
Power Regulator
Altimeter
Infrared Seeker
Impact Fuse Sensor
FIGURE 6-3 Major BAT subsystems.
97
Deceleration and
Stabilization
Subsystem
i\
Curved Tail Fin (4)
'c:'·~' gallery
K~ Air Data Sensor
Electronic Safe and Arm Device
[3^ ~ Control Actuator System
, ~ Central Electronics Unit
~ Inertial Measurement Unit
Precursor
In this section the committee uses the Anny tactical missile system (ATACMS)
and the brilliant anti-tank (BAT) submunition to illustrate how the components of
precision guidance are assembled in a present day "smart munition." The committee
believes that the development of BAT, which began in the early 1980s, is an excellent
example of how technology can be used to provide highly reliable, inexpensive, and
compact munitions that could cut the logistics burden of ammunition to a fraction of
today's requirements. It also illustrates how lengthy the process from conception to
fielding is likely to be for AAN systems.
A BAT can locate, attack, and destroy an enemy combat vehicle, including a
tank. The kill mechanism involves attacking stationary or moving vehicles from the top,
where they are most vulnerable. The BAT airframe, which provides the external
aerodynamic configuration for the submunition, contains all of the subsystems to
perform the terminal-phase functions for homing in on the target (Figure 6-3~. All
necessary location and tactical data are downloaded from the parent missile system to
the BAT submunitions prior to their release. The control actuator system provides the
guidance and control for the submunition, based on control data (commands) from the
central electronics unit, which is the computational focal point for the submunition. The
central electronics unit integrates all sensor data and mission logic and generates the
sequence of computer commands to complete the mission. The computations are based
on mission logic software, inertial measurement data Tom the inertial measurement unit,
air speed data from the air data sensor, and acoustic data from the acoustic data sensors.
A thermal battery provides electrical power for the power regulator, which in turn
supplies and conditions the various electrical voltages required by the BAT subsystems.
After the main missile vehicle releases the BAT submunitions, each BAT
deploys a gas-inflated ram air stabilizer (GTRAS) that stabilizes and decelerates the
OCR for page 99
ENGA CEMENT
99
soldiers who move and fire them.) The general challenge, then, is to develop affordable,
highly lethal systems that can engage a broad range of targets and, at the same time,
reduce the weight and volume of projectiles, missiles, warheads, and launch systems.
The committee identified four areas of improvement in the broad area
of energetic and warhead materials that could substantially reduce logistics burdens:
missile propellants
less sensitive munitions
warhead materials and explosives
multipurpose warheads
In addition to research and development in these specific areas, general enabling
technologies including materials processing techniques and analytical design tools (see
Appendix C) are needed in all areas.
Missile Propellants
For many AAN operations, explosives and propellant materials and formulations
will have to provide higher performance but be less sensitive to shock and thermal
threats. For example, missile acceleration will have to increase dramatically over today's
standards to achieve a relatively short fly-out time, the Mach 6 and higher velocities
required of a missile system roughly equivalent to a gun system for KEP rounds.
Missile propellants for both rocket and air-breathing (iet) propulsion will have to
be throttleable, produce minimum smoke and thermal energy, and be less sensitive. For
an AAN battle force in particular (but also for follow-on Army forces), missile systems
with stealth and agility must be launched from small vehicles next-generation scout or
utility vehicles, as well as AAN combat vehicles.
Solid-fue! ramjet technology uses fuels that are not exotic and uses the air as the
oxidizer (a small solid propellant booster is needed to accelerate up to Mach 2~. High-
speed ramjet missiles could yield high payoffs for a lightweight AAN battle force (see
Figure 6-4~. Ramjet missiles have high velocities (ca. Mach 6), can be as small as
Stinger missiles, and are generally powered all the way to the target. Their range
depends on their size. Above Mach 6, cooling does become an important consideration,
and new materials would have to be used. Current and future generations of ramjets use
gas generator chambers in which the propellant burning rate can be controlled by
chamber pressure, resulting in a throttleable missile. However, new propellants will have
to formulated that have a broad range of burning rates at safer low pressures to prevent
the ramjet from exploding.
The primary benefit of using air-breathing engine cycles in Army missile
systems is the increase in propulsive energy over conventional rocket systems. This
increased energy can be used to extend range or decrease time to target (or a
combination of the two), to decrease the number of launchers required, to provide
throttle control to enable "smart" propulsion, and to decrease missile size and weight
while maintaining performance levels.
Solid-ducted ramjets reduce maintenance, and liquid-fuel ramjets are available
for extended high-speed cruise. Turbine engines are presently in use for long-range
subsonic flight. The solid-fuel Air-Turbo-Rocket combines a simple expendable turbine
OCR for page 100
100
2
1.5
_`
~1
-
F
0.5
o
FIGURE 6-4 Comparison of engine technologies.
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
1
¢
Turbojet
Relative Engine Cost
and Risk
~ ,
Ramjet ,, .'
~ At'
J
J
- ~ ' ~ Scramjet
1
1 1 1
0 2 4 6 8
Speed (Mach number)
with a ramjet combustor to attain subsonic to supersonic speeds, while maintaining
throttle control. For high-speed systems, ramjet engines could upgrade existing missile
systems for a fraction of the cost of a new weapons development program and
substantially improve performance. Air-breathing engines can be expected to increase
the propulsion unit cost by 20 to 100 percent over rocket propulsion. However,
considerable savings can be expected at the system level, considering propulsion
typically represents on 5 to 10 percent of the missile cost. Other cost factors include
reduced procurement quantities because of improved coverage and reduced material
losses.
Fifteen years ago, many U.S. companies and the armed services were all
working on ramjets. Today, only two U.S. companies have expertise in ramjets and,
perhaps, only one military program is still active, the Beyond Visual Range Air-to-Air
Missile (BVRAAM). In fact, the United States could lose all of its capabilities in this
area, even though several foreign countries (Russia, United Kingdom, China, France,
India, South ADica, Germany, Israel, and Japan) have ramjet missile systems, active
flight testing, or ongoing development programs.
The Army is participating in the Integrated High Payoff Rocket Propulsion
Technology (THPRPT) Program to improve rocket motor performance dramatically.
IHPRPT is a cooperative effort of government and private industry, with joint service
participation. Its goal is to develop a strategy for doubling U.S. rocket propulsion
performance in the next 15 years. Novel propellants and ingredients, higher pressure
operating conditions, and multipuise and throttleable motors are all being considered.
The committee believes that increased participation in this program, particularly with a
clear focus on the needs of AAN systems, would be a good way for the Army to leverage
its resources to reduce AAN logistics.
OCR for page 101
ENGAGEMENT
Warhead Materials
101
The purpose of improving warheads for shaped charges and explosively formed
penetrators is to increase the lethality of warheads. Promising materials for the mass
element of the shaped charge or penekator include tantalum, molybdenum, and tungsten.
These elements can be coupled with energetics in precise formulations to ensure "one
hit, one kill" while decreasing the weight per round. As a prime example, shaped charge
performance is strongly influenced by the precision of the explosive. Lethal performance
can be increased by improving precision for a fixed energy.
Multimode Warheads
A multimode warhead can produce one of several compact, controllable pattern
fragments, depending on the target type. For example, these warheads can be pro-
grammed in the field to deliver a single explosively formed penekator (top attack on an
armored vehicle); large chunky fragments (vehicles and other targets); or high blast with
very fine fragments (antipersonnel and blast-sensitive targets). To reduce the logistics
burden and increase versatility, the Arrny should continue to support basic work on
multimode warheads.
Advanced computerized detonation models are an essential aspect of this
research. The Logistics Integration Agency provided the committee with an overview of
relevant work at several U.S. Department of Energy national laboratories (Chase, 1998~.3
In 1994, for example, the Los Alamos National Laboratory reported that it had
developed metastable interstitial composite energetic materials with the potential for
tailored reaction rates with product gas conkoT that could enable warhead fragmentation
patterns to be "tuned to achieve a kill while minimizing collateral damage." These
materials could lead to smaller and more lethal warheads that reduce logistics burden.
Smaller, highly efficient warheads could also be launched from robotic vehicles, such as
UAVs or UGVs.
Less Sensitive Munitions
Decreasing the sensitivity of energetic materials and formulations is a difficult
technical challenge because increasing the performance of a material as an energetic has
historically tended to increase its sensitivity. However, if artillery rounds, warhead
explosives, and missile propellants were less sensitive to impact and thermal exposure,
they would not only be safer to handle, but they would also reduce logistics burdens.
The most important direct consequences in terms of reducing logistics burden
would be that packing densities could be increased, the amount of protective packaging
could be reduced, and bulk shipping would be less complex. Because less sensitive
munitions have less risk of fratricide, fewer rounds would explode accidentally during
storage, movement, and handling. Box 6-1 describes the results of a Navy study
indicating that the indirect effects on material costs could be substantial, in addition to
reducing the risk of death and injuries.
3 Much of the work in this area is classified.
OCR for page 102
102
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
BOX 6-1 Benefits of Less Sensitive Munitions
The Center for Naval Analyses has studied the effects of insensitive munitions on board
aircraft carriers (CNA, 1991~. Actual data on deaths, injuries, and materials costs for three
accidents (on three carriers) in which no insensitive munitions were involved were compared
with the center's estimates if the best existing technologies (at that fume) for reduced
sensitivity had been in use.
Actual Estimated
Consequence (no insensitivity) (insensitive) Reduction
Deaths 176 72 59%
Injuries 552 63 89%
Materials Costs $1,966.50 $469.60 76%
(1999 $ million)a
aReported cost data for fiscal year 1991 increased at 4 percent per year to fiscal year 1999.
The absolute numbers for three incidents may not carry over from Navy to Army
environments; aircraft carriers are much more expensive than Army combat platforms, and
the personnel density aboard ships is very high. Nevertheless, the percentage reductions
indicate that even with 1991 technology, which has since been improved significantly, less
1 =
There are many ways the Army could decrease the sensitivity of its munitions,
even with current technologies. Many Army warheads still use either pressed HMX
(high melting explosive) (up to 98 percent) with a binder or melt-cast explosive
formulations, such as Composition B (RDX trapid detonating explosive] and TNT
t2,4,6-Trintrotoluene]) or Octo! (HMX and TNT). All of these formulations are much
more shock sensitive then improved formulations and will detonate when exposed to
shocks of 14 to 28 kbar. Figure 6-5 illustrates the roughly threefold decrease in shock
sensitivity attainable by replacing these formulations with existing PBX (plastic-bonded
explosives) that have the same performance characteristics as energetics.
The Large Scale Card Gap Test on which data in Figure 6-5 are based uses a
standard apparatus and procedure prescribed by Naval Ordnance Laboratory Technical
Bulletin 700-2. A donor charge that produces a known shock pressure is detonated
against the explosive to be tested. If the donor charge detonates the test explosive when
in direct contact with it, cellulose acetate cards of a standard thickness (0.01 inch) are
placed between the donor charge and the test explosive. Each card attenuates the shock
pressure by a known amount, represented by the curve in the graph. The point on the
curve where a given explosive formulation is detonated but at which one more card
causes no detonation, is the score for shock sensitivity in this test. For the test results
illustrated, conventional Arrny warhead explosives had test scores of 14 to 28 kbar. PBX
alternatives had test scores of 50 to 69 kbar. (Bernecker, 1988~.
Beyond the substantial improvements that could be made simply by adopting the best
current technologies, the development of improved energetic s must be recognized as a
system design problem. Army missile propellants and explosives will have to be less
sensitive to both temperature and shocks and have higher specific energy (energy per
unit mass and volume) and other performance values. In decreasing the sensitivity of
munitions, many factors will come into play. Shock sensitivity is usually reduced
OCR for page 103
ENGA CEMENT
320
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
o
103
\~ Cards a
¢ :Current Warhead Fills
I'
POX Warhead Fill
Replacements
~11 1 1 1 1 1 1 1
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105
Pressure (kbar)
a 1 card = 0.010 inches
FIGURE 6-5 Calibration curve from large-scale card gap tests of conventional warhead
explosives used by the Army and PBX replacements. Source: Bemecker, 1988.
through changes in formulation and Processing techniques. Reductions in thermal
O a ~ a ~ ~
. . . .. . . . . . . . . . . .
sensitivity usually require soph~shcated changes in engineering design of the to
configuration and casing to provide adequate venting under either slow or fast heating
rates. Energetic s performance and sensitivity to diverse threats must be considered in the
context of increasing the accuracy of targeting through precision guidance and SA.
Smokeless rocket propellants are being developed today that have increased
specific impulse but are less sensitive to shock. Plastic-bonded explosives dramatically
reduce shock and thermal sensitivities. For example, the Air Force warhead explosive
AFX-235 has the performance characteristics of an explosive that contains 96 percent
(by weight) HMX, although it contains only 75 percent HMX in an energetic plastic-
bonded binder. Shock-sensitive weapons or munitions could be more closely spaced by
the clever use of mitigating materials (closely related to the development of armor
materials) and by unique packaging layouts based on computerized shock models.
Thermal threats could be mitigated by active or passive venting. The Navy has
implemented a variety of concepts for less sensitive munitions, including the strategic
use of barriers and mitigators. The Army, however, has only begun to recognize the
logistical (and safety) implications of reducing munitions sensitivity.
In terms of logistics burdens, more rounds can be stored in the same area if they
are less sensitive, or an equivalent number of rounds (or equivalent amount of lethal
force per projectile) can be stored in a smaller area. Platforms and operations can be
designed to allow personnel and equipment to operate in closer proximity to ammunition
stores. The chances of transportation or handling accidents would be reduced, as well as
the logistics and operations planning margins, and the safety of Arrny personnel would
be increased. If the AAN process forces the Army to design for the best systems
solutions for achieving diverse performance goals, including substantial reductions in the
logistics burdens of ammunition and lethal systems, the Army will have a golden op-
portunity to make decreased munitions sensitivity a serious cost trade-off.
OCR for page 104
104
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
Logistics Implications of Projectile Weapon Systems
The foregoing discussion has only touched on the surface of potential system
and application concepts, their potential logistical consequences, and the technological
opportunities and issues relevant to providing projectile weapons for an AAN battle
force. Even this limited review, however, demonstrates that there will be no obvious
winners among the alternative systems. In many instances, data are not sufficient to
make quantitative comparisons, particularly with respect to the logistical implications of
an entire weapons system concept. Should an AAN "main combat vehicle" be armed
with an ETC gun, an EM gun, or an improved missile system? Which alternative has the
least logistics burden for an implementation that could be in the field by 2025? Would a
general switch to liquid propellants meet AAN engagement needs while reducing
logistics burdens? Which approaches to precision guidance will guarantee that every
round hits its target? The answers to these and other questions will be required to support
design decisions that must be made by 2010, ~5 years before the AAN becomes a reality.
The general argument advanced in Chapter 3 for a systems engineering approach to
logistics trade-off analyses will be crucial for selecting new projectile weapons for AAN.
Current Army and joint programs run the gamut of research and development in
the technologies for projectile weapons. Except for some of the electronics for enabling
precision guidance, nondefense commercial markets will not take the lead or be a source
of innovation. However, the Arrny can leverage the R&D program base in projectile
weapons that already exists. The goal of many of these programs was, and still is,
increasing lethality, not reducing logistics burdens. Fortunately, "one round, one hit, one
kill" has substantial implications for both. But these programs have different
constituencies responding to different requirements. Even for nonIogistical performance
objectives, there are no common criteria for program success. The Army should try to
coordinate resources from these programs for trade-off analyses of AAN engagement
systems.
First, the Army will have to formulate the questions about AAN performance
capabilities that must be answered in teems that apply to the candidate projectile weapon
systems. These performance capabilities must include logistical performance as a
primary objective, not as an afterthought. Second, each existing program that supports a
weapon system concept must be evaluated to determine whether, and in what time frame,
it might provide answers-or the data needed to mode! solutions that will provide the
answers to those questions. Finally, the Army should make adjustments to programs to
ensure that answers will be available in time for AAN decisions on system designs. In
many cases, existing concept demonstration programs will have to be modified to ensure
that they provide sound data on logistics support requirements that can be fed into
platform models and engagement models in the M&S hierarchy described in Chapter 3.
If the current state of knowledge cannot support a technical basis for acquiring essential
data empirically or for constructing a validated simulation to model it, the Anny might
have to support applied or even basic research.
DIRECTED ENERGY WEAPONS
Directed energy weapons, which use electromagnetic radiation as their lethality
mechanism, include laser, high-power microwave, and high-power millimeter wave
systems. Because their lethality mechanism is the transfer of energy from this radiation
OCR for page 105
ENGAGEMENT
105
to the target on which it is focused, there is no mass or volume of ammunition, as there
are with projectile weapons. Instead, the logistics burdens are the fuel and energy to
supply the high power demands of these weapons, the weight and volume of the pulsed
power subsystem that stores and transfers electrical energy, and the weight and volume
of the subsystem that creates and directs the pulses of radiation at the target. For
weapons systems that accompany an AAN battle force to the area of operations, the
energy needed to recharge the pulsed power storage subsystem must be supplied by the
battlefield fuel carried with the battle force or by some other store of energy, such as
primary batteries. The conversion of fuel energy to electrical energy for the weapon
power supply must be included in the sizing of the system that does the conversion-
most likely the power plants in combat vehicles.
Barring an unanticipated paradigm-altering discovery about the fundamental
physical mechanisms on which directed energy technologies are based, the committee
believes the position stated in the STAR 21 study remains valid. in the AAN time frame,
directed energy weapons will be feasible options as tactical systems for antisensor,
antiprecision guidance, and anti-SA weapons. It will not be feasible to develop directed
energy weapons systems for heavy-duty structural attack, particularly for the highly
mobile operational concepts envisioned for an AAN battle force. The STAR 21 report
predicted that "heavy-duty directed energy weapons for vehicle kill against aircraft,
missiles, and spacecraft are likely to develop first, if at all, as strategic defense systems"
(NRC, 1992, p. 86~.
Transportable versions of directed energy systems, probably developed for the
defense of the continental United States, might eventually be usable in an AAN staging
area, if adequate energy were available and if the battle force operation was vulnerable
to antisensor and anti-SA weapons. From the standpoint of reducing logistics burdens for
an AAN battle force, however, tactical directed energy weapons would complement and
supplement projectile weapon systems, not replace them. Therefore, they represent a
separate and additional class of logistics burdens.
Lasers
Various types of lasers have potential as offensive weapons against small and
large protected targets, but they would require very high power densities and durations
on target, as well as a direct line of sight to the target. The Night Vision Electronic
Sensors Directorate of the Army Communications-Electronic Command (CECOM) has
defined a notional directed energy warfare vehicle (DEW-V) that could serve as a
"virtual test-bed" to determine the operational effectiveness of vehicle-mounted directed
energy weapons for battle scenarios in 2015 and beyond. Although there is no hardware
development plan, the concept may be expanded to include development of a DEW-V
around an Abrams tank chassis or a Bradley fighting vehicle chassis for Army XXI
(Knowles, 1996~.
Because lasers use discrete wavelengths (primarily in the IR region), care must
be taken to avoid wavelengths that can be degraded by atmospheric conditions. For
example, the Navy stopped work on its high power deuterium fluoride laser because the
laser could not accommodate extreme environmental conditions (Knowles, 1996~.
A more practical use for lasers and other electromagnetic radiation beams,
achievable in the near term, is to use them as antisensor weapons to disable the enemy's
sensors and defend against enemy projectile weapons. The electro-optical sensors used
OCR for page 106
106
REDUCING THE LOGISTICS BURDEN FOR THE ARMY AFTER NEXT
for precision guidance of smart munitions are vulnerable to laser attack. Tactical lasers
that can put energies on the target of more than ~ k] are feasible. Tactically useful free-
electron lasers (FELs) in the megawatt power range may be possible, although to date
only low-power FELs have actually been built (Knowles, 1996~.
One disadvantage of using lasers, even as tactical antisensor weapons, is the
political and geopolitical ramifications of their use. Because they can cause permanent
eye injury, lasers have been banned by international treaty agreements. Because current
electro-optical sensors are also vulnerable to laser attack, both the CECOM and the
Natick Research, Development and Engineering Centers have been working on notch
filters to protect human eyes and electro-optical sensors from the discrete wavelengths
used by lasers.
The principal enabling technologies for laser weapons are efficient high power
generators, efficient lasers, infrared sensors, and advanced processors and target
extraction algorithms (DoD, 1998a). All of the services, and many of the national
laboratories, are currently conducting research on lasers. The Air Force in particular has
an extensive airborne laser program. The committee recommends research groups
involved in these programs coordinate to leverage resources and avoid wasteful
duplication. For a laser antisensor weapon to be incorporated into AAN combat vehicles.
the power requirements for the laser and the sizing of the weapon system will have to be
known before the Army can make realistic estimates for modeling its vehicle design (see
Chapter 5~.
Microwave Devices
Smart weapons that depend on electronic components for precision guidance are
vulnerable to high-power electromagnetic energy that overheats these components to the
point of breakdown. Therefore, directed energy weapons are prime candidates for
defensive applications. The effects of high-power microwaves (HPM) on electronics are
similar in this respect to the electromagnetic pulse (EMP) from the detonation of a
nuclear warhead, except that the HEM frequency range (0.5 to 100 GHz) is significantly
higher. These microwaves can penetrate electronic systems either through the target
system's antennas or through energy leakage into electronics enclosures. With its high
frequencies, HPM can destroy electronic components that would not be affected by a
nuclear EMP pulse. HPM weapons could disrupt or damage communication systems and
the electronic subsystems of weapon systems, smart munitions, and airborne or ground
vehicles.
HPM could also affect friendly forces. For example, stealth coatings are
designed to absorb microwaves, and an HPM pulse could have a thermal effect much
like the effect of a microwave oven. Another drawback of HPM weapons is that the
antennas will have to be large and located in the enemy's line of sight. These antennas
have a significant EM signature, which would make them easy for an opponent to find
and attack (Herskovitz, 1993~.
High-power millimeter wave (HPMM) systems also appear to have great poten-
tial. In short-range engagements (2 to 5 km), the power densities at the target would be
almost the same as at the antenna. An advantage of millimeter waves over laser systems
is that they can be used under a wider range of weather conditions. Progress continues to
be made in the development of HPMM generators. The principal enabling technologies
for HPMM weapon systems are efficient power sources, HPMM generators, precision
OCR for page 107
ENGAGEMENT
107
large antennas, advanced passive electromagnetic sensors, and advanced processors and
target extraction algorithms (DoD, 199Sa).
LESS-THAN-LETIIAL WEAPONS
Like today's Army, the AAN will face a wide array of adversaries. With "less-
than-lethal" (LTL) weapons, the battle force would be able to make a measured response
to an attack or provocation, facilitate the control of opposing forces, and avoid collateral
casualties in situations, such as urban warfare. These objectives are very different from
the objectives of destroying opposing forces with projectile weapons, which have the
unfortunate side effect of harming noncombatants who happen to be in their effective
range. LTL weapons include sticky foams, stun guns and bombs, bright-light flashes,
and rubber bullets that can temporarily incapacitate opponents. Other techniques for
controlling populations are disrupting communications and degrading infrastructure.
Much of the technology development for less exotic LTL weapons has been led by the
U.S. Department of Justice and civilian law enforcement agencies, mainly for crowd
control or for use by special teams in hostage situations.
A unique LTL approach with applications to urban warfare may be to capitalize
on resonances with the human body. For example, the resonant frequency of a human
chest cavity is about 20 Hz, and the frequency of brain waves is between ~ and 40 Hz.
Matching those frequencies "resonantly" with a high-energy source could instantly
incapacitate someone. A prototype pulse detonation engine has a frequency of about 15
Hz. The sound power level from this engine is extremely high-on the order of bets,
rather than decibels, and resonant coupling with brain waves could seriously impair an
adversary. A war-fighter would not have to be in the area of the conflict for this device
to be effective.
Like directed energy weapons, LTE weapons are likely to complement and
supplement projectile weapons rather than replace them. Therefore, they will often add
to logistics burdens by increasing the numbers and variety of systems required in the
battle force's inventory. However, logistics efficiencies could be achieved by including
logistics considerations in the design and development of LTE weapons.
SCIENCE AND TECHNOLOGY INITIATIVES TO REDUCE
LOGISTICS BURDENS OF ENGAGEMENT SYSTEMS
Based on the preceding analyses of the logistics burdens assoc
iated with
engagement system options for AAN battle force operations and the technological
opportunities for reducing these burdens, the committee concluded that the Army should
pursue the following areas of scientific research and technology development. The order
of the numbered items under a heading reflects a rough order of priority.
Situational Awareness
I. Continuation of SA Technology Insertion beyond Army XXI. Technologies that
support near-perfect, near-real-time SA will be critical enablers for AAN engagement
systems. The direct and indirect consequences of ensuring SA range from enabling
effective support from standoff platforms, being able to deliver "just the right amount"
OCR for page 108
108
REDUCING THE LOGISTICS BURDEN FOR THE ARMYAFTER NEXT
of logistics, and the right-sizing of battle force elements to providing the battlefield
intelligence required for "one round, one hit, one kill" precision in indirect-f~re
engagements. SA will thus be the single most significant determinant of both AAN
combat effectiveness and the reduction of logistics burdens.
Rapid innovations in the underlying technologies, most of which will continue to
be driven by commercial market forces beyond the control of the military, will provide
opportunities for improving SA but will also force the performance levels to rise
continually for maintaining technological overmatch against potential opponents. The
Army should not assume that "digitizing" the Army XXT force, through introduction of
today's (or even the next decade's) state-of-the-art technology for information
acquisition, processing, distribution, and representation, will suffice for the AAN in
2025. To ensure that AAN battle forces always have superior SA, the Arrny will have to
find ways to upgrade the underlying technologies incrementally, within resource
constraints, while maintaining system integrity.
2. Precision Guided Munitions. The precision guidance of projectiles (or other
weapons effects, such as directed energy or LTE weapons) is the primary means of
reducing the ammunition logistics burden. This burden has traditionally been second
only to fuel in the weight and volume required per unit of combat effectiveness. As the
battle space defined by lethal reach expands spatially but shrinks in time, precision
guidance technologies will determine how well a force can effect "one round, one hit,
one kill." Much of the information on state-of-the-art technologies and research to
improve guidance systems is classified and, therefore, not available for this study. The
committee assumes that the Army will continue its support of precision attack systems
for the AAN.
3. Vulnerability of SA to Cascading Failure. A weakness or flaw in the technology on
which SA depends could have catastrophic consequences if the system is vulnerable to
single-point failure-or even to multiple-point failure. The commercial markets that
drive many of the core technologies for SA subsystems and components can tolerate
more vuinerabilities than the Army and the national defense generally. To the extent
that SA elements are joint systems, the Army should encourage, and even demand, joint
efforts to ensure that the AAN battle force is not defeated because of an SA failure
stemming from a flaw in a communications network, computer operating system, or
other technology built from commercially developed components. The same rigor will
be necessary for SA elements developed and controlled by the Army. During AAN war
games, the Army should allow the opposing forces to attack SA infrastructure and
should mode! the failure of different SA elements to uncover vuinerabilities.
Projectile Weapon Systems
1. Logistics and Performance Trade-off Analyses for Projectile Weapons. The
committee found no clear, obvious winners among the potential alternative technologies
for the main armament of an armored AAN combat vehicle or close-support artillery.
Even on the level of broad technology options, such as liquid propellants, the available
information is insufficient to make an informed choice, either on the basis of logistics
burdens or trade-offs in which logistics is included with other performance
characteristics. To remedy this situation, the Army should leverage the existing research
OCR for page 109
ENGA CEMENT
109
and development program base in projectile weapons and supporting technologies to
obtain data for modeling system alternatives and making well grounded trade-offs. Data
on logistics burdens should be among the required data about each enabling technology
or system concept. By assessing disparate programs and developments from the
standpoint of their contributions to the hierarchical simulation of system options and
making informed design trade-offs, the Army will be able to determine where
modifications or additions to the science and technology base should be made.
2. Systems Design Approach to Increasing Lethality of Energetics and Warhead
Materials while Decreasing Weight, Volume, and Sensitivity. The most important
enabler for reducing the logistics burden of ammunition (after precision guidance of
munitions) is to increase (or at least maintain) lethal effectiveness per round while
decreasing the total logistical weight and volume per round. The complexity of the
issues, diversity of performance objectives, and broad range of technological
opportunities will require a systems design and trade-off approach to achieve the best
combination of technology for AAN needs. For example, the Army needs missile
systems that are small and affordable enough to be incorporated into large numbers of
smaller vehicles. The missile propeliantts) for such systems must enable higher
acceleration, minimum smoke, less sensitivity to shock and thermal threats, and
capability for precision guidance (i.e., controllable burn rate). New energetic materials
and formulations must increase energy (or rate of energy release) per unit mass and
volume of propellant or warhead explosive, while making the munition less sensitive.
More effective warhead materials and multimode warheads can increase lethal
effectiveness by ensuring that each hit is a kill. As the Army looks for ways to focus and
strengthen its program to improve energetic s and decrease their sensitivity, it should
attempt to leverage the very active Navy program in this field.
Directed-Energy and Less-than-Lethal Weapons
1. Directed-Energy Weapons to Supplement, Not Replace, Projectile Weapons.
The committee agrees with the STAR 21 study, which predicted that tactical directed-
energy weapons would not be feasible for heavy-duty structural attacks on opposing
platforms, weapons, or missiles and projectiles in the 2025 time frame. The logistics
implications of these weapons-in terms of system weight and energy requirements-
also preclude their consideration as weapons for an AAN battle force. However, tactical
directed-energy weapons that can attack sensors, guidance subsystems, and electronic
components are likely to be ready and useful for AAN operations. These tactical
weapons would supplement, but not replace, projectile weapons. Their logistics burdens,
therefore, constitute a separate class from those of projectile weapons.
2. Less-Than-Lethal Weapons to Supplement Projectile Weapons. LTL weapons
for use in special situations, such as urban warfare, or for incapacitating opposing troops
will be another supplement to the AAN engagement arsenal. From the standpoint of
logistics burdens, however, they are not an alternative to projectile weapons.
Representative terms from entire chapter:
battle force
