Copyright 1984 American Institute of Aeronautics and
Astronautics, Inc.;
All Rights Reserved
Aerospace America

August, 1984

SECTION: DEFENSE: SPECIAL SECTION -- ADVANCED WEAPONS; Pg. 62

LENGTH: 2448 words

HEADLINE: Fire-and-forget tactical missiles

BYLINE: By Richard DeMeis, Associate Editor

HIGHLIGHT:
Autonomous weapons reduce risk for the user and could be more effective to
boot

BODY:
	"Fire-and-forget," also known as "launch-and-leave" or "shoot-and-scoot,"
depending on who is pulling the trigger, refers to weapons that need no further intervention once 
fired.  Thus a target need not be "designated" by a laser, which would expose the designator 
during the weapon's flight, or be "painted" by a launching aircraft's radar, which would limit the 
pilot's maneuverability.  Use of vulnerable data links between the launcher and a
missile is also reduced.  Although long-range missiles from ballistic to
antiship types are autonomous, only recently have similar shorter range systems b
een designed at a reasonable cost.  Integrated-circuit microelectronics and
small, strap-down gyro sets allows packaging of the required guidance and
control into the smaller volume of such weapons.

   The AIM-120A Advanced Medium Range Air-to-Air Missile (AMRAAM) is the most
prominent of this new generation since it will give beyond visual range,
fire-and-forget radar weapons to all U.S. fighters and many allied aircraft, andi
s therefore a high volume, big money program.AMRAAM is also farthest along in
development.  But, in the opinion of a program manager familiar with this
technology, the greatest change may not be in the air-to-air arena but in
surface-to-surface Army antitank missions.  He contends that although AMRAAM
will allow the launching aircraft to engage other targets and defensively
maneuver, the aircraft is otherwise no less visible than before.  Munitions ablet
o home onto tanks independently let the Army conceal the launcher better or
avoid exposing a footsolider or helicopter for standoff designating.  Other
measures, such as PRVs and rotor mast-mounted sights can reduce these hazards
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mewhat.  The Army is developing several fire-and-forget weapons ranging from
shoulderlaunched to the millimeter-wave radar seeker-equipped Terminally Guided S
ub-Munition (TGSM), which will be dispensed against massed armor at ranges up
to tens of kilometers in a "six-pack" from Vought's Multiple Launch Rocket
System (MLRS) mother-vehicles.  Contract for the NATO-deployed TGSM will be
awarded this September to one of several teams made up of U.S. and European
companies.

   Not entirely fire-and-forget, Assault Breaker completed demonstration in late1
982 but is now on hold due to cost.  The weapon could augment MLRS/TGSM
effectiveness with its longer range.  Whereas MLRS is fired unguided and uses
the greater detection range of the TGSM's mm-wave seeker, Assault Breaker would b
e guided to the target area by its JSTAR (Joint Surveillance Target Attack
Radar) aircraft.  Once in the target area, the submunition's shorter range IR
seekers would then take over.

   Since the Army and Air Force agreed in late May that the former's
responsibility would extend to 70 km behind enemy lines, vehicle configuration
can now be decided.  The Dept. of Defense had proposed either a modified Patrioto
r Lance, designated T-16 or T-22, respectively for their diameters in inches asth
e mother vehicle.  T-22 has a range up to 120 km and T-16, over 100 km.  Both can
 carry 20 subminitions.  However, the Army may elect to use another
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hicle.  Assault Breaker could be fielded by the end of the decade.  Most
useful in target-rich situations, weapons such as MLRSs and Assault Breaker are m
eant to get the field commander out of them.  As another wag puts it, "General Cu
ster had a targetrich environment."

   Millimeter-wave and infrared technologies are also being applied to guide
mortar and cannon projectiles against individual, mobile targets that get
through the MLRS screen.  The previously mentioned manager also cautions againstu
sing the improved ability to package processing onboard a vehicle to better
performance -- driving up costs -- rather than to increase autonomy.

   Similar views were expressed by a former Air Force general involved with
developing air-to-ground weapons.  He cited the cancelled Wasp missile, with itsd
esirable, workable features, mainly its ability to lock-on to a tank target
after launch, as a cost driver making the system too expensive.  Though he
recognizes Maverick as effective in close air support, he believes it becomes
cost ineffective if used to take out a truck in the rear echelon.  Maverick
would have been even more expensive if it did not lock-on to the target before
launch.  This requirement can expose a launch aircraft to ground fire when a
weapon's boresight is narrow and necessitates poppingup and turning the airplanet
o point almost directly at the target before firing.  The latest imaging IR
version of the Maverick can have its seeker slaved to an aircraft-mounted
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w-altitude navigation, targeting infrared for night (Lantirn) pod eliminating suc
h a prelaunch restriction.  But here again the general cites initial "over
specification" on the Lantirn pod to distinguish between different types of
targets, trucks, and tanks, rather than just simply identifying target arrays,
as forcing the program above cost and behind schedule.

   The general also mentions the development of low-cost strap-down gyros for
inertial navigation, which permit off-boresight launches and target acquisition a
fter launch and reduce targeting updates to the weapon in flight.  Using these on
 the proposed Low-Altitude Dispenser System would allow off-boresight release of
the free-fall weapon to deliver several Skeet munitions against an array of
tanks.  The IR-sensing Skeet's self-forging, shaped-charge warhead is sufficientt
o penetrate the light armor above the tank's engine.  These gyros also give thela
test version of the GBU-15 glide bomb similar launch freedom against
stationary, hard point targets.

   One Dept. of Defense official feels the issues regarding future weapons are
not necessarily technical.  "We can make a weapon do essentially what we want,
but can it be cheaply mass-produced?  As of now, the military is not convinced. A
nd because of the expense, the uniformed services cannot try them out enough tobu
ild up confidence in them."
 Another perspective on fire-and-forget philosophy is given by Chuck McKinley,Vou
ght's vice president of Hypervelocity Missile Systems.  While admitting the
question of fire-and-forget for air-to-air combat is somewhat different due to
the presupposed exposure of the launch aircraft and the necessity to engage
several enemy fighters, in the ground attack case, he argues, it is not often
affordable for the results obtained.  Locking on target before launching
alleviates cost, but, McKinley asserts, "fire-and-forget must be considered in
the overall context of system survivability to see if it is increased at a
reasonable cost." He sees guidance and short flight time to target as other
factors in the survivability question and poses an interesting example: "Supposea
 high-energy mobile laser can be developed.  With accurate pointing it can
instantly destroy a target.  It is certainly not a fire-and-forget weapon but iss
urvivable and effective by accuracy and speed of kill.  Backing down from the
speed of light there should be a range of fast, accurate missiles that can
approach such effectiveness at a reasonable cost."

   Although the value of ground attack fire-and-forget is subject to debate, thec
ase is clear for air-to-air.  AMRAAM is the only game in town.  When its
predecessor, the AIM-7 Sparrow, was developed in the 1950s vacuum tubes were thec
ontemporary technology.  It was not possible to cram a satisfactory
flight-weight transmitter and receiver into the missile.  The solution was a
semiactive seeker -- the launching aircraft would illuminate the target with
                                                                               it
s radar and the receiver on the missile would pick up the energy reflected
from the target.  Based on combat experience, Sparrow has been improved through t
he '60s and '70s with new motors, shorter minimum range for better dogfighting,se
ekers that can find a target in ground clutter, and other such improvements.
But the necessity to maintain target illumination by the launching aircraft
became unacceptable on the grounds that any future conflict will likely be
fought against greater numbers.  Any aircraft unable to engage several targets
at once would have an inherent disadvantage.

   Microelectronics permit an active seeker, both transmitter and receiver, to
be packed into AMRAAM's front end so it can attack targets independent of the
launch aircraft's radar.  A smaller strapdown gyro package provides adequate
inertial guidance over typical aircraft to target distances.  The AMRAAM seeker i
s turned on near the anticipated position of the target.  This combination
actually makes the AMRAAM a "dual mode" missile or fire-and-sometimes-forget
bird.  If, for instance, during the inertial portion of flight the launch
aircraft radar's tracking functions show an evasive target maneuver, then targetp
osition updates will be transmitted to the missile via the fire control radar'slo
w-power sidelobes.  Against active countermeasures, AMRAAM can home on the
jammer and during close-in combat can go directly to active seeker.  The seeker a
ntenna is gyro-stabilized to minimize its accelerations and thus improve targettr
acking.  The missile is designed to be launched at any aircraft flight
                                                                               co
ndition.

   The realm of short-range dog fighting has already been improved to allow
all-aspect engagement, attack from any quarter, with the latest IR-guided AIM-9 S
idewinder variants that are just pointed at a target by the maneuvering
aircraft.  Once locked on, Sidewinders are fired and forgotten.  AMRAAM will
extend the improved intercept zones to beyond visual range, on the order of
20-30 km, and permit firing against multiple targets.  Once AMRAAM is fielded,
further advances in the short-range arena will come about with the European-led d
evelopment of the more maneuverable, IR-homing ASRAAM (Advanced Short-Range
Air-to-Air Missile) to replace Sidewinder.

   Improved radar-guided missiles demand effective Identification, Friend or Foe(
IFF), to allow their use without any "artificial" rules of engagement or visualid
entification.  The enemy does not wait for daylight and fair weather.IFF can
be effected, either actively with encoding transponders or passively by radar orI
R signature.  Eyeball identification can also be extended via such techniques
as the F-14's long range TV.

   Hughes is now in the 31st month of a 50-month AMRAAM full-scale development
contract leading to deployment on the F-16 in 1986.  The first of 87 production c
onfiguration development missiles will be rail launched from an F-16 this
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nth.  There was concern over the health of the electronics and gyros during
ejection from existing Sparrow launchers.  The forward ejector-piston foot is
positioned in these areas on the F-14 and F-15.  Hughes feels this should not bea
 problem since it has been designed for it and analysis and ground firing pit
tests have borne this out.  Other testing has included captive test flights to
measure carriage loads and vibration, and aeroelastic effects of a launcher on
the F-16 wing tip.  Missile electronics have also been flown in separate
airborne tests.  When asked about progress, Quade Hansen, Hughes assistant
AMRAAM program manager, said that so far "there have been no show stoppers," andt
he most difficult part in getting the missile out in the field has been the
tight development schedule.

   Other AMRAAM features include a small wing for low-speed lift for maneuveringa
t extreme range or right after launch during dogfights.  Hansen said Hughes
would have preferred a larger delta wing such as Phoenix's, but has to fit
within Sparrow's geometric envelope for carriage on existing aircraft.  Still
the wing design gave results close to those expected from the longer-chord deltap
lanform.  Low-smoke propellant is used in the rocker motor to decrease
detection of missile firing and flight.  Some impulse is lost because of the
deletion of aluminum oxide from the propellant to reduce smoke but is offset by i
mproved aerodynamics over Sparrow, including smaller wings and body diameter, 7vs
. 8 in., for lower drag and lighter weight, 327 lb vs. 514 lb.  Reliability
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d maintainability are obtained by features such as the use of electric tail
control actuators instead of hydraulics.  Hansen noted that the cost of
hydraulic performance was weight, complexity, and leaks, and that samarium
cobalt motors of adequate size and performance, about 1 hp, were also available.
   In addition to fitting within Sparrow's geometry, AMRAAM had to have the
maximum degree of compatibility with existing launching aircraft fire control
systems.  Electronic compatibility called for aircraft "software" changes and
multiplex "sharing" of the aircraft's transmitters.  The missile has built-in
test and checkout features to insure the pilot of an "all-up" round.  For rail
firing AMRAAM it was necessary, however, to design a dual launcher that could
carry AMRAAM's weight and also be used for Sidewinder.  The existing Sidewinder r
ail was not strong enough to bear AMRAAM loads under all conditions and, in
addition, would have required removal of the missile's forward "button" used fora
ttaching Sparrow to ejection launchers.  The ejection launchers only needed
changes to the ejection foot contours to accommodate the smaller diameter
missile.  Analysis is underway to determine if any ejection cartridge changes ors
ystem porting is needed for AMRAAM's lower weight and inertia.

   AMRAAM will undoubtedly follow Sparrow in being modified for sea and ground
launch.  Its fire-and-forget benefits can then be used for multiple launches
against multiple targets without depending on a shipboard or groundbased
                                                                               ta
rget illuminator.

   AMRAAM has not been without its controversies.  The published cost of
$340,000 per missile, over three times that of a Sparrow, has been criticized.
It may not reach initial operational capability in 1986 -- no tactical versions h
ave yet flown.  With the first tactical AMRAAM not due to fly until this month,pr
oduction quantities may be ordered before testing is complete.  The Air Force is
anxious to get AMRAAM fielded as soon as possible to make the F-16 an
all-weather fighter.  Navy Support in some quarters is restrained, with periodict
alk of Sparrow upgrades to an active seeker with tail control, perhaps saving
development funds, since the F-14 and F-18 already can carry this radar guided
missile.

   Despite controversy, AMRAAM will likely become the premier
beyond-visual-range radar-guided weapon for NATO fighters through the 1990s.
And hopefully, fire-and-forget antitank weapons will have also contributed to
raising the nuclear threshold in Europe.