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George McAllister, Principle Manager

Asymmetric Threat Technologies

June 11-14, 2007

Pic

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George McAllister, Principle Manager

Asymmetric Threat Technologies

June 11-14, 2007

IED P

roble

ms

IED P

roble

ms

•A prominent feature of IEDs currently used by enemy forces

against U.S. forces in Afghanistan and Iraq is their roadside

application in attacking vehicle convoys.

•Terrorists continue to build devices that have destroyed our

most powerful conventional warfare systems –Abrams

tanks and Bradley fighting vehicles –for a very small

investment in time and materials.

•Over 50% of the casualties in OPERATION IRAQI FREEDOM

are a result of IED attacks.

•While much has been done to provide our warfighters with

improved body arm

or, up arm

ored HMMWVs, and CREW

systems, the problem of concussion injury and damage

remains.

Reference: The Asymmetric W

arfare Group: Closing the Capability Gaps, Lt. Gen.

James J. Lovelace Jr. & Brig. Gen. Joseph L.Votel, Arm

y Magazine, March 2004

Concussio

n I

nju

ries

Concussio

n I

nju

ries

•Almost 18,000 troops have been wounded according the

Department of Defense. The VA doctors say that two-

thirds of them have been injured by IED blasts and two-

thirds of those exposed to blasts suffer some brain injury

--ranging from a mild concussion to perm

anent

damage. Brain injuries -–

thousands of them –-could be

the legacy of this war just as much as post-traumatic

stress and problems from exposure to Agent Orange

persisted among many of the troops who served in

Vietnam*.

•As early as 2004, when Arm

y doctors examined soldiers

wounded in Iraq, they found 62% also had undiagnosed

concussion injuries.

* Reference: Center for Brain Injury Recovery

What is

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What is

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e?

•Pickett's Charge is a counter-concussion active

protection system.

–Pickett’s Charge is not intended to replace

existing defensive counter-measures, such

as arm

or.

–Rather, it is meant to supplement existing

defensive systems allowing them to work

more efficiently, saving lives and reducing

vehicle damage.

Phenom

enolo

gy E

xplo

ited

Phenom

enolo

gy E

xplo

ited

•Basic physics –

Wave inte

rfere

nceis the

phenomenon which occurs when two waves

meet while traveling along the same medium.

•Can intentional concussion waves be used to

interfere

or counterthe effects of IED blast,

concussion and fragmentation…

–Using directional explosive charge employed on

a moving vehicle to deflect, degrade, and/or

counter the effects of blast and fragmentation

hazards produced by an exploding enemy

roadside IED?

•The theory is sound and the physics does work.

How

Does P

ickett

’s C

harg

e W

ork

?

How

Does P

ickett

’s C

harg

e W

ork

?

•Pickett’s Charge operates in the time interval

between IED initiation (no matter how the device

is initiated) and the time that the destructive force

reaches the targeted vehicle or personnel.

•Although this time interval is short, it is sufficient

for operation of a counterm

easure consisting of

ultra-responsive pressure transducers, high speed

initiation systems, and shaped charges.

Deto

nation P

ressure

sDeto

nation P

ressure

s

•High-order explosives detonate quickly, generate heat and

fill the space with high pressure gases in 1/1000thof a

second producing a supersonic overpressurizationshock

wave that expands from the point of detonation which

moves outward in a pressure pulse.

•This "blast wave" (positive wave) moves in all directions,

exerting pressure of up to 700 tons. At the point of

detonation, this overpressurizationcauses the surrounding

displaced air to form

a small pressure spike. The displaced

air then compresses and form

s a vacuum returning to the

point of detonation (negative wave).

Bla

st W

aves

Bla

st W

aves

•The small pressure spike of compressed-

displaced air moving out in front of the main

overpressure is the secret to Pickett’s Charge.

Com

pre

ssed

Dis

pla

ced A

ir

Negative

Pre

ssure

W

ave

Main

Bla

st W

ave

Overp

ressure

Peak P

ressure

Puls

e

Dura

tion

Basic

Syste

m D

escription

Basic

Syste

m D

escription

•A fast-reacting sensor, capable of sensing/detecting the

front of an oncoming pressure wave from an IED

detonation, is mounted on the outside of a vehicle. Upon

sensing this pressure wave, a directional counter charge is

fired within microseconds (theoretically, nanoseconds). This

directional counter charge, operating similar to the

Explosive Reactive Arm

or, serves two distinct functions:

1.The counter charge’s outgoing pressure wave would

theoretically intersect, offset, and deflect the oncoming

pressure wave thus reducing the impact of shock waves on

the vehicle and personnel.

2.The counter charge could also theoretically propel a mass at a

velocity greater than the roadside IED detonation velocity that

would significantly intercept, deflect, and/or reduce the

Translational Kinetic Energy of fragmentation from the

oncoming IED, (including EFPs) resulting in reduced blast

pressure and lower kinetic energy fragmentation.

Pic

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esig

nPic

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n

•Pickett’s Charge is designed to provide a controlled

directional counterforce to enemy IED attacks. It is

designed to be small and easily installed. Once the

mounting hardware and wiring is in place, replacement of

an expended Pickett’s Charge can be accomplished by the

vehicle operator as a snap-in replacement.

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•Damping is designed and built into the charge mounts,

which remain perm

anently affixed to the vehicle and can

be swapped out in the field. The charge itself is designed

to be a snap in unit so that it can be installed quickly

when needed for convoy operations or other missions.

This maintains simplicity in field maintenance by

removing the need to accomplish vehicle alterations

each time the charge is installed.

Pic

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echnic

al

Analy

sis

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echnic

al

Analy

sis

•We analyzed the timing of a typical IED in theater versus

the timing of Pickett’s Charge.

–Pressure transducer response time on the order of

microseconds

–Detonator will fire with several microsecond responses

–Recommend the use of high speed discrete logic to reduce

latency time

•Included in the analysis were the parameters at which

pressure waves can be detected. Pickett’s Charge is

feasible and can react in sufficient time to intercept IED

blasts.

Tim

ing F

easib

ility G

raphic

Tim

ing F

easib

ility G

raphic

4.26 us

3.2 us

2.2 us

0 sec

.2 us = Pressure sensor rise reaction time

1 us = Capacitor discharge time to fire EFI

1.06 us = Complete function time of RP-97 EFI

T-0 Start of Pickett’s Charge detonation

2 us = Typical time for the

blast overpressure to reach peak pressure

6.26 us

2 us

2 us for the electronics slope detector

Blast & Fragmoving from IED towards Target Vehicle

0 sec

200 us

300 us

302 us

100 us = Typical time for a bridgewire

electric detonator to completely

function and initiate the primary explosives

T-0 Start of IED

detonation

200 us = Typical time an M6

blasting cap bridgewire can

heat up to 300ºC the point when the

solid bridgewire turns to a molten gas

2 us = Typical time for the

blast overpressure to reach peak pressure

Point of detection/start of the firing of Pickett’s Charge

33.8 us per foot with HMX PC

PC pressure wave moving from vehicle towards IED

50.8 us per foot with Enemy HME

*all times are in

Microseconds

Com

parison o

f Com

ponents

and

Tim

e F

acto

rs

Com

parison o

f Com

ponents

and

Tim

e F

acto

rs

Typic

al IE

D C

om

ponents

and

Tim

e F

acto

rs

•200 us = Typical time an M6 Blasting

cap bridgewire can heat up to 300ºC

with a 12volt power supply. *300ºC is

the point when the solid bridgewire

turns to a molten gas

•100 us = Typical time for a

bridgewire electric detonator to

completely function and initiate the

primary explosives with <50 VDC

•2 us = Typical time for the blast

overpressure to reach peak pressure

•50.8 us per foot for HME detonation

velocity and pressure wave velocity

(6000 m/sec)

Pic

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om

ponents

and

Tim

e F

acto

rs•

.2 us = Pressure sensor rise reaction

time using PCB PiezotronicsModel

134A pressure sensor

•2 us = Electronic time for slope

detector to determ

ine not only that a

threshold value has been reached but

that it has been reached in a certain

time period to minimize false triggering

of Pickett’s Charge

•1 us = Capacitor discharge time for

firing EFI detonator

•1.06 us = Complete function time of

RISI RP-97 Explosive Foil Initiator

•2 us = Typical time it takes for the

blast overpressure to reach peak

pressure

•33.8 us per foot for HMX detonation

velocity and pressure wave velocity

(9110 m/sec)

Burd

ens

Burd

ens

•Weight

–Weight of the perm

anently affixed hardware is

estimated to be approximately 20 lbs or less,

depending on the material of the springs.

–Weight of shaped charge and packaging should

be less than 2 lbs.

•Power Requirements

–Will be powered from vehicle power system.

–Detection electronics will draw minimal power

(milliamps).

–Detonation circuit will utilize pre-charged

capacitor.

Fra

tric

ide C

onsid

era

tions

Fra

tric

ide C

onsid

era

tions

•Considerations

–Vehicles equipped with Pickett’s Charge would have

to operate with the same considerations as existing

vehicles equipped with reactive arm

or.

•Issues

–Pressure measurement sensitivity must be optimized

to avoid inadvertent initiation.

–Can incorporate secondary blast detection techniques

such as rate of temperature change.

–Safeties to prevent fratricide

–An automatic safety system tied to vehicle movement

–Control panel within the vehicle compartment to allow

disabling of the system in friendly areas

–Use of energetic material such as C4 assures material stability

Safe

ty a

nd C

ert

ific

ation I

ssues

Safe

ty a

nd C

ert

ific

ation I

ssues

•System should be HERO tested to ensure safe operation

in the presence of communications equipment and other

RF emitters

•Should have a minimum of double (triple preferred) fault

tolerance to prevent against inadvertent detonations

•Charge with detonator should be certified to withstand

static discharge

•Should be tested using the following specifications as

guidance:

–MIL-STD-237C, Electromagnetic Environmental Effects and

Spectrum Certification Guidance for the Acquisition Process

–MIL-STD-461E, DOD Interface Standard Requirements for

the Control of Electromagnetic Interference Characteristics

of Subsystems and Equipment

Technic

al/

Ris

k I

ssues a

nd

Pla

nned E

ngin

eering S

olu

tions

Technic

al/

Ris

k I

ssues a

nd

Pla

nned E

ngin

eering S

olu

tions

•How does Pickett’s Charge address inadvertent firing?

–The threshold of the pressure sensor is set to 80-100 kilobars,

much higher than norm

al pressure anomalies. W

ill also utilize

pressure change rate determ

ination and potential temperature

rate of change.

•How does Pickett’s Charge address possible firing towards

friendly vehicles?

–Through a selectable control panel mounted in the vehicle the

operator can check continuity and arm

or disarm

the desired or

undesired mounted charges, as well as use a command detonated

feature to breech roadblocks.

•How does Pickett’s Charge address the possible firing in the

event the vehicle is not in tactical convoy mode?

–Either through the control panel if vehicle is running, or through

disengagement of sensors and firing circuit when the vehicle is

shut off.

Technic

al/

Ris

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ssues a

nd

Pla

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ngin

eering S

olu

tions

Technic

al/

Ris

k I

ssues a

nd

Pla

nned E

ngin

eering S

olu

tions

•What is the recommended tactical employment of Pickett’s

Charge?

–The lead vehicle should have the front-mounted and both flank

mounted charges arm

ed. Every third vehicle beyond that should

have the two flanked charges arm

ed. The last vehicle should have

both flank charges arm

ed and a rear-mounted charge arm

ed.

Charges should be replaced after counter charge employment.

•How does Pickett’s Charge address the recoil and back blast of

the counter charge?

–Through innovative recoil dampening and arm

or protection.

•How does Pickett’s Charge get mounted / remounted?

–Mounting will be in a quick disconnect fashion. The arm

or shield

will be perm

anently affixed to the vehicle, with the actual counter

charge and sensors attachable. Connect the counter charge and

connect the electrical connection, start the vehicle, clear the area

and test continuity. For replacement, disconnect the spent counter

charge electrical connection, remove spent counter charge

housing, replace new counter charge assembly, connect the

electrical connection, start the vehicle, clear the area and test

continuity through control panel.

Perf

orm

ance M

etr

ics

Perf

orm

ance M

etr

ics

•Should be able to counter an IED explosive

blast over 50 kilobars at 2 inches or greater

distance.

•Response time of Pickett’s Charge should be

less than 5 microseconds (theoretically –

nanoseconds), including detonation.

Conclu

sio

ns

Conclu

sio

ns

•Pickett’s Charge physics support the concept.

Within 4.26 us after a pressure wave is

detected, Pickett’s Charge can be deployed.

•As long as Pickett’s Charge can detect the

pressure wave within a conservatively sufficient

~ 2 inches away from the vehicle, Pickett’s

Charge can be fired and intercept the IED blast

wave. (For HME the distance required for

pressure detection is 1 inch to allow sufficient

time to fire Pickett’s Charge.)

Questions???

Questions???

Back-u

p s

lides

Back-u

p s

lides

Thre

ats

Addre

ssed

Thre

ats

Addre

ssed

•Pickett’s Charge is a directional counter charge

intended to interact against multiple IEDs

simultaneously. With a counter charge effect

working against the oncoming effects of the

IED, the existing protective measures of the

vehicle and personnel arm

or would have

improved survivability characteristics against:

–Blast

–Concussion

–Fragmentation

“As we’ve improved our armor, the enemy’s improved his IED’s”-Major Simmons, Army National Guard

RIS

I RP-9

7 E

FI

Deto

nato

rRIS

I RP-9

7 E

FI

Deto

nato

r

•RP-9

7 S

eale

d E

FI

Deto

nato

rP/N

188-7

399

•The RP-97 Exploding Foil Initiator (EFI) is a medium cost

detonator designed for applications where an EBW

detonator is not acceptable.

•RP-9

7 F

IRIN

G P

ARAM

ETERS

–Thre

shold

Voltage: Approx. 1350 volts with 0.25 µFD

Capacitor

–Thre

shold

Voltage S

td. Devia

tion: 50 volts maximum

–Function T

ime: Approx. 1.06 µsec

PCB P

iezotr

onic

sPCB P

iezotr

onic

s

•M

odel134A

Tourm

aline pressure bar, 10k psi, 0.12 pC/psi, charge

output, 0.2 µS rise time (reflected shock wave)

•Measurement Range: 10000 psi(68950 kPa)

•Sensitivity: (±15%) 0.125 pC/psi(0.018 pC/kPa)

•Temperature Range: (Operating) -32 to +120°F (-36 to

+49°C)

•Electrical Connector: 10-32 Coaxial Jack

•Weight: 0.98 oz (28 gm)

Explo

siv

e D

eto

nation V

elo

citie

sExplo

siv

e D

eto

nation V

elo

citie

s

EXPLOSIVE

DETONATION

DENSITY

SENSITIVITY

VELOCITY

PRESSURE

m/sec

kilobars/psi

HMX

9110

390/5656472

1.89/pressed

Moderate

LX-10

8820

375

1.86/pressed

Moderate

LX-09

8810

377

1.84/pressed

Moderate

PBX-9404

8800

375

1.84/pressed

Moderate

RDX

8700

338

1.77/pressed

Moderate

PETN

8260

335

1.76/pressed

High

Cyclotol

8035

-1.71/cast

Low

Comp B 63/36 7920

295

1.72/cast

Low

TATB

7760

291

1.88/pressed

Very Low

PBX-9502

7720

-1.90/pressed

Very Low

DATB

7520

259

1.79/pressed

Low

HNS

7000

200/2900755

1.70/pressed

Low

TNT

6640

210/3045792

1.56/cast

Low

*HME

6000

-cast

Low

Baratol76/24 4870

140

2.55/cast

Moderate

Boracitol60/40 4860

-1.55/cast

Low

Plumbatol70/30 4850

-2.89/cast

Moderate

*HME= Home made Explosives (used by insurgents in Iraq) reference JIEDDTF

** Table referenced from LANL

Los A

lam

os N

ational Labora

tory

Peak O

verp

ressure

Los A

lam

os N

ational Labora

tory

Peak O

verp

ressure

Experim

enta

l pre

ssure

fro

m 3

.63-k

g

Pento

lite

cylinders

at 0.3

048 m

heig

ht of

burs

t vs. experim

enta

l tim

e a

t a test-

scale

depth

of 0.3

m a

nd test-

scale

range o

f 0 m

is

2 m

icro

seconds.