American Institute of Aeronautics and Astronautics

1

Extraction and Separation Modeling of Orion Test Vehicles with ADAMS Simulation

Usbaldo Fraire Jr.1 Jacobs Engineering, Houston, TX, 77058

Keith Anderson2 ATK Brigham City, Utah 84302

P.A. Cuthbert3 NASA-Johnson Space Center, Houston, TX, 77058

The Capsule Parachute Assembly System (CPAS) project has increased efforts to demonstrate the performance of fully integrated parachute systems at both higher dynamic pressures and in the presence of wake fields using a Parachute Compartment Drop Test Vehicle (PCDTV) and a Parachute Test Vehicle (PTV), respectively. Modeling the extraction and separation events has proven challenging and an understanding of the physics is required to reduce the risk of separation malfunctions. The need for extraction and separation modeling is critical to a successful CPAS test campaign. Current PTV-alone simulations, such as Decelerator System Simulation (DSS), require accurate initial conditions (ICs) drawn from a separation model. Automatic Dynamic Analysis of Mechanical Systems (ADAMS), a Commercial off the Shelf (COTS) tool, was employed to provide insight into the multi-body six degree of freedom (DOF) interaction between parachute test hardware and external and internal forces. Components of the model include a composite extraction parachute, primary vehicle (PTV or PCDTV), platform cradle, a release mechanism, aircraft ramp, and a programmer parachute with attach points. Independent aerodynamic forces were applied to the mated test vehicle/platform cradle and the separated test vehicle and platform cradle. The aero coefficients were determined from real time lookup tables which were functions of both angle of attack (α) and sideslip (β). The atmospheric properties were also determined from a real time lookup table characteristic of the Yuma Proving Grounds (YPG) atmosphere relative to the planned test month. Representative geometries were constructed in ADAMS with measured mass properties generated for each independent vehicle. Derived smart separation parameters were included in ADAMS as sensors with defined pitch and pitch rate criteria used to refine inputs to analogous avionics systems for optimal separation conditions. Key design variables were dispersed in a Monte Carlo analysis to provide the maximum expected range of the state variables at programmer deployment to be used as ICs in DSS. Extensive comparisons were made with Decelerator System Simulation Application (DSSA) to validate the mated portion of the ADAMS extraction trajectory. Results of the comparisons improved the fidelity of ADAMS with a ramp pitch profile update from DSSA. Post-test reconstructions resulted in improvements to extraction parachute drag area knock-down factors, extraction line modeling, and the inclusion of ball-to-socket attachments used as a release mechanism on the PTV. Modeling of two Extraction parachutes was based on United States Air Force (USAF) tow test data and integrated into ADAMS for nominal and Monte Carlo trajectory assessments. Video overlay of ADAMS animations and actual C-12 chase plane test videos supported analysis and observation efforts of extraction and separation events. The COTS ADAMS simulation has been integrated with NASA based simulations to provide complete end to end trajectories with a focus on the extraction, separation, and programmer deployment sequence. The flexibility of modifying ADAMS inputs has proven useful for sensitivity studies and extraction/separation modeling efforts.

1 Aerospace Engineer, Aeroscience and Flight Mechanics Section, 2224 Bay Area Blvd, Houston, TX, AIAA Member. 2 Aerospace Engineer, Advanced Engineering, P.O. Box 707, Brigham City, UT. 3 Aerospace Engineer, Aeroscience and Flight Mechanics Division, Houston, TX.

https://ntrs.nasa.gov/search.jsp?R=20130011078 2018-06-30T22:39:26+00:00Z

American Institute of Aeronautics and Astronautics

2

Nomenclature A = Airborne Aref = Reference Area AESM = ADAMS Extraction and Separation Model AGL = Above Ground Level Cx = Force aerodynamic coefficient associated with the direction Cxx = Moment aerodynamic coefficient associated with the direction

CDT = Cluster Development Test cm = Center of Mass cp = Center of Pressure Downdraft = Design variable with range of 2500±2000 lbs; dispersed during a Monte Carlo analysis. EDU = Engineering Development Unit Fa = Axial Drag Fn = Normal, up and down Fy = Side to side IMU = Inertial Measurement Unit Lref = Reference Length Mll = Moment about the roll axis Mm = Moment about the pitch axis Mln = Moment about the yaw axis

= Dynamic Pressure Rho = Atmospheric density.

= Extraction parachute apparent drag area as a function of time. Vex = Velocity of the extraction parachute. Vm = Magnitude of the extraction parachute velocity Vmated = Velocity of the mated CPSS/PTV cg. Vz = z-component of the extraction parachute cm velocity vector

I. Introduction NDERSTANDING the physics, dynamics and force interactions during extraction and separation events between an aircraft, test article, and platform are vital to the success of a Capsule Parachute Assembly System

(CPAS) test campaign. Aerodynamics, atmosphere, vehicle configuration, mass properties, and the force interactions between these objects are key components that must be considered when designing for a drop test. Optimizing test vehicle mass properties to support end-to-end flight stability is critical, but a vehicle separation solution is necessary to initiate a favorable deployment sequence. Without a good separation solution, the CPAS drop test campaign would be at increased risk of loss-of-test-vehicle (LOTV) malfunctions during deployment.

The first test of a fully integrated CPAS system, Cluster Development Test 2 (CDT-2), occurred during the Generation I testing phase. The configuration consisted of a capsule shaped vehicle called a Parachute Test Vehicle (PTV) mated to a Cradle and Platform Separation System (CPSS). The approximately 30,000 lbs mated vehicle was extracted using a C-17 aircraft at an altitude of 25,000 ft. The CDT-2 test resulted in a LOTV due to a programmer deployment malfunction that occurred during the initial stages of flight after the PTV/CPSS separation event1. Valuable test experience was gained from this effort that is implemented in subsequent flights. To provide insight to the force interactions of test articles during the intricate extraction and separation flight phases, the development of the Commercial off the Shelf (COTS) tool Automatic Dynamic Analysis of Mechanical Systems (ADAMS) was employed. Efforts were invested to model the extraction-separation event of CPAS test articles based on physics principles versus qualitative solutions or assumptions.

Since the test execution of CDT-2, three successful Engineering Development Unit (EDU) capsule tests have been performed. EDU-A-CDT-3-3 was the first baseline capsule test after the CDT-2 mishap. The ADAMS Extraction and Separation Model (AESM) was used as the primary tool to provide nominal and Monte Carlo trajectories from aircraft extraction to PTV/CPSS separation through PTV programmer deployment. The state vector of the PTV in the AESM was delivered to Decelerator System Simulation (DSS) as initial conditions to provide predictions through vehicle touchdown. The preflight predictions were comparable to the flight test data. Post-test data reconstructions identified a delay in the cut command signal when the smart separation parameters

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ar each other, tic effects indu

ntation d on the side og exceeds the ltatic line lengthment bag are tw22 lbs) is oins the The four

gs which points on are 198.8 3 inches. gs exceed

from the ependent attached

continues length of deployed. h Figure the time rammer at linein the section f

V. Data Recextraction and

ue and did not force interactioft forces.

o Separation

f Aeronautics a

7

M simulation hource not fountakes place th

est articles chans independent

he surfaces of tcket on the CPS

the front bumpuce a moment a

of the PTV untlength of the sh has been excwo masses, on

stretch to be ufor extraction p

construction d separation evprovide the sa

ons, system eve

Figure 1

Figure 11

and Astronauti

helped us deternd.. he following snge from the m6 DOF object

the release meSS and mainta

per slide along about the PTV

til the distancestatic line connceeded, the Prone weighing 51

used for calculparachute infla

Results vents were per

ame separation ent cut triggers

10: Interactiv

1: Programme

ics

rmine the con

sequence of evmated propertiets, Figure 9. A

echanism in theains about the s

the heat shieldV cm to keep th

e between the necting the twoogrammer beco.6 lbs represen

lations of the pation.

rformed for Esolution. Ther

s, vehicle attitu

ve Forces duri

er Inflation Se

ditions of the

vents and interes to the indepeAs the mated v

e form of a balsame pitch and

d of the PTV, Fhe PTV rotatin

attach points o markers togetomes its own 6nting the mass

programmer in

DU-A-CDT-3-re were deviatiude and day of

ng Release

equence

Smart

ractive endent vehicle

ll-and-d pitch

Figure ng in a

on the ther as 6 DOF of the

flation

-3 and ions in f flight

A. AvioniA time

and CPSSovercome time delaythe PTV/Cseparation.was includconditions

B. ExtracA clust

C. ExtracAction

The exaction (EFexerted trisers and Extraction attach poinThe pre-tEFLA waground at

FigureActivat

Figure 14

ics Time Delaye delay or time

S, respectivelyinternal interf

ys was the impCPSS vehicles a. To account fded in the smwere satisfied

ction Parachutter of two 28

ction Force

xtraction forcLA) is the tenshrough the suspension linParachutes

nt on the matetest orientatioas set horizonextraction. Up

12: Avionicsted by Pin-Pu

4: Reduced CEfficiency

Figure 16:

Americ

y e lag observed

psrtPcoc

CTs

. The ball aference prior toplementation oand allowing bfor the known mart separation

and execution

te Inflation Mft Extraction P

madecalcureconwas reducextraphaseinteraclust

Line of

ce line of sion that is simulated

nes of the about the

ed vehicle. on of the ntal to the pon further

System ll at RC

Cluster

Downdraft F

can Institute of

in measured fpreflight predisensors to mearigged pin-pulltest reconstructPTV/CPSS sepcut command tobserved avioconfiguration

CPSS. The release mesocket geometand socket into complete sep

of an AESM reball/socket inteavionics time n logic to all

n of the cut com

Modeling Parachutes aree for modelingulated withounstruction resureduced 15% ced due to cluaction parachue due to interaction can be ster efficiency a

Force Variatio

f Aeronautics a

8

flight test dataictions. The asure time, pitcl mechanism attion comparisoparation criterito the pyrotech

onics time delshown in Figu

echanism is cotry which is iterfaces requirparation. A release mechanerferences to oclag a conservalow for proce

mmand signal.

e simulated as g the drag forut consideratioults confirmed

in a cluster ouster parachuteute did not infrference and cseen in Figure re the aircraft w

Figure 15

on

and Astronauti

a was evidentlyon-board CPS

ch, pitch rate pt the ramp cleaons identified tia on a delay dhnic cutter syslay was attribure 13 that is

omprised of a binstalled on thre additional result of the onism geometry ccur prior to a

ative 90 ms timessing time on

a composite prce produced bon of clustethat the extrac

of two. The e interactions dflate to full opcrowding relat 14. Other facwake, which is

examinatideterminebetween tinitial oscof the papredicted for EDU-respective

The pCDT-3-5

5: PTV Attitu

ics

y missing comSS avionics syparameters andar event as seenthat the avionic

due to processinstem. Anothbuted to the used to secur

ball and he PTV time to

observed joining

a cleared me delay

nce the

parachute. Thby dual extracer efficiency.ction parachutmagnitude of

during the inflpen during thtive to one anctors that contrs currently not

ion of the moed there is athe EFLA and cillation. The allet at the ram

by a magnitu-A-CDT-3-3 anely as shown inost-test video vEFLA appear

Fi

ude Dynamics

mpared to the Aystem includesd are activated n in Figure 12.cs system sensng and executi

her contributor release mech

re the PTV on

he initial assumction parachute However,tes cluster effi

the drag forcation process.

he chaotic extrnother. This cribute to the redirectly quanti

del behavior, a direct correthe amplitude downward pitcmps edge wasde of 30% andnd EDU-A-CDn Figure 15. verified the ED

red oriented low

igure 13: RelMechanism

s

AESM s IMU with a Post-

sed the ing the to the

hanism nto the

mption es was data ciency

ce was Each

raction cluster educed ified.

it was elation of the

ch rate s over d 60%

DT-3-5

DU-A-wer in

ease m

relation wextraction the extractconverges downward relative to the first mapplied forplane. A nthe extracti

The dovalue set tpositioned A-CDT-3-As the dowmagnituderelease has

D. VehiclePredictin

instantaneothe AESMEDU-A-CDthe actual mforces exp

intended toapproach wbounding dynamics tin the AESexperienceramp clearaltitude wa

The MCtrajectory solution thmalfunctioextraction/preflight MCDT-3-7 oconsidered

Figure

with the ramp parachutes a n

tion parachute behind the aithan the no wthe ramp plan

motion of the mr a one second nominal peak vion parachute d

owndraft force o 2500 lbs. Eeither over an5 produced a

wndraft force inof the pitch ra

s proven to be e

e Dynamics ng vehicle dynous separation

M with represenDT-3-3. Data measured true

perienced betw

o cover all thewas implemenextreme attituthat could be sSM at ramp cled in test by ther were 3.5˚ anas set to ±500 fC capability pvariations and

hat required saon risks /separation phMC predictiononly entered thd a satisfactory

e 17: Vehicle

Americ

plane comparnew variable netravels in the w

ircraft in the rwake airflow. Tne. It is appliemated vehicle o

duration eithevalue for the codrag force is

seen in the twEach test had dnd under or sidgood match toncreases, the mate was differenexceptional.

namics and theof bodies to m

ntative initial ccomparisons airspeeds. The

ween the CPSS

e C-130A andnted to averagudes and ratesseen when extrlear. Post teste C-17. The acnd 2.0˚/sec, resft. provided insigd introduced a afeguarding to

during hases of flightns prior to Ehe Smart Separy solution if th

Acceleration

can Institute of

ed to EDU-Aeeded to be intwake of the airegion of the

The downdraft d in the simulaon the aircraft r pushing the e

omposite drag

wo flight tests wdifferent extrace by side as se

o the measuredmagnitude of thnt during the in

e time sequenmodeling interconditions was showed that the slower flight

S pallet and C-resulted forces b

A Mounknowparametband foparameton-boardincluded

conservati[0˚-10˚] pi

d C-17 data exge the aircraft . This approacting from a Ct analysis demctual C-17 aircspectively. A

ght into unique reduce

the t. All

EDU-A-ration Windowhe PTV pitch r

C‐1

f Aeronautics a

9

A-CDT-3-3, Figtroduced in thercraft, there is extraction paraforce is used toation as a timeramp. As the

extraction paraforce is about

was 800 lbs anction parachuteeen in Figure 1d test data as she pitch and pitnitial descent o

nce of the initirnal force inter

the first lessohe preflight pret test extraction-17 ramp. Th

in a faster eetween the pal

V.onte Carlo (M

wn trajectory tyters. To initialr the aircraft rters were defind C-130A andd due to limitive dispersion ditch and [0˚/s-xperience. Th

flight test pitoach delivered C-17. The foll

monstrated that raft pitch and pll other mass

w (SSW) from rate at separat

17 Aircraft Init

Ramp Pit

Ramp Pitc

Table 2

and Astronauti

gure 16. In e AESM and w an airflow thaachute, drivingo control the pe step functione PTV/CPSS isachutes below, 39,000 lbs. Th

nd 4100 lbs, ree orientations. 6. The 4100 lshown in Errotch rate will deof the payload

ial phases of fractions. The on acquired durediction reachn of the PTV/Che initial AESMextraction sequllet and ramp im

Monte CarMC) capabilityypes that couldlize the MC anramp pitch an

ned using a limd C-17 aircrafted availabilityderived from t10˚/s] pitch ra

his proved to btch and pitch

d a more reprelowing criteriathe derived d

pitch rate valueproperty inert

the maximumtion was above

tialization Para

tch Angle (⁰) 

ch Rate (⁰/sec)

2: Ramp Initi

ics

order to vary was called the dat streamlines g the extractio

position of the n that is activats extracted, thin-line, or slig

he equation for

espectively wit The orientati

lbs downdraft or! Referenceecrease. For E, but the overa

flight has evounderstandingring the post ted the end of

CPSS was a conM assumed nouence. The amproved the ex

rlo Analysis y was develod be triggered analysis a reprend pitch rate wmited test data sft sensor tray.y of C-17 onthe diverse dataate band. The be too conservrate values a

esentative dispa were used to dispersion bandes seen during tias were dispe

m pitch rate side 0˚/sec and h

ameter  Min

0

0

ialization Para

the position downdraft forcover the aircraon parachute fextraction parted 1.2 seconde downdraft fo

ghtly above ther the z-compon

th the nominalon for each teforce used for

e source not foEDU-A-CDT-3all timing of th

lved from assg of how to initest reconstructthe ramp fastensequence of co frictional lo

addition of fricxtraction timin

oped to analyzwith a unique esentative disp

was required. set acquired fr C-130A dat

nly data. An a points resultedispersion banvative and a s

at ramp clear persion band initialize the a

d captured whaEDU-A-CDT-

ersed ±10% an

de. A MC cychad a α ≥ 95˚.

nimum  Maxi

0.0  5

0.0  5.

ameters

of the ce. As aft and further achute

ds after orce is e ramp nent of

(5) l input

est was EDU-

ound.. -3, the e PTV

suming itialize tion of er than contact ss and ctional ng.

ze the set of

persion These

rom an ta was initial

ed in a nd was second versus of the

aircraft at was -3-5 at nd the

le was This

imum 

5.0 

.33 

requiremenparachute tdraft forceclassificati(MaxPR), Minimum progressivesupported conditions identify toutside the

A new observed wforce and aconditions SSW fromtrajectory attributed 4300 lbs cinputs beloramp initibelow 1, sUnder thesapex forwaby the oraseparationsapparently points.

The secoforces asso

slope of thacquired aassumptionThe SSW command 18. Earlier AEattributed tare activatfor EDU-A

Figure

nt helped oppoto recover conte variable traions of trajecto

Minimum Pitch Angle

ely been ancanalysis effothat produce

he possibilitye defined SSW

trend of Mwith the implavionics time dnow could pot

m the MinPR anclass that entewith having oupled with raow 2˚ and 1˚/salization paramsuch as a 0.7se conditions, iard at separatio

ange case shows. This scenarimotionless, un

ond novel trajeociated with its

he accelerationand implementn of instantaneevent was nowsignal event th

ESM predictioto the delays ined, a period of

A-CDT-3-5 wa

e 19: TrajectoSeparati

Americ

ose any apex fotrol authority oansformed howories. Each traPitch Rate (MinPA). T

hored to testorts to disclose unfavorabley of trajectousing MC anaonte Carlo trementation of

delay. Trajectotentially enter

nd MinPA windered the MinPdowndraft fo

amp pitch and sec, respectivemeters usually˚/sec pitch ratif the MinPR won with high ri

wn in Figure 1io orients the Pntil the force o

ectory class whs inputs. The r

n curve. An uted in the AEeous separation

w split into twohat is executed

ons have moden the separationf time has passas approximatel

ories Entering ion Window

can Institute of

forward attitudeof the vehicle aw AESM trajajectory class i(MinPR), an

The AESM hat data and hase the physicae attitudes anries separatin

alysis. rajectories waf the downdraories in the righthe non-optimadow. The nove

PR window waorces exceedin

ramp pitch rately. One of thy had an inpute or 0.4˚ pitcwindow was seisks of snaggin9. Extreme d

PTV as it sits oof the inflating

hich entered thramp initializa

understanding ESM. Acquirinn and was rep

o visible featura delta time af

eled higher pin event. From sed resulting inly 10˚/sec. Th

the Smart

f Aeronautics a

10

e at separationand re-orient hejectories enteris defined by t

nd as as al

nd ng

as aft ht al el as ng te he ut ch. et too low, sucng lines and tudowndraft forceon the CPSS wprogrammer p

he MinPA wination inputs we

window. Ththan 2˚ aninitialization pitch and pishield forwaresults. Casusceptible executing thSSW. Thisacceleration time lag. Treaching theseparated anConversely, the SSW codecelerate u

of the systemng an insight tplaced with a sres, a trigger evfter the system

itch rates at sewhen the cond

n different pitche predicted sep

F

and Astronauti

n and allowed eat shield forwred the SSWthe SSW plane

ch as at 0˚/sec,umbling withoues also produc

with an α=90˚ aparachute is ap

ndow, like the ere contributorshe MinPA rampnd 2˚/sec, re

values affecteitch rate at exard PTV attituases that enteto triggering

he separation cs behavior wand implemen

The SSW cone systems pend acceleratedtrajectories en

onditions whenunder the extrams trigger and

to the systemseparation obsvent in which t

m senses the de

eparation thanditions are sench angle and piparation pitch

Figure 18: Tr

ics

adequate time ward. The intro

W and aided ie it enters: M

, the PTV wouut recovery. Aced cases withand slides off wpplied to the PT

MinPR class, s to entering a p inputs were bespectively. ed the oscillatioxtraction, but udes with satered the MinP

within the wcut command

was due to thntation of the 9nditions were ak acceleratiod outside thentering the Man the system haction parachurelease cut co

ms timing sequserved in post-the conditions fined separatio

n actually expsed to when thitch rate statesrate was 15˚/se

rajectory Clas

for the Prograoduction of thein identifying

Maximum Pitch

uld tend to acceAn example is h flat or translawith small ratesTV at the four

had large dowa different side both typically g

The larger on magnitudes

still producedtisfactory sepaPA side werewindow limitoutside the d

he systems po90 ms avionic s

being met pron and as a e defined wi

axPR window has already begutes on the neommand timinuence eliminate-test reconstrucare sensed and

on conditions, F

erienced. Thihe actual strap cs. A typical raec and the actu

ssifications

ammer e down

three h Rate

elerate shown ational s, as if attach

wndraft of the

greater ramp

of the d heat aration e also ts and defined ositive system rior to

result indow. satisfy gun to egative ng was ed the ctions. d a cut Figure

is was cutters

ate loss ual test

data showeand rates. to 10˚/sec enhancemeperformancnow be corate seen in

The devmainstreamextraction/fidelity of simulationseparation conventioninternal fobeen adopt

Comparidata reconPTV/CPSScontact phevehicle du

pitch ratesassumed thwindow deforces aboinitial phasequence.

Fig

ed we separateProtecting fromto safeguard

ent of the AEce for the extra

orrelated to tesn flight tests at

VI.elopment and

m simulation s/separation anstate vectors res. The assof CPAS test

n that accountsorce interactionted with exceptisons alongsidstruction effor

S extraction-sepenomenon that

uring the free f

s and α<95˚ thhat any non-nemonstrated ca

ove 4100 lbs. ases of flight h

gure 21: PTV

Americ

ed at approximam pitch rate re

from unfavorESM and MCaction and sepast data and simt separation.

Conclusionintegration of sequence has inalysis techniqequired to initisumption of t articles has bs for 90 ms avins, and downtional test resu

de established ts have been pparation event t occur during fall flight phas

hat result in apnegative pitch ases acceleratiThe overall f

has improved.

V Separating H

can Institute of

ately 5˚/sec, Fiaching the 0˚/srable trajector

C capability haaration phase o

mulate the pitc

n the AESM intointroduced statques and impiate primary NA

modeling inbeen replaced ionics system t

ndraft forces. Tults.

NASA simulaperformed to v

has been estabrelease. The mse are better u

pex forward atrate would re

ing outside thefundamental un This allowed

Heat Shield Fo

f Aeronautics a

11

igure 20. The sec threshold hries that enter as resulted inof flight can ch and pitch

o the CPAS te-of-the-art proved the ASA driven

nstantaneous with a new time delays, These have

ations and testerify and validblished with thmoment-forces understood and

ttitudes at progesult in favorabe defined windnderstanding o

d CPAS to ov

orward

and Astronauti

same behaviohas prompted anr from the Man flight-like pr

t date the AESMe insight attain generated by t

d can now be hwindow for attitudes. Inshield and favorable atmoments thforward. The addenhanced ounew trajectoseparation wwindow lim

10˚/sec to protgrammer deplo

able PTV attitudow. These cof the vehicle vercome challe

Figure 20

ics

or was seen fornalysts to raiseaxPR and Mireflight predic

M. A physics-bned of the forcethe extraction pharnessed withoptimal PTV

nterferences beCPSS front

ttitudes by opphat tend to or

dition of the dur thinking anory classes thwindow. As amit was shifttect from PTVoyment. Earliude. Cases cases were attr

dynamics expenges in this h

: Extraction-Heritage

r all measured e the MinPR wnPR window.

ctions. The s

based solutione interactions aparachute and h a smart sepaheat-shield fo

tween the PTVt bumpers suposing aerodyrient the PTV

downdraft forcnd shed light ohat enter the a result, the Mted from 0˚/s

V cases with neier defined winentering the Mributed to dowperienced durinhighly comple

Separation Tee

angles window

The system

to the and re-mated

aration orward V heat-upport

ynamic V apex

ce has on two

smart MinPR sec to egative ndows

MinPA wndraft ng the ex test

est

American Institute of Aeronautics and Astronautics

12

References

1 Machin, Ricardo A. and Evans, Carol T., “Cluster Development Test 2 an Assessment of a Failed Test,” 20th AIAA Aerodynamic Decelerator Systems Technology Conference and Seminar, Seattle, Washington, 4 – 7 May 2009, AIAA paper 2009-2902. 2Cuthbert, P.A. and Desabrais, K.J., “Validation of a Cargo Airdrop Software Simulator,” 17th AIAA Aerodynamic Decelerator Systems Technology Conference, Monterey, California, May 20-22, 2003, AIAA Paper 2003-2133. 3Cuthbert, P.A., “A Software Simulation of Cargo Drop Tests,” 17th AIAA Aerodynamic Decelerator Systems Technology Conference, Monterey, California, May 2003, AIAA Paper 2003-2132. 4King, Ronald, Wolf, Dean, and Hengel, John., “Ares Decelerator System Heavy Air Drop Test Program,” 21st AIAA Aerodynamic Decelerator Systems Technology Conference, Dublin, Ireland, March 2011, AIAA Paper 2011-2504. 5Stuart, Philip,“CPAS Aerodynamic Database Application Programming Interface User’s Guide,” Version 2.0.0b2, CPAS Analysis IPT, NASA-JSC EG Document, December 2011.