ARCADEEXPERIMENTONBOARDBEXUS13

AND17:DESIGN,INTEGRATIONANDFLIGHT

OFATECHNOLOGYTESTPLATFORMWITHIN

ASTUDENTBALLOONPROGRAMME

MarcoBARBETTA,FrancescoBRANZ,AndreaCARRON,

LorenzoOLIVIERI,FrancescoSANSONE,LiviaSAVIOLI,

FabioSPINELLO,AlessandroFRANCESCONI

1st SymposiumonSpace

EducationalActivities

Padova,9-11December2015

CISASG.Colombo, University ofPADOVA,

ViaVenezia15,35131Padova(ITALY)

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CONTENTS

Ø EXPERIMENTOBJECTIVES

Ø EXPERIMENTOVERVIEW(2013)

• DockingSubsystem

• MotionControlSubsystem

• ProximityNavigationSubsystem

Ø ARCADEEVOLUTION

Ø FLIGHTRESULTS

Ø LESSONSLEARNED

Ø CONCLUSIONS

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EXPERIMENTOBJECTIVES

PrimaryObjectives:

• Totestinnovativesolutionsforproximitynavigation,attitudecontroland

docking suitedforminiatureautonomousspaceandaerialvehicles

• Toevaluatedisturbancesaffectingoperationsatdifferentaltitudesonboarda

stratosphericballoonofferedbytheREXUS/BEXUSprogramme

• Torelateperformancestodisturbances

SecondaryObjectives:

• Tocollectenvironmentaldata(pressure/temperatureprofiles)

• Todeterminewinddirectionandspeed

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EXPERIMENTOVERVIEW(2013)

MainElements:

• SMAV (SMAll AirVehicle)

• PROXBOX(PROXimity BOX)

• STRUT(STRUcTure)

• DockingSubsystem

• NavigationSubsystem

• WindSensors

• Webcam

SMAV

PROXBOX

STRUT

Balloon

frame

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DOCKINGSUBSYSTEM

• BasedonSoyuzandATVprobe-drogue configuration

• Probelengthof10cm(SMAV size:20x20x20cm)

• Upto10° ofallowablemisalignment

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MOTIONCONTROLSUBSYSTEM

MainGoal&Architecture:

• ActivelycontrolSMAVyawmovements

• Mainactuator:customreactionwheel

• Backupsolution:DCmotorb/wSMAVandSTRUT

State-SpaceControl

• Statefeedback+integralcontroller

• Disturbancesrejectedoutsidefeedbackloop

• Linearmovementsnotinfluencing attitude

• Backupsolution:manual-tunedPIDcontrollerSMAVReaction Wheel

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PROXIMITYNAVIGATIONSUBSYSTEM

Sensorselection:

• Compactness(minorpartofSMAVvolume)

• Simplicity (hardwarecomponents&softwarecomputationalburden)

Sensorlayout:

• IRLEDemitter(pulsed at10kHz)onthePROXBOX

• TwoIRreceiversontheSMAV

• Reconstructionofrelativerangeρ andyawangleψ

customrelativenavigationIRsensorbasedon

radiationintensitymeasurement

SMAV

IRRECEIVERS

IRLED

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ARCADEEVOLUTION2010- 2013

1)SelectionWorkshop 2)PDR 3)CDR

DESIGNPHASE

(10/2010– 6/2011)

1)Conceptdefinition

2)Baselineconfigurationselection

3)Detaileddesign

4)IPR&EAR

5)BEXUS13flight- 2011

INTEGRATION&TESTPHASE

(6/2011– 9/2011)

4)Integrationandacceptance

5)LaunchCampaign

(October2011)

6)BEXUS17flight- 2013

RE-FLIGHT

(11/2012– 10/2013)

• Substitution of

damagedorobsolete

h/w

• Completere-writingof

software

• Otherdesignupgrades

• Massreduction

Unsuccessfulflight because

ofcriticalsoftwarefailure Successful flight!!!

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FLIGHTRESULTS(1/2)

Dockingsystem

• SuccessfulreleaseoftheSMAV

• Thermaldeformation: in-flight

modificationofactuatorsstroke

• Twocompletedockingandrelease

procedures

Motioncontrolsystem

• Backupmotor successfullypointingandmoving theSMAV

• ReactionwheelsuccessfullytestedwithbothPIDandState-Spacecontrols

PIDControllerManoeuvreState-SpaceControllerManoeuvre

1 2 3 4

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FLIGHTRESULTS(2/2)

Proximitynavigationsystem

• Automaticcalibrationofphotodiodes

electronics(temperature-dependant)

• Real-timeestimationwithon-boardsoftware:

accuracyof17mm– 2.7deg

• Postprocessing:accuracyof5mm– 1.5deg

Thermalcontrolsystemandwindsensors

• Experimenttemperaturealwayswithinoperationalrange

• Estimationofwindtorqueson thevehicle

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LESSONSLEARNED(1/3)ExperimentDesign

• Don’t fallinlovewithdesign ideasbut

asktoexpertsforwhatalreadyexists

• Thesimpler thebetter:asimple

solution, although lesselegant,is

preferable

• AlwaysoptinfavourofCOTSagainstself-

builtcomponents

• Don’tunderestimatetimetoallocateto

softwaredeveloping. Eveninintegration

isincomplete

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LESSONSLEARNED(2/3)LaunchCampaign

• Finalizeasearlyaspossible theintegration.

Worstproblemshappenat99%ofprogress.

Dropthings ifneeded

• Don’tchangesoftwareatlastevenifit’ssoooo

easy

• Havesparepartsboth forCOTSandself-built

components

• Makesystemsserviceable

• Don’t relyontelecommand forthesuccessof

theexperiment

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LESSONSLEARNED(3/3)

ProcurementandShipping

• Freezelong leadtimecomponentsasearlyaspossible

• Usecomponents frombigdistributors

• ConsiderLi-SOCl2batteryshipping.Couriersarescaredofhazmat!

Testing

• Testflightconfiguration inthemostrealisticway

• Givetestsapriority.Testfirstthingswhichare

likelytohaveproblems inyourmind

OutreachandFunding

• Goodoutreachmeansfunding

• Goodoutreachdevotesafull-timeperson– orevenmore.

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CONCLUSIONS

• Importantscientific andtechnologic results

• Testedcriticaltechnologies for:

• Docking

• Relativenavigation

• Attitudecontrol

• Know-howoftheteamseriously improved

• Bigexperienceaboutspaceprogramsanddeadline-driven teamwork

HOWMANYERRORSBEAVOIDED

THANKSTOTHISEXPERIENCE?

THANKYOUFORATTENTION!

1st SymposiumonSpace

EducationalActivities

Padova,9-11December2015

CISASG.Colombo, University ofPADOVA,

ViaVenezia15,35131Padova(ITALY)