analysis of space missions with application to … · taller de diseño de picosatélites ......

TallerdeDiseñodePicosatélites(CUBESATS)yEstacionesdeTierra

TallerdeDiseñodePicosatélites(CUBESATS)yEstacionesdeTierra.©GuillermoOrtega 1

AnalysisofSpaceMissionswithapplicationtopico‐satellites

[email protected]

Wed.October14th,200914:00to18:00

Control Division, TEC-ECM

mailto:[email protected]

mailto:[email protected]


TallerdeDiseñodePicosatélites(CUBESATS)yEstacionesdeTierra.©GuillermoOrtega

• Part1:Fundamentals(30min)– Backgroundonspaceproject’sanalysis,roles,andresponsibilities,inputandoutputoftheanalysisphases

• Part2:Analyzing(1.5h)– Practicalstepbysteptechniques,howto’s,examples,etc.

2



Part 1: Fundamentals (30 min)

• Definitionsandbackground• Roleofspaceanalystinaspaceproject• Spaceprojectphasesandspaceanalysis• Analysistechniques• Analysistools

3



Definitions and background

• Analysisofamission:processofstudyingandanalyzingmissionrelationsbetweenorbit,attitude,andbudgets(link,mass,power,thermal)tofulfilltherequirementsofagivenmission

• Missionanalyst:thepersoninchargeofperformingtheanalysis

• Satellitecategories:– Pico<2Kg– Nano<10Kg– Micro<100Kg– Mini<500Kg– Small<500Kg– Large>1500Kg

4



Role of space analyst in a space project

• Identifyrelevantrequirements,needs,andconstraints

• Trade‐offalternativemissionscenariostofulfillrequirements

• Analyzesystembudgets• Defineamissionconcept• Sketchamissiontime‐line• Shareresultsandproducereport

5



Space analyst skills

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Ascent Entry

Interplanetary

Rendezvous

Loitering

Mission Arcs

Disciplines

Technologies

Propulsion

Aerodynamics

Structures

Systems Optimization

MathematicalmodelingSoftware design and

development

Informatics skills



Space project phases and space analysis

7

Production-ground qualification testing

Detailed definition

Utilization

Disposal

ECSS-E-10 http://www.ecss.nl

B C E FD0 A

Mission needs identification

Feasibility

Preliminary definition

http://www.ecss.nl

http://www.ecss.nl



Space project phases and space analysis

8

0 A

Mission concept definition

Mission feasibility analysis



Phase 0 work flow

9

KoMStudy of

mission requirementsmission needs

mission constraints

Identification of mission concepts

Mission Definition Review (MDR)

Analysis of programmatics



Analysis techniques

• Timemeasurement:aJuliandateisdefinedastheintervaloftimeindaysandfractionsofaday,sinceJanuary1,4713BCGreenwichnoon,Julianprolepticcalendar

• Spacemeasurement:coordinatesystemsandtheircorrespondingtransformations

• AstrodynamicsIntegratorsandPropagators:Anintegratorisanalgorithmtoperformthemathematicaloperationknownasintegration,afundamentaloperationincalculus.Apropagatorisamathematicalalgorithmabletocomputeapredictedstateofaspacecraftbasedonitspresentstate

10

http://en.wikipedia.org/wiki/Integral

http://en.wikipedia.org/wiki/Integral

http://en.wikipedia.org/wiki/Calculus

http://en.wikipedia.org/wiki/Calculus



Analysis techniques: Orbital Elements

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νω

Ω

i

Ascending node

Vernal Equinox

ApoaxisOrbital plane

Equatorial plane



Analysis tools

• Simplespreadsheet–SMADSbook

• Mediumcomplexitytools–STK,SIMvis,STA

• Highaccuratetools–GNCDE,SpaceLIB,ATPE

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Analysis tools: Spreadsheet

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Analysis tools: ASTOS

• Usedforascent,re‐entryapplications

• DevelopedbyASTOSSolutionsGmbH

• Version6.1AvailableinWinXP,Linux(sooninMAC)

• http://www.astos.de

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http://www.astos.de

http://www.astos.de

http://www.astos.de

http://www.astos.de



Analysis tools: LAREDO

• CalculatetrajectoriesofrendezvousanddockingbetweentwospacecraftinanyplanetoftheSolarSystem

• Thetoolisabletoperformthecalculationoftrajectoriesbyusingasetofpredefinedmaneuversspecificallydesigntoperformtherendezvousanddockingbetweentwospacecraft

• Developedby“GMV”

• Version1.7.1inWinXPandMATLABR14

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Analysis tools: POINT

• POINTisintendedtosupporttheanalysisanddesignoflowthrusttrajectories

• ItcanbeusedinfeasibilitystudiesforthefastassessmentoftypicalquantitiescomingfrommissionanalysisliketotalVrequirements,timeofflight,departureandarrivalconditions

16



Analysis tools: STK

• CommercializedbyAGIinUS

• Calculatepositionandorientation

• Evaluateinter‐visibilitytimes

• Determinequalityofdynamicspatialrelationships

• OnlyWindows

• http://www.agi.com

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http://www.agi.com

http://www.agi.com

http://www.agi.com

http://www.agi.com



Analysis tools: STA

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http://sta.estec.esa.int





Part 2: Analyzing (1.5 h)

• Studyingtherequirements• Performingtheanalysis

– Problemphasing– Launchandorbitinjection– Deploymentandcommissioning– Stationkeepingandorbitmaintenance– De‐commissioningandgraveyarding

• Reportingandsharing

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Analysis steps of phase 0

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Studying the requirements

Performing the analysis

Reporting and sharing

KoM

MDR

Time-Line



Study case

• StudyofthelowEarththermosphere

• Thethermosphereisbiggestofallthelayersoftheearth'satmospheredirectlyabovethemesosphereanddirectlybelowtheexosphere

• Withinthislayer,ultravioletradiationcausesionization

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Troposphere

Stratosphere

Mesosphere

Thermosphere

Exosphere

500

90




22




KoM

MDR

Mission Statement + Requirements

Time-Line



Mission statement

• TostudyinsituthetemporalandspatialvariationsofanumberofkeyparametersinthelowerEarththermosphereataltitudesbetween90‐300km:– Density– Temperature– Pressure– Particleconcentration– Radiation– Dragmodeling– etc

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Mission Statement

must be cle

ar, and

brief



Needs and Constraints

• ThesetofmeasurementshallprovideacomprehensivedatabaseastoallowtoupdatetheEarththermospheremathematicalmodels

• Thesetofmeasurementshallbeobtainedinlessthanhalfayear(<6Months)fromthebeginningofthemission

• Thetotalcostofthemissionshallbelessthan5MEUR,includingoperationsbutexcludinglaunchcostthatshallbetreated

24



Requirements

• Themeasurementshavetotakeplaceeveryday(dayandnightvariations)

• ThemeasurementshavetotakeplaceinalllongitudesoftheEarth

• ThemeasurementshavetotakeplaceinlatitudesoftheEarthbetweenZerodegand80deg

• ThemissionshallcomplywithESAECSSStandardsantheESAcodeofconduct

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26




KoM

MDR

Mission analyst studies all details of

the requirements and proposes alternative scenarios to trade-off

Time-Line



Studying requirements, needs, and constraints

• Payloadshallbeformedbyasetofinstruments:densitometer,thermometer,radiometer,etc

• WeneedalmosttotalEarthcoverage• Weneedabrieflastingspacecraft(only6months)• Orbitshallbebetween300and90Km=>Allows

decay• Continuosmeasurementanddownloadtoground

station• Levelofautonomyisrelativelylow• Costisamaindriver!(5MEUR)

27



Studying requirements, needs, and constraints

• Orbitshouldnotrepeatgroundtrack• Orbitshouldswapallaltitudesbetween300and90

• Allmeasurementsshallbespatiallycorrelated

• Downloadtogroundshouldtakeplaceassoonasmuchaspossible(noon‐boardstoragecapabilities)

28



First mission scenario

• 1singlespacecrafttypeMINI(about500Kg)• Possibleorbittypestostudy:

– Polarorbit– Inclinedorbit– SunSynchronousorbit

• Impossibleorbittypes(discarded):– GEOstationary– Molnya– etc

29



MiniSAT possible concept

• MiniSATfeatures– Mass:500Kg– Side:50cm– Area:0.25m2

– Cd:1.05

• Control– activewithIMUand

RWA

• Propulsion:– 6redundantthrusters

• Power:– Smallsolararrays

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First mission scenario: Polar

• PolarorbitsaregoodforentireEarthcoverage

• At300Km,thisorbitswapstheentireEarthafterabitmorethanaday

• Earthrevolvesunderneath

31



First mission scenario: Polar

• Semimajor‐axis:• Eccentricity:• Inclination:• RAAN:• Arg.ofperiapsis:• Trueanomaly:• Apogeeradius:• Perigeeradius:• Period:• Meanmotion:

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First mission scenario: Inclined

• Inclinedorbitsonlysatisfytherequirementofcoverageoflatitudesbetween80degandzerodegwhentheyhave80deginclinationormore

33



First mission scenario: Inclined


34



First mission scenario: Sun-Synchronous

• WillaSun‐Synchronousorbitwork?

35




• ASun‐Synchronousorbitcombinesaltitudeandinclination

• anobjectonthatorbitascendsordescendsoveranygivenpointoftheEarth'ssurfaceatthesamelocalmeansolartime

36




• SSOorbitsaregoodforEarthobservationmissionssincethesatellitecrossestheEquatoralwaysatthesamelocaltime

• Theysimplifythesatellitedesignsinceeclipsedurationsarealmostconstant

37





38



Checking mission life time possibilities

• Missionshalllastlessthan6months:studydecayandmeanstoprolongmission

39



Alternative mission scenario: PicoSAT

• Severalsatellites(flotilla)typePICO(2Kg)

• Possibleorbittypes:– Polarorbitconstellation– Walkerconstellation

40

Student with CubeSAT at the PicoSatellite workshop at ESTEC, Netherlands, January 2009



PicoSAT possible concept

• PicoSATfeatures:– Mass:2Kg– Side:10Cm– Area:0.010m2

– Cd:1.05

• Control:– Magneticfield

• Propulsion– None

41



Alternative mission scenario: Polar constellation

• PolarconstellationsallowcoverageofentireEarth

• Caseof5satellitesat300Km

• Temporalandspatialseparation

• Orbitsencounteratthepoles

42





43




44



Avoiding collisions on Polar constellations

• Collisioncanoccurwhensatelliteencountereachotheratthepoles– RAANseparatesthemtemporarily– ArgumentofPeriapsisseparatesthemspatially

45



Alternative mission scenario: Walker constellation

• Isawellknowpatterndesignforconstellations• Use3numberstodefineaconstellation:T/P/F

– Tisthenumberofsatellites– Pisthenumberoforbitalplanes– Fistherelativespacingbetweensatellites

• S=T/Pnumberofsatellitesperplane• PUisthePatternUnitanis360deg/T• PlanesarespacedatintervalsofSPUsinnode

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• PossiblegoodsolutionwithWalker=N/5/30

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48





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Trade-off between the two scenarios

50

Singlesatellite FlotillaDeployment X

Operations X

Coverage X

Resolution X

Failuretolerance X

Cost X

FINALSELECTION X



Orbital perturbations

51

• Earthoblateness:

• SunandMoon:

• Earthatmosphericdrag:

• Solarradiationpressure:




52




KoM

MDR

Detailed analysis of the performance of a single PicoSAT in our Walker constellation

Time-Line



Problem phasing

• PicoSATlaunchandorbitinjection• PicoSATdeploymentandcommissioning

• PicoSATstationkeepingandorbitmaintenance• PicoSATde‐commissioningandgraveyarding

53

Time-Line

Launch and orbit injection

Station Keeping

De-commissioning

Graveyarding

Deployment



Launch and orbit injection

• Analysisofascenttrajectorywithorbitalparameters:– Altitude:300Km– Inclination:78deg

• Erroratlauncher’sinjection:1Kmallaxis3‐sigma• Launchvehicle:VEGA

54

ELA launch pad

300 x 300

VEGA launch

PicoSAT: 2Kg



Deployment

55

P80 flight

Z23 flight

Z9 flight

AVUM1st ign.



VEGA AVUM release strategy

56

2nd satellite: 2 Kg

3rd satellite: 2 Kg

4th satellite: 2 Kg

5th satellite: 2 Kg

30 deg RAAN



Deployment and commissioning

• Deploymentmustbedoneongroundstationcoverageandvisibility– Findoutwhich

groundstationcanhavecontactwithPicoSATafterthelauncher’srelease

57




• 10minutestransmissionandantennadeploymentdeadtime

• Switch‐onandantennadeployment.• Initialsatelliteacquisition• Validationofthecorrectoperationenvironmenton‐boardthesatellite

• Validationofthespace‐grounddatalink(RFTransceiver)

58




59

Cebreros Kiruna

Trad

e-off

be

twee

n Kiru

na an

d

Cebre

ros



Station keeping and orbit maintenance

• Analysisofbudgets:– Massbudget

• PicoSATwillhavenopropulsion.Hence,themassbudgetwillbeconstant

– Linkbudget• EstablishlinktocommandPicoSATanddownloaditsdata

– Powerbudget• HowPicoSATwillhaveitspower

– Thermalbudget• Howitwarmandcooldown

60



Link budget

• Frequency:2.2GHz• PicoSAT

– Power:0.15W– Downlink:1.2Kbps– Pointingerror:25deg

• Groundstation– Power:0.70W– Uplink:0.3Kbps– Pointingerror:0.1deg

• Contactsperday:1

61



Coverage

62



Coverage: GENSO

• Aworldwidenetworkofgroundstationsandspacecraftwhichcaninteractviaasoftwarestandard

• http://www.genso.org

63

http://www.genso.org

http://www.genso.org



Coverage: ESAC ground station

• EducationalgroundstationsatESAC• http://www.esa.int/esaMI/ESAC/index.html

64



Power and thermal analysis

• Thermal:passivethermalstabilization

• Power:solararraysmountedinallpossiblecubefaces

65

Solar array



De-commissioning and graveyarding

• ESAcodeofconduct:ESA/ADMIN/IPOL(2008)2Annex1

• http://www.esa.int/esaMI/Space_Debris/SEMQHL05VQF_0.html

• Endoflifeoptions:

66

http://www.esa.int/esaMI/Space_Debris/SEMQHL05VQF_0.html








De-commissioning and graveyarding

67

• PicoSATdragsintotheEarththermosphere• In84daysitwillre‐enterandburn




68




KoM

MDR

Write a document for the MDR Review

Time-Line




• TableofcontentsforMDRreview:–Problemphasing– Launchandorbitinjection–Deploymentandcommissioning– Stationkeepingandorbitmaintenance–De‐commissioningandgraveyarding

69



Backup material

• QB50project:http://www.vki.ac.be/QB50/index.php

• QB50,ANINTERNATIONALNETWORKOF50CUBESATSFORMULTI‐POINT,IN‐SITUMEASUREMENTSINTHELOWERTHERMOSPHEREANDRE‐ENTRYRESEARCH

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http://www.vki.ac.be/QB50/index.php




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