sei spring 2009 space based solar power presentation

8/19/2019 SEI Spring 2009 Space Based Solar Power Presentation

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Space Based Solar PowerSatellite Conceptual Design

for Retrodirective Control

Space Engineering Institute

Spring 2009


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Overview

• Creating a satellite odule t!at will "eattac!ed to a #apanese e$periental satellite

in a %ow&eart! or"it'

• Our tea o"(ective is to create a satellite

odule t!at can test t!e retrodirective "ea

control et!od of sending icrowave power

"ac) to Eart!'

• *!e odule ust provide its own power+ and!ave its own t!eral anageent s,stes'


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-odule S,steSandwic! Design

EnergyStorage &PowerConversion

SpaceEnvironment & Orbit

AntennaArray

Structures&Materials

RetrodirectiveControl logic

Photovoltaic Cells

ThermalManagement


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Environent .nal,sis


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Seester /oals and E$pectations

• Becoe failiar wit! Satellite *ool it software• -odel a cu"ic satellite and evaluate solar energ,

collected at eac! of its si$ faces to identif, t!e

optiu location for t!e solar panels

• Deterine t!e a$iu+ iniu+ and averagesolar energ, collected on t!e optiu location during

one or"it


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Satellite Orientation•Orange-North•Green- South•White- Nadir• Yellow-Zenith•Purple-Leading

•Teal- Trailing


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Satellite Or"it Options

•/eostationar,• .ltitude1 3+456 )

• Inclination1 07

• %ow Eart! Or"its

8 Criticall, Inclined Sun S,nc!ronous1

• Perigee altitude1 00 )• Retrograde inclination1 ::6'3637

8 Circular :

• Altitude: 500 km

• Inclination: 45º

8 E*S&;II1 #apanese satellite wit! siilar initial conditions• .ltitude1 330 )

• Inclination 37


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Energ, and Power Received

• Power α cos

8 =? angle "etween t!e sun vector

and t!e vector pointing noral to

t!e face

8 @nits1 A2• Energ,?Power*ie

8 @nits1 A#2

8 .lso dependent on t!e cosine of =

http://solar.mridkash.com/wp-content/uploads/cosine-law.jpg


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.pproac!

• S* provides angular data for eac! face of t!e cu"icsatellite

• .ngular data are converted to power AF2

• Power data are converted to energ, data A#F2


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Data fro S*


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Data fro S* The enith! "adir! #eading and Trailing

$aces have appro%imately the samee%posure to the sun The antenna will belocated on the "adir $ace! so itreasonably $ollows that the solar panelsbe placed on the enith $ace! directlyopposite the antenna

A circular orbit with an altitude o$ '(()m and inclination o$ *'+ was chosen!because with the options available! thisorbit allows the solar panels to receivethe most sunlight

.verage Solar Glu$1 One Hear 53'43 2

.verage Solar Glu$1 In Sunlig!t 5'5 2

-iniu Solar Glu$1 0 2

-a$iu Solar Glu$1 :66 2


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*!eral -anageent


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*!eral -anageent

O"(ective• *o perfor t!eral anal,sis of t!e satellite and

ensure a suita"le operating environent for t!e

pa,load'

• *ools 8 *!eral Des)top software

Researc! *opics

• %ow eart! or"it environent

• *eperature reuireents for internal coponents

• Cooling!eating et!ods


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E$ternal Environent

In %EO+ t!e satellite will "e !eated ",1• Direct sunlig!t

• Eart!Js al"edo

• Eart!Js IR eittance

*!e total !eat a"sor"ed ", t!e satellite will not reain

constant' Gluctuations occur due to1

• Enteringe$iting Eart!Js s!adow

• ;ar,ing surface conditions on Eart!


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Satellite Interior *!e interior environent of t!e satellite ust "e )ept at

a proper teperature range' -ost electronic euipent

on"oard ust operate in a surrounding teperaturerange of 0 to 30 degrees Celsius'

Gactors to consider for t!e internal energ, "alance1

• Gluctuating e$ternal !eat rates

• Keat released ", electronic euipent

%ow level

"aselineoperation

Kig! level

during

periodic

transissi

on

• *!erop!,sical properties of structural aterial


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CoolingKeating -et!ods

E$ternal• Radiators1 Do not reuire energ,' Release !eat wit!out re&entr,

Internal

• Thermoelectric Coolers/Heaters1 Reuire energ,' Cana"sor"eit !eat ", reversing polarit,

• Mechanical cooling1 E$pander+ copressor+ or !eat

e$c!anger' *a)es up space and weig!t'

• Resistive Heating1 Reuires energ, "ut eleents are copact

in siLe'

• Heat i!es: Passive


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*!eral Des)top

O"(ectives• Develop a odel for t!e satellite odule'

• @se t!e or"ital inforation fro S* to deterine t!eral

environent of t!e satellite'

Progress

• In process of creating odels'


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-aterials and Structures


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Structural Reuireents

*!e satellite ust !ave a"ilit, to1• it!stand launc! loads

• Provide desired rigidit,

• Protect sensitive pa,load coponents froe$tree teperatures'


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-aterial Selection

Ti"Al4# Titanium allo$ #%&

Aluminum Allo$' (0(5)

T"5*+

.lt!oug! *itaniu is 60M!eavier t!an .luinu+ it is

over twice as strong'

Possi"ilit, of !aving titaniu

"ased !one, co" e$teriorN (oined ", a saller portion

of aluinu interior'

Currentl, evaluating two different aterials1

Materials

ro!ertiesTitanium'Ti"Al4#+

AluminumAllo$' (0(5)

T"5*+,nits

-ensit$ 4&4. &* g/cm.

Tensile%trength

0 5( Ma

ThermalConductivit$

"&( *.0 1/m&2

Modulus o3lasticit$

**4 (*&( a

Thermal6!ansion

&" . 7*0)"/ºC


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eig!t Coparison

NaturalFrequency(hert!

Thic"ne

## o$Titaniu%

(Ti&'l)!

panel(c%!

Thic"ne#

# o$'lu%inu%

'lloy( *+*,-T&,!

panel(c%!

Weight(per unitarea! Ti("g.%/#

01!

Weight(perunit

area! 'l("g.%/#

01!

++ 23 2,14 &3255 121+

1++ 1241& 32+,& 11*25* 412+

3++ 2134 2,4 425& 1&32&

++ ,2&, &21 1,,25, &424


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Kone,co" %a,er

Planned use of

Kone,co" design1

•Ke$agonal Structure

• @ses t!e least aount of

aterial to create a lattice

of cells wit!in a given

volue

• -aintains strengt!


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Preliinar, Sandwic! Structure

%a,ered design t!at ta)es

advantage of eac! aterialsdifferent t!eral properties'


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Energ, S,ste


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/oal Q Reuireents• Collect Solar Energ, and store it to power t!e RG aplifiers

8 Collect power fro :2 solar panel'

8 Store energ, in a ediu t!at can wit!stand !ig! drain current'

8 Energ, storage edius ust !ave a wide operating teperature

range'


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DC to RG Converter Options

*u"e agnetron 3'5 /KL• Can output 630 wit! 63M efficienc,• Keavier t!an solid state options

8

• Produces ore !eat t!an solid state converters• Reuires a !ig! voltage power suppl,

to e$cite t!e electrons'

/a KE-* solid state converters 3'5 /KL• Gu(itsu converter can output 20 t!eoreticall,• Cree converter can output 3+ coerciall,

availa"le now'• %ig!tweig!t


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Energ, Storage 8 %i&ion

• Gor storing energ, fro t!e p!otovoltaic cells %i&ion and %i&S "atteries are "eing considered'

8 %i&ion "atteries !ave an energ, densit, of ::0 !)g'

8 Saft -PS space series "atteries t!at are alread,

t!erall, insulated and autonoousl, !eated' 8 Kave a wide operating teperature range < &3o G to

:0o G for c!arging and &0o G to :0o G in operation>

8 Built in over current and c!arging circuits into t!e

odule'

8 :4 .! capacit, per "atter, 25;'


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Energ, Storage & Continued

• %it!iu sulp!ur "atteries are "eing consideredfor t!eir !ig!er energ, densit, 8 E$periental+ e$pensive tec!nolog,' 8 o !istor, of satellite use'

• @ltracapacitors 8 Kig! energ, densit, capacitor used for powering t!e

Solid state icrowave converters w!en transitting asignal'

8 @ltracapacitors can !andle 20. continuous current'

8 ill "e used in con(unction wit! t!e %i&ion "atteries topower t!e /a KE-* aplifiers at t!eir a$iucapacit,


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Current Concept

• -a$iu Power Point *rac)er onitors t!e voltage and current

of t!e Solar Panel and trac)s t!e pea) point on t!e power curve'

• Batter, -anageent S,ste trac)s t!e c!arge rate+ voltage

and current'


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.ntenna and Retrodirective

Control


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Retrodirective Bea Control

• *!e ipleentation of retrodirective "eacontrol is critical to accurate "ea pointing+ as

well as t!e overall safet, of t!e s,ste'

• *!e )e, o"(ective is to !ave t!e power "ea

of t!e solar power satelliteJs transitterpointed onl$ in t!e direction of a received pilot

"ea+ w!ic! provides a p!ase reference

• Retrodirective "ea control ensures t!at

icrowave power transission is "ot! safe

and insuscepti"le to accidental isalignent'


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• *!e 2'9 /KL incoing pilot signal isreceived at a Greuenc, of T: andP!ase U:

• *o con(ugate+ t!e received signal isne$t i$ed wit! a reference sourceof Greuenc, 2T: and P!ase Uref

• *!e con(ugated signal is t!en i$editself to produce a signal wit!Greuenc, 2T: and P!ase &2U:

• .fter con(ugated and dou"led+ t!esignal is transitted fro a differenttransitting su"arra,

• *!e coplete p!ased arra,transits a 3'5/KL "ea in t!edirection of t!e incoing pilot signal

Proposed Retrodirectivit,

-et!od


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• %inear -icrostrip Patc!P!ased .rra, .ntenna

• *!e -icrostrip Patc! .ntennawill operate at a Greuenc, of3'5 /KL+ and will !ave anInput Ipedance of 30V

• *!e .ntennaJs designfeatures a $ P!ased .rra,consisting of :3 *ransittingEleents and : nestedReceiving Eleent eac!spaced 0'3W apart

• *!e su"arra,s aree$pected to "e at differentp!ases prior to powertransission

Proposed P!ased .rra, .ntenna

Concept

', -./ *%* #inear Microstrip PatchPhased Array with nested 01 -./

Receiving Element


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.ntenna and *ransitter

Interface• -agnetron

2 RG power is split to feed fed to eac! antenna

su"arra,2 egligi"le power loss

a, occur during

energ, feed

2 %oss e$pected frop!ase s!ifter

• Solid&State

2 Gacilitates electronic"ea steering

2 Power aplifier andp!ase s!ifter are placed

"e!ind eac! transitting

eleent

2 -icrowave filters arereuired to countervail

aplifier&spawned noise


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.dvantages of Proposals-icrostrip Patc! .ntenna

• .dvantages

2 %ow cost to anufacture

2 %ig!t weig!t and low profile

2 Supports "ot! %inear and CircularPolariLation

Retrodirectivit, -et!od• .dvantages

2 Con(ugates pilot signaldirectl, at RG

2 Reduction in t!e nu"er ofelectronics per antenna

su"arra,

2 %ess power consuption

sei spring 2009 space based solar power presentation

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