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11th Spacecraft Charging Technology Conference

New Mexico USA

Temperature Dependence on Electrostatic

Environment

T, Okumura. J, Harada. Y, Hagiwara. K, Nitta. M, Takahashi

Japan Aerospace Exploration AgencyT, Toshimitsu. K, Toyoda

K ushu Institute of Technolo

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BackgroundNo2

Time

ial

Vcgee

e e

P

oten

e e ee

Vsat

Discharge number estimation

Proper experiment condition for ESD test

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Collaboration researchNo3

JAXA KIT

JAXA KIT

voltage

Discharge LEO

voltage

Discharge LEO

frequency

frequency

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No4

Experiment technique and result

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Experiment system (JAXA)No5

Electron beam gunSurface potential meter

IR camera

PC

PCPC

Discharge positionTemperature

monitor

Vb

Cext V

Analog signalOSCShroud

Oscilloscope

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Solar array couponNo6

35mm

5mm MJ cell

CG =100m

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Experiment system (JAXA)No7

Shroud

XY stageTREK

ea pane

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Experiment conditionNo8

-5

Current density: 4mA/m2

Acce erat on vo tage: 9 V

Bias voltage: 6kV

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Discharge circuitNo9

C5C3C2C1C4

Vb

V Vp

CB

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Test sequenceNo10

Surface potential distribution

Beam irradiation

Discharge?

YesYes

No

x sec

Surface potential distribution

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Discharge position and current waveformNo11

20C -110C

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Discharge position and surface potentialNo12

20C -110C

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Surface potential profileNo13

Threshold voltage

Charging speed

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Threshold volatageNo14

Room Low

temperature temperatureThreshold 1.3kV 1.4kV

voltage

Standard 0.5 0.1deviation

Threshold voltage does not depend

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No15

Experiment technique and result

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Experiment system (KIT)No16

ECR plasma sourceQMASS

IR camera

PC

Discharge positionShroud

Vb

Cext V

Analog signal OSCSheet heater

Oscilloscope

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Experiment system (KIT)No17

Solar array coupon

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Solar array couponNo18

35mm

75mm

MJ cell=

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Test sequenceNo19

Expose to air for 3hours

Experiment: Room temperature for 60min

Increase the temperature by seat heater Increase bias voltage

Experiment: High temperature for 60min

Decease the temperature by LN2

Experiment: Low temperature for 60min

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Experiment conditionNo20

Vbias[V]

Experimenttime[min] Ne[1/m3] Te[eV] Pressure[Pa]

temperature[]Hig

hroom low

-200 60 61012 0.7 2.910-264

~

66

30

~

31

-34

~

-29

-300 60 71012 0.7 2.710-264

~

65

30

~

30

-42

~

-34

-400 60 71012 0.7 3.610-263~

65

20~

39

-46~

-33

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Temperature dependence on discharge numberNo21

Bias Room(30) High(60) Low(-30)

-200 0 1 6

-300 3 9 28-400 15 11 60

Discharge frequencyLow temperature Room tem erature

Same result as JAXA

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SummaryNo22

Threshold differential volta e does not de end on tem erature

in GEO environment Arc frequency increases with decreasing temperature in JAXA

an

We need to concern the temperature to estimate the charging speed of

insulation material

Proper exper ment con t on or ESD test In terms of GEO environment test to investigate the threshold voltage,

we do not need to care about the temperature

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Future workNo23

Absorbed material effect on discharge

requency

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