Initial Results from In-orbit High Voltage Experiment on HORYU-4

T. Shimizu, H. Fukuda, K. Toyoda, M. Cho and HORYU-4 Project Team

Laboratory of Spacecraft Environment Interaction Engineering Kyushu Institute of Technology

14th Spacecraft Charging Technology Conference, Noordwijk, 7th April 2016

HORYU-4 Satellite (specifications)

T.Shimizu

Size 33x33x33cm, 10kg

Power TJ 34 cells in total, Ni-MH Battery

Telecommand VHF 1.2kbps, L-band DTMF

Telemetry UHF 1.2kbps, S-band 100kbps

Launch H-IIA Rocket, 17th Feb 2016

Orbit 575km, 31deg

Mission 1 Capture ESD Current

Mission 2 Capture ESD Flash Light

Mission 3 High Voltage Technology Demonstration

Mission 4 Secret Ink

Mission 5 Vacuum Arc Thruster

Mission 6 Langmuir Probe

Mission 7 Photoelectron Measurement

Mission 8 Earth Imaging

Mission 9 DigiSinger (Vocaloid)

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AIM

Idea of New Technology

Simulations Ground Testing

In-Orbit Demonstration

Practical Application

So, bring a laboratory into orbit Repeat same tests performed on ground

Vacuum Pressure Plasma Conditions Satellite Motion Chamber Wall

It is still difficult to fully simulate complex space environments…

Verify Ground Testing Method Qualify New (High Risk) Technologies

results comparison Evaluate testing method Find conditions

In House Developed Instruments

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350V 2mA High Voltage Bias Distribution

Sen

sor

Sign

al

Trig

ger

Sign

al

Video Signal

OBC Bus

Experimental Solar Array

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12cm

15

cm

-Z Panel +Z Panel

Overview of Experimental Setup

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Other Electron Collectors

High Voltage Solar Array (Bias Source 350V) +

- Cu

rren

t P

rob

e

To Oscilloscope (ESD Current Waveform)

Connect to Ambient Electrical Potential

Current

Signal

Video Camera To Video Capture Board (Discharge Flash Light Image)

Samp

le Solar A

rray

Plasma

Elec

tro

n C

olle

cto

r (+

Z)

High Voltage System GND

Arc

Cap

acit

or

Elec

tro

n C

olle

cto

r

Connected to High Voltage System GND

Flight Nominal Solar Array on +Z Panel

Shimizu et al., “Solar Array Electrostatic Discharge Current and Image Captured in Orbit”, Journal of Spacecraft and Rocket, 2016. Submitted

Schematic of Experimental Setup

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HVSA

SCM

Electron Collectors

Arc Counter

To BigApple

Return from BigApple

Valuable Capacitor

Trigger Check

V-I measurement circuit

From Left side −Z_Nominal +Z_Nominal −Z_Film +Z_Film +Z_Coating

HVsystem_GND

Inhibit

Generation Voltage Measurement

CH2 CH3

CH1

CH4

High Voltage Solar Array

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+Y Panel

-Y Panel

Current Probes

OB

O A

nal

og

Inp

ut

High Voltage Distribution

On Board Oscilloscope

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Channel CH1 CH2 and CH3 CH4

Input Range -10 to 70 A, -0.1 to 0.7 kA 0 to 40 A 0 to 400V

Vertical Resolution 8bit 8bit 8bit

Sampling Rate 6MHz 40MHz 1MHz

Record Length 170µs 205µs 1024µs

Analog Signal (4CH)

Discharge Currents &

Capacitor Voltage

Trg Out to AVC Shutter

Arc Vision Camera

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Resolution 752x480 (interlace)

Frame Rate 60fps (120fps max)

Record Length 2.8 frames

Gradation Depth 8bit

Storage 24 events

Power 0.5W in total

+Z Panel, Experimental Space

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AO Secret Ink (degradation of Films)

Sample Solar Arrays

Semi Conductive Coating Array

Nominal Array

Film Wrapped Array

Video Camera With Fisheye Lens

Discharge Location

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1st: 24th February 2016 2nd: 9th March 2016

Entered eclipse After 25min

Captured Waveform and Image

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tim

e

Shimizu et al., “Solar Array Electrostatic Discharge Current and Image Captured in Orbit”, Journal of Spacecraft and Rocket, 2016. Submitted

Observed Waveforms

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Temperature during the 1st Experiment

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Time [hour]

Tem

pe

ratu

re [

de

gC]

___ +Z Camera Temperature ___ Hood Temperature ___ OBO Temperature (internal)

Sampling Frequency: 10min

Captured Image

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tim

e

tim

e

Conclusion and Future Works

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HORYU-4 has successfully operated and conducted the high voltage experiment. We acquired the world’s first results from in-orbit experiment. The acquired waveforms were different from our expectations… Our expectation was that low peak currents and long discharge durations. This observation will be clarified through further experiments both in-orbit and on the ground. The obtained data will be used to evaluate and improve present ground testing methods (e.g. ISO-1221).

T.Shimizu

T.Shimizu

Thank you