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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
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