Final report on Engineering model
development of 6U Cube Sat observing
atmospheric and space electricity for theearthquake prediction
Masashi Kamogawa (UNISEC, Japan)
Masahiko Yamazaki (UNISEC, Japan)
Ganapathy Pattukandan Ganapathy(Anna University, India)

WNI WxBunka Foundation, Asia-Pacific region project furtherance【2020年度成果概要】
衛星のブレッドボード・モデルは、ミッション機器、海外調達品を除けば完成段階にあり、早期完成を目指すべく、エンジニアリングモデルの製作に着手した。
雷電波による地震先行電離圏擾乱を検知するのみならず、航行用VLF電波を用いた地震先行電離圏擾乱の検知の可能性を示した。

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Observation of EQ precursor using CubeSat• Ionospheric D-region electron enhancements are the mostplausible precursor because of high spatio-temporal observation.

• This precursor investigation contributes to the EQ prediction study,accompanying the seismic/geodetic and geochemical precursors,
because the satellite observation facilitates their validation.

Case of Real EQs

Case ofRandomly-generated EQs(Nemec et al, GRL, 2008)

Additional DEMETER analysis for mission design.
• In addition to the analysis on lightning-origin EM waves, the VLF
transmitter EM waves is analysis to monitor the D-region
ionospheric electron density enhancement.
• EQ-related electric-field intensity depression was clearly found.

LightningEpicenter

Time-series of VLF electric-field spectrum observedby the DEMETER in the EQ-related orbit.
The time equal to zero indicates the closest to the future epicenter.

Time-series of electric field data
at 19.8 kHz (NWC) on EQ and 7
control orbits.

Current status of engineering model of Prelude• Integration test for engineering model was conducted
except booms, electric probes, VLF receiver and electronemitters.

VLF波帯電場

Electrodeセンサ
VLF波帯電場センサ

Electrode⚫ Validation of initial operation and phase.
⚫ Subsystem control using command⚫ Microcomputer operations for EPS
and CDH⚫ Power supply and block controls⚫ Dyneema wire parts and solar panel
extension.
⚫ HK data acquisition, store, andtransfer.

20㎝

Satellitesubsystem

Simulatedgroundstation（PC）

30㎝

Integration test

Command and Data Handling（C&DH）• Validation of HK data acquisition (SPI communication) andcommand for subsystems was conducted using VA10820
microcomputer (radiation resistance).
• Next step for Engineering model
1. Data store of HK and GPS
data into flash memory.
2. Health monitor function foreach subsystem using WDT.
3. Confirmation
ofUARTcommunication.
4. Writing program in the FRAM
memory.
5. Command format for
1) Providing GPS timestampfor
ADCandmissioncomponents.
2) Providing EQ timeEPS

C&DH

Communication（COM）• From mission analysis, the downlink data amount, thecommunication requirement, communication protocol weredesigned.
• The transmitter and received and antenna were selected.
• Nighttime sensing（DL data amount: 63.5[MByte/day]，Required communication period;𝑡>63.5 [𝐬]）• Nighttime sensing（DL data amount: 88.5[MByte/day]，Required communication period;𝑡>88.5 [𝐬]）• Possible communication period (more than margin 3)• Candidate A station: 158.7 [s]• Candidate B station: 703.9 [s]• Candidate C station: 703.8 [s]• Next step for Engineering model• Development of transmitter/receivercommunication interface board..
Communication protocol
for satellite and ground stations.
6Electric Power Subsystem（EPS）
We confirmed as follows:• Inhibit controller activating the inhibit
switch provided the electric power forsatellite subsystems a certain period
after detecting the satellite release.
• MPU simulating C&DH microcomputer
provided the electric power for each
Battery
subsystem through the command.
• Power consumption for each system and galvanometer
battery voltage was measured.
EPS
A-to-D
conveter

InhibitControl IC

microcomputer• Next step for Engineering model
The following functions will be C&DH
developed.
microcomputer• Charge control and battery protection.
電源供給制御用基板• Power supply stop due to overcurrent.
• Heater
controlfor
batterytemperature.
• Melting Dyneema wire for the boomsystem.

Attitude Determination and Control System（ADC）• In the Bread Board Model (BBM), dummy component wasused for the integration test.
• After CubeADCS developed by South African company wasreceived, we started the test.．
• Numerical simulation of attitude control for the geocentric
direction and geomagnetic environment was conducted.

• Next step for Engineering model• Construction of HILS environment

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The Spacecraft Structure and Thermal Design Considerations• SC structure was designed. Each component was placed.
• Using simulation “Thermal Desktop”, the thermal design wasconfirmed.

• Next step for Engineering model• Construction of HILS environment
to evaluate attitude control system.

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