Faculty Profiles - TOYODA kazuhiro

Papers - TOYODA kazuhiro

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Multicomponent Plasma Expansion Model for Arc Discharges on Large-Area Solar Arrays Reviewed International journal

Katz I., Hoang B., Toyoda K.

Journal of Spacecraft and Rockets 59 ( 1 ) 324 - 332 2022.09

Experimental investigation of total electron emission yield of polyimide film under various temperatures Reviewed International journal

Wu J., Li S., Zhang B., Cao W., Li Y., Toyoda K.

AIP Advances 12 ( 7 ) 2022.07

Difference in threshold voltage of arc inception between electron beam and ultraviolet environment: surface potential measurement with Pockels effect Reviewed

Toyoda K., Kose S., Cho M.

AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022 2022.01

Difference in discharge threshold voltage between electron beam and ultraviolet environment Reviewed

Toyoda K., Sasaki T., Cho M., Ohkubo M., Seki K.

Journal of Spacecraft and Rockets 58 ( 3 ) 619 - 627 2021.01

Development of a Direct Drive Vacuum Arc Thruster Passively Ignited for Nano-satellite Reviewed

CHO MENGU

IEEE Transactions on Plasma Science 44 100 - 106 2016.01

On-Orbit Experimental Result of a Non-Deployable 430-MHz-Band Antenna Using a 1U CubeSat Structure Reviewed International journal

Nakayama D., Yamauchi T., Masui H., Kim S., Toyoda K., Malmadayalage T.L.D., Cho M.

Electronics (Switzerland) 11 ( 7 ) 2022.04

Experimental investigation on particle size and launch angle distribution of lofted dust particles by electrostatic forces Reviewed

Orger N.C., Toyoda K., Masui H., Cho M.

Advances in Space Research 68 ( 3 ) 1568 - 1581 2021.08

Language：English Publishing type：Research paper (scientific journal)

Electrostatic dust transportation is one of the fundamental sources for dust activity on airless planetary bodies. Even though a series of laboratory experiments have been performed to improve our understanding of the physics behind the electrostatic dust mobilization, there are several factors to investigate such as the launch angles, the lofted particle sizes, the traveling distance of the lofted grains, the initial acceleration to the launching velocities and so on. In this experimental study, an electron beam is used with 450 eV energy to produce secondary electrons to initiate lofting of the silica microspheres in the vacuum chamber, and the particle trajectories are recorded with a microscopic telescope and a high-speed camera. The dust samples are prepared as a mixture of particles with sizes from several micrometers to approximately 90.0 μm in radius. In addition, a polyimide tape with the adhesive surface is placed around the dust sample to collect the lofted particles up to approximately 10.0 cm distance. The collected silica microspheres are studied under the microscope to measure the size variation over the distance from the dust source. The experiment results show that spherical particles and residues effortlessly reach up to 10 cm distance, whereas the fluffy dust aggregates are observed particularly near the dust sample. In addition, the analysis of trajectories shows that the dust grains accelerate rapidly to their launching velocities below 12.0 ms due to the repulsion between the neighboring dust particles. Finally, the peak of the dust launching angle distribution is determined to be around 43.5–45° from the surface normal.

DOI： 10.1016/j.asr.2021.03.037

Scopus

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Sulphur-fuelled Surface Arc Thruster for Propelling Nanosatellites Reviewed International journal

Shimhanda S., Hiraka K., Inoue T., Toyoda K., Cho M.

Advances in Astronautics Science and Technology 4 ( 1 ) 39 - 46 2021.03

Difference in discharge threshold voltage between electron beam and ultraviolet environment Reviewed International journal

Kazuhiro Toyoda, Takaaki Sasaki, Mengu Cho, Mitsuru Okubo, and Kazuyoshi Seki

Journal of Spacecraft and Rockets 2020.10

Consideration on voltage rising in spacecraft during flashover discharge Reviewed International journal

Toyoda K.

Journal of Spacecraft and Rockets 57 ( 6 ) 1419 - 1421 2020.07

Sulphur-fuelled surface arc thruster for propelling nanosatellites Reviewed

Shimhanda S., Hiraka K., Inoue T., Toyoda K., Cho M.

Proceedings of the International Astronautical Congress, IAC 2020-October 2020.01

Language：English Publishing type：Research paper (international conference proceedings)

Pulsed electrothermal thrusters use kiloampere discharge currents for polytetrafluoroethylene (PTFE) ablation and sublimation. However, higher arc currents cause higher electromagnetic interference (EMI). A 10 J surface arc thruster (SAT), which adopts current regulating diodes (CRD), was developed that enables significant reduction in EMI. A CRD limits the discharge currents to 5 A in spite of the applied voltage. A low-melting-point sulphur propellant has been used that enables low discharge currents to efficiently ablate it and accelerate it electrothermally. In this paper, the near-term potential for elemental sulphur propellant in SAT is investigated. The advantages of sulphur with respect to PTFE are presented. First, we measured the pulse width of the main discharge. Then sulphur propellant proved superior to PTFE propellant in discharge duration. The mean pulse widths of PTFE and sulphur are 3.38 ms and 22.1 ms, respectively. Secondly, we measured the pressure rise in the vacuum chamber after each discharge. The mean pressure rises of PTFE, sulphur powder and sulphur solid are 0.43 mPa, 0.94 mPa and 1.9 mPa, respectively. Sulphur powder experienced the least intensity of discoloration in comparison with other propellants. The discharge initiator misfired frequently during PTFE ablation, but it ignited successively during sulphur ablation. Experimental results indicate sulphur is a suitable propellant for surface discharge propulsion, and for low arc currents is superior to PTFE.

Scopus

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100945416&origin=inward

Horyu-VI: International cubesat mission to investigate lunar horizon glow Reviewed

Orger N.C., Cho M., Iskender O.B., Lim W.S., Chandran A., Ling K.V., Holden K.H.L., Chow C.L., Bellardo J., Faure P., Santoni F., Circi C., Marzioli P., de Grossi F., Frezza L., Toyoda K., Masui H., Mariko T., Alarcon J.R.C., Yamauchi T., Kim S., Lim J.W.M., Potrivitu G., Laterza M.

Proceedings of the International Astronautical Congress, IAC 2020-October 2020.01

Language：English Publishing type：Research paper (international conference proceedings)

Interaction with the solar wind and UV/X-ray irradiation can cause the lunar dust to be electrostatically charged and mobilized all around the Moon, and light scattering by this dust cloud can be observed over the lunar terminator. This phenomenon, which has also been called the lunar horizon glow (LHG), still remains unexplained. The LHG observations using conventional lunar probes have limited observation opportunities and do not cover varying space weather conditions in cislunar environment such as strong upstream plasma flow and micrometeoroid flux that could enhance the lunar dust presence in the exosphere. The nanosatellite “HORYU-6” specialized in LHG observations will be put into lunar orbit to detect the light scattering above the lunar terminator. The proposed payload will perform multi-spectral imaging to monitor the lunar horizon several minutes before orbital sunrise or after orbital sunset for light scattering analysis. We show that we can obtain scientific results of lunar and planetary exploration using CubeSat at low cost and in a short period of time, and contribute to the development of lunar and planetary exploration in the future. The spacecraft will be developed jointly with universities in Singapore, the United States and Italy under the supervision of Kyushu Institute of Technology, with the aim of launching the SLS-2 rocket in the second half of 2022. Together with its own scientific objectives, the HORYU-6 mission will demonstrate the low thrust trajectory optimization by utilizing electric propulsion system together with other novel embedded technology demonstrations such as atomic clock, deep space navigation and communication with CubeSats.

Scopus

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85100916419&origin=inward

Difference in threshold voltage of arc inception between electron beam and ultraviolet environment Reviewed

Toyoda K., Kose S., Sasaki T., Cho M.

AIAA Scitech 2020 Forum 1 PartF 2020.01

Language：English Publishing type：Research paper (international conference proceedings)

As a charging method in ground experiments, an electron beam is often used to simulate high energy particles. In addition to this, a charging method using ultraviolet has been devised because charging by sunlight also occur in the space environment. Accordingly, ultraviolet were used for the discharge threshold measurement experiment of the solar cell, but the large difference of the threshold voltage was seen in two charging methods. The purpose of this research is to find out the cause of this large difference and to apply ultraviolet to charging and discharge experiment of space solar cell. We assumed that the charging potential of the cover glass edge of the solar cell was different in two charging methods and it caused the difference of the discharge threshold voltage. Therefore, we measured the surface potential focusing on the cover glass edge. In the experiment, a sample simulating the structure of the space solar cell was prepared and irradiated with ultraviolet or electron beam until the potential of the cover glass surface did not change overall. The surface potential of the cover glass edge at this time was measured with a contactless surface electrometer, and the results by two charging methods were compared. As a result, it was found that the surface potential at the cover glass edge was different in two charging methods. On the other hand, it was also found that measurement accuracy was low. We devised measurement method using Pockels effect which can measure potential directly or plan to improve measurement accuracy by improving sample because higher measurement accuracy is required to clarify the difference in charging.

DOI： 10.2514/6.2020-2012

Scopus

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85092349408&origin=inward

Consideration on voltage rising in spacecrafts during flashover discharge Reviewed

Toyoda K.

AIAA Scitech 2020 Forum 1 PartF 1 - 6 2020.01

Language：English Publishing type：Research paper (international conference proceedings)

An electrostatic discharge can cause a flashover discharge propagating on a solar array paddle. The flashover electron current flows from a solar cell (cathode) to coverglasses charged positively with respect to the cells. The return current flows from solar array circuits into spacecraft power unit via power cables. This is caused by blocking diodes connected on the positive side of solar array circuit. In the end, the flashover current passes through a bus capacitance inside the spacecraft. The amount charge of flashover current can increase the voltage in the bus capacitance. In this paper, the voltage rising due to flashover current is considered with the combination of flashover current and bus capacitance value.

DOI： 10.2514/6.2020-2011

Scopus

Other Link： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85092416924&origin=inward

Attitude Testing Platform in a Vacuum Environment for a Lean Satellite with an Electric Thruster Reviewed

Marcos Hernandez-Herrera, Phongsakorn Meemak, Hiroki Hisatsugu, Kotaro Hiraka, Jose Rodrigo Cordova-Alarcon, Sangkyun Kim, Kazuhiro Toyoda, and Mengu Cho

Journal of Small Satellites 8 ( 2 ) 849 - 858 2019.09

Electrostatic discharge experiment results on ground using experiment model of Horyu-IV Reviewed International journal

Fukuda H., Shimizu T., Toyoda K., Cho M.

Journal of Spacecraft and Rockets 56 ( 6 ) 1809 - 1815 2019.08

Guest Editorial Spacecraft Charging Technology Reviewed

Andersen A., Bodeau M., Cho M., Davis V.A., Dennison J., Donegan M., Ferguson D.C., Green N., Inguimbert V., Jun I., Lai S.T., Likar J.J., Minow J., Parker L.N., Roussel J.F., Toyoda K., Garrett H.B., Usui H.

IEEE Transactions on Plasma Science 47 ( 8 ) 3629 - 3630 2019.08

AOBA VELOX-IV: 2U CubeSat for the technological demonstration of lunar horizon glow mission Reviewed

Kim S., Orger N.C., Cordova-Alarcon J.R., Hernandez-Herrera M., Masui H., Yamauchi T., Toyoda K., Cho M., Duy Vu B.T., Vinh T.Q., Seng L.W., Hiang C.T.

Acta Astronautica 161 328 - 337 2019.08

Experimental investigation on silica dust lofting due to charging within micro-cavities and surface electric field in the vacuum chamber Reviewed

Orger N.C., Toyoda K., Masui H., Cho M.

Advances in Space Research 63 ( 10 ) 3270 - 3288 2019.05

Electrostatic Discharge Threshold on Coverglass Used to Protect Solar Cells in the Low Earth Orbit Reviewed

Khan A.R., Minh N.D., Toyoda K., Cho M.

IEEE Transactions on Plasma Science 47 ( 2 ) 1445 - 1452 2019.02

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Papers - TOYODA kazuhiro