Curriculum Vitaes
Profile Information
- Affiliation
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
- J-GLOBAL ID
- 201801018289126150
- researchmap Member ID
- B000325823
Research Areas
3Research History
5-
Apr, 2019 - Mar, 2020
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Apr, 2018 - Mar, 2019
Education
3-
Apr, 2010 - Mar, 2014
Awards
1-
Mar, 2024
Papers
19-
Space Science Reviews, 220(1), Jan 24, 2024 Peer-reviewedAbstract Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum $\varDelta $V capability of $600\text{ ms}^{-1}$. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule.
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IEEE Signal Processing Magazine (to be published), 2024 Peer-reviewed
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Journal of Microelectromechanical Systems, 31(5) 802-812, Oct, 2022 Peer-reviewedWe present a self-deformable flexible tweezer capable of simultaneous mechanical handling and electrical measurements. The tweezer has a soft cantilever with the dimensions 2 mm x 8 mm x 75-100 mu m, and undergoes self-deformation. The device is shown to be successfully capable of detecting electrical signals by gently touching the surface and grasping a spherical bead. The device demonstrated the lowest working voltage (1.5 V-DC), force suitable for soft gripping, and curvature radius of 2 mm, that was one of the smallest values compared to that of similar state-of-the-art devices. The device was fabricated using a unique and highly reliable process that was specifically developed to produce flexible cantilevers with novel ionic polymer-metal composites (IPMCs). The materials used were poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) and an ionic liquid (IL). The PVDF-TrFE/IL gel was prepared using acetone as the solvent and the gel was coated with silver nanowires as the electrodes. The actuator with a length of 8 mm and containing 50 wt% IL yielded the largest bending displacement of 7 mm and minimum curvature radius of 2 mm at 1.5 V-DC.
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IEEJ Transactions on Sensors and Micromachines, 142(1) 8-12, Jan 1, 2022 Peer-reviewed
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IEEE Pervasive Computing, 20(3) 9-17, Jul 1, 2021
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IEEE Transactions on Semiconductor Manufacturing, 34(3) 270-277, 2021 Peer-reviewedLead authorCorresponding author
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IEEE Transactions on Semiconductor Manufacturing, 34(3) 256-261, 2021 Peer-reviewed
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Sensors and Actuators A: Physical, 112502-112502, Dec, 2020 Peer-reviewed
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IEEJ Transactions on Sensors and Micromachines, 140(1) 31-36, Jan, 2020 Peer-reviewedLead author
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IEEJ Transactions on Sensors and Micromachines, 139(8) 271-276, 2019 Peer-reviewedIn this article, we propose a device with multiple small pores, which are locally integrated with individual electrodes. The application is particle measurement using Coulter’s method, using the integrated local electrode on each pore. Coulter’s particle counter can achieve high resolution measurement; however, the method had sensitivity and throughput tradeoff problem in reducing measurable particle size. The system can locally observe current around the pore and thereby parallel measurement becomes possible while keeping high sensitivity. The fabricated pore size were 400 nm, 1.0 µm, and 1.5 µm. Spontaneous water flow was achieved with 1.5 µm device, and current dip attributable to Coulter’s principle was observed.
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Sensors and Materials, 31(8) 2481-2496, 2019 Peer-reviewed
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IEEE Geoscience and Remote Sensing Letters, 15(8) 1234-1238, Aug, 2018 Peer-reviewed
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IEEJ Transactions on Sensors and Micromachines, 138(7) 307-311, Jul 1, 2018 Peer-reviewed
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Sensors and Actuators, A: Physical, 275 75-87, Jun 1, 2018 Peer-reviewedThis paper presents a versatile chip-level wireless driving method for microelectromechanical system (MEMS) actuators. A MEMS actuator is integrated as an electrical component of a coupled LCR resonant circuit, and it rectifies the energy sent through an ultrahigh-frequency (UHF) radio frequency (RF) wave. Two types of actuators were remotely driven using the proposed method: thermal (bimorph) actuators used as the R component and capacitive (comb-drive) actuators used as the C component of a resonant receiver circuit. We demonstrated the remote actuation of a 13 Ω thermal actuator transferring 7.05 mW power with a power efficiency of 15.8%. This was achieved using coupled 500 μm diameter 5.5-turn planar coil antennas over a distance of 90 μm. When an impedance-matching configuration (Zo = 50 Ω) was used, the efficiency over a distance of 65 μm was measured to be 55.6%, which was 8.2 times greater than that of simple inductor coupling. The proposed method can be applied to future deployment scenarios, where fragile MEMS are placed on top of a system and must directly interface with the environment (thus, being prone to break). The authors propose to fabricate MEMS and energy receiver circuits monolithically on a chip, and place them on another energy transmitter chip. Thereby, the MEMS chip can avoid electrical feedthrough so that (a) the MEMS chip is easily replaceable if it breaks, and (b) the MEMS chip can move beyond wiring cable limitations. Four features are underlined in the article: (1) MEMS itself can rectify the RF energy owing to the fact that the governing equation of the MEMS actuator involves the square of the voltage and/or current, thereby, ensuring higher system-level efficiency than any other RF transceiver circuits using additional rectifying components (e.g., diodes). (2) Both the transmitter and receiver use coils of the same design, whose sizes are equivalent to those of the MEMS actuators (hundreds of micrometers). Moreover, they can be operated at UHF, owing to the much higher self-resonant frequency (fs > GHz) when compared to conventional transmitters (fs ≈ MHz). In addition, by using LCR resonant circuits, it is possible to not only (3) increase the transmission efficiency but also (4) multiply the driving voltage of the capacitive MEMS actuator, because of LC resonance. Voltage multiplication is quite useful for electrostatic MEMS operations because the movement is proportional to the square of the voltage across the MEMS capacitance. Comprehensive designs, implementations, and demonstrations of wireless operation are presented in this paper, for both thermal (resistive) and electrostatic (capacitive) actuators. Remote operation includes on–off-keying for MEMS without mechanical resonance and amplitude modulation of sinusoidal signals to stimulate the mechanical resonant frequency of MEMS.
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IEICE TRANSACTIONS ON ELECTRONICS, E100C(5) 490-495, May, 2017 Peer-reviewedLead authorWe propose a wideband reconfigurable circular-polarized single-port antenna to realize high-density linear integration for use in ground penetrating radars. We switch PIN diodes at a T-shaped probe to change its polarization. The forward-and reverse-biased probes work in cooperation to generate circular polarization. Experiments demonstrate the working bandwidths of 20.0% and 18.6% in the left-and right-hand polarization states, respectively, with 7.2 GHz center frequency. They are wider than those of conventional reconfigurable single-port circular-polarized antennas.
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IEEE GEOSCIENCE AND REMOTE SENSING LETTERS, 13(12) 2029-2033, Dec, 2016 Peer-reviewedLead authorPolarimetric synthetic aperture radar is expected to distinguish wet snow from bare ground. However, since both of them show surface scattering, which is sensitive to incidence angle, it often fails in the distinction in mountainous areas. In this letter, we propose an adaptive distinction method using quaternion neural networks. In the ALOS-2 data, we find a monotonic and nonlinear dependence of the degree of polarization on the incidence angle. Then, we feed multiple-incidence-angle teacher information in the learning process. The distinction results of the proposal present higher accuracy than those of the conventional Wishart distinction and a quaternion neural network without the incidence angle information.
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UNISEC Space Takumi Journal, 6(62) 14-28, Jul, 2016 Peer-reviewed
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TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN, 14(ists30) Pf{\_}45-Pf{\_}50, 2016 Peer-reviewed
Presentations
53-
34th International Symposium on Space Technology and Science, Jun 6, 2023
Teaching Experience
1-
Apr, 2024 - Present基礎電気回路 (明治大学)
Professional Memberships
3Research Projects
3-
科学研究費助成事業, 日本学術振興会, Apr, 2023 - Mar, 2026
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科学研究費助成事業 若手研究, 日本学術振興会, Apr, 2021 - Mar, 2025
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科学研究費助成事業 特別研究員奨励費, 日本学術振興会, Apr, 2018 - Mar, 2020
Other
1-
プロジェクトマネージャーとして参加した、はやぶさ2相乗りである超小型宇宙機ARTSAT2：深宇宙彫刻 DESPATCHの開発及び運用の成果報告書。久保田晃弘氏との連名。
