Koji Tanaka

令和元年度宇宙科学に関する室内実験シンポジウムは、新型コロナウイルスの感染拡大防止のため開催中止。すべて書面発表になりました。資料番号: SA6000149001レポート番号: 1

<p>  At present, a demonstration experiment using small satellites is planned to realize solar power generation (SPS). In the demonstration experiment, it is necessary to accurately evaluate the beam shape transmitted from the satellites. The beam shape was reproduced using a two-dimensional least-squares pattern processing technique. In this paper, we showed that by using this satellite as a LEO and arranging the receiving stations in one dimension, simpler and more accurate measurements can be performed than before.</p>

2019 Symposium on Laboratory Experiment for Space Science (February 28 - March 1, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

<p>  One of the major problems for realization of solar power satellite (SPS) is the transportation of materials onto the orbit. From the viewpoint of the thermal and structural design including electronic and RF circuits of the power generation and transmission panel of the entire SPS, a bulk portion is required. However, the power generation system using the thin film solar array or the power transmission array antenna system can be realized by a thin panel structure. We are studying the combination of bulk structure and expandable thin plate structure with power generation or antenna function for the purpose of improving the storage efficiency of parts of SPS in the rocket fairing and reducing the number of transportations.</p><p>  In this paper, a space demonstration of hybrid SPS consisting of bulk structure and expandable frame structure and simulation on deformation and vibration of the hybrid structure are described.</p>

<p>  Currently, demonstration experiments using small satellites are planned to realize space solar power generation (SPS). In the demonstration experiments, it is necessary to accurately evaluate the shape of the beam transmitted from the satellite. For this reason, it has been studied to install a plurality of receiving stations on the ground, measure their levels, and reproduce the beam shape. In this report, we report the reception station arrangement by using the pattern processing method using footprint measurement and two-dimensional least squares method.</p>

平成29年度宇宙科学に関する室内実験シンポジウム (2018年2月26日-27日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県資料番号: SA6000123014

2018 Symposium on Laboratory Experiment for Space Science (February 26-27, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

2018 Symposium on Laboratory Experiment for Space Science (February 26-27, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

第13回宇宙環境シンポジウム (2016年11月1日-2日. 情報通信研究機構 本部 国際会議室), 小金井市, 東京デブリ衝突に起因する電力ハーネスの持続放電および地絡・短絡故障といった電気的損傷は, 比較的衝突頻度の高い直径1mm以下のデブリでも発生しうる. そのリスクを正しく評価することは, 衛星に適切なデプリ防護設計を施す上で重要である. 本講演では, 特に太陽電池パドル裏面のハーネス単線に着目し, 従来研究よりも実環境に近い衝突条件および回路構成を用いた衝突実験の結果について進捗を報告する.形態: カラー図版あり資料番号: AA1630038013レポート番号: JAXA-SP-16-010

2017 Symposium on Laboratory Experiment for Space Science (February 27-28, 2017. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

2017 Symposium on Laboratory Experiment for Space Science (February 27-28, 2017. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

平成28年度宇宙科学に関する室内実験シンポジウム (2017年2月27日-28日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県資料番号: SA6000095014

<p>  Currently, the model of Space Solar Power Systems (SSPS) constructed from power generation and transmission panels is considered feasible models. This model made from a lot of panel units which have solar panels and microwave antenna array with different side. SSPS orbits on geostationary satellite orbit, so positional relation of sun and satellite will change cyclically. And it cause satellite's cyclic thermal deformation. Controlling deformation is important problem to realize efficient power transmission, because flatness of satellites influence the power transmission efficiency of microwaves. We describe experimental result of carbon nanotube actuators (CNA) aimed to control angular among the panel units for keeping flatness of satellite.</p>

2016 Symposium on Laboratory Experiment for Space Science (July 23-24, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

平成27年度宇宙科学に関する室内実験シンポジウム (2016年2月23日-24日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)相模原キャンパス), 相模原市, 神奈川県資料番号: SA6000055040

2016 Symposium on Laboratory Experiment for Space Science (July 23-24, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

<p>  A SSPS has got attention as one of the solutions for energy and environmental problems of the human society. Solar Power satellite (SPS) will have very huge space structures with a size of several km and super-light weight giant power generation systems of several GW. So we have studied the lightweight power generation system that is based on the thin film technologies. In order to realize the weight reduction of the thin solar array for the SPS, new space technologies are important. CIGS thin film solar cell can be expected the highest conversion efficiency in various thin-film solar cells. Study of the power generation system in the case of using the CIGS solar cells for SPS is performed. We describe experimental results of the measurement of the characteristic change of the solar cell due to space environmental factors. And we examined the power generation system by using experimental results.</p>

<p>  SSPS is a large-scale power generation satellite that is constructed from power generation and transmission panels. Solar arrays will be mounted on the power generation side and generate electricity by the sunlight. Microwave antennas will be mounted on the transmission side and transmit energy to the earth by the microwaves. Power transmission side will always face to the earth. Cyclic thermal deformation will occur in the power generation and transmission panel because the irradiation conditions of the panel by the sunlight are cyclically changed. Thermal deformation in the panel will decrease the power transmission efficiency. So we have been developing the flatness controlling of the large-scale antenna panel of SPS using carbon nanotube actuators. We describe the experimental results of generating power by CNA and prediction of figure of CNA.</p>

In this paper, we describe the thermal characterization of a multifunctional hybrid photovoltaic panel for the conversion of sunlight into microwave that is used in a solar power satellite. We designed a practical configuration of the hybrid panel and investigated the thermal characteristics by experiment and numerical analysis. First, thermal-vacuum test using a prototype panel was conducted to obtain practical thermal resistances between each layers of the panel. Using the obtained thermal resistances, we then simulated daily temperature variation and thermal deformation during an orbit. The simulation results show that the deformation is maintained within allowable range in the present panel configuration; panel temperature is, however, too low when top and bottom surface do not receive sunlight.

Solar power sail that is being developed by JAXA as a planetary exploration spacecraft utilizes a combination of electric and photon propulsion system. The solar power sail requires a super lightweight flexible power generation system that uses thin film solar cells. We are developing a mounting method of the thin film solar cells on the membrane of the sail. Major issues of our study are shape control and connection between thin film solar array and thin film electrical wiring harnesses. We describe experimental results of shape control by oxide sputtering on the polyimide film and thin film solar cells and evaluation results of trial production of the thin film solar array connected with the thin film flexible wiring harnesses by heat sealing.

5th Space Debris Workshop (January 22-23, 2013, Chofu Aerospace Center, Japan Aerospace Exploration Agency (JAXA)), Chofu, Tokyo, JapanSpace debris is recognized as a serious threat to man's utilization of space. When debris collide the spacecraft, plasma will be generated and may make a impact on the spacecraft's equipments. To simulate the debris impact against the spacecraft, we carried out the experiments on the detection of the generated plasma by the hypervelocity impacts concerning the thin sheet materials using a two stage light gas gun and a rail gun accelerator of the Institute of Space and Astronautical Science. We observed phenomena when the projectile collided a target using a high-speed video camera, plasma probes and spectral photo sensors. Figure 1 shows a bright cloud of the impact experiment. After the projectile impacted against the target, a bright cloud was generated and moved both forward and backward directions from the target. Results of the experiments were compared with the estimations by our simple impact model for thin sheet targets.Physical characteristics: Original contains color illustrations

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