Ryudo Tsukizaki

令和4年度宇宙輸送シンポジウム（2023年1月12日-13日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)) , 相模原市, 神奈川県 Space Transportation Symposium FY2022 (January 12-13, 2023. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan In the 3D-printed resistojet that the authors are working on, it is necessary to provide an electrical contact point at a high temperature part considering the limitations in 3D printing. So far, we have made some prototypes of flat contact type, tapered contact type, and screw type. In addition, as a new attempt, we also describe design guidelines for banana plug type that contact with radial surface pressure. 資料番号: SA6000184068 STEP-2022-016

Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher delta O-18, Delta O-17, and epsilon Cr-54 values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10's of km), <2.6 Myr after CAI formation. Subsequently, the Ryugu progenitor planetesimal was fragmented and evolved into the current asteroid Ryugu through sublimation.

令和3年度宇宙科学に関する室内実験シンポジウム（2022年2月28日-3月1日. オンライン開催) 2022 Symposium on Laboratory Experiment for Space Science (February 28-March 1, 2022. Online Meeting) 資料番号: SA6000178002 レポート番号: 2

令和3年度宇宙輸送シンポジウム（2022年1月13日-14日. オンライン開催) Space Transportation Symposium FY2021 (January 13-14, 2022. Online Meeting) 非化学推進優秀学生賞 資料番号: SA6000173064 STEP-2021-025

令和3年度宇宙輸送シンポジウム（2022年1月13日-14日. オンライン開催) Space Transportation Symposium FY2021 (January 13-14, 2022. Online Meeting) 資料番号: SA6000173068 STEP-2021-029

JAXA’s asteroid explorer Hayabusa2 completed its operation near the asteroid 162173 Ryugu, which started in June 2018, and carried out a maneuver away from the asteroid on November 13, 2019. In the outbound operation, the total delta-v performed by its ion propulsion was about 1,015 m/s, the space powered flight time reached 6,515 hours, 24 kg of propellant xenon was consumed, and 42 kg remained. On the return trip, 2,400 hours of operation was carried out in two parts, from December 2019 to February 2020 and from May to August 2020. Trajectory correction maneuver TCM-0 was carried out with one ion thruster from September 15 to 17, 2020, which was the last operation of the ion engine system, followed by several TCMs by chemical propulsion. The capsule returned to Earth on December 6, 2020. The total delta-v in the round trip was about 1.3 km/s, and the powered flight time was 9,398 hours. After consuming 31 kg of propellant xenon, 35 kg remained, a series of close flyby with an L-type asteroid 2001 CC21 in 2026 and rendezvous with a fast rotator asteroid 1998 KY26 in 2031 has been proposed as an extended mission of Hayabusa2 and its ion engine were restarted on January 5, 2021. The cumulative operating times for the four ion thrusters are 6,996, 2,880, 9,220, and 8,941 hours, respectively. 12,632-hour powered flight by the ion engine system produced about 1.7 km/s delta-v. An engineering model of Hayabusa2 neutralizer has been subjected to ground durability tests since the summer of 2012 prior to launch. 75,277 hours have passed by the end of September 2021, and it is still operating without failure and testing is ongoing.

Space Transportation Symposium FY2020 (January 14-15, 2021. Online Meeting)

Space Transportation Symposium FY2020 (January 14-15, 2021. Online Meeting)

Space Transportation Symposium FY2020 (January 14-15, 2021. Online Meeting)

Space Transportation Symposium FY2020 (January 14-15, 2021. Online Meeting)

Space Transportation Symposium FY2020 (January 14-15, 2021. Online Meeting)

Space Transportation Symposium FY2019 (January 16-17, 2020. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Space Transportation Symposium FY2019 (January 16-17, 2020. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

令和元年度宇宙輸送シンポジウム（2020年1月16日-17日. 宇宙航空研究開発機構宇宙科学研究所（JAXA)(ISAS)）, 相模原市, 神奈川県資料番号: SA6000147068レポート番号: STEP-2019-019

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

Copyright © 2019 by the International Astronautical Federation (IAF). All rights reserved. An MPD (Magneto-Plasma-Dynamic) thruster requires the input of a large amount of power, 100 kW to 1 MW, and it is difficult to operate in a steady state. Therefore, MPD thrusters are operated in quasi-steady state with a pulse generated by a PFN (Pulse Forming Network). However, there are two ambiguities regarding the steady state of the discharge. First, the discharge time of a PFN, typically 0.5 to 1.0 ms, is insufficient to quantitatively verify discharge steady state. Second, the unsteady region at the end of a discharge can lead to error in the evaluation of the steady state of the entire discharge. In this presentation, we propose a pulsed power supply which generates more rectangular pulses that are several longer and fewer unsteady regions than those of a PFN to evaluate the quasi-steady state of an MPD thruster. In an operation test with a 1.0 ms discharge, the unsteady regions was reduced from 0.532 to 0.085 ms, and the flat-top region which should be evaluated was increased from 0.393 to 0.880 ms. Therefore, the ratio of the evaluation time to the discharge time was improved from 42% to 91%. Using the power supply, we operated an MPD thruster and obtained the discharge time characteristics of the discharge waveform and the thrust performance by sweeping the discharge time from 1.0 to 5.0 ms. As a result, the discharge current was maintained at 900 ± 100 A for each discharge time and the thrust was in the range of 0.3 ± 0.02 N, which is interpreted as being constant. These results confirm the quasi-steady state of the MPD thruster operation from 1.0 to 5.0 ms. In addition, we also investigated the influence of residual gas in a vacuum chamber on the quasi-steady state by sweeping gas supply timing.

Space Transportation Symposium FY2018 (January 17-18, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Space Transportation Symposium FY2018 (January 17-18, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Space Transportation Symposium FY2018 (January 17-18, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Space Transportation Symposium FY2018 (January 17-18, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Space Transportation Symposium FY2018 (January 17-18, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

© 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. This paper is a study to reveal the mechanism of the roll torque in the gridded ion thrusters. Through the space operation of ion thrusters, a small torque is observed around the thrust axis. In order to reveal the mechanism of the roll torque, the authors performed the laser-induced fluorescence and 2DPIC simulation. As a result, the torque of the experiment and the simulation showed good agreement. From the results of experiments and simulation, it was found that the cause of roll torque is drift inside the ion source, the misalignment of the grid, and leakage magnetic field in the ion beam.

Space Transportation Symposium FY2017 (January 18-19, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Space Transportation Symposium FY2017 (January 18-19, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Space Transportation Symposium FY2017 (January 18-19, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan