著者

Yasuaki SAKAMOTO Kazuhide KURODA Shunsuke ONIBUCHI Susumu HARA

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.62, 2023 (Released:2023-08-30)

参考文献数

9

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Small rockets using hybrid rocket engines have been developed as a part of space development projects by student groups at various universities. The actively developed technologies include supersonic rockets and self-built engines. However, development based on aerodynamic technology has few precedents. In this paper, a case is described in which the Nagoya University Aerospace Flight Technology NAFT demonstrated attitude control technology, which is indispensable for rockets, by using aerodynamic technology. The main mission of the Masterpiece-05 Leidenschaft launch vehicle used for this launch demonstration was to achieve autonomous attitude control by rolling with movable fins. The goal was to roll the rocket by 45 deg after the engine burnout was stopped. The control law for the roll attitude control was proportionalderivative control, and the value of the gain was determined by estimating the torque in the roll direction generated by the movable fins using computational fluid dynamics. The launch took place during the Izu-Oshima Joint Launch Experiment (Izu-Oshima Space Event) held on November 9–11, 2018. The altitude and attitude of the airframe were logged. After stopping the roll of the airframe, attitude control was performed from 3.90 to 8.45 s after ignition. As a result, the phase difference between the roll attitude angle at the start of attitude control and the converged roll attitude angle at the end of attitude control was approximately 51.8 deg. The mission was confirmed to have been accomplished based on the numerical values of the roll attitude angle obtained from the data logger. These efforts are significant from the viewpoint of educational value in space engineering because there are few examples of extracurricular activities wherein students take such initiatives.

著者

Ryusei HAYATOMO Hiroyoshi YASUHIRA Haruki SASHIDA Kohdai ONO Kazuki HIRAYAMA Takuto IIJIMA Hironori SAHARA Yuya IKEDA Takeru YUZAWA Toshiaki IIZUKA Yusuke EGAWA Koh KAMACHI

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.55, 2023 (Released:2023-06-30)

参考文献数

17

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With the increasing usage of microsatellites in recent years, the demand for propulsion systems has also increased. Therefore, in this study, we developed a Microsatellite-Friendly Multi-Purpose PROPulsion system (MFMP-PROP) using 60 wt.% H2O2 as a basic propellant. MFMP-PROP can operate in the monopropellant mode for small impulse bit and the bipropellant mode for a relatively large thrust with a comparably high specific impulse. In this paper, the bipropellant mode is introduced and described, including reports on the progress concerning their research and development. As an approach to stable combustion, the effects of mixing ratio, preheating temperature, and mass flow rate on the operating characteristics were evaluated. As a result, we demonstrated a reliable and stable combustion range. The lifetime and continuous operating time were evaluated to investigate durability. As a result, 132 ignitions and 7,900 s of total operating time were achieved, during which the propellant consumption reached 1,375 g.

著者

Yusuke MATSUOKA Masato FUNATSU Takahisa KANEDA Yuki OYA

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.93, 2023 (Released:2023-12-21)

参考文献数

9

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When a sample return capsule enters the Earth's atmosphere, a strong shock wave is generated in front of the capsule and it receives severe aerodynamic heating. An ablation method is the effective thermal protection one to protect the capsule from the heating. In the future, capsules are expected to be larger and to increase reentry speed. Therefore, the capsules will be exposed to more severe aerodynamic heating. In this experiment, porous carbons with different pore diameters (5 μm, 10 μm, and 25 μm), and porous carbons impregnated with cyanoacrylate were used as test pieces. It was found that there were differences in wear time and wear behavior depending on the test pieces. Furthermore, the effective heat of ablation was calculated by conducting an experiment using an automatic position control system that can detect the tip of the test piece and control it to the target position. The effective heat of ablation of porous carbon impregnated with cyanoacrylate (5 μm) was about 2.8 MJ/kg.

著者

Takahiro SASAKI Hiroyuki OKAMOTO Yu NAKAJIMA Ryo NAKAMURA Toru YAMAMOTO

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.52, 2023 (Released:2023-06-30)

参考文献数

17

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Considerable research is being directed toward active debris removal (ADR) in space, especially by small, cost-effective satellites. In the descent phase, thrust vector control (TVC) is often utilized to maintain the satellite’s trajectory and thrust vector by gimbaling the thrust vector. A common challenge in performing TVC is that its effectiveness depends on the mass, moment of inertia and location of the thrusting point with respect to the center of mass. Since these properties change with fuel consumed during a mission, a designer needs to consider such parameters as they strongly affect the resulting dynamics. This paper introduces spacecraft dynamics with a gimbaled thruster and proposes an adaptive controller for TVC with model uncertainties. Through numerical examples, the effectiveness of the proposed controller is demonstrated for improved control performance.

著者

Naoki HIRAIWA Mai BANDO Shinji HOKAMOTO

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.48, 2023 (Released:2023-06-30)

参考文献数

23

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This paper proposes an algorithm to systematically search for a good sequence and the number of intermediate orbits in order to design the low-thrust minimum-fuel halo-to-halo transfer. The proposed algorithm applies successive convex optimization for the optimal transfer design, and initial guesses for the optimization are generated by beam search. In the beam search process, intermediate halo orbits that construct the initial guesses are chosen from a family of halo orbits so that they are located between the initial and final halo orbits. By determining the appropriate evaluation index for the intermediate orbit design, the proposed algorithm can collect local optimal solutions with a reasonable computational time. The obtained optimal transfers provide several options for the total △V and time of flight, which helps to find the suitable solution based on mission requirements.

著者

Yusuke YAMASHITA Takuya KOISO Ryudo TSUKIZAKI Kazutaka NISHIYAMA

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.21, 2023 (Released:2023-06-07)

参考文献数

21

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In microwave discharge ion thrusters, the plasma mode transition and hysteresis are two of the most important phenomena. The plasma mode-transition restricts the maximum thrust, whereas the hysteresis splits two mode of thrust in each flow rate. The previous thruster development and optical measurement indicates that there are two important parameters; the volume of magnetic confinement region where electrons are continuously heated by ECR and confined by magnetic mirrors, and waveguide plasma conditions. In this study, several kinds of thrusters that have different volume of magnetic confinement were tested. In addition, the enhancement of cut-off density inside the waveguide using larger diameter of waveguide was proposed. Experimental results show that the volume of magnetic confinement region is a key parameter for determining the maximum thrust. It was also found that the enhancement of cut-off is effective to eliminate the plasma hysteresis, whereas it does not affect the plasma mode transition. Hence, to further improve the thrust, one possible solution is to enhance the cut-off density at downstream of waveguide outside of magnetic field confinement region.

著者

Akane NISHIMURA Hirohide KATSUTA Yoshinori TAKAO Toshiyuki TSUCHIYA

出版者

International Symposium on Space Technology and Science

雑誌

Journal of Evolving Space Activities (ISSN:27581802)

巻号頁・発行日

vol.1, pp.7, 2023 (Released:2023-03-23)

参考文献数

13

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An ionic liquid electrospray thruster (ILEST) is expected as a propulsion system to control nano-spacecraft attitude and orbit in space. To produce high thrust, we propose a two-stage electrodes thruster which has an accelerator in addition to an extractor. We fabricated emitters on a silicon wafer and the two-stage electrodes on a glass substrate with through holes using microfabrication technologies. We confirmed that the fabricated ILEST emitted ions or droplets from the silicon emitters at near 2.0 kV. The maximum current in single-stage operation was -570 µA at 3.0 kV. With two-stage operation using the accelerator, ion emission happens at high voltage without conduction between the extractor and the accelerator. The results show the advantage of the fabricated two-stage electrodes. Currently, extracted ions were captured mostly at the extractor because of the poor alignment of the emitter silicon chip to the jig.