著者
五代 富文
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会誌 (ISSN:00214663)
巻号頁・発行日
vol.50, no.585, pp.215-218, 2002-10-05 (Released:2019-04-12)
被引用文献数
1
著者
庫本 正
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会誌 (ISSN:00214663)
巻号頁・発行日
vol.47, no.551, pp.264-271, 1999-12-05 (Released:2019-04-09)
参考文献数
36
被引用文献数
2
著者
松下 将典 高橋 秀幸 佐藤 泰貴 岩佐 貴史
出版者
一般社団法人 日本航空宇宙学会
雑誌
航空宇宙技術 (ISSN:18840477)
巻号頁・発行日
vol.21, pp.53-61, 2022 (Released:2022-09-29)
参考文献数
13

Membranes can be applied to deploy high-capacity, lightweight and large structures in space, such as solar sails, occulters, and sunshields. However, it is difficult to predict the shape of the membranes under low tension in orbit, mainly because gravity deflects the membrane on the ground experiments. We propose a ground-based experimental method to simulate the shape of the membrane in weightless conditions by placing the membrane in an aqueous solution. We developed a small experimental system and measured the shape of the curved membrane that floated in a sugar solution. The effectiveness of the experimental method was evaluated by comparing the experimental results with the results of geometrically nonlinear finite element analysis. In addition, these results were compared with the results of the suspended membrane without gravity compensation.
著者
井上 孝祐 上原 進 小紫 公也 荒川 義博
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.54, no.627, pp.168-174, 2006 (Released:2006-05-19)
参考文献数
20
被引用文献数
1 4

An experimental study on the energy conversion process of a continuous wave (CW) laser thruster is presented. The effect of the flow parameters on two dominant loss mechanisms of a CW laser thruster was investigated by using a CW CO2 laser with output power of 700W. The laser transmission and radiation from the laser sustained-plasma (LSP) were measured for several flow velocities and pressures, which were independently controlled. CCD camera was employed in order to observe the shape and position of the LSPs. We found that the energy conversion process is optimized when the LSP is in the vicinity of the focal point of the condensing laser beam.
著者
海老沼 拓史 楠 知通 阿部 俊雄 齋藤 宏文
出版者
一般社団法人 日本航空宇宙学会
雑誌
宇宙技術 (ISSN:13473832)
巻号頁・発行日
vol.8, pp.15-21, 2009 (Released:2009-08-05)
参考文献数
8

This paper describes the design and development of a dedicated GPS receiver for spin stabilized launch vehicles. The receiver is built around a commercially available low cost GPS chip set and operates an enhanced firmware specifically adapted for high dynamics applications. In order to keep tracking a sufficient number of GPS signals even during the spinning motion, we use multiple GPS patch antennas and space them equally apart each other around the cylindrical launcher body. A new signal combining scheme was developed to avoid deep fading in antenna gain pattern. This technique requires phase control to keep signals received on multiple antennas in phase with each other. A dualantenna GPS receiver was developed to evaluate the proposed signal combining algorithm. The result showed that the proposed algorithm was capable of providing stable and continuous signal tracking under a high-rate spinning motion while simple RF combining through a power combiner was failed.
著者
永尾 陽典 木部 勢至朗 清水 隆之 引地 誠
出版者
一般社団法人 日本航空宇宙学会
雑誌
宇宙技術 (ISSN:13473832)
巻号頁・発行日
vol.6, pp.37-45, 2007 (Released:2007-09-27)
参考文献数
12
被引用文献数
2 2

宇宙基地や宇宙往還機などが滞在するLEO では10km/s の速度でデブリが周回し,その数は記録されていないmm オーダーのものまで入れると4,000 万個ともいわれ,更に増え続けていると考えられている.これらの環境のもと宇宙機の構造側で最も考慮すべきとされるデブリは重量1g,速度10km/s とされるが,地上での試験を行うために用いる事ができる2 段式軽ガスガンでは速度は7km/s 程度までがほぼ上限である.一方,10km/s 以上の超高速試験では成型爆薬を用いた方法がある.そこで,著者らは10km/s の速度を安定的に出せる装置を開発したが,さらにプロジェクタイルを速度約7km/s で固体の状態のままで発射できるガスガンと,溶融化した状態となる成型爆薬方式との,それぞれの衝突現象の把握と,両者の差異の有無を確認する事を目的として,7km/s で1g 程度の模擬デブリの発射が可能な成型爆薬方式による射出システムを開発した.この装置の開発によって,ガスガンを用いた実験と成型爆薬方式による実験との関係を得る事が可能となり,5km/sレベルから10km/s レベルまで,固体デブリが衝突した時の構造への影響を正確に把握する事を目的としている.
著者
西山 和孝
出版者
一般社団法人 日本航空宇宙学会
雑誌
宇宙技術 (ISSN:13473832)
巻号頁・発行日
vol.4, pp.21-27, 2005 (Released:2005-11-19)
参考文献数
7

A completely new solar electric propulsion concept, the Air Breathing Ion Engine (ABIE), has been proposed for spacecraft drag makeup at very low altitudes, ranging from 150 to 200 km. ABIE scoops up neutral atoms and molecules traveling at an orbital velocity of approximately 8 km/s, ionizes them by means of an electron cyclotron resonance plasma source that is efficient in a wide range of low gas pressures, and accelerates the ionized air particles electrostatically to exhaust velocities larger than 100 km/s. The key technology of this thruster is the design of a propellant inlet which allows the incoming flow to enter the discharge chamber, yet it prevents the thermalized gas from escaping upstream. In this system, an air-breathing-type neutralizer may also be employed, in which case the need to carry on-board xenon propellant is eliminated and results in gains in payload mass if the mission duration is longer than 2 years. This technology should give researchers access to a part of the atmosphere that is currently very difficult to measure and is thus called the "ignorosphere." Promising applications other than aeronomy include science missions involving accurate gravity and magnetic field mapping, and high-resolution Earth surveillance.
著者
西澤 宇一 亀田 正治 渡辺 安
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.56, no.654, pp.315-323, 2008 (Released:2008-08-27)
参考文献数
12

The performance of a two-dimensional Mach 1.64 external compression air intake is investigated by computational fluid dynamics. The intake model consists of a 10-degree wedge and a subsonic diffuser. The flow in and around the intake with different configurations of the slit at the diffuser entrance is calculated to examine the effect of the configurations for pressure recovery and stability of the shock system. The numerical results indicate that the natural bleed fairly improves the intake performance at subcritical operation: It improves the maximum pressure recovery and the tolerance of the mass flow rate through the diffuser to guarantee the stability of the shock. The bleed mass flow rate strongly depends on the slit configuration. Large bleed mass flow rate increases the tolerance of the diffuser mass flow rate for the shock stability. However, the presence of the slit provides no gain in efficiency of the intake at supercritical operation.
著者
北村 圭一 葛生 和人 入門 朋子 野中 聡 藤本 圭一郎 福添 森康 嶋 英志
出版者
一般社団法人 日本航空宇宙学会
雑誌
航空宇宙技術 (ISSN:18840477)
巻号頁・発行日
vol.10, pp.43-50, 2011 (Released:2011-06-14)
参考文献数
23
被引用文献数
3 3

The Epsilon Launch Vehicle, scheduled to be launched in 2013, is currently under the development by JAXA (Japan Aerospace Exploration Agency). In this study, aerodynamic characteristics of the Epsilon Launch Vehicle are investigated by conducting both wind tunnel tests and numerical analyses at Mach 0.7. In order to examine accuracy of the measured drag, we probed the cavity pressure in addition to the base pressure, in contrast to our earlier work for Mach 1.5. The measured data indicated that the cavity pressure can be substituted by the base pressure or the static pressure within 3% error, which accounts for 1% error in the fore drag estimation. Then, the fore drag, calculated based on the static pressure, was used for CFD validation. Our CFD results of attack angles of 0 and 5 degrees showed fair agreement with the wind tunnel results, including the surface flow pattern, the fore drag and the normal force. Finally, aerodynamic characteristics of Epsilon Launch Vehicle at Mach 0.7 are extracted from the CFD results: 1) contribution to total forces was clarified for each part (e.g., flanges and attitude control units), 2) the normal force profile at Mach 0.7 showed comparable peaks with the Mach 1.5 case, in spite of the smaller separation regions near protuberant parts, and 3) the Reynolds number effect turned out to be minor within the range of the wind-tunnel and flight conditions.
著者
林 寛 碓井 美由紀 中山 宜典 清水 幸夫 西山 和孝 國中 均
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.55, no.647, pp.604-611, 2007 (Released:2007-12-27)
参考文献数
21
被引用文献数
1

An ion engine with 10,000sec-class high specific impulse is expected as primary propulsion for interplanetary space mission with extremely high delta-V, and needs high voltage for ion acceleration over 10kV. The microwave discharge ion source without solid electrodes can supply sophisticated technologies and simple composition on electrical isolation for such a high voltage. New electro-static grid made of carbon-carbon composite material was fabricated based on the numerical simulation of “igx” code. The “μ10HIsp” ion engine combining the ECR ion source, microwave discharge neutralizer, DC blocks, propellant isolators, carbon-carbon composite grid and so on generated successfully a plasma beam with 10,000sec specific impulse using 15kV acceleration voltage.
著者
宮本 侑斗 原田 明徳 ビクラマシンハ ナヴィンダ キトマル 宮沢 与和 船曳 孝三
出版者
一般社団法人 日本航空宇宙学会
雑誌
航空宇宙技術 (ISSN:18840477)
巻号頁・発行日
vol.13, pp.1-10, 2014 (Released:2014-02-13)
参考文献数
11
被引用文献数
3 7

Fuel efficient flight is demanded due to air traffic increase, environmental concerns and skyrocketing fuel prices. To achieve an effective futuristic air traffic management system, realization of TBO (Trajectory Based Operations) optimized from departure to arrival is aimed in CARATS (Collaborative Actions for Renovation of Air Traffic Systems). In this paper, 4-D trajectory of passenger aircraft is optimized for fuel minimization on the assumption that aircraft is not bounded by any air traffic control constraints. BADA (Base of Aircraft Data) model is adopted for aircraft performance model, and dynamic programming is used to calculate the optimal trajectory. The optimal trajectory is compared with airliner’s flight trajectory by evaluating fuel consumption, flight time and flight range. Examples show that considerable amounts of reduction in fuel consumption could be achieved by trajectory optimization compared to the estimated values of actual flights.
著者
小木曽 望 内海 智仁 室津 義定
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.50, no.586, pp.458-465, 2002 (Released:2003-09-02)
参考文献数
12
被引用文献数
1 1

This study is concerned with a shape optimum design of a propeller blade operating in a low Reynolds number range, 1.0–2.0×105. The objective is to minimize the power-required under the constraints on the thrust and the angle of attack in terms of chord length and twist angle distributions where the power-required is evaluated by 3-D panel method. The profile drag is also considered in the optimization, because the effect cannot be ignored in a low Reynolds number range. For calculation efficiency, the profile drag coefficient is approximated by higher order polynomials in terms of Reynolds number and angle of attack. The effectiveness of the proposed method is demonstrated by the design of a propeller blade of a human-powered aircraft. Additionally, effect of the profile drag is discussed by comparing the designs with and without considering the profile drag.
著者
丸山 祐一
出版者
一般社団法人 日本航空宇宙学会
雑誌
日本航空宇宙学会論文集 (ISSN:13446460)
巻号頁・発行日
vol.57, no.667, pp.309-316, 2009 (Released:2009-08-17)
参考文献数
18
被引用文献数
2

Two kinds of methods of explaining the physical mechanism of the Magnus effect are compared with each other and fully discussed. The first method uses Bernoulli's theorem and the fluid velocity difference between both sides of the body. The second one is based on the momentum theorem which relates the lift force with the fluid acceleration perpendicular to the uniform flow direction, which is caused by the asymmetry of separation points. It is shown that the latter method is preferable because it can be strictly applied to the real flow field containing both the rotational and the irrotational flow regions.