N. Yamamoto, M. Miyoshi, H. Masui, Takashi Miyamoto, Nobutaka Munesada, H. Nakashima
The dependency of thrust performance on thruster configurations such as antenna length, antenna height, number of antenna, magnetic field configuration, and microwave frequency, was investigated with the objective of improving the thrust performance of microwave discharge ion thruster using antennas for uniform and dense plasma production. The experimental results showed that there was an optimum length of the antennas, and it was 3/4 times the wave length of incident microwaves. The ion beam current reaches its maximum value when the antenna was set at 2mm downstream of an electron cyclotron resonance layer. There was an optimum number of the antennas. This is due to the tradeoff between the coupling of plasma with microwave and the surface recombination on the antenna. The expansion of ionization zone was made successfully by changing magnetic field configuration. In addition, the thrust performance was slightly improved with increase in incident microwave frequency from 2.45GHz to 4.2GHz. A value for the ion beam current with 2.45GHz is compensated by high electron number density and less magnetized ions for the disadvantage of small plasma number density. Overall, the propellant utilization efficiency, ion production cost, and estimated thrust were found to be 0.62, 300W/A and 6.2mN, respectively at mass flow rate of 0.22mg/s for xenon, ion beam voltage of 1,500V and 2.45GHz microwave incident power at 32W.
{"title":"Improvement of Microwave Discharge Ion Thruster Using Antennas for Uniform and Dense Plasma Production","authors":"N. Yamamoto, M. Miyoshi, H. Masui, Takashi Miyamoto, Nobutaka Munesada, H. Nakashima","doi":"10.2322/JJSASS.55.546","DOIUrl":"https://doi.org/10.2322/JJSASS.55.546","url":null,"abstract":"The dependency of thrust performance on thruster configurations such as antenna length, antenna height, number of antenna, magnetic field configuration, and microwave frequency, was investigated with the objective of improving the thrust performance of microwave discharge ion thruster using antennas for uniform and dense plasma production. The experimental results showed that there was an optimum length of the antennas, and it was 3/4 times the wave length of incident microwaves. The ion beam current reaches its maximum value when the antenna was set at 2mm downstream of an electron cyclotron resonance layer. There was an optimum number of the antennas. This is due to the tradeoff between the coupling of plasma with microwave and the surface recombination on the antenna. The expansion of ionization zone was made successfully by changing magnetic field configuration. In addition, the thrust performance was slightly improved with increase in incident microwave frequency from 2.45GHz to 4.2GHz. A value for the ion beam current with 2.45GHz is compensated by high electron number density and less magnetized ions for the disadvantage of small plasma number density. Overall, the propellant utilization efficiency, ion production cost, and estimated thrust were found to be 0.62, 300W/A and 6.2mN, respectively at mass flow rate of 0.22mg/s for xenon, ion beam voltage of 1,500V and 2.45GHz microwave incident power at 32W.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129048189","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Masataka Shirako, Koji Araki, Y. Sugiyama, Hisayoshi Honda, Yosuke Nakamura, Y. Iwamaru, H. Tanahashi
The paper reports design process of a space boom to be installed in a 50kg-class micro-satellite, tentatively called as SOHLA-1. The total mass of the boom is 483g, while the length of the boom is 416mm. A spring-string type pin-puller was proposed. Vibration test with a bread-board model (BBM) of the boom leaded to an engineering model (EM) of the boom accommodated with a two-pin type pin-puller. Vibration test with the boom EM suggested some modifications to be made for a proto-type model (PM) of the boom. Vibration test, deployment test and thermal test on the boom PM confirmed feasibility of the flight model (FM) of the boom.
{"title":"Development of a Boom for a 50kg-Class Micro-Satellite and Vibration Test","authors":"Masataka Shirako, Koji Araki, Y. Sugiyama, Hisayoshi Honda, Yosuke Nakamura, Y. Iwamaru, H. Tanahashi","doi":"10.2322/JJSASS.55.406","DOIUrl":"https://doi.org/10.2322/JJSASS.55.406","url":null,"abstract":"The paper reports design process of a space boom to be installed in a 50kg-class micro-satellite, tentatively called as SOHLA-1. The total mass of the boom is 483g, while the length of the boom is 416mm. A spring-string type pin-puller was proposed. Vibration test with a bread-board model (BBM) of the boom leaded to an engineering model (EM) of the boom accommodated with a two-pin type pin-puller. Vibration test with the boom EM suggested some modifications to be made for a proto-type model (PM) of the boom. Vibration test, deployment test and thermal test on the boom PM confirmed feasibility of the flight model (FM) of the boom.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"13 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131859242","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes a method of early spacecraft anomaly detection by simultaneously estimating its states and parameters. We applied an extended particle filter algorithm in order to estimate not only states but also parameters. In this method, we incorporated artificial evolution of parameters and kernel smoothing of parameters into the ordinary particle filter algorithm. Each parameter is related to each state of the spacecraft components, so we can understand what is happening in the spacecraft by finding out parameters’ changing signs. We tested the algorithm on a simulation of spacecraft attitude motion.
{"title":"Anomaly Detection for Spacecraft by Estimating Parameters with Particle Filter","authors":"Kohei Goto, Y. Kawahara, T. Yairi, K. Machida","doi":"10.2322/JJSASS.55.355","DOIUrl":"https://doi.org/10.2322/JJSASS.55.355","url":null,"abstract":"This paper proposes a method of early spacecraft anomaly detection by simultaneously estimating its states and parameters. We applied an extended particle filter algorithm in order to estimate not only states but also parameters. In this method, we incorporated artificial evolution of parameters and kernel smoothing of parameters into the ordinary particle filter algorithm. Each parameter is related to each state of the spacecraft components, so we can understand what is happening in the spacecraft by finding out parameters’ changing signs. We tested the algorithm on a simulation of spacecraft attitude motion.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"1 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120862175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper proposes a new method which employs the optimal flight controls of a point mass model to a rigid body model in order to realize the optimal guidance controls for an autonomous UAV. In the first stage of this study, we had developed an UAV flight simulator. A point mass model as well as a rigid body model is incorporated into the simulation programs because it is utilized in order to obtain optimal controls by solving two-point boundary-value problems. All proper model parameters of the point mass model were estimated by simulations with the flight simulator. Four control inputs of the rigid body model were produced based on three control inputs of the point mass model. Both models’ simulation results of some flight maneuvers showed good correspondence and our approach was justified by solving a simple optimal control problem of an UAV.
{"title":"The Development of an UAV Flight Simulator and Its Application","authors":"T. Kinoshita, F. Imado","doi":"10.2322/JJSASS.55.309","DOIUrl":"https://doi.org/10.2322/JJSASS.55.309","url":null,"abstract":"This paper proposes a new method which employs the optimal flight controls of a point mass model to a rigid body model in order to realize the optimal guidance controls for an autonomous UAV. In the first stage of this study, we had developed an UAV flight simulator. A point mass model as well as a rigid body model is incorporated into the simulation programs because it is utilized in order to obtain optimal controls by solving two-point boundary-value problems. All proper model parameters of the point mass model were estimated by simulations with the flight simulator. Four control inputs of the rigid body model were produced based on three control inputs of the point mass model. Both models’ simulation results of some flight maneuvers showed good correspondence and our approach was justified by solving a simple optimal control problem of an UAV.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115324627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2007-07-05DOI: 10.14822/KJSASS.55.642_188
直樹 清野
{"title":"HTV与圧部（有人宇宙空間）構造開発の概要","authors":"直樹 清野","doi":"10.14822/KJSASS.55.642_188","DOIUrl":"https://doi.org/10.14822/KJSASS.55.642_188","url":null,"abstract":"","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"99 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124694486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper reports experimental studies on telescopic aerospikes with multiple disks. The telescopic aerospike is useful as an aerodynamic control device; however, changing its length causes a buzz phenomenon, which many researchers have reported. The occurrence of buzzing might be critical to the vehicle because it brings about severe pressure oscillations on the surface. Disks on the shaft produce stable recirculation regions by dividing the single separation flow into several conical cavity flows. The telescopic aerospikes with stabilizer disks are useful without any length constraints. Aerodynamic characteristics of the telescopic aerospikes were investigated through a series of wind tunnel tests. Transition of recirculation/reattachment flow modes of a plain spike causes a large change in the drag coefficient. Because of this hysteresis phenomenon and the buzzing, the plain spike is unsuitable for fine aerodynamic control devices. Adding stabilizer disks is effective for the improved control of aerospikes.
{"title":"Aerodynamic Characteristics of Telescopic Aerospikes with Multiple-Row-Disk","authors":"Hiroaki Kobayashi, Y. Maru, Tetsuya Sato","doi":"10.2322/JJSASS.55.329","DOIUrl":"https://doi.org/10.2322/JJSASS.55.329","url":null,"abstract":"This paper reports experimental studies on telescopic aerospikes with multiple disks. The telescopic aerospike is useful as an aerodynamic control device; however, changing its length causes a buzz phenomenon, which many researchers have reported. The occurrence of buzzing might be critical to the vehicle because it brings about severe pressure oscillations on the surface. Disks on the shaft produce stable recirculation regions by dividing the single separation flow into several conical cavity flows. The telescopic aerospikes with stabilizer disks are useful without any length constraints. Aerodynamic characteristics of the telescopic aerospikes were investigated through a series of wind tunnel tests. Transition of recirculation/reattachment flow modes of a plain spike causes a large change in the drag coefficient. Because of this hysteresis phenomenon and the buzzing, the plain spike is unsuitable for fine aerodynamic control devices. Adding stabilizer disks is effective for the improved control of aerospikes.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124897351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effect of Lateral Blowing for Flat Delta Wings with Various Planforms and a Rectangular Wing","authors":"K. Tadakuma, S. Aso, Y. Tani","doi":"10.2322/JJSASS.55.282","DOIUrl":"https://doi.org/10.2322/JJSASS.55.282","url":null,"abstract":"","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129944159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Mizoguchi, N. Iwata, Kentaro Hayashi, S. Aso, Y. Tani
An experimental study has been conducted to investigate the effectiveness of film cooling in hypersonic, high-enthalpy flows. Both air and nitrogen are used for a test gas and a coolant gas is helium. Injection mass fluxes are varied by changing total pressure of the coolant gas. The half-surface of a flat plate model with a blunt nose is coated with the thin film of silicon dioxide to obtain the dependence of heat fluxes by catalytic recombination effects. Heat fluxes are calculated by surface temperatures measured by coaxial thermocouples. In the case of dissociated air free stream, catalytic effects are observed in our wind tunnel. Experimental results show that thermal protection by film cooling is effective in chemically reactive flows. Non-dimensional heat fluxes and cooling lengths in the dissociated free stream are at the same level as in the nitrogen flows. With film cooling, heat fluxes on the non-coated surface are nearly as same as coated surface regardless of the wall catalysis.
{"title":"Film Cooling Effectiveness in High Enthalpy Flows","authors":"M. Mizoguchi, N. Iwata, Kentaro Hayashi, S. Aso, Y. Tani","doi":"10.2322/JJSASS.55.259","DOIUrl":"https://doi.org/10.2322/JJSASS.55.259","url":null,"abstract":"An experimental study has been conducted to investigate the effectiveness of film cooling in hypersonic, high-enthalpy flows. Both air and nitrogen are used for a test gas and a coolant gas is helium. Injection mass fluxes are varied by changing total pressure of the coolant gas. The half-surface of a flat plate model with a blunt nose is coated with the thin film of silicon dioxide to obtain the dependence of heat fluxes by catalytic recombination effects. Heat fluxes are calculated by surface temperatures measured by coaxial thermocouples. In the case of dissociated air free stream, catalytic effects are observed in our wind tunnel. Experimental results show that thermal protection by film cooling is effective in chemically reactive flows. Non-dimensional heat fluxes and cooling lengths in the dissociated free stream are at the same level as in the nitrogen flows. With film cooling, heat fluxes on the non-coated surface are nearly as same as coated surface regardless of the wall catalysis.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123988142","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Y. Maru, Hiroaki Kobayashi, Motoyuki Hongoh, Tetsuya Sato
In this paper, a concept of a new variable-geometry aerodynamics device, which is designated “Multiple-Row-Disk (MRD) device,” is introduced. The MRD device divides large separation region around the shaft of an aerospike into several small cavity flows with multiple disks arranged on the shaft. Experimental studies on aerodynamic characteristics of conical nose with axisymmetric cavities were conducted in order to evaluate a feasibility and a fundamental characteristics of the MRD device. It was found that the MRD device could improve not only drag characteristics compared to the conventional aerospikes, but also static longitudinal stability characteristics compared to the conical nose.
{"title":"Aerodynamic Characteristics of Conical Nose with Axisymmetric Cavities","authors":"Y. Maru, Hiroaki Kobayashi, Motoyuki Hongoh, Tetsuya Sato","doi":"10.2322/JJSASS.55.304","DOIUrl":"https://doi.org/10.2322/JJSASS.55.304","url":null,"abstract":"In this paper, a concept of a new variable-geometry aerodynamics device, which is designated “Multiple-Row-Disk (MRD) device,” is introduced. The MRD device divides large separation region around the shaft of an aerospike into several small cavity flows with multiple disks arranged on the shaft. Experimental studies on aerodynamic characteristics of conical nose with axisymmetric cavities were conducted in order to evaluate a feasibility and a fundamental characteristics of the MRD device. It was found that the MRD device could improve not only drag characteristics compared to the conventional aerospikes, but also static longitudinal stability characteristics compared to the conical nose.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131874932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We succeeded in determining a tri-axial ellipsoidal model of one LEO debris Cosmos 2082 rocket body, its rotational axis direction in the celestial sphere, a compositional parameter, its rotation period and its precession using only light curve data that was obtained by an optical telescope. The brightness of the LEO debris was monitored for 2 days. The method of the least squares fitting is applied to determine these values. The derived axial ratios of the LEO debris is 100:18:18, the coordinates of the rotational axis direction in the celestial sphere are R.A. = 305.8o and Dec. = 2.6o and its rotation period is 41 seconds. When the precession is considered, its amplitude and precession period are 30.5o and 29.4 minutes, respectively. These results show that optical light curve data are sufficient to determine the shape and the motion of LEO debris.
我们仅利用光学望远镜获得的光曲线数据，成功地确定了一个LEO碎片Cosmos 2082火箭体的三轴椭球模型、其在天球中的旋转轴方向、组成参数、自转周期和岁差。近地轨道碎片的亮度被监测了2天。采用最小二乘拟合的方法来确定这些值。推导出LEO碎片的轴向比为100:18:18，在天球内的旋转轴方向坐标为R.A. = 305.80, dec = 2.60，其旋转周期为41秒。考虑岁差时，其幅值为30.50 min，岁差周期为29.4 min。这些结果表明，光学光曲线数据足以确定近地轨道碎片的形状和运动。
{"title":"Shape and Motion Estimate of LEO Debris Using Light Curves","authors":"T. Yanagisawa, H. Kurosaki, A. Nakajima","doi":"10.2322/JJSASS.55.209","DOIUrl":"https://doi.org/10.2322/JJSASS.55.209","url":null,"abstract":"We succeeded in determining a tri-axial ellipsoidal model of one LEO debris Cosmos 2082 rocket body, its rotational axis direction in the celestial sphere, a compositional parameter, its rotation period and its precession using only light curve data that was obtained by an optical telescope. The brightness of the LEO debris was monitored for 2 days. The method of the least squares fitting is applied to determine these values. The derived axial ratios of the LEO debris is 100:18:18, the coordinates of the rotational axis direction in the celestial sphere are R.A. = 305.8o and Dec. = 2.6o and its rotation period is 41 seconds. When the precession is considered, its amplitude and precession period are 30.5o and 29.4 minutes, respectively. These results show that optical light curve data are sufficient to determine the shape and the motion of LEO debris.","PeriodicalId":144591,"journal":{"name":"Journal of The Japan Society for Aeronautical and Space Sciences","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123068198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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