This report deals with deflection measurement of a inflatable membrane structure subjected to internal pressure loading. Conventionally, we have performed deflection measurement of the structure using laser displacement sensor. Lately, we introduced Kuraves which is a three-dimensional photo-grammetric system. To show the effect of the photo-grammetric system, the results is compared with using laser displacement sensor.

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A continuous surface shape measurement using the grating projection method is carried out to capture the complicated surface profile of the vibrating membranes with high spatial resolution. A vibrating behavior of the polyimide film, which is induced by an impact loading, is measured. The size of the polyimide film is 0.50 m × 0.50 m and thickness is 25 × 10^<-6> m. The measurement results show that the surface profile of the vibrating membranes is successfully captured by the continuous surface shape measurement using the grating projection method in exact detail. This paper also reports effects of the wrinkling phenomena on vibration characteristics of the membrane from the view points of a wave propagation process and a stationary vibration process.

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[in Japanese]

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This study investigates the robustness of a space reflector structure that consists of radial ribs and hoop cables that is connects to the back-up deployable structure by a central hub, cercumference stand-off struts and tie cables. The reflector surface shape is controlled by deforming the radial ribs by applying the proper cable tension. The design problem is to achievie the rib structure with an ideal deformation shape under the prescribed cable tensions. In addition, the shape adjustability by changing cable tensions is required for handling uncertainty on the actual environment condition. This study addresses the design problem by adopting the robust multiobjective optimization approach, where the surface shape error and the shape error sensitivity with respect to the cable tensions are used as multiple objective functions. Investigating Pareto solutions obtained from the two-objective and then the three-objective function problems, effects of cable tension variations on the surface shape error and the robustness are discussed.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Piezoelectric actuators are important parts for a smart reconfigurable reflector system and the actuators have to survive the shock loads experienced during launch. Impact tests of a piezoelectric actuator were conducted to evaluate the shock resistance of piezoelectric actuators. A failure of the piezoelectric actuator was observed after experiencing the shock load (QT level). In order to investigate the cause of the failure, the actuator was disassembled and characteristics of each peizo cells were measured. The results indicated that only the center cell was broken and it caused the actuator to malfunction. The other cells were health and retained good performance.

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This report deals with a derivation of heat conduction equation for plate bending analysis and an application of the thermal buckling problem of a thin plate. In the plate, temperature distribution of the direction perpendicular to the plate surface is assumed to be linear function. A finite element formulation of a thermal buckling problem of plate is also performed. As an application of our formulation, a thermal buckling problem of the plate subjected to local heating on the plate surface is analyzed. We can obtain buckling temperature from the finite element analysis. Also, under the transient analysis of temperature, we can estimate when the buckling occurs.

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Technical terms relating to spin dynamics of spacecraft, such as nutation and precession, are differently used in space engineering (especially in the design and operation of satellites) and in classical and celestial dynamics. In some cases, their usage is totally opposite. The difference is thought to come from the difference of viewpoint in defining the dynamic phenomena corresponding to the terms. Many textbooks of space engineering, however, follow the usage in classical dynamics without referring to the generally or traditionally accepted usage by practical space engineers. As an unfortunate consequence, confusion sometimes occurs in real and practical scenes of space activity. In this presentation, the usage and viewpoint of these terms in both space engineering and classical/celestial dynamics are reviewed, and their typical usage is compared for several examples of motion.

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In this study group, the impact test to a small satellite and the component of space apparatus was conducted using simple impact equipment. In this study, Shock material used by simple impact equipment was changed and this study considered the influence of the source of a shock. Stainless steel, brass, and aluminum were used as a shock material. The time history of acceleration was acquired as an experimental result. Moreover, Shock response spectrum was performed and the influence of shock material was considered. At this shock speed, it had influence of shock material. The case where stainless steel is used for shock material was the largest in the shock response spectrum.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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We have been developed LED visible light communication (VLC) Technology Satellite 'ShindaiSat' (Japanese nickname GINREI). GINREI was launched on February 28, 2014 as a secondary payload of main satellite GPM (Global Precipitation Measurement) by Japanese H-IIA rocket. By challenge several times after launched, we have successfully observed the LED light from the satellite by naked eyes and optical devices on the ground. In order to observe this LED light from the satellite on the ground, attitude of the satellite is required to be controlled by actuators. GINREI has magnetic torquers and reaction wheels as the attitude control actuators constituting attitude control system. By using these actuators, GINREI has been controlling to be stable. So, I will describe about the operation Status by controlling the attitude of satellite used magnetic torquers and reaction wheels on the satellite orbit on this paper.

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We have developed micro satellite "ShindaiSat" (Japanese nickname GINREI) at Shinshu University. GINREI was launched into a circular orbit of 400 km altitude and 65 deg. inclination by H-2A rocket on February 28, 2014 as a secondary payload of main satellite GPM(Global Precipitation Measurement). GINREI is a scale of 35kg and 40cm-class micro-satellite and the main mission is a visible light communication (VLC) using LED as light source between satellite and ground station. We obtain a basic data of atmospheric influence and confirm the feasibility of VLC. This paper describes Operational Status of GINREI.

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[in Japanese]

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TSUBAME is a 50kg microsatellite developed by Matunaga Lab. at ISAS/JAXA and Tokyo Institute of Technology, and was launched and released into a Sun-synchronous orbit on November 6, 2014. TSUBAME automatically deployed solar array paddles and performed the sun pointing sequence after the rocket separation. Before the launch, attitude determination and control subsystem of TSUBAME must be designed and verified to satisfy that even in the worst case scenario, TSUBAME can point to the sun and balance power electricity in 30000s after separation, if not, it loses power and switches to hibernation mode, performing only the battery charging. In this paper, Monte Carlo simulation is conducted for the attitude control behavior after separation using HiLS and Flight model of TSUBAME, and shows a low probability of the power shortage occurring in consideration of precise electric power estimation.

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Matunaga Laboratory at ISAS/JAXA and Tokyo Institute of Technology has developed a 50kg class micro-satellite called TSUBAME. In this paper, some of improvements of EPS at flight model phase are reported. Specifically, how to estimate depth of discharge by measuring cell voltage, how to manage a battery pack and passive cell balancing with resisters are focused.

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Dynamic vibration absorbers are frequently used to reduce and control excessive vibration in a wide number of applications such as bridges, engines and turbines. The premise of the vibration absorber is to transfer energy from the vibration source to the absorber mass by matching the frequency of the vibration source and excitation frequency of the absorber. However, as vibration in dynamic structures is highly variable, this study examines a variable dynamic vibration absorber where the system vibration can be tuned using an electromagnetic absorber placed between two permanent neodymium magnets. The absorber is tested onboard the fairing of a sounding rocket as part of the ARLISS Extreme 2014 program in Nevada, USA. This paper presents history and theory of variable vibration absorbers, system calculations, design and experimental results from the rocket flight.

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[in Japanese]

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This paper shows the design concept and the preliminary report for the low-accuracy three-axis stabilization results of the newly developed standard micro satellite system. The standard bus system is developed by the University of Tokyo and NESTRA (next generation space system technology research association) supported by the Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program). The satellite system tries to be straightforward to achieve cost-effective and short development period. The standard satellite systems are used as the bus system of three satellites launched in 2014, which are UNIFORM-1, HODOYOSHI-3, and HODOYOSHI-4. All of them have been achieved the low-accuracy three-axis stabilization, by dealing with the unexpected problems with the use of the modified operational plans. This paper also performs the comparison of the on-orbit results of three satellites and discusses the design feasibilities of the proposed bus system.

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This paper analyzes an application of adaption methodology in attitude control system for microsatellite. The control method is based on MPP (modified Rodrigues parameters) feedback control principle. The adequate adjustments of the magnitude of a discontinuous control are discussed here for the state trajectories are in and out of sliding surface. This control methodology is based on the equivalent control application and will reduce control action magnitude to the minimum possible value. The simulation results show the efficiency and feasibility of the proposed control method.

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[in Japanese]

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In this report, positioning system on planet such Mars to support the planetary explorer activity efficiently is described. The authors conducted a positioning system by specifying solar orbit plane using sun tracking mechanism from observer and more, the authors propose the specifying solar orbit plane by extraction of satellite outline and satellite position at night-time such as sun direction is under the horizon. To verify the constructed positioning system for the night-time, the authors execute the simulated experiment on the earth by using extraction of moon outline, the results obtained from the simulated experiment are evaluated.

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In this paper, a method for automatic operation of satellites using multiple ground stations is proposed. In the former part of this paper, a new ground station system which optimizes the use of multiple ground stations, and central software called "Scheduler" and "Sequencer" which is substitute of operator is proposed. The "Scheduler" schedules operation tasks and control the whole operation sequence automatically. The "Sequencer" executes operation tasks such as sending of antenna angle and radio frequency to remote ground station.

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