Now, in order to elucidate phenomena of high velocity, high velocity launching equipment, such as single stage gas gun, powder gun, and two stage gas guns are used. Generally, powder gun and two stage gas guns can launch a projectile high mass compared with a single stage gas gun. But, the working hours for cleaning the inside of a launch tube are required after launching a projectile, and since gunpowder is used, the deterioration of equipment is large compared with a single stage gas gun. On the other hand, a single stage gas gun can prepare launching projectile in comparatively short time. Moreover, there is an advantage that equipment degradation is small. In this study, the single stage gas gun which can be launched to a portable type and all the directions is developed. And the experimental result which launched various projectiles using the single stage gas gun is reported.

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[in Japanese]

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ExplodingWire-Pulsed Plasma Thruster (EW PPT) is the satellite thruster using a wire explosion. Wire explosion is the phenomenon that wire is exploded by thermal expansion due to low-voltage pulse current from capacitor bank. The produced expansion gasses after exploding a wire contribute as propulsion of thruster. But, it is not clear about wire explosion with low-voltage, low-vacuum state and short Al thin wire. The purpose of this paper is to record the phenomenon by using HPV-1 and measure impulse bit by pendulum. As a result, impulse bit (I_<bit>) is 2900μN・sec with the wire of Al which diameter is 0.2mm.

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Japan Aerospace Exploration Agency (JAXA) has conducted Small Demonstration Satellite (SDS) program in order to offer chances of demonstrating state-of-the-art technology and components timely with low cost. As the second satellite of SDS program, Small Demonstration Satellite-4(SDS-4) was successfully launched as the piggyback satellite of GCOM-W 1 on 18th May 2012. This paper reports the Flight Model Environmental test results for Small Demonstration Satellite-4.

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Since 2006, Japan Aerospace eXploration Agency (JAXA) has promoted the small demonstration satellite (SDS) program to demonstrate newly developed components, and advanced space technologies on orbit. The JAXA establishes the standard satellite bus for SDS program's purpose. This paper describes the development results and the flight results of SDS-4, which has been launched in May 2012.

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[in Japanese]

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A Simplified analysis method, which can evaluate structural vibration properties of reusable launch vehicle, is considered a useful tool in the preliminary design phase. From this standpoint, we are developing a simplified wing vibration model by unsymmetrical finite plate element which corresponds to the wing structure with unsymmetrical cross section. In this paper, we are proposing a four-node plate element with unsymmetrical cross section based on the Bathe's MITC4 plate element. Demonstration analyses of the hollow double delta wing by our elements and their accuracies obtained by them are shown.

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Large deployable space membrane structures are developing in recent years as Gossamer spacecraft for solar-sail, sun shield, and etc. To design the deployable membrane structures, the structural characteristics are significant to examine the deployment configuration, vibrational and dynamic properties of the membrane structures. However, the initial deformation on the membrane due to the folding line and wrinkle with plastic deformation is not negligible for evaluating the mechanical properties because it is very large with respect to the membrane thickness. This paper investigates the effects of relatively large initial deformation of membrane on the vibration properties numerically under the assumption that the initial deformations are random that has a band spectral of wavelength observed in the solar sail "IKAROS". Finally, it was revealed that the initial deformation on the membrane affected the vibration properties of the membrane drastically.

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This paper deals with three-dimensional attitude control of spacecraft equipped with four thrusters whose directions are fixed to the spacecraft. The adopted four-thruster-configuration is very useful, because it can generate independent torques around the three principal axes of the spacecraft in spite of only four thrusters. This paper designs a controller based on a sliding mode control theory, because the theory is known to have robustness to modeling errors and external disturbances. Then, the control torques required for the sliding mode control are distributed to the four thrusters based on the nominal model of the spacecraft. Finally, the effects of the modeling errors are investigated in numerical simulations.

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Tethered satellite consists the two bodies connected through long tether, so it has the characteristic of being easy to be subject to the influence of vibration. In this paper, we propose the method of making a tethered satellite stable with sliding mode control, in order to suppress the vibration , when the satellite tether is deployed or retrieved.

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JEMRMS was launched in 2008, and is used for conveyance and exchange work of experimental equipments or containers, and its positioning performance and operability are very good. JAXA is carrying out research and development of a intra-vehicular human support robot. This paper gives study results on intra-vehicular robot supporting crew activity in space.

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The feasibility of a novel method for shape control of a reflector based on surface accuracy analysis using a stereo vision is demonstrated through experiments. In the control procedure, intentional deformations are added to a reflector surface by using surface adjustment mechanisms and the corresponding changes in surface accuracy are analyzed from the measured surface shape using an optical shape measurement system. Then the control inputs for the shape correction of the deformed reflector are directly determined from the information on the surface accuracy. Some experiments are performed and their results show that deformations of the reflector are corrected properly by the developed method when its shapes are measured at appropriate points.

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The shape measurement method of space structure is necessary. In this study, the method by using photometric stereo is examined experimentally with high-precision object. The experimental results show influences which measurement distance, element interval, illuminance, angle of incidence and size of measurement range have on the error of estimated configuration. The method of dividing measurement range is proposed and the usefulness of the method is proved.

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This report deals with shape measurement of inflated membrane. Conventionally, we have performed shape measurement of inflated membrane using laser displacement sensor. Lately, we introduced a three dimensional photo-grammetric system. To show the effect of photo-grammetric system, the results is compared with using laser displacement sensor.

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[in Japanese]

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Spatial distribution characteristic of the out of plane displacement of winkled membranes was investigated through the statistic analysis for the experimental results of the rectangular wrinkled membranes under shear loadings. The out of plane displacement of wrinkled membranes, held fixed at top and bottom edge and subjected to shear loading at top edge, were treated. The analysis results show that the spatial distribution of the out of plane displacement of the membranes does not follow the normal distribution and log-normal distribution. However, focusing on the average and the standard deviation of the out of plane displacement of the membrane, it turned out that these statistics follow theoretical models such as normal distribution and log-normal distribution.

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This paper addresses the simultaneous optimum design for the high precision space antenna considering the structural system and the controller. The simultaneous optimization for the rib-stiffened shell antenna is demonstrated, where the objective function is the RMS surface error, and the design variables are the thickness of the shell, the diameter of the rib, and the location and the output of the controller. Finally, the higher surface precision is obtained by the simultaneous optimization than the surface precision of the antenna design optimized separately for the structure and the controller.

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[in Japanese]

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[in Japanese]

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Pulsed Plasma Thrusters (PPT) have simply structure. Therefore small and light thruster can be developed at low cost and short time. Although PPT is low thrust and low propulsion efficiency. In our laboratory, we develop a new thruster which gets high thrust by using Metal powder explosion. In this study, we describe the behavior of Exploding Metal Powder at applying high voltage. We carry out experiments to which spraying condition of propellant is changed under conditions whose voltage and capacitor of the capacitor bank is 280V and 5440μF. As a result, we got the performance of I_<bit>:6692μN・sec, I_<sp>:1364sec and, η:22%.

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A surface shape measurement for two sub-regions of the spherical mirror model whose surface shape was processed with 10x10^<-6> m accuracy was performed by using the grating projection method with a phase-shift method and a sampling moire method, and technical issues on the whole field shape measurement proposed in the past studies, which synthesizes several measurement results on sub-regions to measure the large space structures, was investigated. Comparing the synthesizing results of the measurement data to the actual surface feature of the mirror models, characteristics of the synthesizing results were discussed.

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There have been recently proposed high-precision planar or parabola antennas through the deployment of flat or curved panels. The surface error induced by the misalignment at the connecting devices between the panels could not be negligible for such high-precision deployable antenna structures. In such a case, the uncertainty caused by the gap (fit error) in the devices, e.g. the gap between the shaft and the hole in the rotation mechanisms, should be estimated theoretically to evaluate the total accuracy of the structure. This paper discuss the formulation of the multi-body dynamics of the deployable structure which can take into account the uncertainty of the deployment devices such as hinges and joints and estimate the influence of such uncertainty on the shape accuracy of the structure.

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[in Japanese]

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[in Japanese]

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Recently, deployable membrane structure has been applied to deorbit mechanism for small satellite. One of the typical examples is deployable membrane system with the use of inflatable tubes or convex tapes as extension booms. The ground experiment results on the deployment of the conceptual models of the membrane structures are reported as well as the numerical analysis of their deployment dynamics in this paper.

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[in Japanese]

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Data assimilation is a generic technique which combines numerical simulation results with experimental data. In this paper, the ensemble Kalman filter (EnKF), which is categorized as sequential data assimilation techniques, is investigated when applied in fmite element analysis. The EnKF is a nonlinear extension of the standard Kalman filter, where a priori state estimates are provided by using the Monte Carlo method of nonlinear physical simulations. The estimates obtained in the EnKF can inherit many of the nonlinear properties of a priori state estimates. Through a simple numerical experiment, the effectiveness of the EnKF is examined.

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To meet advanced science missions, large and precise support structures such as truss structures are needed. Temperature and shapes change depending on solar radiation. As a result, the structure lost its preciseness. In this research, pointing accuracy of the truss structure on orbit is discussed. To control the shape, artificial thermal expansion caused by heater is used instead for mechanical actuators. Control systems without mechanism have high reliability because heater has no sliding parts. To maintain pointing accuracy on orbit, preview control method in this paper is expected to be more useful than feedback control methods.

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[in Japanese]

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[in Japanese]

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A Conceptual design of "Space Colony" for long-term residence is reported in this paper. As constraint conditions, micro gravity and high vacuum are considered in the structural design. Although such conditions are constraint, they have possibilities to be utilized for further innovative human life style which can not be realized on the ground. Especially, the environmental condition of micro gravity may have great impact to the life style from the viewpoint of mobility and immobility. In this paper, we propose some conceptual designs of the space colony utilizing micro gravity and discuss its characteristics.

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The motivation of this manuscript is feeling of strangeness that words of security and safety are widely used as a pair word in Japan. In addition, for a large-scale and complicated system such as a spacecraft system, safety requirement should be defined not only in the field of engineering, but also in the field of social science. It means that social attitude to safety, security and risk has a large effect on the large-scale and complicated system. This manuscript discusses the attitude to safety, security and risk on development of a spacecraft system.

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