An effective estimation method of thermal contact resistances (TCRs) in a satellite thermal model is presented. In a general satellite thermal design, the accurate values of TCRs are initially unknown and must be determined to make the thermal model be consistent with experimental results. This determination process usually needs large cost because the appropriate TCRs have to be searched by try-and-error approach. In the presented method, the estimation of the TCRs is effectively performed by using the ensemble Kalman filter (EnKF), which can automatically provide optimum estimations of system state variables while assimilating the numerical model with the experimental one. By setting the TCRs to be the state variables in the satellite thermal model, the optimum estimations of the TCRs can be obtained as outputs of the EnKF. A numerical example of a simple small satellite is provided to verify the effectiveness of the presented method.

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The Advanced Solid Rocket is being developed by JAXA (Japan Aerospace Exploration Agency). Since its configuration has been changed very recently, its aerodynamic characteristics are of great interest of the JAXA Advanced Solid Rocket Team. In this study, we carried out wind tunnel tests on the aerodynamic characteristics of the present configuration for Mach 1.5. Six test cases were conducted with different body configurations, attack angles, and roll angles. A six component balance, oilflow visualization, Schlieren images were used throughout the experiments. It was found that, at zero angle-of-attack, the flow around the body were perturbed and its drag (axial force) characteristics were significantly influenced by protruding body components such as flanges, cable ducts, and attitude control units of SMSJ (Solid Motor Side Jet), while the nozzle had a minor role. With angle-of-attack of five degree, normal force of C_Nα = 3.50±0.03 was measured along with complex flow features observed in the full-component model; whereas no crossflow separations were induced around the no-protuberance model with C_Nα = 2.58±0.10. These values were almost constant with respect to the angle-of-attack in both of the cases. Furthermore, presence of roll angle made the flow more complicated, involving interactions of separation vortices. These data provide us with fundamental and important aerodynamic insights of the Advanced Solid Rocket, and they will be utilized as reference data for the corresponding numerical analysis.

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The educational hybrid-rocket was successfully launched and it also landed within the predicted area. Aerodynamic characteristics of the rocket designed by students of Tsukuba University were evaluated by the wind tunnel testing with the support of Tokai University. The flight path affected by the environmental condition, especially wind direction and velocity, was simulated with the original calculation program. The altitude of the rocket was measured with the optical equipment and the apex was 123 m although the calculation indicated 198 m. We expected that the insufficient filling or the volatilization of Nitrous oxide as an oxidizer led to this result. And then, the apex was verified with a function of the oxidizer filling ratio. The results showed that 81.2 % of the oxidizer volume in comparison with the firing test condition was accumulated in the tank at the launch.

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This paper presents a generic method for optimal motion planning for three-dimensional 3-DOF multi-link robotic manipulators. We consider the operation of the manipulator systems, which involve constrained payload transportation/capture/release. The task is solved in the presence of arbitrary multiple additional constraints. The solutions of the associated nonlinear differential equations of motion are obtained numerically using the direct transcription method. The direct method seeks to transform the continuous optimal control problem into a discrete mathematical programming problem, which is solved using a nonlinear programming algorithm. By discretizing the state and control variables at a series of nodes, the integration of the dynamical equations of motion is not required. The Chebyshev pseudospectral method, due to its high accuracy and fast computation times, was chosen as the direct optimization method to be employed to solve the problem. To illustrate the capabilities of the methodology, maneuvering of RRR 3D robot manipulators were considered. Their optimal operations were simulated for the manipulators, binded to move their effectors along the specified 2D plane and 3D spherical and cylindrical surfaces.

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Recently, environmental problems have been paid great attention in the world. According to the current report of ICAO, CO₂ emissions of aircraft to the total emissions will increase at an average annual rate of 3∼4%. Furthermore, stable supply of oil is becoming difficult. Without exceptions, those are hitting aviation industries. Therefore, in the near future, the time to shift from kerosene to liquid hydrogen (LH₂) as fuel of aircraft will come. An idea of supersonic transport (SST) fueled by LH₂ as one of the next-generation SST has been proposed by JAXA. The purpose of this study is to compare the weight, aerodynamics and cost of hydrogen fueled SST with those of kerosene fueled SST and to discuss its feasibilities. A possibility of two-bubble fuselage configuration is also evaluated.

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This paper describes solar paddle antenna proposed in the development of Kagawa Satellite "KUKAI." KUKAI is a mother-daughter pico-satellite for technical verification of a tethered space robot. The mother and the daughter satellites communicate respectively with the ground station by amateur radio frequencies. For the purpose of simple deployment system on orbit and antenna directivity suitable for KUKAI, solar paddle antenna mounted at the edge of a solar paddle is employed. After sufficient antenna adjustment on the ground, KUKAI was launched on 23 January 2009 by the H-IIA rocket from Tanegashima Space Center. The solar paddles were successfully deployed, and communication by the solar paddle antenna was successful.

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In the process of deployment of an inflatable structure, when the stiffness of the structure increases rapidly, especially at the final moment of deployment, a large reaction force is generated around supporting points with the main body of a spacecraft. It is important to minimize the reaction force when deploying in order to decrease the influence on the satellite attitude and strength of supporting points as much as possible. The purpose of this study is to attain a method of optimal deployment control that minimizes the reaction force generated around supporting part. In order to achieve the goal, feedback control experiments using an electromagnetic valve to adjust the inner pressure was done during deployment of inflatable tube. In addition, the effectiveness of the proposed method was also examined when applying it to the structure of the different size. As a result, it is found that the suppression of the reaction force is attained by about 80% compared with the case where this control is not applied, and the effectiveness of the proposed feedback control method of inner pressure was confirmed. Moreover, considering the volume, it is able to apply this control method even with different scale structures.

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This paper reports test results of active control of heat transfer performance of a small loop heat pipe (LHP) with a thermoelectric converter (TEC) in an atmospheric condition. The TEC is attached to a reservoir of the LHP to control the operating temperature by heating and cooling using a bipolar power supply. Tests were conducted by varying the evaporator power, the reservoir set point temperature, and the condenser sink temperature. The test results showed that the TEC is able to control the LHP operating with small electric power. The test results also demonstrated enhancement of the start-up success by maintaining a constant reservoir temperature during the start-up process. Forced shut-off of the loop operation by rapid heating of the reservoir was also demonstrated.

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Microsatellites are now in vogue in the world and propulsion will be desired for the more complicated space mission with them. We have been devoting ourselves to develop a propulsion system based on hydrogen peroxide solution with middle-level concentration and tested it for several years, and are now working on price reduction of the propulsion system with the view of a budget of satellite development. One of the key elements of the propulsion for the price reduction is a bladder to pressure liquid propellant, and we confirmed a COTS bladder is practicable with respect to storage performance of hydrogen peroxide and application way of pressure in this study.

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