This paper is a progressive report for the space demonstration of bare electrodynamic tape tether which is one of the advanced technologies in space. The demonstration is the international campaign of Japan, USA, Europe and Australia and the first science and engineering experiment in the world extending bare electrodynamic tape tether in space. The tether is deployed successfully from the S520-25 sounding rocket launched on 31st August 2010 by JAXA. Results of the engineering experiment are reported in this paper on the system to deploying the tape tether to the length about 130 m which is the world record for the deployment of tape tether.

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The experiment of charged particle collection experiment by bare electrodynamic tape tether was performed by using JAXA's sounding rocket S-520-25 on August 31, 2010. This was the first experiment of bare tether in space in the world. This paper shows the outline of the experimental apparatus and the initial experimental results of the verification of bare electrodynamic tether operation and the charged particle collection theory. As experimental results, Valuable data of electron collection by the induced electromotive force and ion collection by a space potential probe in space were obtained, although charged particle collection data by tether and boom were not obtained by a trouble of high voltage power source.

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This paper reports a development and demonstration of inflatable extension boom in the experiments of the ISAS/JAXA sounding rocket, S-520-25. The inflatable extension boom developed by the authors is the longest in ones with conductive part to work as an electrode for collection of electrons surrounding the rocket. S-520-25 sounding rocket was launched in August 31, 2010, and 5 experiments including an extension of the inflatable boom were conducted. The inflatable extension boom and its system worked very well with no problem to form 4-m-long electrode in space.

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This paper describes the space experimental result for the Tethered Space Robot -S (TSR-S) on the sounding rocket “S-520-25.” A tethered space robot is a new type of space robot connected to tether. The major advantage of the tethered space robot is that its attitude can be controlled under tether tension by its own link motion. The S-520-25 was launched on August 31. The TSR-S experiment was started at 285 seconds after the launch. The launch lock was unlocked and the robot was deployed by the springs. The tether was extended and kept its tension, and the attitude control of the robot was performed. The disturbed vibration of attitude was suppressed, and also the desired attitude was controlled by link motion of the robot.

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While analyzing membrane dynamic characteristics, Multi Particle Method (MPM) has several advantages than Finite Element Method (FEM). This paper presents the influence of spring allocation on the analytical value of flexural vibration using MPM. Two MPM models, one is using parallelogram element and the other is using rectangular element, and FEM model as a reference are used for comparison of the accuracy evaluations. Flexural vibration phenomenon is selected for the comparison of the eigenvalue analysis under applying a shear force upon rectangular membrane. Analytical accuracies of the eigenvalue of the membrane flexural vibration are found to be very much dependent on the shear force value and the spring allocation of the analytical model of MPM.

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A thermal mathematical model plays an important role in operations on orbit as well as spacecraft thermal designs. The thermal mathematical model has some uncertain thermal characteristic parameters, such as thermal contact resistances between components, effective emittances of multilayer insulation (MLI) blankets, discouraging make up efficiency and accuracy of the model. A particle filter which is one of successive data assimilation methods has been applied to construct spacecraft thermal mathematical models. This method conducts a lot of ensemble computations, which require large computational power. Recently, General Purpose computing in Graphics Processing Unit (GPGPU) has been attracted attention in high performance computing. Therefore GPGPU is applied to increase the computational speed of thermal analysis used in the particle filter. This paper shows the speed-up results by using GPGPU as well as the application method of GPGPU.

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Flight trajectory of a passenger aircraft is critical for the research and development of future air traffic control system. Generally, though, flight data are closed to the public view. In this paper a simple method is introduced to estimate flight trajectories using a commercial GPS receiver at a cabin of an in-flight airplane and numerical weather data. Barometric pressure altitude and Mach number were evaluated at the study. Results prove that airplanes follow almost exactly the predetermined airway and cruising altitude. Maximum deviation was recorded only at a magnitude of several dozen meters.

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In order to image ion thruster beam optics with high resolution, a two-dimensional visualized ion thruster had been modified and improved. Judging from the visualization experiments with a tele-centric lens and a digital camera, it was confirmed that the behavior of visualized beam optics were well accorded with electrostatic acceleration theory. Since both the ion beam shape and plasma sheath shape can be obtained, in addition to the grid currents, the visualized images of this thruster is useful for the multifaceted validation of ion beam optics codes, and is of value for improvement of prediction accuracy of ion thruster durability life.

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We developed a laser energy transmission system for a disaster data collection helicopter. A demonstration test-flight was successfully done in a large indoor arena at Kobe. The laser energy transmission system (max output power : 580 W/cw) was tracking on a helicopter for a long-time flight at a distance of 30 m. This test flight shows the possibility of tools for a collecting data of a natural disaster and a nuclear power plant disaster.

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Space debris environment evolutionary model for the geosynchronous Earth orbit region, GEODEEM, developed by Kyushu University was upgraded for better understanding. This paper explain the key features of this upgraded model. One of keys of this upgrade is that all satellites larger than 10 cm in size are tracked individually. The benefits of this upgrade are: 1) collision accidents can be estimated based upon one-by-one collision probabilities, and 2) more realistic scenarios like removing certain objects from orbits can be applied. This paper also present the latest prediction of future space debris environment from 2008 to 2108. The model indicates that explosion is the main debris production mode in next 100 years.

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A surface shape measurement of a polyimide film was performed by using the Grating Projection Method (GPM) in order to discuss applicability of the GPM for measuring the surface shape of the permeable and highly reflective thin membranes of space structures. The measurement results showed that the GPM can measure the permeable and highly reflective flat polyimide film with the same measurement accuracy of the mat metal plate except for the specularly-reflected area of the polyimide film. It was shown that the optical property of the polyimide film such as the diffuse reflector and permeability did not affect the measurement accuracy, while measurement variations were affected. In addition, through the measurement of the polyimide film with wrinkles and slacks, the GPM can successfully capture the local wrinkles and slacks of the polyimide films in the diffuse reflector area. From the results, an applicability of the method to measure the surface shape of the polyimide film was shown.

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This paper describes a study of combustion process of LOX/hydrogen rocket engine at supercritical pressure by macroscopic model. The model consists of rate controlling one by mixing process of supercritical temperature oxygen with hydrogen. Here, local mixing efficiency of the propellants is evaluated by Rupe's mixing index. And if we assumed that the local combustion rate was related to the Rupe's index as the exponential function, then the pressure distribution of combustion along chamber length calculated by the presented model could duplicate the pressure distribution observed by the experiments.

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In the Part-2, it is continuing to examine the presenting combustion model to LOX/methane combustion at supercritical pressure. Then the model is expanded to apply for design and evaluation method of actual rocket combustion chamber at supercritical combustion pressure.

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In this study, we investigate the effects of partition in a cavity on heat flux in a hypersonic ramp flow by carrying out both CFD and experiment. The experiment was conducted at M=8.1 at the shock tunnel of Nagoya University. It is found from results that the separation region becomes larger by installing a partition inside the cavity. As a result, the interaction between the separated hypersonic laminar boundary layer and the back wall of the cavity weakens, and the heat flux at the cavity back wall can be reduced by up to 50% compared with the case without partition. Moreover, it is made clear that the heat flux on the partition sidewall increases and that its cross-sectional average is almost the same as the maximum heat flux in the case without cavity.

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In this study, we have succeeded to generate the shock wave in 3 mm inner diameter tube by using diaphragmless driver section that we developed. The laser differential interferometer is constructed for the measurement of the shock wave propagating in the small diameter tube. The Mach number of the shock wave and the density ratio across the shock wave can be calculated by the interferometric signal obtained from the shock wave measurement. The Mach number distributions along the axial direction of the tube and the relation between the shock wave location and the time are obtained. As a consequence, it is confirmed that the behavior of the shock wave propagating in small diameter tube shows remarkable deviations from the theory and Brouillette's model.

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Aerodynamic characteristics of asymmetrically wing tip damaged aircraft have been investigated experimentally, numerically and analytically. This study is aimed to simulate unexpected airframe damage during flight such as a bird strike. Wind tunnel studies were conducted at a Reynolds number of 4.83 × 10⁵ based on a wing mean aerodynamic chord. The results indicated decreases in lift and drag, increases in pitching moment and rolling moment for the wig tip damaged configuration. Good agreement between wind tunnel experiments and numerical simulations was observed. Further studies based on a vortex lattice method and a lifting line theory were also conducted. It was confirmed that the observed rolling moment increase is caused by the lift loss of the wing tip damage. Furthermore, a distinctive feature of yawing moment decrease for the wing tip damaged configuration was observed both by the wind tunnel study and the numerical simulation. The vortex lattice method and the lifting line theory confirmed that this yawing moment decrease is caused by the movement of wing center line due to the reduced wing span length.

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A space debris shield for use with spacecraft and satellites was designed. A space debris shield is required to have high defense performance and be lightweight. In this paper, the pressurized wall in the shield composition was made into a double wall structure, and we considered inserting a liquid layer into the shield between these walls. First, the numerical analysis conditions of aluminum alloys of shield composition materials were established from reverse analysis using the ballistic limit equation of a Whipple shield. Using the scaled-down liquid shield, the liquid layer thickness was investigated by comparing the numerical analysis and impact tests that used a two-stage light gas gun. Next, the ballistic limit curve of a real-size liquid shield was examined using the numerical analysis. From these results, it was found that the liquid layer in the debris shield substantially slowed the velocity of incoming debris fragments.

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The performance of tank devices, such as porous metals and a metal fiber, on liquid propellant retention was evaluated under microgravity environment. IKAROS carries the gas-liquid equilibrium propulsion system which stores propellant as liquid phase in a storage tank and expels only gaseous propellant from the tank. Surface tension in pores of tank devices holds liquid propellant in them. As a result of microgravity experiments, it was found that the performance on liquid retention is higher than that estimated from results of bubble point experiment, and it strongly depends on the existence of bubbles in liquid propellant. From the results of the experiment, this paper proposes the location of porous metals in the storage tank to prevent bubbles from remaining with propellant consumption.

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Optimal trajectory design for reentry flight is studied by using Dynamic Programming (DP) method. DP is selected to make use of its ability of generating the optimal trajectory in real time as well as its simplicity to handle inequality constraint conditions for the trajectory optimization. The large amount of calculations to reduce discretization error in case of fewer control variables than the state variables is one of the drawbacks, but it is solved with two proposed techniques of Augmented Control Variables (ACV) method and the Least-error Grid-point Selection (LGS) method.

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This paper describes on study of optimizing design for rocket combustor of LOX/LH₂ engine at supercritical combustion pressure. Specifications of the target engine are the expander cycle one which having thrust of 1 MN at combustion pressure of 10 MPa. Optimization procedure of design is followed by author's formerly presented scheme. That is five cases as to the injection element and two cases as to the combustion chamber contraction ratio are selected as the candidates. Then combustion performance and combustion stability including low frequency and high frequency stability margin are evaluated. The combustion processes and heat flux distribution along the chamber axis are calculated by author's formerly presented supercritical combustion modeling. Low frequency stability is evaluated by Szuch model and by Heidmann model for high frequency instability respectively. Consequently the optimal dimensions and configurations of the injector and the combustor were obtained.

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This paper focuses on a collision risk of a tether system against other satellites. The tether system in this paper means a spacecraft for orbital debris removal using an electro-dynamic tether, and is expected to prevent the population growth of orbital debris in the low Earth orbit region. However, the tether system may encounter a high collision risk because of its thin and long configuration. Therefore, there is a possibility that the tether system collides with other orbiting satellites when the tether system conducts a mission of orbital debris removal. This paper estimates the collision probability and the success rate until the orbital debris removal mission is over and describes factors contributing to the reduction in the mission success rate.

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