In this study, an investigation of an exotic mixture of non-hazardous materials was conducted both in the solid and liquid states, which produced higher heat releases through chemical reactions augmented by low-power continuous wave lasers. Numerical evaluation of exothermic energies, or heat release, through chemical reactions of the target propellants was conducted with a chemical equilibrium calculation code. The results showed that the reaction temperature for B-mixed PTFE was 500 K higher than raw PTFE. In liquid propellants, the highest reaction temperature of over 2000 K was obtained for HFE at low specific energy of 3 kJ/g.

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SIMPLE (Space Inflatable Membranes Pioneering Long-term Experiments) is one of the five mission payloads of MCE (Multi-mission Consolidated Equipment), which is among the series of Expose Facility experiments on Japan Experiment Module (JEM) in ISS (International Space Station). MCE was launched on board HTV-3 in July 2012 and was installed to the Exposure Facility. Following the checkout operations of the MCE, SIMPLE bus system went under initial workout. SIMPLE consists of three experimental sub-mission equipments: IEM (Inflatable Extension Mast), IST (Inflatable Space Terrarium), and IMP (Inflatable Material Panel). After the initial workout of the SIMPLE equipment, the extension of IEM was performed on August 17, 2012, followed by the deployment of IST, and the start-up of IMP monitoring, all in success. The details of the sequence throughout the development to initial on-orbit experimental phase of the SIMPLE project are given. The experiments are now under way in the steady operational phase. The current status and issues are briefly outlined.

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Cyclic tensile tests of a quartz fiber cable assembly for a deployable antenna reflector on satellite was performed. The cable assembly showed non-linear tensile behavior in the first cycle, which caused large residual displacement after unloading. In the following cycles, relatively linear tensile behavior was observed as compared with that in the first cycle. Displacement at allowable maximum loading, however, increased in each cycle with increase of number of cycles. To study the causes of the non-linear irreversible tensile behavior, the quartz fiber cable assembly was divided into two parts, i.e. straight segment and loop segment, and those were tested individually. The straight segment showed non-linear tensile behavior in the first cycle and residual displacement after unloading. In the following cycles, almost linear tensile behavior was observed and incremental displacement was not developed. By contrast, the loop segment showed non-linear tensile behavior in the first cycle and residual displacement after unloading. In the following cycles, non-linear tensile behavior was still observed. Incremental displacement was almost same level with that of the cable assembly. The segment tests identified the causes of the non-linear irreversible tensile behavior of the quartz fiber cable assembly under cyclic loading.

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To be used in severe outer space environments, spacecraft may also cause unexpected problems from the ground level. In order to solve the problems, it is important that many of the sliding portions of the spacecraft have been prepared by the lubrication processing. A solid lubricant is suitable in the space environment such as a low pressure and wide temperature changes. Gold film and molybdenum disulfide have been mainly utilized for solid lubricant in spacecraft. These materials have been already examined the tribological characteristics using the variety of additives. Although these lubricants have been applied in the various space environments, tungsten disulfide which has the same crystal structure as molybdenum disulfide has not been studied intensively. In this study, tungsten disulfide has been examined for the application of the solid lubricant in the spacecraft. In order to simulate the deployment friction, the reciprocating tribometer experiments were conducted in a vacuum and air using the aluminum alloy and the stainless steel substrates coated by tungsten disulfide. It was found that the tungsten disulfide lubricant coating have demonstrated the lowest friction coefficient among other solid lubricants. But it also reached its wear life before the end of test duration in a vacuum. To improve the wear life of tungsten disulfide, substrates which coated by mixture of tungsten disulfide powder and polyamideimide have been studied. Comparisons of the two coating methods have been elucidated in conjunction with wear morphology observed by EDS-SEM.

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The Facility for Attitude Control Experiments (FACE) has been implemented at the Institute of Space Systems of German Aerospace Center (DLR) in Bremen, Germany. The facility's objective is testing and verification of the Attitude Determination and Control System (ADCS) under the realistic environment in low Earth orbit. Regarding the evolving ADCS software and hardware, a complete end-to-end verification of ADCS significantly contributes to the mission success. FACE consists of a hemispherical air-bearing with satellite component platform, preliminary solar simulator, and magnetic field simulator. Besides, the implemented automatic center of mass (CoM) calibration software adjusts the CoM of the whole platform and, thus, it can perform minimal friction motions in 3 axes as if in orbit. Furthermore, the platform provides multi-output power distribution system and WLAN command interface. Thus a self-sustaining satellite is arranged on the platform which can be subjected to various tests. A hardware-in-the-loop test using flight components can be performed simply by mounting the desired sensor or actuator onto the platform. In particular, FACE is now prepared for the system verification of DLR's CompactSatellite program. We introduce the real-time test bench with specific devices, their performances, and future extensions in progress.

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This paper describes a case study of a workload and development-time reduction method to enhance the benefits of using small satellites. The method consists of (1) a simplified satellite system design and requirement for attitude determination and control system (ADCS); (2) a simplified fault detection, isolation, and recovery (FDIR) system; and (3) a simplified software design that allows the software architecture to be reused. For the system analyses, this study proposes to select and focus on the most important parameters, especially system or mission survivability. The bus-system safety analysis is related to power generation, and the mission survivability analyses are related to the possibility of solar radiation incidences to the imaging sensor. The control algorithm and proposed system feasibilities are verified by model-based simulation. The results show high survivability of the designed system.

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As the missions and functions of satellites differ, on-board computers used in small satellites are frequently developed individually at the relevant organizations. Although the satellite missions may differ, their complicated software may consist of common functional elements when the software structure is segregated into its functional elements, such as the equipment interfaces, ground communications, and attitude estimation. By recursively using a common software platform for many different satellites, we can expect an improvement in reliability through the mutual utilization of the platform and an increase in productivity from its inter-utilization. Therefore, we have developed a software development framework for the on-board computers used in small satellites. We created this software development framework through the following procedure. First, the basic composition of the on-board software was modularized for each function. The modularized components were then converted into class structures by extracting the similarity of each module. Using class structures, the software can be developed with a reduced amount of coding, and new software modules can be generated easily by simply modifying the code. In addition, the proposed software development framework was created for portability, allowing it to operate on many on-board computers. In this paper, the basic concept of the software development framework and its application to small satellites are described.

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The 2-unit size cubesat RAIKO is a nanosatellite developed by Tohoku University and Wakayama University. This paper shows the mission and system specifications. The satellite was released to space on October 4, 2012 from International Space Station, which was the 419-km alt. circular orbit. The techniques for 50-kg microsatellites by Tohoku University are transferred to this satellite, so a lot of functions are included although the power and mass budgets are strongly restricted. The primary missions are the photo storage by different 3 optical sensors, the de-orbit mechanism experiment by expandable thin films, and Ku-band downlink communication experiment. The satellite operation was finished by orbital decay on August 6, 2013. The telemetry data were successful received in total 123 passes, in which total 63 photo images were obtained and maximum 100 kbps (200 ksps) downlink was successful. Using color CMOS camera, gradually separating ISS could be confirmed. From analysis of house-keeping data, the solar generation power in sunshine was 3.38 W (no paddles) to 5.77 W (with paddles) in average, the temperature of onboard computer was in the range of 20.8 to 28.7 deg C, and the battery temperature was 4.2 deg C in average. The real flight data from the 10-month operation will be precious information for future nanosatellite projects.

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IKAROS (Interplanetary Kite-craft Accelerated by Radiation of the Sun) was injected into the Venus transfer orbit by H-IIA rocket together with AKATSUKI on 21st May 2010. IKAROS has newly developed Reaction Control System called Gas-Liquid Equilibrium thruster. Gas-Liquid Equilibrium thruster loads propellant as liquid state and eject as gas state. Gas-Liquid equilibrium thruster is the thruster system suited for small spacecraft because of its easy handling depending on the non-toxic and non-inflammable propellant, which has relatively low pressure. This paper shows the development and operation result that this new thruster system work on good conditions at interplanetary trajectory compared to the prospect of performance.

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This paper presents a complete design and implementation of a Single Event Upset (SEU) emulation system that can be used to inject faults Static Random Access Memory (SRAM) based Field Programmable Gate Array (FPGA). The FPGA is used to implement an avionics system for a small satellite. The fault injector emulates the expected Single Event Upset (SEU) rate as it would be in the Low Earth Orbit (LEO) of the polar orbiting satellites at inclinations close to 98° deg., and altitude of about 670 km. The emulator injects faults in the configuration bit-stream of the FPGA without stopping its operation. It makes use of the partial reconfiguration feature of today's FPGAs. This provides a facility to assess the design performance in space even if radiation testing will not be conducted before launching. Also, it simulates the expected upset rate and hence calculates the corresponding data failure rates for Triple Modular Redundancy (TMR) fault tolerant designs. The system was implemented using the Xilinx Virtex- LX50T FPGA. The FPGA suffered system failures during the fault injection test. It recovered about 50% of the failures. TMR simulation at an upset rate of 0.1 upsets (per bit per second) for a data size of 2048 bits showed that about 33% of the faults will be fully corrected.

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Images taken from space are used for various purposes such as Earth observations and disaster monitoring. A new use for such images has emerged—personal amusement. Therefore, we consider whole-sky observations around a satellite using a microsatellite, Rapid International Scientific Experiment Satellite (RISESAT). However, extensive amount of equipment must be installed on microsatellites in a limited amount of space. Therefore, the equipment must be very small. We have developed a data-handling unit capable of processing the data received from more than one camera head, as well as from small camera heads with more than one viewpoint. In this way, we can reduce the number of camera heads installed on a microsatellite. We were therefore able to realize a camera system for a microsatellite installation. Satellite equipment must be able to withstand harsh conditions such as vibrations, high vacuum, and severe temperature changes. In this paper, we conducted environmental tests on the proposed system, and herein we report the development and evaluation results.

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The Space Robotics Laboratory of Tohoku University has three 50kg Micro-satellite projects. The first satellite “SPRITE-SAT” has been successfully launched into Earth orbit, and also been operated. The flight model of the second satellite “RISING-2” has been assembled and its software development is now finalized, being ready for the launch planned in the next year. The third satellite “RISESAT” project is during the Engineering Model (EM) development phase at the time of writing. Some micro-satellites can repair its software by batch file on orbit however most of it is not able to repair its basic software and system-configuration after launch. Therefore, it needs to be evaluated about its system that includes software and hardware in detail. The Space Robotics Laboratory (SRL) of Tohoku University aims to establish a verification environment for micro-satellites system through the RISESAT project. SRL named it as MEVIµS: Model-based Environment for Verification and Integration of µ-Satellite. MEVIµS system has some software and hardware. Its software simulates orbit and satellite environment such as solar power, thermal environment, attitude information and operation of equipment. Its hardware establishes interfaces between simulator and equipment of real-satellite. SRL is planning to establish an environment of hardware-in-the-loop-simulation (HILS) for RISESAT by MEVIµS and RISESAT-EM. RISESAT-EM will be evaluated by its HILS system and its software and hardware of equipment will update continuously until flight model development phase. The paper will show detail of MEVIµS configuration and result of application to RISESAT-EM.

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As minaturisation of ever improving enabling technologies increase the capabilities of small satellites, the issue of commercially affordable access to Earth orbit becomes more significant. Whilst the current practice of multiple manifesting is dominant, the emergence of new small launch vehicles may instigate a transition to the dedicated launch of these small satellites. A brief review of the current range of launch vehicles is presented and available small satellite launch market projections briefly examined. The small launch vehicles currently in development are also outlined and their potential to drive the future small satellite launch market discussed.

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The Kyutech (Kyushu Institute of Technology) Satellite Project developed a high-voltage demonstration satellite called “Horyu-II” between 2010 and 2012. Horyu-II is a nanosatellite 350 mm x 310 mm x 315 mm (X*Y*Z) in size, with a mass of only 7.1 kg. This satellite was launched on May 18, 2012 as a piggy-back payload of the 21st H-IIA launch. Its missions are the demonstration of high-voltage technology in orbit, mitigation of electrostatic discharge (ESD), and so on. In this paper, we describe the design of the power system and its verification through various ground tests. The power system is equipped with a thin-film double-junction GaAs solar cell, with an efficiency of 20%, as the primary power source for the first time in orbit. The satellite also carries Ni-MH batteries for power storage. The power system architecture was simplified as much as possible with failure prevention mechanisms, such as over-current protection and various switches related to safety and debris mitigation. We present the analysis of the telemetry data obtained after the launch and validate the effectiveness of the design and verification processes.

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The H-II Transfer Vehicle (HTV) is a Japanese unmanned cargo transfer vehicle developed for the International Space Station (ISS) re-supply and waste disposal purposes. HTV1 through HTV3 completed the mission successfully, and HTV4 through HTV7 are planned to be launched once a year continuously. Under the circumstance that the achievement is evaluated highly and the expectation for the new usage of HTV is increased, we have prepared a new platform and report some experiments plan with using it in the paper.

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This paper describes onboard balance system used in the rocket sled test on the high speed test track. Newly developed acceleration-compensated balance mechanically cancels inertia force and enables us to use suitable size load cells for expected aerodynamic force. Lift force was evaluated by another internal 6-axis balance. With a flat plate and AGARD-B model, system verification tests were conducted to clear the accuracy of this system. Although the cancellation of the onboard G-force was almost accomplished, uncertainty of the wind speed or mechanical friction in the system caused severe error to the measured drag coefficient.

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Japan contributes essential services to space experiments and enables human activities included as part of the international partnership of the ISS program by utilizing the HTVs (Kounotori). As the next step toword on-orbit service, JAXA has commenced technical research into cargo return from orbit. The HTV was used in research as the base design and a return vehicle was added to enhance performance. The combined vehicle is called the "HTV-R". HTV-R enables JAXA to recover various samples of experiments conducted on the ISS and equips a new return vehicle called as "HRV (HTV Return Vehicle)" for the enhanced function. The HRV will fly autonomously and conduct lifting re-entry into the atmosphere by controlling the attitude and trajectory to a predefined splashdown point. Now two types of vehicle concepts are being investigated. One uses an HTV as the base system for orbital flight and minimizes the initial cost of HTV-R program, and the other integrates the HTV components into a new vehicle, optimizing the on-orbit functions to minimize the recurring cost.

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The development of the Epsilon launch vehicle, Japan's next generation solid rocket launcher, has just moved to the final stretch for its first launch scheduled in the summer of 2013 to carry the planetary telescope satellite SPRINT-A. The JAXA appreciates the advantages of combined benefits of the standardized small satellites and the Epsilon's highly efficient launch system in order to increase the level of space activities. The primary purpose of Epsilon is to provide small satellites with a responsive launch that means “Small, Low cost, Fast and Reliable”. The attention should be directed toward the innovative design concept of Epsilon, which aims at developing the next generation technologies such as the highly intelligent autonomous checkout system and the mobile launch control. Now that the full-scale development is about to be finished, the most important is what the next step should be beyond the Epsilon. This paper deals with the significance of the Epsilon launch vehicle and how it contributes to the possible evolution of future space transportation systems.

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Since the launch of the Japanese Experiment Module KIBO in 2008, three crystal growth experiments have been performed. For each experiment, an Experiment Unit (EU) was developed based on the discussion with the Principal Investigator (PI). Using the EU, ground control experiments were conducted before flight. After launch, experiments were run repeatedly to check the reproducibility of the measurements. Experiment coordination process is introduced together with the overview of the experiments.

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Plant growth and development are affected by abiotic factors such as light, temperature, water and gravity. Gravity ensures primary shoot grows upward towards sunlight to optimize photosynthesis, while the primary root grows downward into the soil to find water and mineral supply. Plants with impaired gravity response are poorly fit for survival in nature, since the roots may not be able to absorb the nutrient and the shoot may not be able to track sunlight. In the first study, the tomato seedlings on agar medium were treated on clinostat in light and dark condition. In dark, the tomato seedlings on the clinostat responded by bending their shoot and coiled their root. In the light condition, the shoot bending and root coiling were reduced significantly compare to the plants grew in the dark after seven days in clinorotation, which might indicate that phototropic response was stronger than gravitropic response in tomato seedlings. The mung bean on hanging mesh was tested on clinostat without light. Under this condition, instead of coiling, the root grew staight to the wet rockwool. The condition might indicate that mung bean seedling has stronger hidrotropic response compare to gravitropic response, as moisture gradient may trigger statolith degradation in columella cells.

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Molecular dynamics simulation was performed to investigate unique crystalline states of ionic crystal at condition of a strong gravitational field (one million G). The simulation results showed that lattice vibration spectra of anion and cation along the gravity direction and the normal directions of the gravity were analyzed to confirm crystalline states of the ionic crystal. It is found that the shapes of spectra along the gravity are obviously different from the others along normal directions of the gravity. In addition, the peaks of spectra along the gravity were shifted toward higher frequency. It is shown that anisotropic lattice vibration spectra were induced by strong gravitational field, and it is insisted that the unique crystalline states and physical properties are induced by strong gravitational field.

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The electrostatic levitation furnace is under development for the International Space Station. Since metallic samples can be levitated under terrestrial conditions, the main target in microgravity are oxides, which are difficult to levitate in 1-G. Thermophysical properties such as density, surface tension, and viscosity of molten oxides at high temperature will be measured in the ISS. In this paper, some key techniques necessary for the ISS-ELF are introduced. Also, preparatory works and considerations necessary for ISS experiments are discussed.

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For demonstration of the upgraded microgravity experimental system by the balloon operated vehicle, combustion experiment of fuel droplet array has been prepared. Development of the experimental apparatus is completed and preparation toward execution of the flight experiment in 2013 is proceeding. In this paper, overview of the experiment and the latest status will be explained with emphasis on scientific aspects of combustion research.

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The “Group Combustion” experiment is planned as the first combustion experiment in the KIBO on the ISS. Flame spread characteristics of n-decane droplet clouds and linear array will be investigated in detail. The experiment will employ the Multi-purpose Small Payload Rack (MSPR), the Chamber for Combustion Experiment (CCE), and the Group Combustion Experiment Module (GCEM) as experimental apparatus. At present, development of the GCEM has been on-going in parallel to detail planning of the experiment operation onboard the KIBO. In this paper, current status on preparation of the experiment will be introduced.

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Sounding rockets are suitable platforms to provide the opportunity to carry out research in materials science, fundamental science, and biology. However, no sounding rocket developed in Japan has been served for microgravity experiments after termination of TR-1A rocket launching, while TEXUS and MAXUS rockets are frequently used as platforms for microgravity research in Europe. The present paper briefly describes the following in situ observation experiments under microgravity during free-fall flights of ISAS sounding rockets S-520-24 and S-520-28: (1) faceted cellular array growth, (2) diamond synthesis, (3) nucleation of WO₃ and Fe in gas phase, and (4) nucleation of calcium carbonate. All the experiments were successfully performed in the 7 min microgravity conditions as a result of active control of spin of payloads. In the crystal growth experiments, heat and mass transport process near the crystals were optically visualized and then the kinetics on the growing crystal surface was quantitatively evaluated. In the nucleation experiments, nucleation rate under microgravity was drastically decreased compared with that under the terrestrial condition.

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This work is devoted to propose the concept of the laboratory-scale test facility to provide a partial-g environment based on slope-sliding method, SSMe. SSMe mainly consists of the experimental rack and the less-frictional slope which enable to set at the prescribed angle against the ground. During the sliding operation, the experimental rack should freely “fall-off” in the direction of the sliding so that the normal component of gravity force against the slope surface only remains inside the rack. In this manner, partial-g environment is easily achieved and the target gravity level can be controlled by modifying the slope angle. In this paper, the simple demonstration was performed to verify this methodology works by using the small diffusion flame as the convenient gravity sensor. Several issues including engineering design are discussed in order to address the problems to be managed in future.

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This paper presents the requirement specifications for an output filter for a 21-GHz band broadcasting satellite system and shows simulation results of the characteristics of the filter. The proposed 21-GHz band broadcasting satellite system is applied to a wideband single carrier transmission using bandwidth of approximately 300 MHz and an array-fed reflector antenna for power control to countervail attenuation due to rainfall. The power radiated to the rainy area is boosted intensively by a beam forming network. Therefore, a satellite transponder has multiple output routes, and each route is equipped with an output filter. Considering this system, the output filter was designed for a linear frequency response and low in-band group delay, and sufficient suppression of interference from adjacent bands such as the radio astronomy band. We evaluated the electrical characteristics by computer simulation; low-loss and low-group delay deviation in the satellite broadcasting band and sufficient attenuation in the radio astronomy band were confirmed.

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Satellite broadband transmission signals require reduction in signal distortion to maximize transmitter power source efficiency. This paper proposes and investigates the effects of using a Volterra filter to adaptively compensate for nonlinear amplifier distortion and frequency characteristics in satellite communications. The effectiveness of a Volterra filter was verified by computer simulations. The computer simulations indicated that the bit error rate (BER) characteristics for multilevel modulation are significantly improved. We expect an improvement in transmitter power source efficiency of an earth station of a satellite communication system.

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Flow field and aerodynamic performance of the Mars airplane with a complete aircraft configuration are analyzed by RANS simulations. At the Reynolds number of 3.3x10⁴, a flow field is solved by an unstructured three-dimensional compressible CFD solver (LS-FLOW). Here, the Mars airplane is assumed to have the Ishii airfoil as the main wing shape. The Ishii airfoil is known as its good performance at the low Reynolds number condition. An objective of the present study is to clarify flow structures around a complete aircraft, for optimization of design of the Mars airplane. The results show that the features of the aerodynamic coefficients correspond to those of experimental results and the contribution of the main wing is significant on the aerodynamic characteristics of the entire airplane.

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Enceladus is the only icy satellite known to exhibits on-going geological activity of water-rich plumes derived from the interior ocean. Here, we propose a sample return and in-situ measurement mission for Enceladus' plume materials. Depending on the cost, mission duration, and propulsion system, we propose three types of missions to Enceladus; type 1: free-return trajectory, type 2: trajectory orbiting Saturn, and type 3: trajectory orbiting Enceladus. Type 2 and 3 are preferable to type 1 in order to achieve lower encountering velocity to the plumes (> 4 km/s and 0.2 km/s for type 2 and 3, respectively) and, thus, to collect multiple and intact samples. High resolution mass spectroscopy of the gas components will provide essential information to understand the physical and chemical conditions of both the interior ocean and the solar nebula. Furthermore, detailed onboard and onshore analyses of returned samples could provide geochemical, preboplogical, and, potentially, biological context in the interior ocean of Enceladus.

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A flow condition on the wing of Mars airplane becomes low Reynolds number (10⁴ to 10⁵) for a reason of low atmospheric density on the Mars. However an effect of a propeller slipstream for the wing at low Reynolds number is not clear. We measured aerodynamic force on three types of airfoil with/without the propeller, and visualized flow field on the wing surface. From the results of force measurement, aerodynamic characteristics of the flat plate was almost unaffected by propeller stream. However aerodynamic characteristics of the Ishii airfoil and NACA0012 were changed by propeller slipstream. To see the results of visualization, the flow separation was prevented by the effect of propeller slipstream. These results caused the changes in aerodynamic characteristics.

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This paper presents the extended missions of the IKAROS solar sail interplanetary spacecraft. IKAROS entered an extended operation phase at the beginning of 2011. During this phase, its spin rate was reduced to observe deformation of the sail membrane under low centrifugal forces, and on Oct. 18, 2011 the spin was reversed to enhance knowledge of the membrane’s stiffness against solar radiation pressure. We also investigated changes in IKAROS’s attitude motions under reverse spin conditions. At the end of 2011, IKAROS switched to hibernation mode due to an increased Sun angle reducing on-board electricity generation. We later searched for IKAROS considering its attitude and orbital motion during hibernation, and on Sep. 6, 2012, we succeeded in locating the spacecraft, which came out of hibernation.A solar power sail can be part of a hybrid propulsion system, with electrical power generated by thin-film solar cells on a solar sail membrane being used to operate ultra-high specific impulse ion engines. This paper also introduces a follow-on mission to IKAROS, a round trip to the Trojan asteroid using hybrid electric photon propulsion.

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Solar Orbiter mission will study the Sun to the proximity of 0.28 AU, reaching solar latitudes up to 34°. This spacecraft will be launched in 2017 and will represent a complete approach to heliophysics. The Polarimetric and Helioseismic Imager (PHI), on board of Solar Orbiter, will provide the most important data for helioseismology. PHI will measure the photospheric vector magnetic field and the line-of-sight velocity observing the FeI 6173 Å absorption line with a narrowband filtergraph (FG). At different spectral positions, the polarization state of the incoming light will be analyzed. The FG will provide a tuning range to compensate the spacecraft radial velocity and to scan the continuum at both sides of the absorption line. Thus, the fine tuning of the FG is essential for the instrument performance. Here we present the FG characterization and calibration status as they represent an important milestone in the development of the instrument.

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Hayabusa2 mission has started as the follow-on mission of Hayabusa. The target asteroid is 1999 JU3, which is a C-type asteroid. The scientific purpose is to study the formation and evolution of the solar system, especially to study the organic matter and water, which existed in the early stage of the solar system formation. The engineering is also important and the spacecraft will be much more robust and reliable with some new technological challenges. The launch of Hayabusa2 is planned at the end of 2014, arriving at the asteroid in the middle of 2018, and it comes back to the earth at the end of 2020. At present, the flight model is under manufacturing.

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Aerodynamic characteristics and flow fields around an owl-like airfoil at a chord Reynolds number of 23,000 are investigated using two-dimensional laminar flow computations. Computed results demonstrate that the deeply concaved lower surface of the owl-like airfoil contributes to lift augmenting, and both a round leading edge and a flat upper surface lead to lift enhancement and drag reduction due to the suction peak and the presence of the thin laminar separation bubble near the leading edge. Subsequently, the owl-like airfoil has higher lift-to-drag ratio than the high lift-to-drag Ishii airfoil at low Reynolds number. However, when the minimum drag is presented, the Ishii airfoil gains lift coefficient of zero while lift coefficient of the owl-like airfoil does not becomes zero. Furthermore, a feature of unsteady flow structures around the owl-like airfoil at the maximum lift-to-drag ratio condition is highlighted.

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Our project aims to search for methane-oxidizing microbes on the Mars surface. The project is in preparation under the scheme of the MELOS working group. Martian soil will be sampled from a depth of about 5 - 10 cm below the surface, where organisms are expected to be protected from the harsh hyper-oxidative environment of the Mars surface. The soils will be stained with a cocktail of fluorescent reagents, and examined by fluorescence microscopy. A combination of fluorescent dyes has been selected to identify life forms in samples. A combination of dyes will be used to detect membranes surrounding the “cell”. A substrate dye that emits fluorescence upon cleavage by a catalytic reaction will be used to detect the catalytic activity of the “cell”. This combination will also be useful for detecting pre-biotic organic material as well as remnants of ancient Martian life. Hydrolysis of the polymers in the “cell” followed by HPLC for amino acid analysis will be effective for examining whether Martian life is identical to or different from terrestrial life. The number and type of the amino acids as well as their chirality will be analyzed to distinguish whether the polymers are contaminants from Earth.

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Tanpopo, a dandelion in Japanese, is a plant species whose seeds with floss are spread by wind. We propose this mission to examine possible interplanetary migration of microbes, and organic compounds at the Exposure Facility of Japan Experimental Module (JEM: KIBO) of the International Space Station (ISS). The Tanpopo mission consists of six subthemes: Capture of microbes in space (Subtheme 1), exposure of microbes in space (Subtheme 2), analysis of organic compounds in interplanetary dust (Subtheme 3), exposure of organic compounds in space (Subtheme 4), measurement of space debris at the ISS orbit (Subtheme 5), and evaluation of ultra low-density aerogel developed for the Tanpopo mission (Subtheme 6). “Sample Trays” for exposure of microbes and organic materials and “Sample Aerogel Panels” for aerogel will be launched. The trays and panels will be placed on the Exposed Experiment Handrail Attachment Mechanism (ExHAM) in the ISS. The ExHAM with trays and panels will be placed on the Exposure Facility of KIBO (JEM) with the Japanese robotic arms through the airlock of KIBO. The trays and panels will be exposed for more than one year and will be retrieved and returned to the ground for the analyses.

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Future space missions are expected to use space robots that will support or replace astronauts to prevent them from having to carry out dangerous operations. One of the most important issues for such astronaut support robots is locomotion technology. Locomotion mechanisms require a long reach, lightweight materials, and robustness. JAXA has developed a novel locomotion system that has a long reach and is lightweight and robust. The system uses an extendable robot arm and several tethers. By controlling the length of the tethers, the robot can move within a triangular plane as defined by the anchor points of the tethers. The anchor point can be replaced by an extendable robot arm using a STEM (storable tubular extendible member) mechanism. The SRA (STEM robot arm) is lightweight and has a compact housing and long reach. However, it is also flexible, and this causes control difficulty. The REX-J [robot experiment on JEM (Japan experiment module)] demonstration mission was conducted at the International Space Station between August 2012 and May 2013. In the experiment, the vibrations of the SRA and tether system under various triggers were measured by a vision system. In this paper, the flexibility and vibration characteristics of the SRA of the REX-J robot in the space environment are analyzed based on the flight data, and their effects on the control of the robot and the utility of the system are evaluated.

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A fully reusable sounding rocket is proposed in JAXA/ISAS to provide frequent opportunities for atmospheric observation mission with low cost and with short turnaround time, and also to improve technology readiness levels for reusable space transportation systems. This rocket will take off vertically, reach to the high altitude more than 100 km, land on the launch site vertically, and be launched again within 24 hours. The main propulsion system is clustered LOX/LH2 engines with full-time abort capability in spite of the one engine fail. In order to realize the reusable sounding rocket, the main propulsion system should have advanced features of high reliability, reusability, maintainability, and survivability. To fulfill those requirements, followings have been considered and reflected in the engine system design, i.e., optimization of design margins among components for high reliability and reusability, deep throttling capability for vertical landing, and health monitoring capability for abort operation, easy inspection and maintenance for short turnaround time. Those functions and performance are going to be verified and demonstrated through ground engineering tests at Kakuda Space Center/JAXA in 2014. This paper shows the design considerations, the engine system and major components design, and the current status and plan of technology demonstration tests.

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Clouds have an important influence on Earth's water and energy balances, and cloud-related processes underpin key climate feedbacks. However, fundamental scientific understanding of water cloud forcing and feedbacks still remains one of the largest sources of uncertainty in climate sensitivity estimates. Cloud remote sensing from spaceborne sensors has been providing useful information for reducing such uncertainties in climate studies. Cloud droplet effective radius (CDER) and cloud optical thickness (COT) of water clouds are important observables obtained from remote sensing that characterize cloud droplet size distributions. Moreover they are indicators of the droplet growth such as condensational growth and collection processes. CDER and COT can be obtained from solar-reflected measurements by passive multispectral imagers such as Aqua/MODIS, EarthCARE/MSI, and GCOM-C/SGLI. However, interpretation of the obtained CDERs in terms of cloud structure and droplet growth is complex because clouds are typically inhomogeneous both vertically and horizontally. In this study, we discuss recent progress in interpreting CDERs obtained from satellites in terms of vertical and horizontal inhomogeneities by using numerical cloud models, high spatial resolution measurements, and active instruments. We first investigate the impact of in-cloud vertical structure and sub-pixel horizontal inhomogeneity upon obtained CDER by using a numerical cloud model and remote sensing simulators. Second, we introduce a research strategy for quantifying the effect of sub-pixel horizontal inhomogeneity by using high spatial resolution measurements from Terra/ASTER. Finally, we show a relationship between obtained CDER and droplet growth in nature based on combined use of spaceborne active and passive sensors (CloudSat and Aqua/MODIS).

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A conceptual study was undertaken on earth observation missions for a satellite within the Sun-Synchronous and Medium Earth Orbit (SS-MEO). Our mission study of a MEO Satellite was performed as pioneering research into a newly utilized earth orbit that exists between the Low Earth Orbit (LEO) and the Geostationary Earth Orbit (GEO). One of the advantages of the MEO is that it delivers a wider field of view (FOV), which permits more frequent observations that are more easily obtained, in comparison with the LEO. Another advantage is that the performance demands for sensors are moderate, relative to those for the GEO. This conceptual study of earth observation missions is considered for the baseline (4184 km) orbits, focusing on optical sensors. We summarize the needs of each assumed user (products, observational frequency, and spatial resolution) related to four missions (agricultural, forest, ocean, and air pollution observations). Agricultural observation is expected to need a spatial resolution of 10 m and an observational frequency of a few times a week. As a result, required optical sensor is that with an aperture diameter of 30 cm, an f-number of 11, and a signal-to-noise ratio (S/N) of 20. It is thought that the optical sensor for the agricultural observation would be larger in comparison with the previous optical sensors used within the LEO, because the S/N and FOV are smaller. However, it was found there is a challenge to be met in terms of a compatibility with the f-number and FOV. This paper shows the results of this conceptual study and the issues raised relating to mission sensors for earth observation missions in the MEO.

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The objective of the present study is to apply satellite images (PALSAR) to obtain frequent and accurate coastline data in the Meghna Estuary area of Bangladesh and also utilize the high resolution images to investigate some of the hydro-morphological features of the estuary. Bathymetry of the Meghna Estuary was obtained from the GEBCO 30” free source data. This data was refined by incorporating the recent coastlines through the digitized PALSAR images. It was observed that in satellite images, tidal flats appear as dark patches adjacent to the land areas during the low tides. To compute some of the hydrodynamic features of the Meghna Estuary a 2D hydrodynamic model was set-up. The model was validated through comparison of predicted and observed tidal water levels during 1997 and 2012. The validation includes processes of bathymetry modification by observed data and coastline refinement by satellite images. Simulated stream lines in the computation domain with updated coastlines, show reasonable agreement with certain flow patterns observed in the satellite images. Present monitoring and simulation techniques may be implemented as a strong tool to capture the coastal morphology change especially where one expects shortage of measured data in conjunction with highly dynamic morphology changes.

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This paper examines the use of the spaceborne radar and imagers aboard CloudSat, Aqua, EarthCARE, GCOM-C, and third-generation geostationary satellites for investigating and revealing the cloud evolution processes for warm water clouds. These satellites either have been in orbit or are planned to be launched in the mid-2010s, and will contribute to observations of aerosols and clouds on Earth. Although most data analyses are performed using each satellite and sensor separately, combining the sensors offers the potential of new findings on the states and evolution processes of clouds, such as by obtaining a rough sketch of cloud vertical structure through the use of a microwave scanner and a visible-to-infrared imager, or by observing the cloud evolution transition through the use of a cloud profiling radar and a visible-to-infrared imager. This is the work we aim to perform over the next decade. This research will be conducted by using various kinds of satellites and sensors, radiative transfer theory, electromagnetic scattering theory, and modeling. This paper presents recent topics and strategies for synergistic use of spaceborne sensors with a review of important past studies.

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The next generation Earth and Atmospheric Observation satellites, such as BIOMASS, CoReH2O, PREMIER and METOP-SG, demands sensors with higher resolution and sensitivity, resulting in higher data volumes generated by the sensors, while the downlink capacity of the modern spacecraft does not increase with the same pace. A solution to this challenge is to perform more data compression or processing on-board the satellite. In this contribution, we will introduce a data processing board, coined On-board Payload Data Processing (OPDP), which could enable such onboard processing, especially for SAR and spectrometers. We will describe how data from this type of sensors could be processed by OPDP.

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Western Cambodia is the most productive granary in the country. Since most agricultural lands are rainfed and most farmers rely only on their (non-science-based) experience, they would not adjust to changing rainfall. The Ministry of Water Resources and Meteorology of Cambodia has been working with The University of Tokyo and the Japan Aerospace Exploration Agency under the Space Application For Environment (SAFE) project since May 2012. First, we selected the most reliable general circulation models (GCMs). This was done by comparing with Global Precipitation Climatology Project datasets, which are globally produced with data from rain gauges and satellite. Next, future precipitation data were input to the coupled model of hydrology and crop science. For past simulation, we derived soil moisture from Advanced Land Observing Satellite (ALOS) / Phased Array type L-band Synthetic Aperture Radar (PALSAR). For both past and future simulations, land use was from ALOS/PALSAR and hydraulic conductivity from The University of Tokyo Land Data Assimilation System, which uses Aqua Advanced Microwave Scanning Radiometer for Earth Observing System data as reference. Then, we attained the hydrological condition, optimized planting date, and yield for the future. Finally, we discuss water and food security in Cambodia under the globally changing climate.

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In Cambodia, a hydro-meteorological observation network was not fully re-instated following the civil war in the 1970s. Thus, there is a lack of ground truth data for calibrating satellite precipitation products. To improve this, in September 2009, 16 new rain gauges were installed around Tonle Sap Lake basin, adding to the 19 rain gauges already there. The year was classified into four seasons: “pre-monsoon”, “full-monsoon”, “post-monsoon”, and “dry” by referencing the zonal wind at 700 and 850 hPa. Then, the seasonally accumulated rainfall and its seasonally averaged diurnal distribution were compared with satellite products (TRMM/3B42 and GSMaP) and rain gauge data. The difference between the satellite products and rain gauge data was largest during the post-monsoon season. Rain gauge values were smaller than satellite product values in northern parts, but much larger than the satellite product values in the south. Reasons for the misdetection of rainfall by the satellite over southern parts were examined. We focused on cloud-top temperature during rainfall events by investigating the brightness temperature observed by the MTSAT infrared channel 1. This revealed that the cloud-top temperature was more than 273 K, even during rainfall events, which suggests that it is linked to a unique rainfall mechanism.

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Extreme Ultraviolet Imagers (EUVIs) are the parts of the IMAP (Ionosphere, Mesosphere, upper Atmosphere, and Plasmasphere mapping) mission that aims to elucidate the physical mechanisms in the boundary region between the Earth system and the outer space. In order to reveal the energy transport process in the upper atmosphere, EUVIs direct towards the Earth’s limb and observe helium ions and oxygen ions in the ionosphere and plasmasphere. The EUVIs consist of two normal-incidence telescopes. One telescope detects resonantly-scattered emission from helium ion at the wavelength of 30.4 nm and the other detects oxygen ion emission at 83.4 nm. The primary mirror employs Al/Y₂O₃ multilayer coating technique. The detector consists of a 5-stage microchannel plate assembly and a resistive anode encoder. A metallic thin filter is installed in front of the detector to exclude the bright geocoronal emission at 121.6 nm. Each telescope has a field of view of 13.2 degrees, a spatial resolution of 0.1 degree and a time resolution of 1minute. EUVIs were successfully launched in July 2012 and are now providing images of the plasma distribution in the ionosphere and plasmasphere.

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The “Space Seeds for Asian Future (SSAF)” program is one of the activities of the “Kibo-ABC” initiative under the Asia-Pacific Regional Space Agency Forum (APRSAF). The program intends to promote understanding, and to give regional space agencies experience in the utilization of the Japanese Experiment Module, “Kibo”, of the International Space Station (ISS). It also aims to provide young people in the Asia-Pacific region with opportunities to learn about leading edge sciences through their participations in experiments under peculiar space conditions, including microgravity. Students from Indonesia, Malaysia, Thailand and Vietnam participated in the SSAF2010-2011 program. As part of this program seeds from each of these nations were flown to the ISS and kept in the Kibo Module. These seeds were then returned to Earth where they were germinated and compared to control seed not flown in space. This experiment involved researchers, students and the general public. In the SSAF2013 program, there are plans to cultivate seeds indigenous to Asia in the Kibo/ISS facilities. The plan is to send Azuki bean (Vigna angularis) to Kibo, and observe the growth of their seedlings under dark conditions. Members of the Kibo-ABC initiative are collaborating in the preparation of the seed germination testing procedures, following which many people, including children, students and researchers, are expected to participate in the program.

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Occurrences of dental/oral diseases have been reported in the space environment and pre- or post-spaceflight and the deteriorations of oral defensive functions are evident in the space environment simulated experiments. NASA has identified 6 dental problems (Abscess, Avulsion/Tooth Loss, Caries, Crown Replacement, Exposed Pulp/Pulpitis and Filling Replacement) as the most important dental incidents to be dealt with in the long-term mission. To focus on the dental/oral health management for astronauts, dental examination and dental orthopantomogram are conducted as dental diagnosis. In addition, dental nerve block, dental prosthesis replacement and dental pain control are described in the treatment manual on the International Space Station (ISS). However, the systematic program to evaluate the risk of dental/oral problems in spacecraft and the manual to prevent the dental/oral problems in the space environment are still far from sufficient. To promote the dental/oral health of astronauts, the authors are going to launch “Space Oral Health Promotion (SOHP) project” which will tackle the research tasks and the operational countermeasures in space dentistry.

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On the ISS, some areas do not satisfy the regulation criteria for acoustic noise. Controlling noise is important not only for protecting the hearing of the astronauts who stay on the ISS but also for the human factor, namely the quality of communication. The causes of noise is derived from atmospheric dust in the ISS. One of the main sources of this dust is the daily inboard clothing worn by the astronauts. The reduction of the dust from the inboard clothing is the most important to control the noise.In general, techniques have been developed to reduce dust when processing materials such as thread and fabric. At this time, we considered a technical process to reduce fuzz on 100% cotton inboard clothing used on the ISS, and have developed a clothes model and a singeing machine which can burn and remove fuzz on the surface of three dimensional inboard clothing of various shapes. Furthermore, to evaluate process performance, the industrial standard cellophane tape method was used for fuzz occurring on the surface of the processed samples.

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