Administrative reform of Japanese Space Policy Structures in 2012

In Japan, there are several government ministries and agencies with important roles in the development and use of space. In 2012, Japan restructured its administrative organs related to the development and use of space through legal amendments to the original acts that established these organs. Although this was an important administrative reform that took four years of planning and discussion to accomplish, this restructuring has not been communicated well outside of Japan. This study provides the first comprehensive overview of the recent legal changes in Japanese space policy. In contrast to some reports, the Ministry of Education, Culture, Sports, Science and Technology (MEXT) still has primary responsibility for the finances and personnel of the Japan Aerospace Exploration Agency (JAXA). This continues to be true even after the Cabinet Office begins its new role as the focal point for formulating Japanese space policy. It remains to be seen how the policy direction of the Cabinet Office will interact with the operational, financial, and personnel responsibilities of MEXT. I argue that knowledge of the roles of MEXT and the Cabinet Office in space policy, and the tension between the two organizations, is key to understanding Japan's future space policy decision-making process. By tracing the history of Japanese space policy since 2001, I also suggest that if bureaucrats had thought more deeply before making major reforms to space policy and its administration, there would have been less confusion over the development of national space policy this past decade. This paper concludes by identifying some key elements to monitor in the coming years of Japan's space policy.     

MPD arcjet system performance test

A new MPD (magnetoplasmadynamic) arcjet system was developed and tested to demonstrate its technological readiness for flight model design. The MPD arcjet, of quasisteady type, was repetitively operated. In the endurance test, more than 10⁵ shots were cleared in continuous operation. Some components cleared more than 10⁶ shots. Cathode erosion was markedly reduced through the use of newly developed material. Thermal data were obtained which define the thermal interface between the spacecraft and the MPD arcjet system. Waste heat from the electrodes was found to be 20–30% of the input power and to vary with repetition frequency. No technological difficulties are foreseen for further continuation of repetitive operation.     

Magnetic resonance image enhancement using V-filter

A method for enhancing the boundaries of magnetic resonance images (MRIs) using a V-filter (a spatial nonlinear filter) is presented. By iterated V-filtering the signal-to-noise ratio of the MRI can be increased while preserving edge sharpness. A simulation experiment was carried out to evaluate the filter, using clinical brain images. The boundaries of the brain tumor and edematous region were precisely extracted by the region segmentation techniques     

Ground-based millimeter-wave observations of water vapor emission (183 GHz) at Atacama,Chile

We report the first results of ground-based millimeter-wave measurements of 183 GHz atmospheric water vapor spectra from Atacama highland (4800 m alt.), Chile. The measurements were carried out in December 2005 by using a spectroscopic radiometer equipped with a superconductive heterodyne receiver. A conspicuous H₂O spectrum at 183 GHz was detected with an integration time of only 1.5 min, and this is the first high frequency-resolution H₂O spectrum at 183 GHz obtained in the southern subtropical region. The vertical profile of H₂O volume mixing ratio between 40 and 64 km were retrieved from the spectrum by using the modified optimal estimation method.     

Study on variable-shape supersonic inlets and missiles with MRD device

This paper proposes a new aerodynamic device, which was designated multi-row-disk (MRD). This device has a cone and stabilizer disks being arranged in the axial direction. This device can arbitrarily change its aerodynamic characteristics by translating stabilizer disks. In the first part of this paper, the effect of several nose shape configurations including the MRD device on the aerodynamic characteristics is reported. By increasing the number of stabilizer disks, zero-lift drag and induced drag can be reduced. It was also found that putting cavities on the conical surface is effective for improving longitudinal static stability. In the second part, the effect of cavity flow instability on pressure and strain oscillation is reported. We drew the design criterion that the configuration of stabilizer disks should be determined not to couple the 1st mode with pressure oscillation frequency, which can be predicted with Rossiter's formula.     

Tolerance of anhydrobiotic eggs of the Tardigrade Ramazzottius varieornatus to extreme environments

Tardigrades are tiny (less than 1?mm in length) invertebrate animals that have the potential to survive travel to other planets because of their tolerance to extreme environmental conditions by means of a dry ametabolic state called anhydrobiosis. While the tolerance of adult tardigrades to extreme environments has been reported, there are few reports on the tolerance of their eggs. We examined the ability of hydrated and anhydrobiotic eggs of the tardigrade Ramazzottius varieornatus to hatch after exposure to ionizing irradiation (helium ions), extremely low and high temperatures, and high vacuum. We previously reported that there was a similar pattern of tolerance against ionizing radiation between hydrated and anhydrobiotic adults. In contrast, anhydrobiotic eggs (50% lethal dose; 1690 Gy) were substantially more radioresistant than hydrated ones (50% lethal dose; 509 Gy). Anhydrobiotic eggs also have a broader temperature resistance compared with hydrated ones. Over 70% of the anhydrobiotic eggs treated at either -196°C or +50°C hatched successfully, but all the hydrated eggs failed to hatch. After exposure to high-vacuum conditions (5.3×10(-4) Pa to 6.2×10(-5) Pa), the hatchability of the anhydrobiotic eggs was comparable to that of untreated control eggs.     

FPGA-based operational concept and payload data processing for the Flying Laptop satellite

Flying Laptop is the first small satellite developed by the Institute of Space Systems at the Universität Stuttgart. It is a test bed for an on-board computer with a reconfigurable, redundant and self-controlling high computational ability based on the field programmable gate arrays (FPGAs). This Technical Note presents the operational concept and the on-board payload data processing of the satellite. The designed operational concept of Flying Laptop enables the achievement of mission goals such as technical demonstration, scientific Earth observation, and the payload data processing methods. All these capabilities expand its scientific usage and enable new possibilities for real-time applications. Its hierarchical architecture of the operational modes of subsystems and modules are developed in a state-machine diagram and tested by means of MathWorks Simulink-/Stateflow Toolbox. Furthermore, the concept of the on-board payload data processing and its implementation and possible applications are described.     

Two-dimensional Marangoni and buoyancy convection related to crystal growth techniques in space

The natural convection in the horizontal liquid layer driven both by surface tension gradient and buoyancy was investigated experimentally and theoretically.The fluid motion was visualized by mixing fine flakes of aluminum into the liquid. At the same time, the temperature field was visualized by the Mach-Zehnder interferometry and the local temperature gradient distributions were visualized by making use of the refraction of parallel incident light.The numerical analysis using the Galerkin method was also carried out which agreed well with the experimental results.It was found that the velocity and temperature fields of Marangoni convection were varied depending on the aspect ratio of the liquid layer and on the coupled buoyancy convection.