This paper presents the attempt to apply UAV (Unmanned Aerial Vehicle) technology to microgravity experiments. The 6-degree of freedom simulation model of an electric-motor-driven test-bed UAV of which span and weight are 2.4m and 2.5kg respectively is established, and the feasibility of microgravity flight is examined using the simulation model and two types of acceleration feedback systems, i.e., acceleration component feedback in body axes and wind axes. The simulation results show that less than 0.15G environment can be reached for more than several seconds, and the quality of the G-level and the duration differs depending on the type of the feedback. The flight testing system has been also developed including the onboard control system, data communication system, and the ground station together with the test-bed vehicle. Flight tests using the acceleration component feedback in body axes are performed, and one the results shows that minimum G-level reached approximately 0.15G as implied by the simulation though the adjustment of the control gains was not enough. This G-level may not be satisfactory for practical use at the moment, but the feasibility of the microgravity flight using UAVs is confirmed by the flight data.
Japanese laboratory (JEM: Japan Experiment Module) in the international space station (ISS), ``Kibo'', was launched and assembled to ISS in June 2008, and full-scale experiments have been started in November 2008. In order to create fruitful scientific results using ``Kibo'', three science fields that are ``Space Genome Science'', ``Space Behavioral Science'', and ``Space Environmental Science'' have been set in JAXA, and three research area that are ``Gravity sensing and response in life'', ``Analysis of biological effects of cosmic radiation'', and ``Environmental adaptation and utilization of space'' have been promoted. The first stage of utilization of ``Kibo'' has been now implemented the experiments of ``Space Genome Science'' that focus to analyze biological molecules such as genes and proteins from the cellular level, and at the present time, December 2009, six experiments selected internationally have been already conducted in ISS. This paper will present 4 experiments. Two of them are plant physiology experiment that have been operated in European Space Agency (ESA) experiment module ``Columbus'' using a European Modular Cultivation System (EMCS), and two experiments of the rest are space radiation biology experiments using a Cell Biology Experiment Facility (CBEF) in ``Kibo''.
Two crystal growth experiments were performed on the Japanese Experiment Module ``KIBO''. The development of the experiment cell, test runs before launch, launch site operation and the actual experiment operation is explained.
Microgravity experiments on the morphological instability and pattern formation of ice crystals growing in supercooled bulk heavy water were carried out in the Japanese Experiment Module ``KIBO'' of the International Space Station (ISS) in the period from December 2008 to March 2009. Totally 134 experiments were successfully repeated in the space and the processes of ice crystal growth were recorded using the interference microscopes with crossed optical axes. Ice crystal growth was observed as a function of supercooling between 0.01K and 2K. The results of these space experiments are introduced very briefly in this report.
FACET, which has been conducted onboard ``Kibo'' since April 9, 2009, was completed on June 12, 2009. FACET aimed to clarify the mechanism of a faceted cellular array growth by precisely observing the phenomena at the solid / liquid interface. Phenyl salicylate / t-butanol alloy was used as a sample material instead of semiconductors or oxides. The crystal growth processes were visualized in situ using a microscope and an interferometer, especially focusing on changes in temperature and concentration in the sample. Some experimental results were briefly reported in the present paper.
As the space experiment design adjustment for the 1st selected theme using Solution Crystallization Observation Facility (SCOF) on board the JEM-KIBO, the ground experiments in order to develop the experiment equipment and cell has been carried out.
The crystal growth experiment was conducted as scientific experiments of the first stage for ``KIBO''. These experiments were ``Ice Crystal'' and ``Facet'' with Solution Crystallization Observation Facility (SCOF). The main purpose of the experiment preparation is the verification of the experiment parameter, the operation procedure, and the resource requirement by use of the ground model that simulates the function of the flight model.