As microgravity experiments using the aircraft, Japan Space Forum has offered the microgravity experiments opportunity since 1997 in the management of -space-related ground-based research activities- contracted to the National Space Development Agency. As the feature of microgravity experiments using aircraft 〇Micro-gravity environment below 10－2 G can be maintained for the longer time than the drop shaft by parabolic flight. (For about 20 seconds) 〇Repeated experiments are possible. (Eight-ten parabolic conditions can be obtained by one flight) 〇The investigator can operate and observe during ｆｌight experiments. For planning the experiment using aircraft, different planning from other facilities is required. The experiment to make the most use of the advantage peculiar to this facility is also required. Moreover, when harnessing these features in the maximum, We ask the investigators following consideration: (a) Safety The safety check of the experiment equipment and samples carried into the aircraft. (b) Intensity of experiment equipment The intensity check of the experiment equipment that bears the too heavy gravity acceleration generated before parabolic flights and after. Now, the ground-based research activities on space utilization, International Announcement of Opportunity, etc. are also performed. Importance of microgravity experiments using the aircraft and the drop shaft facility has increased as preliminary experiments. We expect the research theme through the ground-based research activities will be developed to the theme using -kibo-, and the interest of investigators towards space utilization will increase in future.

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The reduced-gravity aircraft experiment (show following as Aircraft Experiment) has been carried out really since 1990 in Japan and now around 1000 parabolic flights have been performed yearly. And around 90% of Aircraft Experiment have been carried out with the fund of -General Recruited Ground Experiment Theme- (Koubo Chijyou kenkyuu) by NASDA via JSF. In the contact system for-Koubo Chijyou kenkyuu-, JSF contracts Diamond Air Service Inc. (DAS) and scientist each other under NASDA, and another type experiment is contracted between DAS and scientist directly. This paper introduce typical application procedure the for mainly not -Koubo Chijyou kenkyuu-. And each technical requirement for aircraft experiment will be referred to next paper -Outline and Notes about Reduced-gravity Experiment by Airplane-.

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Since 1990, Reduced-gravity experiment flight has been carried out about 8000 parabolic flights by Mitsubishi MU- 300 and Gulfstream-II airplane in Japan. Reduced-gravity experiment flight by airplane has various features in comparison with in space experiment, besides the easy operation way further more in following point. 1. It can perform many experiment times. 2. Scientist can go through the reduced-gravity conditions. 3. Scientist can watch the actual indications in hand and can change the condition settings and controlling timing, etc. 4. Airplane can set various gravity level ( +0.03-2.5 G) with scientist needs. And this paper introduces the outline of airplane experiment, design and fabrication of experiment system, notes for good result, safety and mentioning experienced accident too.

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Since 1996, Reduced-gravity experiment flight by Gulfstream-II (G-II) airplane has been carried out for the large sized or more electric power system experiment. For the life science or medical area scientist requirement, Diamond Air Service Inc. has been studied to modify the interior of G-II cabin for -Free Space Style- and the modification plan was approved by Civil Aviation Bureau of Japan this time. Up to this time, scientists and subjects need to fasten their seatbelt during the reduced-gravity experiment flight in Japan; notwithstanding they are conducting the free space training or ex­periment with unfastened condition in U.S.A., Russia, and France. This paper introduces outline of modified G-II airplane in hard and soft area for ''Free Space Style'' specification. And it will assure the good free space environment for manned reduced-gravity experiment flight training and medical or life science conditions such as standing, sitting, and reclining positions or free floating condition.

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We have performed the reduced-gravity experiments on fluid and thermal phenomena by airplane since 996. They were concerned with -subcooled boiling of wate, thermocapillary flow in liquid film- and -natural ocnvection. Through these reduced-gravity experiments, we obtained some informations that were expected to be very useful for the next experiments. In this article, some notes are presented for the design and the manufacturing of experimental system and the working in the hangar. Then, the brief information on airplane operations is introduced for the pleasure of flight experiments.

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Microgravity experiments on colloidal self organization are described especially for the colloidal crystallization kinetics, rotational diffusion and synthesis of colloidal particles. A gravitational field is one of the important parameters for the physico-chemical properties of colloidal dispersion systems. This overview introduces the large microgravity effects on the colloidal systems, such that ) colloidal crystallization is retarded, ) crystallization for the colloidal alloy systems is enhanced, 3) accurate determination of the rotational diffusion constants is available, 4) vesicles are formed from the polycondensation of ylon, and 5) formation reaction of colloidal silica spheres is retarded.

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The present report briefly introduces recent parabolic flight experiments on high-pressure droplet combustion. Dependence of burning characteristics of single fuel droplets both on ambient pressure and on gravitational acceleration was examined. Ignition delay of 1-octadecanol droplets had a minimum at an ambient pressure near to the critical pressure of the fuel. The ignition delay was not affected by residual reduced gravity. Burning rate constant of methanol droplets increased monotonically with increasing ambient pressure. Residual gravitational acceleration of the order of 10- 2 G induced an appreciable influence on the burning rate constant. Variation of burning rate constant as Gr1/4 was confirmed experimentally by varying gravitational acceleration and ambient pressure.

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Critical problems are in an airplane experiment the timing control of operating sequence and one-to-one communication between the pilot and experimenter. To manage the two problems is a key to succeed the experiment. This story nar­rates episodes of the author's micro-G experiences, which may indicate useful know-how and skills for peoples who are to conduct airplane experiments.

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Crystallization studies on InGaSb have been done under reduced gravity (10- 2 G) condition using an airplane and normal gravity (1 G) condition. The resultant InGaSb crystals were found to contain many needle crystals in both the cases. However, in the case of the InGaSb crystal prepared in the reduced gravity condition, more number oflarge sized needle crystals were present than in the sample prepared under normal gravity. This may be due to the reason that the heat transfers under the reduced gravity condition are restricted to some extent as the convective forces are less active than those under the normal gravity.

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Experience in human experiments with aircraft-parabolic flight is still being accumulated in Japan since the first flight of January 28, 1986; it was the day that the miserable mishap of Challenger occurred in the previous night. A short micro-G phase of 20 sec in parabolic flight is absolutely a limiting factor for human study; the researches made are mostly neuro-vestibular and space perception/orientation and less frequently cardiovascular and hormonal. In these studies, possible effects of preceding hyper-G must be a problem to be cautioned. A tight restraint of subject's body is sometimes necessary for neuro-vestibular study, and several types of electric noises during the flight can be troublesome in elec­trophysiology. Mental uneasiness and strain are common to subjects naive to parabolic flights, and motion sickness symptoms are not infrequent during the flight. Future activities using parabolic flights, in our country, may involve screening of space-crew selection and/or training for space-motion-sickness. Moreover, an experience of parabolic flight may be placed as a preflight routine in the upcoming space tourism.

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A ground-based electrostatic levitation furnace (NASDA-ELF) has been developed by the National Space Development Agency of Japan (NASDA). This furnace can levitate and melt a around 1-3 mm diameter sample in containerless conditions. It has been developed not only as a test model for flight hardware on-board the International Space Station (ISS), but also as a tool for metastable phase research on the ground. This paper describes its design, capabilities several improvements it offers over prior electrostatic levitators, and overviews thermophysical properties measurement capabilities.

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