Microgravity experiments were conducted using sounding rocket TR-IA in November 1998. This 7th flight was the last for the TR-IA sounding rocket experiment series. Six experiments including one experiment for technology
development were performed. Experimental data and processed samples were obtained for all experiments except for the experiment using Combustion Experiment Module. Besides the scientific and technological knowledge gained throughout this project, a lot was learned in the -Fusion of science and technology- management. These results will contribute to the experiments on the ISS and on the next sounding rocket series for the future.
Interdiffusion coefficients of the InAs-GaAs system and self diffusion coefficients of InAs in the system InAs-113 InAs have been measured accurately by using the sounding rocket TR-IA#7 and the shear cell method
combined with glass sealing technique in microgravity. Measured diffusion coefficients were in the range between 1.2 to 4.1 x 10-s m2/sat temperatures between 1070 and 1200°C. Two significant digits were obtained for regular compositional profiles. In the measured temperature range, diffusion coefficients seemed to be dependent on T5•
The experiments of self and mutual diffusion coefficient measurements for liquid Cu-Ag alloys were performed
under the microgravity of TR-IA-7 rocket with the use of diffusion couple method and shear cell technique. Measured temperatures were 1433, 1483 and 1533 K. The shear cell containing ten diffusion couples was developed. It worked successfully to create the liquid columns of all 30 diffusion couples and cutting of these liquid columns into divided pieces without any troubles. The obtained self diffusion coefficients for pure Cu and pure Ag were slightly spoiled by the effect of fluid motion. These data were compared with theoretically calculated values based on the hard sphere model, in which the hard sphere diameters are calculated from the thermodynamic variational theory. The present mutual diffusion data in liquid Cu-Ag alloys were also spoiled by the effect of fluid motion. Discussion is given to the cause of this fluid motion and it is concluded that careful attentions must be paid for the perfect performance of microgravity diffusion experiments particularly in the case of liquid mixtures.
A fundamental study on spray combustion was carried out by using microgravity conditions produced by a 100 m drop shaft. A monodispersed and mono-sized droplet cloud was used for experiments as a simple model of a spray. Such a droplet cloud was generated by using the principle of the Wilson's cloud chamber. Methanol droplet clouds were employed in the present work. Pressure was set 0.2 MPa for all experiments. The mean droplet diameter and the ratio of the liquid fuel mass to the total fuel mass were varied in the rage of 7-45 µm and 0-60%, respectively. Almost monodispersed and mono-sized droplet clouds were generated and ignited successfully under microgravity conditions. It was found that the flame speed of fuel droplet clouds exceeds that of premixed gases of the same total equivalence ratio in two regions of the total equivalence ratio. One region exists in the lean side and the other exists in the rich side. For the mixtures of 0.8 in the total equivalence ratio, the flame speed takes the maximum value when the mean droplet diameter is about 11 µm and the liquid equivalence ratio is about 0.2.
We performed sounding rocket microgravity experiments to evaluate the sample position control system for an Electrostatic Levitation Furnace(ELF) for the International Space Station, and we also performed containerless processing of BiFe03 to evaluate its structure. The experiments are successfully conducted and we obtained technical data for the sample positioning function as well as a processed sample BiFe03. The sample position control function was successfully completed, however, sample fluctuation was observed when the sample was heated and melted. The cause of the fluctuation is due to charge loss of the sample. This result indicates us that position control system of the ELF should be detect the charge loss and adjust PID parameters automatically. From the results of sample evaluation, fine structure and macroscopic segregation have been found.
Epidermal growth factor (EGF) activates a well-characterized signal transduction cascade in most cell types and this activation leads to increase cell proliferation. Among the early effects envoked by EGF are the kinase activation of EGF receptor, the activation of mitogen-activated protein (MAP) kinase cascade and early gene expression such as c-fos. Recently, it was reported that the gravity influences the signal transduction via EGF receptor. To examine the action site of microgravity on EGF signal transduction cascade, osteoblast-like MC3T3-El cells were cultured in the Cell Culture Experiment Module (CCE-7) of the sounding rocket TR-1A7. The EGF-induced phosphorylation of MAP kinase was not affected under short-term microgravity conditions in the sounding rocket compared with the controls grown on the ground. Unfortunately, the cell morphology became too worth to confirm the nuclear translocation of MAP kinase in this experiment.
Temperature change of a BaO- B20 3 glass melt was measured in micro gravity (µg) environment in drop shaft experiments using two different sample-heating methods; a direct heating method and an indirect heating method. In situ observation of the flow pattern in the melt has also been made simultaneously. For the direct heating method, a high rate of thermal convection in the melt was observed at 1 G before a drop. It was observed that the convection rate decreased and the sample temperature increased in µg during the drop. For the indirect heating method, neither the thermal convection nor the sample temperature increase was observed. A mechanism of the temperature rise or the thermal-blanket effect for direct heating was proposed; the heat removal rate from the sample by the inner and atmospheric thermal convection decreased in µg. A simple model for heat transfer based on the sample and furnace configurations used in the present experiments was proposed. The model predicted that the temperature of the sample increased by a greater amount and with a steeper slope with the decreasing atmospheric convection rate in µg, which is in qualitative agreement with the results observed in the drop experiments.
An axially traveling magnetic wave induces a meridional base flow in an electrically conducting molten cylindrical zone. This flow can be beneficial for crystal growth applications. In particular, it can be effectively used to stir the melt in long cylindrical columns. It can also be tailored to modify the thermal and species concentration fields in the melt and to control the interface shape of the growing crystal. The basic theory of such an application is developed and data from a preliminary mercury column experiment are presented.
Solid particles present in the solar system derive from natural origin is termed -dust particles- in general. Dust particles are considered to be supplied from comets, asteroids EKBOs, satellites and planets, and some known as interstellar dust particle from outside the solar system. Since dust particles are thought to be closely related with the evolution of the solar system, study of these materials provides us with crucial information about the history of the solar system. This paper reviews major results of recent studies on dust particles, which utilize space environment experiments. In-situ dust measurements exposed in space environment and dust aggregation experiment under the micro-gravity condition are reviewed in detailed here.
Protein crystallography is a very powerful method to determine the three-dimensional structures of biological macro molecules. Protein structures at atomic resolution is very important not only biologically but also industrially. For exam ple, such structural information can be used for a rational drug design (structure based drug design: SBDD) . However, it is often extremely difficult to obtain the well-diffracting crystals, and the development of techniques to improve crystal quality is a serious problem yet to be solved in protein crystallography. Recently, the microgravity environment attracts attention, which provides the possibility to obtain the improved-quality protein crystals in their larger size and in better molecular order. Here, the current status of protein crystallization, including utilization of microgravity is reviewed from the view points of structural biology and SBDD.
In a gas-liquid two-phase flow, forces such as surface tension, momentum force and gravity affect on the interaction among dispersed phases such as droplets and bubbles, as well as gas and liquid continuous phases. Gas-liquid two-phase flow experiments under µg environment have been increasingly carried out in recent years using drop shafts, aircraft, and space stations, to evaluate the influence of these forces affecting on the phenomena. Apart from the evaluation of the forces, many efforts have been made to conduct experiments to determine the flow mechanism under µg environment which makes it possible to control the two-phase flow experiments by means of non-convection, non-sedimentation/non-buoyancy, non-static pressure, and also non-contact floatation-conditions which are hardly achievable under normal-gravity environment. This report outlines examples of research being conducted on a gas-liquid two-phase flow under µg environment using the JAMIC drop shaft.
The STS-107 is the space mission scheduled to launch in February 2001. NASDA is conducting protein
crystallization experiments by utilizing SPACEHAB's apparatus modules on NASA's space shuttle. In addition to scientific research themes, research themes of NASDA's Pilot Applied Research Program are being carried out. This report explains the main mission, methods of experiments and research themes of above space mission
A micro-gravity working group at the Japan-US Science, Technology & Space Application Program (JUSTSAP) has sponsored a micro-gravity experiment, which was named as Japan-US Thermal Science Acceleration Project (JUSTSAP), performed on board the flight of the Space Shuttle, STS-95 in 1998. The project was successful in achiev ing the identification and promotion of greater cooperation between Japan and US mutual activities. In the JUSTSAP Wokshop '99, the micro-gravity working group has planned two research projects on STS-107 which are protein crystal growth experiments named as JUSPRO (Japan-U.S. Space Protein) and a student educational program as JUSTSAP S*T*A*R*S™. The flight of ST S- 107 is scheduled in the beginning of 2001. Several topics related to the future of JUSTSAP with a particular emphasis on the micro-gravity working group have been also discussed in the '99 Workshop such as (1) Involvement of Hawaiian Entities by direct contact with the University of Hawaii and the Space Grant Office, (2) Membership by seeking greater involvement of industry through the CSC's (NASA sponsored Commercial Space Centers), (3) International Space Policy through the invitation of an international expert on space, (4) Microgravity Working Group Activities by expanding the scope of activities to include the space life sciences area and student programs, etc. These topics will be discussed much in details in the coming 2000 Workshop.