Recently, synthesis of diamond thin films are attempted by various CVD methods with gas or liquid carbon sources. Also, most of experiments are attempted to use flow system which needs charge and discharge gas. Solid carbon source is much better than gas or liquid carbon source for closed system. Closed system is not necessary charge and discharge gas, and much easier for simplifying of apparatus and reducing the weight and space. Therefore closed system is much better than flow system for microgravity environment. We synthesized diamond from graphite on the ground. Chamber size is 100 mm in inner diameter and 100 mm in height. Graphite rod was inserted into spiral coiled W filament and Si or Mo substrate was mounted 2.0 mm under the filament. Hydrogen gas was introduced into the chamber. Graphite is heated by the filament and diamond thin films are deposited on Si or Mo substrate.
Titanium carbide foams were prepared by self-propagation high temperature synthesis under terrestrial (1-g) and microgravity (µ-g) conditions. Carbon black was used as carbiding source and to investigate its role on pore generation. It was confirmed that non-decomposing substances in carbon black play the main role in the foaming. The lattice constant of the synthesized titanium carbide increased with increasing packing density of the starting powder compact when synthesized in air, while it was nearly independent of the packing density when the compact was synthesized in Ar.The effect of gravity on the synthesis was also elucidated. The microstructure of the synthesized titanium carbide under µ-g was finer than that under l g. The reaction velocity under µ-g was higher than that under 1-g, resulting in a smaller elongation.
A technique for preparation of conductive thin films of polypyrrole in 10 seconds was developed using electrochemical polymerization and metal dithiolene complexes as electrolyte to detect the effect of microgravity environment available in a drop tube. Under microgravity, solute migrates less efficiently due to suppressed convection of solution and the reaction rate is reduced. The polypyrrole thin film prepared under microgravity contains less anion metal complex and is more electrochemically stable than in ground-based polypyrrole.
Recently, requests for the telescience from the scientists in the space experiment fields have been emphasized. In this paper, the general ideas of telescience, its history, Japan's purposes, the develop ment efforts, and the results of recent testbed experiments are descrived to respond to the emphasized telescience requests.
For the efficient and improved space experiments in JEM, we have continued the telescience technology development effort since 1987. Based on the real space environment experiments on the space shuttle, we have begun the new telescience activities for the initial JEM in 1999.
Years of promises about the commercial uses of space are finally coming true for some U.S. industries. Experiments performed in microgravity have produced new products and services for private companies. It is only a matter of time before profits follow.