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екатерина в категроии Английский язык, вопрос открыт 06.05.2018 в 19:33


This label «Made in Space» for industrial materials will probably surprise no one in the not so distant future. They may include superconductors, new kinds of alloys, substances with peculiar magnetic properties, supertransparent laser glass1, polymers, plastics, and so on. Numerous experiments carried out at the Russian orbital space stations have paved the way2 to the development of methods and means of industrial production of new materials of better quality on board a spacecraft3. Experts estimate that within a few coming years industrial production of various materials will be started in space.

Conditions on board a space vehicle orbiting Earth greatly differ from those on its surface. However, all of these conditions can be simulated4 on Earth, except for one — prolonged weightlessness. Weightlessness can be created on Earth, but only for a few seconds. A space flight is another matter: a satellite orbiting Earth is in a dynamic zero-gravity state, i.e., when gravity is cancelled out5 by inertia.

What can weightlessness be used for? Many well-known processes go on differently due to the absence of weight. The Archimedes principle is no longer valid and, consequently, stable-state6 liquid mixtures can be obtained, the components of which would immediately separate on Earth because of different density. In case of melts7 of metals, glasses or semiconductors, they can be cooled down to the solidification point even in space and then brought back to Earth. Such materials will possess quite unusual qualities.

In space there is no gravitational convection8, i.e., movements of gases or liquids caused by difference of temperatures. It is well-known that various defects in semiconductors occur because of convection. Biochemists also have to deal with the worst aspects of convection, for example, in the production of superpure biologically active substances. Convection makes it very difficult on Earth.

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