SHS for Space Exploration

For over past years, interest of leading space agencies (NASA, JAXA, ESA, RSA, etc.) in SHS experiments under microgravity conditions has been increasingly growing. The first SHS experiments during a parabolic flight in Russia and aboard the MIR Space station gave promising results. Similar studies are now being carried out in various countries. The obtained data and assimilated experience have shown that SHS reactions can be used for (a) synthesis of high-porosity materials and regulation of structure formation in combustion products, (b) preparation of skeleton structures by combustion of particles suspended in vacuum, (c) generation of thermal energy, (d) generation of incandescent radiation, and (e) for in-space fabrication and in-situ repair works (welding, joining, cutting, coating, near-net-shape production, etc.). However, the results of the above studies (strongly scattered in the literature) still seem insufficient for elucidating the mechanism of combustion in. Indeed, the experiments were carried out by different researchers for a dozen of systems and for strongly different duration of microgravity (drop towers, parabolic flight of a plane, parabolic flight of a spacecraft, in space stations). No correlation has been made with the available data of SHS studies (oriented largely on practical implementation) in conditions of artificial gravity. In experiments, the combustion wave has enough time to spread over the sample while the structure formation, may not have. This implies that the process of wave propagation should always be identical, irrespective of the type of experimental technique and place of experiment. SHS experiments in space are attractive because (a) of low energy requirements, (b) processing cycle is short, (c) of process simplicity, (d) of versatility (wide range of suitable materials, and (e) the use of in-situ resources possible. To date, SHS experiments has already been performed aboard the International Space Station (ISS). Space technology has been developed for frontier exploration not only around the Earth orbit environment but also to the Moon, Mars, etc

Generation of charge carriers during combustion synthesis of sulfides

Recent experimental studies on generation of electric voltage during combustion synthesis of zinc sulfide (ZnS) have revealed high-voltage signals (4 V) with a duration of around 1 s, which is at least four times higher than those produced by the gas-solid and solid-solid combustion reactions studied previously. These data have raised the question about mechanism of the phenomenon. In this work, we developed a novel (distributed) model describing the generation electric potential during combustion synthesis of sulfides (CSS). Simulations of the evolution in the behavior of charge carriers and voltage profiles suggest that it is the emission of negatively charged sulfur ions as well as electrons that has a strong impact on the amplitude and temporal evolution of combustion-induced voltage