Experimental Determination of the Thermal Conductivity of JSC-1A under Vacuum Conditions with a Cavity Receiver Breadboard Design for Regolith Heating

Thermal processing is an effective way to extract solar wind implanted particles (SWIP) from lunar regolith. For heating a larger amount the behavior of its thermal properties, especially conductivity, at higher temperatures is essential. The goal was the experimen- tal determination of thermal conductivity of the regolith simulant JSC-1A under vacuum conditions (10e-5 mbar) at temperatures of up to 650C. Literature provides some data of measured thermal conductivities of lunar regolith which vary from 9x10e-3 to 25x10e-3 W/(m K) for temperatures between -20C and 20C under vacuum conditions. This variation and uncertainty of data required new measurements and more research on this topic. Therefore, a cavity receiver breadboard was used which was originally designed to optimize homogenous heating of JSC-1A. A steady state mea- surement method was applied to this experiment, where mean temperatures of the JSC-1A sample of up to 650C were reached. The results show a cubic increase of the thermal conductivity as a function of temperature from 8x10e-3 W/(m K) at 150C to 33x10e-3 W/(m K) at 650C. This increase seems to be caused by heat transfer due to radiation, the dominating heat conduction mechanism in powders under vacuum conditions. In general, the comparison of the results with past studies of different authors shows the same order of magnitude. After having a first im- pression, more substantial work will be necessary to improve knowledge about thermal conductivity of real lunar regolith and its simulants.     «

Thermal processing is an effective way to extract solar wind implanted particles (SWIP) from lunar regolith. For heating a larger amount the behavior of its thermal properties, especially conductivity, at higher temperatures is essential. The goal was the experimen- tal determination of thermal conductivity of the regolith simulant JSC-1A under vacuum conditions (10e-5 mbar) at temperatures of up to 650C. Literature provides some data of measured thermal conductivities of lunar regolith which va...     »