Experimental study on simulated lunar soil. High voltage breakdown and electrical insulation characteristics

A low-mass solution to electrical insulation in the lunar environment may be possible by embedding bare HV conductors within the lunar soil itself. In the paper, a 'standard' NASA soil (lunar simulant) representing chemical and physical conditions found in some lunar samples was used in laboratory experiments, and its HV electrical breakdown data were presented for the first time. Insulation characteristics and leakage currents representative of variations in nonlinear resistivity of the soil were investigated. The data were compared to earlier published data for a typical lunar soil's electrical characteristics. A pair of bare planar transmission lines, having a parallel plate geometry, was buried in the lunar soil simulant and used to measure the simulant's electrical parameters. The soil simulant and the electrode assembly were in a high vacuum environment throughout the experiment series. For this parallel plate electrode configuration, electrical breakdown limits and temporal evolution of voltage breakdown of the simulated lunar soil were measured. The data were analyzed in terms of physical mechanisms. Results presented may find applications in terrestrial uses of porous ceramics as insulators as well as in future lunar colony transmission line insulation techniques and design purposes.