Testing The boot soles were tested at NASA’s simulated moon surface laboratory where an area of slag, limestone and feather rock served to duplicate the most severe surface conditions anticipated on the moon. Despite suffering some surface wear and tear, it was found that the thermal properties of the boots were not affected. As it turned out, the moon ‘soil’ was much finer than expected. The lunar dust could be easily brushed off, and there was little or no surface degradation of the sole when examined by the astronauts. The lunar overshoe was one of the few components whose design, at least externally, remained unchanged throughout the Apollo moon landings - a fine testament to the essential correctness of the final design.
NASA