Technology for water mining on the Moon without ice phase change

Abstract

An analytical study into technologies developed for mining water on the Moon has been carried out, and its results demonstrate that methods without the ice phase change are energy efficient. Based on an analysis of temperature distribution over the regolith depth at the lunar poles, it was found that water in t he form of ice can be present at depths less than 11 cm. According to their properties, ice regoliths are not loose rocks like dry regoliths but rather hard. With this in mind, a two-phase technology has been proposed to extract water from ice regolith without the ice phase change: the extracted raw material is first crushed and then separated by screening. The regolith hardness rapidly increases as water content increases. Since the equipment mass and power increase as the material hardness increases, in the first phase of the Moon exploration, it is advisable to mine and process ice regoliths with an ice content of ~1.6 %, which are relatively soft rocks with a hardness of 2. Small mobile excavators, already developed and tested, can be used for digging such materials, and impact crushers with low weight and power can be used for processing the raw materials.        The concept of an integrated system for separating ice from regolith without the ice phase change has been developed based on a selective impact crusher, which combines the operations of crushing the extracted raw materials and separating individual components in one device. Selective impact crushers are the most energy-efficient pieces of equipment for crushing and separating raw materials. The power consumption of the proposed integrated selective crushing system to separate ice from regolith for mining 100 kg of ice per hour is 118 W, which is comparable with the Aqua Factorem system (100 W) and significantly less than the power consumption required for the thermal method, i.e., 800 kW.