The Significance of Lunar Water Ice and Other Mineral Resources for Rocket Propellants and Human Settlement of the Moon

Abstract Future success in exploration and human habitation of the solar system will depend on space missions and settlements becoming more self-sustaining through exploitation of extraterrestrial (i.e., local) energy and material resources. For example, the Moon contains a wide variety of energy minerals and other resources that can potentially be used for manufacture of propellants for space transportation, volatiles for manufacture of chemicals, and metals for construction of solar power facilities, industrial plants, and structures for human habitation. If water ice in polar regions on the Moon is proven to exist in large quantities, these resources could not only support human habitation but could also be used to manufacture rocket propellants, reducing dependency on Earth for these resources, thereby making human space exploration more economically viable. Moreover, the lower gravity well of the Moon could be used as a launching site for missions to Mars and other worlds in the solar system, given the possibility of water-ice and other lunar resources. New exploration tools will need to be developed to fully and accurately characterize the potential lunar resource base. For example, detection and quantification of suspected water-ice resource in lunar polar regions in recent missions involve an array of technologies not commonly used in hydrocarbon exploration on Earth, such as synthetic aperture radar, epithermal neutron detectors, and imaging of reflected ultraviolet starlight using Lyman-alpha scattering properties. Optimal locations for potential lunar bases and industrial facilities reflect several factors that include the distribution of water ice, volatiles (nitrogen), nuclear materials (helium-3, thorium, and uranium), and metals (titanium, magnesium, and iron). Other important factors are the duration of insolation (sunlight), where solar power facilities could be constructed in polar areas with constant or near-constant illumination, as well as strategies that involve key orbital positions (Lagrangian points) to maximize fuel resources using less overall delta-v, defined as incremental change in spacecraft velocity to achieve a new orbital configuration.