Lunar Polar Ice: Implications for Lunar Development

The discovery of water ice at the lunar poles can spur lunar exploration and development and may be a factor in accelerating human exploration beyond the Earth-Moon system. Theoretical models predict the existence of ice in the cold traps, and the Clementine and Lunar Prospector missions have given evidence that ice is indeed present. The Lunar Prospector results suggest that the ice concentrations are low, consistent with a cometary source for ice, which is mixed into the regolith by meteorite impact. Initial concepts for extracting ice from the lunar cold traps, where extreme environmental conditions prevail, have been developed; however, more information on the precise location and physical properties of the ice deposits is required before an approach can be selected. The principal implications of lunar ice development could be: (1) cutting the cost of human exploration missions to the Moon by a factor of two, due to the availability of propellant for returning crews and materials to Earth (this could also accelerate the use of the Moon for scientific outposts and human exploration technology testbeds); and (b) creating an opportunity for export of lunar materials to space at a low cost relative to Earth-to-space transportation. The latter would require the development of a reusable, lunar-based transportation system, fueled on the Moon, and capable of delivering payloads to lunar and Earth orbits. If an export economy is initiated, it is important to consider from the outset the conservation of the lunar ice, which is a nonrenewable resource, and to develop alternatives to its use in transportation systems.