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.

Abstract Near–Earth asteroids and comets, collectively the near-Earth objects (NEOs), represent a large population of minor planetary bodies whose orbits lie mostly within the zone between Venus and Mars. Many of these objects cross Earth’s orbit, providing relatively easy access from Earth for manned or robotic sampling and exploration missions with fewer propulsion requirements than trips to the Moon or to Mars. This chapter provides a review of NEOs in the context of supporting, through in-situ resource utilization, an active and expanding space exploration and resource development program capable of becoming self-funding and supporting a solar systemwide expansion program. The NEO compositions range from highly metallic asteroids composed predominantly of iron, nickel, and cobalt to cometlike objects composed of frozen water and gases of various compositions. The NEOs are the most easily accessible objects in near–Earth space, and they are numerous. As of January 2011, a total of 7872 NEOs had been identified. The number of NEOs with diameters greater than 1 km (>0.6 mi) reached 1269 by June 2012. Moreover, 1176 have been identified as potentially hazardous Earth impactors by the National Aeronautics and Space Administration’s Near–Earth Object Program, approaching Earth to within 0.05 astronomical units or approximately 7,480,000 km (4,647,860 mi). The value of NEOs for space exploration may far exceed the immediate scientific information that they provide on the origin of the solar system: NEOs have the potential to provide fuel for rockets; oxygen and life support materials for explorers; valuable materials and metals for construction in space; and critical, strategic, and highly valuable materials for Earth. Water ice derived from extinct NEO comets or water–rich asteroids can be refined to provide liquid oxygen and liquid hydrogen for rocket fuel and the oxygen necessary for life support. Carbonaceous chondrites contain kerogenlike compounds that can support the immense carbon chemistry developed for our petroleum industry, and metallic asteroids contain platinum–group and rare–earth elements that have been conservatively valued in the hundreds of billions to trillions of dollars if they were made available in Earth markets. These resources are accessible using existing rockets and boosters, but these existing systems and technologies are nearly 50 years out–of–date. Active space exploration and development programs require highly efficient nuclear rockets and space–based nuclear power systems to reduce launch costs to economically tolerable numbers and to provide the heavy–lift capacity and highly efficient rocket engines for crew health and safety and minimum duration missions. Once flight launches are outside Earth’s atmosphere, the NEOs can provide nearly unlimited resources for further exploration.

Abstract The recent detection of plumes of methane venting into the Martian atmosphere indicates the probable presence of a substantial subsurface hydrocarbon reservoir. Whatever the immediate source of this methane, its production(whether by biogenic or abiogenic process) almost certainly occurred in association with the presence of liquid water in the deep (>5+ km [>3+ mi]) subsurface, where geothermal heating is thought to be sufficient to raise crustal temperatures above the freezing point of water. Indeed, a geologicevidence that the planet once possessed vast reservoirs of subpermafrost groundwater that may persist to the present day exists. If so, then methanegeneration has likely spanned a similar period of time, extending over a considerable part of the geologic history of Mars. As on Earth, the ventingof natural gas on Mars indicates that substantial amounts of gas are likely present, either dissolved in groundwater or as pockets of pore–filling free gas beneath the depth where the pressure–temperature conditions permitthe formation of gas hydrate. Hydrate formation requires the presence of either liquid water or ice. The amount of water on Mars is unknown; however,the present best geologic estimates suggest that the equivalent of a global layer of water 0.5–1 km (0.3–0.6 mi) deep may be stored as ground ice and groundwater beneath the surface. The detection of methane establishes the subsurface of Mars as a hydrocarbon province, at least in the vicinity of the plumes. Hydrocarbon system analysis indicates that methane gas and hydrate deposits may occur in the subsurface to depths ranging from approximately 10 m (~30 ft) to 20 km (10 mi). The shallow methane deposits may constitute a critical potential resource that could make Mars an enabling.stepping stone for the sustainable exploration of the solar system. They provide the basis for constructing facilities and machines from local Martian resources and for making higher energy–density chemical rocket fuels for both return journeys to Earth and for more distant exploration.