Retrieval of Asteroidal Materials

Earlier scenarios for mass-driver retrieval of asteroidal materials have been tested and refined after new data were considered on mass-driver performance, favorable delta-V opportunities to Earth-approaching asteroids with gravity assists, designs for mining equipment, opportunities for processing volatiles and free metals at the asteroid, mission scenarios, and parametric studies of the most significant variables. We conclude that the asteroid-retrieval option is competitive with the retrieval of lunar materials for space manufacturing, while a carbonaceous object would provide a distinctive advantage over the Earth as a source of consumables and raw materials for biomass in space settlements during the 1990's. We recommend immediate studies on asteroid-retrieval mission opportunities, an increased search and followup program, precursor missions, trade-offs with the Moon and Earth as sources of materials, and supporting technology.