r_OT FILMED

The feasibih'Cy of recovering helium (He) from the Moon as a source of fusion energy on Earth is currently being studied at the University of Wisconsin. Part of this study is selection and etcduation of potential sites for lunar He mining. Selection and evaluation of potential mining sites are based on four salient findings by various investigators of lunar sarape: (1) Regoliths from areas underlain by highland materials contain less than 20 uggrm He; (2)Certain mar _ regoUths contain less than 20 _ He, but others contain 25 to 49 wtgnm; (3) The He content of a _ regolith is a function of its composition; regoliths rich in 11 are relatively rich in He; and (4) He is concentrated in the <100-_m size fractions of regoliths. The first three fimlings suggest that maria are the most promising mining sites, specificxdly, those that hate higlr11 regoliths. Information on the regional distribution and extent of higtr 11 regoliths comes mainly from turn sources: direct sampling by various Apollo and Luna missions, and remote sensing by gammavray spectroscopy and Earth-based measurements of lunar spectral reflectance. Sampling provides essential control on cal_aration and interpretation of data from remote sensing. These data indicate that Mare Tranquillitatis is the l_ncipal area of higl_11 regolith of the eastern nearside, but large areas of high- 11 regoUth are indicated in the imbn'um and ProceUarum regions. Recovery of significant amounts of He-3 will require mining billions of tonnes of regolith. Larg