Engineering topics

Cameron, Eugene N.

Publications and source records attributed to Cameron, Eugene N..

3 records

NASA NTRS1992

Helium mining on the Moon: Site selection and evaluation

The feasibility 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 evaluation 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 samples: (1) Regoliths from areas underlain by highland materials contain less than 20 wppm He; (2) Certain maria regoliths contain less than 20 wppm He, but other contain 25 to 49 wppm; (3) The He content of a mare regolith is a function of its composition; regoliths rich in Ti are relatively rich in He; and (4) He is concentrated in the less than 100-micron size fractions of regoliths. The first three findings suggest that maria are the most promising mining sites, specifically, those that have high-Ti regoliths. Information on the regional distribution and extent of high-Ti regoliths comes mainly from two sources: direct sampling by various Apollo and Luna missions, and remote sensing by gamma-ray spectroscopy and Earth-based measurements of lunar spectral reflectance. Sampling provides essential control on calibration and interpretation of data from remote sensing. These data indicate that Mare Tranquillitatis is the principal area of high-Ti regolith of the eastern nearside, but large areas of high-Ti regolith are indicated in the Imbrium and Procellarum regions. Recovery of significant amounts of He-3 will require mining billions of tonnes of regolith. Large individual areas suitable for mining must therefore be delineated. The concentration of He in the finer size fractions and considerations of ease of mining mean that mining areas must be as free as possible of sizable craters and blocks of rock. Pending additional lunar missions, information regarding these features must be obtained from lunar photographs, photogeologic maps, and radar surveys. The present study is decidedly preliminary; available information is much to limited to permit even a close approach to final evaluations. As a prelude to recovery of He from the Moon, systematic exploration and sampling of high-Ti regoliths should therefore have a high priority in future lunar missions.

Cameron, Eugene N.↗

NASA NTRS1991

Helium resources of Mare Tranquillitatis

Wisconsin Center for Space Automation and Robotics, Univ. of Wisc., Madison, Wisc. Mare Tranquillitatis, about 300000 sq km in area, is currently the most promising lunar source of He-3 for fueling fusion power plants on Earth. About 60 pct. of the mare regolith consists of particles 100 microns or less in diameter. Helium and other gases derived from the solar wind are concentrated in the fine size fractions. Studies of very small craters indicate that the average regolith exceeds 3 m in areas away from larger craters and other mare features not amenable to mining. There is no evidence of decrease of helium content of regolith and depth. Helium is known to be enriched in regoliths that are high in TiO2 content. Remote sensing indicates that about 90 pct. of Mare Tranquillitatis is covered by regolith ranging from about 6 to +7.5 pct. TiO2; inferred He contents range from 20 to at least 45 wppm total helium (7 to 18 wppb He-3). Detailed studies of craters and inferred ejecta halos displayed on high resolution photographs of the Apollo 11 and Ranger 8 areas suggest that as much as 50 pct. of the mare regolith may be physically minable, on average, with appropriate mining equipment. Assuming that the average thickness of regolith is 3 m, and that 50 pct. of the mare area is minable, the He-3 content of minable regolith containing 20 to 45 wppm total He is estimated at about 94,000 tonnes.

Cameron, Eugene N.↗

NASA NTRS1988

Mining for helium: Site selection and evaluation

Part of the University of Wisconsin study of the feasibility of recovering He-3 from the moon is selection and evaluation of potential mining sites. Selection and evaluation are based primarily on salient findings by investigators: (1) Regoliths from areas underlain by highland materials contain less than 20 wppm He; (2) Regoliths of certain maria or parts of maria also contain less than 20 wppm He, but mare regoliths at the Apollo 11 and 17 sites contain 25 to 49 wppm He; (3) The helium content of a regolith is a function of its composition; and (4) Helium is concentrated in the -50 micron size fractions of regoliths. In site selection, the concern is with the compositions of lunar regoliths, in particular with their titanium contents. It is widely accepted that compositions of mare regoliths are controlled by the nature of the underlying basalts from which the regoliths are largely derived. The distribution and extent of the three groups of basalts and the regoliths derived from them are the first basis for site selection and evaluation. Other considerations are briefly discussed.

Cameron, Eugene N.↗