Luna missions

Among the rarest of all meteorites are the lunar meteorites. Isotopic, mineralogical, and compositional properties of these samples provide positive identification as lunar samples because of the unique properties of lunar materials that have been discovered by extensive analyses of lunar materials returned by the manned ApoUo and unstaffed Luna missions. AH but one of the lunar meteorites that have been found to date have been recovered from Antarctica. 

Six maimed American Apollo missions have returned 382 kg of rocks and soils from the nearside of the Moon. Three automated Soviet Luna missions have also returned small amounts of soils. Most missions sampled maria only the Apollo 14, 15, and 16 missions sampled highlands materials and basin ejecta as well as basalts. Descriptions and geologic significances of the various Apollo and Luna landing sites were given by Hiesinger and Head (2006). 

Lunar mare basalts from the various Apollo and Luna missions are classified by their titanium and potassium contents. After Lucey et al. (2006). 

Samples returned by the Apollo and Luna missions can be readily distinguished based on their contents of FeO and thorium. This may seem like an unlikely choice of chemical components for classification, but they nicely discriminate rock types and are easily measured by remote sensing. The FeO and thorium contents of ferroan anorthosites, mare basalts, impact melt breccias, and lunar meteorites are shown by various symbols in Figure 13.4. 

Different evolutionary histories of other terrestrial planets have influenced the relative concentrations of the transition elements compared to their cosmic abundances, as suggested by geochemical data for surface rocks on the Moon, Mars and Venus (Appendix 1). Chemical analyses of lunar samples returned from the Apollo and Luna missions show that minerals and glasses occurring on the Moon contain high concentrations of Fe and Ti existing as oxidation states Fe(II), Ti(III) and Ti(IV). Some lunar minerals, notably olivine and opaque oxides, also contain significant amounts of Cr(H), Cr(III) and Mn(H). The lack of an atmosphere on the Moon simplifies interpretation of remote-sensed reflectance spectra of its surface. 

Before the advent of the Apollo and Luna missions which retrieved samples from the Moon s surface, meteorites provided the only source of extraterrestrial materials and raised questions about their sources from parent bodies such as asteroids. Visible to near-infrared reflectance spectroscopy, therefore, has been applied extensively to laboratory investigations of meteorites and to remote-sensed measurements of many asteroids (Gaffey, 1976 Gaffey and McCord, 1978 McFadden et al., 1982,1984 Bell and Keil, 1988). 

Compositions of terrestrial planets. Geochemical data derived from lunar samples returned by the Apollo and Luna missions to the Moon, in situ chemical... 

A comprehensive review of the chemical composition of the lunar surface, as ascertained by analysis of samples obtained on the Surveyor and subsequent Apollo and Luna missions, has been collated by Turkevich. The lunar surface is made up of silicate rocks, the principal minerals being calcium-rich feldspars and pyroxenes. In many respects the chemical composition of the maria analysed are similar to those of the terrestrial basalts. The terra regions analysed are distinctly different from the maria in having considerably smaller amounts of iron and titanium and larger amounts of calcium and aluminium. Apollo missions have shown that the lunar mare material is very dry and was produced under relatively reducing conditions. 

Orbital geochemical analyses since the Apollo and Luna sample return missions have revolutionized our understanding of the composition of the crust and mantle. As an example,... 

Fig. Front side of the Moon. Landing sites of all sample-return missions of Apollo and Luna (L16 and L 20) are marked...

The authors wish to express their grateful appreciation to the many friends who aided this project. In South America we were assisted by Mr. Michael Laski and Ms. Sarah Hartley and by the Naval del Sur de Colombia, whose vessels often were our only means of transportation. The Witoto people of La Chorrera and the Mission of La Chorrera were most hospitable, the former providing invaluable access to local psychoactive plants. Drs. Horatio and Isabella Calle of the Universidad Nacional, Bogota, provided valuable information on the endemic tryptamines of Colombian Amazonas. Thanks to the Octavio Luna family, who placed their country home at our disposal for a portion of the time during which the manuscript was written. Thanks especially to Luis Eduardo Luna, whose support and enthusiasm for these ideas helped greatly in their clarification. 

Yttrium has been found in samples of lunar crystalline rocks (namely in relatively yttrium-rich mineral and grain-si/e fractions, light and dark clasts) collected during the Apollo 11-15 and Luna 16 missions. A relatively high amount of yttrium was found in these samples (Gmelin et al. 1980). Indeed, the proportion of yttrium to rare earth elements (REE including ratios and correlations of Y and REE to other elements) was used as a criterion for the classification of lunar rocks. Yttrium and Rare Earths were also a subject of study in the space, for example, in stellar spectra in the solar atmosphere, and in different types of meteorites and mesosiderites. 

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