Ernest J. Franzgrote

Chemical Analysis of the Moon at the Surveyor V Landing Site

The chemical composition of the lunar surface material at a maria landing site has been determined by the alpha-scattering technique. Oxygen, silicon, and aluminum have been identified in the preliminary evaluation of the data. The general chemical composition is similar to that of a silicate of a basaltic type.

Chemical Analysis of the Moon at the Surveyor VI Landing Site: Preliminary Results

The alpha-scattering experiment aboard Surveyor VII has provided a chemical analysis of the moon in the area of the crater Tycho. The preliminary results indicate a chemical composition similar to that already found at two mare sites, but with a lower concentration of elements of the iron group (titanium through copper).

Chemical Composition of the Lunar Surface in Mare Tranquillitatis

More precise and comprehensive analytical results have been derived for lunar material at the Surveyor V landing site from alpha-scattering data. The composition is, in general, basaltic; the low sodium and high titanium contents, however, are distinctly different from the abundances in meteorites or common terrestrial rocks.

Chemical Composition of the Lunar Surface in a Terra Region near the Crater Tycho

More precise and comprehensive analytical results for lunar surface material in a terra region have been derived from the data of the alpha-scattering experiment on Surveyor 7. The silicon content and the low sodium abundance are close to that of mare material. The abundances of titanium and iron are at least a factor of 2 lower, whereas the abundances of aluminum and calcium are significantly higher. The analytical results provide direct evidence for chemical differentiation in the moon and indicate a lunar crust of appreciably lower density than the whole moon and with lower density and higher albedo than lunar mare material.

Alpha Radioactivity of the Lunar Surface at the Landing Sites of Surveyors 5,6, and 7

Evidence has been obtained for a radioactive deposit on the lunar surface at Mare Tranquillitatis with a total intensity of 0.09 � 0.03 alpha disintegration per second per square centimeter. The presence of polonium-210 in amounts that are close to equilibrium indicates a continuous turnover rate of lunar material at this site of less than 0.1 micrometer per year. The lack of such a deposit at two other lunar sites suggests lower local concentrations of uranium there.

Instrument for Lunar Surface Chemical Analysis

An instrument has been designed and constructed which utilizes the interactions of monoenergetic alpha particles with matter for surface chemical analysis. The source of alpha particles is a radioactive nuclide, such as 242Cm. The energy spectra of backscattered alpha particles are measured with semiconductor detectors. Other detectors (with gold foils over them to eliminate alpha particles) register protons from α,p reactions. Transistorized electronics provide 128‐channel pulse height analyzers for both alpha and proton spectra. The first prototype instrument designed for the presently planned Surveyor Lunar Missions weighs less than 4 kg and uses less than 1.3 W.