Gamma-ray spectrometry in space studies

The use of gamma-ray spectrometry in studies of the moon and planets is reviewed. The production and distribution of natural and cosmogenic radionuclides in solar-system bodies are examined, cosmic-ray interactions with lunar and planetary matter are analyzed, and some problems in cosmogeny are discussed which have been resolved by studying the radioactivity (primarily gamma-ray emission) of extraterrestrial matter. Instruments and experimental techniques employed in gamma-ray spectrometric studies of extraterrestrial matter are described, and some of the data obtained in these studies are presented. Special attention is given to gamma-ray spectrometry of lunar, planetary, and interplanetary matter from the Luna, Venera, and Mars space probes as well as to laboratory analyses of lunar soil returned to earth by the Luna and Apollo vehicles. Detailed results are reported for space-probe measurements of lunar, Martian, and Venusian gamma radiation.