Lunar resource surveys from orbit

The chemical composition of lunar soil and rocks is known now for nine surface sites, by analysis of returned samples. Three classes of silicate material, mare basalt, KREEP, and highland material (sometimes called ANT) have been identified as major components. Gamma-ray and X-ray instruments have mapped the Apollo 15 and 16 ground tracks for major elements, K, and Th. It is hoped that the Lunar Polar Orbiter will carry instruments capable of producing a chemical map of the entire moon. The most exciting possibility is that ice may exist in shadowed regions near the lunar pole.