Apollo lunar orbital science.

The Apollo 15 and 16 experiments are discussed. The formal scientific experiments conducted in lunar orbit are listed in an appendix. The gamma ray spectrometer performed a compositional survey of the upper 30 cm of the lunar surface by observing the gamma rays emitted during the radioactive decay of naturally occurring radioisotopes and their daughter products, and of the radioisotopes produced by cosmic ray bombardment of lunar surface materials. The results from the Apollo 15 X-ray spectrometer have shown excellent correlation between returned samples and gross lunar features. The various systems and experiments are described in detail.