EDITORIAL
Planetary Rock Analysis This past July 20 marked the twentieth anniversary of the first landing of man on the moon. Apollo 11 astronauts Neil Armstrong, Edwin (Buzz) Aldrin, Jr., and Michael Collins returned to Earth with 48 pounds of lunar rock and soil. These samples were then studied by 142 principal investigators from laboratories around the world who had been selected by the National Aeronautics and Space Administration (NASA) for the Lunar Analysis Program. Between 1969 and 1974 a total of six missions (Apollo 11, 12,14,15, 16, and 17) returned a wealth of samples from different locations on the moon. Study of the Apollo lunar samples represented a unique scientific adventure and an intellectual challenge of the first magnitude. As one might expect, chemical analysis—particularly trace analysis—played a very important role in the Lunar Analysis Program. In addition to chemical and isotopic analysis, mineralogy and petrology, physical studies, and organic and biochemical analyses were performed. By comparing the elemental abundance patterns of lunar material with those of solar, meteoritic, and terrestrial materials, some insight into the cosmological history of the moon was obtained. The chemical composition of the lunar surface was found to reflect at least three major processes: chemical fractionations
during accretion of the moon from the solar nebula, magnetic differentiation, and infall of meteorites and cosmic dust. Among the analytical techniques used to study lunar materials were activation analysis, atomic spectroscopy, Auger spectroscopy, gamma spectrometry for radioactive isotopes, inert gas fusion and combustion chromatographic analysis, mass spectrometry, electron and ion microprobe analysis, Môssbauer spectroscopy, scanning electron microscopy, spectrophotometry, wet chemistry, and X-ray fluorescence spectroscopy. This monumental analysis program has contributed significantly to our current knowledge of the moon. However, further planetary studies are vitally needed to better understand our solar system. Much of the future success of such studies will depend upon highquality chemical analysis. For historical interest, I suggest seeing a 16-mm film, "Museum of the Solar System," which was presented by the American Chemical Society in 1971. The film presents scientific studies of the lunar samples by seven investigators, including the Nobel laureate Harold C. Urey.
ANALYTICAL CHEMISTRY, VOL. 61, NO. 17, SEPTEMBER 1, 1989 · 945 A
