‘One of the pleasant ironies of the Apollo program was that it took a trip to the moon to teach us how to uncover the secrets contained in primitive meteorites.’ That is Robert N. Clayton's way of saying that he believes techniques originally developed to analyze lunar material in minute amounts are at least partly responsible for the new resurgence in meteoritic research.

Clayton, chairman of the Department of Geophysical Sciences and professor in the Enrico Fermi Institute at the University of Chicago, uses an ion microprobe to study anomalous magnesium in tiny extraterrestrial dust grains. The ion microprobe bombards samples with a finely focused beam of charged particles to remove material to be analyzed. The instrument is unique in its capability to measure isotopic ratios in specks of matter as fine as 10 fim across; more than 2500 mineral grains this size would have to be placed end to end to span a single inch.