Gamma-ray and neutron spectrometers (GRS and NS, respectively) are included
in the payload complement of Lunar Prospector (LP) that is currently orbit
ing the Moon. Specific objectives of the GRS are to map abundances of O, Si
, Fe, Ti, U, Th, K, and perhaps, Mg, Al, and Ca, to depths of about 20 cm.
Those of the NS are to search for water ice to depths of about 50 cm near t
he lunar poles and to map regolith maturity. The designs of both spectromet
ers are described and their performance in both the laboratory and in lunar
orbit are presented. (C) 1999 Elsevier Science B.V. All rights reserved.