Gamma-Ray Spectrometer (GRS) is developed for global exploration of elementary composition of Mars’ surface and searching for subsurface water ice by methods of gamma ray and neutron spectroscopy.

GRS is a re-designed version of the “Mars Observer” gamma-ray spectrometer. It is the last instrument of the “Mars Observer” mission to be flown to Mars. At early 2002, eight years after the first attempt, GRS will start the global scanning of Mars.

This GRS equipment includes:

• Gamma-ray Spectrometer itself (GRS) with cooled detector of highly purified germanium developed in the Lunar and Planetary Laboratory of the University of Arizona  (Tucson, Arizona, USA). Dr. William Boynton is Team Leader of this experiment and of all GRS project.

• Neutron Spectrometer (NS) for detection of thermal and epithermal neutrons, developed in Los Alamos National Laboratory (Los Alamos, New Mexico, USA). Dr. William Feldman is Team Leader of this experiment.

• High Energy Neutron Detector (HEND) for detection of epithermal, resonance and fast neutrons, developed in Space Research Institute (Moscow, Russia). Dr. Igor Mitrofanov is Principal Investigator of this experiment.

The main characteristics of GRS are presented in Table 2.

The full description of GRS is on site http://grs.lpl.arizona.edu/