Mars Odyssey today is a step closer toward its mission of mapping the Red Planet. Odyssey is carrying the Gamma Ray Spectrometer (GRS), built under the direction of Professor William V. Boynton at the University of Arizona Lunar and Planetary Laboratory. The GRS is a suite of three instruments: the Gamma Subsystem, built by the UA, the Neutron Spectrometer, built by Los Alamos National Laboratory and the High Energy Neutron Detector, built by the Space Research Institute, Moscow. Boynton and other Mars Odyssey scientists will detail their science objectives Friday, March 1, at a news conference to be telecast from the NASA Jet Propulsion Laboratory in Pasadena, California.