Stock Photo - 03/09/2001 ___ The 2001 Mars Odyssey Orbiter sits in the Spacecraft Assembly and Encapsulation Facility SAEF 2 while components undergo testing. Workers in the foreground check instruments during testing of the UHF antenna. Scheduled for launch April 7, 2001, the orbiter contains three science instruments: THEMIS, the Gamma Ray Spectrometer GRS, and the Mars Radiation Environment Experiment MARIE. THEMIS will map the mineralogy and morphology of the Martian surface using a high_resolution camera and a thermal infrared imaging spectrometer. The GRS will achieve global mapping of the elemental composition of the surface and determine the abundance of hydrogen in the shallow subsurface. The MARIE will characterize aspects of the near_space radiation environment with regards to the radiation_related risk to human explorers