Technicians check out the Gamma Ray Spectrometer before it is installed on the Mars Odyssey Orbiter in the Spacecraft Assembly.

Technicians check out the Gamma Ray Spectrometer (GRS) before it is installed on the Mars Odyssey Orbiter in the Spacecraft Assembly and Encapsulation Facility II (SAEF II) .; The orbiter will carry three science instruments: the Thermal Emission Imaging System (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 GRS is a rebuild of the instrument lost with the Mars Observer mission.] The MARIE will characterize aspects of the near-space radiation environment with regards to the radiation-related risk to human explorers. The Mars Odyssey Orbiter is scheduled for launch on April 7, 2001, aboard a Delta 7925 rocket from Launch Pad 17-A, Cape Canaveral Air Force Station