The 2001 Mars Odyssey Orbiter Mission had 5 detailed science      goals each of which was to be addressed by a specific      instrument [JPLD-16303].        (1) GRS globally mapped the elemental composition of the            surface.        (2) GRS determined the abundance of hydrogen in the            shallow subsurface.        (3) THEMIS acquired high spatial and spectral            resolution images of the surface mineralogy.        (4) THEMIS provided information of the morphology of            the Martian surface.        (5) MARIE characterized the Martian near-surface            radiation environment as related to radiation-induced            risk to human explorers.      During the Extended Mission, the science teams operated the      instruments mostly in their nominal modes, with the scientific      objectives of:        (1) Completing coverage,        (2) Improving the signal-to-noise ratio of measurements,        (3) Observing interannual variations and other secular changes,        (4) Acquiring data complementary to those obtained by other            spacecraft at Mars.      Each instrument had additional, more specific objectives:    THEMIS    ------      The Thermal Emission Imaging System (THEMIS) had five, more      narrowly defined science objectives for the Primary Mission:      (1) To determine the mineralogy and petrology of localized          deposits associated with hydrothermal or sub-aqueous          environments, and to identify sample return sites likely          to represent these environments.      (2) To search for pre-dawn thermal anomalies associated with          active sub-surface hydrothermal systems.      (3) To study small-scale geologic processes and landing site          characteristics using morphologic and thermophysical          properties.      (4) To investigate polar cap processes at all seasons using          infrared observations at high spatial resolution.      (5) To provide a direct link to the global hyperspectral          mineral mapping from the MGS TES by utilizing the same          infrared spectral region at high (100m) spatial          resolution.      Additional objectives in the Extended Mission:      (6) To complete the global mapping of surface mineralogy.      (7) To build global mosaics.      (8) To monitor polar-cap growth, retreat, volatile exchange,          and energy balance.      (9) Monitor the temporal and spatial variability of dust and          water ice aerosols.    GRS    ---      The Gamma Ray Spectrometer (GRS) had the following more      specific science objectives [JPLD-16303] for the Primary      Mission:      (1) To determine quantitatively the elemental abundances of          the martian surface to an accuracy of 10% or better at a          spatial resolution of 300 km.      (2) To map the abundances of CO2 and hydrogen (with water          depth inferred) over the entire planet.      (3) To determine the depth of the seasonal polar ice caps and          their variation with time.      (4) To study the nature of cosmic gamma-ray bursts.      Additional objectives in the Extended Mission:      (5) To map additional elements.      (6) To monitor seasonal and interannual variations.      (7) To simultaneously observe the atmosphere with the Mars          Climate Sounder on the Mars Reconnaissance Orbiter.      (8) To locate gamma-ray bursts.    MARIE    -----      The Martian Radiation Environment Experiment (MARIE) had the      following more specific science objectives:      (1) To measure radiation from the Sun and from sources beyond          the solar system that could cause cancer or damage the          central nervous system.      (2) To measure for the first time the radiation environment          outside the Earth's protective magnetosphere.      (3) To predict anticipated radiation doses that might be          experienced by future astronauts and help determine          possible effects of Martian radiation on human beings.    RADIO SCIENCE    -------------      Although not a recognized science objective of the 2001 Mars      Odyssey mission, improvement of models of the Mars gravity      field was supported by collection and archiving of spacecraft      radio tracking data by the Planetary Data System.    EXTENDED MISSION THEMES    -----------------------      Several themes were common to the extended mission science plans.      First was the opportunity to collect data for an additional Mars      year, to observe and evaluate interannual variability. The Odyssey      instrument complement could observe many aspects of the Martian      annual cycle, including volatile deposition and sublimation in      polar regions, dust storm occurrence, and cloud and aerosol      phenomena. Second, for the Gamma Ray Spectrometer (GRS), the      increased temporal coverage allowed monitoring of the Martian      environment as the solar cycle approached its minimum. This      affected the radiation environment, and the increased flux of      galactic cosmic rays increased the production of secondary      neutrons and gamma rays, providing an enhanced signal for the      GRS instruments' studies of the Martian surface. Finally,      additional observations also increased the quality of many of      the Odyssey data sets. For GRS, the added accumulation time of      observation allowed the team to reduce the uncertainties on the      elemental abundances, to generate higher resolution maps of many      of the elements, and to derive abundances for elements that were      not previously mappable. For THEMIS, the extended mission provided      the time and bandwidth to obtain early time-of-day infrared data      for much of the planet and to complete high-resolution visible      image mosaics.