The driving theme of the Mars Exploration Program is to understand the  role of water on Mars and its implications for possible past or  current biological activity.  The Mars Reconnaissance Orbiter (MRO)  Project will pursue this 'Follow-the-Water' strategy by conducting  remote sensing observations that return sets of globally distributed  data that will:  1) advance our understanding of the current Mars  climate, the processes that have formed and modified the surface of  the planet, and the extent to which water has played a role in surface  processes; 2) identify sites of possible aqueous activity indicating  environments that may have been or are conducive to biological  activity; and 3) thus identify and characterize sites for future  landed missions.   The MRO payload is designed to conduct remote sensing science  observations, identify and characterize sites for future landers, and  provide critical telecom/navigation relay capability for follow-on  missions.  The mission will provide global, regional survey, and  targeted observations from a low 255 km by 320 km Mars orbit with a  3:00 P.M. local mean solar time (ascending node).  During the one  Martian year (687 Earth days) primary science phase, the orbiter will  acquire visual and near-infrared high-resolution images of the  planet's surface, monitor atmospheric weather and climate, and search  the upper crust for evidence of water.  After this science phase is  completed, the orbiter will provide telecommunications support for  spacecraft launched to Mars in the 2007 and 2009 opportunities.  The  primary mission will end on December 31, 2010, approximately 5.5 years  after launch.    Science Questions Addressed  ---------------------------     The MRO mission has the primary objective of placing a science orbiter    into Mars orbit to perform remote sensing investigations that will    characterize the surface, subsurface and atmosphere of the planet and    will identify potential landing sites for future missions.  The MRO    payload will conduct observations in many parts of the electromagnetic    spectrum, including ultraviolet and visible imaging, visible to    near-infrared imaging spectrometry, thermal infrared atmospheric    profiling, and radar subsurface sounding, at spatial resolutions    substantially better than any preceding Mars orbiter.  In pursuit of    its science objectives, the MRO mission will:     - Characterize Mars' seasonal cycles and diurnal variations of water,      dust, and carbon dioxide.    - Characterize Mars' global atmospheric structure, transport, and      surface changes.    - Search sites for evidence of aqueous and/or hydrothermal activity.    - Observe and characterize the detailed stratigraphy, geologic      structure, and composition of Mars surface features.    - Probe the near-surface Martian crust to detect subsurface structure,      including layering and potential reservoirs of water and/or water ice.    - Characterize the Martian gravity field in greater detail relative to      previous Mars missions to improve knowledge of the Martian crust and      lithosphere and potentially of atmospheric mass variation.    - Identify and characterize numerous globally distributed landing sites      with a high potential for scientific discovery by future missions.     In addition, MRO will provide critical telecommunications relay    capability for follow-on missions and will conduct, on a    non-interference basis with the primary mission science, telecom and    navigation demonstrations in support of future Mars Exploration    Program (MEP) activities.  Specifically, the MRO mission will:     - Provide navigation and data relay support services to future MEP      missions.    - Demonstrate Optical Navigation techniques for high precision delivery      of future landed missions.    - Perform an operational demonstration of high data rate Ka-band      telecommunications and navigation services.     Designed to operate after launch for at least 5.4 years, the MRO    orbiter will use a new spacecraft bus design provided by Lockheed    Martin Space Systems Company, Space Exploration Systems Division in    Denver, Colorado.  The orbiter payload will consist of six science    instruments and three new engineering payload elements listed as    follows:     Science Instruments    - HiRISE, High Resolution Imaging Science Experiment    - CRISM, Compact Reconnaissance Imaging Spectrometer for Mars    - MCS, Mars Climate Sounder    - MARCI, Mars Color Imager    - CTX, Context Camera    - SHARAD, Shallow (Subsurface) Radar     Engineering Payloads    - Electra UHF communications and navigation package    - Optical Navigation (Camera) Experiment    - Ka Band Telecommunication Experiment     To fulfill the mission science goals, seven scientific investigations    teams were selected by NASA.  Four teams (MARCI, MCS, HiRISE, and    CRISM) are led by Principal Investigators (PI), each responsible for    the provision and operation of a scientific instrument and the    analysis of its data.  The MARCI PI and Science Team also act to    provide and operate, as Team Leader (TL) and Team Members, the CTX    facility instrument that will provide context imaging for HiRISE and    CRISM, as well as acquire and analyze independent data in support of    the MRO scientific objectives.  The Italian Space Agency (ASI) will    provide a second facility instrument, SHARAD, for flight on MRO.  ASI    and NASA have both selected members of the SHARAD investigation team.    In addition to the instrument investigations, Gravity Science and    Atmospheric Structure Facility Investigation Teams will use data from    the spacecraft telecommunications and accelerometers, respectively, to    conduct scientific investigations.     The MRO shall accomplish its science objectives by conducting an    integrated program of three distinct observational modes:     - Daily global mapping and profiling observations    - Regional survey observations, and    - Globally distributed, targeted observations     These observation modes will be intermixed and often overlapping.    Some instruments have more than one observational mode.  In addition,    many targeted observations will involve nearly simultaneous,    coordinated observations by more than one instrument.  This program of    scientific observation will be carried out for one Mars year or more    in order to characterize the full seasonal variation of the Martian    climate and to target hundreds of globally distributed sites with high    potential for further scientific discovery.  Mission Success Criteria ------------------------     The following mission success criteria have been established for the    MRO Project. The mission success criteria are described and controlled    in the MRO Project Implementation Plan.     For Full Mission Success, the following criteria must be met:     - Operate the orbiter and all six (6) science instruments in the    Primary Science Orbit in targeting, survey and mapping modes, as    appropriate, over the one Mars year of the Primary Science Phase;    conduct the gravity and accelerometer investigations. Each science    instrument shall have capabilities that meet or exceed their    respective science instrument requirements.     - Return, over the one-Mars-year Primary Science Phase, representative    data sets for each instrument for a total science data volume return    of 26 Tbits or more. Included in the returned data volume shall be    information describing hundreds of globally distributed targets.     - Process, analyze, interpret, and release data in a timely manner,    including archival of acquired data and standard data products in the    PDS within 6 months of acquisition or as negotiated in the Science    Data Management Plan (JPL D22218).     - Conduct relay operations for U.S. spacecraft launched to Mars in the    2007 and 2009 opportunities.      For Minimum Mission Success, the following criteria must be met:     - Operate the orbiter and its science payload in targeting, survey and    mapping modes, as appropriate, in the Primary Science Orbit during the    one-Mars-year of the Primary Science Phase; conduct gravity and    accelerometer investigations. Science instruments shall have    capabilities that meet their respective science instrument    requirements.     - Return 10 Tbits of science data from HiRISE or CRISM or from their    combined operations, plus 5 Tbits of representative science data over    the one-Mars-year Primary Science Phase from at least 3 of the 4 other    instruments (CTX, MARCI, MCS, SHARAD); conduct gravity and    accelerometer investigations. Included in the returned data volumes    shall be information describing 100 or more globally distributed    targets.     - Process, analyze, interpret, and release data in a timely manner,    including archival of acquired data and standard data products in the    PDS.     - Conduct relay operations for U.S. spacecraft launched to Mars in the    2007 and 2009 opportunities.