Mission Objectives Overview  ===========================    The Mars Science Laboratory began surface operations soon after the    Curiosity rover landed. The overall scientific goal of the mission has    been to quantitatively assess past and present habitable environments at    Gale crater.  The MSL rover carries ten scientific instruments and a    sample acquisition, processing, and distribution system.  The various    science payload elements are used as an integrated suite to characterize    the local geology, study potential sampling targets with remote and in    situ measurements; to acquire samples of rock, soil, and atmosphere and    analyze them in onboard analytical instruments; and to observe the    environment around the rover. An overview of the science mission is    provided in [GROTZINGERETAL2012].    The MSL rover was sent to investigate Gale crater, which shows clear    evidence for ancient aqueous processes based on orbital data and to    undertake the search for past and present habitable environments.    Assessment of present habitability requires an evaluation of the    characteristics of the environment and the processes that influence it    from microscopic to regional scales and a comparison of those    characteristics with what is known about the capacity of life, as we know    it, to exist in such environments.  Determination of past habitability has    the added requirement of inferring environments and processes in the past    from observation in the present.  Such assessments require the integration    of a wide variety of chemical, physical, and geological observations.    MSL is not a life detection mission and is not designed to detect extant    vital processes that would betray present-day microbial metabolism.  Nor    does it have the ability to image microorganisms or their fossil    equivalents.  MSL does have, however, the capability to detect complex    organic molecules in rocks and soils.  If present, these might be of    biological origin, but could also reflect the influx of carbonaceous    meteorites.  More indirectly, MSL has the analytical capability to probe    other less unique biosignatures, specifically, the isotopic composition of    inorganic and organic carbon in rocks and soils, particular elemental and    mineralogical concentrations and abundances, and the attributes of unusual    rock textures.  The main challenge in establishment of a biosignature is    finding patterns, either chemical or textural, that are not easily    explained by physical processes.  MSL is also be able to evaluate the    concentration and isotopic composition of potentially biogenic atmospheric    gases such as methane, which has been detected in the modern atmosphere.    But compared to the current and past missions that have all been targeted    to find evidence for past or present water, the task of searching for    habitable environments is significantly more challenging (e.g.,    [GROTZINGER2009]).  Primarily, this is because the degree to which organic    carbon would be preserved on the Martian surface - even if it were    produced in abundance - is unknown.    The MSL prime mission had eight science objectives in order to address the    overall habitability assessment goal: (1) Characterize geological    features, contributing to deciphering geological history and the processes    that have modified rocks and regolith, including the role of water; (2)    Determine the mineralogy and chemical composition of surface and near-    surface materials (including an inventory of elements such as C, H, N, O,    P, S, etc., known to be the building blocks for life); (3) Determine    energy sources that could be used to sustain biological processes; (4)    Characterize organic compounds and potential biomarkers in representative    regolith, rocks, and ices; (5) Determine stable isotopic and noble gas    composition of the present-day atmosphere and of ancient H2O and CO2    preserved in hydrated minerals (italicized wording is new; added for    clarification); (6) Identify potential biosignatures (chemical, textural,    isotopic) in rocks and regolith; (7) Characterize the broad spectrum of    surface radiation, including galactic cosmic radiation, solar particle    events, and secondary neutrons; and (8) Characterize the local    environment, including basic meteorology, the state and cycling of water    and CO2, and the near-surface distribution of hydrogen.    For the first extended mission, the original eight prime mission    objectives were retained and two new ones were added: (9) Identify and    quantitatively assess 'taphonomic windows' for organic carbon (subset of    habitable environments also capable of preserving organic compounds,    through exposure age dating and refined models for primary facies    distributions and diagenesis) and (10) Explore and characterize major    environmental transitions recorded in the geology of the foothills of Mt.    Sharp and adjacent plains.