Data Set Overview
      =================
   
      This data set includes the complete set of Mars Reconnaissance
      Orbiter SPICE data files (``kernel files''), which can be
      accessed using SPICE software. The SPICE data contains geometric
      and other ancillary information needed to recover the full value
      of science instrument data. In particular SPICE kernels provide
      spacecraft and planetary ephemerides, instrument mounting
      alignments, spacecraft orientation, and data needed for relevant 
      time conversions.
      
      This data set is contained on a single virtual volume,
      MROSP_1000, including data from all mission phases and covering
      from launch, 2005-08-12T12:40:00, through the end time of the
      latest spacecraft trajectory file supplied in the data set. Until
      the end of the spacecraft lifespan this data set is accumulating
      with new data added approximately every three to six months.


      Data Types (SPICE kernel types)
      ===============================
   
      SPK kernels contain ephemerides for spacecraft, planets,
      satellites, comets and asteroids as well as for moving or fixed
      spacecraft and instrument structures. They provide position and
      velocity, given in a Cartesian reference frame. SPK files are
      located under the ``data/spk'' directory of this data set.
      
      PCK kernels contain certain physical, dynamical and cartographic
      constants for target bodies, such as size and shape
      specifications, and orientation of the spin axis and prime
      meridian. PCK files are located under the ``data/pck'' directory
      of this data set.

      IK kernels (Instrument description kernels) give descriptive and
      operational data peculiar to a particular scientific instrument,
      such as internal timing relative to the spacecraft clock and
      field-of-view model parameters. IK files are located under the
      ``data/ik'' directory of this data set.

      CK kernels describe pointing, containing a transformation
      traditionally called the C-matrix which is used to determine
      time-tagged pointing (orientation) angles for a spacecraft
      structure upon which science instruments are mounted. CK files
      are located under the ``data/ck'' directory of this data set.

      EK (Events) kernels are derived from the integrated sequence of
      events used to produce actual spacecraft commands. EK files are
      located under the ``data/ek'' directory of this data set.

      LSK (Leapseconds) kernels contain the leapseconds and the values
      of other constants required to perform a transformation between
      Universal Time Coordinated (UTC) and Ephemeris time (ET). LSK
      files are located under the ``data/lsk'' directory of this data
      set.

      SCLK (Spacecraft Clock) kernels contain on-board clock
      calibration data required to perform a mapping between Ephemeris
      time (ET) and spacecraft on-board time (SCLK.) SCLK files are
      located under the ``data/sclk'' directory of this data set.

      FK (Frame Definitions) kernels contain information required to
      define reference frames, sources of frame orientation data and
      connections between these frames and other frames supported
      within the SPICE system. This includes mounting alignment
      information for each instrument. FK files are located under the
      ``data/fk'' directory of this data set.

            
      Kernel File Details
      ===================
      
      A brief overview of the different types of MRO kernels included
      in this data set is provided in the CONFIDENCE_LEVEL_NOTE section
      of this file while details specific to individual files are found
      in the ``*info.txt'' files in the corresponding data directory.
      The most detailed description of the data in each file is
      provided in metadata included inside the file -- in the
      description area of text kernels or in the comment area of binary
      kernels.
   
   
      Software
      ========
   
      The SPICE Toolkit contains software modules needed to read SPICE
      kernel files. SPICE software is highly documented via internal
      headers. Additional documentation is available in separate ASCII
      text files called Required Reading files. For example, the S- and
      P- Kernel (SPK) Required Reading File, named SPK.REQ, describes
      use of the SPK kernel file readers and contains sample programs.
 
      The latest SPICE Toolkit for a variety of computer platforms such
      as PC, Mac, SUN, etc. is available at the NAIF Node of PDS
      electronically (via anonymous FTP and WWW servers). Refer to
      information in ``software/softinfo.txt'' for details regarding
      obtaining this software. Each version of the Toolkit is also
      archived at the NASA National Space Science Data Center.
   

      Loading Kernel Files into a SPICE-based Application
      ===================================================
 
      The easiest way to make data from a collection of SPICE kernels
      available to a SPICE-based application is to list these kernels
      in a meta-kernel and load it into the program using the high
      level SPICE data loader routine FURNSH. This data set provides
      such meta-kernel(s) under the ``extras/mk'' directory. For more
      information about the MRO meta-kernel(s), see the file
      ``extras/mk/mkinfo.txt''.

This data set contains SPICE kernel files created during mission
      operations and after mission data reconstruction and analysis.
      Some general information about this collection follows here, but
      the prospective user is also referred to extensive descriptions
      about each file that are stored inside each kernel file. These
      metadata provide detailed information regarding the information
      source from which the data were derived, the type of processing
      applied to the source data, applicability of the data, etc.
      Metadata are located in the ``comment area'' for binary kernel
      types (SPK, CK, ESQ), accessible using either the COMMNT or
      SPACIT utility program found in the NAIF Toolkit. Metadata are
      located after ``\begintext'' markers within the text kernel types
      (PCK, IK, FK, LSK, SCLK, MK), accessible by using any available
      text file display tool such as a word processor, text editor, or
      the unix ``more'' or ``cat'' commands.
 
      Where there are questions about data accuracy or ``confidence''
      not addressed herein the reader is invited to contact the NAIF
      node of the Planetary Data System for possible further
      information.
      
      
      SPK Files
      =========

      Three kinds of SPK files are provided in this archive: SPK files
      for the spacecraft orbit, SPK files for the Solar System planets
      and Martian system satellites, and SPK files for the relative
      locations of selected spacecraft structures. Each of these kinds
      is briefly described below; more information is available in the
      file ``data/spk/spkinfo.txt''.
 
      Two sets of the MRO spacecraft orbit SPK files are included in 
      this data set. 

      The first set of the spacecraft orbit SPK files contains the
      reconstructed spacecraft trajectory determined by the MRO
      Navigation (NAV) Team, JPL. Each of these SPK files covering the
      whole or a part of a particular mission phase was made by merging
      together numerous shorter duration individual files officially
      delivered by the NAV team to the project. The component files
      used to make a merged product can be discerned by reading the
      descriptive information (metadata) found in the comment area of
      each file. The accuracy of the spacecraft trajectory provided by
      these files for the orbital phases of the mission was informally
      reported by the NAV team to be better than than a few meters.
 
      The second set of the spacecraft orbit SPK files contains the
      reconstructed spacecraft trajectory determined by the Solar
      System Dynamics (SSD) Group, JPL. These SPK files are available
      only for the post-aerobraking phases of the mission (PSP, Relay).
      They were generated in the process of the MRO gravity experiment
      data reduction using the 95th degree and order MRO95A gravity
      solution, which included entire MGS mission tracking data set and
      Mars Odyssey and MRO tracking data up to the orbit solution date.
      The data arcs for the orbits in these files are slightly longer
      than 4 days in length. They were extended so that Doppler data
      was contained at the beginning and end of the orbit solutions.
      The orbit overlap errors using a 2-hr overlap were on average 0.5
      meters for along the velocity vector and normal to the orbit
      plane, and 5 cm for the radial component. The normal error
      increased to about 50 meters during the edge-on geometry phase at
      the end of June 2007.
 
      This data set also includes the orbit number files generated
      during the mission using the NAIF's ORBNUM utility program for
      each of the NAV spacecraft trajectory SPK files for the orbital
      phases of the mission. These files are not SPICE kernels; for
      this reason they are provided in the ``extras/orbnum'' directory.
      For more information about the MRO orbit number files, see the
      file ``extras/orbnum/orbinfo.txt''.
 
      The DE410 planetary ephemeris SPK file included in this data set
      contains ephemeris data for the Solar System planet barycenters,
      Sun, Mercury, Venus, Earth, Moon, and Mars. This version of
      ephemerides was officially used by the project during mission
      operations. The internal comments included this SPK file provide
      detailed accuracy information.
 
      The MAR063 Martian satellite ephemeris SPK file provided in this
      data set contains ephemeris data for Phobos, Deimos, Earth and
      the Sun. Formal one-sigma accuracy information for Phobos and
      Deimos are reported as follows:
 
         Body         Downtrack      Crosstrack      Radial
                     Uncertainty     Uncertainty   Uncertainty
         ------      -----------     -----------   -----------
         Phobos          5 km           2 km          2 km
         Deimos         10 km           3 km          3 km
      
      The MRO structures SPK file included in this archive provides
      relative locations of the High Gain Antenna (HGA) and Solar Array
      (SA) components. The data included in the file are based of the
      dimensions from the spacecraft engineering drawings.
      
      
      CK Files
      ========
      
      Five kinds of C-kernel files are provided in this archive: the
      spacecraft bus (SC) orientation CKs (reconstructed and
      predicted), the solar arrays (SA) orientation CKs (reconstructed
      and predicted), the high gain antenna (HGA) orientation CKs
      (reconstructed and predicted), the CRISM instrument orientation
      CKs (reconstructed only), and the MCS instrument orientation CKs
      (reconstructed only).
 
      The SC, SA, and HGA reconstructed CK files were produced from
      engineering telemetry downlinked from the spacecraft while the
      SC, SA, and HGA predicted CK files were produced from spacecraft
      orientation and articulation data modeled by the AtArPS program
      ran by the MRO Spacecraft Team, LMA. While the coverage provided
      by the reconstructed CK is fairly complete, they have occasional
      small gaps. The predicted CKs included in this data set are
      intended to be used to fill these gaps with nominal orientation
      by loading these predicted files simultaneously with (but with
      lower priority than) the reconstructed files. All of these CKs
      contain data tagged with encoded SCLKs computed using the clock
      with ID -74.
 
      The CRISM CK files providing orientation for the CRISM instrument
      were produced by the CRISM team using the gimbal angle data from
      the instrument housekeeping telemetry. These files were used by
      the CRISM team to process CRISM science data. The CRISM CKs
      contain data tagged with encoded SCLKs computed using the clock
      with ID -74999.
 
      The MCS CK files providing orientation for the MCS instrument
      were produced by the MCS team using the gimbal angle data from
      the instrument housekeeping telemetry. These files were used by
      the MCS team to process MCS science data. These CKs contain data
      tagged with encoded SCLKs computed using the clock with ID -74.
 
      Currently no formal accuracy estimates are available for any of
      these CKs.
 
      More information about MRO CK files is available in the file
      ``data/ck/ckinfo.txt''.

      
      PCK Files
      =========
      
      PCK files provide size, shape and orientation data for ``target''
      bodies such as Mars, Phobos and Deimos. A description of these
      data items and reference to their source is provided inside the
      PCK file, which is a simple text file that can be viewed using
      any word processor, text editor or text display utility.
 
      The only PCK file included in this data set is based on the
      IAU/IAG/COSPAR values accepted in 2000. This PCK has been used by
      the MRO project during operations.
 
      More information about the PCK files included in this data set is
      available in the file ``data/pck/pckinfo.txt''.
      

      FK Files
      ========
      
      Frames kernel files provide specifications for how one reference
      frame is defined relative to another frame. The MRO FK provided
      in this data set contains the complete set of frame definitions
      for the spacecraft, its structures such as solar array and
      antennas, and all of its science instruments. Meta information
      provided in the comments included in this file consists of the
      frame definitions, description of the frame relationships, source
      of and accuracy of the mounting alignment information, etc.
 
      More information about the MRO FK files is available in the file
      ``data/fk/fkinfo.txt''.
      
      
      IK Files
      ========
      
      Instrument kernel files provide specifications for geometric
      parameters and--where applicable--field-of-view size, shape and
      orientation for the named instruments. Metadata describing these
      estimates are provided in each IK file included in this archive.
      Parameter values were determined from pre-launch measurements,
      instrument parameters specification documents, and in some cases
      from analysis of in-flight calibration data. The accuracy
      estimates for these data vary from instrument to instrument and,
      where available, are included in the IK internal comments.
 
      This data set includes IK files for six MRO instruments -- CRISM,
      CTX, HIRISE, MCS, MARCI, and ONC. Because the sets of geometric
      parameters included in the IKs vary from instrument to instrument
      users are encouraged to carefully examine the IKs before using
      them.

      The IK for SHARAD will be added to the data set in a later
      release.
 
      More information about MRO IK files is available in the file
      ``data/ik/ikinfo.txt''.

            
      SCLK Files
      ==========
      
      Spacecraft Clock kernel files provide a tabulation of data needed
      for converting time measurements between ephemeris time (ET) and
      spacecraft clock time (SCLK). The MRO SPICE SCLK files were made
      from similar files--SCLK/SCET files, or SCLKvSCET file--produced
      by another mission entity. Each newly made SCLK file fully
      replaces the previous SCLK file.
 
      For MRO the time correlation accuracy provided in SCLK/SCET files
      is informally reported by the Lockheed Martin spacecraft team to
      be better than 10 milliseconds. (NAIF has not attempted to obtain
      or produce an independent corroboration of these LMA estimates.)
      The SPICE SCLK file has essentially the same accuracy as the
      SCLK/SCET file.
 
      Each of the MRO SCLK files incorporates two time correlation data
      sets -- one for the MRO on-board clock tags presented in the
      ``standard'' format and the other for the tags in the ``high
      precision'' format.
 
      ``Standard'' MRO on-board clock tags are derived from 5-byte tags
      present in majority of the spacecraft and instrument telemetry
      and utilizing only the last of five bytes for fractional seconds.
      This results in one SCLK tick being equal to 1/256 of a second.
      The ID of this clock is -74, the same as of the MRO spacecraft.
 
      ``High precision'' MRO on-board clock tags are derived from
      6-byte tags present in some of the spacecraft and instrument
      telemetry and utilizing the last two of six bytes for fractional
      seconds. This results in one SCLK tick being equal to 1/65536 of
      a seconds. The ID of this clock is -74999.
 
      SPICE software does not prohibit an SCLK file from being used for
      time conversions occurring for ``future times'' (or more
      accurately, for epochs that occur later than the epoch of the
      last telemetry data used in producing the last correlation
      coefficients found in the SCLK file). Such ``predict'' time
      conversions are likely to be inaccurate (changed somewhat) once
      the epoch of interest has been passed.
 
      More information about the MRO SCLK files is available in the
      file ``data/sclk/sclkinfo.txt''.

      
      LSK Files
      =========
      
      Leapseconds kernel files provide a tabulation of ``leapseconds''
      and some other terms used in converting time measurements between
      ephemeris time (ET) and Universal Time (UTC). ``Spacecraft Event
      Time'' (SCET) is the commonly used name for UTC events measured
      at the spacecraft.
 
      Metadata describing how the LSK data are obtained or computed is
      contained inside the LSK text file. The time conversion provided
      by SPICE LSK files is accurate to approximately 0.000030 seconds.
 
      More information about the LSK files is available in the file
      ``data/lsk/lskinfo.txt''.
      
      
      EK Files
      ========
      
      The MRO project did not produce any EK files; therefore, no EKs
      are included in this data set.