Data Set Overview
      =================
   
      This data set includes the complete set of Clementine 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, spacecraft sequences of events, and data
      needed for relevant time conversions.
      
      This data set is contained on a single virtual volume, CLSP_1000,
      including data from all mission phases and covering from the day
      after launch, 1994-01-26, through the end of the mission,
      1994-05-07.
      

      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
      inter-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 Clementine 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. SPICELIB 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 MGS 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
      =========

      Two kinds of SPK files are provided in this archive: SPK files
      containing the spacecraft orbit and SPK files containing the Solar
      System ephemerides. Each of these kinds is briefly described
      below; more information is available in the file
      ``data/spk/spkinfo.txt''.
      
      This data set includes three spacecraft orbit SPK files, each
      from a different source: the Spacecraft Operations Team based at
      Naval Research Laboratory (NRL), the Clementine Gravity Team from
      Goddard Space Flight Center (GSFC), and the Solar System Dynamic
      group of the Jet Propulsion Laboratory (JPL). All three files
      provide trajectory covering most of the mission, with the
      coverage of the NRL SPK starting about three weeks earlier than
      the coverage of the other two files.

      Of the three SPKs the NRL file is the oldest; the trajectory
      provided in it was determined during mission. The GSFC SPK file
      contains trajectory determined after the end of the mission, in
      November 1994, as a part of the Clementine gravity data
      reduction. The JPL SPK provides the most recent of the three
      solutions, done in 2002 as a part of the Lunar gravity field
      improvement effort.

      Based on the coverage and history of these solutions NAIF
      recommends that, unless there are special circumstances, the JPL
      and NRL SPK files are used together in such way that the
      JPL SPK providing more a recent, and likely more accurate
      solution, is loaded last (to have higher priority) and the NRL file
      providing the longest coverage is loaded first (to have lower
      priority and be used only for the periods for which the JPL SPK
      does not provide coverage).

      The difference of the trajectories provided by the three
      spacecraft SPK files varies greatly throughout the mission,
      ranging from a few meters for some orbits to hundreds of meters
      to kilometers for the fits near the propulsive maneuvers.
      Appendix 1 of the ``data/spk/spkinfo.txt'' provides a summary of
      the down-track, radial, and out-of-plane components of the
      maximum difference for each pair of SPKs for each orbit.
      
      This data set also includes the orbit number file generated using
      the NAIF's ORBNUM utility program for the JPL SPK file for the
      orbital phases of the mission. This file is not SPICE kernel; for
      this reason it is provided in the ``extras/orbnum'' directory.
      For more information about the Clementine orbit number file, see
      the file ``extras/orbnum/orbinfo.txt''.
      
      This data set includes the DE414 SPK file, which the latest
      version of the JPL Planetary Ephemeris available at the time when
      this archive was created.

      
      CK Files
      ========
      
      This data set includes a single CK file providing the actual
      orientation of the Clementine spacecraft bus. This orientation is
      based on the data from the SPQ files generated and delivered to
      the project on a daily basis during mission operations by the
      Spacecraft Team, NRL and converted to CK files by Applied
      Coherent Technology (ACT) Corporation using the CPQ2CK program
      provided by NAIF. Unfortunately the specifics of production of
      the SPQ files had not been documented. It was suggested that the
      SPQ files contained the ``raw'' orientation estimated by the
      on-board Kalman filter using data from the star trackers and
      gyros, sent down in housekeeping telemetry and stored ``as is''
      in the SPQ files but it is not known for sure. It is also not
      clear whether the time tags attached to the ``raw'' attitude
      telemetry suffered from the same problems as the science image
      time tags and, if so, whether anything was done in the SPQ
      generation pipeline to correct them.

      More information about the Clementine CK files is available in
      the file ``data/ck/ckinfo.txt''.

      
      PCK Files
      =========
      
      Two PCK files are provided in this data set, one is a text PCK
      containing on the official IAU/IAG/COSPAR values accepted in
      2000, the other is a binary PCK containing high-accuracy
      orientation data for the lunar principal axes (PA) reference
      frame, from the JPL Solar System Dynamics Group's planetary
      ephemeris DE-403. Both files were the latest versions of the
      files of these types distributed by NAIF at the time when this
      archive was created. None of the PCK files used during mission
      operations and post-mission data analysis was included in this
      data set because they were superseded by the PCK files mentioned
      above.

      More information about the PCK files included in this data set is
      available in the file ``data/pck/pckinfo.txt''.
      

      FK Files
      ========
      
      This data set includes the Clementine mission FK file and a number
      of generic Lunar FK files. The Clementine FK file, created many
      years after the end of the mission in 2000, defines the frames
      for the Clementine spacecraft and its science instruments. The
      instrument frames defined in it incorporate mission-era mounting
      alignment data from the IK files included in this archive. The
      Lunar FK files, created in 2006-2007, define a number of lunar
      body-fixed frames associated high-accuracy lunar orientation data
      provided by the JPL Solar System Dynamics Group's planetary
      ephemerides and provide a mechanism to direct the SPICE system to
      associate either the lunar ``principal axis'' frame or the lunar
      ``mean Earth'' with the Moon.

      More information about the Clementine FK files is available in
      the file ``data/fk/fkinfo.txt''.
      
      
      IK Files
      ========
      
      This data set includes an IK file for each of the Clementine
      instruments -- HIRES, UVVIS, NIR, LWIR, LIDAR, CPT, and Star
      Trackers A and B. While these kernels were made at the time of
      archive preparation in 2007, they incorporate the instrument
      model parameters and mounting alignments that were derived at a
      much earlier time, during mission operations and/or immediate
      post mission data analysis in 1994. Although various printouts
      and hand notes indicate that the values provided in the IKs are
      probably the latest values derived by Thomas Duxbury, JPL at the
      end of the mission, NAIF was not able to either confirm this or
      to trace these value to an officially published or archived
      document. In addition to this mission-era data each of the IKs
      includes extensive comments and a GETFOV-type FOV definition;
      these were added when the IKs were updated at the time of the 
      archive preparation.

      More information about Clementine IK files is available in the
      file ``data/ik/ikinfo.txt''.
      
      
      SCLK Files
      ==========
      
      Only one SCLK kernel is included in this data set -- the SCLK
      kernel providing the nominal mapping of the Clementine on-board
      clock to ET. This file was created and used during mission
      operations. While this file is not adequate to support conversion
      of the actual Clementine on-board time tags it is still required
      to access data in the Clementine CK files.
 
      More information about the Clementine SCLK files is available in
      the file ``data/sclk/sclkinfo.txt''.

      
      LSK Files
      =========
      
      This data set includes the latest generic LSK kernel distributed
      by NAIF at the time when this archive was created. 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
      ========

      This data set includes a set of EK files containing the NAIF's
      Clementine image catalog. This catalog was created by NAIF in
      1994, after the end of the mission, to make the Clementine image
      attributes and derived geometry information available to the NAIF
      staff in the EK database format. It is included in this data set
      for the record and for convenience to the future users of the
      Clementine SPICE data who may desire to get the image times, file
      names, and other ``basic'' image attributes from a SPICE kernel
      rather than from the PDS index and/or label files. This catalog
      contains data for all 1,900,483 images archived in the
      CLEM1-L/E/Y-A/B/U/H/L/N-2-EDR-V1.0 data set.
      
      More information about the EK files is available in the file
      ``data/ek/ekinfo.txt''.


      Kernel Files Not Included In This Data Set
      ===========================================

      A number of kernel files used to process science data archived in
      PDS were either not included in this data set because they were
      superseded by the files provided in this archive or were included
      into the archive under different names. These files are:

        Type  Old file                 -->  Archived file
        ----  ----------------------  -----  ---------------------------
        SPK   SPKMERGE_940219_940504   (S)   clem_gsfc.bsp
              _CLEMV001b.bsp
        SPK   SPKMER09.BSP             (R)   clem_gsfc.bsp 
        SPK   SPKMERGE_9402191254_94   (R)   clem_gsfc.bsp
              05040324_CLEM.v002.bsp 
        SPK   clemdef.bsp              (R)   clem_nrl.bsp
        SPK   clem_ask020625.bsp       (R)   clem_jpl.bsp
        SPK   de245_1994.bsp           (S)   de414.bsp

        SCLK  dspse002.tsc             (R)   clem_nom.tsc

        CK    clem_2mn.bck             (S)   clem_act_ck3.bc
        CK    clem_5sc.bck             (S)   clem_act_ck3.bc
        CK    clem_act.bck             (S)   clem_act_ck3.bc
        CK    clemdef1.bck             (S)   clem_act_ck3.bc

        PCK   403s.bpc                 (S)   moon_pa_de403_1950_2198.bpc
        PCK   de245lib.bpc             (S)   moon_pa_de403_1950_2198.bpc
        PCK   pck00005.tpc             (S)   pck00008.tpc
        PCK   pck00006.tpc             (S)   pck00008.tpc

        FK    clem_v10.tf              (S)   clem_v20.tf

        IK    astar005.ti              (S)   clem_astar_006.ti
        IK    bstar005.ti              (S)   clem_bstar_006.ti
        IK    cpt001.ti                (S)   clem_cpt_002.ti
        IK    hires007.ti              (S)   clem_hires_008.ti
        IK    lidar004.ti              (S)   clem_lidar_005.ti
        IK    lwir007.ti               (S)   clem_lwir_008.ti
        IK    nir007.ti                (S)   clem_nir_009.ti
        IK    nir008.ti                (S)   clem_nir_009.ti
        IK    uvvis007.ti              (S)   clem_uvvis_008.ti

        EK    Apr15-May07.ek           (R)   clem_moon_940415_940507.bdb
        EK    Jan27-Mar12.ek           (R)   clem_moon_940127_940312.bdb
        EK    Mar12-Mar30.ek           (R)   clem_moon_940312_940330.bdb
        EK    Mar30-Apr15.ek           (R)   clem_moon_940330_940415.bdb
        EK    Sky.ek                   (R)   clem_sky_940201_940507.bdb

      where (R) stands for ``renamed to'' and (S) stands for ``superseded
      by''.