 
 
CLEMENTINE Spacecraft Trajectory SPK file, JPL SSD Solution
===========================================================================
 
     Created by Alex Konopliv, Solar System Dynamics group, JPL, June 25,
     2002. Comments added by Boris Semenov, NAIF/JPL, March 8, 2007.
 
 
Objects in the Ephemeris
--------------------------------------------------------
 
     This file contains ephemeris data for the CLEMENTINE spacecraft (NAIF
     ID -40) with respect to the Moon in the J2000 inertial reference
     frame.
 
 
Approximate Time Coverage
--------------------------------------------------------
 
     This file covers the following time period:
 
        Start of Interval (ET)      End of Interval (ET)
        ------------------------    ------------------------
        1994 FEB 19 13:01:00.185    1994 MAY 04 04:31:00.185
 
 
Status
--------------------------------------------------------
 
     This files contains CLEMENTINE trajectory determined by the Solar
     System Dynamics group, JPL as part of Lunar gravity field improvement
     work and intended for use in support of the CLEMENTINE experiment data
     processing and for archiving with the Planetary Data System (PDS).
 
 
Pedigree
--------------------------------------------------------
 
     This file was created by Alex Konopliv, Solar System Dynamics group,
     JPL as part of 2002 Lunar gravity field improvement effort. The
     original name of this file was ``clem_ask020625.bsp''.
 
 
Segment Boundary Discontinuities
--------------------------------------------------------
 
     This SPK file contains a large number of SPK segments that came from
     original individual SPK files. Although, each segment provides
     continuous trajectory within the interval that it covers, in general a
     position and velocity discontinuity exists at the boundary of the
     segment and the segments whose coverage immediately precede and follow
     it. The times and magnitudes of these discontinuities are provided in
     the Appendix 1 of these comments.
 
 
Contacts
--------------------------------------------------------
 
     If you have questions regarding this data contact
 
        Boris V. Semenov
        (818)-354-8136,
        Boris.Semenov@jpl.nasa.gov
 
 
Appendix 1: Segment Boundary Discontinuity Summary
--------------------------------------------------------
 
     This SPK file contains a large number of SPK segments that came from
     original individual SPK files. Although, each segment provides
     continuous trajectory within the interval that it covers, in general a
     position and velocity discontinuity exists at the boundary of the
     segment and the segments whose coverage immediately precede and follow
     it. The times and magnitudes of these discontinuities are provided in
     the table included in this Appendix.
 
     The top portion of the table contains the name of this SPK file. All
     descriptive lines in the top portion of the file start with the ``#''
     character to allow direct plotting of the data in the freeware
     ``gnuplot'' application.
 
     The table consists of 4 columns. The first column contains the UTC
     time of that segment boundary. The last three columns (2..4) contain
     view coordinate frame components -- ``down track'' (this direction is
     parallel to the velocity vector), ``normal to plane'' (this direction
     is computed as cross product of position vector by velocity vector)
     and ``in plane'' (this direction is computed as a cross product of
     ``down track'' by ``normal to plane'') -- of the difference between
     the state vectors computed at that UTC time defining segment boundary
     at which a discontinuity exists.
 
     The pairs of segments and discontinuity times are determined using an
     algorithm that emulates the standard SPK loading priority -- ``last
     loaded segment takes precedence''. Therefore, the discontinuities
     summarized in the file are those which a user reading file would
     actually see.
 
     The difference components in the view coordinate frame were computed
     for each discontinuity using the following algorithm:
 
         --   A single state was computed from each pair of segment the
              J2000 frame at the time of discontinuity.
 
         --   For this pair of states, a position difference vector was
              computed by subtracting the state computed from the segment
              with higher priority from the state computed from segment
              with lower priority. Then, a frame transformation matrix
              rotating these difference vectors from J2000 to the view
              coordinate frame defined by the state obtained from the
              higher priority segment was computed, and the position
              difference vector was rotated to the view frame coordinates
              using this matrix.
 
     The segment boundary discontinuities for this file are:
 
        #
        # Summary of discontinuities at segment boundaries for
        # SPK file clem_jpl.bsp:
        #
        #  BOUNDARY TIME (UTC)   DOWNTRK INPLANE  NORMAL
        #----------------------- ------- ------- -------
        1994-02-20T12:40:00.000   0.241  -0.023   0.003
        1994-02-21T12:15:00.000  11.926  -0.852   0.040
        1994-02-22T12:15:00.000   0.133   0.679  -0.002
        1994-02-25T12:00:00.000   0.065  -0.020   0.103
        1994-02-28T12:00:00.000   0.013   0.010   0.017
        1994-03-03T12:00:00.000  -0.034   0.014   0.027
        1994-03-06T12:00:00.000  -0.012  -0.007  -0.001
        1994-03-09T12:00:00.000   0.010  -0.005   0.009
        1994-03-11T14:35:00.000  -0.151  -2.985  -0.017
        1994-03-14T12:00:00.000   0.064  -0.003  -0.021
        1994-03-17T12:00:00.000  -0.042  -0.017  -0.015
        1994-03-20T12:00:00.000  -0.012   0.006   0.000
        1994-03-23T12:00:00.000  -0.005  -0.003   0.001
        1994-03-26T02:20:00.000 -10.383   2.637  -2.850
        1994-03-26T12:40:00.000  10.315   0.528   3.323
        1994-03-27T18:30:00.000   0.002  -0.005   0.007
        1994-03-30T12:00:00.000   0.006  -0.000   0.003
        1994-04-02T12:00:00.000   0.081   0.018   0.004
        1994-04-05T12:00:00.000  -0.046  -0.018   0.043
        1994-04-08T12:00:00.000   0.007   0.001   0.008
        1994-04-11T06:30:00.000  -0.008   0.609  -0.057
        1994-04-14T06:00:00.000  -0.013   0.002   0.007
        1994-04-17T06:00:00.000   0.036   0.002   0.002
        1994-04-20T06:00:00.000   0.038  -0.002   0.004
        1994-04-23T06:00:00.000  -0.006  -0.000  -0.000
        1994-04-26T06:00:00.000  -0.016  -0.002  -0.007
        1994-04-29T06:00:00.000   0.207  -0.038   0.018
        1994-05-02T06:00:00.000  -0.056  -0.040   0.037
 
 
