 
 
CLEMENTINE Spacecraft Orientation CK File
===========================================================================
 
     Created by Boris Semenov, NAIF/JPL, March 15, 2007 using data from the
     original complete CK file produced by ACT in 1994.
 
 
Orientation Data in the File
--------------------------------------------------------
 
     This file contains orientation and angular velocity data for the
     CLEMENTINE spacecraft frame, ``CLEM_SC_BUS'', relative to the
     ``J2000'' inertial frame. The NAIF ID code for the ``CLEM_SC_BUS''
     frame is -40000.
 
 
Status
--------------------------------------------------------
 
     This file contains reconstructed CLEMENTINE orientation distributed by
     the CLEMENTINE Spacecraft Team (SCT), Naval Research Laboratory (NRL)
     in the form of SPQ files. This CK file is intended for use in support
     of the CLEMENTINE experiment data processing and for archiving with
     the Planetary Data System (PDS).
 
 
Pedigree
--------------------------------------------------------
 
     This file contains the CLEMENTINE orientation data from the SPQ files
     generated and delivered to the project on a daily basis during mission
     operations by the SCT/NRL. The SPQ files were converted to Type 1 CK
     files by Applied Coherent Technology (ACT) Corporation using the
     CPQ2CK program provided by NAIF. At the end of the mission (summer
     1994) a single Type 1 CK file called ``clemdef1.bck'' covering the
     whole mission was made and distributed among the project SPICE
     community. At the time of the CLEMENTINE PDS SPICE data set
     preparation (spring 2007) the Type 1 CK segments from ``clemdef1.bck''
     were first converted to Type 3 CK segments using the CKSPANIT utility
     program and then merged together to eliminate the segment boundary
     gaps using the CKSMRG utility program to produce this file. No
     modifications of the orientation, angular rates or time tags occurred
     in the conversion process. Finally the comment area of this file was
     filled with descriptive comments.
 
     Unfortunately the specifics of production of the SPQ files that were
     the ultimate source of the data stored in this file 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.
 
 
Approximate Time Coverage
--------------------------------------------------------
 
     This file covers the following time period:
 
               Begin UTC                End UTC
        ------------------------ ------------------------
        1994-FEB-01 10:37:48.671 1994-MAY-26 02:42:11.378
 
     This file is a type 3 CK file which provides linear interpolation
     between orientation data points stored in the file segments. Such
     interpolation is not applied to the whole coverage of the file but
     only inside intervals where enough orientation data are available and
     orientation data points are close to each other in time for such
     interpolation to make sense.
 
     While spacing between the data points stored in this file varies, the
     majority of the points are 5, 10, 20, or 40 seconds apart, with over
     95% of the points being just 5 seconds apart. To maximize the coverage
     provided by the file the interpolation intervals for the file segments
     are set in such way that interpolation is allowed between all points
     that are less than 65 seconds apart. For all requests for data falling
     between two adjacent data points separated by more than 65 seconds the
     SPICELIB routines will not return pointing. Note that if needed the
     interpolation intervals in this CK can be modified using a utility
     program named CKSPANIT available from NAIF.
 
     The complete list of valid interpolation intervals can be generated by
     running CKBREIF utility program with ``-dump'' option.
 
 
Related Kernels
--------------------------------------------------------
 
     This file was created and should be used with LSK file
     ``naif0008.tls'' and CLEMENTINE SCLK file ``clem_nom.tsc''.
 
 
Contacts
--------------------------------------------------------
 
     If you have questions regarding this data contact
 
        Boris V. Semenov
        (818)-354-8136,
        Boris.Semenov@jpl.nasa.gov
 
 
