=============================================================================
MEX CK Files
=============================================================================

  Last update:  10 NOV 2004  

  This "aareadme.txt" file describes the contents of the KERNELS/CK
  directory of the MEX SPICE data server.  It also provides the file 
  naming conventions used for the MEX CK kernels, and it provides
  identification of the most current version of each kind of CK file.

  All these CK files are produced by an automated system located at ESTEC, 
  operated by the MEX Project Science Team (PST). We have chosen to use the
  ESOC naming convention for CK files, which are converted from ESOC's DDID
  Attitude files. Although this convention doesn't seem very descriptive and
  holds some redundant information, it could be useful to use the same name
  style for the sake of consistency. Also, data handling performed by the PST
  automated system will be easier and faster.

  There is an exception to the above mentioned. RECONSTITUTED data in ESOC's
  DDID format are converted to CK files using the Auxiliary Data Conversion
  System (ADCS) tool at ESTEC. Then the new CK files are appended to the
  existing "Reconstituted Data kernel file". The comment area of this
  kernel is updated every time new data are appended. This process is
  executed manually.

  The contents and time span covered by any CK file may be easily determined
  using the "brief" utility program available in all copies of the
  SPICE Toolkit. Examples of usage:  
     %ckbrief  <ck_file_name> <sclk_file_name> <lsk_file_name>

  This utility requires additionally a sclk file and a lsk file; use the 
  latest versions of these files.

  Descriptive information about how/why/when an CK file was created is 
  usually available in the "comment area" of the file. This may be viewed
  using the "commnt" utility program available in all copies of the SPICE
  Toolkit. Use the "-r" option to read the comments. Example:
    %commnt -r <ck_file_name>

  All binary CK files (*.BC) contained in this directory are unix binary
  files. These may be used as is (without format conversion) in a non-unix
  environment when using any recent version of the SPICE Toolkit (Version
  N0052 or later).  [Ref 3b]

  Contact Jorge Diaz del Rio (jdiaz@rssd.esa.int) or Joe Zender 
  (Joe.Zender@esa.int) if you have any questions.


=============================================================================
References
=============================================================================
    1. Data Delivery Interface Document (DDID)       Appendix H - FD 
       products Issue 1.3 (MEX-ESC-IF-5003)

    2. CK Required Reading. NAIF Document No. 174.08  05 Sep 2002

    3. Selected SPICE Tutorials from the NAIF server:  
ftp://naif.jpl.nasa.gov/pub/naif/toolkit_docs/Tutorials/office/individual_docs

       a) CK Tutorial                 15_ck.ppt
       b) Porting Kernels Tutorial    09_porting_kernels.ppt

    4. NAIF IDs Required Reading. NAIF Document No. 219.12  30 Jul 2003

  
=============================================================================
Mars Express CK Directory Structure
=============================================================================
 aareadme.txt            Text file describing the directory structure, 
                         the naming conventions for the CKs, and the current
                         version(s) of each CK type.

 former_versions         Subdirectory that contains obsolete versions of the 
                         CK files that have been updated in the Current CK
                         Kernels Set.




=============================================================================
MEX Spacecraft CK Naming Covention               ffff_yYYMMDDhhmmss_vvvvv.ee
=============================================================================


          token           description
          ------------    --------------------------------------------------
          ffff            Source Product Type Identifier: 
                             ATNM -- Predicted S/C attitude
       		      
          y               Data Type Identifier                      
       	       	             P -- Predicted data
          YYMMDDhhmmss    Coverage start time of the data contained
	                  in the ATNM file.
          vvvv            version number
          ee              NAIF File Name Extension  -- "BC"  (binary C kernel)


=============================================================================
MEX "Planning CK" Naming Covention               ffff_PTRvvvvv_YYMMDD_xxx.ee
=============================================================================


          token           description
          ------------    --------------------------------------------------
          ffff            Source Product Type Identifier: 
                             ATNM -- Predicted S/C attitude
       		      
          vvvvv           PTR version number
          YYMMDD          Coverage start time of the data contained
	                  in the ATNM file.
          xxx             file version number
          ee              NAIF File Name Extension  -- "BC"  (binary C kernel)


=============================================================================
Current CK Kernels Set
=============================================================================

 Name                              Comments
 --------------------------------  -------------------------------------
 ATNM_PYYMMDDhhmmss_xxxxx.BC       Contains Mars Express predicted attitude
                                   information covering the time span
                                   starting at the date YYMMDDhhmmss. This
                                   attitude information corresponds to the
                                   ESOC attitude file named:
                                   ATNM_FDLMMA_DAPYYMMDDhhmmss_xxxxx.MEX
                                   where xxxxx designates the version number.

 ATNM_PTRvvvvv_YYMMDD_xxx.BC       Contains Mars Express predicted attitude
                                   information covering the time span 
                                   starting at the date YYMMDD. This attitude
                                   information corresponds to the PTR file
                                   version vvvvv delivered from POS to ESOC
                                   and it is intended for the Teams to check
                                   the pointings. The final attitude file is
                                   fixed after iterating the PTR and it may
                                   differ from this "planning C-Kernel".

 ATNM_RECONSTITUTED_xxxxx.BC       Contains Mars Express RECONSTITUTED
                                   attitude information. This attitude 
                                   information corresponds to all 
                                   reconstituted attitude files delivered from
                                   ESOC to PST. This file is updated every 
                                   time new reconstituted data are available.
                                   The file contains gaps between data 
                                   segments. Extensive documentation
                                   specifying valid interpolation intervals
                                   (periods with no data gaps) is provided in
                                   the comment area. Please refer to text
                                   above for information about using the 
                                   COMMNT utility.