                                                                              
  VEX IK Files                                                                
  ============                                                                
                                                                              
  This "aareadme.txt" file describes the contents of the kernels/ik           
  directory of the VEX SPICE data server. It also provides the file naming    
  conventions used for the VEX IK kernels, and it provides identification     
  of the most current version of each kind of IK file.                        
                                                                              
  All these IK files are produced manually with the information supplied by   
  Venus Express teams describing the science instruments.                     
                                                                              
  The most detailed description of the data in an IK file is provided in      
  metadata included inside the description area of the file. This information 
  can be viewed using any text editor program.                                
                                                                              
  At least a basic knowledge of the SPICE system is needed in order to use    
  these kernels. The SPICE toolkit provides versions in Fortran (SPICELIB), C 
  (CSPICE), IDL (icy) and Matlab (mice), and the user can choose any one that 
  suits him/her.                                                              
                                                                              
  The SPICELIB routine FURNSH, CSPICE function furnsh_c, icy and mice routine 
  cspice_furnsh load a kernel file into the kernel pool as shown below.       
                                                                              
      CALL FURNSH ( 'kernel_name' )                                           
      furnsh_c    ( "kernel_name" );                                          
      cspice_furnsh, 'kernel_name'                                            
      cspice_furnsh( 'kernel_name' )                                          
                                                                              
  In the case when two or more files contain data overlapping in time for a   
  given object, for binary kernels, the file loaded last takes precedence.    
                                                                              
  If two (or more) text kernels assign value(s) using the '=' operator to     
  identical keywords, the data value(s) associated with the last loaded       
  occurrence of the keyword are used -all earlier values have been replaced   
  with the last loaded value(s).                                              
                                                                              
  All IK files (*.TI) contained in this directory are unix text files. These  
  may be used in a non-compatible text environment by using the ASCII mode of 
  FTP to port the files.                                                      
                                                                              
  Contact                                                                     
                                                                              
	ESA SPICE Service       esa_spice@sciops.esa.int
                                                                              
  , or                                                                        
                                                                              
    Jose Luis Vazquez    jlvazquez@sciops.esa.int                             
                                                                              
  if you have any questions.                                                  
                                                                              
                                                                              
                                                                              
Venus Express IK Directory Structure                                          
===================================                                           
                                                                              
                                                                              
  aareadme.txt            This file                                           
                                                                              
  former_versions         Subdirectory that contains obsolete
                          versions of the IK files that have
                          been updated in the Current IK
                          Kernel Set.                                         
                                                                              
  VEX_ASPERA4_Vvv.TI      ASPERA-4 Instrument Kernel, containing
                          geometry parameters.
                                                                              
  VEX_PFS_Vvv.TI          PFS Instrument Kernel, containing geometry,
                          optics, detector and FOV parameters.

  VEX_SOIR_Vvv.TI         SPICAV-SOIR Instrument Kernel, containing
                          geometry parameters for the instrument.

  VEX_SPICAV_Vvv.TI       SPICAV Instrument Kernel, containing
                          geometry parameters for the instrument UV
                          and IR channels.
                                                                              
  VEX_VIRTIS_Vvv.TI       VIRTIS instrument kernel, containing geometry,      
                          optics, detector and FOV parameters.                
                                                                              
  VEX_VMC_Vvv.TI          VMC instrument kernel, containing geometry,
                          optics, detector and FOV parameters.
                                                                              
                                                                              
-------------------                                                           
                                                                              
        This file was last modified on March 17th, 2009. (J. Vazquez)         
