General Information About SPICE FRAMES Kernels                                
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   In the SPICE system, the FRAMES kernel contains a set of information       
   required to define various reference frames specific to a particular       
   mission, sources of orientation and origin location information for        
   these frames, and inter-connections between these frames and other,        
   generic frames supported within the SPICE system.                          
                                                                              
   The frame definitions information contained in the file can be             
   utilised by a collection of subroutines to provide correct                 
   interpretation for the SPICE data from SP- and C-kernels. These            
   subroutines are part of the SPICE library, the principal component         
   of the SPICE Toolkit. For information on the SPICE toolkit                 
   and/or how to obtain it, please consult SPICE_INST.CAT and                 
   SOFT.CAT.                                                                  
                                                                              
   Refer to the FRAMES.REQ document provided with the SPICE toolkit to get    
   more information about definition and usage of the frames within SPICE     
   system.                                                                    
                                                                              
Venus Express FK Files                                                        
======================                                                        
                                                                              
   This file describes the contents of the DATA/FK directory of the Venus     
   Express SPICE dataset.                                                     
                                                                              
   The files describing the frames of the spacecraft and its instruments are  
   produced manually with the information supplied by the VENUS EXPRESS teams.
   Other FK files (for tracking stations) are provided specifically for the   
   Radio Science investigation.                                               
                                                                              
   All FK files (*.TF) contained in this directory are UNIX text files. In    
   order to be used in a non-UNIX environment, they have to be converted to   
   the appropriate end-line convention. For example, the lines have to be     
   terminated by a <CR><LF> combination for Windows platforms.                
                                                                              
                                                                              
Venus Express FRAMES Kernels Contained in this Data Set                       
=======================================================                       
                                                                              
   Note that when more than one version of a kernel is available in this      
   dataset, the most recent supersedes all the others, and therefore it should
   be used.                                                                   
                                                                              
   The following Venus Express FRAMES kernels are provided in this dataset    
   (only name portion of the file name is shown; extension of all file names  
   is '.TF'):                                                                 
                                                                              
     EARTH_TOPO_yymmdd     FK kernel for the topocentric reference frames for 
                           the Deep Space Network (DSN) stations. This kernel 
                           was released on yy-mm-dd.                          
                                                                              
     EARTHFIXEDIAU         This kernel makes the IAU_EARTH frame coincide with
                           the earth fixed reference frame.                   
                                                                              
     EARTHFIXEDITRF93      This kernel makes the ITRF93 frame coincide with   
                           the Earth fixed reference frame.                   
                                                                              
     NEW_NORCIA_TOPO       FK kernel for the topocentric reference frame for  
                           the ESA 35m tracking antenna at New Norcia.        
                                                                              
     RSSDvvvv              Generic Frames Definition Kernel for ESA Planetary 
                           Missions. vvvv is the version number               
                                                                              
     VEX_Vvv               Complete set of frame definitions for the Venus    
                           Express Spacecraft (VEX) including definitions for 
                           the VEX fixed and VEX science instrument frames.   
                           This kernel also contains NAIF ID/name mapping for 
                           the VEX instruments. vv is the version number.     
                                                                              
                                                                              
                                                                              
Kernel File Details                                                           
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   The most detailed description of the data in an FK file is provided        
   in meta data 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 this 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, and icy/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).