General Information About SPICE FRAMES Kernels
==============================================

   In the SPICE system, the FRAMES kernel contains 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. Frequently FKs
   also contain mission-specific NAIF body name to ID mappings.

   The frame definitions information contained in the file can be
   utilized 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 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 data set.
                                                                              
   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
   with lines terminated by <LF> only.
                                                                              
                                                                              
Venus Express FRAMES Kernels Contained in this Data Set                       
=======================================================                       
                                                                              
   Note that when more than one version of a kernel is available in this      
   data set, the most recent supersedes all the others, and therefore it
   should be used.
                                                                              
   The following Venus Express FRAME kernels are provided in this data set:
                                                                              
     EARTH_TOPO_yymmdd.TF  FK kernel for the topocentric reference frames for
                           the Deep Space Network (DSN) stations. This kernel 
                           was released on yy-mm-dd.                          
                                                                              
     EARTHFIXEDIAU.TF      This kernel makes the IAU_EARTH frame coincide with
                           the EARTH_FIXED reference frame.
                                                                              
     EARTHFIXEDITRF93.TF   This kernel makes the ITRF93 frame coincide with
                           the EARTH_FIXED reference frame.
                                                                              
     ESTRACK_Vxx.TF        ESA Ground Stations topocentric frames.
                                                                              
     RSSDvvvv.TF           Generic Frames Definition Kernel for ESA Planetary
                           Missions. vvvv is the version number               
                                                                              
     VEX_Vvv.TF            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.

     VEX_DSK_SURFACES_Vvv.TF

                           FK containing Surface definitions for the
                           Venus Express structures DSKs surfaces.

                                                                              
Kernel File Details
===================

   The most detailed description of the data in an FK 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), Matlab (Mice), and Java
   (JNISpice) and the user can choose any one that suits him/her.

   The SPICE routine FURNSH can be used to load a kernel file into a
   SPICE-based application to make kernel data usable with SPICE
   APIs.

   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).