VEX DSK SPICE Kernels
  =====================

       This ``aareadme.txt'' file describes the contents of the
       kernels/dsk directory of the VEX SPICE data server.

       It was last modified on March 9th, 2020 by Marc Costa
       Sitja, ESAC/ESA.


  Contact Information
  ========================================================================

   Alfredo Escalante Lopez, ESAC/ESA +34 91 8131 429 alfredo.escalante@esa.int

   Marc Costa Sitja, ESAC/ESA, +34 91 8131 457 marc.costa@esa.int

   Boris Semenov, NAIF/JPL, (818) 354-8136, boris.semenov@jpl.nasa.gov


  References and required readings
  ================================

       1. ``Frames Required Reading'', NAIF Document

       2. ``DS-Kernel Required Reading'', NAIF Document


  Brief Summary
  =============

       This directory contains the SPICE DS-Kernel files for the VEX
       spacecraft, its structures, and science instruments.

       The data provided within this kernel corresponds to the VEX spacecraft
       body (VEX_SPACECRAFT), excluding the following parts:

          - the S/C bus;
          - the +Y and -Y Solar panels, which are provided in separate DSKs;

       The VEX_SPACECRAFT DSK is centered in the VEX_SPACECRAFT ephemeris
       object and its data is provided relative to the VEX_SPACECRAFT reference
       frame.


  Venus Express DSK Directory Structure
  =====================================

    aareadme.txt            This file.

    VEX_SC_STRUC_Vvv.BDS    SPICE Digital Shape Kernel (DSK)
                            file for VEX structures where
                            STRUC identifier for
                            structure/instrument is:

                              BUS:  for the s/c bus;
                              SAPY: for the solar array in
                              the +Y direction;
                              SAMY: for the solar array in
                              the -Y direction.

    If multiple versions of a DS-Kernel file are provided, always use the
    latest version (unless earlier version is needed for some special
    reasons.)


  Particulars
  ===========

     Up until the expansion of SPICE with the DTM capabilities, these checks
     were performed by defining “engineering” field-of-views for these
     instruments, using the location of each of these sensors within the
     spacecraft and the corner points of the spacecraft bus and solar panels.
     This was a complex modeling, which in some cases was not feasible due to
     the type of frames of interest or illumination sources' nature.

     With the new DTM capabilities, and by modeling the VEX spacecraft as an
     irregularly shaped extended ephemerides object, it is possible to exploit
     the full capabilities of the DTM subsystem to find out whether these
     conditions are met or not given a particular attitude profile of the
     spacecraft at a given time.


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

       The most detailed description of the data in a binary DSK file is
       provided in metadata included inside the comment area of the file.
       This information can be viewed using the utility programs COMMNT and
       SPACIT included in the NAIF Toolkit.


  End of aareadme file.