Abstract

   CSPICE_SPKUEF unloads an ephemeris file so that it will no longer be
   searched by the readers.

I/O

   Given:

      handle   Integer handle assigned to the file upon loading.

               [1,1] = size(handle); int32 = class(handle)

   the call:

      cspice_spkuef( handle )

   returns:

      None.

Parameters

   None.

Examples

   Any numerical results shown for this example may differ between
   platforms as the results depend on the SPICE kernels used as input
   and the machine specific arithmetic implementation.

   1) Load a planetary ephemeris SPK; then look up a series of
      geometric states of the Earth relative to the solar system
      barycenter, referenced to the J2000 frame.

      Use the SPK kernel below to load the required ephemerides
      for the Earth and the Earth Barycenter relative to the solar
      system barycenter.

         de405.bsp


      Example code begins here.


      function spkuef_ex1()

         %
         % Local constants.
         %
         MAXITR   = 5;
         ET0      = -315576000.0;
         STEP     = 3600.0;

         ABCORR   = 'NONE';
         FRAME    = 'J2000';
         OBSERVER = 'SOLAR SYSTEM BARYCENTER';
         SPK      = 'de405.bsp';
         TARGET   = 'EARTH';

         %
         % Load the SPK file.
         %
         [handle] = cspice_spklef( SPK );

         %
         % Step through a series of epochs, looking up a state vector
         % at each one.
         %
         for i=0:MAXITR-1

            et =  ET0 + i*STEP;

            [state, lt] = cspice_spkezr( TARGET,  et,     ...
                                         FRAME,   ABCORR, ...
                                         OBSERVER         );

            fprintf( '\n' )
            fprintf( 'et = %20.10f\n', et )
            fprintf( '\n' )
            fprintf( 'J2000 x-position (km):   %20.10f\n', state(1) )
            fprintf( 'J2000 y-position (km):   %20.10f\n', state(2) )
            fprintf( 'J2000 z-position (km):   %20.10f\n', state(3) )
            fprintf( 'J2000 x-velocity (km/s): %20.10f\n', state(4) )
            fprintf( 'J2000 y-velocity (km/s): %20.10f\n', state(5) )
            fprintf( 'J2000 z-velocity (km/s): %20.10f\n', state(6) )
            fprintf( '\n' )

         end

         %
         % Unload the SPK kernel. This isn't necessary in a stand-
         % alone program, but it's good practice in functions
         % because it frees program and system resources.
         %
         cspice_spkuef( handle );


      When this program was executed on a Mac/Intel/Octave5.x/64-bit
      platform, the output was:


      et = -315576000.0000000000

      J2000 x-position (km):   -26772058.9514643848
      J2000 y-position (km):   132760135.1677220613
      J2000 z-position (km):    57557579.2735445350
      J2000 x-velocity (km/s):       -29.7772753957
      J2000 y-velocity (km/s):        -5.0656884328
      J2000 z-velocity (km/s):        -2.1979102802


      et = -315572400.0000000000

      J2000 x-position (km):   -26879249.7439419106
      J2000 y-position (km):   132741862.7243705541
      J2000 z-position (km):    57549651.2066062242
      J2000 x-velocity (km/s):       -29.7731620671
      J2000 y-velocity (km/s):        -5.0856683968
      J2000 z-velocity (km/s):        -2.2065710777


      et = -315568800.0000000000

      J2000 x-position (km):   -26986425.6981768459
      J2000 y-position (km):   132723518.3595090210
      J2000 z-position (km):    57541691.9637668282
      J2000 x-velocity (km/s):       -29.7690319295
      J2000 y-velocity (km/s):        -5.1056448242
      J2000 z-velocity (km/s):        -2.2152302239


      et = -315565200.0000000000

      J2000 x-position (km):   -27093586.7536762133
      J2000 y-position (km):   132705102.0859030634
      J2000 z-position (km):    57533701.5509854183
      J2000 x-velocity (km/s):       -29.7648849936
      J2000 y-velocity (km/s):        -5.1256176961
      J2000 z-velocity (km/s):        -2.2238877108


      et = -315561600.0000000000

      J2000 x-position (km):   -27200732.8499865979
      J2000 y-position (km):   132686613.9163857996
      J2000 z-position (km):    57525679.9742503539
      J2000 x-velocity (km/s):       -29.7607212708
      J2000 y-velocity (km/s):        -5.1455869940
      J2000 z-velocity (km/s):        -2.2325435301

Particulars

   A file is removed from consideration by the readers by a call to
   cspice_spkuef.

   The file table entry corresponding to the file referenced by
   handle, is removed. Also any segment table entry which came from
   the specified file is also deleted.

   If the file specified by handle does not appear in the file table,
   nothing happens.

Exceptions

   1)  Unloading a file that has not been loaded is a no-op.
       No error is signaled.

   2)  If the input argument `handle' is undefined, an error is
       signaled by the Matlab error handling system.

   3)  If the input argument `handle' is not of the expected type, or
       it does not have the expected dimensions and size, an error is
       signaled by the Mice interface.

Files

   The file referred to by `handle' is unloaded.

Restrictions

   None.

Required_Reading

   MICE.REQ
   SPK.REQ

Literature_References

   None.

Author_and_Institution

   J. Diaz del Rio     (ODC Space)

Version

   -Mice Version 1.0.0, 09-AUG-2021 (JDR)

Index_Entries

   unload SPK ephemeris file