es</a></h4>
<PRE>
 
   This routine computes positions using SPK files that have been 
   loaded into the SPICE system, normally via the kernel loading 
   interface routine <a href="furnsh_c.html">furnsh_c</a>. See the routine <a href="furnsh_c.html">furnsh_c</a> and the SPK 
   and KERNEL Required Reading for further information on loading 
   (and unloading) kernels. 
 
   If the output position `ptarg' is to be expressed relative to a 
   non-inertial frame, or if any of the ephemeris data used to 
   c