 number) for the
   Mars Global Surveyor spacecraft clock is:
<P>
 
<PRE>
   4294967295.255
</PRE>
   Numbering the fields from left to right, the time units and moduli of
   the fields are:
<P>
 
<PRE>
      Field           Time unit                Modulus
      -----     ----------------------       ----------
        1       approximately 1 sec.         4294967296
        2       1/256 sec.                   256
</PRE>
   Field 1 is known as the ``sclk_secs count.'' Field 2 is known as the
   ``sclk_fine