    The components of 'spoint' are given in units of km.

               dist      the distance between the observer and the surface
                         intercept on the target body. 'dist' is given in
                         units of km.

                         [1,1] = size(surf(i).dist)
                         double = class(surf(i).dist)

               trgepc    the &quot;intercept epoch.&quot;  This is the epoch at which
                         the ray defined by 'obsrvr' and 'dvec' intercept