e surface
                  must be less than a small margin. See the Parameters
                  section below for a description of this margin.

   the call:

      normls = <b>cspice_srfnrm</b>( method, target, et, fixref, srfpts )

   returns:

      normls      is an array of unit length, outward normal vectors
                  corresponding to the points in `srfpts'.

                  [3,n] = size(normls); double = class(normls)

                  Elements

                     normls(1,i)
        