
               both 'MOON' and '301' are legitimate strings that indicate
               the Moon is the target body.

               [1,c2] = size(target); char = class(target)

                  or

               [1,1] = size(target); cell = class(target)

      et       the ephemeris time(s), expressed as seconds past J2000
               TDB, at which to compute the surface intercept point on
               the target body (this epoch represents either the time of
               signal reception, or t