Task: Text Simplification
Input (English): david w. dunham , the minor planet bulletin , volume 6 , p.13-14 -lrb- december 1978 -rrb- ads archive copy however , careful examination in 1993 , using the hubble space telescope , failed to locate a secondary.
Output (English): careful examination in 1993 , using the hubble space telescope , failed to locate a secondary.