However , a possibility remains that during the NUMBER@1 close encounter with LOCATION@1 , ORGANIZATION@1 would pass through a gravitational keyhole , a precise region in space no more than about NUMBER@2 meters across , that would set up a future impact on April NUMBER@3 , NUMBER@4 .

During NUMBER@1 , ORGANIZATION@1 would go through a `` gravitational keyhole '' , an area in space no more than about NUMBER@5 meters across .
