Why not whip Doomsday Into Space??

i never really even though about this until superman did his comet suplex to doomsday, but why didnt he just throw him into space instead? Or into the sun?! those are pretty sure-fire ways to eliminate a threat forever. Doomsday cant fly so...

i mean, superman ALREADY brought him into space... i thought he was gonna throw him into spae and go after him again after since theres so much left in the movie at this point. Still, makes no sense that he did not try it