Could he punch someone into space?

My answer is no, without even reading the link. I think that he could throw someone there (though they’d get cooked from the air friction on the way up), and they’d come back down unless they had escape velocity when they got to the top of the atmosphere, because there wouldn’t be an orbital insertion impulse. But if he punched them hard enough to do so, his fist would probably just take their head off. If he did it through their solar plexus, it would probably just go right through. People don’t consider the structural issues associated with superheroes and normal-human interactions with them.

Now Ralph Kramden, on the other hand… But then, he never carried out the threat.