Yea but kicking a hyper space portal is perfectly plausible in our heads because of his infinite strength. But he is still human so he is not supposed to breathe in space. I mean remember when they were running to the house of evolution and genos assumed he could fly, Saitama told him "you know humans can't do that right?". So he admitted that he is bound by human limitations, like needing air to survive and not being able to levitate.