That's the current incarnation of Supes (the post-Crisis one), although I think it's outdated now; he developed the power to internally process oxygen, using a method taught to him by --IIRC-- Mongul, the son of one of his enemies. Thus he can stay in space nearly indefinitely.

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"If this were play'd upon a stage now, I could condemn it as an improbable fiction."
Shakespeare, Twelfth Night
Illuminati's Razor-The most complicatedly evil answer is usually the most correct answer. - Fazor
"Every book is a children's book if the kid can read." - Mitch Hedberg
"Distance doesn’t matter much in space, where if you just start a thing off with the right kind of shove, sooner or later it will get where you want it to go." -Frederik Pohl, Mining the Oort