I found this excellent timeline elswhere in regards to breathing in space
It all began with Superman #82, where the Eradicator - in order to save Kal-El from the fatal kryptonite ray fired by the Cyborg - absorbed it, channeling the energy in a different way. This resulted in Clark regaining his powers (that energy has been called by Professor Hamilton "Kryptonite X"), and eventually, it gave his abilities a power boost.
Then, Superman noted that his super-powers began to increase, most precisely in Man Of Steel #30 (Feb. 94), where he knocked out Lobo with only one blow. In this issue, he also, discovered that he was faster than a space ship and did not need an oxygen mask in order to stay in space for a long period of time.
All these changes led to a saga in which Superman had grown "too-powerful" and become a danger to earth's people. Ultimately, the Parasite (in Action Comics #699) absorbed Superman's excess energy, allowing him to be normal again. At this point it is not clear if the Parasite reduced Superman's powers to their normal levels (as established by John Byrne) or if Parasite only depowered him to the level he was at just before his abilities went out of control (Man of Steel #30).-
In the letter-column of Superman #0 (October 94), DC said that Superman "was simply depowered to the level he was at just before his abilities went out of control, so he is able to travel in space...and that is a good power level for us and for you, superfans, too".-
So, at this point, there is no problem. Superman is more powerful and the Parasite absorbed only the excess energy that was making him a danger. He remained at the power-level introduced in Man Of Steel #30: He could fly at the speed of light -or faster, was stronger and more invulnerable, and he could stay in space for days or weeks without needing oxygen.
In the limited series "Hunter & Prey" in 1994, where Superman battled Doomsday for a second time, he said to Maxima (issue 1) that he could travel in space easily. In issue 2 - in a fight against the Cyborg - he states that he was stronger, and knocked out the villain with a blast of heat-vision, the beams of which were depicted bigger than before.
In the saga of "The Trial" (mid 1995), Mope and Leeya (two aliens) purchased a special vehicle to travel in space, and Superman said he did not need one, and flew the interplanetary distances under his own power. But, however, he needed to use an oxygen mask.
Here it is not clearly stated if he used the mask in order to survive or if he only used it to maintain communication with his partners in the vacuum of space. I think, however, that he only used it, so that he could speak to Mope & others. In Superman #108,(part of the same storyline), Superman -in order to save Mope, who was put in a rocket traveling at hyperspace to Krypton by the tribunal- follows the rocket at a same speed (see page 19), but could not save him.
Once again, we notice that he is more powerful than before, at the level DC referred to in the previously mentioned letter-column. Then, in Superman #112, Kal flies all the way to Mars with no need of oxygen mask.
continuity error time The real mess began in Man of Steel #66 (April 97) where Superman says: "I don't have time to rush home for my breathing mask...I can hold my breathe for an hour, maybe more if I have to." What's going on here? A few issues before he says that he can travel in space with no need of oxygen, follows a rocket that travels through "hyperspace" with no problem, but now he needs an oxygen mask? It is not clear.
or
During that year, a reader postulated that this was because Superman lost his powers during the "Final Night" saga. When he regained them in Man Of Steel #64, it was at their basic levels, because the Eradicator's extra energy (Superman 82) dissipated when Superman lost his abilities.-
Are you still with me? I know it may be difficult, but all I want to say is, why mess around when a clear power limit was established by previous editors and writers? If you change Superman's powers in order to make him more or less powerful, at least do it in a clear way.
And finally, I noticed that ever since Superman regained his original powers in March 1998 (remember the energy-based Superman? Awful, really), he is - without a doubt - much more powerful than before.
But, this time, the team of writers explained very well why Superman does not need to breathe in space. Namely, Mongul Jr. trained him how to overcome the lack of oxygen and said that Superman's own conscience imposes limits on his super-abilities.
In conclusion, Superman is now, without a doubt, more powerful. He's not exactly as powerful as he was Pre-Crisis, but he's very close. For example:
1) In Superman #167, he moves Krypton (with help of several of Jor-El's machines, however).
2) In Superman #171, he travels in deep space without an oxygen mask.
3) In Action Comics #782, he moves Warworld all by himself.
4) In the "Infestation Saga" we finally see him with an oxygen mask in space, but he used it only after spending a week in space (not two hours like before) (see Man of Steel 113, page 8, panel 4).
I think it clears everything up to everyone satisfaction, yes he needs to breathe, maybe 52 breaths a year.
It also answers it he can move planets at present.
- Whirly
