Aside from the minor orbital mechanics impossibilities and the Spielbergian dead kid tear-jerking, why did she keep taking off her helmet? If you were entering a spacecraft you had never been inside in the middle of a debris storm that had caused every one else to abandon ship, would you take your helmet off? I think I’d leave it on.
Of course the reason she took it off was because you don’t give Sandra Bullock 10 points of the gross and then hide her in a bulky spacesuit and helmet for 95 minutes. Same reason the pilots in BSG had helmet lights shining in their eyes – you couldn’t see their faces otherwise.
I’d also hunt around a couple of minutes for more oxygen before I cast off on an unplanned space walk, even if the ship were destroyed. Gotta be an oxygen bottle around here someplace.
I don’t care if you break the laws of physics, but logical people (doctors, astronauts, scientists) should be logical within your own movie. This is the same problem Prometheus had. Not science – character.
Anyway, it was an effective use of 3D (and one which didn’t give me a headache), except when it pulled me out to wonder why the dead kid  and why are supposedly smart people being stupid.
 Same as I cringe when I see a dog in a movie anymore – I know the dog is going to get it. Cats never get it, they just cause minor characters to get got.