A rather horrible accounting of what happens if an astronaut floats off into space

The good news: There's a contingency plan for this sort of thing, involving the use an emergency jetpack that can (hopefully) stabilize you and help you maneuver back to the ISS. The bad news: If the jetpack fails, you're pretty much screwed. And you've got 7.5 hours of breathable air to consume while you think about that fact.