I was thinking about this a few minutes ago. Imagine being an astronaut in space working on say the space station, when your connecting cable breaks and due to inertia you go flying through space. How would the mind possibly be able to take it. You are flying through emptiness, certain to die, no way to kill yourself other than remove your helmet. You're going to live for some time, either untill you run out of oxygen (assuming the oxygen wasn't being supplied by the ss), or die due to lack of water, lets say a few days. Just floating through nothingness, contemplating everything, waiting to perish, in the middle of nowhere.
Honestly if you were on the space station and broke off, you would free fall back down to earth at 20,000 MPH Given the fact that you are in a space suit, you would survive re-entry as you would be low drag, however you would be moving at supersonic speeds through the atmosphere and would quickly crater against the earth Now if we are talking hypothetically that you were actually in DEEP space and outside of the major influence of a gravitational body, and you knew you would be free floating for a long period of time, then I would just take my helmet off as soon as I realized it. If you are interested in the first example I gave, there actually was a guy that sky dived from 30KM at the boundaries of space. http://en.wikipedia.org/wiki/Project_Manhigh