My PhD was in space electronics (near enough), so I can probably answer this. In low earth orbit (LEO), where the ISS and the Shuttle live, there isn't much more radiation than you'd get in a high-altitude aircraft, so chances are that if you were in a pressurised cabin you could use more or less any camera you like and it should just work. You might, very occasionally, have to power-cycle it if the embedded processor glitches, and you might also very occasionally have a bright or dark pixel due to a cosmic ray impact on the CCD.
As for working in a vacuum, I very much doubt that a conventional DSLR would work correctly -- if it worked at all, it probably wouldn't work for very long. You'd probably get outgassing from the lubricants used in the mechanical parts, there's a good chance the shutter would stick in place either due to that or other vacuum effects, the temperatures involved would probably go outside the camera's design parameters, and most likely the CCD would overheat. Another phenomenon called differential charging would probably fry the electronics within a few minutes too. Having said that, a diver's camera housing would probably stand a reasonable chance of working -- they can usually stand quite significant positive pressure, so 1 atmosphere pushing outwards is probably going to be OK, assuming that the materials used in all the seals can cope with vacuum.