Question: in the live chat you said that the radiation in space will kill you, i have been x-ray ed and it didn't kill me (luckily), is it because it was a small proportion or it was different? i will vote for you !!!!

Julian Onions answered on 20 Nov 2014:

In an X-Ray, you only get a small dose of x-rays, and only for a fraction of a second usually. You may notice when you have them taken, that staff usually leave the room. This is to make sure they don’t continually get x-ray doses which would add up and be harmful.

In space, you will get hit by all sorts of radiation. X-rays, gamma rays, ultra-violet and cosmic rays. Usually the atmosphere stops most of these, but in space there is no atmosphere to block them.

They won’t kill you quickly, but if you stayed out in space for a long time, without proper protection (space suits have protection built in) then you’ll eventually get hit by enough of these that your body can’t repair the damage.
This is a real problem on a trip to Mars for instance, which would take about 9 months. Particularly if there was a solar flare, which increases the radiation a lot.