Space tourism is the big thing right now, if you’re a multimillionaire looking to do something no-one else has done. Or alternatively it takes years to train to be an astronaut – if you qualify. Much of science fiction is dedicated to the thought of life outside Earth’s gravity well. Yet how easy would that be? Discover magazine lists 20 things you probably don’t know about Living In Space. It offers some handy tips to surviving in a vacuum (don’t hold your breath!) as well as some interesting facts about existing astronauts, who grow around two inches on average due to less pressure on their spines. It makes you wonder how many people will want to spend their holidays in zero-g.