In week one, the 12 candidates are thrown in at the deep end. They are first challenged to hover a helicopter, with no previous experience, to test how quickly they can learn a new skill. Astronaut Chris Hadfield sets them this test as it's one astronauts need to master and it shows the candidates just how high the bar is being set.Dr Kevin Fong then puts the candidates through a Beep Test that pushes them to their physical limits. Next, Chris runs a test for mental acuity used by space agencies to weed out candidates during their own selection processes.Psychologist Dr Iya Whitely then interviews the candidates to look for facial micro-expressions that could reveal who would be best-suited to long-term missions in space.Next, with no hospital in space every astronaut is trained in basic medicine and the candidates must face their fears by taking their own blood and, finally, they're confined to small personal spheres as a test for claustrophobia. Not everyone meets the high standard Chris has set, but which candidates will have what it takes to get through to the next stage of the selection process?