This week, the competition becomes more intense as the remaining astronaut candidates head off to a secret facility in Sweden. They are deliberately deprived of oxygen to see if they can recognise the signs of hypoxia, critical for an astronaut on a spacewalk. Their ability to withstand the strong g-forces of space travel is tested in a human centrifuge. Their communication skills are put to the test as well as their ability to impress Chris and the panel with their specialist space knowledge. Show less