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.

Originally released by BBC Worldwide Learning, 2017. Streaming video file encoded with permission for digital streaming by Infobase on November 21, 2019.