In week four the candidates leave the German Space Agency behind and head to a secret location in Sweden to face astronaut Chris Hadfield's toughest tests so far. Here, in a military installation, the panel will discover who can cope with a crisis in space.
The candidates will be put through a potentially life threatening test of hypoxia – a deadly condition in which the body is deprived of oxygen.

It's the final. The remaining candidates are on Florida's Space Coast to face the toughest tests of the entire selection process. The question astronaut Chris Hadfield wants the tests to answer is this: would I want this person in the seat next to me waiting for launch?