This week, the astronaut candidates fight for their place in the final. Their leadership skills are assessed in a survival test and a 30-metre abseil down a sheer cliff face exposes weaknesses in the group. Chris Hadfield and the panel are joined by two guest experts for probing interviews to grill the candidates on whether they have the 'right stuff'. Those who make it through this stage head off to the Kennedy Space Centre in Florida and carry out a spacewalk dive in an underwater marine lab. Show less