As we dream of sending humans to Mars, the psychological problems of a mission loom large. As part of Radio 4's Mars season. Claudia Hammond investigates the mind-set behind the desire of those of us who want to colonise the red planet. What does it take to survive the confines of a 9 month journey and the enclosed pod-like environments that mission leaders envisage will be the housing needed to occupy this inhospitable planet? Claudia meets the wannabe Martian explorers who've been sampling similar long term simulations here on earth and the psychologists who've overseen the design,selection and planning for future communities in space. Producer Adrian Washbourne.