Living in space must entail life in a cramped confined space, as well as monotonous sounds, smells, food and scenery. There are still few studies on human health in long-term closed habitation. We have investigated changes in the psycho-physiological status of humans in a series of closed habitations with re-circulated air, water and waste products. In this report, we describe a closed habitation experiment conducted at the Institute for Environmental Sciences and the outcomes obtained through discussion in our working group.