%A William J. Clancey %J Habitation %T Participant Observation of a Mars Surface Habitat Mission Simulation %X For twelve days in April 2002 we performed a closed simulation in the Mars Desert Research Station in Utah, isolated from other people, while exploring the area and sharing daily chores. Email provided our only means of contact; all mission-related messages were mediated by a remote mission support team. This protocol enabled a systematic and controlled study of crew activities, scheduling, and use of space. The study was primarily a methodological experiment in participant observation and work practice analysis, gathering quantitative data as part of an ethnographic study. The work practice analysis focused on two questions: Where did the time go?why did the crew feel rushed and unable to complete their work? How can we measure productivity, to compare habitat designs, schedules, roles, and tools? Analysis suggests that a simple scheduling change?having lunch and dinner earlier, plus eliminating afternoon meetings?increased the available productive time by 41%. Furthermore, observation of work practices suggested how to eliminate direct use of GPS devices by the crew, illustrating how an ethnographic study can help produce dramatically new operations concepts. %D 2004 %K analog simulation, activity-based analysis, small group behavior, ethnography, habitation %L cogprints3967