Maintaining the psychological and behavioral health of humans during long-duration space missions is of great importance for the future success of space exploration, (including a Martian expedition). The hostile space environment includes microgravity, radiation, confinement, isolation, monotony, sensory deprivation, and boredom (Gazenko et. al., 1976). The extreme nature of the space environment has been found to adversely impact the psychological, social, and physiological well-being of humans in space (Manzey & Lorenz, 1999; Davis, 1999). One proposed countermeasure for the negative impacts of long-duration space missions is growing and tending plant life (Bates et. al., in press). Interactions with plant life on earth-including gardening and viewing scenic vistas-have been found to promote health recovery (Ulrich, 1984), stress recovery (Ulrich et al, 1991), well-being (Ulrich & Parsons, 1992), interpersonal communication (Rice, et. al., 1980), and community cohesion (Waliczek et al., 1996). The potential efficacy of plants as a countermeasure to the negative impacts of long-duration space missions has not yet been investigated in space or in the simulated space environment. During the Mars 500-day Chamber Study and other preparatory chamber studies, the potential benefits of plant life in space will be empirically tested. Data will be collected from participants in chamber studies using a computer-based, self-report questionnaire and monitoring system that will record the frequency and duration of interactions between participants and plant life. The questionnaire will include items concerning the participants’ past nature-related experiences, mood, psychological, and social impacts that relate to their interactions with plant life. Contextual differences and plant preferences will also be determined. It is expected that those who interact (e.g. passively or actively) with plant life will realize some of the predicted benefits of plant life in the space environment. Results from this study can be used to improve the quality of life in space and assist in maintaining psychological and behavioral health for humans during a Martian expedition.