In a role-playing study designed to test the hypothesis that mission destination and mission duration affect the perceived habitability of spaceflight environments, college students read one of four space mission scenarios which varied destination (the moon or Mars) and duration (one month or one year). They then completed a 7-factor environmental rating scale. Whereas mission destination had no effect on perceived habitability, the environment was less acceptable for the extended than for the brief mission, and women rated the environment less favorably than did men. Results suggest that spaceflight environments are multidimensional, and that to assess habitability we must not only ask, "What is the environment?" and "Who are the environment's occupants?" but also, "What are the conditions and circumstances surrounding the environment's use?"