Observing that the explosion of the space shuttle "Challenger" had a profound impact upon the American public, this paper argues that its most direct impact was upon the National Aeronautics and Space Administration (NASA). Specifically, the paper argues that the explosion was a crisis that resulted in loss of legitimacy for the space agency. Definitions of two terms are provided. (1) A crisis is defined as a major event in an organization's history that results in change. (2) Legitimacy is defined as a status conferred upon an organization by external social actors that results in a larger social justification of the organization and its activities. The paper then examines the Challenger explosion as a crisis in legitimacy and explores NASA's behavior under crisis conditions. The paper next discusses crisis as loss of legitimacy and reviews NASA's efforts to establish legitimacy both before and after the tragedy. The paper concludes that specific target goals, such as a mission to Mars, are necessary if NASA is to repair the serious damage caused by the "Challenger" explosion and to reestablish itself as a legitimate institution. (FL)