This article explores the application of theoretical knowledge to clinical situations based on general systems theory and space health requirements to familiarize health care providers with requirements for the space environment. Preparation for extended periods of humans living in the space environment requires carefully planned delivery system that will promote and maintain health. Past, present, and future efforts for the establishment of'space health delivery systems are discussed. The National Aeronautics and Space Administration (NASA), Man-systems integration standards, NASA-STD-3000 Volume 1-MSIS, Revision B (1995, July), Houston, TX, National Aeronautics and Space Administration documents will be reviewed. Health care services will be supported by the available crew health care and emergency services systems. Providing health care in the extreme space environment with limited resources in which to carry out health practices offers challenges to health care providers.