For reasons of safety as well as cost, increasingly lengthy space missions at unprecedented distances from Earth in the 21st century will require reductions in consumables and increases in the autonomy of spacecraft life support systems. Advanced life support technologies can increase mission productivity and enhance science yield by achieving reductions in the mass, volume, and power required to support human needs for long periods of time in sterile and hostile environments. Current investment in developing advanced life support systems for orbital research facilities will increase the productivity of these relatively near-term missions, while contributing to the technology base necessary for future human exploration missions.With its recent reorganization, NASA has concentrated all activities concerned with the human element of space exploration into a single office, the Office of Life and Microgravity Sciences and Applications, under the direction of the Life and Biomedical Sciences and Applications Division. This consolidation of research and development activities marks the initiation of a synergistic life support program with a broad range of supporting elements including human factors, science requirements, mission-specific requirements, aspects of medicine and health care, enabling technologies, applications engineering, and systems integration. Thus, NASA is taking a new and more comprehensive approach to life support with the integration of all of these elements into an evolutionary program, with contributions from NASA field centers and unique facilities.