Life sciences research facilities planned for the U.S. Space Station will accommodate life sciences investigations addressing the influence of microgravity on living organisms. Current projects within the Life Sciences Space Station Program (LSSSP), the Life Sciences Space Biology (LSSB) and Extended Duration Crew Operations (EDCO) projects, will explore the physiological, clinical, and sociological implications of long duration space flight on humans and the influence of microgravity on other biological organisms/systems. Initially, the primary research will emphasize certifying man for routine 180-day stays on the Space Station. Operational crew rotations of 180 days or more will help reduce Space Station operational costs and minimize the number of Space Transportation System (STS) shuttle flights required to support Space Station. A 180-day crew rotation schedule will be operationally acceptable if there is reasonable assurance that crew health, performance and productivity will be maintained, and that postflight crew recovery from adverse microgravitational effects will occur within a reasonable period of time. As the medical assessment required to proceed with a 180-day crew rotation schedule matures, the opportunities will expand for fundamental and long-range research within the LSSB Project. Fundamental biological research within the LSSB will include space physiology, gravitational biology, exobiology, Controlled Ecological Life Support System (CELSS), and may use animal models to quantify or characterize selected human physiological responses to microgravity. Long-range research will focus on developing an efficient technology for maintaining and recycling food, water and atmospheric resources required to sustain human life during long-duration missions, such as interplanetary visits.This paper addresses the current life sciences planning effort within the JSC Life Sciences Project Division (LSPD) for the LSSB Project.