Future long-duration manned space missions, such as planetary exploration and settlement, will require more advanced life support technologies than those used for the Orbiter or the initial configuration of Space Station Freedom. In Dr. Ride's report entitled “Leadership and America's Future in Space” (1)*, human exploration of Mars is the most daring of the four initiatives proposed. This initiative includes unmanned sample return missions, one-year manned sprint missions, and eventual habitation of Mars. Currently, NASA's Office of Exploration is conducting a number of case studies which also examine the possibility of sending humans to the Mars system, whether it be to the moon Phobos or a visit to the planet itself (2). The advanced life support systems presently under development for such missions include bioregenerative components, along with more traditional physicochemical components (3).This paper explores the application of bioregenerative subsystems to an environmental control and life support system (ECLSS) for long-duration manned Mars missions and discusses the integration of new bioregenerative subsystems into a computer model of an ECLSS for this type of mission. The Mars sprint missions outlined in NASA's case studies will last approximately 14 months with a 20-day stay on the planet surface or on the surface of Phobos. These mission scenarios provide the basis for the ECLSS computer simulation. The bioregenerative subsystems will provide partial closure of the food loop with food production and partial waste recovery of the plant material. The model is being developed using both previously existing physicochemical computer simulations and new bioregenerative component simulations. A plant growth unit which simulates the growth cycle for white potatoes includes algorithms of CO2 and H2O consumption, and O2 and food production. The manned Mars sprint mission ECLSS model will be discussed with regard to system configuration and plant model structure.