Ecosystems to be established during space exploration for life support will likely be subject to stress due to restricted or unsteady water, oxygen, light, photoperiod, temperature and other environmental factors. Our understanding of the response of those systems to these and other unique stresses can be enhanced by model analysis and simulation. An example of a simple aquatic system consisting of two species of primary producers and one cladocera species subject to combinations of multiple stressors is presented. A model is built taking into account lethal and non-lethal effects, such as changes from asexual to sexual reproduction, and their ultimate impact on population and system stability. Sensitivity and scenario-consequence analysis are then used to study stressor combinations.