A Bioregenerative Life Support System consists of two levels of systems: the total life support system and the crop production system which is an integral part of it. A set of performance requirements for a crop-based BLSS and models for the BLSS and the crop production system are proposed. Four crop growth processes are defined - assimilation, transpiration, allocation, and uptake - which relate directly to the processes required for life support. Models are described which identify the appropriate environmental control parameters for each of these processes. Analysis demonstrates that crop canopy temperature control is essential to management of crop processes in a BLSS.