The carbon cycle in a bioregenerative life support system with a soil-like substrate

A mass-flow model of carbon cycle in a bioregenerative life support system (BLSS) including Resource, Plant Growth, Food Processing, Human, Waste Processing, and Waste Storage Modules was developed. A human received food from Plant Growth and Resource Modules. Plants were assumed to be growing on the soil-like substrate (SLS). Another function of SLS was balancing the carbon cycle. The input of BLSS was set to 81 g of carbon per day along with food from the Resource Module. To balance the carbon cycle an equal amount of carbon was removed from BLSS along with urine, feces, plant wastes, and SLS. A mass flow of carbon cycle was used to simulate the effect of light intensity on the basic parameters of the Plant Growth Module. It was calculated that the stationary dry mass of SLS increases from 10 to 35 kg m^{- 2} with increase canopy-level daily photosynthetic photon flux (PPF) from 34 to 178 mol m^{- 2} d^{- 1}. On the contrary dry mass of SLS needed to provide one person with plant food is not dependent on light intensity.