OPTIMIZATION OF THE PLANT ILLUMINATION SYSTEM STABILIZING OXYGEN CONCENTRATION IN THE GAS MEDIUM WITHIN A PROTOTYPED BIOTECHNICAL CREW LIFE SUPPORT SYSTEM

Abstract

We validated an approach to optimization of the higher plant illumination system within a biotechnical life support system (BTLSS) in order to reduce power consumption and equivalent harvest mass. The challenge was to stabilize oxygen concentration in the air of a pressurized compartment. To compare different approaches to power consumption optimization, we used publications on a study in which BTLSS with a 27 m2 cultivation area provided leaf vegetables (Chinese cabbage) to 2 human subjects. Time course of the daily energy and O2 consumption was divided into 5 periods according to specified levels of loading. In context of a Moon mission scenario, the optimal photon flux density and white-red light ratios were calculated using regression models for each day between vegetation days 8 and 14. Experimentally obtained models of photosynthetic productivity were used to calculate a daily lighting level required to produce oxygen in the amount sufficient for the crew. It was shown that this method of O2 stabilization makes possible, within 7 days, power consumption reduction by 68 % and increase of the coefficient of light energy consumption by harvest in 2.3 times as compared to the control growing under continuous invariable illumination. Moreover, equivalent mass of the illumination system reduced 30 % as compared to the control.