PLANT-GROWTH LIGHTING FOR SPACE LIFE SUPPORT: A REVIEW
The lighting system is one of the most important components of a greenhouse or chamber that will be used for plant growth in an Advanced Life-support System (ALSS). Several designs of such lighting systems have been proposed including the use of natural sunlight with supplemental electric lighting. Although electric lighting is energy intensive, it is necessary when balanced against the hazards and limitations of plant growth under natural sunlight on the surface of the moon or Mars. The characteristics of different electric light types are reviewed, and functionality for space application is compared. Different lighting systems used in Earth-based advanced life-support (ALS) simulations are highlighted. A new design using light emitting diodes (LEDs) for intracanopy lighting, i.e. lighting entire crop canopies for energy savings and crop enhancement, is discussed. When the benefits of LEDs are combined with the advantages of intracanopy lighting, electric lighting for ALS becomes increasingly feasible.