Investigation of optimal Light Environments for Crops in EDEN LUNA

Kurzfassung

To return to and to build a long-term base on the Moon and other celestial bodies, a multitude of difficulties regarding life support need to be addressed, one of which is the provision of food. With the EDEN LUNA project, the DLR develops Controlled Environment Agriculture technologies to be used in planetary space stations to provide Astronauts with fresh produce. To maximise the growth of crops in the EDEN LUNA future exploration greenhouse (FEG) and to minimise the energy input, the development of individualized light environments for two crops (lettuce and cucumber) was attempted in this thesis. These light environments were determined by literary research for general use and adapted for the use in the EDEN LUNA FEG. The light environment for lettuce was evaluated and adapted experimentally. Power consumption of the light environments were estimated by taking snap-reading and extrapolating over the whole growth period. It could be shown that lettuce requires a light intensity of about 220 to 230 µmol m2s. A higher blue light ratio led to a denser growth of the lettuce, while red and far red light made the lettuce spread out more. Green light might allow the lettuce to grow denser as it increases the photosynthesis in the lower layered leaves of the plant. A sensory analysis showed that the new light environment produced sweeter lettuce with higher crispness if the light intensity was between about 220 to 230 µmol m2s. The developed light recipe did not lead to a higher yield than the control. It was estimated that the experiment consumed slightly more ( ~3%) energy than the control.