Bio-Regenerative Life Support Systems (BRLSS) based on microbial conversion of organic matter followed by photosynthesis are foreseen as important technologies for the production of food, oxygen and pure water during long-term space missions. Previous scientific investigations towards BRLSS have ranged from fundamental plant physiology under fractional gravity conditions to applied edible crop cultivation in Earth analog constructions, including various technical-biological aspects such as illumination alternatives, nutrient delivery strategies and cultivation strategies. Different primary and secondary structures have been explored for the manufacturing of Lunar greenhouses. Earth-manufactured rigid, inflatable or expanding structures have been reviewed to address characteristics such as mass and volume of required materials, functionality and complexity of installation and maintenance. Despite inflatable primary structure concepts, the structure itself normally represents a major part of the total system mass. Consequently, launcher capabilities, costs, functionality and required maintenance become important limiting factors. In the current context, additive manufacturing (AM) from ISRU materials is an attractive solution. However, the feasibility of AM techniques for Lunar greenhouse concepts have to be pushed further. More importantly, innovative solutions for the combination of ISRU AM and closed crop cultivation have to be demonstrated. Crop-friendly ISRU AM of intricate primary structures to accommodate advanced functionality (e.g. integrated water-based radiation shielding), and to ease maintenance need to be validated. Similarly, the possibilies to use ISRU AM for substructures for crop cultivation such as liquid reservoirs and gullies have to be tested in terms of biocompatibility, especially in closed cultivation systems with recirculation of liquid and gas.
