The greenhouse is a vital module for a long-duration mission to support fresh nutrition for the crew. This paper discusses two concepts of extraterrestrial greenhouses. The first one considers a habitable greenhouse, which has physical features of the habitat module. Human factors are the main focus of such design, aiming to design an interior garden for the crew. Since the priority is to support the crew's psychological health through interactions with plants, interior gardens are considered in both public and private areas, e.g., in the dining area or exercise module. The second approach is an industrial greenhouse to produce maximum nutrition with the lowest cargo mass and resource consumptions. Such a low-pressure greenhouse has the optimum environment for plant growth. The total interior pressure diminishes from the habitable zone of 10.2-14.7 psi (70.2-101.3 kPa) to the plant's living zone of 4.0 psi (27.6 kPa), and carbon dioxide level jumps from 400 ppm to 1500 ppm. Therefore, the crew would have to use EVA suits for operations within the greenhouse. This paper presents a new concept of a greenhouse as a prebreathing chamber because the pressure value does not affect the plant growth cycle. A greenhouse module would accommodate a spectrum of pressure, oxygen, and carbon dioxide levels from the plant's to human's living zones. To prevent decompression sickness, the crew has to dedicate 2-4 hours for prebreathing in an airlock before and after each EVA. From a psychological standpoint, spending time in a greenhouse environment would be a better alternative to airlock conditions. Besides, exercising by the plants, gardening, and/or relaxing after an EVA would be more beneficial for the crew comparing to spending hours in a tight airlock. Moreover, the environmental control and life support system (ECLSS) of the greenhouse remains independent from the habitat and in case of any emergencies can function separately and help the crew to survive. In the long term, a lower level of oxygen reduces oxidizing of the interior of the module. In summary, this paper presents a responsive design concept for the described interior transitions. The proposed design is evaluated using figures of merits (FOM) by the level of their impact on the overall mission planning and success.
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