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The capacity of producing fresh food meeting crew's nutritional requirements is an essential need for long-term planetary missions. To this end, the European Space Agency (ESA) has commissioned a feasibility study of Food Production Units (FPU) for their application in microgravity, transit and planetary environments. This paper describes the "On Ground Experimental Growth Unit" (OGEGU), which is a ground-based, closed loop FPU concept for plant cultivation, conceived as a first approach in the adaptation of food production systems to Space. The OGEGU design is based on state-of-the-art greenhouse technology. Nine OGEGU key subsystems (external structure, irrigation, lighting, plant support structure, crop handling, crop and seed preservation, climate control, water and nutrient delivery, and waste management) are discussed and implementation options are proposed considering constraints such as power, mass or volume imposed by their eventual use in Space. Potential OGEGU topologies are also outlined. OGEGU subsystems are then dimensioned to accommodate the cultivation of selected crops that deliver up to 40% of the diet requirements for a six member crew. For comparison purposes, two groups with four different crops requiring distinct cultivation conditions in terms of surface and volume are considered. Finally, the resulting OGEGU designs are evaluated and traded-off using the Equivalent System Mass methodology. Copyright © 2005 SAE International

Interest on food production systems based on the cultivation of vegetables for future planetary exploration missions is increasing as these units can help overcoming difficult and costly re-supply logistics. In addition to producing edible biomass by growing vegetable species, these systems can be used in closed loop configuration with bio-regenerative life support subsystems for water and CO2 recycling and O2 production. Aiming at this objective, the European Space Agency (ESA) undertook a feasibility study on Closed Loop Food Systems (CLFS) for Low Earth Orbit (LEO), Transit to Mars and Mars Surface scenarios. This paper describes the study's results. Firstly, candidate crops are selected based on nutritional characteristics and aspects like yield, cultivation surface and volume, and generated inedible biomass. A culture plan for these crops is then established. The design process of a Food Production Unit (FPU) begins with the definition of an On Ground Experimental Growth Unit (OGEGU), a ground reference system that is later adapted to the proposed Space scenarios. For Low Earth Orbit (LEO), two secondary structures options (racks and spiral), fitting a Columbus-sized module, are presented and their food production capabilities are analyzed. Similarly, design options for Transit to Mars and Mars Surface are described. Mass, power and volume budgets are determined and the Equivalent System Mass (ESM) methodology is used for trade-off study. For the LEO options process modeling and preliminary mechanical, thermal, safety and logistics analysis are done. Impacts on the International Space Station (ISS) due to potential FPU implementation are also studied. For the Mars surface scenario, an adapted FPU architecture is presented. Interface issues between FPU and bio-regenerative life support systems are also addressed. The study shows that FPU systems for LEO application could deliver ca. 12% of the food requirements, which makes them a very interesting platform for both space agriculture research and complementing nutritional requirements. For the Mars Surface application provision of up to 40 % food requirements is shown possible. Finally, relevant technological gaps identified throughout the study are outlined. Copyright © 2005 SAE International