It is logistically unfeasible to supply the crew of a long-term space mission with earth-borne food-products only. Thus, in order to provide sufficient food for space missions exceeding one year, it is necessary to implement a plant breeding system on board, which can at least partly cover the crew’s nutritional needs. In the frame of a European Space Agency (ESA) feasibility study on Closed Loop Food Systems (CLFS) for Low Earth Orbit (LEO), Transit to Mars and Mars Surface scenarios, a nutrition selection algorithm was developed to define well equilibrated and diverse menus able to meet dietary requirements. First, an extensive, diversified crop list was compiled from a broad range of literature sources. Secondly, a database was constructed, containing all gathered information for the selected crops. In the scope of this ESA project, follow-up studies on plant growth chamber design and Equivalent System Mass (ESM) analysis were carried out.
Based on supplying a fixed percentage of the crew’s energy requirement, different scenarios were worked out leading to a set of suitable menus using four crops. Crop performance ranking was controlled by assigning weighing factors to key parameters. The menu composition was further fine-tuned to the dietary needs by varying the relative amounts of the selected crops. Using this approach, nutritional value was optimized.
The crop selection procedure was developed based on a fixed energy input, but has the flexibility to calculate menu compositions using alternative selection criteria, such as minimization of waste, optimization of breeding surface, and fulfillment of specific nutritional needs.
Finally, a trade-off is made considering the optimal culture conditions for each crop represented in the engineered menu. This approach guarantees efficient food-production while minimizing the volume of the food producing unit.