Given the challenges of regular resupply missions to distant destinations, such as the Moon or Mars, it's imperative to prioritize resource recycling and in situ food production. In this view, greenhouse modules, which enable food production, atmosphere regeneration, and water recycling, will be the central piece of bioregenerative life-support systems for long-duration crewed missions. To be sustainable, they will need to use few resources, present low risk, be robust, reliable, and resilient.
Current plant growth systems for space missions, whether small research facilities or oversized engineering concepts, fail to adequately meet the challenges of sustaining astronauts with food in space. Existing space greenhouse modules have typically been designed based on spacecraft volume limitations or as ambitious engineering designs for planetary missions.
The objective of the SERENITY (Space & Earth Reliable greENhouse desIgn meThodologY) project is to develop a methodology starting from the mission scenario (i.e., location, duration, crew size, nutritional targets, available utilities) and enabling users to generate different design solutions, with requirements on the system’s mass, energy, crew time, efficiency, reliability, sustainability, and risk for humans. These solutions are generated using the multi-objective optimization platform for energy systems, OSMOSE (OptimiSation Multi-Objectifs de Systèmes Énergétiques) developed at the laboratory of Industrial Processes and Energy Systems Engineering (IPESE) at the Ecole Polytechnique Fédérale de Lausanne (EPFL). The approach is incremental, starting from simplified systems and limited requirements to more complex systems. The end goal is to provide a framework for users and developers, where they can interact with each other, add subsystems that are tailored to their needs, and choose their own level of complexity, while contributing to the improvement of this methodology. The entirety of the codes is deposited in a GitHub repository (https://github.com/LuciePoulet/SERENITY) to be widely available and to allow a modular use of the methodology.
In this talk, the overall framework is presented with its potential and its limitations. The main subsystems, corresponding to the main greenhouse module functions, with their different options for unit operations, are detailed. The different scenarios, with their associated constraints are reviewed and, as an illustration of this methodology, a case study on a simplified greenhouse module is detailed, for one of the four scenarios, with the goal of minimizing the system mass.
This project has received funding from the European Union’s Horizon Europe research and innovation programme under the Marie Sklodowska-Curie grant agreement N° 101067017.

The success of future space exploration will rely on the development of Bioregenerative Life Support Systems (BLSSs) to regenerate resources to sustain human life. BLSSs consist of artificial ecosystems where carefully selected organisms, including bacteria, algae, and higher plants, are arranged in a series of recycling steps to convert crew waste into oxygen, potable water, and fresh food. Among these, plants show the greatest potential as bio-regenerators, since they can regenerate air, purify water, and provide nutrient-rich food. Light plays a crucial role in plant growth in controlled environments as it provides energy for photosynthesis and regulates various functions like transpiration and photomorphogenesis. Light intensity, photoperiod, and spectral composition significantly impact crop productivity and nutritional and nutraceutical value of plant-based foods. Therefore, one of the main challenges in growing plants within BLSSs is providing artificial lighting with sufficient intensity and the right spectrum.
The objective of the experiment was to assess the effects of supplementary lighting using monochromatic light-emitting diodes (LEDs) with red:blue (R:B) at the ratio of 2:1 compared to natural light (control), on potato (Solanum tuberosum L. cv. ‘Colomba’) as candidate staple crop.
The experiment was carried out in an unheated greenhouse, using a prototype system simulating vertical farming, which can be easily adapted to a BLSS. The plot with supplementary LED treatment was shaded with a polystyrene panel, and the light intensity deficit was integrated with R:B light up to a maximum of 400 µmol s-1m-2 Photosynthetic Photon Flux Density (PPFD). The emitted light intensity was dynamically regulated in the shaded plot via two PPFD sensors placed at canopy level, based on the difference between the shaded area and the unshaded control.
Various morphological and growth parameters, as well as the nutritional and nutraceutical value of the edible products, were measured.
Results revealed that supplementary R:B light significantly enhanced leaf photosynthesis and improved plant growth compared to sunlight. Specifically, net photosynthesis increased about 1.5 times compared to the control. Accordingly, leaf biomass and leaf area increased twice and 1.6 times, respectively, and tuber yield was 28.6% higher compared to natural light.
These findings demonstrate that manipulation of light spectrum is an efficient tool to improve plant performance in potato and provide valuable insights for designing optimal lighting strategies in crop modules in BLSSs, maximizing both the food production and the plant regeneration potential.

Keywords: LEDs, Solanum tuberosum L., controlled environment, Bioregenerative Life Support Systems (BLSSs)