Design of Microalgae Photobioreactor Experiments on the Moon: Challenges, Possibilities and Research Plan

The Artemis program marks the return of humanity to the lunar surface. This will be the first step towards future lunar settlements. With that in mind, the possible advantages of microalgae cultivation as life support systems for lunar surface are currently being investigated. The next step is now to establish a state of the art in microalgae cultivation procedures based on Photobioreactor (PBRs) and to develop systems ready to be used. Thus, this article describes the challenges of growing microalgae on the lunar surface and presents a research plan for how the Professorship of Human Spaceflight Technology at the Technical University of Munich aims to design microalgae PBR experiments for a future lunar base. Different cultivation conditions will be considered, as well as the possibility of using the resources present there (e.g. regolith, urine, etc.) and how that could affect microalgae growth and biomass composition. New steps in biotechnological research are also considered and described, e.g. tests in a relevant environment, the use of a clinostat to evaluate the effects of partial gravity at the cellular level, how radiation affects biological systems as well as the use of microalgae to treat wastewater or human and food waste or to revitalize the air. Finally, the long-term microalgae culture on the lunar surface opens the door to various research possibilities. The molecular and physiological changes that occur in microalgae cells under these space conditions could shed light on various aspects. For example, changes in the content of different cellular components could be observed or the molecular mechanisms of gravity perception could be uncovered. Data generation using flow cytometry or omics sequencing methods are more sophisticated and automated tools that would facilitate the achievement of these goals.