Developing Photobioreactors for Microalgae Cultivation on the Moon – Technical Challenges, Research Plan and First Steps

Space agencies and commercial companies aim to go back to the Moon with the objective to eventually stay and build a permanently crewed lunar settlement. As these plans move forward, the need for sustainable life support systems that promote recycling and reduce resupply missions from Earth will become increasingly important. Among potential solutions, microalgae offer a promising approach to closing the loop due to their photosynthetic capabilities and efficient cultivation in photobioreactor (PBR) systems. While PBR systems to cultivate microalgae on Earth are being optimized for terrestrial gravity, these systems require significant adaptation for lunar application to ensure efficient algae cultivation for a long-term and large-scale human settlement. Cultivating microalgae in the lunar environment presents substantial challenges due to the Moon’s unique environmental conditions, such as reduced gravity, and mission related requirements, such as reduced crew time and limited resources. Therefore, this paper aims to provide a research plan on how to overcome the technical challenges involved in designing a PBR suitable for long-term and large-scale lunar habitats. Consequently, the technical challenges of the PBR and its subsystems regarding the integration and use in a large-scale lunar base are analyzed in this paper. Based on that, a research plan by the Professorship of Human Spaceflight Technology at the Technical University of Munich is outlined, which aims at developing a lunar-gravity adapted PBR system for a long-term and large-scale crewed lunar base. Initial efforts in developing the PBR system with its corresponding subsystems are presented and discussed. The proposed research activities and initial efforts represent a critical step towards developing a viable and efficient PBR system that supports a long-term and large-scale human base on the Moon.