Microalgae Cultivation at Spaceship EAC for Advanced Life Support Systems

Kurzfassung

Efficient Life Support Systems (LSS) are essential for long-term crewed space missions. In this context, resupply mass is a crucial factor due to immense resulting costs. Resupply mass can be minimized by processing and recycling available goods using regenerative LSS technologies. A specific type of regenerative LSS, called bioregenerative LSS, utilizes biochemical processes. In this study, the C.R.O.P.® filter system and a Photobioreactor (PBR) as two potential parts of a bioregenerative LSS were investigated. The C.R.O.P.® filter system processes synthetic human urine into a fertilizer solution. The fertilizer solution can be used for algae cultivation in a PBR system. Algae conduct photosynthesis and produce edible biomass and oxygen, which can be provided to humans. Investigations in this study focused on the nitrogen supply to the microalgae Chlorella vulgaris by the C.R.O.P.® fertilizer solution. The aim of this study was to evaluate the cultivation of C. vulgaris by use of C.R.O.P.® solution as a nitrogen source. Herein, a fully operational PBR system was put into operation at the Gravitational Biology department of the German Aerospace Center’s Institute of Aerospace Medicine in Cologne. Results of two conducted cultivation experiments with approved nutrition served as data references. The feasibility of using the C.R.O.P.® solution as growth medium for algae cultivation was successfully proved during a third cultivation experiment. The results showed, that algae doubled their biomass within five days, using the C.R.O.P.® solution as a nitrogen source. Future research on algae cultivation using the C.R.O.P.® solution shall be facilitated by an automated interaction between PBR and C.R.O.P.® system. Therefore, a basic concept of automated interaction between the PBR and the C.R.O.P.® system was created.