On Earth, the production of oxygen from carbon dioxide is ensured by photosynthesis (e.g. microalgae, higher plants), which potentially produces edible biomass (e.g. vegetables, fruits). Within MELiSSA Loop, this function is performed by the photosynthetic compartments, with a clear intensification with the Photobioreactor (i.e. 4a).
Spirulina platensis (Arthrospira platensis) have been chosen for their light energy conversion efficiency, its high pH environment that reduces contamination, and their high nutritional value. This “simple microorganisms” is as well genetically robust and able to adapt to a wide range of culture conditions, including space radiations.
Challenges and approach of the research
Investigations on Arthrospira sp. growth demonstrated its metabolic regulations are mainly by light energy availability. Consequently, its growth is limited by light energy flux inside the reactor.
Many achievements have been obtained and lead to the positive results of 80 liters of microalgae to supply one person oxygen needs. All these achievements lead to real breakthrough innovations, such as the use of optic fibers or thin-plate technology for optimizing photobioreactor volumetric productivity.
Enabling the oxygen production and a food complement during spaceflight, means the technology function appropriately in the space environment. Therefore, a representative version of the process, called ARTEMISS, was installed onboard the International Space Station for few weeks.
This experiment provided results, about the growth of the cyanobacteria Arthrospira sp. and associated oxygen production.