Microgravity Concentrator of Rapidly Reproducing Microalga for Utilizing of the Emitted Carbon Dioxide and for Obtaining Oxygen and Food Biomass for Feeding of the Crew of an International Space Station during Long Flights”

Abstract

The use of microalgae makes it possible to utilize the carbon dioxide formed as a result of the life of astronauts and replenish the atmosphere of the spacecraft with oxygen. At present, in the field of creating a perfect life support system (LSS) for the International Space Station (ISS), research is underway to utilize carbon dioxide and provide oxygen to the ISS atmosphere during long-duration manned flights on the Russian Segment of the ISS.
Today, with the help of a space photo bioreactor, experiments are being carried out on the ISS to determine the possibility of using microalgae to utilize carbon dioxide emitted by astronauts, to obtain oxygen and food biomass through microalgae photosynthesis.
However, the mere cultivation of microalgae in microgravity conditions is not enough for the utilization of carbon dioxide emitted by astronauts, the production of oxygen and food biomass through photosynthesis during long-term space flights, because the amount of microalgae (Chlorella) biomass used is limited, and the delivery of additional microalgae biomass to the ISS requires large financial costs and is not possible at all on an interplanetary spacecraft. In this regard, obtaining under microgravity conditions a concentrate of rapidly multiplying microalgae (Chlorella) from its nutrient medium, part of which will go as an additive to the diet of astronauts, and the rest of it and the purified nutrient medium will be returned to the photo bioreactor for growing microalgae in a closed cycle, with sufficient biomass to support the life of astronauts during a long space flight, is an urgent task.
The article presents the developed microgravity concentrator of rapidly reproducing microalgae for utilization of carbon dioxide, emitted by astronauts, generation of oxygen in the atmosphere of the International Space Station or an interplanetary spacecraft and obtaining food biomass as an additive to the crew's diet in quantities, sufficient for long-term space flights. The developed microgravity concentrator uses the effect of a direct electric current on a nutrient medium with microalgae, which allows to simultaneously generate microdispersed negatively charged hydrogen bubbles and a negatively charged catholyte near the cathode, which, as a result of the electrostatic force of attraction between the electrodes, form strong complexes: rapidly reproducing cells of microalgae + microdispersed hydrogen bubbles, concentrating throughout the anode zone, separated from the nutrient medium, which is localized throughout the cathode zone.
The conical shape of the concentrator chamber, containing complexes: rapidly multiplying microalgae cells + microdispersed hydrogen bubbles, concentrated along the entire anode zone, and a nutrient medium localized along the entire cathode zone, allows moving the separated components into different capsules under microgravity conditions. The nutrient medium separated from the cells and part of the concentrate of rapidly multiplying microalgae cells are returned to the photo bioreactor through a closed circuit for further cultivation of the microalgae, removal of carbon dioxide and replenishment of oxygen in the ISS atmosphere in quantities sufficient for long-term space flights. Much of the remaining concentrate of rapidly proliferating microalgae (Chlorella) cells is used as a dietary supplement for astronauts to ensure their performance during long-duration space flight.