The space dumpling (inset) is one of many food items that astronauts could prepare on a six-month or longer space voyage using the closed-loop food system we propose.
Our system consists of two biological components, macroalgae (seaweed) and animal muscle cells, both grown in a patent, continuously flowed system. As designed, the waste of one chamber becomes the nutrients of the other. Referring to the diagram, carbon-dioxide rich water flows into the seaweed growth chamber (A). Oxygenated water (as well as other growth-promoting compounds the seaweed may secrete) flow into the bioreactor (B) (via a collection of thin, semi-permeable tubes) where the animal cells grow. This design lets oxygen and other small molecules diffuse into the sealed space where the cells grow (C) while letting the waste of the cells (nitrogenous waste, carbon dioxide, and other metabolites) flow back into the line that feeds the seaweed (D). There is an intermediate, post-processing step (not pictured) where waste that is toxic to the growth of the algae (like lactic acid) can be removed and repurposed (for example, in culinary applications).
The benefit of this system is that both the seaweed and animal cells can be harvested independently as food products (seaweed, as a garnish or vegetable; muscle cells can be collected into ground meat). A novel way to use both is to grow the muscle cells on the seaweed tissue. This “meat wrapper” can be used in combination with standard astronaut food as a way to contain crumbs and offer a novel eating experience in space (see inset).