Inside the flat panel reactor, algae turn water and CO2 into oxygen and food.

Inside the flat panel reactor, algae turn water and CO2 into oxygen and food.

Fabian Schmidt writes in DW about Jens Bretschneider, at the Institute for Space Systems, in Stuttgart, Germany. The scientist is exploring new solutions to the challenge of surviving without the luxury of regular, fresh supplies, as people start traveling farther away from Earth. His team thinks the answer lies in biological systems, like microalgae: “They make it possible to collect exhaled CO2 and create new oxygen, and at the same time build up biomass stocks,” he says.

Brettschneider is working with a flat panel reactor, “with which we can cultivate algae on Earth in an efficient way. The advantage in space is that the gas is mixing with the algae constantly. That gives us a large contact area. We agitate the algae so that they move towards the light, and then move away from the light again – and that encourages them to grow faster.”

There are other types of algae that produce hydrogen instead of oxygen. These algae are anaerobic – living in a reactor without oxygen. If one combines reactors with both types of algae, one can produce both oxygen and hydrogen. And, using fuel cells, one can create energy – with the production of water as a side effect.

“So you get this great circulatory system going, involving energy, food, oxygen and CO2. It’s enabling us to close a few gaps in the life support system,” Brettschneider says, pointing out the nutritious benefits of the reactor-made algae: “You can make it into a really nice paste, using a microwave or a ball mill, and mix it into your food. We can cover about 20 percent of an astronaut’s daily nutritional requirements with microalgae.”

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