A chemical reaction that recycles carbon dioxide into fresh oxygen could provide more sustainable life support for astronauts on the moon or Mars – and as a bonus, it also produces carbon nanotubes.
Missions to the moon or Mars could get more sustainable life support from a chemical reaction that turns the carbon dioxide exhaled by astronauts into carbon nanotubes and water – which is then converted into fresh oxygen.
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| Astronauts on the International Space Station need a sustainable supply of oxygen Shutterstock/Andrei Armiagov |
In initial experiments, the new method proved more efficient than the existing system used to recycle CO2 into oxygen on the International Space Station (ISS).
Zhaosheng Li at Nanjing University in China and his colleagues developed a method that continuously pumps CO2 and hydrogen into a chemical tank. There, the gases encounter a cobalt-based powder that can initiate a chemical reaction when exposed to light.
This reaction creates water, which can be converted to oxygen using an existing water-splitting method. It also grows tiny carbon nanotubes that could potentially prove useful for future space missions, for example in specialised materials.
The process achieved 68 per cent oxygen recovery efficiency, whereas the current technology used on the ISS has a theoretical maximum of 50 per cent oxygen recovery. If the reaction could boost oxygen recovery efficiency from 50 per cent to at least 75 per cent, it could reduce the space station’s water resupply needs enough to save more than $5 million per year.
“This is greatly achievable on Earth and might be translated into a great single supply technology in space,” says Volker Hessel at the University of Adelaide in Australia.
The method still has room for improvement. A better chemical catalyst could reduce the amount of methane – an unwanted byproduct – the reaction produces, as well as boosting the formation of carbon nanotubes, says Li.
Li says the researchers want to refine the chemical process in future studies. “We plan to develop a prototype for extraterrestrial tests in the near future,” he says.
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