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Making oxygen in space more efficiently using magnets

With over 20 years of continuous human presence in space on the International Space Station (ISS), we’ve developed technology to keep astronauts safe and healthy during stays that typically last between six months and a year. But future crewed missions, like planned missions to Mars, will require a whole new approach to human spaceflight if they are to succeed. Recently, a group of researchers proposed a new way of making oxygen in space using magnets, which could help astronauts explore further in the future.

Current oxygen systems on the ISS work through the Oxygen Generation Assembly, or OGA. Taking water from the water recovery system, the OGA splits this into oxygen which is kept, and hydrogen which is mostly vented into space. However, this system is heavy, which makes it difficult to launch, and it would need to be more reliable if it were to be trusted for use on a long-term mission to Mars.

The new work from an international group of researchers suggests that a technique called magnetic phase separation could be more efficient for making oxygen in space. The problem in oxygen generation is how to separate gases from liquids. In the microgravity space, these gases don’t rise to the top and have to be spun out with a large, heavy centrifuge. The researchers propose using magnets instead of a centrifuge, by submerging a neodymium magnet into the liquid which attracts the bubbles to it.

The team was able to test its concept using a facility called a drop tower, a 146-meter tall structure that houses a steel tube from which all the air can be sucked out. A capsule is placed inside the tube and is dropped from a height of 120 meters, entering free fall to give 4.74 seconds of weightlessness during which time experiments can be performed. Even longer tests of over 9 seconds can be done using the tower’s “catapult mode,” where the capsule starts at the bottom of the tower and is catapulted to the top before falling back down.

“After years of analytical and computational research, being able to use this amazing drop tower in Germany provided concrete proof that this concept will function in the zero-g space environment,” said one of the researchers, Hanspeter Schaub of the University of Colorado Boulder, in a statement.

The research is published in the journal npj Microgravity.

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