Recently, the use of magnetism has been proposed as a potential improvement in the production of oxygen for astronauts in space. This conclusion is from new research on magnetic phase separation in microgravity.
It is complex and costly process to keep astronauts breathing aboard the International Space Station (ISS) and other space vehicles. As we plan future missions to the Moon or Mars, better technology will be needed.
On the ISS, oxygen is produced using an electrolytic cell that splits water into hydrogen and oxygen, but then those gasses have to be taken out of the system. According to very recent research, using the same architecture for a mission to Mars would have significant mass and reliability penalties that it wouldn’t make any sense to use.
Since the early space flights in the 1960s, efficient phase separation in lower gravity settings has been recognized as a barrier to human space travel. This phenomenon is a challenge for the life support system onboard spacecraft and the ISS.
The underlying issue is buoyancy. Imagine a glass of fizzy soda. On Earth, the bubbles of CO2 float to the top, but in the absence of gravity, those bubbles have nowhere to go thus remain suspended in the liquid.
Currently, NASA employs centrifuges to drive the gasses out, but these machines are huge and require significant mass, power, and maintenance. Meanwhile, experiments have been conducted demonstrating magnets could achieve the same results in some cases.
Even though diamagnetic forces are well known and understood, their use in space applications haven’t been fully explored as gravity makes the technology difficult to demonstrate on Earth.
A research team was successful in experimental tests at a special drop tower facility that simulates microgravity conditions.
Here, the groups have developed a procedure to detach gas bubbles from electrode surfaces in microgravity environments generated for 9.2s at the drop Tower. This study for the first time demonstrates that gas bubbles can be ‘attracted to’ and ‘repelled from’ a simple neodymium magnet in microgravity by immersing it in different types of aqueous solution.
This could open up new avenues for scientists and engineers developing oxygen systems as well as other space research involving liquid-to-gas phase changes.
These effects have tremendous consequences for the further development of phase separation systems, such as for long-term space missions, suggesting that efficient oxygen and, for example, hydrogen production in water photo electrolytor systems can be achieved even in the near-absence of the buoyant-force.
After years of analytical and computational research, being able to use this amazing drop tower has provided concrete proof that this concept will function in the zero-g space environment.
More information:
Álvaro Romero-Calvo et al, Magnetic phase separation in microgravity, npj Microgravity (2022).
By Sanika Mungekar
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