With the planning of long-duration missions to the Moon and Mars, humanity is facing an increasingly acute problem of providing astronauts with oxygen to breathe. Right now, keeping people breathing aboard space stations is a complex and costly process, so future journeys into the cosmic abyss will require better technology.
The International Space Station (ISS) is one of the largest and most expensive projects in human history. It has been orbiting our planet for almost a quarter of a century now, and all that time scientists and technicians have had to solve many problems in order to keep the people inside alive and healthy.
The ISS crew consumes between 2.5 and nine kilograms of oxygen per day, a vital gas needed for human breathing. Today, the main method of generating it in space is through electrolysis of water: an electric current causes a water molecule to break down into its constituent oxygen and hydrogen.
The process is not cheap: not only does electrolysis use up precious electricity, but there is also the problem of efficient separation of the phases (liquid, water and gas), which has confronted mankind since the first space flights in the 1960s.
To imagine what it is, imagine a glass of soda. On Earth, carbon dioxide bubbles float up and leave the glass, but on board the ISS, under microgravity conditions, the bubbles will remain suspended in the liquid.
Now, to separate oxygen bubbles from the water "soda", the ISS uses massive centrifuges, which take up a lot of space and require a lot of energy: to use them on a long-distance space mission, and in the opposite direction from the Sun, is to run the risk of not having electricity at all.
But now, an international team of scientists from the USA and Germany seems to have found a possible solution to this technological snag. They have developed a way to effectively separate the liquid and gas phases in microgravity using magnets.
In Germany, in a special installation called the Bremen microgravity tower, scientists conducted an experiment under conditions simulating near-earth microgravity. It turned out that gas bubbles could "attract" and "repel" a neodymium magnet by immersing it in different solutions (such as pure water or manganese sulphate solution).
In the future, such technology could be used to develop new oxygen systems and provide hydrogen fuel for the engines of the ships that would carry the first humans to long-haul spaceflight. The magnets could also be used on Earth, for example, to purify sewage or polluted air.