Finding a Little More Breathing Space

Article excerpt

Ateam of Midland scientists is working with the US space agency NASA to help astronauts breathe in space.

As people breathe, they exhale carbon dioxide - in the open atmospheres of everyday life, this presents no problem.

But in the sealed atmospheres of spaceships and space stations, such as the massive international one now being built, the carbon dioxide levels continuously rise, causing breathing problems through inadequate levels of oxygen.

Although carbon dioxide is not in itself poisonous, too high a concentration can still kill by making the oxygen content in the air too thin.

The problem isn't new. The same situation exists in submarines after they submerge. But beneath the sea the problem is more manageable because the carbon dioxide can be absorbed into liquid solutions.

However, it is not appropriate to carry large amounts of absorbent solutions into space because of their weight and the extra rocket power needed.

But now scientists in Birmingham are looking at a new way of scrubbing the air, by using a natural product to turn carbon dioxide into salt.

At Chembiotech, a high-tech company based on the University of Birmingham Business Park, Dr John Kennedy and his team of seven have been working on a much lighter alternative - using a natural catalyst, an enzyme called carbonic anhydrase.

Dr Kennedy said: "The amount of carbon dioxide we breathe out is about four per cent and there is about 0.4 per cent in the air around us. But in an enclosed space, it rises quickly and if it were to reach about ten per cent, any astronaut would be in serious trouble.

"Carbonic anhydrase will convert carbon dioxide at about 20C into a carbonate ion, which can be used to turn what was a gas in to something which is solid. …