Space agencies and private companies already have advanced plans to send humans to Mars in the next few years – ultimately colonising it. And with a growing number of discoveries of Earth-like planets around nearby stars, long-distance space travel has never seemed more exciting.
However, it isn’t easy for humans to survive in space for sustained periods of time. One of the main challenges with long-distance space flight is transporting enough oxygen for astronauts to breathe and enough fuel to power complex electronics. Sadly, there’s only little oxygen available in space and the great distances make it hard to do quick refills.
But now a new study, published in Nature Communications, shows that it is possible to produce hydrogen (for fuel) and oxygen (for life) from water alone using a semiconductor material and sunlight (or star light) in zero gravity – making sustained space travel a real possibility.
Using the unbounded resource of the sun to power our everyday life is one of the biggest challenges on Earth. As we are slowly moving away from oil towards renewable sources of energy, researchers are interested in the possibility of using hydrogen as fuel. The best way to do this would be by splitting water (H2O) into its constituents: hydrogen and oxygen. This is possible using a process known as electrolysis, which involves running a current through a water sample containing some soluble electrolyte. This breaks down the water into oxygen and hydrogen, which are released separately at the two electrodes.
While this method is technically possible, it has yet to become readily available on Earth as we need more hydrogen related infrastructure, such as hydrogen refilling stations, to scale it up.
Hydrogen and oxygen produced in this way from water could also be used as fuel on a spacecraft. Launching a rocket with water would in fact be a lot safer than launching it with additional rocket fuel and oxygen on board, which can be explosive. Once in space, special technology could split the water into hydrogen and oxygen which in turn could be used to sustain life or to power electronics via fuel cells.
There are two options for doing this. One involves electrolysis as we do on Earth, using electrolytes and solar cells to capture sunlight and convert this into a current.