Ever wondered how humans could live, breathe and work in space? Well, scientists have developed a way to mimic photosynthesis without plants in a move that could make life on Mars possible.
The process involves harvesting solar energy and storing it in chemical bonds (just as batteries store energy), which scientists can then convert into energy-rich products including fuel and fertilisers – as well as air to breathe. Essentially, this means capturing light and transforming it into useful chemicals – just like a plant does.
The energy conversion process “could certainly complement life support systems in space habitats,” Dr Katharina Brinkert, associate professor at the University of Warwick, told BBC Science Focus. “And on Earth, at the same time, we can actually introduce a more sustainable way of making chemicals…you would save potentially a lot of time and energy industry as well.”
Scientists at the University of Warwick, including Brinkert, are behind the development – in partnership with ESA, the Georgia Institute of Technology (USA), and the Centre of Applied Space Technology and Microgravity Centre in Germany.
As part of the Humans on Mars initiative, the breakthrough could help humans survive on the Red Planet. On Mars and elsewhere in space, light from the Sun is the main energy source.
So how does it work – and how could it allow life in space?
The scientists use semiconductors, which can absorb light in the same way that chlorophyll (the green pigment in plant leaves) can. Solar cells, for example, are stacks of semiconductors.
Once stored, the scientists convert the solar energy directly, using it to split compounds like water into oxygen and hydrogen. In a space setting, the oxygen would be essential for breathing while the hydrogen could be used to make fuel – including for spacecraft.
The process, according to the researchers, wouldn’t need big industry infrastructure or even electricity to work because it generates electricity internally. What’s more, it can produce other molecules depending on which semiconductor they use.
For example, the scientists hope to use this method to convert carbon dioxide in the atmosphere into ‘solar fuels’. While there is only a comparatively small concentration of the gas in Earth’s atmosphere, this could play a part in the fight against climate change. On Mars, the carbon dioxide concentration is incredibly high, at around 96 per cent.
The energy conversion process will be tested in a rocket in late 2024 or in 2025. During the mission, a rocket containing an experiment will fly to the borders of space and then return after five to six minutes in microgravity.
The researchers hope that, if it is successful, the process will have applications for life both on Mars and on Earth. This, according to Brinkert, will involve experts from a variety of fields in what she calls a “Manhattan Project for the energy challenge”.
“I think there's a lot to learn from each other because a lot of the problems we have for [travel in] space are so pressing that we cannot go to space unless we have solved them,” said Brinkert.
She added: “I think ultimately we're trying to solve the same problem, and that is on Earth we need more efficient, reliable, sustainable energy sources to tackle climate change. And, on the other hand, if you want to do bigger space exploration to the Moon and Mars, we need efficient, reliable, sustainable energy sources.”
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