Martian wind makes rocket fuel
Lab experiments show Red Planet whirlwinds can catalyse a key ingredient needed for powered space travel. Nick Carne reports.
One of the ingredients humans need to make in order to travel to Mars is already there in abundance. And now scientists think they know why: plasma chemistry.
Laboratory studies in the US suggest that perchlorates, the toxic chemical compounds used in rocket fuel and fertilisers, are created naturally on the Red Planet by static electricity inside storms and the whirlwinds known as dust devils.
These strong electric fields break down gases in the atmosphere, researchers led by Zhongchen Wu from Washington University in the US suggest, and this drives reactions that create perchlorates at a rate that could be as much as 10 million times higher than those driven by sunlight.
That’s significant, both because sunlight is the catalyst used on Earth to create them, and because perchlorates have important implications for Mars habitability.
To test their theory, the researchers created a mini Mars, combining 95% carbon dioxide, 2% nitrogen, 2% argon, and 1% oxygen in a large chamber to simulate the atmosphere. They then added salt as a source of chlorine, and decreased the temperature and pressure.
When the mixture was exposed to electric fields of the right magnitude, some of the gases quickly broke down to form highly reactive, positively charged versions of carbon dioxide, carbon monoxide, and nitrogen molecules. Over time, substantial amounts of chlorates and perchlorates were created.
The findings are reported in a paper published in the journal Earth and Planetary Science Letters.
Perchlorates were first detected in arctic Martian soil by NASA's Phoenix lander in May 2008, and there was even more excitement when the Curiosity rover found them in the Gale Crater, suggesting their distribution is widespread.