Martian devils can create a rare ingredient in rocket fuel | Science

The red planet is a rich source of perchlorates, chemical compounds used in fertilizers and rocket fuel, which rarely form naturally on Earth. Laboratory experiments now suggest how unusual compounds are created on Mars: from electric fields formed by global dust storms, as well as vortices known as dust devils.

For more than 5 years, scientists have assumed that perchlorates are relatively common on Mars, thanks to evidence from the Phoenix Mars Lander and Curiosity rover. On Earth, the chemical reactions that generate these compounds are usually powered by sunlight. But atmospheric chemistry models suggest that simple sunlight is not enough to do the business on Mars. Instead, they indicate that strong electric fields, such as those created by static electricity during global dust storms, could degrade gases in the Martian atmosphere and thereby cause perchlorate-generating reactions. .

To test this notion in the laboratory, the researchers placed a mixture of gases representing the Martian atmosphere – 95% carbon dioxide, 2% nitrogen, 2% argon and 1% d & ## 39, oxygen – in a large room, with a source of chlorine, table salt. The researchers decreased the temperature and pressure in the chamber until they match conditions similar to those of Mars. They then exposed the mixture to electric fields of magnitude probably present in Martian dust storms and dust devils (seen from the orbit, above).

Almost immediately, some of the gases in the chamber broke down to form highly reactive and positively charged versions of carbon dioxide, carbon monoxide, and nitrogen molecules. Over time, the reactions generated significant amounts of chlorates (ions containing a chlorine atom and three oxygen atoms) and perchlorates. The team estimates that perchlorate formation rates in Martian dust storms could be 10 times higher than those caused by sunlight, researchers say. Earth and planetary sciences.

For astrobiologists, perchlorates intrigue. Although these substances are toxic to humans – and could potentially endanger potential human settlements on Mars – some microbes may use perchlorates to fuel their metabolism.