NASA rover Curiosity finds water in Mars soil - report

The rover Curiosity has discovered water in fine-grained soil on the surface of Mars, NASA confirmed Thursday in a series of papers published in the journal Science.

Each cubic foot of Martian soil contains about two pints of liquid water, though the molecules are bound to other minerals in the soil.

Curiosity first landed on Mars in August 2012 on Gale Crater, near the equator of the planet. Its aim was to circle and scale Mount Sharp, in the middle of the crater, a five-kilometer-tall mountain that will help NASA understand the history of Mars.

NASA scientists released the first detailed, peer-reviewed results of Curiosity’s experiments done during its first four months on Mars in a series of five papers published in Science.

"We tend to think of Mars as this dry place -- to find water fairly easy to get out of the soil at the surface was exciting to me," said Laurie Leshin, dean of science at Rensselaer Polytechnic Institute and lead author on the Science paper that verified existence of water in the surface soil.

"If you took about a cubic foot of the dirt and heated it up, you'd get a couple of pints of water out of that -- a couple of water bottles' worth that you would take to the gym,” she said, according to the Guardian.

Curiosity found about 2 percent of the soil, by weight, was water by scooping dirt samples under its wheels and depositing them into an oven in a centralized compartment called Sample Analysis at Mars.

"We heat [the soil] up to 835C and drive off all the volatiles and measure them," said Leshin. "We have a very sensitive way to sniff those and we can detect the water and other things that are released."

The rover also found sulphur dioxide, carbon dioxide and oxygen as soil and minerals collected decomposed with increased temperature.

A main aim of Curiosity’s missions is to find out whether Mars was ever hospitable to life. Scientists believe water was once abundant on the surface of the planet, but it has since almost completely disappeared.

"The rocks and minerals are a record of the processes that have occurred and [Curiosity is] trying to figure out those environments that were around and to see if they were habitable," Peter Grindrod, a planetary scientist at University College London who was not involved in the analyses of Curiosity data, told the Guardian.

The other papers published in Science included x-ray diffraction images of the soil in an attempt to examine the crystalline structure of the minerals on Mars’ surface, and analysis of a volcanic rock called "Jake_M,” named after a NASA engineer. The findings show the rock was similar to a type found on Earth known as mugearite, often found on ocean islands and in rift zones.

The published results of Curiosity’s experiments are the beginning of insights into Mars expected to come in the next few years.

"It's the first flexing of Curiosity's analytical muscles," Grindrod said. "Curiosity spent a long time checking out the engineering, instruments and procedures it was going to use – these papers cover just that engineering period. The targets here weren't chosen because of their science goals as such but as good targets to test out the instruments."

Leshin said in addition to the excitement of exploring a new planet, the findings will help planning for any human mission in the future.

"I do think it's inevitable that we'll send people there and so let's do its as smartly as we can. Let's get as smart as we can before we go,” she said.

The soil on Mars also showed the existence of a chemical called perchlorate, which can be toxic to humans.

"It's only there at a 0.5% level in the soil but it impedes thyroid function," she said. "If humans are there and are coming into contact with fine-grained dust, we have to think about how we live with that hazard. To me it's a good connection between the science we do and the future human exploration of Mars."