Analysis of soil samples from the surface of Mars has revealed that there is an abundance of water on the Red Planet. The astonishing results, which may have profound implications for any future human exploration of the Red Planet, were announced in the September edition of Science, a professional journal.
Working with samples taken from Gale Crater by NASA’s Curiosity rover, scientists have determined that each cubic foot of Martian soil contains about 1 liter – or 2 pints – of water which could, in theory, be extracted by human pioneers working on the surface. Lead author of the study, Laurie Leshin of Rensselaer Polytechnic Institute in Troy, N.Y. says that this equates to about 2 percent water by weight.
According to Leshin, the discovery was “a wow moment.” She told Space.com that “I was really happy when we saw that there's easily accessible water here in the dirt beneath your feet. And it's probably true anywhere you go on Mars.”
Soil samples collected by Curiosity during its first 100 days on Mars were sifted and deposited into its onboard laboratory, the Sample Analysis at Mars, or SAM. One of SAM’s three instruments, a gas chromatograph, then heated up a sample by passing extremely hot helium over it, before measuring the gases released from the soil. Sulphur dioxide and carbon dioxide were detected, but surprisingly, the most common gas released was water vapour.
Also identified was the presence of deuterium, a heavy isotope of hydrogen which has been detected in the Martian air in similar ratios. "That tells us that the dirt is acting like a bit of a sponge and absorbing water from the atmosphere,” Laurie Leshin said.
The extent of collectible water on Mars is of enormous importance to those planning the first human visits, as it would be almost impossible to transport sustainable quantities of water from Earth.
The news isn’t all good, however. SAM also detected significant amounts of oxygen and chlorine, which suggests that the Martian soil may also contain toxic perchlorate compounds. Perchlorates had been previously detected at the planet’s north pole in 2008 by NASA’s Phoenix lander, and the latest results indicate that they may be common on the Martian surface. The compounds are known to cause thyroid problems in humans, and this new information will be critical in planning a manned landing.
Laurie Leshin noted that although the levels are low – about 0.5 percent – they represent a potential hazard for pioneering astronauts. “If humans are there and are coming into contact with fine-grained dust, we have to think about how we live with that hazard,” she said. “To me it's a good connection between the science we do and the future human exploration of Mars."
Curiosity has now been exploring the Martian surface for just over a year, and scientists are optimistic that the adventure will continue for at least another 12 months. Curiosity lead scientist John Grotzinger has been overwhelmed by the success of the mission so far, saying that the rover’s instruments have all worked perfectly and that data collected will keep scientists busy for years to come.
Grotzinger told Space.com that “The amount of information that comes out of this rover just blows me away, all the time. She just keeps telling us more and more. One year into the mission, we still feel like we're drinking from a fire hose."
Grotzinger, like Leshin, is also aware that what Curiosity discovers and what scientists analyse in the months and years ahead will serve as a platform for the next phase of the great Martian adventure. According to Leshin, “I do think it's inevitable that we'll send people there and so let's do it as smartly as we can.” Now, thanks to data collected by Curiosity and analysed more than 40 million miles away, the good news and bad news about key substances in the Martian soil has made a planned colonization of the Red Planet seem a lot more feasible.