Scoop up some soil on Mars, heat it up, cool down the steam and ... slurp, slurp! You've got water!
Mars might appear dry as a desert, but astronauts may someday be able to tap its soil to quench their thirst. Research recently published suggests that the soil from the Martian surface contains about 2% water by weight.
This is one of several insights emerging from data that the Mars rover Curiosity has been collecting. Five studies in the journal Science were published last week based on data from the rover's first 100 days on the Red Planet.
"The community was surprised that there was a large amount of water trapped in the ... Martian soil," said Chris Webster, manager of NASA's Planetary Sciences Instruments Office.
Curiosity, representing a $2.5 billion NASA mission, has been on Mars since it made a dramatic landing there August 6, 2012. Earthlings celebrated as the two-ton rover arrived, carrying with it the most sophisticated suite of instruments and cameras to explore the surface of another planet.
Thanks to Curiosity, scientists now know more than ever about the composition of the Martian soil.
"It's the first time that the soil has been analyzed at this level of accuracy," Webster said.
Turning on the faucet
The rover's Sample Analysis at Mars (SAM) instrument helped scientists probe the soil by heating a sample up to 835 degrees Celsius.
The gases that came off included oxygen and chlorine as well as water vapor. Based on the ratio of isotopes within, scientists believe this water is coming from the recent Martian atmosphere.
"If you take about a cubic foot of dirt with the amount of water that we found and heated it up, you could get a couple of pints of water out of that," said Laurie Leshin, dean of science at Rensselaer Polytechnic Institute in New York, who led this study. "It was kind of exciting to me to see that, wow, it would be a significant amount."
More broadly, the analysis gives us new information about the hydrological cycle on Mars, said John Grotzinger, lead scientist on the Curiosity mission.
"Somehow, there's a process on Mars where, even though there are just trace quantities of water in Mars's atmosphere, this noncrystalline material is able to absorb it like a sponge and bind it into its framework," Grotzinger said.
The technical details about how future astronauts would use the soil as a resource for water haven't been worked out, Webster said. A condenser would be required to cool the water steam into a liquid form after heating up the soil. But from what we know so far, he said, it would be drinkable.
"This is a reservoir for water on Mars that we had not really appreciated before," Grotzinger said.
Scientists are also learning about the diversity of the soil on Mars.
Pierre-Yves Meslin, a scientist at Universite de Toulouse in Toulouse, France, and colleagues used data from an instrument that fires a laser to analyze the soil and rock on Mars. It's called the ChemCam Remote Micro-Imager.
One main soil type on Mars, they said, is made of fine-grained particles and carries a significant amount of hydrogen. Scientists say this reflects the dust that covers the whole Martian surface. The dust that covers Mars is more akin to a fine sand than the fluffy film on the floors of neglected attics on Earth, Webster said.
The other main soil type was coarse and is local to Gale Crater, the area where the rover is exploring. These particles, up to 1 millimeter in size, reflects what rocks in this area are made of.
Previous rovers -- Pathfinder, Spirit and Opportunity -- had less sophisticated technology to analyze soil but their insights about the mineral composition of the Martian soil are similar to what Curiosity found, Meslin said.
With ChemCam and Curiosity's other instruments, the latest rover can give scientists a deeper understanding of the composition, as well as how this soil was formed.
Complications with organics
New scientific insights also present the issue of chemical compounds that may complicate the search for life on Mars.
Curiosity is not capable of detecting life directly; it wouldn't confirm either modern life or ancient fossil organisms. It can, however, determine if the ancient environment was habitable -- which the rover told us it was -- and look for organic compounds.