The first scoop of Martian soil analysed by NASA's Curiosity rover held about two per cent water, offering hope for hydrating humans who someday explore the Red Planet, scientists say.
"We saw Mars as a very dry desert and while this is not as much water you will find in Earth soil... it's substantial," said Laurie Leshin, lead author of the study in the journal Science.
In 0.03 cubic metres of Martian soil, about the size of a block that is a foot wide, tall and deep, "you can get maybe a couple of pints (0.47 litres) of water out of that," said Leshin.
No global space agency has plans to send people to Mars any time soon, but the US has said it hopes to launch the first humans there by the 2030s.
Signs of water on the dusty and dry neighbour to Earth are nothing new.
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Previous space missions have found evidence that Mars likely had water - whether in the form of ice, below-ground reservoirs or even the drinkable kind - perhaps billions of years ago.
But the latest evidence comes from a suite of 10 of the most sophisticated instruments ever sent to scour the Martian surface aboard the Curiosity rover, which touched down in 2012.
Leshin said the scoop that Curiosity analysed likely represents what could be found elsewhere on Mars, since the planet is coated with a thin layer of surface soil.
"We now know there should be abundant, easily accessible water on Mars," said Leshin.
"We probably can find it almost anywhere right on the surface under your feet if you are an astronaut."
