NASA’s Opportunity rover sent back data to Earth showing that Mars once had benign, neutral-pH water flowing across its surface. That means that, at one time, the Red Planet had drinkable water.
The Opportunity rover, which landed on Mars in January 2004 along with its twin, Spirit, for three-month missions to search for signs of past water activity on the planet.
The robots, which are about the size of a golf cart, found the evidence, then kept exploring. Spirit stopped communicating with Earth in 2010 and was declared dead the next year. But Opportunity is still going strong.
The rover discovered clay minerals in an ancient rock on the rim of the planet’s Endeavour Crater. The minerals suggest that water was once present on Mars. Opportunity principal investigator Steve Squyers of Cornell University, explained, “This is water you could drink.”
Squyers added that the rock, called “Esperance,” stands out from other rocks, explaining:
“This is water that was probably much more favorable in its chemistry, in its pH, in its level of acidity, for things like prebiotic chemistry — the kind of chemistry that could lead to the origin of life.”
While the Opportunity rover has seen signs of clay in rocks before, this was the highest concentration it has detected so far. The neutral-pH water that once flowed over the rock and generated the clays likely existed during the first billion years of Martian history. However, it is almost impossible to find out exactly when the clay formed without bringing the rocks back to Earth.
At the current time, none of the rovers on Mars’ surface have the ability to bring back samples. However, the Mars Curiosity rover has an onboard laboratory that allows researchers to find out the compositions of rock and other samples the SUV-sized robot collects. Several countries hope to plan a mission soon that will allow rovers to bring back samples to Earth.
Until then, scientists will continue to glean all the information they can using the rovers riding around on the Marian surface.
[Image via NASA/JPL-CALTECH/CORNELL/ARIZONA STATE UNIV.]