Second NASA rover finds signs of water on Mars

6.00pm

LOS ANGELES - The Mars rover Spirit found the first indications that small amounts of water may have welled up in the soil of Gusev Crater where the rover landed in January, a NASA scientist said yesterday.

The finding comes three days after NASA officials announced that Spirit's twin, Opportunity, had uncovered geologic evidence that its landing site on the other side of the Red Planet, the Meridiani Planum, once was covered with water.

Scientists working with Spirit deduced that water formed small holes, or vugs, and left mineral deposits in a rock nicknamed Humphrey. The rover drilled a 2-mm deep hole into Humphrey and examined its interior with instruments to determine its mineral composition.

"If we found this rock on Earth we would say this is a volcanic rock that has had a little bit of fluid move through it either when it formed or shortly thereafter," Ray Arvidson, deputy lead scientist at NASA's Jet Propulsion Laboratory in Pasadena, said.

"The best bet is that water was in the magma. I don't think it was a groundwater percolation but water that came up with the magma," he added.

The amount of water found at Gusev Crater -- a canyon the size of Connecticut that scientists believe is an ancient lake bed -- "is by no means the gobs of water at Meridiani, but it again demonstrates that when rocks are made on Mars, fluids are involved."

Spirit, now in the 61st martian day, or sol, of its mission, is making its way through a rock-strewn plain toward the Bonneville Crater, about 150 metres in diameter.

Scientists hope to direct the golf cart-sized rover to the rim of the crater and peer inside, or drive into it, in hopes of finding rocks from below the planet's lava-capped surface.

Along the way, the team of scientists and engineers will look for dark-coloured split rocks that they can use to verify the findings at Humphrey, Arvidson said.

"We will stress to the (drilling) team to make deeper holes to make sure we're not being fooled," he said. "We want to make sure we are not looking at dust that has infiltrated into the rock's surface."

Spirit has driven 195.2 metres from where it landed on January 3.

Its next task is to finish a 360-degree panorama of high-definition photos at a hollow nicknamed Middle Ground, where it has been parked for several sols, then drive 25 metres northeast toward Bonneville Crater.

The team working with Opportunity planned to examine a shallow bowl formation where spherical rocks nicknamed "blueberries" have accumulated to learn their composition.

Scientists first spotted the "blueberries" in an outcrop of bedrock in the crater's wall where Opportunity has been drilling and taking microscopic images since shortly after its January 24 landing. Its next target is an area of bedrock nicknamed The Dells, mission manager Matt Wallace said.

The finely layered bedrock gave Opportunity clear evidence that salt water once flowed or pooled on the flat, gray Meridiani Planum, scientists have said.

No evidence of life has been found on the planet's barren surface, but scientists said it once was habitable.

The strong evidence of water, the discovery of which was the goal of the $820 million rover missions, provides support to NASA's plan to eventually send a manned mission to Mars to search for further evidence of life.

- REUTERS