Washington: The white material on Mars uncovered by the robotic arm of the Phoenix probe is ice, scientists at the US space agency NASA have said.

"We have found proof that this hard bright material is really water ice and not some other substance," Peter Smith of the University of Arizona said in a transcript of a press briefing released late on Friday.

Since Phoenix landed on Mars in May, it has been digging around its landing spot near the north pole. Mars programme scientists have been using a "follow the water" strategy in exploring Mars, with a view to sending a human mission there some day.

The ice has not yet been analysed, but the behaviour of the white stuff spotted from a camera image delivered the evidence, scientists said. The chunks that Phoenix uncovered on Sunday were still present the next day but had vaporized by Thursday, said Mark Lemmon of Texas A&M University. If the white stuff had been carbon-dioxide ice, it would not have remained stable for even a day as a solid, he said.

Last week,the $420 million Phoenix managed to fill one of its ovens with dirt and began to bake and analyse the contents. The next step will be to recover ice and put it in the oven for analysis.

The first evidence of water on Mars was found by the Odyssey orbiter in 2002, and NASA has now the rover on the northern area of the planet, where it believes there are heavier concentrations of ice in the ground.

Source : IANS