A Nasa image shows a panoramic view of the Phoenix Mars Lander taken after it landed on an ice sheet in May 2008. (AP)

Los Angeles, Aug. 1 (Reuters): Nasa scientists said yesterday they had definitive proof that water exists on Mars after further tests on ice found on the planet in June by the Phoenix Mars Lander.

“We have water,” said William Boynton, lead scientist for the Thermal and Evolved-Gas Analyser instrument on Phoenix.

“We’ve seen evidence for this water ice before in observations by the Mars Odyssey orbiter and in disappearing chunks observed by Phoenix last month, but this is the first time Martian water has been touched and tasted,” he said, referring to the craft’s instruments.

Nasa yesterday also extended the mission of the Phoenix Mars Lander by five weeks, saying its work was moving beyond the search for water to exploring whether the red planet was ever capable of sustaining life. “We are extending the mission till September 30,” Michael Meyer, chief scientist for Nasa’s Mars exploration programme, told a televised news conference.

The extension will add about $2 million to the $420 million cost of landing Phoenix on May 25 for what was a scheduled three-month mission, Meyer said.

Phoenix is the latest Nasa bid to discover whether water — a crucial ingredient for life — ever flowed on Mars and whether life, even in the form of mere microbes, exists or ever existed there.

Phoenix touched down in May on an ice sheet and samples of the ice were seen melting away in photographs taken by the lander’s instruments in June. Boynton said that water was positively identified after the lander’s robotic arm delivered a soil sample on Wednesday to an instrument that identifies vapours produced by heating. Mission scientists said the extension would give time for more analysis of Martian samples. They plan to dig two additional trenches.