NASA Says Water 'Drenched' Opportunity Site

NASA said Tuesday that the Opportunity rover has found definitive evidence that liquid water used to exist on Mars.

Associate administrator Ed Weiler said that the Meridiani Planum crater where Opportunity touched down was once drenched and that it would have been a "good, habitable environment."

Principal investigator Steve Squyres said that every science instrument on the craft had been used to confirm the findings. He said that several pieces of evidence came together to convince mission controllers the area was once submerged.

Some of the evidence included the formation of what have been called "blueberries," tiny rocks that are known as concretions. Also, rocks in the area have slot-like holes that are evidence of crystal formation on Earth. There was also evidence of lots of sulfur in the rocks, which Squyres said is evidence of water.

Opportunity and its twin, Spirit, have been on the martian soil since January searching for any signs the planet once had water.

Since NASA launched the twin robot geologists last summer, scientists hoped the rovers would find minerals that could reveal whether the planet ever was wet enough to support life.

Opportunity has been studying an outcropping of layered rock close to its landing site in a small crater. The other rover, Spirit, has been studying rocks and soil on the other side of the planet.

Since their January landings, the robots have performed well, except for a memory problem that disabled Spirit, which arrived first, for two weeks. The robots have dug trenches in the soil with their wheels and drilled holes in martian rocks for the first time.

Last week, the Jet Propulsion Laboratory, which runs the missions, said that Spirit had achieved several scientific milestones, even though it had yet to reach the possible lakebed material it was hoped would be exposed in the Gusev Crater.