Spirit Rover on Mars finds water made 'silica-rich soil'

May 22, 2007

NASA's Spirit Rover on Mars has found "silica-rich soil" in Gusev Crater that scientists say is so rich that it would require that water have been present at some point, in order for the deposits to be there.

"You could hear people gasp in astonishment. This is a remarkable discovery. And the fact that we found something this new and different after nearly 1,200 days on Mars makes it even more remarkable. It makes you wonder what else is still out there," said Steve Squyres, principal investigator for the Mars rovers' science instruments at Cornell University located in Ithaca, New York.

The Martian soil was analyzed by Spirit's alpha particle X-ray spectrometer, and the soil was found to contain at least 90% pure silica. The findings were announced during a teleconference between Squyres and the other rovers' team members.

But Spirit did not make this discovery on purpose. One of the six wheels on the rover is no longer functioning, and where ever Spirit goes, a deep gash is left in the soil in its wake. That is what caused the soil to be exposed and this discovery to be made. Spirit has made other discoveries using this 'method'. Spirit had previously found other indicators of long-ago water at the site, such as patches of water-bearing, sulfur-rich soil and alteration of minerals.

"This unexpected new discovery is a reminder that Spirit and Opportunity are still doing cutting-edge exploration more than three years into their extended missions. It also reinforces the fact that significant amounts of water were present in Mars' past, which continues to spur the hope that we can show that Mars was once habitable and possibly supported life."

The discovery is being called the best one yet to support the theory that Mars once had an abundance of water on it.

"This is some of the best evidence Spirit has found for water at Gusev," said a geochemist at NASA's Jet Propulsion Laboratory in Pasadena, California, Albert Yen who also added that this is the best indication so far that there could have been "favorable conditions" for there to have been life on Mars in the past.

There are some interactions that scientists say could have caused the silica to be deposited, but all of them include water. One is that volcanic activity, which produces acid vapors, interacted with the water inside the soil. Another theory is an ancient hot spring located in the area.

Both Spirit, and its partner rover Opportunity have both been in operation on Mars for almost 1,200 days. Both of the rovers finished their initial mission back in 2004, but both have been operating since and making new discoveries.