The Mars Spirit rover, now into its third year of operation, has found compelling new evidence, the most substantial to date, of free flowing water existing on the Mars surface of long ago. Interestingly enough, the evidence was uncovered due to a malfunction on the part of the rover itself. One of Spirit's six wheels has jammed and no longer rotates, leaving it dragging through the Martian soil. While exploring the Gusev crater, the Spirit science team noticed that the drag marks exposed patches of brightly colored soil. When Spirit's onboard sensors examined these patches, they were found to be rich in silica - a substance created only in the presence of an abundant water source. The sample examined was shown to 90% silica by the rover's X-ray spectrometer.
"This is some of the best evidence Spirit has found for water at Gusev," said Albert Yen, a geochemist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. One possible origin for the silica could have been interaction of soil with acid vapors produced by volcanic activity in the presence of water. Another could have been from water in a hot spring environment. The latest discovery adds compelling new evidence for ancient conditions that might have been favorable for life, according to members of the rover science team."
Meanwhile, on the other side of the planet, Spirit's twin rover Opportunity continues to explore Victoria Crater, with the intention to send it into that geologic feature now that it has completed a circuit around the crater and discovered a potential path into the crater.