NASA this week announced its Mars Exploration Rover Spirit discovered a patch of land on Mars that revealed the possibility of a past environment able to sustain microbial life.

While exploring a scientifically important area of Mars last May, Spirit, while dragging a broken wheel on the surface, discovered a patch of "nearly pure silica" found the Home Plate section of Mars.  Scientists believe it came from a hot-spring or fumarole -- an environment which forces acidic steam to rise through cracks on the planet's surface, also stripping mineral components while leaving only silica behind.

Even though the rovers were not designed to evaluate possible signs of life, each discovery like this one provides pieces to a complicated puzzle on Mars.  Researchers hope to have the opportunity to study this specific location on Home Plate when new missions are launched to the Red Planet.  The Mars Science Laboratory (MSL), scheduled to launch in September 2009, will be NASA's first chance to head back to Home Plate.

"Whichever of those conditions produced it, this concentration of silica is probably the most significant discovery by Spirit for revealing a habitable niche that existed on Mars in the past," said Steve Squyres, principal investigator for data gathered by the rovers.

Spirit now has only two weeks to safely arrive at a sun-facing slope on Home Plate before strong dust storms paralyzes it for the winter.