Spirit recently uncovered geological deposits on the planet Mars that shows where steam or hot water once interacted with volcanic rocks. If Mars is anything like Earth, such a mixture is a perfect place to find bacteria and, that means primitive life processes at work.

The rover found the piece of ground (in an area it is exploring informally called Home Plate) after damaging a wheel. Spirit has been dragging it along as it moves but, fortunately, made a trench in the ground with the dragged wheel. The action produced some disturbed soil that looked brighter in appearance when compared to the surrounding soil.

Spurred on by such a discovery, MER scientists found that the brighter-than-normal soil contained silica, which is an ingredient in glass. The scientists think that water may have dissolved the silica and then moved it as it traveled along. They say that geysers on Earth often produce such action. When such activity occurs, if microbial life is present, it is often times preserved. Scientists hope to be able to investigate the site further in future missions for this possibility.

However, the scientists also think acidic steam may have moved through cracks in rocks and, because of its acidic nature, removed all the minerals off the rocks, except for the silica. The scientists relate this idea to fumaroles on Earth, which are tiny cracks or long fissures (openings) in the Earth’s crust near volcanoes. The fumaroles eject out steam and gases (such as sulfur dioxide and carbon dioxide) from magma or hot igneous rocks, which then interact with groundwater.

In either case, such locations on Earth are filled with primitive microbial life, and scientists hope to be able to find evidence that life on Mars was once present in its distant past.

Although Spirit and Opportunity are not equipped to look for microbial life, scientists on Earth are looking in the future when other spacecraft can return to this site for further investigations on the possibility of past life on Mars.

In fact, one such NASA mission is called the Mars Science Laboratory (MSL), which is scheduled to launch in September 2009 for a landing on the Martian surface between July and September of 2010.

Another mission, which is still in the development stage, is called ExoMars. The European Space Agency (ESA) mission will also send a robotic rover to Mars. Officials at the ESA are hoping for a launch of its ExoMars mission sometime early in the 2010s.