Mars rover looking for evidence
2007-12-13 09:33
Washington - Spirit, one of the two US robots probing the surface of Mars, made a key find suggesting the existence of past microbial life on the Red Planet, Nasa mission scientists said this week.
Scientists have theorised that a patch of nearly-pure silica that Spirit discovered in May could have been formed by processes which on Earth establish conditions for microbial life, according to a report from Nasa's Pasadena, California Jet Propulsion Laboratory, which manages the rovers.
One theory is that the silica - the main ingredient for glass - was produced in a hot spring. The other is that it was generated in a fumarole, where acidic steam seeps through cracks in the planet surface.
Both types of environments on Earth are home to extensive microbial life, according to the agency.
"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, one of the main scientists directing the two rovers' scientific investigation of Mars.
"The evidence is pointing most strongly toward fumarolic conditions, like you might see in Hawaii and in Iceland," Squyres said.
The other rover, Opportunity, is halfway around Mars from Spirit, plumbing the soil for other signs of a formerly wet conditions - scientists believe that over millions of years the Red Planet has evolved from a wetter environment to the current dry landscape.
On Mars since January 2004, the two Rovers are currently being prepared for the third Martian winter, a process more difficult especially for Spirit than in the past, because the rover carries a lot of dust on its energy-providing solar panels.
"Spirit is going into the winter with much more dust on its solar panels than in previous years," said the JPL's John Callas.
"The last Martian winter, we didn't move Spirit for about seven months. This time, the rover is likely to be stationary longer and with significantly lower available energy each Martian day," he said.