The Spirit Mission, originally planned for 90 Martian Days of surveillance, has gathered over 1,400 Martian days on the station. But the images the rover sent to NASA specialists early this year made an impact on the scientific community: could past life on Mars be possible?

In March 2007, the team of researchers at NASA received images from the Mars Spirit rover of a patch of soil that proved to be rich in silica, which according to scientists could be a proof that water played an important role in creating it. Furthermore, on the origins of the water, scientists assume that it could have come either from a hot-spring, similar to a geyser, or from a fumarole in which acidic streams rise through the cracks. In either case, both of these situations indicate the presence of microbial life on Earth.

"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. The evidence is pointing most strongly toward fumarolic conditions, like you might see in Hawaii and in Iceland. Compared with deposits formed at hot springs, we know less about how well fumarolic deposits can preserve microbial fossils. That's something needing more study here on Earth," said Steve Squyres, lead scientist in the rover’s mission.

Although scientists haven’t decided on the origin of the silica, Squyres tends to believe the second possibility, with the following explanation: the deposits found on Mars have a great level of titanium, which is often encountered in Earth’s fumarolic deposits. This could mean that there might have been favorable conditions for microbial life in the past.

The possible explanations could generate even more hypotheses on the matter, but NASA scientists are very excited about this remarkable discovery. With Martian winter on the way, analyzing the newly discovered soil sample will become even more difficult, as the Spirit rover will be forced to reduce its activity, due to the reduced amount of sunlight available during this season.