Article Posted on : - Oct 29, 2010

This mosaic of images shows the soil in front of NASA's Mars Exploration Rover Spirit after a series of short backward drives during attempts to extricate the rover from a sand trap in January and early February 2010. Photo: NASA

PASADENA (BNS): The trapped NASA Mars robot Exploration Rover Spirit has found evidence of subsurface water on the planet.

According to the NASA, the water present there can be a snow melt or frost. These newest Spirit findings contribute to an accumulating set of clues that Mars may still have small amounts of liquid water at some periods during ongoing climate cycles.

Scientists from rover team have found stratified soil layers with different compositions near to the Mars surface and proposed that, thin films of water may have entered the ground from frost or snow.

The relatively insoluble minerals near the surface include what is thought to be hematite, silica and gypsum. Ferric sulfates, which are more soluble, appear to have been dissolved and carried down by water.

"The lack of exposures at the surface indicates the preferential dissolution of ferric sulfates must be a relatively recent and ongoing process since wind has been systematically stripping soil and altering landscapes in the region Spirit has been examining," Ray Arvidson of Washington University in St. Louis, deputy principal investigator for the twin rovers Spirit and Opportunity, said.

The twin Mars rovers finished their three-month prime missions in April 2004 and then kept exploring in bonus missions.

In April 2009, Spirit's left wheels broke through a crust at a site called "Troy" and churned into soft sand. A second wheel stopped working seven months later. The rover has entered in a hibernation-mode state on March 22.

Currently, NASA is using the Deep Space Network and the Mars Odyssey orbiter to listen if the rover reawakens.

The Phoenix Mars Lander in 2008 and observations by orbiters since 2002 have identified buried layers of water ice at high and middle latitudes and frozen water in polar ice caps.

Spirit, Opportunity, and other NASA Mars missions have found evidence of wet Martian environments billions of years ago that were possibly favourable for life.