Spirit indicates past snowmelt on Mars

William Atkins
Friday, 29 October 2010 23:35

Science - Space

The NASA rover Spirit is stuck on the planet Mars. Even though it can't move anymore it doesn't mean the little robot is useless. Far from that, Spirit discovered water, probably as snow melt, trickled into the subsurface in the recent past.

 

 

According to the October 28, 2010 NASA media brief 'NASA Trapped Mars Rover Finds Evidence of Subsurface Water,' the composition of soil layers has NASA scientists thinking that ''¦ thin films of water may have entered the ground from frost or snow.'

NASA adds, 'The seepage could have happened during cyclical climate changes during periods when Mars tilted farther on its axis. The water may have moved down into the sand, carrying soluble minerals deeper than less-soluble ones. Spin-axis tilt varies over timescales of hundreds of thousands of years.'

Ray Arvidson is the deputy principal investigator for the Mars Exploration Rover (MER) mission for the two rovers Spirit and Opportunity.

Dr. Arvidson comments on this discovery: '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.'

Ferric sulfates are compounds made up of iron and sulfate, also called iron(III) sulfates.

A summary of their discovery is written up in the Journal of Geophysical Research under the title 'Microscopy analysis of soils at the Phoenix landing site, Mars: Classification of soil particles and description of their optical and magnetic properties.'

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