Salts in Martian Soil point to a time when Mars had water

Some bright white and yellow Martian soil containing lots of sulfur and a trace of water that was hidden under a layer of normal-looking soil - that was until the Martian exploration rover Spirit's wheels churned it up while the rover was struggling to cross a patch of unexpectedly soft soil nearly a year ago. The right front wheel had stopped working a week earlier. In an effort to manuver the rover, NASA controllers reversed the rover and dragged the wheel backwards, to an area where the rover could position itself to recharge its batteries through the solar arrays. The soil proved unusually soft and a large amount of bright yellow material was uncovered. The material is sulfur-rich and consists of sulfate salts associated with iron, and likely calcium. "These salts could have been concentrated by hydrothermal liquid or vapor moving through the local rocks," said rover science team member Dr. Albert Yen, a geochemist at JPL.

submitted by Shaun A. Saunders