"We still need to understand the nature of that interaction, and better yet we need to understand if it was hot water, cold water, was it water in vapor phase, or was it really in the liquid phase."
Spirit finally set its drill bit into bedrock on Columbia Hills, a mineral-rich rise of land inside Gusev Crater where the rover landed more than seven months ago. Scientists believe the crater, which is bigger than Connecticut, once held a lake that might have been suitable for life to arise.
Initial studies around the landing site, however, proved fruitless.
Spirit's sister rover, Opportunity, landed three weeks later on the opposite side of the planet in an area known as Meridiani Planum and almost immediately found signs of an ancient salty sea. The rover is now inside a crater looking for information to help researchers determine how big the ocean was and how long it lasted.
Spirit's findings will take a while to analyze. The hints of past water come from high concentrations of sulphur, chlorine and bromine, which move easily in water, but also can migrate through volcanic gases, for example. The data came from analysis of an outcrop called Clovis, located about 30 feet (nine meters) above the desert plain.
"This is different from the rocks out on the plain, where we saw coatings and veins apparently due to effects of a small amount of water," said Squyres. "Here, we have a more thorough, deeper alteration, suggesting much more water."
Scientists are hoping to uncover evidence from rocks that were unaltered by whatever processes that occurred in Clovis, which is much softer than any rocks previously analyzed
"We have the 'after,' Squyres said. "Now we want the 'before.' If we're lucky, there may be rocks nearby that will give us that."
Opportunity also is giving the science team pause for thought. After carefully navigating down into a stadium-sized depression known as Endurance Crater, the rover has found a variation of the small, hard spheres that the science team nicknamed blueberries.
These particles have been found everywhere Opportunity has looked.
During a press conference on Wednesday, scientists announced they had discovered a new form of the blueberries throughout a reddish slab of rock called Bylot. The particles are rougher in texture, more varied in size and are the same color as the rock rather than gray.
"We really have no idea what this is," said Cornell University's Zoe Learner.
