Bedrock in Mars’ Gusev Crater Hints at Watery Past NASA

Now that NASA’s Mars Exploration Rover Spirit is finally examining bedrock in the “Columbia Hills,” it is finding evidence that water thoroughly altered some rocks in Mars’ Gusev Crater. Spirit and its twin, Opportunity, completed successful three-month primary missions on Mars in April and are returning bonus results during extended missions. They remain in good health though beginning to show signs of wear.