Posted: Sun, Jul 18, 2004, 10:54 AM ET (1454 GMT)
NASA's Mars Exploration Rover Spirit, moving backwards to deal with a faulty wheel, has encountered a bedrock outcrop that may contain some of the oldest rocks found yet during the mission. Spirit, which has traveled over 3.5 kilometers since landing in Gusev Crater, is now traveling backwards because of increased friction with the rover's right front wheel. By moving backward rover controllers effective drag the balky wheel along, rotating it only occasionally in rough terrain. Despite these problems, the rover continues to perform good science, and recently found a bedrock outcrop containing some of the oldest rocks found to date. Spirit is expected to find similar outcrops as it moves up the Columbia Hills. Meanwhile, Spirit's twin, Opportunity, continues to inch down into the crater Endurance. Scientists have found a puzzling increase in the amount of chlorine in the rock layers as Opportunity travels deeper into the crater.
