A drive of 157 feet (48 meters) on July 27 put Opportunity’s total odometry at 25.01 miles (40.25 kilometers).This month’s driving brought the rover southward along the western rim of Endeavour Crater. The rover had driven more than 20 miles (32 kilometers) before arriving at Endeavour Crater in 2011, where it has examined outcrops on the crater’s rim containing clay and sulfate-bearing minerals. The sites are yielding evidence of ancient environments with less acidic water than those examined at Opportunity’s landing site.
If the rover can continue to operate the distance of a marathon — 26.2 miles (about 42.2 kilometers) — it will approach the next major investigation site mission scientists have dubbed “Marathon Valley.” Observations from spacecraft orbiting Mars suggest several clay minerals are exposed close together at this valley site, surrounded by steep slopes where the relationships among different layers may be evident.
The Committee to Nuke Elysium 