A Martian Rock Called Chester Lake Reveals Bedrock

NASA's Mars Exploration Rover Opportunity is using instruments on its robotic arm to inspect targets on a rock called "Chester Lake."

Credit:  NASA/JPL-Caltech/Cornell/ASU

This is the second rock the rover has examined with a microscopic imager and a spectrometer since reaching its long-term destination, the rim of vast Endeavour crater, in August. Unlike the first rock, which was a boulder tossed by excavation of a small crater on Endeavour's rim, Chester Lake is an outcrop of bedrock.

The rocks at Endeavour apparently come from an earlier period of Martian history than the rocks that Opportunity examined during its first seven-and-a-half years on Mars. 

The robotic arm of NASA's Mars Exploration Rover Opportunity casts a shadow on a rock outcrop called "Chester Lake" in this image taken by the rover's front hazard-avoidance camera. The image was taken during the 2,710th Martian day, or sol, of Opportunity's work on Mars (Sept. 8, 2011).

Chester Lake, an exposure of bedrock on the rim of Endeavour crater, is the second rock approached by Opportunity for close inspection since the rover arrived at Endeavour in August 2011 after a three-year trek. The rock is on a low ridge called "Cape York," which is a segment of the western rim of Endeavour crater. Endeavour is about 14 miles (22 kilometers) in diameter.
Robotic arm of NASA's Mars Exploration Rover Opportunity casts a shadow on a rock outcrop called 'Chester Lake'
 Image credit: NASA/JPL-Caltech

Opportunity and its rover twin, Spirit, completed their three-month prime missions on Mars in April 2004. Both rovers continued for years of bonus, extended missions. Both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life. Spirit stopped communicating in 2010. NASA will launch the next-generation Mars rover, car-size Curiosity, this autumn for arrival at Mars' Gale crater in August 2012.
Contacts and sources:
Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
More information about the ongoing exploration of Endeavour's rim is at: http://news.wustl.edu/news/Pages/22660.aspx .

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover Project for the NASA Science Mission Directorate, Washington. More information about the rovers is online at: http://www.nasa.gov/rovers andhttp://marsrovers.jpl.nasa.gov and on Twitter a thttp://www.twitter.com/marsrovers .