Hello All!   
       
   Opportunity Runs the First Martian Marathon   
       
   July 18, 2012: With all the fanfare about Mars rover Curiosity landing on the   
   Red Planet in August 2012, it's easy to forget that there's already a rover on   
   Mars-an older, smaller cousin set to accomplish a feat unprecedented in the   
   history of Solar System exploration.   
       
   Mars rover Opportunity is on track to complete the first extraterrestrial   
   marathon.   
       
   A marathon is 26.2 miles.  When Opportunity landed on Mars in 2004, NASA's   
   goal was to have the rover travel a meager 600 meters.  However, no one knew   
   what kind of "runner" Opportunity would turn out to be. As of July 2012,   
   Opportunity has traveled almost 22 miles - only 4.2 miles short of a full   
   marathon.   
       
   http://www.youtube.com/watch?v=DC-rvKjBHfE   
       
   A new ScienceCast video follows Opportunity as it runs the Martian Marathon.   
   Play it   
       
   Runner-author Hal Higdon once said, "The marathon never ceases to be a race of   
   joy, a race of wonder." That goes double for a marathon on another world where   
   every mile promises a new discovery.   
       
   Opportunity's prime mission is to search for signs of ancient water.  Today   
   the Red Planet is a bone-dry desert with a breathtakingly thin atmosphere,   
   conditions deadly to almost every known form of life on Earth.  Billions of   
   years ago, however, things might have been different. Many researchers believe   
   that Mars was warmer, wetter, and friendlier to Martian life. Opportunity's   
   job is to search for clues to that ancient time.   
       
   Just getting to the starting line was epic: "This particular marathoner had to   
   fly about 283 million miles across space before being unceremoniously   
   drop-bounced on the Martian surface," says Ray Arvidson, Mars Exploration   
   Rover Mission deputy principal investigator.   
       
   http://marsrover.nasa.gov/gallery/press/opportunity/20110607a/PIA14135_Eagle-   
   t o -Endeavour_br.jpg   
       
   The Martian marathon route. [larger image]  [press release] Like many   
   long-distance runners, Opportunity likes to "take it slow."  On a typical   
   drive day, the rover travels only 50 to 100 meters.  This gives the rover time   
   to pause and look for the unknown. It also allows Opportunity to take plenty   
   of photos along the way. Recently the rover sent home its 100,000th image, a   
   stunning panorama.   
       
   Opportunity first uncovered signs of water in deposits near the landing site   
   in Eagle Crater.  There were rocks that seemed to have formed in an ancient   
   shallow lake. Over the next four years, Opportunity scavenged ever larger and   
   deeper craters, finding more evidence of wet periods. Indications were,   
   however, that the ancient lake water might have been too acidic for life.   
       
   The metallic marathoner soon set its sights on Endeavour Crater - an enormous   
   pit 14 miles wide and hundreds of meters deep. Endeavour's depth would offer a   
   look farther back into the history of Mars, to a time when the water was   
   possibly less acidic. The marathon route crossing Mars' Meridiani plain to   
   Endeavor was a daring trek -with no aid stations anywhere.   
       
   Raging dust storms reduced the rover's solar power so much that Opportunity   
   almost entered the "sleep of death"; soft, sandy, wind-blown ripples trapped   
   the rover's wheels, and there was an injury:  A failure in Opportunity's right   
   front steering actuator made running forward tricky. Ever resourceful, the   
   rover ran part of its race backwards.   
       
   "The course took Opportunity over sedimentary bedrock made of magnesium, iron,   
   and calcium sulfate minerals -- further indications of water billions of years   
   ago," says Arvidson.   
       
   When the marathoner reached Endeavour Crater in August 2011, things got   
   interesting.   
       
   "Endeavor is surrounded by fractured sedimentary rock, and the cracks are   
   filled with gypsum. Gypsum forms when ground water comes up and fills cracks   
   in the ground, depositing hydrated calcium sulfate. This is the best evidence   
   we've ever found for liquid water on Mars."   
       
   The gypsum veins were likely formed in conditions more pH-neutral and possibly   
   more hospitable to life: Jackpot!   
       
   But this marathoner isn't done. Opportunity is doing so well that 26.2 miles   
   might not be the finish line after all.   
       
   "We have no plans to stop running," says Arvidson.   
       
   Extraterrestrial ultra-marathon anyone?   
       
       
   Author: Dauna Coulter| Editor: Dr. Tony Phillips | Credit: Science@NASA   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.8   
    * Origin: NCS BBS (1:3828/7)