After investigating some flat, light and dark toned rocks around Spirit of St. Louis Crater in April, Opportunity chalked up another milestone achievement – the 4000th sol or Martian day of surface operations.
MER mission ops team members joined other engineers and scientists, some who previously worked on the MER mission, to take on the challenge of a relay marathon to celebrate Opportunity's milestone achievement.
On March 24, 2015, after spending several weeks investigating some new rock types along the western rim of Endeavour Crater, Opportunity roved past 42.2 kilometers (26.2 miles) and put the first off-Earth marathon in her rear view mirror, driving the Mars Exploration Rovers mission back into the space history books.
From the discovery of a new rock type to a successful flight software upload that should enable the robot field geologist to regain her long-term, flash memory, Opportunity and her team delivered what turned out to be a hugely productive and memorable 133rd month on the Red Planet.
On January 24th, something wonderful happened on Mars. Opportunity completed her 11th year of exploring the surface of the Red Planet! The veteran rover couldn't exactly go to Disneyland to celebrate this amazing achievement, so she did what she loves to do – roved on.
With a wonder year of discoveries, historic feats, and bummers in the rear view mirror – and plenty of mettle to continue exploring – Opportunity ended 2014 quietly working in a temporary back-up mode, as her colleagues on Earth ramped up for the mission's marathon adventure to come in 2015.