NASA today declared that the Mars rover Opportunity was dead. The announcement comes after hundreds of attempts to communicate with the rover have failed, included some radio signals sent as recently as last night. NASA's Opportunity Mission Directorate reported "Opportunity remains silent."
Opportunity originally touched down on Mars on January 25, 2004 and began its explorations of Mars' surface. Opportunity's was designed for a mission duration of 90 days. With the announcement today, Opportunity's actual mission duration has been slightly over 15 years. Opportunity holds the record for off-world driving with a total of 28.08 miles traveled. The rover's twin - Spirit - was also designed for a 90 day mission on the suface of Mars, but managed to continue operating until it became stuck in the sand in 2009; NASA officially ended Spirit's mission in 2011.
Curiosity - a larger rover - continues to opertate on Mars and NASA plans for another Mars rover missions beginning in 2020.