NASA’s Opportunity rover landed on Mars the night of Jan. 24, 2004 PST (just after midnight EST on Jan. 25), three weeks after its twin, Spirit, touched down. Spirit stopped operating in 2010, but Opportunity is still going strong, helping scientists better understand the Red Planet’s wetter, warmer past.

via Mars rover Opportunity now in 10th year – Technology & science – Space – Space.com | NBC News.

I love this story because the requirements for these rovers only called for 3 months operation.  That is what they call exceeding expectations!