Back in 2010, XKCD's Randall Munroe devoted a surprisingly moving webcomic to Spirit, NASA's ill-fated and ultimately abandoned Mars rover. Today's comic is about Spirit's twin, the apparently indomitable Opportunity, and its tone is markedly less sentimental.

For those of you keeping track at home, NASA's opportunity rover has now exceeded its projected mission duration by 3,987 days. That's almost 11 years. As of Tuesday, March 24, it had roved a total distance of 26.2 miles, marking "the first time any human enterprise has exceeded the distance of a marathon on the surface of another world," according to John Callas, project manager for the Opportunity mission at NASA JPL.

[XKCD]