NASA is celebrating the 12th anniversary of its Mars Opportunity rover this week.
The significant milestone is even more impressive because the plucky little robot was only designed to last for 90 days.
It took Opportunity over six months to reach the Martian surface , which it did on January 25, 2004.
The reason the NASA team behind the rover only calculated for 90 days was because of the extreme build-up of dust on Mars that would obscure the rover's solar panels

Luckily, wind storms on the Red Planet periodically wash over the rover and clean the solar panels, allowing it to collect power.
It's currently exploring an area known as Marathon Valley , an area rich in clay minerals, after travelling 26 miles from its initial landing site.
"Opportunity has stayed very active this winter, in part because the solar arrays have been much cleaner than in the past few winters," said Mars Exploration Rover Project Manager John Callas, of NASA's Jet Propulsion Laboratory, Pasadena, California.

NASA
The view from the Opportunity rover as it explores Marathon Valley

"With healthy power levels, we are looking forward to completing the work in Marathon Valley this year and continuing onward with Opportunity," Callas said.
Despite its amazing resilience, the intrepid rover is beginning to feel the effects of advancing age. It's becoming harder to maneuver and has had issues with memory storage.
It also costs roughly $14 million each year to keep Opportunity running. That's a drop in the bucket compared to the initial $400 million it cost to build it and get it to Mars.
Opportunity continues to study the geology of Mars and provides scientists with a huge amount of insight into our rocky neighbouring planet.