NASA’s Mars Opportunity rover was only supposed to last 90 “sols,” or Martian days, when it arrived on the surface of the Red Planet on Jan. 25, 2004. More than 14 years later, she’s still going strong, and as we reported recently just achieved its 5,000th sol on Feb. 17. But it’s the incredible story and discoveries of Opportunity that make this truly an incredible accomplishment by NASA.

The reason why the Opportunity mission was only supposed to last 90 sols was because scientists did not think the solar-powered vehicle would be able to endure even one Martian winter, but so far it’s been able to survive eight. The plucky rover’s endurance was so impressive that NASA named the region it was exploring “Perserverance Valley.”

And it has racked up an impressive list of accomplishments since it began its mission those many years ago. It has documented and characterized a huge range of rocks and soils, and discovered evidence of past water activity on Mars. Opportunity has also been able to send back atmospheric and astronomical data back to NASA.

Back in July 2014, the Opportunity rover achieved the longest off-world distance traveled of 40 kilometers, beating out the Lunokhod 2, which traversed 39 kilometers on the moon as part of a 1970s Soviet mission. And in March 2015, the Opportunity officially reached the distance run in a marathon race, traveling 42.195 kilometers, or 26.219 miles.

“Five thousand sols after the start of our 90-sol mission, this amazing rover is still showing us surprises on Mars,” said Opportunity Project Manager John Callas, of NASA’s Jet Propulsion Laboratory, Pasadena, California, in a statement.

“We’ve reached lots of milestones, and this is one more,” Callas added, “but more important than the numbers are the exploration and the scientific discoveries.”