A robotic rover sent to Mars on a three-month mission clocked up 5,000 martian days exploring the Red Planet today. 

NASA’s Opportunity rover, which resembles animated movie hero WALL-E, bounced to a landing on Mars on January 25th, 2004.

It was not expected to survive a martian winter. But incredibly, it is still trundling about exploring the planet more than 14 years later.

A day on Mars is called a sol and lasts about 40 minutes longer than a day on Earth because the planet rotates slightly more slowly.

Opportunity – or Oppy to its fans – has long outlasted its twin rover, Spirit, which landed three weeks earlier but fell silent in March 2010 after becoming trapped in sand. Opportunity has survived dust storms and a software failure in its memory banks.

Opportunity, which is the size of a golf-cart, has driven over 28 miles from its landing site in Meridiana Planum to a spot called Perseverance Valley, on the edge of Endeavour Crater.

It has taken around 225,000 pictures of its surroundings, discovering evidence that Mars was once awash with water. A shoulder joint failed early on in the mission, but the ingenuity of NASA engineers got round the problem.

On its slow crawl across the martian surface, the rover has studied several craters and found a number of meteorites, such as this one, lying on the ground.

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

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

This writer has blogged support before for Opportunity elsewhere when its mission appeared to be in danger of being curtailed.

Skymania asked space evangelist and Opportunity’s biggest fan, Stuart Atkinson, who writes the fabled Road to Endeavour blog, what he reckoned were the rover’s greatest moments.

He replied: “Oppy achievements:

* Finding rocks and minerals modified by water RIGHT UNDER HER NOSE after landing – no need to go roving around looking for them ?.

* Finding the “Heat Shield” meteorite right next to the – surprise – wrecked heat shield… and then finding more than half a dozen more en-route to Endeavour Crater.

* Imaging Comet Siding-Spring in the martian sky (close approach comet).

* Reaching Victoria crater – it was a big ask getting there, but she managed it.

* Reaching Endeavour crater – that seemed impossibly far away from Victoria. But she did it.

But mainly, for me, just staying “alive”, beating everything Mars threw at her. Dust storms, failed joints, freezing martian winters… she beat them all.

These aren’t “scientific discoveries”… it’s not my place to say which are the most important of those… more like “highlights of the trip” ?