The first Martian marathon was no easy trek: the Opportunity rover had to struggle through smooth, soft sand and clamber over sharp rocks. This is the sounds of the terrain it covered in its 11-year journey exploring the red planet.

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.

The Mars Exploration Rover, better known as Opportunity, has been beaming back images and data from our planetary neighbour since 2004. As as of today, it has travelled 26.219, making it the first little interplanetary explorer to complete a marathon.

Eleven years ago today—in fact, at this very minute (12:05 am ET)—NASA's Opportunity rover touched down on Mars for what was supposed to be a 90-day mission. Since then, Opportunity has proven to be an engineering marvel by traveling almost 26 miles on the Martian surface, more than any other off-Earth surface vehicle.

NASA has had some truly bad luck lately, underscored by the cancellation of an ambitious balloon mission due to a leak last week. Even Opportunity, the decade-old Mars rover that has surprised everyone by exploring for more than a decade after its mission ended, is showing signs of slowing down. Now, NASA has a plan…

NASA plans to extend seven of its ongoing planetary missions, a review panel announced yesterday. Two of the missions, the Lunar Reconnaissance Orbiter and the Mars rover Opportunity, were at risk of being shut down, but it was Mars rover Curiosity that drew the least-favorable reviews, and the harshest criticisms.

Spirit, Opportunity, and Curiosity have rolled their way into a special place in our hearts, as the first of our rovers to kick-off our exploration of other planets. But this six-limbed, flying rover with the ability to break apart into two separate robots definitely has us intrigued.

For an entire Martian year (or in Earth-time, July 16, 2006 - June 8, 2008), Opportunity snapped a picture of the sun's position in the sky every third day at 11:02 a.m. The result? This tracing of the teardrop-shaped path the sun follows in Mars' sky.

Check out this outstanding photo of NASA's intrepid Opportunity rover. The Agency's HiRISE camera caught a rare glimpse of the spacecraft on Valentine's day while orbiting high above the "Murray Ridge" section of the western rim of Mars' Endeavour Crater. Can you spot it?

When a rock suddenly appeared in front of the Opportunity rover on Mars last month, scientists were puzzled. Now, scientists at NASA's Jet Propulsion Lab say they've solved the mystery.

A mysterious rock suddenly appeared in front of the Opportunity rover's cameras on Mars, puzzling scientists who describe the rock as both "a total surprise" and "about the size of a jelly donut."

On January 4, 2004, the first of two identical robotic exploratory rovers, NASA's Spirit, snapped this stunning 360 degree image of its surroundings, moments after setting down on Mars. In the years to follow, both Spirit and its sister Opportunity helped revolutionize our understanding of the Red Planet.

When NASA's Opportunity rover launched on July 7th, 2003, expectations were modest. It would spend 90 Martian days exploring soil and rock samples and taking panoramas of the Red Planet; anything else would be a bonus. Nearly ten years after its initial shift was up, Opportunity is still going strong.