NASA’s Mars rover Curiosity has completed its first Martian year in operation today, having been on the red planet for 687 Earth days, and it’s already completed its main objective by proving that Mars could have once supported microbial life.

Curiosity Celebrates Martian Anniversary With A Selfie

Curiosity found ancient Martian riverbed early in its mission

“One of Curiosity’s first major findings after landing on the Red Planet in August 2012 was an ancient riverbed at its landing site,” NASA wrote in a press release. “The site was once a lakebed with mild water, the essential elemental ingredients for life, and a type of chemical energy source used by some microbes on Earth. If Mars had living organisms, this would have been a good home for them.”

Of course Curiosity hasn’t actually found life on Mars (don’t worry, you’ll hear if it does), but even proving that it might have done so in the past helps researchers to better understand how the planet’s surface has evolved. Curiosity is now driving slowly to Mt. Sharp where it will analyze layered rocks that should shed light on climate change over Mars’s history. It has also been collecting samples along the way, including a stop to drill into a sandstone site this past spring, and it is still carrying some of these samples for further analysis.

Curiosity Celebrates Martian Anniversary With A Selfie

That trip is taking longer than expected (it’s gone 4.9 miles since it first landed on Mars) because the rover’s wheels have taken more of a beating than researchers expected. They’ve had to recreate the terrain as best they can and test different driving techniques to minimize damage, but they are still confident that the rover can get the job done.

“We are getting in some long drives using what we have learned,” said Jim Erickson, Curiosity Project Manager at NASA’s Jet Propulsion Laboratory. “When you’re exploring another planet, you expect surprises.  The sharp, embedded rocks were a bad surprise. Yellowknife Bay was a good surprise.”

Opportunity rover still going a decade later

The researchers haven’t mentioned any plans beyond Mt. Sharp, but they will put Curiosity to good use for as long as the rover keeps going – there are simply too many open questions to do otherwise. The Mars rover Opportunity has been going strong for more than ten years, while Spirit was operational for about six years before it finally ‘went silent’, as shown in a classic XKCD comic (Earth years, in both cases).