NASA Opportunity rover celebrates its 5,000th Martian day

Back in the summer of 2003, NASA launched a pair of Mars rovers named Opportunity and Spirit. Both landed on the Martian surface in January 2004, each designed for a mission that would last 90 Martian days (which are called sols). Both rovers managed to drastically outlive that 90-sol mission. Though Spirit became stuck in 2009, eventually losing communication with NASA, Opportunity lived on.

NASA has announced that this past Saturday was Opportunity rover's 5,000th sol spent on Mars. The rover has been successfully rolling around the Red Planet since its first Martian day of work back on January 25, 2004. The rover has proven incredibly capable; NASA admits that it expected the rover to perish during its very first Martian winter.

That didn't happen, though, to either rover, and though Spirit is no longer in use, Opportunity has managed to remain active through 8 Martian winters including the lowest-energy months (the rover is solar-powered).

During its time, Opportunity has sent back approximately 225,000 photos taken on Mars, all of which NASA has published online for anyone in the world to see. Opportunity is behind many notable discoveries, including revealing evidence of groundwater and surface water that existed in Mars' ancient past.

Researchers used Opportunity to investigate Endeavor Crater, among others, and is now using it to probe Perseverance Valley. The rover got to view its 5,000th Martian sunrise from the Endeavor Crater's eastern rim, and now it's back to work gathering more data to help researchers understand the distant planet.