The much loved and long-running Opportunity rover has recently celebrated yet another major milestone; it spent it’s 5,000th day on Mars. Opportunity is a rover the size of a golf cart, which landed on the red planet in January of 2004 for a mission that was supposed to last for just 90 Martian days, or sols. As of February 16, it has spent 5,000 sols collecting data and sending it back to Earth.

Opportunity Project Manager John Callas reported that NASA scientists are still surprised by the data Opportunity has sent back from Mars. This data is thanks to surprisingly high-quality photos revealing discoveries such as rock strips and impact craters. Opportunity is technically classified as a geology robot and is controlled via remote from mission control in California. It was built to examine rocks on a microscopic level, determining their composition and transmitting that data back to Earth.

The rover has endured quite a lot while on its mission, including severe dust storms in 2011. In late 2014, NASA scientists worried that Opportunity had suffered a memory failure, as it failed to store information on its non-volatile memory. NASA overcame this issue by reconfiguring the rover to operate in RAM-only mode, bypassing the need to use non-volatile memory.

Spirit, Opportunity’s twin rover, landed on Mars a few weeks before Opportunity, and lasted until mid-2010. During its time in operation, Spirit captured 128,000 photos and drove across 4.8 miles of Martian sand. After struggling in the soft sand for about a year, NASA declared that rover dead, and focused its efforts on Opportunity. The small rover has logged over 28.02 miles, setting a record for the number of off-world miles driven by any vehicle. It has also transmitted approximately 225,000 images back to mission control.